Flexor digitorum profundus
tendon excursions
during controlled motion after flexor tendon repair in zone II: A prospective
clinical study
Intratendinous metal markers were used to study flexor digitorum profundus tendon excursions during early controlled motion with dynamic flexion traction and to evaluate their significance for results after flexor tendon repair in zone II. The mean excursion was 1 mm along the middle phalanx and 5.6 mm along the proximal phalanx. This corresponded to a mean excursion per 10 degrees of controlled distal and proximal interphalangeal joint motion of 0.3 and 1.2 mm, respectively. Compared to active motion, controlled motion of the distal interphalangeal joint mobilized the tendon with an efficiency of 36% and controlled motion of the proximal interphalangeal joint mobilized the tendon with an efficiency of 90%. Controlled-motion excursions induced by the distal interphalangeal joint along the middle phalanx had little influence on subsequent active range of motion in the distal interphalangeal joint, whereas excursions along the proximal phalanx (for which the proximal interphalangeal joint was largely responsible) did have a significant influence on subsequent total active interphalangeal range of motion. (J HAND SURC 1992;17A:122-31.)
K. L. Silfverskiold, MD, E. J. May, BAppSc (OT), and A. H. Tiirnvall, Gothenburg, Sweden
A
dhesions and gap formation are considered the two major causes of poor results after flexor tendon repair in the hand. The various modifications of early controlled-motion programs in use today are designed to overcome these problems by promoting the excursion of repaired tendons without placing too much tension on the repair. There are many reports of improved clinical results with early controlled motion,‘-* and experimental studies in animals have confirmed a beneficial effect on the
From the Division of Hand Surgery, Department of orthopedic Surgery, and the Department of Diagnostic Radiology, Sahlgren Hospital, University of Gothenburg. The study was supported by grants from the Goteborg Medical Society, the Swedish Medical Society, the University of Gothenburg, the Greta and Einar Asker Foundation, and the Bertha and Felix Neubergh Foundation. Received for publication Sept. 11, 1990; accepted in revised form May 10, 1991. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: K. L. Silfverskiold, MD, Division of Hand Surgery, Department of Orthopaedic Surgery, Sahlgren Hospital, University of Gothenburg, 413 45 Gothenburg, Sweden. 3/l/31543 122
THE JOURNAL OF HAND SURGERY
MD,
repair process itself, including an increase in tensile strength and a decrease in adhesion formation.‘-‘3 The magnitude of tendon excursions occurring during controlled motion and their significance for clinical results are not clear, however. Although many authors have studied tendon excursions in a variety of experimental situations,‘4-24reports on tendon excursions in patients with flexor tendon repairs are few and are based on small or undefined groups of patients.25*26Studies linking tendon excursions during controlled motion with clinical results have not been reported to our knowledge. In this study we used a modification of a previously described method,‘*’ 27 incorporating intratendinous metal markers and x-ray examination techniques to study flexor digitorum profundus (FDP) tendon excursions in patients with flexor tendon repairs in zone II. We sought to answer the following questions: (1) How much does a repaired FDP tendon move during controlled motion with dynamic flexion traction? (2) What is the relationship between controlled joint range of motion and the corresponding tendon excursion? (3) How do controlled-motion excursions relate to those that occur during active motion? (4) What is the significance of controlled-motion excursions for adhesion formation and subsequent clinical results in terms of active range of motion?
Vol. 17A, No. 1 January 1992
Material From May 1987 to December 1988, 46 digits in 44 patients with uncomplicated complete FDP lacerations (with or without concomitant flexor digitorum superficialis lacerations) in zone II were operated on at the Hand Surgery Unit in Gothenburg, treated with dynamic flexion traction, and had metal markers implanted during the operations. Patients with associated injuries (other than digital artery and nerve injury) were not included in the study. Six of the original 46 digits were excluded-two because the patients disregarded instructions, two because the patients fell on the injured hands and ruptured the repairs, and two because of technically inadequate radiologic examinations. Another four digits completed the controlled-motion program and had adequate radiograms during this period but were then lost to followup. A total of 40 digits were thus assessed for tendon excursions during controlled motion and 36 of these for subsequent active range of motion 6 weeks and 1 year after operation. The mean age of patients was 32 years (range, 14 to 71 years, median, 30 years). Thirty digits (75%) belonged to men and 10 (25%) belonged to women. Relevant injury-related data are presented in Table I. Operative technique All operations were performed by the same group of specialist staff surgeons, using axillary blocks, loupes, and the same basic surgical techniques. The FDP was repaired with a modified Kessler technique with 4-O braided polyester and a 6-O continuous epitendinal stitch. The FDS was repaired with mattress sutures of 4-O braided polyester. The opened part of the sheath was adapted loosely over the repair. Two metal markers were placed in the FDP tendon a few millimeters proximal and distal to the core stitch. They consisted of 2 to 3 mm long segments of 5-O multifilament stainless steel suture with a knot in the middle. The knotted segment of the suture was pulled into the tendon after the suture needle was passed transversely through it. Both ends of the suture were cut flush with the sides of the tendon while the tendon was gently compressed with a smooth forceps. A third reference marker was placed between the other two by attaching a small single stitch of 5-O stainless steel to the dorsal periosteal rim of the sheath. The hand was immobilized in a dorsal plaster splint from below the elbow to the fingertips, with the wrist in approximately 30 to 45 degrees of palmar flexion, the metacarpophalangeal (MP) joints in 50 to 70 degrees of flexion, and the interphalangeal (IP) joints straight.
Flexor digitorum profundus tendon excursions
123
Table I. Injury-related data (n = 40)
Dominant hand Index finger Long finger Ring finger Small finger FDP + FDs* One digital nerve Two digital nerves Delayed operationt
No.
%
19
47.5
10
25
5 7
12.5 17.5
18 19 12 4 8
45 47.5 30 10 20
*Only complete FDP + PLX lacerations. TMore than 24 hours after injury.
Postoperative
treatment
Controlled mobilization was begun on the first to third postoperative day, using the same type of plaster of Paris splint and the joint positions described above. Ten active IP joint extension exercises were performed hourly against the flexion force of dynamic traction attached to the tip of the injured finger. Three different traction techniques, described in a previous article,28 were used. The tension was adjusted to produce as much IP joint flexion as possible without restricting the patient’s ability to achieve full extension. The patients were instructed not to actively flex any of the fingers. After 4 weeks of controlled mobilization, the splint was removed and active movements were commenced, which for another 2 weeks consisted of only unresistive flexion-extension exercises. Gentle resistive flexion exercises were commenced at 6 weeks and progressive resistive exercises, including blocking of the PIP joint (for differential gliding), after the eighth postoperative week. Full-power gripping was not allowed until 3 months postoperatively. Extension deficits were treated with dynamic Capener-type splints after the sixth postoperative week. All patients were reviewed regularly by the operating surgeon and the hand therapist (E. J. M.) who supervised all therapy. To get a full year’s undisturbed follow-up of all patients, no operative procedures to improve tendon function were performed during this time. Calculations of excursions and joint motion Tendon excursions were calculated from measurements on x-ray films obtained under standardized conditions by specially trained staff members. Each examination included one frontal view and two lateral views of the injured finger and a reference millimeter scale placed immediately adjacent to the finger in a plane level with and parallel to the repaired tendons. The initial position and orientation of the markers were
124
The Journal of HAND SURGERY
Siljiwrskitildet al.
Fig. 1. Radiographs in extension (A) and flexion (B) of a controlled-motion periosteal marker placed between two intratendinous markers.
established on films taken on the first postoperative day with the IP joints still immobilized in extension. One and 3 weeks after operation radiographs of a controlledmotion exercise were taken in extension and flexion (Fig. 1). When active movements were well established, between 3 and 6 months after the operation, a final set of radiographs during active motion was obtained in the 36 digits remaining for full follow-up. To determine excursions, we recorded the change occurring in the position of an intratendinous marker in relation to the fixed periosteal marker during flexion and extension of the digit. The movement of the marker (and, accordingly, the tendon) was assumed to occur along a linear path. Although ours was not computerized, the method for measuring excursions was thus essentially the same as the one described by Horibe et a1.24All measurements were performed with a micrometer, calibrated against the reference scale and adjusted to the nearest 0.5 mm level. The magnitude of errors due to inaccurate placement of the scale was calculated theoretically and confirmed by practical trials. A 1 cm difference in level between scale and finger involved an error of approximately 1% . A 1Sdegree discrepancy
exercise,
showing one
of angular position between scale and finger produced an error of 3.5%. During the actual examinations the errors were considerably smaller and therefore were considered negligible. The position and orientation of the markers were checked on equivalent views during the follow-up period to ensure that they remained in place. Adequate excursions during active motion also indicated that they remained within the tendon. At the final examination one marker had changed orientation on frontal views. Its exclusion did not affect subsequent calculations. IP joint motion was measured with a goniometer on the same radiographs used for recording excursions. Clinical recordings of active range of motion were performed by one of us (E. J. M.) at 6 weeks and 1 year after the operation. All measurements of joint motion were adjusted to the nearest 5-degree level. Analysis of excursions The excursion of a tendon is the sum of excursions produced by motion in each of the joints distal to the measuring point. 24.29Therefore calculations of tendon excursions in zone II must be related to both the mea-
Vol.
17A, No.
1
January 1992
Flexor
digitorum
profundus
Table II. Tendon excursions, the corresponding joint range of motion and excursions joint motion during the controlled motion period at 1 and 3 weeks after operation
Results
are expressed
technically
groups
3 weeks (n = 171
I weeh (/I = 25)
5.6 (3.5)
5.6 (3.5)
0.9 (0.7)
71
71 (29)
(31)
standard
the number
deviations
of digits
29
0.8 (0.3)
0.8 (0.3)
as means with
In each of the three
I week (n = 13)
varies
PIPi 3 weks fn = 2Y)
I (0.9)
5 (3.1)
5.5 13.8) 46
0.3 (0.2)
0.3 to.?,
1 tiwks 01 = 10)
I wek (n = 71
30 (15)
(141
125
per 10 degrees of
DIP+
DIP + PIP*
Tendon excursion (mm) Joint motion (degrees) TE / 10 degrees
tendon excursions
40
(23)
(20)
1.2 (0.3)
1.1 (0.6)
in parentheses. slightly
because
a feu
patient\
did
not attend
both examinations
or because
one of the eummations
wah
inadequate.
‘Equivalent
to cxcurs~ons
measured
at proximal
tEquivalent
to excursions
measured
at middle
SExcurwns
calculated
by deducting
middle
phalanx phalanx
phalanx
level. level.
excursion
from
proximal
Table III. The relationship
between tendon excursions per 10 degrees of joint motion)
phalanx
excursion
in ale\
during controlled
wth
markers
at both
levels.
and active motion (&millimeters
TEIIO” Controlled motion Mean DIP
+
PIP
0.8
0.4
I .2*
0.3
DIP
(n
=
22)
0.3
0.2
0 9:
0.7
36
PIP
(n
=
9)
1.2
0.3
1.4:
0.4
90
Controlled-motion *tSignificantly *Not BMean
SD
sign&m
(n
=
excursions larger
recorded
at 3 weeks
than the controlled-motion
(p =
of individual
IS)
66
after operation. excursion
(p
= 0.001
and P = O.OGOI
rehpectwely.
with
Wilcoxon
signed
rank test).
0.06).
digits
suring point and the corresponding DIP and PIP joint range of motion. In this study the two tendon markers were placed on each side of the repair. The position of the measuring points thus differed from digit to digit, depending on location of the repair site. The material was therefore divided into three overlapping groups. One group consisted of 17 digits with at least one marker along the proximal phalanx and was examined for excursions produced by combined PIP and DIP joint motion. A second group consisted of 29 digits with at least one marker along the middle phalanx and was examined for excursions produced by DIP joint motion alone. In a third group of 10 digits with markers on both sides of the PIP joint, excursions due to isolated PIP joint motion could be calculated by deduction of excursions along the middle phalanx (caused by DIP motion) from excursions along the proximal phalanx (caused by combined PIP and DIP motion). There was only one digit with repair at the MP joint, and in this case the distal marker was used to measure excursions at proximal phalanx level.
The tendon excursion was then matched with the corresponding joint motion, and the amount of excursion produced for each 10 degrees of joint motion was calculated in each case. A linear relationship between joint motion and tendon excursion was assumed.30. 3’ If tendon excursions during active motion are defined as the optimal (largest) achievable in the individual digit, the effectiveness of the controlled-motion program can be assessed. Therefore excursions per 10 degrees of controlled motion (3 weeks after operation) were also expressed as a percentage of excursions subsequently recorded per 10 degrees of active motion (3 to 6 months postoperatively) in the same digit and joint. The effect of joint motion on the size of tendon excursions occurring during controlled motion was further evaluated by a regression analysis with range of motion as the independent value (along the x-axis). Mean excursions per 10 degrees of joint motion at the middle and proximal phalanx level were also examined in relation to the severity of the injury (i.e., single [FDP] or double [FDP + FDS] tendon injury),
The Journal of HAND SURGERY
126 Silfverskitild et al.
y = 0.05~ - 0.52.r-sqd= 0.65
0
IO
20
30
40
50
60
‘0
ROM DIP 3 weeks (degrees)
y a 0.14~ - 0.71,r-sqd- 0.85 Is
14- y =0.09x - 1.02,r-sqd10.63 12.
lo
E & ii
01 0
B
IO
20
30
40
50
60
70
80
ROM PIP 3 weeks (degrees)
C
ROM DIP + PIP 3 weeks (degrees)
Fig. 2. The relationshipbetween controlled range of motion (ROM) and the correspondingtendon excursion (TE) 3 weeks after operation. Coinciding values are indicated by larger circles with the number of digits within. A, DIP joint: n = 29, r = 0.81, p = 0.0001. B, PIP joint: n = 10, r = 0.92, p = 0.0001. C, DIP + PIP joints: n = 17, r = 0.79, p = 0.0002.
the timing of the repair (primary or delayed), and the position of the repair site (i.e., whether the excursion was measured at the same level as the repair). The effect of controlled motion excursions on the formation of adhesions and final clinical results was evaluated by plotting excursions at 3 weeks against active range of motion 6 weeks and 1 year after operation for each of the corresponding joints (in this case, with tendon excursion as the independent value). Active range of motion 6 weeks after operation (i.e., after 2 weeks of unresistive active exercises) was considered a suitable indicator of adhesion formation because it gave the patient time to reestablish normal active muscle function while not allowing adhesions of clinical relevance enough time to be significantly affected. Statistical methods included, apart from regression analysis, the Wilcoxon signed-rank test for paired sam-
ples and the Mann-Whitney U test for unpaired samples. A p value of 0.05 or less was considered to indicate a significant difference or relationship. ReSUItS
Mean tendon excursions during controlled motion at 1 and 3 weeks after operation, the corresponding joint motion, and excursions per 10 degrees of joint motion are shown in Table II. Mean active-motion excursions and the controlled/ active-motion excursion ratios are shown in Table III. There was a highly significant positive correlation between controlled joint range of motion and the corresponding tendon excursion 3 weeks after operation for both IP joints, considered separately and together (Fig. 2). There were eight cases with a DIP joint range of motion of only 10 to 15 degrees (Fig. 2, A). In seven
Vol. 17A, No. 1 January I992
Flexor digitorum profundus tendon excursions
127
?'ij g go 60, y-5.96x + 21.6.r-aqd= 0.13
g
70.
3
60.
$
s0a
0
.5
0 A
0
1
1.5
0
2
2.5
3
3.5
TE middle phalanx 3 weeks (mm)
200- y = 6.64x + 30.15,r-aqd- 0.66 160. 160. 140. 120. loo. 60. 60. m 20.0 ot
0
B
2
4
6
6
0
10
PIP induced TE 3 weeks (mm)
c
2
4
6
6
10
12
14
TE proximal phalanx 3 weeks (mm)
Fig. 3. The relationship between tendon excursion during controlled motion (TE) 3 weeks after operation and subsequent active range of motion (ROM) in the corresponding joint or joints 6 weeks after operation. A, DIP joint: n = 25, r = 0.37, p = 0.07. B, PIP joint: n = 9, r = 0.83, p = 0.006. C, DIP + PIP joints: n = 14, r = 0.93, p = 0.0001.
of these the corresponding tendon excursion was recorded as zero, and in the remaining case it was recorded as 0.5 mm. Fifteen degrees thus seemed to he an approximate threshold value below which little or no FDP excursion could be expected. Excluding these eight cases did not significantly change the mean excursion, the efficiency ratio, or the p and r values for the correlation. Although there was no obvious sign of a threshold value for PIP or combined IP joint motion, the intercept of the regression line on the y-axis lay below zero in both these groups, which could indicate the existence of a similar threshold value. There was no significant difference with respect to the distribution of cases at proximal and middle phalanx levels or the size of excursions at each level, as related to single or double tendon injuries or the timing and position of the repair. However, the number of cases
was too small for a statistical analysis with enough power to draw any definite conclusions. The relationship between controlled-motion excursions (3 weeks postoperatively) and subsequent active joint range of motion is shown in Figs. 3 and 4. The mean and standard deviation values for active range of motion 1 year after operation was 50 t 23 degrees for the DIP joint, 86 + 19 degrees for the PIP joint, and 136 + 35 degrees for both joints combined. Results classified according to Strickland’s original grading system3 were as follows: Excellent- 14 (38.8%); good- 11 (30.6%); fair-6 (16.7%); poor4 (11.1%); rupture-l (2.8%). Discussion There are not many data from previous in vivo studies with which to compare our results. Stricklandz6 used
128
The Journal of HAND SURGERY
Siffverskiiild et al.
90- ~~3.7~ + 46.27,r-sqd= 0.02 E
0
g
ii.
%
0
0
0
0
50.
g
401%
a
30.
k
0
0
20.
.s 2
10.
3 O
0
0 00
0
s
1
1.5
2
2.5
3
3.5
A
TE middle phalanx 3 weeks (mm) 120.
3 8
110.
8
100.
200- y-7.13x + 61.46,r-sqd= 0.32
y = 3.26x + 57.67,r-sqd- 0.39
160. 160. 0
ti
90.
140.
Q) ).
80.
120.
f
70.
100.
8
60.
60.
E L
50.
60.
Q)
40
40. 0
f!
30
1
201 0
0
20,
.
2
4
6
6
0, 0
10
2
4
6
6
10
12
14
C
B PIP induced TE 3 weeks (mm)
TE proximal phalanx 3 weeks (mm)
Fig. 4. The relationship between tendon excursion during controlled motion (TE) 3 weeks after operation and active range of motion (ROM) in the corresponding joint or joints 1 year after operation. A, DIP joint: n = 26, r = 0.16, p = 0.4. B, PIP joint: n = 8, r = 0.63, p = 0.1. C, DIP + PIP joints: n = 15, r = 0.56, p = 0.03.
techniques similar to ours and recorded excursions of 5 to 8 mm in “several cases” of zone II repairs treated with passive motion. The exact level and the corresponding joint motion were not defined, but the results are in accordance with ours at the proximal phalanx level (5.6 mm). Briiser and GriibmeyeP5 found mean excursions of 2.5 mm at the middle phalanx (1 mm in our material) and 7.4 mm at the proximal phalanx level in 12 patients treated with dynamic traction. A greater IP joint range of motion and a higher percentage of larger digits (fewer small fingers), factors not reported in the study, could explain the greater excursions. Studies of tendon excursions on undamaged tendons in cadaver hands have provided information on the rel-
ative merits of different splintsz3 and of excursions produced by motion in different joints under idealized conditions similar to those found in active motion. 14-‘8* z’s24*31 These results cannot, however, automatically be assumed to reflect the true effects of passive or semipassive (dynamic traction) motion in the clinical situation. In passive flexion the tendon is pushed proximally by the flexing joint. The resulting tendon excursion depends on the resistance encountered by the advancing tendon and the amount of bunching up allowed by the surrounding tissues. Such factors as bulging of the repair, postoperative edema, and fibrinous deposits could inhibit the excursion of the repaired tendon. Therefore it may not correspond to the amount
Vol. 17A, No. 1 January 1992
of joint flexion produced by an external force. Studies by Lane et a1.32support the significance of such effects. In a controlled study on rats, they showed that work of flexion increased and tendon excursions decreased significantly (compared to sham-operated animals) within 8 hours and remained decreased for 1 to 2 weeks after insertion of sutures in undamaged flexor tendons. Gap formation and contracture of the repair site are other factors that could influence tendon excursions during controlled motion in the clinical situation. (Because of their specific relevance to controlled-motion excursions and subsequent clinical results, they will be analyzed separately in a forthcoming article.) In active motion it is the tendon, moving proximally, that pulls the joint into flexion. Excursions are therefore directly related to joint motion and are influenced only by factors that affect the moment arm, such as the size and shape of the joint and the configuration of the pulley system. 30.3’.33*34 Excursions per 10 degrees of active motion can accordingly be used as a reproducible3’ standard by which to define the greatest achievable excursion in each individual digit and joint. The mean excursions of 0.9 and 1.4 mm per 10 degrees of active DIP and PIP joint motion found in this study (Table III), reflect the difference in size of the moment arms of the two joints and are very similar to values calculated theoretically (0.9 and 1.3 mm) with the use of average moment arms reported by Brand35 (5 and 7.5 mm) and to values found empirically in cadavers. Is.)’ In controlled motion the mean excursion per 10 degrees of DIP and PIP motion was 0.3 and 1.2 mm, respectively (Tables II and III). The difference due to the size of moment arms was eliminated by examination of controlled / active-motion excursion ratios. These showed that, on average, the PIP joint mobilized the tendon almost as much as during active motion (90%) and much more efficiently than the DIP joint did (36%). Explanations for the discrepancy between the joints include the possibility that the flexing PIP joint acts as a block, which, in combination with a relative slack in the sheath at the A3 and C2 pulley level (allowing more bunching up of the tendon), could impede excursions initiated by the flexing DIP joint. Previous studies of excursions in cadavers have confirmed a linear or close to linear relationship between joint motion and tendon excursions in the finger.30v3’ The results of our study show that there is also a significant positive correlation between the two during controlled motion in the clinical setting (Fig. 2). They also indicate that a linear relationship is at least a good approximation. This means we can predict that an increased controlled range of motion in either the DIP or
Flexor digitorum profundus tendon excursions
129
PIP joints (or both) will usually result in a proportionally larger FDP excursion. The rationale for increasing controlled range of motion also rests on the assumption that larger excursions will result in less adhesion formation and better clinical results.‘. “. 3744Our findings show that this is true for the PIP joint but not for the DIP joint (Fig. 3). Our indicator for assessing adhesion formation, active range of motion 6 weeks after operation, was of course an indirect one. We cannot rule out the possibility that factors with a negative effect on active range of motion (e.g., passive stiffness and gap formation) together with the fact that DIP-related excursions were small, could either have eliminated a significant relationship for the DIP joint or made it more difficult to statistically confirm such a relationship. (They obviously did not affect results enough to prevent a significant positive correlation for the PIP joint and both IP joints combined.) However, none of these possibilities would have altered the fact that FDP excursions induced by controlled DIP joint motion (equivalent to differential gliding between the FDP and FDS) never exceeded 3 mm and in 80% of the cases examined at 6 weeks did not exceed 1.5 mm and that, despite this, 40% of the cases had an active DIP joint motion of 30 degrees or more 6 weeks postoperatively (Fig. 3, A). Furthermore, 90% of the cases later regained an active DIP motion of at least 40 degrees (Fig. 4, A). The degree of differential gliding was thus small and had little influence on subsequent active DIP range of motion at 6 weeks or 1 year after operation. Our findings differ from those of Duran and Houser,’ who have stated that 3 to 5 mm of differential gliding between the FDP and FDS is desirable to prevent firm adhesions. One explanation may be that the intermittent application of stress during the controlled-motion exercises was sufficient in itself to modify scar and adhesion formation without actually producing much excursion.’ PIP-related excursions, on the other hand, did have a strong influence on adhesion formation and subsequent active range of motion. The nonsignificant p value (0.1) for isolated PIP joint motion 1 year after operation (Fig. 4, B) was probably due to the small number of cases (n = 8). It is otherwise difficult to explain the significant relationship between combined IP joint motion and controlled-motion excursions along the proximal phalanx (Fig. 4, C) when it has already been shown that these were mainly produced by PIP joint motion. The decrease in the influence of controlled-motion excursions on subsequent active range of motion that occurred between 6 weeks and 1 year after operation
130
Silfierskiiild et al,
reflects variations between individuals in such factors as age, sex, vocation, the digit injured, and concomitant nerve injuries, all of which may have influenced the patient’s motivation, ability, and opportunity to use and exercise the injured digit. Despite such secondary effects, final total active IP joint motion was significantly affected by the magnitude of tendon excursions along the proximal phalanx during the controlled-motion period. Summary and conclusions Early controlled motion with passive flexion of the PIP joint is an efficient method for producing FDP tendon excursions after repairs in zone II. On average, excursions amounted to 90% of the corresponding excursions subsequently recorded during active motion. Controlled motion in the DIP joint was much less efficient, with a controlled/ active-motion excursion ratio of 36%. Controlled range of motion in both joints did, however;. have a significant influence on the size of the resulting ‘excursions. Subsequent active range of motion in the PIP joint and both IP joints combined was also significantIy influenced by the size of excursions recorded along the proximal phalanx during controlled motion, while active DIP joint motion was not significantly influenced by DIP-induced excursions along the middle phalanx. The improved clinical end result that we can expect from an increased controlled range of motion will therefore be related primarily to the effect on the PIP joint. The results of this study also show that dynamic flexion traction (with or without a palmar pulley) will produce a limited controlled range of motion (discussed in detail in a previous article2*). We are therefore now evaluating, by the methods presented here, a new controlled-motion program designed to maximize IP joint motion within the splint. REFERENCES Duran RJ, Houser RG. Controlled passive motion following flexor tendon repair in zones 2 and 3. In: AAOS symposium on tendon surgery in the hand. St. Louis: CV Mosby, 197510514. Lister GD, Kleinert HE, Kutz JE, Atasoy E. Primary flexor tendon repair followed by immediate controlled mobilization. J HANDSURG 1977;2:44 l-5 1. Strickland JW, Glogovac SV. Digital function following flexor tendon repair in zone II: a comparison of immobilization and controlled passive motion techniques. J HANDSURG 1980;5:537-43. Ejesk%rA. Flexor tendon repair in no-man’s_land: results of primary repair with controlled mobilization. J HAND SURG 1984;9A:171-7.
The Journal of HAND SURGERY
5. Nielsen AB, Jensen PG. Primary flexor tendon repair in “no man’s land.” J HANDSURG 1984;9B:279-81. 6. Langlais F, Gibon Y, Canciani JP, Thomine JM. Primary repair of flexor tendon in zone II (103 digits): results and limitations of Kleinert’s method. Ann Chir Main 1986;5:301-14. 7. Chow JA, Thomes LJ, Dovelle S, Milnor WH, Seyfer AE, Smith AC. A combined regimen of controlled motion following flexor tendon repair in “no man’s land.” Plast Reconstr Surg 1987;79:447-53. 8. Tropet Y, Menez D, Dreyfus-Schmidt G, Vichard P. Recent simple flexor tendon injuries in zone I, II, III of Verdan: results of tendon repairs concerning 115 fingers in 99 patients. Ann Chir Main 1988;7:109-14. 9. Weeks PM, Wray RC. Management of acute hand injuries. 2nd ed. St. Louis: CV Mosby, 1978:76-108. 10. Gelberman RH, Woo SLY, Lothringer K, Akeson WH, Amiel D. Effects of early intermittent passive mobilization on healing canine flexor tendons. J HAND SURG 1982;7: 170-4. 11. Gelberman RH, Vandeberg JS, Lundborg GN, Akeson WI-I. Flexor tendon healing and restoration of the gliding surface. J Bone Joint Surg 1983;65A:70-80. 12. Hitchcock TF, Light TR, Bunch WH, et al. The effect of immediate constrained digital motion on the strength of flexor tendon repairs in chickens. J HAND SURG 1987;12A:590-5. 13. Feehan LM, Beauchene JG. Early tensile properties of healing chicken flexor tendons: early controlled passive motion versus postoperative immobilization. J HAND SURG 1990;15A:63-8. 14. Verdan C. Practical consideration for primary and secondary repair in flexor tendon injuries. Surg Clin North Am 1964;44:951-70. 15. Boyes JH, ed. Bunnell’s surgery of the hand. Philadelphia: JB Lippincott, 1964: 12-5. 16. Kaplan EB. Anatomy and kinesiology of the hand. In: Fly~ JE. Hand surgery. Baltimore: Williams &Wilkins, 1966:l l-28. 17. Simmons BP, De La Caffiniere JY. Physiology of flexion of the fingers. In: Tubiana R, ed. The hand, Vol 1. Philadelphia: WB Saunders, 1981:377-88. 18. McGrouther DA, Ahmed MR. Flexor tendon excursions in “no man’s land.” Hand 1981;13:129-41. 19. Wehbe MA, Hunter JM. Flexor tendon gliding in the hand. Part 1. In vivo excursions. J HAND SURG 1985;10A:570-4. 20. Wehbe MA, Hunter JM. Flexor tendon gliding in the hand. Part II. Differential gliding. J HAND SURG 1985;10A:575-9. 21. Schmidt HM, Lanz U. The gliding amplitudes of the flexor and extensor tendons of the fingers of the human hand. Handchirurgie 1985;17:307-13. 22. Gelberman RH, Botte MJ, Spiegelman JJ, Akeson WH. The excursion and deformation of repaired flexor tendons treated with protected early motion. J HAND SURG 1986;11A:106-10.
Vol. 17A. No. I January 1992
23. Cooney WP, Lin GT, An KN. Improved tendon excursion following flexor tendon repair. J Hand Ther 1989;2: 102-6. 24. Horibe S, Woo SLY, Spiegelman JJ, Marcin JP, Gelberman RH. Excursion of the flexor digitorum profundus tendon: a kinematic study of the human and canine digits. J Orthop Res 1990;8:167-74. 25. Briiser P. Grtibmeyer H. Gleitamplitudenmessungen bei der dynamischen Beugesehnenbehandlung. Handchirurgie 1981;13:189-91. 26. Strickland JW. Biological rationale, clinical application and results of early motion following flexor tendon repair. J Hand Ther 1989;2:71-83. 27. Ejesklr A, lrstam L. Elongation in profundus tendon repair. Stand J Plast Reconstr Surg 1981;15:61-8. 28. May EJ, Silfverskiold KL. A new power source in dynamic splinting: clinical experience and results. J Hand Ther 1989;2: 169-74. 29. McGrouther DA, Burke FD, Smith PJ. Principles of hand surgery. London: Churchill Livingstone, 1990:93-l 13. 30. Armstrong TJ, Chaffin DB. An investigation of the relationship between displacements of the finger and wrist joints and the extrinsic finger flexor tendons. J Biomech 1978;l I:1 19-28. 3 1. An KN, Ueba Y, Chao EY, Cooney WP, Linscheid RL. Tendon excursion and moment arm of index finger muscles. J Biomech 1983;16:419-2.5. 32. Lane JM, Black J, Bora FW. Gliding function following flexor tendon injury. J Bone Joint Surg 1976;58A:98590. 33. Landsmeer JMF. Studies in the anatomy of articulation. Acta Morph01 Neerl Stand 1960;3:287-303.
Flexor digitorum profundus tendon excursiorts
131
34. Brand PW. Cranor KC, Ellis JC. Tendon and pulleys at the metacarpophalangeal joint of a finger. J Bone Joint Surg 1975;57A:779-84. 35. Brand PW. Clinical mechanics of the hand. St. Louis: CV Mosby, 1985:257-9. 36. Manske PR. Flexor tendon healing. J HAND SURC 1988;13B:237-45. 37. Becker H, Hardy M. A constant tension dynamic splint. Plast Reconstr Surg 1980;66: 148-50. 38. Lopez MS, Hanley KF. Splint modifications for flexor tendon repairs. Am J Occup Ther 1984;38:398-403. 39. Edinburg M, Widgerow AD. Biddulph SL. Early postoperative mobilization of flexor tendon injuries using a modification of the Kleinert technique. J HAND SURG 1987;12A:34-8. 40. McLean NR. Some observations on controlled mobilization following flexor tendon injury. J HAND SURC 1987;128:101-4. 41. Knight SL. A modification of the Kleinert splint for mobilization of digital flexor tendons. J HAND SLJRG 1987;12B:179-81. 42. Slattery PG. A modified Kleinert splint in zone II flexor tendon injuries. J HAND SURG 1984;9B:217-8. 43. May EJ, Silfverskiold KL. A new power source in dynamic splinting: experimental studies. J Hand Ther 1989;2: 164-8. 44. Werntz JR, Chesher SP. Breidenbach WC, Kleinert HE, Bissonnette MA. A new dynamic splint for postoperative treatment of flexor tendon injury. J HAND SZJRG 1989:14A:559-66.
tendon excursions
during controlled motion after flexor tendon repair in zone II: A prospective
clinical study
Intratendinous metal markers were used to study flexor digitorum profundus tendon excursions during early controlled motion with dynamic flexion traction and to evaluate their significance for results after flexor tendon repair in zone II. The mean excursion was 1 mm along the middle phalanx and 5.6 mm along the proximal phalanx. This corresponded to a mean excursion per 10 degrees of controlled distal and proximal interphalangeal joint motion of 0.3 and 1.2 mm, respectively. Compared to active motion, controlled motion of the distal interphalangeal joint mobilized the tendon with an efficiency of 36% and controlled motion of the proximal interphalangeal joint mobilized the tendon with an efficiency of 90%. Controlled-motion excursions induced by the distal interphalangeal joint along the middle phalanx had little influence on subsequent active range of motion in the distal interphalangeal joint, whereas excursions along the proximal phalanx (for which the proximal interphalangeal joint was largely responsible) did have a significant influence on subsequent total active interphalangeal range of motion. (J HAND SURC 1992;17A:122-31.)
K. L. Silfverskiold, MD, E. J. May, BAppSc (OT), and A. H. Tiirnvall, Gothenburg, Sweden
A
dhesions and gap formation are considered the two major causes of poor results after flexor tendon repair in the hand. The various modifications of early controlled-motion programs in use today are designed to overcome these problems by promoting the excursion of repaired tendons without placing too much tension on the repair. There are many reports of improved clinical results with early controlled motion,‘-* and experimental studies in animals have confirmed a beneficial effect on the
From the Division of Hand Surgery, Department of orthopedic Surgery, and the Department of Diagnostic Radiology, Sahlgren Hospital, University of Gothenburg. The study was supported by grants from the Goteborg Medical Society, the Swedish Medical Society, the University of Gothenburg, the Greta and Einar Asker Foundation, and the Bertha and Felix Neubergh Foundation. Received for publication Sept. 11, 1990; accepted in revised form May 10, 1991. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: K. L. Silfverskiold, MD, Division of Hand Surgery, Department of Orthopaedic Surgery, Sahlgren Hospital, University of Gothenburg, 413 45 Gothenburg, Sweden. 3/l/31543 122
THE JOURNAL OF HAND SURGERY
MD,
repair process itself, including an increase in tensile strength and a decrease in adhesion formation.‘-‘3 The magnitude of tendon excursions occurring during controlled motion and their significance for clinical results are not clear, however. Although many authors have studied tendon excursions in a variety of experimental situations,‘4-24reports on tendon excursions in patients with flexor tendon repairs are few and are based on small or undefined groups of patients.25*26Studies linking tendon excursions during controlled motion with clinical results have not been reported to our knowledge. In this study we used a modification of a previously described method,‘*’ 27 incorporating intratendinous metal markers and x-ray examination techniques to study flexor digitorum profundus (FDP) tendon excursions in patients with flexor tendon repairs in zone II. We sought to answer the following questions: (1) How much does a repaired FDP tendon move during controlled motion with dynamic flexion traction? (2) What is the relationship between controlled joint range of motion and the corresponding tendon excursion? (3) How do controlled-motion excursions relate to those that occur during active motion? (4) What is the significance of controlled-motion excursions for adhesion formation and subsequent clinical results in terms of active range of motion?
Vol. 17A, No. 1 January 1992
Material From May 1987 to December 1988, 46 digits in 44 patients with uncomplicated complete FDP lacerations (with or without concomitant flexor digitorum superficialis lacerations) in zone II were operated on at the Hand Surgery Unit in Gothenburg, treated with dynamic flexion traction, and had metal markers implanted during the operations. Patients with associated injuries (other than digital artery and nerve injury) were not included in the study. Six of the original 46 digits were excluded-two because the patients disregarded instructions, two because the patients fell on the injured hands and ruptured the repairs, and two because of technically inadequate radiologic examinations. Another four digits completed the controlled-motion program and had adequate radiograms during this period but were then lost to followup. A total of 40 digits were thus assessed for tendon excursions during controlled motion and 36 of these for subsequent active range of motion 6 weeks and 1 year after operation. The mean age of patients was 32 years (range, 14 to 71 years, median, 30 years). Thirty digits (75%) belonged to men and 10 (25%) belonged to women. Relevant injury-related data are presented in Table I. Operative technique All operations were performed by the same group of specialist staff surgeons, using axillary blocks, loupes, and the same basic surgical techniques. The FDP was repaired with a modified Kessler technique with 4-O braided polyester and a 6-O continuous epitendinal stitch. The FDS was repaired with mattress sutures of 4-O braided polyester. The opened part of the sheath was adapted loosely over the repair. Two metal markers were placed in the FDP tendon a few millimeters proximal and distal to the core stitch. They consisted of 2 to 3 mm long segments of 5-O multifilament stainless steel suture with a knot in the middle. The knotted segment of the suture was pulled into the tendon after the suture needle was passed transversely through it. Both ends of the suture were cut flush with the sides of the tendon while the tendon was gently compressed with a smooth forceps. A third reference marker was placed between the other two by attaching a small single stitch of 5-O stainless steel to the dorsal periosteal rim of the sheath. The hand was immobilized in a dorsal plaster splint from below the elbow to the fingertips, with the wrist in approximately 30 to 45 degrees of palmar flexion, the metacarpophalangeal (MP) joints in 50 to 70 degrees of flexion, and the interphalangeal (IP) joints straight.
Flexor digitorum profundus tendon excursions
123
Table I. Injury-related data (n = 40)
Dominant hand Index finger Long finger Ring finger Small finger FDP + FDs* One digital nerve Two digital nerves Delayed operationt
No.
%
19
47.5
10
25
5 7
12.5 17.5
18 19 12 4 8
45 47.5 30 10 20
*Only complete FDP + PLX lacerations. TMore than 24 hours after injury.
Postoperative
treatment
Controlled mobilization was begun on the first to third postoperative day, using the same type of plaster of Paris splint and the joint positions described above. Ten active IP joint extension exercises were performed hourly against the flexion force of dynamic traction attached to the tip of the injured finger. Three different traction techniques, described in a previous article,28 were used. The tension was adjusted to produce as much IP joint flexion as possible without restricting the patient’s ability to achieve full extension. The patients were instructed not to actively flex any of the fingers. After 4 weeks of controlled mobilization, the splint was removed and active movements were commenced, which for another 2 weeks consisted of only unresistive flexion-extension exercises. Gentle resistive flexion exercises were commenced at 6 weeks and progressive resistive exercises, including blocking of the PIP joint (for differential gliding), after the eighth postoperative week. Full-power gripping was not allowed until 3 months postoperatively. Extension deficits were treated with dynamic Capener-type splints after the sixth postoperative week. All patients were reviewed regularly by the operating surgeon and the hand therapist (E. J. M.) who supervised all therapy. To get a full year’s undisturbed follow-up of all patients, no operative procedures to improve tendon function were performed during this time. Calculations of excursions and joint motion Tendon excursions were calculated from measurements on x-ray films obtained under standardized conditions by specially trained staff members. Each examination included one frontal view and two lateral views of the injured finger and a reference millimeter scale placed immediately adjacent to the finger in a plane level with and parallel to the repaired tendons. The initial position and orientation of the markers were
124
The Journal of HAND SURGERY
Siljiwrskitildet al.
Fig. 1. Radiographs in extension (A) and flexion (B) of a controlled-motion periosteal marker placed between two intratendinous markers.
established on films taken on the first postoperative day with the IP joints still immobilized in extension. One and 3 weeks after operation radiographs of a controlledmotion exercise were taken in extension and flexion (Fig. 1). When active movements were well established, between 3 and 6 months after the operation, a final set of radiographs during active motion was obtained in the 36 digits remaining for full follow-up. To determine excursions, we recorded the change occurring in the position of an intratendinous marker in relation to the fixed periosteal marker during flexion and extension of the digit. The movement of the marker (and, accordingly, the tendon) was assumed to occur along a linear path. Although ours was not computerized, the method for measuring excursions was thus essentially the same as the one described by Horibe et a1.24All measurements were performed with a micrometer, calibrated against the reference scale and adjusted to the nearest 0.5 mm level. The magnitude of errors due to inaccurate placement of the scale was calculated theoretically and confirmed by practical trials. A 1 cm difference in level between scale and finger involved an error of approximately 1% . A 1Sdegree discrepancy
exercise,
showing one
of angular position between scale and finger produced an error of 3.5%. During the actual examinations the errors were considerably smaller and therefore were considered negligible. The position and orientation of the markers were checked on equivalent views during the follow-up period to ensure that they remained in place. Adequate excursions during active motion also indicated that they remained within the tendon. At the final examination one marker had changed orientation on frontal views. Its exclusion did not affect subsequent calculations. IP joint motion was measured with a goniometer on the same radiographs used for recording excursions. Clinical recordings of active range of motion were performed by one of us (E. J. M.) at 6 weeks and 1 year after the operation. All measurements of joint motion were adjusted to the nearest 5-degree level. Analysis of excursions The excursion of a tendon is the sum of excursions produced by motion in each of the joints distal to the measuring point. 24.29Therefore calculations of tendon excursions in zone II must be related to both the mea-
Vol.
17A, No.
1
January 1992
Flexor
digitorum
profundus
Table II. Tendon excursions, the corresponding joint range of motion and excursions joint motion during the controlled motion period at 1 and 3 weeks after operation
Results
are expressed
technically
groups
3 weeks (n = 171
I weeh (/I = 25)
5.6 (3.5)
5.6 (3.5)
0.9 (0.7)
71
71 (29)
(31)
standard
the number
deviations
of digits
29
0.8 (0.3)
0.8 (0.3)
as means with
In each of the three
I week (n = 13)
varies
PIPi 3 weks fn = 2Y)
I (0.9)
5 (3.1)
5.5 13.8) 46
0.3 (0.2)
0.3 to.?,
1 tiwks 01 = 10)
I wek (n = 71
30 (15)
(141
125
per 10 degrees of
DIP+
DIP + PIP*
Tendon excursion (mm) Joint motion (degrees) TE / 10 degrees
tendon excursions
40
(23)
(20)
1.2 (0.3)
1.1 (0.6)
in parentheses. slightly
because
a feu
patient\
did
not attend
both examinations
or because
one of the eummations
wah
inadequate.
‘Equivalent
to cxcurs~ons
measured
at proximal
tEquivalent
to excursions
measured
at middle
SExcurwns
calculated
by deducting
middle
phalanx phalanx
phalanx
level. level.
excursion
from
proximal
Table III. The relationship
between tendon excursions per 10 degrees of joint motion)
phalanx
excursion
in ale\
during controlled
wth
markers
at both
levels.
and active motion (&millimeters
TEIIO” Controlled motion Mean DIP
+
PIP
0.8
0.4
I .2*
0.3
DIP
(n
=
22)
0.3
0.2
0 9:
0.7
36
PIP
(n
=
9)
1.2
0.3
1.4:
0.4
90
Controlled-motion *tSignificantly *Not BMean
SD
sign&m
(n
=
excursions larger
recorded
at 3 weeks
than the controlled-motion
(p =
of individual
IS)
66
after operation. excursion
(p
= 0.001
and P = O.OGOI
rehpectwely.
with
Wilcoxon
signed
rank test).
0.06).
digits
suring point and the corresponding DIP and PIP joint range of motion. In this study the two tendon markers were placed on each side of the repair. The position of the measuring points thus differed from digit to digit, depending on location of the repair site. The material was therefore divided into three overlapping groups. One group consisted of 17 digits with at least one marker along the proximal phalanx and was examined for excursions produced by combined PIP and DIP joint motion. A second group consisted of 29 digits with at least one marker along the middle phalanx and was examined for excursions produced by DIP joint motion alone. In a third group of 10 digits with markers on both sides of the PIP joint, excursions due to isolated PIP joint motion could be calculated by deduction of excursions along the middle phalanx (caused by DIP motion) from excursions along the proximal phalanx (caused by combined PIP and DIP motion). There was only one digit with repair at the MP joint, and in this case the distal marker was used to measure excursions at proximal phalanx level.
The tendon excursion was then matched with the corresponding joint motion, and the amount of excursion produced for each 10 degrees of joint motion was calculated in each case. A linear relationship between joint motion and tendon excursion was assumed.30. 3’ If tendon excursions during active motion are defined as the optimal (largest) achievable in the individual digit, the effectiveness of the controlled-motion program can be assessed. Therefore excursions per 10 degrees of controlled motion (3 weeks after operation) were also expressed as a percentage of excursions subsequently recorded per 10 degrees of active motion (3 to 6 months postoperatively) in the same digit and joint. The effect of joint motion on the size of tendon excursions occurring during controlled motion was further evaluated by a regression analysis with range of motion as the independent value (along the x-axis). Mean excursions per 10 degrees of joint motion at the middle and proximal phalanx level were also examined in relation to the severity of the injury (i.e., single [FDP] or double [FDP + FDS] tendon injury),
The Journal of HAND SURGERY
126 Silfverskitild et al.
y = 0.05~ - 0.52.r-sqd= 0.65
0
IO
20
30
40
50
60
‘0
ROM DIP 3 weeks (degrees)
y a 0.14~ - 0.71,r-sqd- 0.85 Is
14- y =0.09x - 1.02,r-sqd10.63 12.
lo
E & ii
01 0
B
IO
20
30
40
50
60
70
80
ROM PIP 3 weeks (degrees)
C
ROM DIP + PIP 3 weeks (degrees)
Fig. 2. The relationshipbetween controlled range of motion (ROM) and the correspondingtendon excursion (TE) 3 weeks after operation. Coinciding values are indicated by larger circles with the number of digits within. A, DIP joint: n = 29, r = 0.81, p = 0.0001. B, PIP joint: n = 10, r = 0.92, p = 0.0001. C, DIP + PIP joints: n = 17, r = 0.79, p = 0.0002.
the timing of the repair (primary or delayed), and the position of the repair site (i.e., whether the excursion was measured at the same level as the repair). The effect of controlled motion excursions on the formation of adhesions and final clinical results was evaluated by plotting excursions at 3 weeks against active range of motion 6 weeks and 1 year after operation for each of the corresponding joints (in this case, with tendon excursion as the independent value). Active range of motion 6 weeks after operation (i.e., after 2 weeks of unresistive active exercises) was considered a suitable indicator of adhesion formation because it gave the patient time to reestablish normal active muscle function while not allowing adhesions of clinical relevance enough time to be significantly affected. Statistical methods included, apart from regression analysis, the Wilcoxon signed-rank test for paired sam-
ples and the Mann-Whitney U test for unpaired samples. A p value of 0.05 or less was considered to indicate a significant difference or relationship. ReSUItS
Mean tendon excursions during controlled motion at 1 and 3 weeks after operation, the corresponding joint motion, and excursions per 10 degrees of joint motion are shown in Table II. Mean active-motion excursions and the controlled/ active-motion excursion ratios are shown in Table III. There was a highly significant positive correlation between controlled joint range of motion and the corresponding tendon excursion 3 weeks after operation for both IP joints, considered separately and together (Fig. 2). There were eight cases with a DIP joint range of motion of only 10 to 15 degrees (Fig. 2, A). In seven
Vol. 17A, No. 1 January I992
Flexor digitorum profundus tendon excursions
127
?'ij g go 60, y-5.96x + 21.6.r-aqd= 0.13
g
70.
3
60.
$
s0a
0
.5
0 A
0
1
1.5
0
2
2.5
3
3.5
TE middle phalanx 3 weeks (mm)
200- y = 6.64x + 30.15,r-aqd- 0.66 160. 160. 140. 120. loo. 60. 60. m 20.0 ot
0
B
2
4
6
6
0
10
PIP induced TE 3 weeks (mm)
c
2
4
6
6
10
12
14
TE proximal phalanx 3 weeks (mm)
Fig. 3. The relationship between tendon excursion during controlled motion (TE) 3 weeks after operation and subsequent active range of motion (ROM) in the corresponding joint or joints 6 weeks after operation. A, DIP joint: n = 25, r = 0.37, p = 0.07. B, PIP joint: n = 9, r = 0.83, p = 0.006. C, DIP + PIP joints: n = 14, r = 0.93, p = 0.0001.
of these the corresponding tendon excursion was recorded as zero, and in the remaining case it was recorded as 0.5 mm. Fifteen degrees thus seemed to he an approximate threshold value below which little or no FDP excursion could be expected. Excluding these eight cases did not significantly change the mean excursion, the efficiency ratio, or the p and r values for the correlation. Although there was no obvious sign of a threshold value for PIP or combined IP joint motion, the intercept of the regression line on the y-axis lay below zero in both these groups, which could indicate the existence of a similar threshold value. There was no significant difference with respect to the distribution of cases at proximal and middle phalanx levels or the size of excursions at each level, as related to single or double tendon injuries or the timing and position of the repair. However, the number of cases
was too small for a statistical analysis with enough power to draw any definite conclusions. The relationship between controlled-motion excursions (3 weeks postoperatively) and subsequent active joint range of motion is shown in Figs. 3 and 4. The mean and standard deviation values for active range of motion 1 year after operation was 50 t 23 degrees for the DIP joint, 86 + 19 degrees for the PIP joint, and 136 + 35 degrees for both joints combined. Results classified according to Strickland’s original grading system3 were as follows: Excellent- 14 (38.8%); good- 11 (30.6%); fair-6 (16.7%); poor4 (11.1%); rupture-l (2.8%). Discussion There are not many data from previous in vivo studies with which to compare our results. Stricklandz6 used
128
The Journal of HAND SURGERY
Siffverskiiild et al.
90- ~~3.7~ + 46.27,r-sqd= 0.02 E
0
g
ii.
%
0
0
0
0
50.
g
401%
a
30.
k
0
0
20.
.s 2
10.
3 O
0
0 00
0
s
1
1.5
2
2.5
3
3.5
A
TE middle phalanx 3 weeks (mm) 120.
3 8
110.
8
100.
200- y-7.13x + 61.46,r-sqd= 0.32
y = 3.26x + 57.67,r-sqd- 0.39
160. 160. 0
ti
90.
140.
Q) ).
80.
120.
f
70.
100.
8
60.
60.
E L
50.
60.
Q)
40
40. 0
f!
30
1
201 0
0
20,
.
2
4
6
6
0, 0
10
2
4
6
6
10
12
14
C
B PIP induced TE 3 weeks (mm)
TE proximal phalanx 3 weeks (mm)
Fig. 4. The relationship between tendon excursion during controlled motion (TE) 3 weeks after operation and active range of motion (ROM) in the corresponding joint or joints 1 year after operation. A, DIP joint: n = 26, r = 0.16, p = 0.4. B, PIP joint: n = 8, r = 0.63, p = 0.1. C, DIP + PIP joints: n = 15, r = 0.56, p = 0.03.
techniques similar to ours and recorded excursions of 5 to 8 mm in “several cases” of zone II repairs treated with passive motion. The exact level and the corresponding joint motion were not defined, but the results are in accordance with ours at the proximal phalanx level (5.6 mm). Briiser and GriibmeyeP5 found mean excursions of 2.5 mm at the middle phalanx (1 mm in our material) and 7.4 mm at the proximal phalanx level in 12 patients treated with dynamic traction. A greater IP joint range of motion and a higher percentage of larger digits (fewer small fingers), factors not reported in the study, could explain the greater excursions. Studies of tendon excursions on undamaged tendons in cadaver hands have provided information on the rel-
ative merits of different splintsz3 and of excursions produced by motion in different joints under idealized conditions similar to those found in active motion. 14-‘8* z’s24*31 These results cannot, however, automatically be assumed to reflect the true effects of passive or semipassive (dynamic traction) motion in the clinical situation. In passive flexion the tendon is pushed proximally by the flexing joint. The resulting tendon excursion depends on the resistance encountered by the advancing tendon and the amount of bunching up allowed by the surrounding tissues. Such factors as bulging of the repair, postoperative edema, and fibrinous deposits could inhibit the excursion of the repaired tendon. Therefore it may not correspond to the amount
Vol. 17A, No. 1 January 1992
of joint flexion produced by an external force. Studies by Lane et a1.32support the significance of such effects. In a controlled study on rats, they showed that work of flexion increased and tendon excursions decreased significantly (compared to sham-operated animals) within 8 hours and remained decreased for 1 to 2 weeks after insertion of sutures in undamaged flexor tendons. Gap formation and contracture of the repair site are other factors that could influence tendon excursions during controlled motion in the clinical situation. (Because of their specific relevance to controlled-motion excursions and subsequent clinical results, they will be analyzed separately in a forthcoming article.) In active motion it is the tendon, moving proximally, that pulls the joint into flexion. Excursions are therefore directly related to joint motion and are influenced only by factors that affect the moment arm, such as the size and shape of the joint and the configuration of the pulley system. 30.3’.33*34 Excursions per 10 degrees of active motion can accordingly be used as a reproducible3’ standard by which to define the greatest achievable excursion in each individual digit and joint. The mean excursions of 0.9 and 1.4 mm per 10 degrees of active DIP and PIP joint motion found in this study (Table III), reflect the difference in size of the moment arms of the two joints and are very similar to values calculated theoretically (0.9 and 1.3 mm) with the use of average moment arms reported by Brand35 (5 and 7.5 mm) and to values found empirically in cadavers. Is.)’ In controlled motion the mean excursion per 10 degrees of DIP and PIP motion was 0.3 and 1.2 mm, respectively (Tables II and III). The difference due to the size of moment arms was eliminated by examination of controlled / active-motion excursion ratios. These showed that, on average, the PIP joint mobilized the tendon almost as much as during active motion (90%) and much more efficiently than the DIP joint did (36%). Explanations for the discrepancy between the joints include the possibility that the flexing PIP joint acts as a block, which, in combination with a relative slack in the sheath at the A3 and C2 pulley level (allowing more bunching up of the tendon), could impede excursions initiated by the flexing DIP joint. Previous studies of excursions in cadavers have confirmed a linear or close to linear relationship between joint motion and tendon excursions in the finger.30v3’ The results of our study show that there is also a significant positive correlation between the two during controlled motion in the clinical setting (Fig. 2). They also indicate that a linear relationship is at least a good approximation. This means we can predict that an increased controlled range of motion in either the DIP or
Flexor digitorum profundus tendon excursions
129
PIP joints (or both) will usually result in a proportionally larger FDP excursion. The rationale for increasing controlled range of motion also rests on the assumption that larger excursions will result in less adhesion formation and better clinical results.‘. “. 3744Our findings show that this is true for the PIP joint but not for the DIP joint (Fig. 3). Our indicator for assessing adhesion formation, active range of motion 6 weeks after operation, was of course an indirect one. We cannot rule out the possibility that factors with a negative effect on active range of motion (e.g., passive stiffness and gap formation) together with the fact that DIP-related excursions were small, could either have eliminated a significant relationship for the DIP joint or made it more difficult to statistically confirm such a relationship. (They obviously did not affect results enough to prevent a significant positive correlation for the PIP joint and both IP joints combined.) However, none of these possibilities would have altered the fact that FDP excursions induced by controlled DIP joint motion (equivalent to differential gliding between the FDP and FDS) never exceeded 3 mm and in 80% of the cases examined at 6 weeks did not exceed 1.5 mm and that, despite this, 40% of the cases had an active DIP joint motion of 30 degrees or more 6 weeks postoperatively (Fig. 3, A). Furthermore, 90% of the cases later regained an active DIP motion of at least 40 degrees (Fig. 4, A). The degree of differential gliding was thus small and had little influence on subsequent active DIP range of motion at 6 weeks or 1 year after operation. Our findings differ from those of Duran and Houser,’ who have stated that 3 to 5 mm of differential gliding between the FDP and FDS is desirable to prevent firm adhesions. One explanation may be that the intermittent application of stress during the controlled-motion exercises was sufficient in itself to modify scar and adhesion formation without actually producing much excursion.’ PIP-related excursions, on the other hand, did have a strong influence on adhesion formation and subsequent active range of motion. The nonsignificant p value (0.1) for isolated PIP joint motion 1 year after operation (Fig. 4, B) was probably due to the small number of cases (n = 8). It is otherwise difficult to explain the significant relationship between combined IP joint motion and controlled-motion excursions along the proximal phalanx (Fig. 4, C) when it has already been shown that these were mainly produced by PIP joint motion. The decrease in the influence of controlled-motion excursions on subsequent active range of motion that occurred between 6 weeks and 1 year after operation
130
Silfierskiiild et al,
reflects variations between individuals in such factors as age, sex, vocation, the digit injured, and concomitant nerve injuries, all of which may have influenced the patient’s motivation, ability, and opportunity to use and exercise the injured digit. Despite such secondary effects, final total active IP joint motion was significantly affected by the magnitude of tendon excursions along the proximal phalanx during the controlled-motion period. Summary and conclusions Early controlled motion with passive flexion of the PIP joint is an efficient method for producing FDP tendon excursions after repairs in zone II. On average, excursions amounted to 90% of the corresponding excursions subsequently recorded during active motion. Controlled motion in the DIP joint was much less efficient, with a controlled/ active-motion excursion ratio of 36%. Controlled range of motion in both joints did, however;. have a significant influence on the size of the resulting ‘excursions. Subsequent active range of motion in the PIP joint and both IP joints combined was also significantIy influenced by the size of excursions recorded along the proximal phalanx during controlled motion, while active DIP joint motion was not significantly influenced by DIP-induced excursions along the middle phalanx. The improved clinical end result that we can expect from an increased controlled range of motion will therefore be related primarily to the effect on the PIP joint. The results of this study also show that dynamic flexion traction (with or without a palmar pulley) will produce a limited controlled range of motion (discussed in detail in a previous article2*). We are therefore now evaluating, by the methods presented here, a new controlled-motion program designed to maximize IP joint motion within the splint. REFERENCES Duran RJ, Houser RG. Controlled passive motion following flexor tendon repair in zones 2 and 3. In: AAOS symposium on tendon surgery in the hand. St. Louis: CV Mosby, 197510514. Lister GD, Kleinert HE, Kutz JE, Atasoy E. Primary flexor tendon repair followed by immediate controlled mobilization. J HANDSURG 1977;2:44 l-5 1. Strickland JW, Glogovac SV. Digital function following flexor tendon repair in zone II: a comparison of immobilization and controlled passive motion techniques. J HANDSURG 1980;5:537-43. Ejesk%rA. Flexor tendon repair in no-man’s_land: results of primary repair with controlled mobilization. J HAND SURG 1984;9A:171-7.
The Journal of HAND SURGERY
5. Nielsen AB, Jensen PG. Primary flexor tendon repair in “no man’s land.” J HANDSURG 1984;9B:279-81. 6. Langlais F, Gibon Y, Canciani JP, Thomine JM. Primary repair of flexor tendon in zone II (103 digits): results and limitations of Kleinert’s method. Ann Chir Main 1986;5:301-14. 7. Chow JA, Thomes LJ, Dovelle S, Milnor WH, Seyfer AE, Smith AC. A combined regimen of controlled motion following flexor tendon repair in “no man’s land.” Plast Reconstr Surg 1987;79:447-53. 8. Tropet Y, Menez D, Dreyfus-Schmidt G, Vichard P. Recent simple flexor tendon injuries in zone I, II, III of Verdan: results of tendon repairs concerning 115 fingers in 99 patients. Ann Chir Main 1988;7:109-14. 9. Weeks PM, Wray RC. Management of acute hand injuries. 2nd ed. St. Louis: CV Mosby, 1978:76-108. 10. Gelberman RH, Woo SLY, Lothringer K, Akeson WH, Amiel D. Effects of early intermittent passive mobilization on healing canine flexor tendons. J HAND SURG 1982;7: 170-4. 11. Gelberman RH, Vandeberg JS, Lundborg GN, Akeson WI-I. Flexor tendon healing and restoration of the gliding surface. J Bone Joint Surg 1983;65A:70-80. 12. Hitchcock TF, Light TR, Bunch WH, et al. The effect of immediate constrained digital motion on the strength of flexor tendon repairs in chickens. J HAND SURG 1987;12A:590-5. 13. Feehan LM, Beauchene JG. Early tensile properties of healing chicken flexor tendons: early controlled passive motion versus postoperative immobilization. J HAND SURG 1990;15A:63-8. 14. Verdan C. Practical consideration for primary and secondary repair in flexor tendon injuries. Surg Clin North Am 1964;44:951-70. 15. Boyes JH, ed. Bunnell’s surgery of the hand. Philadelphia: JB Lippincott, 1964: 12-5. 16. Kaplan EB. Anatomy and kinesiology of the hand. In: Fly~ JE. Hand surgery. Baltimore: Williams &Wilkins, 1966:l l-28. 17. Simmons BP, De La Caffiniere JY. Physiology of flexion of the fingers. In: Tubiana R, ed. The hand, Vol 1. Philadelphia: WB Saunders, 1981:377-88. 18. McGrouther DA, Ahmed MR. Flexor tendon excursions in “no man’s land.” Hand 1981;13:129-41. 19. Wehbe MA, Hunter JM. Flexor tendon gliding in the hand. Part 1. In vivo excursions. J HAND SURG 1985;10A:570-4. 20. Wehbe MA, Hunter JM. Flexor tendon gliding in the hand. Part II. Differential gliding. J HAND SURG 1985;10A:575-9. 21. Schmidt HM, Lanz U. The gliding amplitudes of the flexor and extensor tendons of the fingers of the human hand. Handchirurgie 1985;17:307-13. 22. Gelberman RH, Botte MJ, Spiegelman JJ, Akeson WH. The excursion and deformation of repaired flexor tendons treated with protected early motion. J HAND SURG 1986;11A:106-10.
Vol. 17A. No. I January 1992
23. Cooney WP, Lin GT, An KN. Improved tendon excursion following flexor tendon repair. J Hand Ther 1989;2: 102-6. 24. Horibe S, Woo SLY, Spiegelman JJ, Marcin JP, Gelberman RH. Excursion of the flexor digitorum profundus tendon: a kinematic study of the human and canine digits. J Orthop Res 1990;8:167-74. 25. Briiser P. Grtibmeyer H. Gleitamplitudenmessungen bei der dynamischen Beugesehnenbehandlung. Handchirurgie 1981;13:189-91. 26. Strickland JW. Biological rationale, clinical application and results of early motion following flexor tendon repair. J Hand Ther 1989;2:71-83. 27. Ejesklr A, lrstam L. Elongation in profundus tendon repair. Stand J Plast Reconstr Surg 1981;15:61-8. 28. May EJ, Silfverskiold KL. A new power source in dynamic splinting: clinical experience and results. J Hand Ther 1989;2: 169-74. 29. McGrouther DA, Burke FD, Smith PJ. Principles of hand surgery. London: Churchill Livingstone, 1990:93-l 13. 30. Armstrong TJ, Chaffin DB. An investigation of the relationship between displacements of the finger and wrist joints and the extrinsic finger flexor tendons. J Biomech 1978;l I:1 19-28. 3 1. An KN, Ueba Y, Chao EY, Cooney WP, Linscheid RL. Tendon excursion and moment arm of index finger muscles. J Biomech 1983;16:419-2.5. 32. Lane JM, Black J, Bora FW. Gliding function following flexor tendon injury. J Bone Joint Surg 1976;58A:98590. 33. Landsmeer JMF. Studies in the anatomy of articulation. Acta Morph01 Neerl Stand 1960;3:287-303.
Flexor digitorum profundus tendon excursiorts
131
34. Brand PW. Cranor KC, Ellis JC. Tendon and pulleys at the metacarpophalangeal joint of a finger. J Bone Joint Surg 1975;57A:779-84. 35. Brand PW. Clinical mechanics of the hand. St. Louis: CV Mosby, 1985:257-9. 36. Manske PR. Flexor tendon healing. J HAND SURC 1988;13B:237-45. 37. Becker H, Hardy M. A constant tension dynamic splint. Plast Reconstr Surg 1980;66: 148-50. 38. Lopez MS, Hanley KF. Splint modifications for flexor tendon repairs. Am J Occup Ther 1984;38:398-403. 39. Edinburg M, Widgerow AD. Biddulph SL. Early postoperative mobilization of flexor tendon injuries using a modification of the Kleinert technique. J HAND SURG 1987;12A:34-8. 40. McLean NR. Some observations on controlled mobilization following flexor tendon injury. J HAND SURC 1987;128:101-4. 41. Knight SL. A modification of the Kleinert splint for mobilization of digital flexor tendons. J HAND SLJRG 1987;12B:179-81. 42. Slattery PG. A modified Kleinert splint in zone II flexor tendon injuries. J HAND SURG 1984;9B:217-8. 43. May EJ, Silfverskiold KL. A new power source in dynamic splinting: experimental studies. J Hand Ther 1989;2: 164-8. 44. Werntz JR, Chesher SP. Breidenbach WC, Kleinert HE, Bissonnette MA. A new dynamic splint for postoperative treatment of flexor tendon injury. J HAND SZJRG 1989:14A:559-66.
