The Journal of Arthroplasty 31 (2016) 688–693

Contents lists available at ScienceDirect

The Journal of Arthroplasty journal homepage: www.arthroplastyjournal.org

Influence of the Medial Knee Structures on Valgus and Rotatory Stability in Total Knee Arthroplasty Norishige Iizawa, MD, PhD a, Atsushi Mori, MD, PhD a, Tokifumi Majima, MD, PhD b, Hidemi Kawaji, MD, PhD a, Shuhei Matsui, MD a, Shinro Takai, MD, PhD a a b

Department of Orthopaedic Surgery, Nippon Medical School, Tokyo, Japan Department of Orthopaedic Surgery, International University of Health Welfare Hospital, Tochigi, Japan

a b s t r a c t Background: Precise biomechanical knowledge of individual components of the MCL is critical for proper MCL release during TKA. This study was to define the influences of the deep MCL and the POL on valgus and rotatory stability in TKA using cadaveric knees. Methods: This study used six fresh-frozen cadaveric knees. All TKA procedures were performed using a cruciate-retaining TKA with a CT-free navigation system. We did a sequential sectioning on each knee, S1; femoral arthroplasty only, S2; medial half tibial resection with spacer, S3; anterior cruciate ligament cut, S4; tibial arthroplasty, S5; release of the dMCL, S6; release of the POL. The navigation system monitored motion after application of 10 N-m valgus loads and 5 N-m internal and external rotation torques to the tibia at 0°, 20°, 30°, 60°, and 90° of knee flexion for each sequence. Results: There were no significant differences in medial gaps. Internal rotation angles significantly increased after S2 at 0°, 20°, and 30°, and after S6 at 90°compared with those after S1. External rotation angles significantly increased after S3 at 0°, S4 at 60°, S5 at 0°, 30°and 90°, and after S6 at 30°, 60° compared with those after S1. Conclusion: Significant increases of rotatory instability were seen on release of the dMCL, and then further increased after release of the POL. Surgical approach of retaining the dMCL and POL has a possibility to improve the outcome after primary TKA. Article history: Received 14 May 2015 Accepted 21 September 2015 Keywords: deep medial collateral ligament, posterior oblique ligament, biomechanics, instability, soft tissue release, navigation

© 2016 Elsevier Inc. All rights reserved.

Total knee arthroplasty (TKA) is a highly effective procedure that provides reliable relief of pain, improved physical function, and a high level of patient satisfaction in patients with advanced knee osteoarthritis [1]. Although aging may cause a gradual decline in physical activity, an improved functional capacity and activity level continue 20 years or more after TKA [2]. The long-term reports of TKA demonstrate prosthetic survival between 85% [3] and 99% [4] 20 years or more after the index arthroplasty. It has been reported that TKA patients experience a poorer functional outcome than total hip arthroplasty (THA) patients [5,6]. Patients undergoing primary THA reported a greater level of overall satisfaction, satisfaction with pain relief for activities of daily living such as stair climbing, and functional activities such as performing light domestic duties compared with patients undergoing primary TKA [7].

One or more of the authors of this paper have disclosed potential or pertinent conflicts of interest, which may include receipt of payment, either direct or indirect, institutional support, or association with an entity in the biomedical field which may be perceived to have potential conflict of interest with this work. For full disclosure statements refer to http://dx.doi.org/10.1016/j.arth.2015.09.027. Reprint requests: Norishige Iizawa, MD, PhD, Department of Orthopaedic Surgery, Nippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo, 112-0001, Japan. http://dx.doi.org/10.1016/j.arth.2015.09.027 0883-5403/© 2016 Elsevier Inc. All rights reserved.

Unicompartmental knee arthroplasty (UKA) leads to a greater increase in relief of pain and improvement in physical function compared with TKA [8]. No soft tissue involving the medial collateral ligament (MCL) is released in UKA [9-11]; on the other hand, release of the medial components is commonly performed to allow correction of varus knee in TKA [12,13]. It is assumed that release of medial soft tissue structures is one of the reasons why functional outcome of TKA is inferior to UKA. Previous studies have demonstrated that the superficial medial collateral ligament (sMCL), deep medial collateral ligament (dMCL), and posterior oblique ligament (POL) are the main static stabilizing structures of the medial compartment of the knee [14,15]. Several techniques for soft tissue balancing in the varus knee have been described. These generally began with release of the dMCL, after which release of the sMCL and posteromedial capsule including the POL and semimembranosus tendon was performed [16,17]. For severe varus deformity, release of all of these tissues is a common and indispensable step. However, for mild varus deformity, it is unknown whether the dMCL and POL need to be released. Little data have been published concerning the influences of the release of individual medial knee structures on instability in TKA. Precise biomechanical knowledge of the individual components of the MCL is critical for proper MCL release during TKA. We hypothesized that individual sectioning of the

N. Iizawa et al. / The Journal of Arthroplasty 31 (2016) 688–693

689

External Force Application

Table 1 Sequential Sectioning Sequence. S0: intact S1: femoral arthroplasty only S2: medial half tibial resection with spacer S3: ACL cut S4: tibial arthroplasty S5: release of the dMCL S6: release of the POL

medial structures affects knee valgus and rotational stability. The purpose of this study was to define the influences of the dMCL and POL on valgus and rotatory stability in TKA.

Each knee was tested at 0°, 20°, 30°, 60°, and 90° of flexion. Sequential sectioning was performed on each knee, beginning with femoral arthroplasty only (S1), and thereafter sequentially, medial half tibial resection with spacer (S2), anterior cruciate ligament (ACL) cut (S3), tibial arthroplasty (S4), release of the dMCL (S5), and finally, release of the POL (S6) (Table 1; Fig. 1). The same examiner applied all external loads of 10 N · m valgus and 5 N · m internal and external rotation torques to the tibia at each flexion angle and for each cut state. A Model FGJN-20 Digital Force Gauge (Nidec-Shinpo Corp, Kyoto, Japan), with a manufacturer-reported nonrepeatability of ±0.3%, was used to apply valgus loads and internal/external torques. Statistical Analysis

Materials and Methods Specimens and Measurements We used 3 fresh frozen anatomic full-body cadavers for testing. Cadaver experiment was performed at Chula Soft Cadaver Surgical Training Center. No specimen had macroscopic osteoarthritic changes or previous operations concerning the ipsilateral foot and knee. All 6 knees had intact cruciate ligaments. The average age of the subjects was 62 years (range, 55-70 years). All TKA procedures were performed by the same surgeon using a posterior cruciate-retaining TKA (Vanguard; Biomet, Inc, Warsaw, IN) with a CT-free navigation system (Knee 2.6.0; BrainLab, Feldkirchen, Germany). A standard medial parapatellar approach was performed. Two trackers were attached to the specimen using threaded pins at the anterior midfemur and on the anterior tibial crest distal to the tibial tubercle. Thereafter, the navigation system was registered. The neutral position of the intact knee was registered for each testing angle before any load application or sectioning of structures. Approval of this experiment was obtained from institutional investigational review board of Chulalongkorn University, Faculty of Medicine.

A

Two-way analysis of variance was performed to compare each ligament's angular displacement to valgus loads and internal and external rotation torques for each flexion angle for each sectioned state followed by Bonferroni correction for multiple comparison. A significant difference was determined to be present for P b .05. Results There were no significant differences in medial gaps at any sequential step or any tested angle of flexion with valgus loads even after release of the dMCL and the POL compared with those at S1 (Fig. 2). Internal rotation angles significantly increased after S2, compared with those after S1, at 0° (P = .023), 20° (P = .020), and 30° (P = .037). Moreover, S6 resulted in significantly increased internal rotation, compared with that at S1, at 90° of knee flexion (P = .005) (Fig. 3). External rotation angles under external rotation torque significantly increased after S3 compared with those at S1 at 0° (P = .017). After S4, significant increases in external rotation angles compared with those at S1 were observed at 60° (P = .001). Significant increases in external rotation angles were seen, at 0° (P = .045), 30° (P = .030) and 90° (P =

B

C

D

Fig. 1. Picture (A) and schema (B) show S2, medial half tibial resection with spacer (arrow). Pictures show after release of the dMCL (S5) (C) and after release of the POL (S6) (D).

690

N. Iizawa et al. / The Journal of Arthroplasty 31 (2016) 688–693

Medial gap (mm) to applied 10Nm valgus load

10

8

S0

6

S1 S2 S3

4

S4 S5 S6

2

0

0

20

30

60

90

Degrees of knee flexion Fig. 2. Medial gap changes resulting from an applied valgus force (10 N · m). There were no significant differences at any sequential step or any tested angle of flexion compared with S1. Error bars indicate the SEM.

compared with the previous state, after S5 at 0° (P = .032), 30° (P = .026), and 90° (P = .049) and after S6 at 20° (P = .025) (Fig. 5). Total rotational angles had correlation with the size of medial gap at 0° (P = .013), 20° (P = .005), and 90° (P = .007) (Fig. 6). Table 2 summarized the effects of release of dMCL and POL. Maximum medial gap distance was 1.1 mm. That was most obvious at knee flexed 90°. Total maximum rotation increased 5.8°. That was most obvious at knee flexed in 30° and 60°.

.006) after S5 compared with S1, and significant increases were seen after S6 at 30° (P = .048), 60° (P = .001), and 90° (P = .016) compared to S1 (Fig. 4). Total rotation angles significantly increased after S5 compared with S1 at 20° (P = .035), 30° (P = .020), and 90° (P = .001) and after S6 resulted in significantly increased total rotation angles, compared with S1 at 20° (P = .012), 30° (P = .013), 60° (P = .001), and 90° (P = .001). There were significant increases in total rotation angles, 0

Angulation (degrees) to applied 5 Nm internal rotation torque

0

20

30

60

90

-5

-10

S0

-15

S1

a

S2

-20

S3 S4

-25

S5

a

S6

a -30

-35

a -40

Degrees of knee flexion Fig. 3. Knee angulation changes resulting from an applied internal rotation torque (5 N · m). (A) Significant difference compared with the femoral arthroplasty only (S1).

N. Iizawa et al. / The Journal of Arthroplasty 31 (2016) 688–693

691

35

aa b angulation (degrees) to applied 5 Nm external rotation torque

30

b 25

a

a

a 20

a

S0

a

S1 S2

a

S3

15

S4 S5

10

S6

5

0 0

20

30

60

90

Degrees of knee flexion Fig. 4. Knee angulation changes resulting from an applied external rotation torque (5 N · m). (A) Significant difference compared with the femoral arthroplasty only (S1). (B) Significant difference compared with the previous sectioning state. Error bars indicate the SEM.

Discussion We examined the functions of the individual components of the medial knee structures in TKA. There were no significant differences in medial gaps at any sequential step or any tested angle of flexion under valgus loads even after release of the dMCL and the POL. Saeki et al [18] found increases in internal and external rotation with isolated release of the MCL in TKA. The influence of release of the isolated dMCL was not clarified because they released both the sMCL and the dMCL. Luring et al [19] found significant progression in the medial gap distance with release of the dMCL and posteromedial capsule in 10 cadaveric

studies. On the other hand, Griffith et al [20] reported that sectioning of the dMCL did not produce a significant increase in valgus angulation, compared with the intact state, at any knee flexion angle. Release of the dMCL significantly increased some external rotation angles. In addition, release of the POL further increased external rotation angles and internal rotation angles at 90°. Slocum and Larson [21] reported that isolated dMCL rupture occurred when a valgus and external rotation load was applied to the flexed knee. Kennedy and Fowler [22] reported that 45° of tibial external rotation at 90° of knee flexion ruptured the “capsular ligament”. These studies suggested that the dMCL stabilized against external rotation torque in knee flexion. In cadaveric

Angulation (degrees) to applied 5 Nm rotation torque

70.0

a

60.0

a b 50.0

aa

a

a b

a

a

aa bb

a S0

40.0

S1 S2

30.0

aa b

S3 S4 S5

20.0

S6

10.0

0.0

0

20

30

60

90

Degrees of knee flextion Fig. 5. Total knee angulation changes resulting from an applied external and internal rotation torque (5 N · m). (A) Significant difference compared with the femoral arthroplasty only (S1). (B) Significant difference compared with the previous sectioning state. Error bars indicate the SEM.

N. Iizawa et al. / The Journal of Arthroplasty 31 (2016) 688–693

rotation angles

a : 0º

50 40 30

b : 20º

20

r=0.381

10

rotation angles

692

60 50 40 30 20

-5

r=0.426

10 0

0

0

5

0

10

5

70 60 50 40 30 20 10 0

-5

rotation angles -5

15

d : 60º r=-0.070

60 50 40 30 20

r=0.137

10 0

0

5

10

-5

15

0

medial gap

e : 90º

10

medial gap rotation angles

c : 30º

rotation angles

medial gap

70 60 50 40 30 20 10 0

5

10

15

medial gap

r=0.411 0

5

10

15

medial gap Fig. 6. Rotational angles had correlation with the size of medial gap at 0° (P b .05), 20° (P b .01), and 90° (P b .01).

study of the medial knee structures, Robinson et al [23] reported that the dMCL provided some restraint of the knee to tibial external rotation when the knee was flexed beyond 30°, and the posteromedial capsule stabilized tibial internal rotation and posterior drawer in the extended knee, whereas Griffith et al [20] reported that sectioning of the dMCL did not increase external rotation at any knee flexion angle and that sectioning of the POL and the dMCL increased external rotation at 30° and 90°. Sectioning of the dMCL resulted in increased internal rotation at 0°, 20°, 30°, 60°, and 90°, and sectioning of the POL increased internal rotation at all knee flexion angles. Dynamic kinematics in normal knees shows medial pivot motion, femoral external rotation relative to the tibia, with movement from full extension to 120° flexion and bicondylar rollback motion from 120° to maximum flexion [24,25]. Intraoperative medial pivot kinematic patterns in TKA resulted in significantly larger flexion angles and better subjective outcomes when compared with knees demonstrating nonmedial pivot kinematic patterns [26]. Dennis et al [27] reported that 52.9% experienced

a medial pivot motion, 41.1% had a lateral pivot motion, and 7.3% did not experience a pivot motion pattern in a posterior cruciate ligamentretaining fixed-bearing TKA group. Moreover, they found that during a deep knee bend, 72% of patients having a posterior cruciate ligamentretaining TKA experienced greater than 3-mm paradoxical femoral translation during knee flexion. In addition, they reported that surgeon variability could play a significant role in eventual knee kinematic patterns. In the present study, release of the dMCL increased external rotational instability. In addition, external and internal instability further increased after release of the POL. Differences in surgical technique among surgeons, such as the soft tissue release, may affect variability in knee kinematics. Because sacrifice of the ACL, which is an important structure for rotation stability of the knee, is unavoidable in TKA, we should try to retain other rotation-stabilizing structures, such as the dMCL and the POL. A limitation of the present study was that it was a cadaveric sectioning study using normal knees. As a result, we cannot evaluate effect of scar formation after release of medial structures that may affect stability

Table 2 Increase in Motion Limits Relative to the Femoral Arthroplasty Only Knee (Mean ± SD).

Medial gap (mm)

External rotation (°)

Internal rotation (°)

Total rotation (°)

⁎ P b .05.

Tibial arthroplasty Release of the dMCL Release of the POL Tibial arthroplasty Release of the dMCL Release of the POL Tibial arthroplasty Release of the dMCL Release of the POL Tibial arthroplasty Release of the dMCL Release of the POL



20°

30°

60°

90°

0.7 ± 2.2 1.3 ± 2.9 1.2 ± 2.6 1.9 ± 3.9 2.8 ± 3.3 3.3 ± 5.2 1.3 ± 3.2 0.2 ± 4.8 −0.4 ± 5.7 0.7 ± 6.5 2.7 ± 6.6 3.8 ± 9.2

0.3 ± 1.1 1.3 ± 3.4 1.9 ± 2.9 2.8 ± 3.0 4.4 ± 3.1 4.9 ± 5.4 0.0 ± 3.6 −0.1 ± 4.0 −2.7 ± 5.7 2.8 ± 5.2 4.5 ± 4.8 7.6 ± 7.3

0.6 ± 2.8 1.0 ± 3.8 1.8 ± 3.1 1.9 ± 4.3 4.3 ± 4.4 4.7 ± 5.6 −0.8 ± 4.8 −0.2 ± 4.9 −3.8 ± 5.9 2.7 ± 4.4 4.5 ± 4.0 8.5 ± 6.7

1.0 ± 3.2 1.7 ± 4.1 1.8 ± 4.4 4.8 ± 1.7 4.0 ± 8.1 6.8 ± 2.5 2.4 ± 2.9 0.4 ± 3.5 −1.4 ± 3.0 2.4 ± 2.8 3.6 ± 7.3 8.2 ± 3.2

1.7 ± 3.4 1.3 ± 3.5 2.8 ± 3.9 2.7 ± 4.5 5.0 ± 3.2 5.9 ± 4.9 −2.4 ± 3.8 −3.2 ± 4.5 −4.5 ± 2.7 5.1 ± 5.3 8.2 ± 3.4 10.4 ± 4.4

N. Iizawa et al. / The Journal of Arthroplasty 31 (2016) 688–693

after surgery. A second limitation is the number of recruited knees is too small. A third limitation was that there was no weight bearing measurement. Therefore, motion changes in vivo could not be reproduced. We found significant increases of rotatory instability on release of the dMCL, whereas increases of medial gap size were not clearly recognized. In addition, rotatory instability further increased after release of the POL. Moreover, as medial gap size increased, rotatory instability correlatively increased. Accordingly, we concluded that retaining of the medial knee structures, especially the dMCL and the POL, preserves the valgus and rotatory stability of the healthy knee in TKA done on cadavers. Retaining of the dMCL and the POL has a possibility to improve the functional outcome after primary TKA.

References 1. Hawker G, Wright J, Coyte P, et al. Health-related quality of life after knee replacement. J Bone Joint Surg Am 1998;80:163. 2. Meding JB, Meding LK, Ritter MA, et al. Pain relief and functional improvement remain 20 years after knee arthroplasty. Clin Orthop Relat Res 2012;470:144. 3. Rodriguez JA, Bhende H, Ranawat CS. Total condylar knee replacement: a 20-year follow-up study. Clin Orthop Relat Res 2001;388:10. 4. Gill GS, Joshi AB. Long-term results of kinematic condylar knee replacement: an analysis of 404 knees. J Bone Joint Surg (Br) 2001;83:355. 5. Wylde V, Blom AW, Whitehouse SL, et al. Patient-reported outcomes after total hip and knee arthroplasty. J Arthroplasty 2009;24:210. 6. Rat AC, Guillemin F, Osnowycz G, et al. Total hip or knee replacement for osteoarthritis: mid- and long-term quality of life. Arthritis Care Res 2010;62:54. 7. Bourne RB, Chesworth B, Davis A, et al. Comparing outcomes after THA and TKA. Clin Orthop Relat Res 2010;468:542. 8. Noticewala MS, Geller JA, Lee JH, et al. Unicompartmental knee arthroplasty relieves pain and improves function more than total knee arthroplasty. J Arthroplasty 2012; 27:99. 9. Argenson JN, Parratte S, Flecher X, et al. Unicompartmental knee arthroplasty. Technique through a mini-incision. Clin Orthop Relat Res 2007;464:32.

693

10. Lim MH, Tallay A, Bartlett J. Comparative study of the use of computer assisted navigation system for axial correction in medial unicompartmental knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 2009;17:341. 11. Tashiro Y, Matsuda S, Okazaki K, et al. The coronal alignment after medial unicompartmental knee arthroplasty can be predicted: usefulnesss of full-length valgus stress radiography for evaluating correctability. Knee Surg Sports Traumatol Arthrosc 2014;22:3142. 12. Insall J, Scott WN, Ranawat CS. The total condylar knee prosthesis. J Bone Joint Surg Am 1979;61:173. 13. Whiteside LA, Saeki K, Mihalko WM. Functional medial ligament balancing in total knee arthroplasty. Clin Orthop Relat Res 2000;380:45. 14. Brantigan OC, Voshell AF. The tibial collateral ligament: its function, its bursae, and its relation to the medial meniscus. J Bone Joint Surg 1943;25:121. 15. LaPrade RF, Engebreten AH, Ly TV, et al. The anatomy of the medial part of the knee. J Bone Joint Surg Am 2007;89:2000. 16. Verdonk PC, Pernin J, Pinaroli A, et al. Soft tissue balancing in varus total knee arthroplasty: an algorithmic approach. Knee Surg Sports Traumatol Arthrosc 2009;17:660. 17. Mullaji A, Marawar S, Sharma A. Correcting varus deformity. J Arthroplasty 2007;22:15. 18. Saeki K, Mihalko WM, Patel V, et al. Stability after medial collateral ligament release in total knee arthroplasty. Clin Orthop Relat Res 2001;392:184. 19. Luring C, Hufner T, Perlick L, et al. The effectiveness of sequential medial soft tissue release on coronal alignment in total knee arthroplasty. J Arthroplasty 2006;21:428. 20. Griffith CJ, LaPrade RF, Johansen S, et al. Medial knee injury. Part 1, static function of the individual components of the main medial knee structures. Am J Sports Med 2009;37:1762. 21. Slocum DB, Larson RL. Rotatory instability of the knee: its pathogenesis and a clinical test to determine its presence. J Bone Joint Surg Am 1968;50:211. 22. Kennedy JC, Fowler PJ. Medial and anterior instability of the knee. J Bone Joint Surg Am 1971;53:1257. 23. Robinson JR, Bull AM, Thomas RR, et al. The role of the medial collateral ligament and posteromedial capsule in controlling knee laxity. Am J Sports Med 2006;34:1815. 24. Komistek RD, Dennis DA, Mahfouz M. In vivo fluoroscopic analysis of the normal human knee. Clin Orthop Relat Res 2003;410:69. 25. Freeman MAR, Pinskerova V. The movement of the normal tibio-femoral joint. J Biomech 2005;38:197. 26. Nishio Y, Onodera T, Kasahara Y, et al. Intraoperative medial pivot affects deep knee flexion angle and patient-reported outcomes after total knee arthroplasty. J Arthroplasty 2014;29:702. 27. Dennis DA, Komistek RD, Mahfouz MR, et al. Multicenter determination of in vivo kinematics after total knee arthroplasty. Clin Orthop Relat Res 2003;416:37.

Influence of the Medial Knee Structures on Valgus and Rotatory Stability in Total Knee Arthroplasty.

Precise biomechanical knowledge of individual components of the MCL is critical for proper MCL release during TKA. This study was to define the influe...
566B Sizes 2 Downloads 20 Views