The arthroscopic diagnosis and treatment of acute patellofemoral joint impingement syndrome

Abstract

Objective To explore the mechanism and characteristics of MRI of acute patellofemoral joint impingement syndrome as well as its arthroscopic diagnosis and treatment. Methods There were a total of 46 cases (9 males and 37 females) with acute patellofemoral joint impingement syndrome from September 2005 to October 2012 in our department, and their average age was 21.6 years old (ranging from 15 to 31 years old). The Q angle, lateral patellofemoral angle (LPA) and lateral shift distance(LSD) of all cases were measured by X-ray and MRI preoperatively. MRI checked the medial patellar retinaculum injury by 4 de-grees: 15 cases of degree Ⅰ, 18 cases of degree Ⅱ, 8 cases of degree Ⅲ, and 5 cases of degree Ⅳ. All operations were monitored under arthroscopy. Firstly, the hemarthrosis was cleared, and secondly arthroscopy was used to explore all around inside joints, the free cartilage and osteochondral fragment were taken out, and the impaired surface of cartilage was repaired. Medial patellar reti-naculum was treated arthroscopically with radio frequency ablation in degree Ⅰ injury. Lateral patellar retinaculum was released when the time of injury was longer than 2 weeks (9 cases), and medial capsule and retinaculum structure were reefed with modified arthroscopy assistance for patients with medial patellar retinaculum injury of degree Ⅱ to Ⅲ with obvious patellar shift. The medi-al capsule and retinaculum structure were strengthened by open surgical method for patients with degree Ⅳ injury. Results Constant findings under arthroscopy were haemarthrosis (46 cases), chondral lesions involved in the lateral femoral condyle and medi-al marginal of patella (37 cases), osteochondral fragments (28 cases), and tear of the medical retinaculum (46 cases). All patients were available at follow-up, the average duration of follow-up was 18.2 months (ranging from 12-36 months). No infection, nerve and blood vessel injury, redislocation or other complications happened. Lysholm, Tegner and AAOS scores were used both preoper-atively and postoperatively, and LPA and LSD were compared. Statistically, the difference between these two scores was significant (P<0.05). The sport ability was improved among all patients. Conclusion Acute patellofemoral joint impingement syndrome can be treated effectively by modified suture of medial capsule and retinaculum structure combined with release of lateral retinacu-lum. The function of knee joint recovered well after operation with satisfactory objective and subjective effects. Key words: Arthroscopy; Patellar; Wounds and injuries