Total knee arthroplasty in a non-ambulatory patient having bilateral knees ankylosed in 90° of flexion associated with rheumatoid arthritis: a review-based case report.

BACKGROUND

Management of severe knee flexion deformity exceeding 80° with arthritis presents significant surgical challenges in total knee arthroplasty (TKA). While various studies have reported outcomes in severe flexion deformity, TKA in ankylosed knees at 90° flexion represents an unprecedented surgical scenario where further flexion and extension are not possible due to contracture of both hamstring and quadriceps. We hereby present the rarest case of ankylosed knee in 90° flexion, which was successfully managed by constrained condylar knee-total knee arthroplasty (CCK-TKA).

METHODS

A 52-year-old male with long-standing rheumatoid arthritis presented with bilateral knee fixed at 90° flexion following an episode of acute fever 10 years back. The patient underwent bilateral constrained condylar knee-total knee arthroplasty (CCK-TKA) with rectus snip approach, including extensive posterior release, upsizing femoral component in a single sitting. Postoperative management included correction of residual flexion deformity using dynamic knee fixed flexion deformity correction bracing and intensive physiotherapy.

RESULTS

At the 9 month follow-up, the patient achieved functional ambulation with minimal support. Outcome measures demonstrated satisfactory results: KSS-Knee scores (right: 66 and left: 78), KSS-Function scores (right: 55 and left: 65), WOMAC scores (right: 32 and left: 23), and KOOS scores (right: 60.1 and left: 66.7).

CONCLUSION

This case proposes the use of constrained condylar knee-total knee arthroplasty (CCK-TKA) as an effective solution to balance knees ankylosed at severe flexion deformity, combined with gradual correction of residual deformity with dynamic bracing as a viable rehabilitation option, providing a framework for managing similar challenging cases.