Eccentric Rotational Acetabular Osteotomy Research Articles

Risk factors for lateralization or superiorization of the center of the femoral head in eccentric rotational acetabular osteotomy

PurposeThis study aimed to clarify the factors that cause the lateralization and superiorization of the femoral head after eccentric rotational acetabular osteotomy (ERAO) by examining the three-dimensional morphology of the osteotomy site using computed tomography (CT). MethodsThis study included 52 patients who underwent ERAO for hip dysplasia. Postoperatively, the center of the femoral head was measured for lateralization and superiorization. We defined the iliac and sciatic osteotomy angles in the coronal and axial CT planes, respectively. The surgical factors for lateralization and superiorization were analysed using multiple logistic regression analysis. We also analysed the relationship between the femoral head relocation and clinical outcomes (as assessed using Japanese Orthopaedic Association (JOA) scores). ResultsThirty-five patients had hips with lateralized femoral heads, and 25 patients’ femoral heads were superiorized. Logistic regression analysis revealed that a higher osteotomy angle of the ilium in the coronal plane served as a significant predictor of superiorization of the femoral head. Similarly, a larger osteotomy angle of the ischium in the axial plane and the amount of change in the lateral centre edge angle were identified as predictors of lateralization. A weak negative correlation was observed between the amount of lateralization and the JOA score. ConclusionLarge osteotomy angles in the superior and posterior aspects of the acetabulum carry a risk of superiorization and lateralization of the center of the femoral head. Surgeons should be aware of the need to chisel through the internal plate to achieve the results described in the ERAO theory. Study designA single-center, retrospective study.

Factors affecting return to sports after eccentric rotational acetabular osteotomy

BackgroundAlthough eccentric acetabular rotation osteotomy (ERAO) is an effective treatment for developmental dysplasia of the hip (DDH), there is little information about return to sports after ERAO. This study aimed to investigate 1) the patient factors that influence the return to sports after ERAO, 2) whether postoperative sports participation will affect future osteoarthritis progression. HypothesisSome factors affect the return to sports after ERAO. Patients and methodsOf 503 patients who underwent ERAO from 1990 to 2010, 124 who had been continuously participating in sports preoperatively (average 13.2 years after surgery) were included. Patient demographics of sex, age, body mass index, unilateral to bilateral case ratio, history of treatment for childhood DDH, preoperative Kellgren-Lawrence (KL) grade, center edge angle, joint congruency, Harris hip score, complications and the survival rate were compared between the S group (patients who participated in the same sports preoperatively) and N group (patients who could not participate in sports postoperatively). ResultsSeventy-two (58%) and 52 patients (42%) in the S and N groups, respectively, had an overall return to sports rate of 64% (79 patients). The most common sports that patients participated in were swimming (30 patients [24%]), jogging (12 [10%]), and golf (10 [8%]) preoperatively, and swimming (14 patients [11%]), golf (8 [6%]), and jogging (8 [6%]) postoperatively. There were no significant differences between both groups in terms of sex, age, body mass index, unilateral to bilateral case ratio, history of treatment for childhood DDH, preoperative KL grade, and joint congruency. There was a significant difference in patient factors between the S (11 joints [14%]) and N (20 joints [38%]) groups only when the preoperative center edge angle was <0°. There was no significant difference in the preoperative Harris hip score and the final survey between the S (73.2±4.6 and 93.4±7.2) and N (72.5±4.8 and 92.1±7.4) groups. Complications showed no significant differences between the five patients (7%) in the S group and six patients (13%) in the N group. The KL grade progressed in 10 cases (grade II to III in 2 cases and grade III to IV in 8) in the S group and 8 cases (grade II to III in 1 case and grade III to IV in 7 cases) in the N group. The 10-year and 20-year joint survival rates with THA conversion as the endpoint were 98.1% (95% CI: 87.4%–99.7%) and 83.7% (95% CI: 62.6%–93.4%) in the S group and 100% (95% CI: 70.7%–99.3%) and 95.2% (95% CI: 12.6%–92.6%) in the N group, respectively. In the evaluation of factors affecting sports return by logistic regression analysis, only one significant factor (odds ratio 3.42, 95% confidence interval: 1.58–7.42, p<0.01) was the preoperative center edge angle <0°. DiscussionThe chief factor affecting the return to sports after surgery was a preoperative center edge angle <0°; moreover, the continuation of sports did not affect the subsequent progression of osteoarthritis or THA conversion. Level of evidencelevel III, cohort study.

Pelvic osteotomies for acetabular dysplasia: Are there outcomes, survivorship and complication differences between different osteotomy techniques?

The purpose of this study was to evaluate the safety and efficacy of Periacetabular osteotomy (PAO), rotational acetabular osteotomy (RAO), and eccentric rotational acetabular osteotomy (ERAO) for treating hip dysplasia by comparing complication rates, survivorship, and functional outcomes after treatment. A systematic review in the MEDLINE and CINAHL databases was performed, and studies reporting outcomes after pelvic osteotomy for hip dysplasia with a minimum of 1-year follow-up or reported postoperative complications was included. Patient demographics, radiographic measurements, patient reported outcomes including the modified Harris hip score (mHHS), complications using the modified Clavien-Dindo classification, and reoperations were extracted from each study. A meta-analysis of outcome scores, complications, change in acetabular coverage, and revision rates for the 3 pelvic osteotomies was performed. A total of 47 articles detailing outcomes of 6,107 patients undergoing pelvic osteotomies were included in the final analysis. When stratified by procedure, RAO had a statistically greater change in LCEA when compared to PAO (33.9° vs 18.0°; P <0.001). The average pooled mHHS improvement was 15.6 (95% CI: 8.3–22.8, I2= 99.4%). Although ERAO had higher mean score improvements when compared to RAO and PAO, the difference was not statistically significant (P >0.05). Lastly, patients undergoing PAO had a statistically greater complication rate than those undergoing ERAO and RAO (P <0.001 for both), while revision rate was not statistically different between the 3 techniques. In summary, there are many more publications on PAO surgery with a wide range of reported complications. Complications after ERAO and RAO surgery are lower than PAO surgery in the literature, but it is unclear whether this represents an actual difference or a reporting bias. Lastly, there are no significant differences between revisions, or postoperative reported outcomes between the 3 techniques.

Computed Tomography–Based Three-Dimensional Analyses Show Similarities in Anterosuperior Acetabular Coverage Between Acetabular Dysplasia and Borderline Dysplasia

(1) To compare the acetabular coverage between dysplasia, borderline dysplasia, and control acetabulum in a quantitative 3-dimensional manner; and (2) to evaluate correlations between the radiologic parameters and the 3-dimensional zonal-acetabular coverage. We reviewed contralateral hip computed tomography images of patients 16 to 60 years of age who underwent 1 of 3 types of surgeries: eccentric rotational acetabular osteotomy, curved intertrochanteric varus osteotomy, and total hip replacement with minimum 1-year follow-up from January 2013 to April 2018. A point-cloud model of the acetabulum created from computed tomography was divided into 6 zones. Three-dimensional acetabular coverage was measured radially at intervals of 1°. Mean radial acetabular coverage for each zone was named ZAC (zonal acetabular coverage) and was compared among the 3 subgroups (control: 25° ≤lateral center-edge angle [LCEA] <40°; borderline: 20° ≤LCEA <25°; and dysplasia: LCEA ≤20°) statistically. Further, the correlations between the ZAC in each zone and the LCEA were analyzed using Pearson's correlation coefficient. One-hundred fifteen hips were categorized as control (36 hips), borderline (32 hips), and dysplasia (47 hips). The mean anterocranial ZAC in the borderline (87.5 ± 5.7°) was smaller than that in the control (92.6 ± 5.9°, P= .005) but did not differ compared with the dysplasia (84.5 ± 7.6°, P= .131). In contrast, the anterocaudal (71.2 ± 5.0°), posterocranial (85.0 ± 6.4°), and posterocaudal (82.4 ± 4.5°) mean ZACs in the borderline were not different from those in the control (anterocaudal, 74.3 ± 4.6°, P= .090; posterocranial, 87.9 ± 4.3°, P= .082; posterocaudal, 85.1 ± 5.0°, P=.069) respectively. Although there was a very strong positive correlation with supra-anterior ZAC and LCEA (r=0.750, P < .001), the correlation between the anterocranial ZAC and LCEA was relatively weak (r= 0.574, P < .001). The anterosuperior acetabular coverage in the borderline dysplastic acetabulum is more similar to the dysplastic acetabulum than to the normal acetabulum. This study emphasizes the importance of evaluating not only the lateral but also the anterior coverage in borderline dysplasia.

Long-Term Outcomes of Eccentric Rotational Acetabular Osteotomy Combined With Femoral Osteotomy for Hip Dysplasia

BackgroundThis study aimed at investigating the clinical outcomes of eccentric rotational acetabular osteotomy (ERAO) combined with intertrochanteric valgus osteotomy (ITVO) over a period of more than 10 years. MethodsThis is a case-control study of 39 patients (40 hips) who underwent ERAO combined with ITVO for hip dysplasia (ITVO group). Patients were matched for age, sex, follow-up period, and preoperative joint stage to 78 patients (80 hips) who underwent ERAO alone (ERAO group). We compared the clinical and radiographic outcomes and the survival rates between the groups. ResultsThe Harris Hip Score at the final follow-up was significantly lower in the ITVO group than in the ERAO group. The postoperative center edge angle, acetabular head index, and minimum joint space were significantly smaller in the ITVO group than in the ERAO group. The survival rates for the conversion to total hip arthroplasty end point were not significantly different between groups. However, survival rates for the Harris Hip Score < 80 end point were significantly poorer in the ITVO group than in the ERAO group. ConclusionThe long-term results of ERAO combined with ITVO were not satisfactory from a hip function perspective. ERAO combined with ITVO should be indicated in only young active patients with pre-osteoarthritis and initial stages of osteoarthritis.

Computer-assisted anteverting eccentric rotational acetabular osteotomy for recurrent posterior dislocation associated with acetabular retroversion: a case report

BackgroundAcetabular retroversion is a rotatory abnormality of the entire hemipelvis that includes anterior over-coverage and posterior deficiency of the acetabulum, and is associated with pincer-type femoroacetabular impingement and posterior hip instability. Acetabular retroversion is thought to cause posterior dislocation of the hip in athletes due to both the pincer-type femoroacetabular impingement and posterior hip instability.Case presentationA 26-year-old Japanese man had acetabular retroversion that induced recurrent posterior dislocation of his hip due to excessive hip flexion while wakeboarding. We performed anteverting eccentric rotational acetabular osteotomy using preoperative three-dimensional planning and an intraoperative computerized navigation system. Our patient was able to return to sports activities 1 year postoperatively.ConclusionsBoth preoperative three-dimensional surgical planning software and an intraoperative navigation system can provide a highly accurate map for this complicated surgery that simultaneously improves the pincer-type femoroacetabular impingement and posterior deficiency of the acetabulum.

A Possible New Radiographic Predictor of Progression of Osteoarthritis in Developmental Dysplasia of the Hip: The Center Gap.

Patients with comparable severities of developmental dysplasia of the hip (DDH) may variably progress to osteoarthritis (OA) over time. Although joint congruency may be associated with OA progression in patients with DDH, it has only been assessed subjectively. We assessed the gap between the rotational centers of the acetabulum and femoral head (center gap) as a possible predictive measure of OA progression in patients with DDH. In patients with bilateral DDH, we asked: (1) What is the probability of OA progression (Tönnis grade) or symptom development (pain) in the asymptomatic contralateral hip of patients with DDH undergoing unilateral joint-preserving surgery? (2) Is the center gap measurement associated with OA progression or symptom development in these hips? (3) Is the center gap measurement correlated with previous radiographic parameters? A total of 297 patients (319 hips) underwent unilateral eccentric rotational acetabular osteotomy at our institution between July 1989 and December 1999. We performed no other joint-preserving surgery to treat patients with DDH during this timeframe. The inclusion criteria for the study were patients younger than 55 years of age, the contralateral hip classified as Tönnis Grade 0, no previous surgical interventions, and asymptomatic at the time of eccentric rotational acetabular osteotomy (155 patients, 155 hips). The exclusion criteria were a contralateral hip without dysplasia (four patients, four hips), loss to followup before 10 years (42 patients, 42 hips [27%]), or missing medical records or radiographs (21 patients, 21 hips [14%]). The remaining 88 patients (88 hips; 11 males and 77 females) with a mean age of 39 years (range, 17-53 years) and mean followup of 20 years (range, 10-27 years) were analyzed. From the institutional database, radiographic parameters including the center gap in the AP view were assessed using radiographs at the time of eccentric rotational acetabular osteotomy, and the Tönnis grade was recorded 1 year postoperatively and annually thereafter retrospectively. We defined migration of the rotational center of the femoral head based on the rotational center of the acetabulum in the horizontal plane as center gap X (mm) and in the vertical plane as center gap Y (mm) and defined the absolute value between the centers as center gap distance (mm). Using κ statistics, intra- and interobserver reliabilities were determined to be 0.896 and 0.857 for center gap X, 0.912 and 0.874 for center gap Y, and 0.912 and 0.901 for the center gap distance, respectively. When patients reported any contralateral ipsilateral hip pain during clinic visits, the hip was considered symptomatic. Kaplan-Meier survivorship analyses were performed with OA progression or symptom development in the nonoperative hip as the endpoint. Multivariate analyses were performed to assess risk factors for each outcome using the Cox proportional hazards model. Correlation analyses between the center gap and other parameters including lateral center-edge angle, femoral head extrusion index, acetabular depth-to-width index, femoral head lateralization, minimum width of the joint space, head sphericity, and joint congruency were performed using Pearson's correlation coefficient. At 20 years postoperatively, the probability of OA progression in the nonoperative hip was 13% (95% confidence interval [CI], 7.1-22.1) and the probability of symptom development was 34% (95% CI, 24.7-46.1). The center gap X measurements in the groups with OA progression (lateral 2.0 ± 2.1 [SD] mm) or symptom development (lateral 0.9 ± 2.4 mm) took a more lateral direction than those in the group without OA progression (medial 0.4 ± 2.1 mm) or symptom development (medial 0.5 ± 2.0 mm) (OA progression, p < 0.001; symptom development, p = 0.005). The center gap Y measurements in the groups with OA progression (distal 2.7 ± 7.1 mm) or symptom development (distal 2.1 ± 6.0 mm) took a more distal direction than those in the group without OA progression (proximal 1.6 ± 6.2 mm) or symptom development (proximal 2.5 ± 6.1 mm) (OA progression, p = 0.027; symptom development, p = 0.001). Independent risk factors for OA progression were the femoral head extrusion index (hazard ratio [HR], 1.11; 95% CI, 1.01-1.22; p = 0.028) and the center gap X (HR, 1.52; 95% CI, 1.07-2.16; p = 0.019), whereas no independent risk factors for symptom development were found. The center gap in the horizontal plane had no correlations with any other radiographic parameter studied. The center gap in the horizontal plane had a modest association with OA progression in this group of patients with DDH. Future studies are needed to determine the normal value of the center gap for patients without DDH and to assess the center gap in lateral radiographic views. Level IV, prognostic study.

A pre-operative predictive score for the outcome of eccentric rotational acetabular osteotomy in the treatment of acetabular dysplasia and early osteoarthritis of the hip in adults.

The influence of identifiable pre-operative factors on the outcome of eccentric rotational acetabular osteotomy (ERAO) is unknown. We aimed to determine the factors that might influence the outcome, in order to develop a scoring system for predicting the prognosis for patients undergoing this procedure. We reviewed 700 consecutive ERAOs in 54 men and 646 women with symptomatic acetabular dysplasia or early onset osteoarthritis (OA) of the hip, which were undertaken between September 1989 and March 2013. The patients' pre-operative background, clinical and radiological findings were examined retrospectively. Multivariate Cox regression analysis was performed using the time from the day of surgery to a conversion to total hip arthroplasty (THA) as an endpoint. A risk score was calculated to predict the prognosis for conversion to THA, and its predictive capacity was investigated. The congruity of the hip, age, the pre-operative minimum width of the joint space and range of abduction were identified as factors predicting conversion to THA. For three groups of patients (scoring 0 to 5, 6 to 7, and 8 to 9 points), the Kaplan-Meier event-free rates of survival at 15 years post-operatively for conversion to THA were 99.6%, 85.2% and 67.3%, respectively. These four pre-operative factors are easily measured and predict the prognosis for patients following ERAO. They may be used for decision making when offering surgical treatment to patients with acetabular dysplasia and early onset osteoarthritis. Cite this article: Bone Joint J 2016;98-B:1326-32.

Preoperative prognosis score is a useful tool regarding eccentric rotational acetabular osteotomy in patients with acetabular dysplasia.

It is unknown how possible preoperative factors influence the postoperative outcome of eccentric rotational acetabular osteotomy (ERAO). We aimed to determine these factors and to develop a scoring system for predicting the prognosis after ERAO in patients with symptomatic hip dysplasia. We included 700 patients (54 men, 646 women) who underwent ERAO during September 1989 to March 2013. The patients' clinical background, preoperative clinical findings, and preoperative imaging findings were examined retrospectively. Univariate and multivariate Cox regression were performed using the time from the day of surgery to a Harris hip score (HHS) <80 as an endpoint. A failure score was defined to predict the prognosis for an HHS <80, and its predictive capacity was assessed. Ninety patients had an HHS <80. Forty-two patients underwent conversion to total hip arthroplasty (THA) after their HHS decreased to <80. Five factors were identified in relation to an HHS <80: a history of congenital dislocation of the hip, joint congruity, body mass index, the preoperative minimum joint space width, and the preoperative abduction range of motion. We estimated the weight of each factor using the results of multivariate Cox regression, and the outcome prediction scoring was obtained (0-17 points). For three groups of patients (total points of each factors: 0-5, 6-9, and ≥10 points), the Kaplan-Meier event-free survival rates at 15 years postoperatively for an HHS <80 were 97%, 81%, and 55%, respectively; the survival rates for THA conversion using this prediction scoring were 99%, 96%, and 85%, respectively. Five preoperative factors can easily and clearly predict the prognosis following ERAO. The prognosis score may be a useful tool when making a decision regarding operative treatments in adult patients with acetabular dysplasia.

Significantly Poor Outcomes of Total Hip Arthroplasty After Failed Periacetabular Osteotomy

BackgroundPeriacetabular osteotomy (PAO) is an effective treatment for preosteoarthritis and early osteoarthritis in young and active patients with hip dysplasia. However, conversion to total hip arthroplasty (THA) for failed PAO is difficult owing to morphologic changes. The objective of the present study was to investigate outcomes of patients who underwent THA for failed PAO. MethodsWe performed a case–control study. The participants were 48 patients (52 hips) who underwent THA after PAO (the osteotomy group); type of PAO was eccentric rotational acetabular osteotomy in 36 hips and rotational acetabular osteotomy in 16 hips. These patients had a mean age at surgery of 56.5 years and underwent postoperative follow-up for a mean period of 5.4 years. For the control group, after matching age, gender, and time of surgery, we included 96 patients (104 joints) who underwent primary THA for hip dysplasia. ResultsThe 2 groups demonstrated no significant difference in the preoperative Harris Hip Score. However, the osteotomy group demonstrated a significantly poor Harris Hip Score at the last follow-up, with particularly low scores for gait and activity. The osteotomy group demonstrated significantly poor range of motion at the last follow-up. Although neither group had any cases of revision surgery, both groups had 1 case of postoperative dislocation. Considering socket placement in Lewinnek’s safe zone, the osteotomy group had significantly poorer results compared to that obtained after primary THA. ConclusionThe therapeutic outcomes and socket positioning for THA after PAO were poorer compared to those of primary THA.

Surgical Education of Eccentric Rotational Acetabular Osteotomy for HIP Trainees

Periacetabular osteotomy is an excellent intervention for patients at early-stage osteoarthritis, but surgical education for this technique is more difficult than that for total hip arthroplasty. 47 joints were included from patients who underwent eccentric rotational acetabular osteotomy (ERAO) performed by 6 trainees under the instructing physician's guidance. We evaluated operative time, blood loss, radiographic parameters, clinical scores, perioperative complications, and 10-year survival rates. We also compared trainees' cases with 47 joints from patients in a sex- and age-matched control group that underwent ERAO performed by the instructing physician. Hip surgery trainees took an average of 152 minutes and the instructor took 103 minutes. Blood loss during surgery by the trainees and the instructor was 382 and 276 g, respectively. Postoperatively, for the trainee and instructor groups, respectively, the Harris Hip Score improved to 88.9 and 93.7 points; the average centre-edge angle improved to 34.0°and 36.1°; and the average acetabular head index was 93.9% and 95.7%. Perioperative and postoperative complications were observed in 14 patients of the trainee group and 3 patients of the instructor group, which were significantly different (p = 0.0061). The 10-year survival rates were 97.8% and 100% for the trainee and instructor groups, respectively. Postoperative imaging evaluations showed no evident differences in coverage. Postoperative clinical outcomes were also satisfactory. Thus, under proper guidance, education to hip surgery trainees on operative techniques is possible. Instructors need to make more effort to prevent complications by providing good education.

Surgical Techniques of Eccentric Rotational Acetabular Osteotomy.

This report describes the operative indications and essential techniques of eccentric rotational acetabular osteotomy for hip dysplasia in patients with either pre-osteoarthritis, early arthritis, or in some cases even advanced osteoarthritis of the hip. An accurate lateral decubitus position of the pelvis is important. Make a bikini skin incision and elevate the skin flap. Make a Y-shaped incision, retract the innominate fossa, and detach the greater trochanter with an oscillating saw. Partially release and divide the rectus femoris, detach the iliacus, and retract the iliopsoas. It is essential to use an osteotomy guide to perform an accurate spherical osteotomy. The osteotomy of the pubic bone is technically demanding. The acetabular fragment can be rotated to the intended position as determined by the preoperative planning. Fix the greater trochanter with two AO cancellous screws. Walking with a walker and partial weight-bearing begins one day after surgery, and full weight-bearing starts at two months postoperatively. The clinical and radiographic outcomes in the first 126 consecutive patients (132 hips) who had undergone eccentric rotational acetabular osteotomy at our institution were retrospectively assessed.IndicationsContraindicationsPitfalls & Challenges.

Biomechanical analysis and clinical efficacy of eccentric rotational acetabular osteotomy

Objective To investigate the biomechanical mechanism and report preliminary clinical efficacy of eccentric rotational acetabular osteotomy (ERAO) when conduct treatment for developmental dysplasia of the hip (DDH). Methods Biome-chanical model of the hip joint was established on six female cadaveric hips embalmed by formalin and stimulate ERAO was then performed on the model. Vertical force was loaded on the cadaveric spine from 0 N to 500 N and strain value on femoral head was measured preoperatively and postoperatively when loading force on spine reached the point of 100, 200, 300, 400 and 500 N. Stress value were then calculated base on the measurements. Besides, we reported postoperative follow-up cases which were underwent ERAO to treat DDH in our hospital from July 2007 to October 2014. A total of 25 patients (26 hips) were reported, including 6 males and 19 females. Age varies from 11 to 57 years old, and the average age was 31 years old. Postoperative hip function was evaluated by Harris hip score and anteroposterior X-ray of pelvic was taken preoperatively and postoperatively to measure the acetabular-head index (AHI), CE angle and sharp angle. Results Preoperative stress increased when loaded on spine became larger, but postoperative stress changed its increasing trend into decreasing when the load was greater than 300 N (turning point), which showed a parabolic trend. Compared with the preoperative stress under different load varying from 100 N to 500 N, postoperative stress was not statistically significant. Meanwhile, by the end of follow-up period, 18 patients (19 hips) were followed form 7 to 85 months. The average follow-up time was 40 months and the follow-up rate was 72%. Harris hip score improved from preoperative 64.3±7.2 points to 85.6±5.3 points; postoperative AHI increased an average of 36.5%, CE angle increased an average of 33.1° and sharp angle reduced an average of 12.3°. All differences between preand post-operative indexes were statistically significant. Conclusion ERAO has the ability to correct the deformity of acetabulum. It enlarges the acetabular coverage of the femoral head and thus reduces the pressure of weight-bearing area. Key words: Hip dislocation, congenital; Osteotomy; Acetabulum; Biomechanics

P.1.g.069 D-serine prevents cognitive deficits caused by acute stress

Background In periacetabular osteotomy for the treatment of developmental dysplasia of the hip, impairments in ADL due to limitations in hip flexion can occur when anterior displacement is added to lateral displacement in order to obtain sufficient femoral head coverage. This study was conducted to determine, by the range of motion (ROM) simulation based on CT images, the minimum angle of hip flexion and internal rotation at 90° of flexion that is necessary to avoid ADL impairments after eccentric rotational acetabular osteotomy (ERAO) and to estimate the angles of anterior femoral head coverage on plain radiography that enable the above flexion.Methods Of 47 hips treated with ERAO at our hospital from December 2007 to May 2012, 27 hips without progressive osteoarthritis which could be CT scanned were examined and included. The mean age at the time of surgery was 40.7 years (SD 1.8). The postoperative follow-up period was 30.2 months (SD 3.6). Two hips were in male patients and 25 hips were in female patients. The disease stage prior to surgery was pre-osteoarthritis in 5 hips, early in 11 hips, and progressive in 11 hips. We checked whether the patients were capable of activities that require deep hip flexion for the evaluation of postoperative ADL. Radiographic examination was performed before and one year after surgery to calculate LCE angle, Sharp angle, AHI, and VCA angle. The angle at which impingement of the displaced fragment of the bone and the femur appeared was measured using 3D CAD software, and the relationship between this angle and the physical findings, ADL impairment, or radiographic findings, were also examined.Results 22 out of 27 hips that were capable of 116° or more of flexion or 42° or more of internal rotation at 90° of flexion in ROM simulation showed the absence of ADL impairment and a postoperative VCA angle ≤42°, whereas 5 hips with 110° or less of flexion or 40° or less of internal rotation at 90° of flexion in ROM simulation had ADL impairments associated with limitations in hip flexion and a postoperative VCA angle ≥46°.Conclusions Anterior and lateral coverage requires a postoperative VCA angle of ≥20° to achieve anterior structural stability and an LCE angle of >25° to obtain adequate superior lateral coverage of the femoral head. A VCA angle ≤42° is required to avoid impingement during deep flexion. A VCA angle ≥46° is a probable risk factor for pincer FAI syndrome after ERAO.

Anterior coverage after eccentric rotational acetabular osteotomy for the treatment of developmental dysplasia of the hip

Background In periacetabular osteotomy for the treatment of developmental dysplasia of the hip, impairments in ADL due to limitations in hip flexion can occur when anterior displacement is added to lateral displacement in order to obtain sufficient femoral head coverage. This study was conducted to determine, by the range of motion (ROM) simulation based on CT images, the minimum angle of hip flexion and internal rotation at 90° of flexion that is necessary to avoid ADL impairments after eccentric rotational acetabular osteotomy (ERAO) and to estimate the angles of anterior femoral head coverage on plain radiography that enable the above flexion.Methods Of 47 hips treated with ERAO at our hospital from December 2007 to May 2012, 27 hips without progressive osteoarthritis which could be CT scanned were examined and included. The mean age at the time of surgery was 40.7 years (SD 1.8). The postoperative follow-up period was 30.2 months (SD 3.6). Two hips were in male patients and 25 hips were in female patients. The disease stage prior to surgery was pre-osteoarthritis in 5 hips, early in 11 hips, and progressive in 11 hips. We checked whether the patients were capable of activities that require deep hip flexion for the evaluation of postoperative ADL. Radiographic examination was performed before and one year after surgery to calculate LCE angle, Sharp angle, AHI, and VCA angle. The angle at which impingement of the displaced fragment of the bone and the femur appeared was measured using 3D CAD software, and the relationship between this angle and the physical findings, ADL impairment, or radiographic findings, were also examined.Results 22 out of 27 hips that were capable of 116° or more of flexion or 42° or more of internal rotation at 90° of flexion in ROM simulation showed the absence of ADL impairment and a postoperative VCA angle ≤42°, whereas 5 hips with 110° or less of flexion or 40° or less of internal rotation at 90° of flexion in ROM simulation had ADL impairments associated with limitations in hip flexion and a postoperative VCA angle ≥46°.Conclusions Anterior and lateral coverage requires a postoperative VCA angle of ≥20° to achieve anterior structural stability and an LCE angle of >25° to obtain adequate superior lateral coverage of the femoral head. A VCA angle ≤42° is required to avoid impingement during deep flexion. A VCA angle ≥46° is a probable risk factor for pincer FAI syndrome after ERAO.

Preoperative Planning for Eccentric Rotational Acetabular Osteotomy

Preoperative Planning for Eccentric Rotational Acetabular Osteotomy

A comparison of biomechanical changes on femoral head following rotational acetabular osteotomy and eccentric rotational acetabular osteotomy in normal cadaveric hip

Both rotational acetabular osteotomy (RAO) and eccentric rotational acetabular osteotomy (ERAO) are effective procedures for young patients with developmental dysplasia of the hip. However, no comparative study of biomechanical changes has been reported following these two procedures. We therefore explored the stress changes on femoral head after RAO and ERAO under different load conditions. Twelve female cadaveric hips without deformity were divided into RAO group and ERAO group. Stress value on femoral head was measured preoperatively and postoperatively after the vertical force was loaded on the cadaveric spine from 0 to 500 N. Stress change value was then calculated base on the measurements. In the RAO group, preoperative stress increased when loading on spine became larger, but postoperative stress changed its increasing trend into decreasing when the load was greater than 200 N (turning point). Same phenomenon was found in the ERAO group (turning point was 300 N). However, the difference between preoperative and postoperative stress was not statistically significant in both RAO and ERAO groups. Stress change value from each procedure showed similar trends. With the load growth, stress change increased firstly and then decreased, but the difference between RAO and ERAO was not statistically significant. Both RAO and ERAO could correct the abnormal biomechanical effect of dysplastic hip; moreover, they may have similar biomechanical effects on femoral head, obtaining the same clinical outcomes. Non-biomechanical factors (surgical trauma, technical complexity, etc.) also play important roles in procedure selection.

Eccentric rotational acetabular osteotomy for patients with hip osteoarthritis with sever obesity. A report of two cases

Eccentric rotational acetabular osteotomy for patients with hip osteoarthritis with sever obesity. A report of two cases

Pubic/ischial stress fractures after eccentric rotational acetabular osteotomy

BackgroundAlthough there have been several reports on the complications of periacetabular osteotomy, stress fractures occurring in the pubic and ischial bones are less well recognised. The purpose of this study was to analyse the incidence of stress fracture, factors and treatment outcomes of stress fractures in the pubic/ischial bone after eccentric rotational acetabular osteotomy (ERAO). Materials and methodsWe examined 340 hips of 290 patients (male 35 hips, female 305 hips; mean age 42 years) with whom it was possible to conduct a minimum of 1 year of follow-up observations after ERAO. The following items were investigated: presence of a pubic/ischial stress fracture after surgery; gender; age; bilateral or unilateral osteoarthritis; height, weight and body mass index; preoperative and final stages of osteoarthritis of the hip; preoperative and final center-edge (CE) angle, acetabular head index and minimum joint space; preoperative and final Japan Orthopaedic Association score; and presence of a pubic discontinuity. We then compared cases with pubic/ischial stress fracture (fractured group) with those with no fracture (nonfractured group). For the fractured group, we also investigated the onset time of the fracture. ResultsThe fractured group consisted entirely of women with a mean age of 47 years, and comprised 10 (2.9%) of the 340 patient hips examined. A statistically significant difference was observed between the two groups in pubic discontinuities (fractured group 8/10, nonfractured group 16/330; P < 0.0001) and postoperative CE angle (fractured group; 43°, nonfractured group; 36°, P = 0.0338) according to univariate analysis. However, only the pubic discontinuity rate differed significantly between the groups according to multivariate analysis (P < 0.0001). In all cases, a pubic/ischial stress fracture occurred within 3 months after surgery, and all cases had bony union. Recurrent fracture occurred in only one hip. There was no difference in the clinical outcomes of the fractured and nonfractured groups at the time of final follow-up. ConclusionsThe patients with pubic discontinuities were significantly more susceptible to a pubic/ischial stress fracture after ERAO. The presence of a pubic/ischial stress fracture did not influence the clinical outcome.

Joint space wider than 2 mm is essential for an eccentric rotational acetabular osteotomy for adult hip dysplasia

BackgroundSatisfactory intermediate-term results after an eccentric rotational acetabular osteotomy (ERAO) for the treatment of early osteoarthritis secondary to developmental dysplasia of the hip (DDH) have been reported. The purpose of this study was to investigate whether a minimum joint space width (JSW) in patients with advanced osteoarthritis secondary to DDH influences intermediate-term clinical and radiographic outcomes after performing an ERAO. MethodsA total of 113 patients (116 hips) with a JSW of ≤3 mm were consecutively treated by ERAO for advanced osteoarthritis of the hip and then were followed for more than 5 years. Based on the preoperative JSW, the patients were divided into three groups: minimum JSW of ≤1 mm (JS1 group); JSW >1 mm but ≤2 mm (JS2 group); JSW > 2 mm but ≤3 mm (JS3 group). The average ages of the JS1, JS2, and JS3 patients were 40, 44, and 43 years, respectively. The average follow-up period was 10.6 years. ResultsOverall conversion to total hip arthroplasty (THA) was performed in 14 joints. According to a Kaplan-Meier survivorship analysis at 15 years after the index operation, 96% of the patients with a JSW of >2 mm (JS3 group) did not require conversion to THA. ConclusionsA JSW of >2 mm before surgery is considered essential to obtain an excellent intermediate-term result following performance of an ERAO.