Matharu Gulraj S, Blanshard Oliver, Dhaliwal Kawaljit, Judge Andrew, Murray David W, Pandit Hemant G
1Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Nuffield Orthopaedic Centre, University of Oxford, Oxford, United Kingdom 2MRC Lifecourse Epidemiology Unit, Southampton General Hospital, University of Southampton, Southampton, United Kingdom 3Leeds Institute of Rheumatic and Musculoskeletal Medicine, Chapel Allerton Hospital, Leeds, United Kingdom.
J Bone Joint Surg Am. 2017 Feb 1;99(3):214-222. doi: 10.2106/JBJS.16.00212.
The role of radiographs in the follow-up of patients with metal-on-metal hip resurfacing (MoMHR) implants is unclear. We investigated whether a combination of patient and radiographic factors predicted MoMHRs with evidence of a pseudotumor.
We performed a retrospective single-center case-control study of 384 MoMHRs. The pseudotumor group of 130 hips all had evidence of a symptomatic pseudotumor on cross-sectional imaging, with the diagnosis confirmed at revision. The nonpseudotumor group of 254 hips (a subgroup of these hips were previously reported on) all had normal findings on cross-sectional imaging. Radiographs taken immediately prior to revision were assessed in the pseudotumor group and were compared with radiographs taken at the time of normal cross-sectional imaging in the nonpseudotumor group. Two blinded independent observers analyzed the radiographs for signs of failure, with excellent interobserver agreement. Logistic regression modeling identified the patient and radiographic predictors of revision for pseudotumor.
Hips with a pseudotumor more commonly had abnormal findings on radiographs compared to hips without a pseudotumor (80.0% compared with 63.4%; p = 0.001). Patient and radiographic factors predictive of revision for pseudotumor in the multivariable model were female sex (odds ratio [OR], 3.14; 95% confidence interval [CI], 1.85 to 5.35; p < 0.001), high inclination (OR, 1.04 per degree; 95% CI, 1.01 to 1.07 per degree; p = 0.006), acetabular osteolysis (OR, 5.06; 95% CI, 2.14 to 12.0; p < 0.001), femoral osteolysis (OR, 17.8; 95% CI, 5.09 to 62.2; p < 0.001), and acetabular loosening (OR, 3.35; 95% CI, 1.34 to 8.35; p = 0.009). Factors predictive of not having a pseudotumor were anteversion of ≥5° (5° to <10°: OR, 0.31; 95% CI, 0.12 to 0.77; p = 0.012; and ≥10°: OR, 0.32; 95% CI, 0.15 to 0.70; p = 0.004) and heterotopic ossification (OR, 0.19; 95% CI, 0.05 to 0.72; p = 0.015). The final multivariable model was well calibrated (p = 0.589), with good discriminatory ability (area under the curve = 0.801; sensitivity = 74.4%; specificity = 71.7%).
A combination of patient and radiographic factors provided useful information for distinguishing between MoMHRs with and without evidence of a pseudotumor. Surgeons may wish to consider these specific patient and radiographic factors before proceeding with cross-sectional imaging. Radiographs are important when assessing patients with MoMHR implants and should be included in all follow-up protocols.
Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.
X线片在金属对金属髋关节表面置换（MoMHR）植入物患者随访中的作用尚不清楚。我们研究了患者因素和影像学因素的组合是否能预测出现假肿瘤迹象的MoMHR。
我们对384例MoMHR进行了一项回顾性单中心病例对照研究。130髋的假肿瘤组在横断面成像上均有症状性假肿瘤的证据，翻修时确诊。254髋的非假肿瘤组（这些髋中的一个亚组此前已有报道）在横断面成像上均有正常表现。对假肿瘤组翻修前立即拍摄的X线片进行评估，并与非假肿瘤组横断面成像正常时拍摄的X线片进行比较。两名独立的盲法观察者分析X线片是否有失败迹象，观察者间一致性良好。逻辑回归模型确定了假肿瘤翻修的患者和影像学预测因素。
与无假肿瘤的髋关节相比，有假肿瘤的髋关节在X线片上更常见异常表现（80.0% 对比63.4%；p = 0.001）。多变量模型中预测假肿瘤翻修的患者和影像学因素为女性（比值比[OR]，3.14；95%置信区间[CI]，1.85至5.35；p < 0.001）、高倾斜度（OR，每度1.04；95% CI，每度1.01至1.07；p = 0.006）、髋臼骨溶解（OR，5.06；95% CI，2.14至12.0；p < 0.001）、股骨骨溶解（OR，17.8；95% CI，5.09至62.2；p < 0.001）和髋臼松动（OR，3.35；95% CI，1.34至8.35；p = 0.009）。预测无假肿瘤的因素为前倾≥5°（5°至<10°：OR，0.31；95% CI，0.12至0.77；p = 0.012；≥10°：OR，0.32；95% CI，0.15至0.70；p = 0.004）和异位骨化（OR，0.19；95% CI，0.05至0.72；p = 0.015）。最终的多变量模型校准良好（p = 0.589），具有良好的辨别能力（曲线下面积 = 0.801；敏感性 = 74.4%；特异性 = 71.7%）。
患者因素和影像学因素的组合为区分有和没有假肿瘤迹象的MoMHR提供了有用信息。外科医生在进行横断面成像前可能希望考虑这些特定的患者和影像学因素。评估MoMHR植入物患者时X线片很重要，应纳入所有随访方案中。
诊断性III级。有关证据水平的完整描述，请参阅作者须知。
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