Midterm Results of Medial Unicompartmental Knee Arthroplasty Performed in Patients With Lateral Meniscus Abnormalities on Preoperative MRI Without Symptoms Related to Lateral Meniscus

The purpose of the present study was to compare the functional outcomes of medial unicompartmental knee arthroplasty (UKA) between patients with lateral meniscal abnormalities (LM [+] group) on the preoperative magnetic resonance imaging and those without lateral meniscal pathology (LM [–] group) and to evaluate the effect of a lateral meniscus lesion on functional outcomes after minimal 5 year follow-ups of medial UKA.

The outcomes of 66 knees (LM (+) group) were compared with the outcomes of 59 knees (LM (−) group) with a mean follow-up period of 75 months (range 60-93 months). The clinical outcomes were examined including the KS object/function score, Knee Injury and Osteoarthritis Outcome score, lateral side pain, and squatting ability at the last follow-up. The radiological parameters (mechanical axis and component position) were compared at the final follow-up visit.

No significant intergroup difference was found in terms of the KS object/function score, Knee Injury and Osteoarthritis Outcome score, presence of lateral side pain, and squatting ability. On the radiographic evaluation, there was no statistical difference in the position of the implant and mechanical axis between the two groups. After the surgery, the LM (+) group showed a tendency of slight varus alignment in the postoperative radiography.

The results of UKA for medial unicompartmental knee osteoarthritis were excellent regardless of preoperative lateral meniscal pathology in the magnetic resonance imaging, if the patients had no symptoms related to the lateral meniscus lesion.