RESULTS OF MICROFRACTURE FOR ACETABULAR CHONDRAL DEFECTS AFTER SECOND LOOK ARTHROSCOPY

Abstract

Introduction: Chondral lesions are the second most common pathology encountered during hip arthroscopy and can cause substantial morbidity and functional limitation. Microfracture is a simple and effective technique to treat chondral lesions. Studies have shown good long term results in the knee. However there is little evidence to confirm the ability of microfracture to produce repair tissue in hip joint

Methods: Patients aged 18 years or older who had a full thickness acetabular chondral defect treated with microfracture during primary arthroscopy and who had a subsequent hip arthroscopy enabling visualisation of the treated chondral defect were included in the study. Over a three year period 185 patients had microfracture for treatment of full thickness chondral defect. 11 patients (8 males and 3 females) with a mean age of 35 years (range 17–54 years) who had revision hip arthroscopy for various reasons form the study population. The size of chondral defect was measured at the time of primary arthroscopy. Microfracture was performed using arthroscopic awls with a standard technique. Postoperatively a strict rehabilitation protocol was followed with no weight bearing allowed for six weeks. The extent and quality of repair tissue was assessed by visual inspection at second look arthroscopy

Results: All acetabular chondral lesions were identified in the antero-superior quadrant at primary arthroscopy. The average defect after debridement measured 180 mm2 (range 50–300 mm2). 10 patients had chondral lesions confined to the acetabulum. 1 patient had a large femoral head defect in addition, due to Avascular Necrosis. None of the patients had diffuse osteoarthritis. All patients had an associated labral tear. The mean time interval between the primary and revision arthroscopy was 12 months. Excluding 1 failure the overall percent fill of the defects was 95% (range 75 – 100%) with good quality (Grade 1) cartilage. There was one failure with only a 25% fill. In that particular patient a large flap of delaminated cartilage was not resected at primary arthroscopy. Instead microfracture was done under the flap in the hope of encouraging the cartilage to stick to the underlying bone. Unfortunately the cartilage continued to remain delaminated and also hindered the formation of new repair tissue.

Conclusion: Only one other series of second look arthroscopy after microfracture has been reported. Our series agrees with the results of those authors. These similar results from 2 centres confirm that arthroscopic microfracture is an effective treatment for acetabular chondral lesions in carefully selected patients.