DO MODERN TECHNIQUES IMPROVE CORE DECOMPRESSION OUTCOMES FOR HIP OSTEONECROSIS?

Abstract

Introduction: Osteonecrosis of the femoral head is a devastating disease that often progresses to hip joint destruction necessitating total hip arthroplasty. The use of core decompression is typically recommended for patients with early small and medium-sized lesions. The reported efficacy of this procedure has been variable. Recently, various adjustments to the surgical technique have been described. There has been interest in performing multiple drillings under fluoroscopic guidance and combining core decompression with electrical stimulation and/or biological adjunctive growth factors. In order to assess whether the efficacy of this procedure has improved during the last 15 years using modern techniques, we compared recently reported radiographic and clinical success rates to results of surgeries performed prior to 1992. In addition, we evaluated the outcomes of our cohort of 52 patients (79 hips) who were treated with multiple small diameter drillings.

Method: A systematic review utilizing the Medline and Embase bibliographic databases found 59 studies meeting our inclusion criteria that were related to core decompression and osteonecrosis. The mean age for patients was 39 years (range, 9 to 83 years), and the mean follow-up was 56 months (range, 1 to 228 months). From these reports, there were 1,429 hips treated prior to 1992 and 1,957 hips since 1992. Other than the smaller percentage of Ficat stage III cases in the later studies, the reported etiologies and the stratification of preoperative Ficat stage were similar in the two strata of groups with the majority of patients being Ficat stage I and II and corticosteroids and alcohol being the most frequently reported associated diagnosis. From our institution, we identified 52 patients (79 hips) who had a core decompression utilizing a multiple small diameter (3 millimeters) technique at mean follow-up of 65 months. The outcome parameters collected for each core decompression patient at our institution and from the reports in literature were the number and percentage of patients who required additional surgeries, were clinical failures, or had radiographic progression of the disease.

Results: Overall, the success rates were higher for the studies that reported core decompressions performed during the last 15 years compared to procedures that were done prior to 1992. The proportion of patients surviving without additional surgery increased from 57% (range, 28 to 97%) in the earlier studies to 67% (range, 18 to 100%) in the more recent reports. Similarly, the radiographic success also increased from 54% (range, 0 to 94%) for the pre-1992 cohort to 59% (range, 22 to 90%). While clinical success increased from 57% (range, 28 to 94%) in the pre-1992 procedures to 61% (range, 29 to 90%) in reports from the last 15 years, this improvement was not statistically significant. Stratification by Ficat stage showed that there were significantly fewer patients who were Ficat stage III after 1992 suggesting that patient selection was the primary reason for the improvement in outcomes. For hips classified as Ficat stage II, there was an increase in clinical success and reduced percentage of patients requiring additional surgery in the more recent reports. The results of our cohort of patients were similar to other reports in the last 15 years. Patients who had small lesions and were Ficat stage I prior to treatment had the best results with 79% showing no radiographic progression.

Discussion: The results of the present study do not provide adequate evidence to suggest that recent techniques provide better clinical scores or radiographic outcomes. However, the additional accumulation of successful reports in the last decade confirms that core decompression is a safe and effective procedure for the treatment of early stages of osteonecrosis of the femoral head. Furthermore, these results suggest that proper patient selection can improve outcomes for this procedure. Based on the results of our experience as well as that of other studies, we will use core decompression to treat patients who have early small and medium-sized lesions and are Ficat stage I or II. Additionally, the mid-term follow-up of the multiple small diameter core decompression patients at our institution was longer than most studies, and had a success rate similar to, or higher than other reports, which confirms the use of this technique as the authors’ preferred method.