[Clinical outcomes analysis of medial unicompartmental knee arthroplasty via a short median incision approach for patients with concurrent severe patellar osteophyte hyperplasia].

OBJECTIVE: To explore the influence of severe patellar osteophyte hyperplasia on knee joint range of motion (ROM), and evaluate the clinical efficacy of unicompartmental knee arthroplasty (UKA) performed via a short median incision approach for patients with medial knee osteoarthritis combined with severe peripatellar osteophyte hyperplasia.

METHODS: A retrospective analysis was performed on 41 patients diagnosed with severe osteophyte hyperplasia surrounding the patella, combined with medial compartment knee osteoarthritis, between February 2018 and November 2019. The cohort included 18 males and 23 females, aged from 51 to 72 years old with a mean age of (60.59±6.25 ) years od. All patients underwent UKA through a short medial incision approach. Each patient received concomitant patellar reshaping, peripatellar denervation, and lateral patellar retinacular management as part of the surgical protocol. Follow up on the current status of prosthesis survival in the patients;conduct a statistical analysis of anterior knee pain before and after surgery;observe and record the ROM of the knee joint at multiple time points, including preoperatively, after anesthesia, intraoperatively, three months postoperatively, and at the final follow-up. The Hospital for Special Surgery (HSS) scores were statistically analyzed preoperatively, at 1 week postoperatively, at 3 months postoperatively, and at the final follow-up after surgery.

RESULTS: All 41 patients postoperative incisions healed well, and the prostheses were well tolerated. Among the 15 patients who had anterior knee pain before the operation, none experienced anterior knee pain after the operation. All 41 patients completed postoperative follow-up, with a duration raging from 1.5 to 3.5 years with an average of (2.6±0.5) years. The ROM was measured at (94.76±3.15)° before surgery, (104.27±5.12)° following anesthesia, and (120.24 ±1.09)° after surgery. At the 3-month postoperative follow-up, the ROM was recorded as (120±0.00)°, and at the final follow-up, it was (121.17±2.11)°. Statistically significant differences were observed between pre-anesthesia and post-anesthesia measurements, as well as between post-anesthesia and post-surgery values (P<0.05). The HSS score was (52.39±3.79 ) points preoperatively, (57.23±5.98) points at 1 week postoperatively, (86.97±3.72 ) points at 3 months postoperatively, and( 88.02±4.22) points at the final follow-up. A statistically significant improvement was observed between the preoperative measurement and the measurements taken one week and three months postoperatively (P<0.05). No statistically significant difference was found between the scores at three months postoperatively and at the final follow-up (P>0.05).

CONCLUSION: Severe osteophyte hyperplasia of the patella is a direct factor influencing knee joint ROM. Unicompartmental knee arthroplasty through the surgical approach of short medial incision for patients with medial knee osteoarthritis and severe osteophyte hyperplasia around the patella, realizing patellar eversion during surgery, removing osteophytes and peripatellar denervation, effectively resolves knee joint ROM and avoids the occurrence of anterior knee pain, achieving considerable clinical efficacy.