Total knee replacement following intra-articular malunion

SummaryIntroductionThere is a lack of data on the management of osteoarthritis of the knee associated with intra-articular malunion. The present study sought to analyze and report results of total knee replacement (TKR) in this indication, including complications and technical specificities.HypothesisTKR for osteoarthritis of the knee associated with intra-articular malunion entails an elevated risk of complication, with impaired functional results.ObjectivesTo test this hypothesis in a retrospective series of 74 cases of osteoarthritis of the knee associated with intra-articular malunion.Patients and methodsA multicenter retrospective series collated the records of 74 patients (mean age, 63 ± 14 years) who underwent TKR for post-traumatic osteoarthritis of the knee associated with intra-articular malunion between 2000 and 2008. Mean trauma-to-TKR interval was 21.8 ± 19 years (range 1 to 56 years). Patients were assessed clinically and radiologically at last follow-up, using the Knee Society score as modified by the Western France Orthopedic Society (Société orthopédique de l’Ouest).ResultsAt a mean overall follow-up of 4 ± 3 years (range 1 to 9 years), mean knee score improved from 25 ± 12 to 85 ± 7 (P < 0.001) and mean functional score from 52 ± 13 to 66 ± 10 (P = 0.004). Mean flexion gain was 6°: mean preoperative flexion, 104° ± 28° (10° to 150°), vs. 110° ± 19° (20° to 130°) at follow-up. Nineteen patients (26%) had complications, 13 of which were severe and liable to affect the functional result: three extensor system avulsions, four infections, five cases of stiffness and one of instability.Discussion and conclusionsThe present results highlight an elevated rate of complications, with poorer clinical results than those found with osteoarthritis of the knee secondary to constitutional deformity. The initial trauma, with associated hemarthrosis, and sometimes iterative surgery to reduce and fix the initial fracture, induce fibrosis and synovial attachments, leading to stiffness and hindering exposure. The patient should be informed, and warned that postoperative flexion amplitude may be improved but is bound to remain limited, especially in case of initial stiffness.Level of evidenceLevel IV: non-comparative retrospective study.