Patient-specific implants for lateral unicompartmental knee arthroplasty

The lateral compartment of the knee is biomechanically and anatomically different from the medial compartment. Most commercially available unicompartmental implants are not designed specifically for the lateral compartment. Patient-specific custom-made unicompartmental knee arthroplasty (UKA) are designed to provide optimal fit on both femoral and tibial surfaces. This study aimed to determine if the use of patient-specific lateral unicompartmental implants provide better bone coverage than standard, off-the-shelf commercially available unicompartmental implants in lateral unicompartmental knee arthroplasties. As a secondary question, we wished to determine if patient-specific unicompartmental implants provide good clinical outcomes in surgical treatment of lateral unicompartmental osteoarthritis.

We prospectively evaluated 33 patients who underwent lateral unicompartmental arthroplasty using patient-specific implants and instrumentation with a minimum of 24 months of follow-up. We analysed bone coverage observed in plain radiographs in 33 patient-specific lateral unicompartmental arthroplasties and compared to 20 lateral unicompartmental arthroplasties performed with commercially-available, standard off-the-shelf unicondylar implants.

Patient-specific lateral unicompartmental knee replacements demonstrated better tibial coverage and provide excellent short-term clinical and radiological results as compared to a standard lateral UKA.