Hip Survival Rate in ONFH Patients After Transtrochanteric Rotational Osteotomy

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Hip Survival Rate in Patients with Avascular Necrosis of Femoral Head After Transtrochanteric Rotational Osteotomy: A Systematic Review and Meta-Analysis

Introduction

Osteonecrosis of the femoral head (ONFH) is a debilitating condition characterized by the death of bone cells due to compromised blood supply. Affecting over 8 million patients in China and leading to more than 500,000 hip replacements annually in the U.S., ONFH predominantly impacts young, active individuals. Total hip arthroplasty (THA), while effective for end-stage disease, poses challenges in younger populations due to prosthetic wear and loosening. Consequently, joint-preserving interventions like transtrochanteric rotational osteotomy (TRO) have gained attention. Developed by Sugioka in 1972, TRO repositions viable bone to the weight-bearing area of the femoral head, aiming to prevent collapse and delay THA. Despite promising outcomes in Japanese studies, American and European trials reported higher failure rates, creating clinical controversy. This meta-analysis evaluates 5- and 10-year hip survival rates post-TRO, stratifying results by geographic populations and endpoints (conversion to arthroplasty vs. radiographic failure).

Methods

Study Design and Eligibility

A comprehensive search of seven databases (PubMed, Web of Science, Embase, Cochrane Library, VIP, CNKI, Wan Fang) identified 19 studies (15 cohort, 4 case-control) meeting inclusion criteria. Studies required Kaplan-Meier survival data or raw data for calculating survival rates, with follow-up ≥5 years. Exclusion criteria included case reports, reviews, non-Sugioka techniques, and insufficient follow-up.

Data Extraction and Analysis

Two independent reviewers extracted data, including patient demographics, surgical techniques (anterior/posterior TRO), survival endpoints, and clinical scores. Methodological quality was assessed using the Newcastle-Ottawa Scale (NOS). Two statistical approaches were employed:

  • Method 1: Applied when sample sizes were sufficient ((n cdot P) and (n cdot [1-P] > 5)), calculating risk difference (RD) with 95% confidence intervals (CI).
  • Method 2: Used for smaller cohorts or zero-event studies, estimating odds ratios (OR) transformed into pooled rates.

Subgroup analyses compared Asian vs. non-Asian populations due to outcome disparities. Sensitivity analyses and funnel plots assessed heterogeneity and publication bias.

Results

Patient and Study Characteristics

The 19 studies (1992–2019) included 1,125 hips, predominantly male (70%), with mean ages 28–42 years. Etiologies spanned steroid use (38%), alcohol (32%), trauma (14%), and idiopathic causes (16%). Most studies utilized anterior TRO (ARO, 75%), with Japanese Investigation Committee (JIC) or ARCO staging guiding patient selection. Follow-up ranged from 4.4 to 24.6 years.

Hip Survival Rates: Conversion to Arthroplasty

5-Year Survival

  • Asian Population (Method 1): Pooled survival rate was 86% (95% CI: 82–89%, (I^2 = 0%)), from 395 hips.
  • Non-Asian Population (Method 1): Survival rate dropped to 55% (95% CI: 43–67%, (I^2 = 36%)), based on 127 hips.
  • Method 2 Analysis: Combining 152 hips, survival was 90% (95% CI: 79–95%, (I^2 = 11%)).

Case-control studies ((n = 292)) showed 72% survival (95% CI: 53–91%, (I^2 = 96%)), though heterogeneity was high due to diverse controls.

10-Year Survival

  • Asian Population (Method 1): Survival declined to 72% (95% CI: 65–78%, (I^2 = 0%)), from 204 hips.
  • Non-Asian Population (Method 1): Rate fell to 42% (95% CI: 28–55%, (I^2 = 71%)).
  • Method 2 Analysis: Aggregate 10-year survival was 89% (95% CI: 81–94%, (I^2 = 0%)).

Radiographic Failure as Endpoint

5-Year Survival

Pooled data from 206 hips (Method 1) showed 70% survival (95% CI: 64–76%, (I^2 = 8%)).

10-Year Survival

Two studies ((n = 158)) reported 53% survival (95% CI: 46–61%, (I^2 = 40%)).

Clinical Outcomes

Merle d’Aubigné scores (excellent/good) at final follow-up averaged 66% (95% CI: 47–86%, (I^2 = 83%)), indicating moderate functional improvement despite radiographic deterioration.

Discussion

Geographic Disparities

Asian cohorts demonstrated superior survival rates (86% vs. 55% at 5 years), potentially due to stricter patient selection, surgical expertise, and earlier intervention. Japanese studies emphasized precise intact ratio calculations (>34%) and meticulous preservation of the medial femoral circumflex artery, reducing post-TRO collapse. Conversely, non-Asian studies reported higher early failures, possibly from broader inclusion criteria (e.g., advanced ARCO stages) and technical variability.

Surgical and Technical Considerations

Prognostic factors influencing TRO success include:

  1. Preoperative Stage: Survival rates plummeted in ARCO/JIC Stage III/IV vs. Stage II (65% vs. 82%).
  2. Fixation Methods: Transition from screws to locking plates reduced non-union rates from 15% to <5%.
  3. Intact Ratio: Post-TRO viable bone >34% correlated with 89% 10-year survival vs. 52% for <34%.

Limitations and Heterogeneity

High heterogeneity ((I^2 > 75%)) in case-control analyses stemmed from variable controls (conservative management vs. bone grafting). Small sample sizes in non-Asian studies ((n = 18–26)) limited statistical power. Additionally, lack of randomized trials and long-term data beyond 20 years warrants caution.

Conclusion

Transtrochanteric rotational osteotomy offers a viable hip-preserving option for ONFH, particularly in Asian populations with careful patient selection and surgical precision. While 5- and 10-year survival rates (86% and 72%) are encouraging, non-Asian outcomes highlight the need for standardized protocols. Future RCTs addressing ethnicity, fixation techniques, and postoperative management are critical to optimize TRO’s global applicability.

doi.org/10.1097/CM9.0000000000000562

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