Exploring the Risk Factors for the Misdiagnosis of Osteonecrosis of Femoral Head: A Case-Control Study.

OBJECTIVE: The purpose of the present study was to evaluate the present situation and risk factors for the misdiagnosis of osteonecrosis of femoral head (ONFH), providing the basis for accurate diagnosis of ONFH.

METHODS: For this retrospective study, 1471 patients with ONFH were selected from the China Osteonecrosis of Femoral Head Database (CONFHD). These patients had been recruited between July 2016 and December 2018. According to whether or not they were misdiagnosed, the patients were divided into two groups, with 1168 cases (22-84 years old) included in the diagnosis group and 303 cases (21-80 years old) in the misdiagnosis group. Misdiagnosis was measured using the following criteria: (i) the patient had the same symptoms and signs, and the second diagnosis was not consistent with the initial diagnosis within 6 months; and (ii) the patient was admitted to a hospital participating in CONFHD and the previous diagnosis was inconsistent with the diagnosis given by the expert group. Comparisons of age, visual analogue scale for pain, and body mass index between the two groups were performed using a t-test. Gender, causes of ONFH, primary diseases requiring corticosteroids, methods of corticosteroid use, corticosteroid species, type of trauma, onset side of the disease, pain side, whether symptoms are hidden, and type of imaging examination at the initial visit were compared using the χ2 -test. Years of alcohol consumption, weekly alcohol consumption, and physician title at the initial visit were compared using a Mann-Whitney U-test. Furthermore, the statistically significant factors were evaluated using multiple regression analysis to investigate the risk factors of misdiagnosis.

RESULTS: A total of 303 patients (20.6%) were misdiagnosed: 118 cases were misdiagnosed as lumbar disc herniation, 86 cases as hip synovitis, 48 cases as hip osteoarthritis, 32 cases as rheumatoid arthritis, 11 cases as piriformis syndrome, 5 cases as sciatica, and 3 cases as soft-tissue injury. Whether symptoms are hidden (P = 0.038, odds ratio [OR] = 1.546, 95% confidence interval [CI] = 1.025-2.332), physician title at the initial visit (P < 0.001, OR = 3.324, 95% CI = 1.850-5.972), X-ray examination (P < 0.001, OR = 4.742, 95% CI = 3.159-7.118), corticosteroids (P < 0.001, OR = 0.295, 95% CI = 0.163-0.534), alcohol (P < 0.001, OR = 0.305, 95% CI = 0.171-0.546), and magnetic resonance imaging (MRI) examination (P = 0.042, OR = 0.649, 95% CI = 0.427-0.985) were each found to be associated with misdiagnosis.

CONCLUSION: Osteonecrosis of the femoral head is easily misdiagnosed as lumbar disc herniation, hip synovitis, hip osteoarthritis, and rheumatoid arthritis. Patient history of corticosteroid use or alcohol abuse and MRI examination at the initial diagnosis may be protective factors for misdiagnosis. Hidden symptoms, physician title at the initial visit (as attending doctor or resident doctor), and only X-ray examination at the initial diagnosis may be risk factors for misdiagnosis.