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.

Effect of hip dysplasia on the development of the femoral head growth plate.

Purpose: The purpose of this study was to observe whether developmental dysplasia of the hip (DDH) affects the development of the femoral head growth plate and to analyze the risk factors. Methods: We selected female patients aged between 11 and 20 years with unilateral DDH and unclosed femoral head growth plate (s). The selected patients underwent anteroposterior radiography of the hip joint to compare the degree of development of the femoral head growth plate on both sides and to identify risk factors that affect the development of the growth plate in the femoral head. Results: We included 48 female patients with unilateral DDH, with an average age of 14 years (range: 11.1-18.5 years) and an average BMI of 20.4 kg/m² (range: 15.5 kg/m²-27.9 kg/m²). Among them, 23 patients had earlier development of the femoral head growth plate on the affected side than on the healthy side, while the degree of development of the femoral head growth plate in 25 patients was the same as that on the contralateral side. When the Tönnis angle was greater than 29.5°C and/or the Reimers migration index was greater than 48.5%, there was a statistically significant difference in the acceleration of femoral head growth plate development. Conclusion: An abnormal relative position of the acetabulum-femoral head caused by DDH can accelerate closure of the femoral head growth plate in immature female patients. The risk factors are a Tönnis angle greater than 29.5°C and/or Reimers migration index greater than 48.5%.

Determining anterior hip coverage in patients with hip dysplasia using the anterior center-edge angle on Lequesne's false-profile radiograph and on computed tomography.

Anterior hip coverage is important for hip stability. As a parameter of anterior hip coverage, the anterior center-edge angle on false-profile radiograph (ACEA FP) is associated with clinical outcomes. With the widespread application of computed tomography (CT), the anterior center-edge angle on CT (ACEA CT) has also been used to measure anterior hip coverage. Little is known about the reproducibility of the ACEA FP and ACEA CT in patients with hip dysplasia or the correlation between the ACEA CT and ACEA FP. In total, 49 hips of 49 patients who underwent periacetabular osteotomy in our center were included. The lateral center-edge angle, Tönnis angle, ACEA FP and ACEA CT were determined. We assessed the intraobserver and interobserver reliability of the ACEA FP and ACEA CT, the effect of the Tönnis angle on the reliability of the ACEA FP and ACEA CT and the correlation between the ACEA CT and ACEA FP. The intraobserver and interobserver interclass correlation coefficients of the ACEA FP were good, and those of the ACEA CT were very good. The Tönnis angle was weakly correlated with inconsistent ACEA FP measurements (P = 0.008) but not with inconsistent ACEA CT measurements (P = 0.600). No correlation between ACEA FP and ACEA CT measurements was observed (P = 0.213-0.665). The reproducibility of the ACEA CT is more consistent than that of the ACEA FP. The oblique acetabular roof had an effect on determining the ACEA FP but not on determining the ACEA CT. No correlation was observed between the measured ACEA FP and ACEA CT values, so the clinical evidence obtained from the ACEA FP cannot be directly applied to the ACEA CT.

Can we determine anterior hip coverage from pelvic anteroposterior radiographs? A study of patients with hip dysplasia.

PURPOSE: Insufficient coverage causes hip joint instability and results in hip pain. Anterior hip coverage can be determined on both pelvic anteroposterior (AP) radiographs and false profile (FP) radiographs. Four parameters are commonly used to determine the anterior coverage on pelvic AP radiographs: the crossover index, crossover sign, anterior wall index (AWI), and rule of thirds. This study aims to clarify the relationship between these 4 parameters on AP radiographs and the anterior center edge angle (ACEA) on FP radiographs. METHODS: In this study, 53 patients who underwent periacetabular osteotomy for hip dysplasia at our center between July 2020 and October 2020 were retrospectively reviewed. Four parameters on AP radiographs and the ACEA on FP radiographs before surgery and 6 months after surgery were measured and compared for each hip. RESULTS: Upon examining the 53 hips in this study, there was no correlation between either the crossover index and the ACEA (P = 0.66) or the crossover sign before surgery. The postoperative correlation between the crossover index and the ACEA was weak (r = 0.36, P = 0.007), and that between the crossover sign and the ACEA was moderate (r = 0.41, P = 0.003). There was a weak correlation between the AWI and ACEA both before (r = 0.288, P = 0.036) and after (r = 0.349, P = 0.011) the operation. Evaluation of the anterior coverage by the rule of thirds was also not consistent when determining the anterior coverage with the ACEA. CONCLUSION: Anterior coverage on AP radiographs is largely inconsistent with ACEA on FP radiographs, especially before the surgery. It is recommended to take FP radiographs routinely for determining anterior hip coverage.

Periacetabular osteotomy for Tönnis grade 2 osteoarthritis secondary to hip dysplasia.

PURPOSE: To investigate the clinical outcomes of periacetabular osteotomy (PAO) for Tönnis grade 2 osteoarthritis secondary to hip dysplasia. METHODS: Forty-nine patients (51 hips) with Tönnis grade 2 osteoarthritis secondary to hip dysplasia, followed by a mean of 52.3 months (range: 24.1 to 95.2 months), were reviewed. As a control group, 51 patients (51 hips) with Tönnis grade 1 osteoarthritis were matched for age, surgery date, and follow-up period. All patients were evaluated clinically with the use of modified Harris hip score (mHHS) questionnaire, WOMAC score, and the 12-item International Hip Outcome Tool (iHot-12). Radiographic measurements included the lateral centre-edge angle (LCEA), Tönnis angle, and anterior centre-edge angle (ACEA). Kaplan-Meier survivorship analysis was performed to predict a five year survival rate of no osteoarthritis progression. RESULTS: All functional scores and radiographic measurements of the two groups significantly improved at the final follow-up. There were no significant differences between the two groups either in functional scores or radiographic measurements. The five year survival rate of no osteoarthritis progression was 86.2% in Tönnis grade 2 group and 93.1% in Tönnis grade 1 group, respectively. In the Tönnis grade 2 group, the osteoarthritis progressed in six hips. Of which, four hips had an ACEA of < 25°. No osteoarthritis progression was found in hips with an ACEA > 40°. CONCLUSIONS: PAO yielded similar results for patients with Tönnis grade 2 and grade 1 osteoarthritis secondary to hip dysplasia. The majority of hips can be preserved without progression of osteoarthritis at five years postoperatively. The slight overcorrection anteriorly may be helpful in preventing osteoarthritis progression.

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.

[Effects of femoral offset and mechanical axis of the lower extremity on hip after osteotomy for adult developmental dysplasia of the hip].

OBJECTIVE: To investigate the effects of femoral offset and mechanical axis of the lower extremity on hip after osteotomy for adult developmental dysplasia of the hip (DDH). METHODS: A clinical data of 62 adult patients with DDH (62 hips), who underwent periacetabular osteotomy combined with femoral osteotomy between January 2016 and May 2019 and met selective criteria, was retrospectively analyzed. There were 6 males and 56 females. The age ranged from 18 to 38 years, with an average of 24.4 years. Body mass index ranged from 15.8 to 31.8 kg/m 2, with an average of 21.8 kg/m 2. There were 44 cases of Hartofilakidis typeⅠ and 18 cases of typeⅡ. According to the modified Tönnis osteoarthritis staging, 46 cases were stage 0 and 16 cases were stageⅠ. There were 13 cases with pelvic anteversion, 40 cases with normal pelvis, and 9 cases with pelvic retroversion. Intraoperative blood loss, length of hospital stay, and complications were recorded. Postoperative hip function was evaluated by Harris score and International Hip Outcome Tool (iHOT) score. The femoral offset, collo-diaphyseal angle, hip-knee-ankle angle (HKA), knee valus angle, CE (Wiberg central-edge angle), anterior CE angle, and acetabular index angle were measured and the osteotomy healing was observed on X-ray films. Patients were grouped according to postoperative femoral offset (≥48 mm or <48 mm) and HKA [varus group (HKA<177°), normal group (HKA 177°-183°), and valgus group (HKA>183°)]. Harris score and iHOT score were compared between groups. RESULTS: Intraoperative blood loss ranged from 200 to 1 550 mL, with an average of 476 mL. The length of hospital stay ranged from 8 to 21 days, with an average of 13.3 days. All incisions healed by first intention. All patients were followed up 2.0-4.5 years, with an average of 2.8 years. At 1 year after operation, the Harris score and iHOT score of the hip joint significantly increased when compared with those before operation ( P<0.05); there were significant differences in the femoral offset, collo-diaphyseal angle, HKA, knee valus angle, CE angle, anterior CE angle, and acetabular index angle between pre- and post-operation ( P>0.05). According to the modified Tönnis osteoarthritis staging, 38 cases were stage 0 and 24 cases were stageⅠ; and there was no significant difference between pre- and post-operation ( χ 2=2.362, P=0.124). There were 11 cases with pelvic anteversion, 38 cases with normal pelvis, and 13 cases with pelvic retroversion, showing no significant difference when compared with that before operation ( χ 2=0.954, P=0.623). The pubic branch osteotomy did not heal in 9 cases, proximal femur osteotomy did not heal in 2 cases, and inferior pubic ramus stress fracture occurred in 5 cases. There were significant differences ( P<0.05) in the Harris score and iHOT score between femoral offset≥48 mm group ( n=10) and femoral offset<48 mm group ( n=52). There was no significant difference ( P>0.05) in Harris score and iHOT score between varus group ( n=13), normal group ( n=40), and valgus group ( n=9). CONCLUSION: Periacetabular osteotomy combined with femoral osteotomy can improve the femoral offset and mechanical axis of the lower extremity of patients with DDH, and improve the functional score of the hip. However, excessive increase of femoral offset during femoral osteotomy is not desirable, resulting in low postoperative functional score.

Effects of Hindlimb Unweighting on MBP and GDNF Expression and Morphology in Rat Dorsal Root Ganglia Neurons.

With the development of technology and space exploration, studies on long-duration space flights have shown that microgravity induces damage to multiple organs, including the dorsal root ganglia (DRG). However, very little is known about the effects of long-term microgravity on DRG neurons. This study investigated the effects of microgravity on lumbar 5 (L5) DRG neurons in rats using the hindlimb unweighting (HU) model. Male (M) and female (F) Sprague-Dawley rats were randomly divided into M- and F-control (CON) groups and M- and F-HU groups, respectively (n = 10). At the end of HU treatment for 4 weeks, morphological changes were detected. Myelin basic protein (MBP) and degenerated myelin basic protein (dgen-MBP) expressions were analyzed by immunofluorescence and western blot assays. Glial cell line-derived neurotrophic factor (GDNF) protein and mRNA expressions were also analyzed by immunohistochemistry, western blot, and RT-PCR analysis, respectively. Compared with the corresponding CON groups, the HU groups exhibited slightly loose junctions between DRG neurons, some separated ganglion cells and satellite cells, and lightly stained Nissl bodies that were of smaller size and had a scattered distribution. High levels of dgen-MBP and low MBP expressions were appeared and GDNF expressions were significantly decreased in both HU groups. Changes were more pronounced in the F-HU group than in the M-HU group. In conclusion, HU treatment induced damage of L5 DRG neurons, which was correlated with decreased total MBP protein expression, increased dgen-MBP expression, and reduced GDNF protein and mRNA expression. Importantly, these changes were more severe in F-HU rats compared with M-HU rats.