Total Knee Arthroplasty in Rheumatoid Arthritis patients with a medial stabilized prosthesis - A retrospective...

Total Knee Arthroplasty (TKA) has been described as an effective and successful mode of treatment in alleviation of pain and restoration of function in patients with Rheumatoid Arthritis (RA). The array of bone and soft tissue deformities in RA patients can impact initial success and long term durability of TKA. Medial Pivot (MP) prosthesis is fixed bearing asymmetric pivoting design that provides anterior-posterior stability without any post and conserves bone on the femoral side. There are few reports of suitability of experience with MP in RA.

Twenty six patients (average age 55 years) with end stage arthritis secondary to RA operated with MP prosthesis were retrospectively followed up. At a minimum follow up of three years, all patients were assessed using Knee Society Score (KSS), Oxford Knee Score (OKS), Pain Catastrophising Scale (PCS) and radiological outcomes.

At final follow-up, patients reported significant improvement in mean KSS-Objective and Functional scores, Oxford Knee Score and Pain Catastrophising Scale (p < 0.05). The mean range of motion achieved at the end of two years ranged from 0 ͦ (extension) to 109.4 ͦ (full flexion). There was no evidence of loosening or osteolysis at minimum follow up of three years.

These results endorse satisfactory clinical and radiological outcomes at minimum follow up of three years following Medial Pivot Prosthetic Knee design in RA patients. Further long term follow up is needed to determine the survival analysis of MP design in these patients.