Unicompartmental arthroplasty in athletic individuals with osteoarthritis in the past have had limited success returning patients to sports. Patients who are arthritic and symptomatic in one compartment of the knee may provide better physiological function and quicker recovery compared with knee arthroplasty. The purpose of this study was to prospectively evaluate outcomes following lateral unicompartmental knee arthroplasty.
Patients that underwent unicompartmental arthroplasty by one surgeon from 2000-2005 were prospectively studied. Nineteen patients underwent lateral unicompartmental knee replacements. The average age for the lateral unicompartmental group was 68 (range, 50-80). Assessment included preoperative and postoperative range of motion, subjective testing, KT-1000, radiographic evaluation consisting of a full plain radiograph knee series including 3-foot alignment films. An MRI was completed in all patients but one who had a pacemaker. All patients had the same implant utilized.
All patients reported severe knee pain preoperatively involving the lateral compartment. No patients were lost to follow-up. One patient was converted to a total knee arthroplasty. Average follow-up was 33 months (range: 24-56 months). The average post-surgical Lysholm score was 91 (range, 67-100) points with a pre-operative Lysholm score of 64 (P=0.001). The pre-operative Tegner was 4 (range, 1-7) with a postoperative Tegner of 5 (range, 1-8) (p=0.001). The preoperative HSS score was 67 (range, 45-87) with a postoperative score of 92 (range, 82-100) (p=0.001). Physical examination and subjective questioning along with MRI correlation helped predict successful outcomes. The average medial compartment Outerbridge grade was 2.2 for the medial femoral condyle and 2.3 for the medial tibial plateau. The average trochlear groove Outerbridge grade was 2.3 and for the patella was 2.2. Overall, patients reported a return to skiing in 5 months, tennis in 4 months, and 1-2 months for walking and jogging.
Determining specific patient selection criteria improves patient outcomes and helps with patient education. This study will give the guidelines necessary to offer an alternative to repeat arthroscopic intervention or total knee arthroplasty and allow patients the ability to return to their activities of daily living and sport. Long term results need to be carefully followed. We are not aware of any previous study attempting to report success with lateral unicondylar knee arthroplasty in a population having returned to sport.
© 2010 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.