Comparative evaluation of the results of using the Ilizarov apparatus and an orthopedic hexapod in the treatment of patients with flexion knee joint contractures

Relevance When soft tissue release is ineffective in the treatment of persistent flexion contractures of the knee joint, external fixation devices are used. Orthopedic hexapods can be used as an alternative to the traditional Ilizarov frame with a uniaxial hinge.

Purpose To conduct a comparative analysis of the effectiveness of the clinical use of an orthopedic hexapod and the Ilizarov fixator with a uniaxial hinge in the treatment of patients with flexion contractures of the knee joint.

Materials and methods A total of 67 cases of flexion contracture of the knee joint due to spastic paresis were analyzed. All patients underwent posterior release surgery followed by the application of an external fixation device (EFD). Patients were divided into two groups: the study group (n = 35) treated using the "Orto-SUV" orthopedic hexapod, and the comparison group (n = 32) treated using the Ilizarov fixator with a uniaxial hinge. Patients were also subdivided based on the presence or absence of a preoperatively diagnosed posterior tibial subluxation. The duration of treatment stages, range of motion in the knee joint and functional outcomes (assessed with KSS, Lysholm, and LEFS systems) were evaluated at 2 days, 6 months, and 12 months after frame removal.

Results The use of the orthopedic hexapod significantly reduced the duration of the extension stage compared to the Ilizarov fixator. However, the overall duration of external fixation in both groups did not differ significantly. No statistically significant differences were found between the groups at any follow-up time-point for the main functional indicators: range of motion (flexion and extension) and overall lower extremity function (LEFS score). However, according to specialized knee joint assessment scales (KSS and Lysholm), patients in the study group demonstrated significantly better results at 12 months. The complication rate in both groups was comparable.

Discussion Factors affecting functional outcomes in both groups included preoperative tibial subluxation and patient compliance with postoperative recommendations. A specific factor affecting functional outcomes for a uniaxial external fixator is the precise positioning of the hinge on the flexion-extension axis to avoid iatrogenic knee instability. The total duration of external fixation and overall lower extremity function (LEFS) in the compared groups did not differ statistically, indicating no significant advantage of using one type of device over the other.

Conclusion With the orthopedic hexapod, the extension stage was significantly shorter than with the Ilizarov fixator; however, the total duration of externalfixation in both groups did not differ significantly. No statistically significant differences were found between the groups at any follow-up point in terms of the main functional indicators, range of motion (flexion and extension), and LEFS. Based on the KSS and Lysholm scales, patients in the study group demonstrated significantly better results at 12 months. Complication rates were comparable in both groups.

1. Richards C, Higginson JS. Knee contact force in subjects with symmetrical OA grades: differences between OA severities. J Biomech. 2010;43(13):2595-2600. doi: 10.1016/j.jbiomech.2010.05.006.

2. Attias M, Chevalley O, Bonnefoy-Mazure A, et al. Effects of contracture on gait kinematics: A systematic review. Clin Biomech (Bristol). 2016;33:103-110. doi: 10.1016/j.clinbiomech.2016.02.017.

3. Sendroy-Terrill M, Whiteneck GG, Brooks CA. Aging with traumatic brain injury: cross-sectional follow-up of people receiving inpatient rehabilitation over more than 3 decades. Arch Phys Med Rehabil. 2010;91(3):489-497. doi: 10.1016/j. apmr.2009.11.011.

4. Wissel J, Verrier M, Simpson DM, et al. Post-stroke spasticity: predictors of early development and considerations for therapeutic intervention. PM R. 2015;7(1):60-67. doi: 10.1016/j.pmrj.2014.08.946.

5. Ogorodova II, Zagorodneva VI, Ogorodov IA, Belaya NN. Morphological changes of the children’s muscular apparatus with spastic forms of cerebral palsy during different approaches to the treatment. Child and adolescent rehabilitation. 2014;(1):24-30. (In Russ.)

6. Zinovyeva OE, Golovacheva VA. Questions of pathogenesis and treatment of post-stroke spasticity. Medical Council. 2016;(8):63-67. (In Russ.) doi: 10.21518/2079-701X-2016-8-63-67.

7. Vahedi H, Khlopas A, Szymczuk VL, et al. Treatment with posterior capsular release, botulinum toxin injection, hamstring tenotomy, and peroneal nerve decompression improves flexion contracture after total knee arthroplasty: minimum 2-year follow-up. Knee Surg Sports Traumatol Arthrosc. 2020;28(8):2706-2714. doi: 10.1007/s00167-02005939-0.

8. Chung CY, Kwon SS, Park MS, et al. Surgical outcomes after single event multilevel surgery in cerebral palsy patients with mid-stance knee hyperextension. Gait Posture. 2020;77:1-5. doi: 10.1016/j.gaitpost.2020.01.005.

9. Bozinovski Z, Popovski N. Operative treatment of the knee contractures in cerebral palsy patients. Med Arch. 2014;68(3):182-183. doi: 10.5455/medarh.2014.68.182-183.

10. Jones S, Al Hussainy HA, Ali F, et al. Davies AG. Distal hamstring lengthening in cerebral palsy: the influence of the proximal aponeurotic band of the semimembranosus. J Pediatr Orthop B. 2006;15(2):104-108. doi: 10.1097/01. bpb.0000179272.61726.a0.

11. Sung KH, Lee J, Chung CY, et al. Factors influencing outcomes after medial hamstring lengthening with semitendinosus transfer in patients with cerebral palsy. J Neuroeng Rehabil. 2017;14(1):83. doi: 10.1186/s12984-017-0296-0.

12. Karol LA, Chambers C, Popejoy D, Birch JG. Nerve palsy after hamstring lengthening in patients with cerebral palsy. J Pediatr Orthop. 2008;28(7):773-776. doi: 10.1097/BPO.0b013e318186bdbb.

13. Gaurav K, Vilas J. A new approach to the management of fixed flexion deformity of the knee using Ilizarov's principle of distraction histogenesis: a preliminary communication. Int J Low Extrem Wounds. 2010;9(2):70-73. doi: 10.1177/1534734610371559.

14. Balci HI, Kocaoglu M, Eralp L, Bilen FE. Knee flexion contracture in haemophilia: treatment with circular external fixator. Haemophilia. 2014;20(6):879-883. doi: 10.1111/hae.12478.

15. Yadkikar S, Grover R, Kaur P, et al. Soft-tissue origin joint contractures treated with the Ilizarov fixation method. Genij Ortopedii. 2024;30(2):255-262. doi:10.18019/1028-4427-2024-30-2-255-262.

16. Sommers MB, Fitzpatrick DC, Kahn KM, et al. Hinged external fixation of the knee: intrinsic factors influencing passive joint motion. J Orthop Trauma. 2004;18(3):163-169. doi: 10.1097/00005131-200403000-00007.

17. Rokhoev SA, Solomin LN, Starchik DA. Template of instant centers of rotation developed for the knee joint (experimental study). Genij Ortopedii. 2022;28(4):554-558. doi: 10.18019/1028-4427-2022-28-4-554-558.

18. Rokhoev SA, Solomin LN. Usage of External Fixation in the Treatment of Adult Patients with Knee Joint Stiffness: Review. Traumatology and Orthopedics of Russia. 2021;27(1):185-197. (In Russ.) doi: 10.21823/2311-2905-2021-27-1185-197.

19. 19. Rokhoev S.A., Chugaev D.V., Solomin L.N. Treatment of Extension Knee Contractures with Ilizarov Apparatus Versus Orthopedic Hexapod Ortho-SUV Frame. Traumatology and Orthopedics of Russia. 2021;27(1):185-197. 2022;28(2):7-19. doi: 10.17816/2311-2905-1756.

20. Solomin LN, Schepkina EA, Vilensky VA, et al. Correction of femur deformities by ilizarov method and by apparatus “Ortho-Suv” based on computer navigation. Traumatology and Orthopedics of Russia. 2011;17(3):32-39. (In Russ.) doi: 10.21823/2311-2905-2011-0-3-32-39.

21. Herzenberg JE, Davis JR, Paley D, Bhave A. Mechanical distraction for treatment of severe knee flexion contractures. Clin Orthop Relat Res. 1994;(301):80-88.

22. Volkov MV, Oganesyan OV. Reduction of the shape and function of joints and bones (by the authors’ apparatus). Moscow.: Meditsina; 1986:256. (In Russ.)

23. Hollister AM, Jatana S, Singh AK, et al. The axes of rotation of the knee. Clin Orthop Relat Res. 1993;290:259-268.

24. Caton J. Treatment of leg length discrepancies and short stature in children and adolescents. Rev Chir Orthop. 1991;77 (Suppl. I):31-80. (In Franc.)

25. Kettelkamp DB, Chao EY. A method for quantitative analysis of medial and lateral compression forces at the knee during standing. Clin Orthop Relat Res. 1972;83:202-213. doi: 10.1097/00003086-197203000-00037.

26. Tegner Y, Lysholm J. Rating systems in the evaluation of knee ligament injuries. Clin Orthop Relat Res. 1985;(198):43-49.

27. Dingemans SA, Kleipool SC, Mulders MAM, et al. Normative data for the lower extremity functional scale (LEFS). Acta Orthop. 2017;88(4):422-426. doi: 10.1080/17453674.2017.1309886.

28. Krupko IL. Handbook of Traumatology and Orthopedics. Book 2. Orthopedics. Leningrad: Medicine; 1975:270. (In Russ.)

29. Vulcano E, Markowitz JS, Fragomen AT, Rozbruch SR. Gradual correction of knee flexion contracture using external fixation. J Limb Lengthen Reconstr. 2016;2(2):102-107. doi: 10.4103/2455-3719.190712.

30. Damsin JP, Ghanem I. Treatment of severe flexion deformity of the knee in children and adolescents using the Ilizarov technique. J Bone Joint Surg Br. 1996;78(1):140-144.

31. Huang SC. Soft tissue contractures of the knee or ankle treated by the Ilizarov technique. High recurrence rate in 26 patients followed for 3-6 years. Acta Orthop Scand. 1996;67(5):443-449. doi: 10.3109/17453679608996665.

32. Zhai J, Weng X, Zhang B, et al. Management of knee flexion contracture in haemophilia with the Ilizarov technique. Knee. 2019;26(1):201-206. doi: 10.1016/j.knee.2018.08.006.