Primary Total Knee Replacement using Rotating Hinge Implants in Poliomyelitis: A Case Series and Review of the Literature.

Introduction: The results of primary total knee replacement (TKR) using hinge implants performed in the Indian population with post-polio residual paresis (PPRP) are unknown. The purpose of this study was to report the outcome of primary rotating hinge TKR in Indian patients with PPRP at a minimum follow-up of 12 months. Materials and Methods: We retrospectively reviewed the clinical and radiological records of six patients treated with primary rotating hinge TKR. Pre-and post-operative (at final follow-up) knee range of motion (ROM), knee sagittal deformity, knee society score (KSS), and Oxford knee score (OKS) were compared to determine improvement in function. Results: Six rotating hinge TKRs (five female and one male patient) were analyzed for this study. At a mean follow-up of 27 ± 22 months (range, 12-71 months), the mean pre-operative KSS of 50.6 ± 2.5 significantly improved (P < 0.0001) to 72.5 ± 1.6, and the mean pre-operative OKS of 23.6 ± 1.6 significantly improved (P < 0.0001) to 35.3 ± 1.7. The mean pre-operative knee ROM of 94° ± 10° changed to 92° ± 4° (P = 0.64) and the mean pre-operative sagittal deformity of 7° ± 23.5° changed to -3° ± 2.5° (P = 0.32) at final follow-up. None of the knees had any intra- or post-operative complications or showed radiologic evidence of post-operative loosening, subsidence, or periprosthetic radiolucent lines at the final follow-up. Conclusion: Rotating hinge TKR gave excellent clinical and radiological results at a mean follow-up of 27 months in the present study. Despite TKR being a technically challenging procedure in patients with poliomyelitis-affected limbs, a rotating hinge design, along with meticulous surgical technique, can significantly improve function in such patients.