Is Prior Nonoperative or Operative Treatment of Dysplasia of the Hip Associated With Poorer Results of Periacetabular Osteotomy?

BACKGROUND: Understanding the implications of either nonoperative or operative treatment of developmental dysplasia of the hip (DDH) performed before periacetabular osteotomy (PAO) is critical to counseling patients and their families. There are limited studies, however, on PAO for the treatment of residual DDH after surgical intervention during childhood, and even less information about PAO after prior nonoperative treatment. QUESTIONS/PURPOSES: We analyzed patients who had undergone PAO for DDH and asked: Did patients with prior childhood treatment (either operative or nonoperative) (1) improve less in modified Harris hip score (mHHS), 12-item International Hip Outcome Tool (iHOT-12) score, or WOMAC score; (2) demonstrate more severe preoperative deformities; and (3) receive less complete radiographic correction and have more frequent complications than did patients whose hips had not undergone prior treatment? We also asked: (4) Were there subgroup differences among patients with DDH treated nonoperatively versus operatively before PAO in these same functional and radiographic parameters? METHODS: Between January 2011 and December 2020, a total of 90 PAOs were performed in 82 patients who had prior surgical or nonsurgical treatment. Of those, 3 patients (3 hips) with neuromuscular diseases were excluded, 4 patients (5 hips) were excluded for having received treatment after childhood, 7 hips that had undergone bilateral PAOs were excluded, and another 4 patients (4 hips) were lost to follow-up before the minimum study period of 2 years, leaving 71 patients (71 hips) for analysis (the previous treatment group). Among these, 32 patients had a history of previous surgery (the previous surgery group), and 39 patients had prior nonsurgical treatment (such as a Pavlik harness, closed reduction, spica casting) (the previous nonoperative group). During the same period, 1109 PAOs were performed in 956 patients who had no history of previous hip treatment. Following a 1:2 ratio, 142 patients (142 hips) were selected as the control group by matching for age (within 2 years difference), year of surgery (same year), and follow-up time (within 1-year difference). The patient characteristics for both the previous treatment group and the control group exhibited comparability, with mean ± SD follow-up durations of 49 ± 23 months and 48 ± 19 months, respectively. Within the previous 5 years, 3 patients (8%) in the previous nonoperative group, 4 patients (13%) in the previous surgery group, and 15 patients (11%) in the control group had not attended follow-up visits. We compared hip function and radiographic results between the two groups and performed a subgroup analysis between the previous surgery group and the previous nonoperative group. Hip function was assessed using the mHHS questionnaire, the WOMAC, and the iHOT-12 with attention to the minimum clinically important differences of these tools. The threshold values for clinically important improvement were 9.6 points, 13 points, and 16.1 points for the mHHS, iHOT-12, and WOMAC, respectively. Radiographic measurements included the lateral center-edge angle (LCEA), anterior center-edge angle (ACEA), Tönnis angle, acetabulum-head index, and acetabular wall index. We also evaluated Tönnis osteoarthritis grade and femoral head deformity. Occurrences of adverse radiographic events such as posterior column fracture, nonunion, stress fractures, insufficient coverage or overcoverage, acetabular protrusion, and progression of osteoarthritis were recorded. RESULTS: We found no clinically important differences in magnitude of improvement between the previous treatment group and the control group in terms of mHHS (mean ± SD 10 ± 12 versus 12 ± 12; p = 0.36), iHOT-12 (25 ± 18 versus 26 ± 19; p = 0.51), or WOMAC score (12 ± 12 versus 15 ± 19; p = 0.17). Preoperative deformity in the previous treatment group was more severe than in the control group (mean ± SD LCEA -1° ± 9° versus 5° ± 8°; ACEA -8° ± 18° versus 1° ± 14°; Tönnis angle 31° ± 7° versus 27° ± 7°; acetabulum-head index 56% ± 13% versus 61% ± 8%; all p < 0.001). In the previous treatment group, a higher percentage of patients exhibited flattening or irregularity of the femoral head compared with the control group (52% versus 9%; p < 0.001), and there was also a higher proportion of patients with Tönnis grade 1 or above (51% versus 42%; p < 0.001). Although there were still differences in LCEA, ACEA, and Tönnis angle between the two groups at the last follow-up, the differences were small, and the mean values were within the normal range. The previous treatment group had a higher risk of intraoperative posterior column fracture (14% and 5%; p = 0.02), insufficient acetabular coverage (20% and 8%; p = 0.01), and progression of osteoarthritis (17% and 8%; p = 0.04) compared with the control group. Subgroup analysis revealed no clinically important differences in magnitude of improvement between the previous surgery group and the previous nonoperative group in terms of mHHS (10 ± 14 versus 10 ± 11; p = 0.91), iHOT-12 (22 ± 21 versus 27 ± 14; p = 0.26), or WOMAC score (12 ± 14 versus 12 ± 11; p = 0.94). Apart from a higher proportion of patients who presented with arthritis (72% versus 34%; p = 0.01) and a smaller anterior wall index (11% ± 11% versus 20% ± 12%; p = 0.01) in the previous surgery group, all other preoperative radiographic parameters were consistent between the two groups. Additionally, the previous surgery group had a higher frequency of arthritis progression (28% versus 8%; p = 0.02), while the frequencies of other complications were similar between the two groups. Specifically, the frequencies of pubic ramus nonunion (22% versus 21%; p = 0.89), intraoperative posterior column fracture (19% versus 10%; p = 0.50), and insufficient acetabular coverage (25% versus 15%; p = 0.31) were high in both groups. CONCLUSION: We found no clinically important difference in the magnitude of improvement between patients who had childhood treatment and those who did not, but patients who had prior childhood treatment were more likely to experience serious complications, and radiographic correction in those patients was less complete. As in the case of patients who have had prior operative treatments, it is crucial not to overlook the unexpectedly severe deformity of residual DDH after previous nonoperative treatment and complications following PAO. Surgeons and patients alike should be aware of the potential for worse radiographic outcomes or an increased risk of complications when prior operative or nonoperative treatment has preceded PAO. Future studies might investigate optimal management strategies for this specific group of patients to improve outcomes and reduce complications. LEVEL OF EVIDENCE: Level III, therapeutic study.

Comparison of Anterior Center-Edge Angle Measured From the Acetabular Sourcil Versus the Anterior Bone-Edge of the Acetabulum: A Descriptive Laboratory Study.

Background: Measuring anterior hip coverage on false-profile (FP) radiographs is important for judging anterior hip coverage. Conventionally, the anterior center-edge angle (ACEA) is measured from the anterior edge of the acetabular sourcil (sourcil ACEA); however, the anterior bone edge is also used as the anterior landmark. Purpose: To determine whether the sourcil ACEA or the bone-edge ACEA better represents the anterior coverage of the hip joint. Study Design: Descriptive laboratory study. Methods: We retrospectively observed 49 hips in 49 patients who underwent isolated periacetabular osteotomy. The sourcil ACEA was measured according to the standard procedure. Then, 3-dimensional (3D) volumetric models were made from computed tomographic data. The acetabular surface of the 3D model was labeled and projected onto a simulated FP radiograph, enabling the edge of the acetabulum to be identified. This simulated FP radiograph was used to measure the "true ACEA," as well as the sourcil ACEA and the bone-edge ACEA, and the 3 measurements were compared. Statistical analysis was performed-including testing for normal distribution, measuring interobserver agreement, evaluating differences between measurements, and validating correlation. Results: The mean sourcil ACEA was 8.6° (range, -3.9° to 31.7°) smaller than that of the true ACEA (P < .001); there was a strong correlation (r = 0.81; P < .001) between the 2. The mean bone-edge ACEA was 16.8° (range, -1.7° to 45.4°) greater than that of the true ACEA (P < .001); there was a moderate correlation (r = 0.57; P < 0.001) between the 2. Conclusion: Both the sourcil ACEA and bone-edge ACEA differed from the true ACEA. However, compared with the bone-edge ACEA, the sourcil ACEA was numerically closer to the true ACEA and had a stronger correlation with it . Clinical Relevance: While the exact edge of the true bearing surface of the articular cartilage may not be visible on the FP radiograph, the sourcil ACEA can be effectively utilized as a reliable surrogate when evaluating the anterior acetabular coverage in hip preservation surgery.

The modified capsular arthroplasty for young patients with developmental dislocation of the hip.

The present study aimed to investigate the clinical results of the modified Codivilla-Hey Groves-Colonna capsular arthroplasty in the treatment of young patients with developmental dislocation of the hip. We retrospectively evaluated 90 patients (92 hips) who underwent the modified capsular arthroplasty from June 2012 to June 2021. Hips were evaluated using the modified hip Harris score (mHHS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and the 12-item International Hip Outcome Tool (iHOT-12). The Tönnis osteoarthritis grade and the Severin classification system were used to assess the radiographic outcomes. The average age was 15.7 years (range: 8-26 years). The mean pre-operative mHHS, the WOMAC score and the iHOT-12 score were 83.03, 14.05 and 52.79, respectively. The patients were followed for a mean of 41.1 months (range: 12.1-120.9 months). The patients had a mean mHHS of 83.61 (range: 31.2-97), a WOMAC score of 16.41 (range: 0-51) and an iHOT-12 score of 64.81 (range: 12.9-98.2) at the final follow-up. Capsular thickness had a positive predication on the final functional outcomes. The excellent/good rate of radiological reduction was 79.3%. More than 60% of patients had no/slight osteoarthritis. A total of 54 hips (58.7%) had superior radiographic outcomes. The risk factors for inferior radiographic outcomes were capsular quality (odds ratio [OR]: 0.358, 95% confidence interval [CI]: 0.113-0.931) and capsular thickness (OR: 0.265, 95% CI: 0.134-0.525). Joint stiffness was the most common complication (14.1%). We confirmed the efficacy of this procedure in the treatment of developmental hip dislocation. Patients with poor capsular quality are not suitable for this procedure. With suitable selection according to indications, this procedure can restore the hip rotation center with a low incidence of femoral head necrosis or severe osteoarthritis.