JOA - 2026-05-01 - Journal Article
Motor Nerve Palsy After Primary Total Hip Arthroplasty: A Case-Control Analysis With Radiographic Review.
Seward MW, Brown TS, Larson DR, Spinner RJ, Trousdale RT, Berry DJ, Abdel MP
Topics
Key Takeaway
Motor nerve palsy occurred in 0.4% of 10,604 primary THAs, with only 20% achieving complete recovery, and lumbar spine disease conferred a 21-fold increased odds of palsy (OR 21.3).
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Summary
This study determined the incidence, risk factors, and prognosis of motor nerve palsy within 90 days of primary THA across 10,604 procedures performed 2001–2014. Logistic regression and 1:2 case-control analysis identified limb lengthening (median 10 mm in cases vs. 3 mm in controls) and lumbar spine disease (OR 21.3, 95% CI 2.8–163.1) as the dominant risk factors. Complete motor recovery occurred in only 20% of affected patients at a mean of 28 weeks; age, sex, BMI, surgical approach, femoral offset, and cup inclination were not significant predictors.
Key Limitation
The confidence interval for the lumbar spine disease odds ratio spans nearly two orders of magnitude (2.8–163.1), indicating the risk estimate is statistically unstable due to small case numbers and limiting its direct clinical quantification.
Original Abstract
BACKGROUND
Motor nerve palsy is a serious complication after primary total hip arthroplasty (THA). This study determined the incidence, risk factors, and prognosis of motor nerve palsies after primary THAs in a large series with radiographic review.
METHODS
Among 10,604 primary THAs performed between 2001 and 2014, we identified 40 motor nerve palsies within 90 days of surgery. The mean patient age was 58 years (range, 17 to 88), 50% were women, and the mean body mass index was 31 (range, 18 to 50). Medical records were reviewed for confirmation of weakness, electromyography data, and surgical details. Logistic regressions and a 1:2 case-control analysis identified risk factors. Radiographic measurements were conducted for both groups. The mean follow-up was six years (range, 0.2 to 15).
RESULTS
Given the cohort of 10,604 primary THAs and 40 motor nerve palsies, the incidence was 0.4%. The peroneal branch of the sciatic nerve was most affected (68%), followed by the entire sciatic nerve (18%). The operative extremity was lengthened in 39 of 40 cases, with a median overall lengthening of 10 mm compared to three mm in controls. Only 20% of patients who had a nerve palsy had complete motor recovery, which occurred over a mean of 28 weeks (range, seven to 57). Age, sex, body mass index, operative time, surgical approach, femoral offset, and inclination were not significant risk factors. Patients who had lumbar spine disease had a 21-fold increased odds of nerve palsy (odds ratio 21.3, 95% confidence interval 2.8 to 163.1).
CONCLUSIONS
Motor nerve palsies following THA are rare (0.4%) but serious, as only 20% had complete recovery. The peroneal branch of the sciatic nerve was most commonly affected. A very strong risk factor was lumbar spine disease. Although the absolute risk of a motor nerve palsy was low, surgeons should consider comorbid spine conditions when weighing the risks of THA.