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Tanaka S, Fujii M, Kawano S, Ueno M, Nagamine S, Mawatari M. Factors associated with joint survival after transposition osteotomy of the acetabulum in patients with Tönnis grade 2 osteoarthritis secondary to hip dysplasia. Bone Joint J 2024; 106-B:783-791. [PMID: 39084631 DOI: 10.1302/0301-620x.106b8.bjj-2024-0196.r1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 08/02/2024]
Abstract
Aims The aim of this study was to determine the clinical outcomes and factors contributing to failure of transposition osteotomy of the acetabulum (TOA), a type of spherical periacetabular osteotomy, for advanced osteoarthritis secondary to hip dysplasia. Methods We reviewed patients with Tönnis grade 2 osteoarthritis secondary to hip dysplasia who underwent TOA between November 1998 and December 2019. Patient demographic details, osteotomy-related complications, and the modified Harris Hip Score (mHHS) were obtained via medical notes review. Radiological indicators of hip dysplasia were assessed using preoperative and postoperative radiographs. The cumulative probability of TOA failure (progression to Tönnis grade 3 or conversion to total hip arthroplasty) was estimated using the Kaplan-Meier product-limited method. A multivariate Cox proportional hazards model was used to identify predictors of failure. Results This study included 127 patients (137 hips). Median follow-up period was ten years (IQR 6 to 15). The median mHHS improved from 59 (IQR 52 to 70) preoperatively to 90 (IQR 73 to 96) at the latest follow-up (p < 0.001). The survival rate was 90% (95% CI 82 to 95) at ten years, decreasing to 21% (95% CI 7 to 48) at 20 years. Fair joint congruity on preoperative hip abduction radiographs and a decreased postoperative anterior wall index (AWI) were identified as independent risk factors for failure. The survival rate for the 42 hips with good preoperative joint congruity and a postoperative AWI ≥ 0.30 was 100% at ten years, and remained at 83% (95% CI 38 to 98) at 20 years. Conclusion Although the overall clinical outcomes of TOA in patients with advanced osteoarthritis are suboptimal, favourable results can be achieved in selected cases with good preoperative joint congruity and adequate postoperative anterior acetabular coverage.
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Affiliation(s)
- Shiori Tanaka
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Masanori Fujii
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Syunsuke Kawano
- Research Center for Arthroplasty, Faculty of Medicine, Saga University, Saga, Japan
| | - Masaya Ueno
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Satomi Nagamine
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Masaaki Mawatari
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
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Kazi O, Gilat R, Alvero AB, Danilkowicz R, Williams JC, Nho SJ. Staged Hip Arthroscopy with Labral Repair, Femoroplasty, and Capsular Plication Followed by Periacetabular Osteotomy for Hip Dysplasia Results in Improved Outcomes and 100% Survivorship at Minimum 2-Year Follow-Up. Arthroscopy 2024:S0749-8063(24)00411-0. [PMID: 38876446 DOI: 10.1016/j.arthro.2024.05.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 05/13/2024] [Accepted: 05/19/2024] [Indexed: 06/16/2024]
Abstract
PURPOSE To assess patient-reported outcomes (PROs), clinically significant outcomes (CSOs), and survivorship following staged hip arthroscopy with labral repair, femoroplasty, and capsular plication followed by periacetabular osteotomy (PAO) for the management of femoroacetabular impingement syndrome (FAIS) and hip dysplasia (lateral center edge angle ≤25°). METHODS A prospectively maintained database was queried to retrospectively identify patients who underwent staged primary hip arthroscopy and PAO between 1/2018-10/2021 and had a minimum 2-year follow-up. PROs collected included, Hip Outcome Score Activities of Daily Living/Sports Subscale (HOS-ADL/SS), international Hip Outcome Tool-12 item questionnaire (iHOT-12), and Visual Analog Scale for Pain (VAS Pain). CSO achievement for minimal clinical important difference (MCID) and patient acceptable symptom state (PASS) were determined through cohort specific thresholds. Rates of reoperation, including, revision hip arthroscopy and conversion to total hip arthroplasty (THA) were evaluated to determine short-term survivorship. RESULTS Thirty-nine hips met criteria for inclusion, of which 35 hips had minimum 2-year follow up (89.7% compliance). Mean age was 25±9.1 years and 91.7% of patients were female. Respective pre- and postoperative radiographic outcomes were: Alpha angle 59.8±5.9 to 39.7±2.6°, Tönnis angle 14.6±5.6° to -1.0±2.9°, lateral center-edge angle 16.6±5.5° to 36.6±4.6°, and anterior center-edge angle 15.6±9.1° to 36.1±3.8°, with statistically significant differences pre- to postoperatively for all (P<0.001). Patients demonstrated significant improvement in all PROs pre- to postoperatively (P ≤0.004). MCID and PASS achievement rates for any PRO were 93.9% and 78.8%, respectively. There were no revision hip surgeries or conversion to THA at a mean 2.7±1.0-year follow-up. Four patients (11.1%) underwent hardware removal. One patient (2.8%) experienced a postoperative infection treated with incision and drainage. CONCLUSIONS Staged hip arthroscopy and PAO for the management of hip dysplasia demonstrated improvement in PROs, high CSO achievement rates, and 100% survivorship at minimum 2-year follow-up.
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Affiliation(s)
- Omair Kazi
- Section of Young Adult Hip Surgery, Division of Sports Medicine, Department of Orthopedic Surgery, Rush Medical College of Rush University, Rush University Medical Center; Chicago, IL, USA.
| | - Ron Gilat
- Section of Young Adult Hip Surgery, Division of Sports Medicine, Department of Orthopedic Surgery, Rush Medical College of Rush University, Rush University Medical Center; Chicago, IL, USA
| | - Alexander B Alvero
- Section of Young Adult Hip Surgery, Division of Sports Medicine, Department of Orthopedic Surgery, Rush Medical College of Rush University, Rush University Medical Center; Chicago, IL, USA
| | - Richard Danilkowicz
- Section of Young Adult Hip Surgery, Division of Sports Medicine, Department of Orthopedic Surgery, Rush Medical College of Rush University, Rush University Medical Center; Chicago, IL, USA
| | - Joel C Williams
- Section of Young Adult Hip Surgery, Division of Sports Medicine, Department of Orthopedic Surgery, Rush Medical College of Rush University, Rush University Medical Center; Chicago, IL, USA
| | - Shane J Nho
- Section of Young Adult Hip Surgery, Division of Sports Medicine, Department of Orthopedic Surgery, Rush Medical College of Rush University, Rush University Medical Center; Chicago, IL, USA
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Tanaka S, Fujii M, Kawano S, Ueno M, Sonohata M, Kitajima M, Mawatari D, Mawatari M. Joint awareness following periacetabular osteotomy in patients with hip dysplasia. Bone Joint J 2023; 105-B:760-767. [PMID: 37399111 DOI: 10.1302/0301-620x.105b7.bjj-2022-1441.r1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/05/2023]
Abstract
Aims The aims of this study were to validate the Forgotten Joint Score-12 (FJS-12) in the postoperative evaluation of periacetabular osteotomy (PAO), identify factors associated with joint awareness after PAO, and determine the FJS-12 threshold for patient-acceptable symptom state (PASS). Methods Data from 686 patients (882 hips) with hip dysplasia who underwent transposition osteotomy of the acetabulum, a type of PAO, between 1998 and 2019 were reviewed. After screening the study included 442 patients (582 hips; response rate, 78%). Patients who completed a study questionnaire consisting of the visual analogue scale (VAS) for pain and satisfaction, FJS-12, and Hip disability and Osteoarthritis Outcome Score (HOOS) were included. The ceiling effects, internal consistency, convergent validity, and PASS thresholds of FJS-12 were investigated. Results The median follow-up was 12 years (interquartile range 7 to 16). The ceiling effect of FJS-12 was 7.2%, the lowest of all the measures examined. FJS-12 correlated with all HOOS subscales (ρ = 0.72 to 0.77, p < 0.001) and pain and satisfaction-VAS (ρ = -0.63 and 0.56, p < 0.001), suggesting good convergent validity. Cronbach's α was 0.95 for the FJS-12, which indicated excellent internal consistency. The median FJS-12 score for preoperative Tönnis grade 0 hips (60 points) was higher than that for grade 1 (51 points) or 2 (46 points). When PASS was defined as pain-VAS < 21 and satisfaction-VAS ≥ 77, the FJS-12 threshold that maximized the sensitivity and specificity for detecting PASS was 50 points (area under the curve (AUC) = 0.85). Conclusion Our results suggest that FJS-12 is a valid and reliable assessment tool for patients undergoing PAO, and the threshold of 50 points may be useful to determine patient satisfaction following PAO in clinical settings. Further investigation of the factors influencing postoperative joint awareness may enable improved prediction of treatment efficacy and informed decision-making regarding the indication of PAO.
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Affiliation(s)
- Shiori Tanaka
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Masanori Fujii
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Shunsuke Kawano
- Research Center for Arthroplasty, Faculty of Medicine, Saga University, Saga, Japan
| | - Masaya Ueno
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Motoki Sonohata
- Department of Orthopedic Surgery, JCHO Saga Central Hospital, Saga, Japan
| | - Masaru Kitajima
- Department of Orthopedic Surgery, Shiroishi Kyouritsu Hospital, Saga, Japan
| | - Daisuke Mawatari
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Masaaki Mawatari
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
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Fujii M, Kawano S, Ueno M, Sonohata M, Kitajima M, Tanaka S, Mawatari D, Mawatari M. Clinical results of periacetabular osteotomy with structural bone allograft for the treatment of severe hip dysplasia. Bone Joint J 2023; 105-B:743-750. [PMID: 37399069 DOI: 10.1302/0301-620x.105b7.bjj-2023-0056.r1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Aims To clarify the mid-term results of transposition osteotomy of the acetabulum (TOA), a type of spherical periacetabular osteotomy, combined with structural allograft bone grafting for severe hip dysplasia. Methods We reviewed patients with severe hip dysplasia, defined as Severin IVb or V (lateral centre-edge angle (LCEA) < 0°), who underwent TOA with a structural bone allograft between 1998 and 2019. A medical chart review was conducted to extract demographic data, complications related to the osteotomy, and modified Harris Hip Score (mHHS). Radiological parameters of hip dysplasia were measured on pre- and postoperative radiographs. The cumulative probability of TOA failure (progression to Tönnis grade 3 or conversion to total hip arthroplasty) was estimated using the Kaplan-Meier product-limited method, and a multivariate Cox proportional hazard model was used to identify predictors for failure. Results A total of 64 patients (76 hips) were included in this study. The median follow-up period was ten years (interquartile range (IQR) five to 14). The median mHHS improved from 67 (IQR 56 to 80) preoperatively to 96 (IQR 85 to 97) at the latest follow-up (p < 0.001). The radiological parameters improved postoperatively (p < 0.001), with the resulting parameters falling within the normal range in 42% to 95% of hips. The survival rate was 95% at ten years and 80% at 15 years. Preoperative Tönnis grade 2 was an independent risk factor for TOA failure. Conclusion Our findings suggest that TOA with structural bone allografting is a viable surgical option for correcting severely dysplastic acetabulum in adolescents and young adults without advanced osteoarthritis, with favourable mid-term outcomes.
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Affiliation(s)
- Masanori Fujii
- Department of Orthopedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Shunsuke Kawano
- Research Center for Arthroplasty, Faculty of Medicine, Saga University, Saga, Japan
| | - Masaya Ueno
- Department of Orthopedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Motoki Sonohata
- Department of Orthopaedic Surgery, JCHO Saga Central Hospital, Saga, Japan
| | - Masaru Kitajima
- Department of Orthopedic Surgery, Shiroishi Kyoritsu Hospital, Saga, Japan
| | - Shiori Tanaka
- Department of Orthopedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Daisuke Mawatari
- Department of Orthopedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Masaaki Mawatari
- Department of Orthopedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
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Andronic O, Germann C, Jud L, Zingg PO. Factors influencing patient-reported outcomes following periacetabular osteotomy and open osteochondroplasty in the setting of borderline hip dysplasia. Bone Joint J 2023; 105-B:735-742. [PMID: 37391200 DOI: 10.1302/0301-620x.105b7.bjj-2022-1058.r2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/02/2023]
Abstract
Aims This study reports mid-term outcomes after periacetabular osteotomy (PAO) exclusively in a borderline hip dysplasia (BHD) population to provide a contrast to published outcomes for arthroscopic surgery of the hip in BHD. Methods We identified 42 hips in 40 patients treated between January 2009 and January 2016 with BHD defined as a lateral centre-edge angle (LCEA) of ≥ 18° but < 25°. A minimum five-year follow-up was available. Patient-reported outcomes (PROMs) including Tegner score, subjective hip value (SHV), modified Harris Hip Score (mHHS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were assessed. The following morphological parameters were evaluated: LCEA, acetabular index (AI), α angle, Tönnis staging, acetabular retroversion, femoral version, femoroepiphyseal acetabular roof index (FEAR), iliocapsularis to rectus femoris ratio (IC/RF), and labral and ligamentum teres (LT) pathology. Results The mean follow-up was 96 months (67 to 139). The SHV, mHHS, WOMAC, and Tegner scores significantly improved (p < 0.001) at last follow-up. According to SHV and mHHS, there were three hips (7%) with poor results (SHV < 70), three (7%) with a fair score (70 to 79), eight (19%) with good results (80 to 89), and 28 (67%) who scored excellent (> 90) at the last follow-up. There were 11 subsequent operations: nine implant removals due to local irritation, one resection of postoperative heterotopic ossification, and one hip arthroscopy for intra-articular adhesions. No hips were converted to total hip arthroplasty at last follow-up. The presence of preoperative labral lesions or LT lesions did not influence any PROMs at last follow-up. From the three hips that had poor PROMs, two have developed severe osteoarthritis (> Tönnis II), presumably due to surgical overcorrection (postoperative AI < -10°). Conclusion PAO is reliable in treating BHD with favourable mid-term outcomes. Concomitant LT and labral lesions did not negatively influence outcomes in our cohort. Technical accuracy with avoidance of overcorrection is essential in achieving successful outcomes.
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Affiliation(s)
- Octavian Andronic
- Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Christoph Germann
- Department of Radiology, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Lukas Jud
- Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
| | - Patrick O Zingg
- Department of Orthopaedics, Balgrist University Hospital, University of Zürich, Zürich, Switzerland
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Kitamura K, Fujii M, Ikemura S, Hamai S, Motomura G, Nakashima Y. Factors Associated With Abnormal Joint Contact Pressure After Periacetabular Osteotomy: A Finite-Element Analysis. J Arthroplasty 2022; 37:2097-2105.e1. [PMID: 35526756 DOI: 10.1016/j.arth.2022.04.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 04/16/2022] [Accepted: 04/29/2022] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Identifying factors associated with poor hip contact mechanics after periacetabular osteotomy (PAO) may help surgeons optimize acetabular corrections in individual patients. We performed individual-specific finite-element analyses to identify preoperative morphological and surgical correction factors for abnormal contact pressure (CP) after PAO. METHODS We performed finite-element analyses before and after PAO with reference to the standing pelvic position on individual-specific 3-dimensional hip models created from computed tomography images of 51 dysplastic hips. Nonlinear contact analyses were performed to calculate the joint CP of the acetabular cartilage during a single-leg stance. RESULTS The maximum CP decreased in 50 hips (98.0%) after PAO compared to preoperative values, and the resulting maximum CP was within the normal range (<4.1 MPa) in 33 hips (64.7%). Multivariate analysis identified the roundness index of the femoral head (P = .002), postoperative anterior center-edge angle (CEA; P = .004), and surgical correction of lateral CEA (Δlateral CEA; P = .003) as independent predictors for abnormal CP after PAO. A preoperative roundness index >54.3°, a postoperative anterior CEA <36.3°, and a Δlateral CEA >27.0° in the standing pelvic position predicted abnormal CP after PAO. CONCLUSION PAO normalized joint CP in 64.7% of the patients but was less likely to normalize joint CP in patients with aspheric femoral heads. Successful surgical treatment depends on obtaining adequate anterior coverage and avoiding excessive lateral correction, while considering the physiological pelvic tilt in a weight-bearing position.
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Affiliation(s)
- Kenji Kitamura
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Masanori Fujii
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Satoshi Ikemura
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Satoshi Hamai
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Goro Motomura
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yasuharu Nakashima
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Risk Factors for Composite Failure of Hip Dysplasia Treated With Periacetabular Osteotomy: A Minimum 10-Year Follow-up. J Am Acad Orthop Surg 2022; 30:e690-e702. [PMID: 35171882 DOI: 10.5435/jaaos-d-21-00535] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 01/05/2022] [Indexed: 02/01/2023] Open
Abstract
INTRODUCTION Periacetabular osteotomy (PAO) is a common surgical treatment of prearthritic hip dysplasia in young adults, but there are few long-term studies of clinical outcomes. The purpose of this investigation was to report a minimum 10-year clinical follow-up of hip dysplasia treated with PAO and identify risk factors for composite failure. METHODS We identified 151 patients (198 hips) who underwent PAO to treat hip dysplasia at a single institution. Enrolled subjects completed a series of six patient-reported outcome instruments and provided information about subsequent surgeries. We defined composite failure as conversion to total hip arthroplasty or modified Harris Hip Score ≤70. Logistic regression with generalized estimating equations was used to evaluate the relationships between odds of failure and potential predictor variables in univariate and multivariate analyses. RESULTS A total of 124 subjects (167 hips) with a minimum 10-year follow-up were enrolled. The median time from PAO to the final follow-up was 13 years (range 10-18 years). There were 71 hips that met criteria for failure: 32 with total hip arthroplasty and 39 with modified Harris Hip Score ≤70. Univariate logistic regression analyses revealed multiple preoperative factors that predicted composite failure: increased age and body mass index, osteoarthritis (OA), and more severe acetabular dysplasia. Postoperative factors that predicted failure included lateral undercoverage and formation of heterotopic ossification (HO). The final multivariate model identified body mass index ≥30 kg/m2 (odds ratio [OR], 3.84 [95% confidence interval (CI), 1.68-8.78], P = 0.001), higher preoperative Tönnis grade OA (OR, 2.65 [95% CI, 1.50-4.66], P < 0.001), and HO formation (OR, 16.52 [95% CI, 2.08-135.96], P = 0.009) as independent predictors of failure. CONCLUSIONS This study corroborates current hip dysplasia literature, identifying increasing age and presence of preoperative OA as risk factors for composite failure in univariate analyses. In addition, we found that obesity and HO formation were independent predictors of persistent hip dysfunction. LEVEL OF EVIDENCE Therapeutic Level IV.
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Kitamura K, Fujii M, Iwamoto M, Ikemura S, Hamai S, Motomura G, Nakashima Y. Is Anterior Rotation of the Acetabulum Necessary to Normalize Joint Contact Pressure in Periacetabular Osteotomy? A Finite-element Analysis Study. Clin Orthop Relat Res 2022; 480:67-78. [PMID: 34228657 PMCID: PMC8673984 DOI: 10.1097/corr.0000000000001893] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 06/11/2021] [Indexed: 01/31/2023]
Abstract
BACKGROUND Inappropriate sagittal plane correction can result in an increased risk of osteoarthritis progression after periacetabular osteotomy (PAO). Individual and postural variations in sagittal pelvic tilt, along with acetabular deformity, affect joint contact mechanics in dysplastic hips and may impact the direction and degree of acetabular correction. Finite-element analyses that account for physiologic pelvic tilt may provide valuable insight into the effect of PAO on the contact mechanics of dysplastic hips, which may lead to improved acetabular correction during PAO. QUESTIONS/PURPOSES We performed virtual PAO using finite-element models with reference to the standing pelvic position to clarify (1) whether lateral rotation of the acetabulum normalizes the joint contact pressure, (2) risk factors for abnormal contact pressure after lateral rotation of the acetabulum, and (3) whether additional anterior rotation of the acetabulum further reduces contact pressure. METHODS Between 2016 and 2020, 85 patients (92 hips) underwent PAO to treat hip dysplasia. Eighty-two patients with hip dysplasia (lateral center-edge angle < 20°) were included. Patients with advanced osteoarthritis, femoral head deformity, prior hip or spine surgery, or poor-quality images were excluded. Thirty-eight patients (38 hips) were eligible to participate in this study. All patients were women, with a mean age of 39 ± 10 years. Thirty-three women volunteers without a history of hip disease were reviewed as control participants. Individuals with a lateral center-edge angle < 25° or poor-quality images were excluded. Sixteen individuals (16 hips) with a mean age of 36 ± 7 years were eligible as controls. Using CT images, we developed patient-specific three-dimensional surface hip models with the standing pelvic position as a reference. The loading scenario was based on single-leg stance. Four patterns of virtual PAO were performed in the models. First, the acetabular fragment was rotated laterally in the coronal plane so that the lateral center-edge angle was 30°; then, anterior rotation in the sagittal plane was added by 0°, 5°, 10°, and 15°. We developed finite-element models for each acetabular position and performed a nonlinear contact analysis to calculate the joint contact pressure of the acetabular cartilage. The normal range of the maximum joint contact pressure was calculated to be < 4.1 MPa using a receiver operating characteristic curve. A paired t-test or Wilcoxon signed rank test with Bonferroni correction was used to compare joint contact pressures among acetabular positions. We evaluated the association of joint contact pressure with the patient-specific sagittal pelvic tilt and acetabular version and coverage using Pearson or Spearman correlation coefficients. An exploratory univariate logistic regression analysis was performed to identify which of the preoperative factors (CT measurement parameters and sagittal pelvic tilt) were associated with abnormal contact pressure after lateral rotation of the acetabulum. Variables with p values < 0.05 (anterior center-edge angle and sagittal pelvic tilt) were included in a multivariable model to identify the independent influence of each factor. RESULTS Lateral rotation of the acetabulum decreased the median maximum contact pressure compared with that before virtual PAO (3.7 MPa [range 2.2-6.7] versus 7.2 MPa [range 4.1-14 MPa], difference of medians 3.5 MPa; p < 0.001). The resulting maximum contact pressures were within the normal range (< 4.1 MPa) in 63% of the hips (24 of 38 hips). The maximum contact pressure after lateral acetabular rotation was negatively correlated with the standing pelvic tilt (anterior pelvic plane angle) (ρ = -0.52; p < 0.001) and anterior center-edge angle (ρ = -0.47; p = 0.003). After controlling for confounding variables such as the lateral center-edge angle and sagittal pelvic tilt, we found that a decreased preoperative anterior center-edge angle (per 1°; odds ratio 1.14 [95% CI 1.01-1.28]; p = 0.01) was independently associated with elevated contact pressure (≥ 4.1 MPa) after lateral rotation; a preoperative anterior center-edge angle < 32° in the standing pelvic position was associated with elevated contact pressure (sensitivity 57%, specificity 96%, area under the curve 0.77). Additional anterior rotation further decreased the joint contact pressure; the maximum contact pressures were within the normal range in 74% (28 of 38 hips), 76% (29 of 38 hips), and 84% (32 of 38 hips) of the hips when the acetabulum was rotated anteriorly by 5°, 10°, and 15°, respectively. CONCLUSION Via virtual PAO, normal joint contact pressure was achieved in 63% of patients by normalizing the lateral acetabular coverage. However, lateral acetabular rotation was insufficient to normalize the joint contact pressure in patients with more posteriorly tilted pelvises and anterior acetabular deficiency. In patients with a preoperative anterior center-edge angle < 32° in the standing pelvic position, additional anterior rotation is expected to be a useful guide to normalize the joint contact pressure. CLINICAL RELEVANCE This virtual PAO study suggests that biomechanics-based planning for PAO should incorporate not only the morphology of the hip but also the physiologic pelvic tilt in the weightbearing position in order to customize acetabular reorientation for each patient.
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Affiliation(s)
- Kenji Kitamura
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Masanori Fujii
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Miho Iwamoto
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Satoshi Ikemura
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Satoshi Hamai
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Goro Motomura
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yasuharu Nakashima
- Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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