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Hand Surgery, Vol. 19, No. 3 (2014) 1–6 © World Scientific Publishing Company DOI: 10.1142/S0218810414500270

COMPARISON OF RADIOLOGICAL AND CLINICAL OUTCOMES OF INTERNAL FIXATION USING TWO DIFFERENT VOLAR PLATES FOR DISTAL RADIUS FRACTURES Chul-Hyun Cho,* Si-Wook Lee* and Gu-Hee Jung† *Department

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of Orthopedic Surgery, Pain Research Center Dongsan Medical Center, School of Medicine Keimyung University, Daegu, Korea

†Department

of Orthopedic Surgery, Gospel Hospital School of Medicine, Kosin University Busan, Korea

Received 28 March 2014; Revised 3 May 2014; Accepted 7 May 2014; Published 26 August 2014 ABSTRACT The purpose of this study was to compare the outcomes of volar plating using two different implants for distal radius fractures. Fifty-two patients with AO type C fractures were placed in either of two groups: the AO LDRS group (26 patients) or the Acu-Loc group (26 patients). Radiological parameters including radial length, radial inclination, volar tilt, and intra-articular step-off were significantly improved after surgery. The mean Mayo Wrist Performance Score was 84.6 in the AO LDRS group and 81.1 in the AcuLoc group. The mean Subjective Wrist Value was 86.7% in the AO LDRS group and 86.3% in the Acu-Loc group. There were no significant differences between the two groups with respect to both radiological and clinical outcomes at the final follow-up evaluation. Volar fixed-angle plating for unstable distal radius fractures had satisfactory radiological and clinical outcomes. The difference of implant design did not influence overall final outcomes. Keywords: Distal Radius Fracture; Volar Fixed-Angle Plate; Implant; Outcome.

Volar fixed-angle plating has gained widespread popularity as a new approach to the surgical treatment of unstable distal radius fractures.1 Many studies have demonstrated that volar fixed-angle plating has better radiological and clinical outcomes compared with other fixation methods.2,3,6–8 As the popularity of volar fixed-angle plating for distal radius fractures has increased, new implants have become available and the selection of implants has expanded dramatically.1,9

INTRODUCTION Distal radius fracture is the most common injury, accounting for 15% of all fractures.1 Although they can be treated nonoperatively, operative treatment is necessary in unstable distal radius fractures.2 Because open reduction and internal fixation (ORIF) allows early rehabilitation and an earlier return to activities of daily living, it has become more common to treat distal radius fractures surgically.3–5

Correspondence to: Dr. Chul-Hyun Cho, 56 Dalseong-ro, Jung-gu, Daegu 700-712, Korea. Tel: (þ82) 53-250-7729, Fax: (þ82) 53-250-7205, E-mail: [email protected] 1

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Variations in plate design include adaptations in shape and contour of the plate, the size and angle of the screws, the locking screw mechanism, and the type of plate material.10 Several biomechanical studies have demonstrated that most volar fixed-angle implants have sufficient biomechanical properties to facilitate early mobilization for unstable distal radius fractures.1,11,12 However, to our knowledge, there is no study that compares outcomes for the use of different volar fixed-angle plates for distal radius fractures. Therefore, we compared radiological and clinical outcomes after ORIF using two different implants for AO type C distal radius fractures.

Surgical Technique All operations were performed by a single surgeon using a volar approach through the flexor carpi radialis tendon sheath. The distal and radial borders of the pronator quadratus were elevated, and the volar aspect of the radius was exposed subperiosteally. The plate was placed directly on the radius after reduction of the fracture, and the adequacy of plate and screw positioning was confirmed during surgery by fluoroscopy. The pronator quadratus was repaired to protect the flexor tendons. All patients were immobilized by short arm splint and started physiotherapy at two weeks after surgery.

Radiological and Clinical Assessment Hand Surg. Downloaded from www.worldscientific.com by UNIVERSITY OF BERN on 09/16/14. For personal use only.

MATERIALS AND METHODS This retrospective study was approved by our institutional review board. Between December 2009 and May 2012, 52 patients undergoing ORIF using volar fixed-angle plates for AO type C distal radius fractures were enrolled with prospective data collection. Patients were placed in either of two groups, the AO LDRS(Synthes, Paoli, PA, USA) group (26 patients) or the AcuLoc(Acumed, Hillsboro, OR, USA) group (26 patients), according to whether the last digit of their hospital case number was even or odd. Indications for ORIF included radial length of < 10 mm, radial inclination of < 15  , dorsal angulation of > 10  , or intra-articular step-off of  2 mm. Exclusion criteria were (1) age < 20 years, (2) concomitant upper extremity injuries, and (3) AO type A and B fractures. The mean age of the patients was 57.9 years (range, 28–79 years), and there were 17 men (32.7%) and 35 women (67.3%). In 25 patients (48.1%), the fracture was in the dominant arm. The mean interval from initial trauma to operation was 5.5 days (range, 0–21 days). Injury mechanism was classified into either of two energy grades, with fall from heights of > 1.5 m, motor vehicle accidents, and sports injuries defined as high-energy trauma and all other injuries defined as low-energy trauma. There were 10 patients (19.2%) in the high-energy trauma group and 42 (80.8%) in the low-energy trauma group. Thirty-five patients (67.3%) had ulnar fractures, including fractures of the metaphysis or styloid process, and 13 patients (25.0%) had an associated injury beyond the affected wrist. Twelve patients (23.1%) had an AO type C1 fracture, 13 (25.0%) had AO type C2, and 27 (51.9%) had AO type C3. The mean duration of follow-up was 33.5 months (range, 12–42 months).

Radiological outcomes were evaluated by plain radiographs before surgery, after surgery, and at the final follow-up examination. Radiological parameters included radial length, radial inclination, volar tilt, and intra-articular step-off. Clinical outcomes were evaluated by Mayo Wrist Performance Score (MWPS) 13 and Subjective Wrist Value (SWV) at the final follow-up examination. The SWV is defined as a patient’s subjective wrist assessment expressed as a percentage of the score for an entirely normal wrist, which would score 100%. Post-operative complications were also assessed.

Statistical Analysis Statistical analysis was performed using SPSS software (version 15.0E; IBM, Armonk, NY, USA). To compare radiological and clinical outcomes between the two groups, we used the MannWhitney U test and the chi-square test. To determine the correlation between clinical outcomes and various parameters, we used the Spearman correlation test, Mann-Whitney U test, and Kruskal-Wallis test. Statistical significance was set at a p value of < 0.05.

RESULTS No statistically significant difference was found between the two groups with regard to age, sex, involved side, injury mechanism, interval from initial trauma to operation, ulnar fracture, associated injury, or type of fracture (Table 1). All patients had bony union within three months after surgery. Radiological parameters, including radial length, radial inclination, volar tilt, and intra-articular step-off, were significantly improved after surgery in both groups ( p < 0:001). The

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Comparison of Radiological and Clinical Outcomes of Internal Fixation

Table 1

Demographic Data.

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Age Sex (man:woman) Involved side (dominant:nondominant) Injury mechanism (high energy:low energy) Interval from initial trauma to operation Ulnar fracture Associated injury Type of fracture (AO) C1/C2/C3

Table 3 Comparison of Clinical Outcomes Between the Two Groups.

AO LDRS Group

Acu-Loc Group

p

55.5 10:16 9:17

60.2 7:19 16:10

0.097 0.555 0.095

6:20

4:22

0.726

4.9

6.0

0.169

20 5

15 8

0.237 0.523 0.614

5/7/14

7/6/13

Radiological Parameters

mean radial length at the final follow-up examination was 12:5  2:5 mm for the AO LDRS group and 11:4  2:5 mm for the Acu-Loc group. The respective values for the two groups for mean radial inclination, mean volar tilt, and mean intraarticular step-off were 26:2  2:7  and 26:4  4:2  , 6:4  9:6  and 6:5  8:7  , and 0:2  0:7 mm and 0:0  0:2 mm. There were no significant differences between the two groups with respect to any radiological parameters ( p > 0:05) (Table 2). Table 2 Groups.

Comparison of Radiological Results Between the Two

Radiological Parameters Radial length (mm) Pre-operative Post-operative Final follow-up Radial inclination (  ) Pre-operative Post-operative Final follow-up Volar tilt (  ) Pre-operative Post-operative Final follow-up Intra-articular step-off (mm) Pre-operative Post-operative Final follow-up

3

AO LDRS Group

Acu-Loc Group

p

9.9  4.2 13.1  2.1 12.5  2.5

7.4  5.4 11.9  2.8 11.4  2.5

0.146

22.7  4.4 26.6  2.3 26.2  2.7

22.2  6.3 26.6  3.9 26.4  4.2

8.3  14.0 6.7  9.3 6.4  9.6

13.5  14.4 7.7  5.5 6.5  8.7

0.728

0.7  1.1 0.2  0.6 0.2  0.7

0.2  0.6 0.0  0.2 0.0  0.2

0.163

Mayo Wrist Performance Score Excellent Good Fair Poor Subjective Wrist Value (%)

AO LDRS Group

Acu-Loc Group

84.6  17.6 12 7 6 1 86.7  15.9

81.1  20.4 11 7 5 3 86.3  18.1

p 0.163

0.886

In the AO LDRS group, the mean MWPS at the final followup evaluation was 84:6  17:6, with scores being excellent in 12 patients, good in seven, fair in six, and poor in one patient. In the Acu-Loc group, the mean MWPS was 81:1  20:4, with scores being excellent in 11, good in seven, fair in five, and poor in three. The mean SWV at the final follow-up examination was 86:7  15:9% in the AO LDRS group and 86:3  18:1% in the Acu-Loc group. There were no significant differences between the two groups with respect to clinical outcomes ( p > 0:05) (Table 3). The pre-operative parameters, including age, sex, involved side, injury mechanism, interval from initial trauma to operation, ulnar fracture, associated injury, and type of fracture, did not correlate with the MWPS and SWV at the final follow-up evaluation ( p > 0:05) (Table 4). In the AO LDRS group, three patients (11.5%) had postoperative complications: two had malunion and one had a permanent ulnar nerve injury. In the Acu-Loc group, four patients (15.4%) had post-operative complications: one had malunion, one had a temporary ulnar nerve injury, one had a complex regional pain syndrome, and one had flexor tendinitis. There were no significant differences between the

Table 4 Correlation Between Clinical Outcomes and Various Parameters. 0.654

Parameters Age Sex Involved side Injury mechanism Ulnar fracture Associated injury Type of fracture (AO)

Mayo Wrist Performance Score

Subjective Wrist Value

0.143 0.283 0.866 0.562 0.426 0.666 0.903

0.986 0.157 0.894 0.417 0.752 0.651 0.783

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Table 5 Comparison of Post-Operative Complications Between the Two Groups.

Radiological Parameters Post-operative Complications (number of cases) Malunion Temporal ulnar nerve injury Permanent ulnar nerve injury Complex regional pain syndrome Flexor tendinitis

AO LDRS Group

Acu-Loc Group

p

3

4

1.00

2 0 1 0 0

1 1 0 1 1

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two groups with respect to post-operative complications ( p > 0:05) (Table 5).

DISCUSSION The present study revealed that outcomes for volar fixed-angle plating for unstable distal radius fractures are satisfactory and that the difference in implant design does not influence the overall final outcome. These radiological and clinical results are consistent with those of previous cohort studies of unstable distal radius fractures treated with open reduction and plate fixation.4,9,14–16 The complication rates in this study are also similar to those of previous reports for volar fixed-angle plating.5,8,10,15,17,18 Numerous fixation methods including Kirschner wires, screws, intramedullary nails, external fixators, and plates, have been proposed for treating distal radius fractures.2,3,6–8 Recently, open reduction and plate fixation has been in the limelight because it allows early joint motion and an earlier return to activities of daily living.3–5 Several prospective randomized studies have demonstrated that plate fixation has better radiological and clinical outcomes and a decreased incidence of complications compared with other fixation methods such as Kirschner wires, intramedullary nails, and external fixators.3,4,6 Although volar plating, dorsal plating, and fragmentspecific plating are available, the use of volar fixed-angle plates in the elderly has been increasing because the plates provide better reduction and stability and allow early mobilization.2,16 Moreover, this technique reports a lower risk of tendinous damage compared with dorsal plating because of plate coverage by the pronator quadratus.3 In fact, the volar fixed-angle plating showed advantages over dorsal plating and over

fragment-specific plating in the fixation of unstable distal radius fractures.2,14 Stevenson et al.16 reported that in 33 patients, displaced distal radius fractures were treated with the use of volar locking plates. Their results confirmed that ORIF using a locking plate is a suitable method for accurately reducing and maintaining the position of the majority of distal radius fractures, facilitating early mobilization and functional recovery. In our study, 37 of 52 patients (71.1%) had satisfactory outcomes after volar fixed-angle plating for AO type C distal radius fractures after a mean follow-up period of 33.5 months. Our results are comparable to the final clinical and radiological outcomes presented in these recent studies.4,9,14–16 A major of volar fixed-angle plates are precontoured to provide a low-profile device that facilitates application, serves as a template for reduction, and rests in the concavity of the volar distal radius in an effort to avoid soft tissue complications.1 There are numerous volar plating systems available for treating distal radius fractures. Biomechanical studies have demonstrated the stability of plating with early mobilization for extraarticular fractures or for AO type C2 fractures.1,11 Kamei et al.12 reported a biomechanical study in a cadaveric model of the stability of volar locking plating systems for AO type C3 distal radius fractures. They noted that all of the five volar plating systems provided sufficient stability to permit 3000 repeated motions of the digits after surgery.12 Several researchers have reported that internal fixation using volar fixed-angle plates has satisfactory radiological and clinical outcomes.9,14–16 In addition, several experimental studies have compared the biomechanical properties of various

Fig. 1

Acu-Loc plate.

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(A)

5

(B)

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Fig. 2 AO LDRS plates: (A) extra-articular plate and (B) juxta-articular plate.

volar fixed-angle plating systems.1,11,12 However, our study is the first direct comparison of the radiological and clinical outcomes of internal fixation using two different volar fixedangle implants for AO type C fractures. Acu-Loc plates have two rows of screws and two radial styloid screws (Fig. 1). The screws in the distal row are oriented perpendicularly or slightly proximal, whereas those in the proximal row are oriented distally.1 This configuration theoretically provides more stability to protect against distal fragment collapse.1,14 It fits best at the watershed line, which pushes the theoretical limit set by the surrounding soft tissues.1 AO LDRS plates are available in two designs: juxta-articular and extraarticular (Fig. 2). They have a single row of distal screws. The AO juxta-articular plate is the only plate that fits best at a point distal to the watershed line, which makes it more prominent than the other plates.1 The proposed benefits are (1) the additional stabilization that it provides for the volar lunate fragment in fractures with intra-articular comminution, and (2) that it allows for some minor contouring to improve fit.1 Dahl et al.11 reported that all plate constructs met the anticipated demands with sufficient biomechanical properties. They emphasized that fracture configuration, screw placement, cost, and surgeon familiarity with instrumentation should take priority in the selection of a plating system for distal radius fractures.11 We also used Acu-Loc and AO LDRS plates for our study because these plate are most commonly used in our country. In this study, radiological parameters including radial length, radial inclination, volar tilt, and intra-articular step-off,

were significantly improved for both groups after surgery without significant loss of reduction by the final follow-up evaluation, and there were no statistically significant differences between groups for any of those parameters. Regarding clinical results, 19 patients (73.1%) in our AO LDRS group and 18 patients (69.2%) in our Acu-Loc group had satisfactory outcomes, not a statistically significant difference. These findings are consistent with the radiological and clinical outcomes of previous studies.10,14 Recent studies have reported complication rates from 5.7% to 27% after volar plating, with complications including tendon injuries, tendinitis, carpal tunnel syndrome, nerve injuries, complex regional pain syndrome, malunion, and intra-articular screw displacement.5,8,10,15,17,18 Our complication rate was 13.5%, similar to those of previous reports. Complications in our patients included malunion in three, flexor tendinitis in one, complex regional pain syndrome in one, temporary ulnar nerve injury in one, and permanent ulnar nerve injury in one, and there were no significant differences between the two groups regarding complications. This study had several limitations. First, it was retrospective. However, the consecutive patients were prospectively enrolled and divided between two groups according to whether the final digit of their hospital case number was odd or even. Second, our sample size was small and there was no power test. Third, post-traumatic arthritis could not be assessed because the follow-up period was short. Fourth, our results may not be generalizable because we evaluated the outcomes of ORIF using only two implants. For more exact comparison and analysis,

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prospective randomized, controlled clinical trials with longterm follow-up are needed. The strengths of this study included the fact that it is the first comparative study of radiological and clinical outcomes of internal fixation using two different 2.4 mm volar fixed-angle implants for distal radius fractures. The study focused on only a single fracture type, allowing for a more comprehensive understanding of the exact influence of the different plate types on AO type C fractures.

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CONCLUSIONS

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Volar fixed-angle plating for unstable distal radius fractures had satisfactory radiological and clinical outcomes. The difference of implant design did not influence overall final outcomes.

11.

12.

References 1. Buzzell JE, Weikert DR, Watson JT, Lee DH, Precontoured fixed-angle volar distal radius plates: A comparison of anatomic fit, J Hand Surg 33A:1144–1152, 2008. 2. Sammer DM, Fuller DS, Kim HM, Chung KC, A comparative study of fragment-specific versus volar plate fixation of distal radius fractures, Plast Reconstr Surg 122:1441–1450, 2008. 3. Chappuis J, Boute P, Putz P, Dorsally displaced extra-articular distal radius fractures fixation: Dorsal IM nailing versus volar plating. A randomized controlled trial, Orthop Traumatol Surg Res 97:471–478, 2011. 4. Rozental TD, Blazar PE, Franko OI, Chacko AT, Earp BE, Day CS, Functional outcomes for unstable distal radial fractures treated with open reduction and internal fixation or closed reduction and percutaneous fixation. A prospective randomized trial, J Bone Joint Surg 91A:1837–1846, 2009. 5. Zenke Y, Sakai A, Oshige T et al., Clinical results of volar locking plate for distal radius fractures: Conventional versus minimally invasive plate osteosynthesis, J Orthop Trauma 25:425–431, 2011. 6. Grewal R, MacDermid JC, King GJ, Faber KJ, Open reduction internal fixation versus percutaneous pinning with external fixation of distal

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radius fractures: A prospective, randomized clinical trial, J Hand Surg 36A:1899–1906, 2011. Lee YS, Wei TY, Cheng YC, Hsu TL, Huang CR, A comparative study of Colles’ fractures in patients between fifty and seventy years of age: Percutaneous K-wiring versus volar locking plating, Int Orthop 36:789– 794, 2012. Richard MJ, Wartinbee DA, Riboh J, Miller M, Leversedge FJ, Ruch DS, Analysis of the complications of palmar plating versus external fixation for fractures of the distal radius, J Hand Surg 36A:1614–1620, 2011. Phadnis J, Trompeter A, Gallagher K, Bradshaw L, Elliott DS, Newman KJ, Mid-term functional outcome after the internal fixation of distal radius fractures, J Orthop Surg Res 7:4, 2012. von Recum J, Matschke S, Jupiter JB et al., Characteristics of two different locking compression plates in the volar fixation of complex articular distal radius fractures, Bone Joint Res 1:111–117, 2012. Dahl WJ, Nassab PF, Burgess KM et al., Biomechanical properties of fixed-angle volar distal radius plates under dynamic loading, J Hand Surg 37A:1381–1387, 2012. Kamei S, Osada D, Tamai K et al., Stability of volar locking plate systems for AO type C3 fractures of the distal radius: Biomechanical study in a cadaveric model, J Orthop Sci 15:357–364, 2010. Cooney WP, Bussey R, Dobyns JH, Linscheid RL, Difficult wrist fractures. Perilunate fracture-dislocations of the wrist. Difficult wrist fractures, Clin Orthop Relat Res 214:136–147, 1987. Minegishi H, Dohi O, An S, Sato H, Treatment of unstable distal radius fractures with the volar locking plate, Ups J Med Sci 116:280–284, 2011. Rozental TD, Blazar PE, Functional outcome and complications after volar plating for dorsally displaced, unstable fractures of the distal radius, J Hand Surg 31A:359–365, 2006. Stevenson I, Carnegie CA, Christie EM, Kumar K, Johnstone AJ, Displaced distal radial fractures treated using volar locking plates: Maintenance of normal anatomy, J Trauma 67:612–616, 2009. Arora R, Lutz M, Hennerbichler A, Krappinger D, Espen D, Gabl M, Complications following internal fixation of unstable distal radius fracture with a palmar locking-plate, J Orthop Trauma 21:316–322, 2007. Tarallo L, Mugnai R, Zambianchi F, Adani R, Catani F, Volar plate fixation for the treatment of distal radius fractures: Analysis of adverse events, J Orthop Trauma 27:740–745, 2013.

Comparison of radiological and clinical outcomes of internal fixation using two different volar plates for distal radius fractures.

The purpose of this study was to compare the outcomes of volar plating using two different implants for distal radius fractures. Fifty-two patients wi...
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