Long-term function and imaging changes of the knee in patients with partial patellectomy

Abstract

Objective To investigate the long-term function and imaging changes of the knee in patients with partial patellectomy.Methods From January 1987 to January 2002,29 patients underwent partial patellectomy in our hospital.They were 21 men and 8 women,with an average age of 45.8 years (range,29 to 71 years).At the last follow-up,the knee function of all the patients was examined by MRI and physical examinations and questionnaire.The MRI results were evaluated by modified Whole-Organ Magnetic Resonance Imaging Score (WORMS) of the knee.The knee function was also assessed by Knee Injury and Osteoarthritis Outcome Score (KOOS) and Bostman's Score.Results The 29 patients were followed up for 8 to 18 years (average,13 years).The average modified WORMS score of the affected knee was 13.8 ± 5.8 points in 24 cases of mild and 5 cases of moderate arthritis; the score of the unaffected side was 12.3 ± 5.5 points in 26 cases of mild and 3 cases of moderate arthritis.There was no statistically significant difference between the 2 groups (t =1.001,P =0.321).The average KOOS for pain was 88.0 ± 6.4 points,for symptom 86.9 ± 5.7 points,for daily life 89.9 ± 5.2 points,for entertainment and sports 83.6 ± 7.6 points,and for the quality of life related to knee joint function 80.5 ± 8.5 points.The average Bostman's score was 27.4 points in 20 excellent to good patients and 9 moderate ones.The flexion was 128.3° ± 5.5° for the involved side and 128.8° ±4.2° for the uninvolved knee; the peak torque averaged 105.4 ± 12.2 N · m for the involved side and 106.6 ± 9.1 N · m for the uninvolved knee.There were no statistically significant differences regarding the above 2 parameters between the 2 sides (P ＞ 0.05).Conclusions Partial patellectomy may not cause serious joint degeneration or traumatic arthritis,for its long-term outcomes are fine.This procedure can be used for patellar fractures whose reduction is difficult or unsatisfactory. Key words: Patella; Fractures, bone; Treatment outcome; Partial resection