Reduction of posterior dislocated hip prosthesis using a modified lateral position maneuver: a retrospective, clinical comparative, and follow-up study

BACKGROUND: Posterior dislocation (PD) is a common complication after total hip arthroplasty (THA), and the Allis maneuver is the most widely used method for reduction. However, this classic maneuver has some disadvantages. The aim of the present study was to investigate whether a modified lateral position (MLP) reduction maneuver provides an easier and safer method for PD reduction than the Allis maneuver. METHODS: Between August 2019 and September 2021, a series of 88 consecutive PD patients who underwent THA were retrospectively evaluated. The patients were divided into the MLP reduction group and Allis reduction group according to the electronic health medical record. The success rate of closed reduction, Harris hip score (HHS), and radiographic outcomes were determined. Satisfaction scores, doctor safety events and complications were also determined and compared between the groups. The mean follow-up period was 1.66 ± 0.88 years. RESULTS: The success rate of reduction in the MLP group was significantly 12.5% higher than that in the Allis group (P = 0.024). Periprosthetic fracture and implant loosening were retrospectively identified in 2 hips and 1 hip, which all occurred in the Allis group. The mean doctor and patient SAPS scores in the MLP group were 84.00 points and 76.97 points, respectively, which were significantly higher than those in the Allis group (72.12, P = 0.008 and 63.28 points, P = 0.001). Four adverse events were reported in the Allis group, compared with 0 in the MLP group. CONCLUSIONS: For PD after THA, the MLP reduction maneuver can effectively increase the reduction success rate, satisfaction, and doctor safety without increasing the risk of complications compared with the traditional Allis supine reduction maneuver. TRIAL REGISTRATION: This study was registered in the Chinese Clinical Trial Registry (ChiCTR2100054562) in December 19th 2021.