Long-term Outcome of Multiple Small-diameter Drilling Decompression Combined with Hip Arthroscopy versus Drilling Alone for Early Avascular Necrosis of the Femoral Head

Background： Avascular necrosis of femoral head （AVNFH） typically presents in the young adults and progresses quickly without proper treatments. However, the optimum treatments for early stage of AVNFH are still controversial. This study was conducted to evaluate the therapeutic effects of multiple small-diameter drilling decompression combined with hip arthroscopy for early AVNFH compared to drilling alone. Methods： This is a nonrandomized retrospective case series study. Between April 2006 and November 2010, 60 patients （98 hips） with early stage AVNFH participated in this study. The patients underwent multiple small-diameter drilling decompression combined with hip arthroscopy in 26 cases/43 hips （Group A） or drilling decompression alone in 34 cases/55 hips （Group B）. Patients were followed up at 6, 12, and 24 weeks, and every 6 months thereafter. Radiographs were taken at every follow-up, Harris scores were recorded at the last follow-up, the paired t-test was used to compare the postoperative Harris scores. Surgery effective rate of the two groups was compared using the Chi-square test. Results： All patients were followed up for an average of 57.6 months （range： 17-108 months）. Pain relief and improvement of hip function were assessed in all patients at 6 months after the surgery. At the last follow-up, Group A had better outcome with mean Harris＇ scores improved from 68.23 ± 11.37 to 82.07 ± 2.92 （t = -7.21, P = 0.001） than Group B with mean Harris＇ scores improved from 69.46 ± 9.71 to 75.79± 4.13 （t = -9.47, P = 0.037） （significantly different： t = -2.54, P = 0.017）. The total surgery effective rate was also significantly different between Groups A and B （86.0% vs. 74.5%; Z2 = 3.69, P = 0.02）. Conclusion： For early stage of AVNFH, multiple small-diameter drilling decompression combined with hip arthroscopy is more effective than drilling decompression alone.