Cho HS, et al. Yonsei Med J. 2024 Dec;66:e12. https://doi.org/10.3349/ymj.2024.0098

Pericapsular nerve group (PENG) block and periarticular injection (PAI) provide motor-sparing analgesia following hip surgery. We hypothesized that PAI offers non-inferior pain relief compared with PENG block in patients undergoing primary total hip arthroplasty (THA). In this randomized trial, 66 patients who underwent primary THA under spinal anesthesia were assigned to the PENG or PAI groups. The primary endpoint was the resting pain score 24 h postoperatively. The secondary endpoints included pain scores at rest and during movement at 6 and 48 h postoperatively, quadriceps strength at 24 h postoperatively, and opioid consumption at 24 and 48 h postoperatively. The mean difference in pain scores at rest between the two groups was 0.30 (95% confidence interval [CI], −0.78 to 1.39) at 24 h postoperatively. The upper 95% CI was lower than the non-inferiority margin, indicating non-inferior performance. No significant between-group differences were observed in the pain scores at 6 and 48 h postoperatively. Additionally, no significant differences in quadriceps strength and opioid consumption were observed between the two groups. The PAI and PENG blocks provided comparable postoperative analgesia during the first 48 h after primary THA. Further investigation is required to determine the optimal PAI technique and local anesthetic mixture.

Background: A postoperative radiograph in total hip arthroplasty (THA) is usually obtained to evaluate the inclination and anteversion of the acetabular components. However, there is no gold-standard method for calculating the exact inclination and anteversion of the acetabular components on post-THA radiographs. We aimed to measure the actual anteversion of the acetabular component on postoperative radiographs by obtaining correlation data between the virtual and actual acetabular component positioning using virtual three-dimensional (3D) surgery. Methods: A total of 64 hip scans of 32 patients who underwent lower-extremity computed tomography (CT) were retrospectively reviewed. We reconstructed 3D models of the 64 hips using customized computer software (Mimics). Furthermore, to identify the safe zone of acetabular component position in THA, we performed virtual 3D surgery simulations for five anteversion (−10°, 0°, 10°, 20°, and 30°) and five inclination (20°, 30°, 40°, 50°, and 60°) types. We analyzed the acetabular anatomy using 3D models to measure the radiographic, anatomical, and operative anteversion (RA, AA, OA) and inclination (RI, AI, OI) angles. Additionally, we used the Woo–Morrey (WM) method to calculate the anteversion angle in the reconstructed cross-table lateral (CL) radiographs and determined the correlation between these measurements. Results: The safe zone of the acetabular component was visualized on post-THA CL radiographs using the WM method of anteversion measurement based on the different anteversions and inclinations of the acetabular component. The AA, RA, OA, OI, and WM differed significantly between males and females (p value < 0.05). As the anatomical inclination or anteversion increased, the WM anteversion measurements also increased. The radiographic anteversion measurement best matched the WM method of measurement, followed by anatomical and operative methods. Conclusions: The actual anteversion of the acetabular component after THA can be measured on CL radiographs with the WM method using a 3D virtual program, with good reproducibility.

The effect of peripheral nerve block (PNB) according to leg lengthening following total hip arthroplasty (THA) has not been studied yet. The purpose of this study was to investigate the effect of PNB according to the change in leg length after THA. From January 2016 to August 2021, 353 patients who underwent unilateral THA for osteonecrosis of the femoral head or osteoarthritis of the hip joint were retrospectively reviewed. The patients were divided into two groups for comparison: 217 patients who controlled postoperative pain using only intravenous venous patient-controlled analgesia (IV PCA) (PCA group) and 136 patients who controlled postoperative pain using PNB and IV PCA (PCA + PNB group). We further divided the patients into two groups (leg lengthening after surgery < 10 mm and >10 mm) and compared them. After propensity score matching, the PCA and PCA + PNB groups, with 134 patients each, were compared and analyzed. The pain intensity at rest was significantly lower in the PCA + PNB group compared with that in the PCA group at postoperative 6, 24, and 48 h (p = 0.0001, 0.0009, and 0.05). PNB did not show superiority in terms of pain reduction in patients whose limb lengthening was more than 10 mm after THA. Further investigations on methods for reducing pain in patients whose leg length is increased by more than 10 mm are needed.