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Periacetabular osteotomy

94 citationsUpdated Sep 2026

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Overview

Periacetabular osteotomy is an effective technique for treating symptomatic developmental dysplasia of the hip and acetabular retroversion in selected young patients with closed triradiate cartilage [16, 20, 3]. The procedure provides pain relief and improved hip function in most patients over short- to midterm followup [1]. Refinements in the periacetabular osteotomy technique and perioperative management have markedly improved clinical outcomes and recovery [2]. Optimal combined anteversion should be considered during the procedure [4]. While the Bernese periacetabular osteotomy yields favourable mid-to long-term outcomes conditional on stringent patient selection criteria [10], it is effective for painful hip dysplasia with complications expected in as many as 15% of cases [17]. For surgeons experienced with the procedure, it is safe but associated with a 5.9% risk of grade-III or IV complications beyond the learning curve [11].

The procedure is indicated for specific patient subgroups who do not do well with hip arthroscopy alone [27]. Combined periacetabular osteotomy and femoral head-neck junction osteochondroplasty provides effective correction of associated femoral head-neck deformities and produces similar early functional outcomes compared with isolated periacetabular osteotomy [8]. Single-stage combined hip arthroscopy with periacetabular osteotomy results in improvement in patient-reported outcomes and arthroplasty free survivorship of 92% at median 2.5 year follow-up [26]. When performed by an experienced surgeon, the addition of arthroscopy before periacetabular osteotomy can be done safely and does not increase the complication rate [13]. The combination of hip arthroscopy and periacetabular osteotomy is safe and effective, though clearer definitions for labral pathology and indications for repair or debridement are required [29]. Sufficient acetabular reorientation with concomitant arthroscopic debridement showed successful long-term outcomes for acetabular dysplasia in adults [18].

Periacetabular osteotomy provided excellent quality of life outcomes in a high percentage of patients older than 40 years, though it should only be performed in highly selected cases [5]. The HOOS appears to be the most appropriate measure of patient-reported outcome in patients undergoing periacetabular osteotomy [7]. The preoperative presence of acetabular cysts did not influence the results of periacetabular osteotomy [15]. Periacetabular osteotomy used as a salvage procedure for patients with hip instability recalcitrant to prior arthroscopy demonstrated substantial improvement in patient-reported outcome measures and radiographic correction of acetabular coverage [6]. Patients with a history of periacetabular osteotomy were more likely to deliver future children by cesarean section, which could be attributable to obstetrician preference [12]. Total hip arthroplasty is a reasonable surgical intervention for symptomatic dysplasia patients who have mild arthritis and do not qualify for periacetabular osteotomy [24]. Elevation of hip joint centers as much as 10 mm is one therapeutic option in the case of severe acetabular defects following total hip arthroplasty after periacetabular osteotomy [9].

Anatomy & Pathophysiology

Hip Dysplasia and Joint Mechanics

In patients with hip dysplasia, abnormal loading reduces the weightbearing area, resulting in higher contact stresses and subsequent cartilage breakdown [101]. Patient age and hip shape are critical determinants of the resulting hip mechanics [61]. Long-term exposure to elevated cartilage contact stresses may alter joint morphology, rendering hips less amenable to joint-preservation procedures such as periacetabular osteotomy [84]. Individual and postural variations in physiologic pelvic tilt influence joint contact pressure [72], while hips with lower anteversion or a larger difference between anatomic and functional anteversion are more likely to be symptomatic [75]. Concomitant lumbopelvic deformity affecting hip joint morphology can aggravate clinical symptoms, leading to earlier presentation in patients undergoing periacetabular osteotomy [102].

Muscle-induced biomechanics exert wide-reaching effects on intra-articular loads and patient perceptions of health and function [57]. In patients with developmental dysplasia of the hip, muscle-induced biomechanical variables are associated with worse function and pain outcomes, suggesting these variables predict prognosis better than bony anatomy alone [94].

Cartilage Damage Patterns

Hip morphology dictates the pattern of articular cartilage injury [149]. In femoroacetabular impingement, repeated compression forces cause cartilage injuries in the anterosuperior acetabulum and anterolateral femoral head [149]. Conversely, acetabular dysplasia causes instability and anterolateral migration of the femoral head, leading to chronic shear stress at the acetabular margin; this results in labro-chondral dissociation and extensive full-thickness chondral defects [149]. In patients with borderline dysplasia, cartilage damage frequently occurs in the pericotyloid fossa area of the acetabulum and the apex of the femoral head [149].

Instability and Soft Tissue Factors

Hip dysplasia is a pathoanatomic osseous morphology associated with hip instability, which may be partly attributable to hip capsular thickness [77]. Acetabular retroversion and decreased posterior coverage are associated with sports-related posterior hip dislocation in adolescents [51]. Periacetabular osteotomy improves hip microinstability between supine and standing radiographs in symptomatic hip dysplasia [74]. Consequently, weightbearing postural radiographs are crucial for understanding hip biomechanics and refining surgical corrections during periacetabular osteotomy [74].

Biomechanical Effects of Osteotomy

Periacetabular osteotomy is one of the most effective surgical procedures for reorienting the acetabulum in patients with symptomatic dysplasia and deficiency of femoral head coverage [21]. From a biomechanical perspective, rotational acetabular osteotomy is more effective in relieving hip joint stress compared with shelf procedure and Chiari osteotomy [81]. The procedure causes reductions in hip abduction and internal rotation but greater increases in hip adduction and external rotation [88].

The degree of acetabular correction in the coronal plane required to minimize joint contact pressure varies among patients [99]. Different combinations of acetabular rotations result in large variations in femoral head coverage and hip motion, meaning no single combination is applicable to all cases [90]. Higher degrees of fragment reorientation in abduction and extension may limit the ability to achieve intended improvements in overall hip biomechanics, a finding especially pronounced in reverse periacetabular osteotomy for acetabular retroversion or protrusio acetabuli [80]. Reorientation of the acetabulum reduces stress at the acetabular rim, shifts the os acetabuli out of the stress region, and allows union of the bony fragment with the acetabulum [93]. A higher hip center gains more bone coverage but decreases the range of hip flexion and internal rotation [100].

Pathomechanics and Natural History

The three primary factors involved in preservation of the hip joint include femoroacetabular impingement, hip dysplasia/instability, and femoral torsion abnormalities [104, 148]. An imbalance in any of these factors may result in damage to the acetabular labrum and femoroacetabular cartilage, leading to early hip osteoarthritis [148]. Additional studies are needed to determine protective or adaptive factors in patients with abnormal anatomy who do not develop early osteoarthritis and to determine whether joint-preserving hip surgery extends the life of the native hip joint [76].

High-level sport and combat sports are major risk factors for mechanical hip pathology in young adults, and a familial history of hip pathology is confirmed [86]. The clinical results of osteotomy are variable, with remarkably durable restoration of the joint in some cases, but overall results fail to approach those of total hip reconstruction [126]. The reasons for both the successes and the failures of osteotomy are related in part to a lack of understanding of the pathomechanics of osteoarthritis and imperfect knowledge of the mechanical effects of osteotomy on tissue remodeling and regeneration [126].

Classification

Directional Instability Framework: A diagnostic framework categorizes symptomatic dysplastic hips into three groups based on the primary direction of instability: anterior, posterior, and global [127].

Morphologic Subtypes: Three distinct morphologic subtypes of acetabular deficiency are common in young adult patients with acetabular dysplasia [36]. Recognizing these subtypes is essential for diagnostic and surgical treatment considerations to optimize acetabular correction and avoid femoroacetabular impingement [36].

Other Considerations: The radiographic classification of "borderline dysplastic" (LCEA 20° and <25°) and "dysplastic" (LCEA <20°) is unreliable with respect to stability [30]. Computed tomography-based three-dimensional analyses show similarities in anterosuperior acetabular coverage between acetabular dysplasia and borderline dysplasia [133]. The Femoro-Epiphyseal Acetabular Roof (FEAR) index is a measurement associated with instability in borderline hip dysplasia [30].

In acetabular dysplasia, deficiency of the anterosuperior acetabular rim is commonly present and may result in the anterior inferior iliac spine (AIIS) being positioned closer to the acetabular rim [132]. Prominent AIIS morphologies are common in patients with acetabular dysplasia undergoing periacetabular osteotomy [132].

Clinical Presentation

Demographics and Onset

Symptomatic acetabular dysplasia in skeletally mature patients presents with a strong female predominance, affecting 72% of cases compared to 28% in males [98]. The mean age at presentation is 24 years [98]. The onset of symptoms is typically insidious, occurring in 97% of affected hips [98].

Symptoms

Pain is the primary complaint, with moderate-to-severe daily pain reported in 77% of symptomatic hips [98]. Localization is most frequent in the groin (72%) and the lateral aspect of the hip (66%) [98]. Activity-related hip pain is present in 88% of cases, and activity restriction frequently diminishes pain in 75% of patients [98].

Physical Examination

Clinical examination reveals a limp in 48% of hips with symptomatic acetabular dysplasia [98]. A positive Trendelenburg sign is present in 38% of cases [98]. Notably, a positive impingement sign is observed in 97% of hips [98].

Radiographic and Diagnostic Considerations

Radiographic classification based on lateral center-edge angle (LCEA) is unreliable with respect to stability; specifically, the distinction between 'borderline dysplastic' (LCEA 20° and <25°) and 'dysplastic' (LCEA <20°) does not reliably predict stability [30]. Acetabular and femoral osseous abnormalities are commonly associated with labral tears, and recognizing these abnormalities is important to optimize surgical treatment for patients with symptomatic labral disease [123]. In Japanese patients with hip pain, radiological evidence of symptomatic femoroacetabular impingement is not uncommon, with cam deformity findings being the most common presentation [48]. For patients with combined borderline hip dysplasia and excessive femoral anteversion, clinicians should evaluate for the Beighton score and additional radiographic factors suggestive of instability [121]. Findings of the Beighton score and additional radiographic factors suggestive of instability may portend inferior outcomes after arthroscopic treatment in isolation [121].

Patient-Reported Outcomes

Patients with borderline hip dysplasia demonstrate worse preoperative patient-reported outcome measures than those with frank dysplasia [120].

Investigations

Plain radiography: Conventional radiographs are the first-line imaging studies for hip pain, determining the presence of fractures, degenerative changes, and abnormal joint morphology [62]. A complete hip series includes an anterior-posterior (AP) pelvis, a centered AP hip, a lateral view (frog-leg, cross-table, Dunn 45° or 90°), and a false-profile (Lequesne) view [63]. Standard AP radiographs examine bony architecture, joint space narrowing, bone quality, and femoral head coverage [62]. Acetabular morphology is assessed on AP pelvis radiographs for overcoverage and undercoverage [63]. The "crossover" sign indicates acetabular retroversion related to lateralization of the anterior acetabular wall relative to the posterior acetabular wall [63]. An optimal AP pelvis image is required for this sign, as pelvic tilt or rotation may lead to false-positive and false-negative results [63]. For neutral pelvic tilt, the sacrococcygeal joint should be between 3 and 5 cm above the superior border of the symphysis pubis [63]. The ilioischial line and acetabular fossa contour are assessed on AP pelvis radiographs, with coxa profunda diagnosed when the fossa line touches or is medial to the ilioischial line [63].

The femoral head-neck junction morphology is often assessed using the alpha angle [63]. The Dunn view and frog leg view are appropriate for measuring the alpha angle to determine impingement [62]. Some studies indicate that radiographs, particularly the Dunn 45° view, may be more accurate for alpha angle measurement than CT or MRI [63]. The femoral head extrusion index is defined by the length of the femoral head beyond the acetabulum as a percentage of the total horizontal width of the femoral head, with values greater than 25% considered abnormal [63]. The Tönnis angle is defined by the angle of the acetabular sourcil and a line parallel to the transverse pelvis axis, with angles between 0° and 10° considered normal [63]. The lateral center-edge angle of Wiberg is the angle between a line from the center of the femoral head perpendicular to the transverse pelvis axis and a second line from the center of the femoral head to the superolateral most point of the acetabulum [63]. Center-edge angles of 20°–40° are considered normal, while angles from 20° to 25° are considered borderline [63].

Osteoarthritis of the hip can be categorized using the Kellgren-Lawrence or Tönnis classifications [63]. The Kellgren-Lawrence classification is a 4-point grading system classified into doubtful, mild, moderate, and severe [63]. The Tönnis classification is a 3-point grading system categorized into mild, moderate, and severe [63]. Radiographic and clinical severity do not necessarily correlate, particularly if the radiographs are non-weight-bearing or if false-profile views are not included [63]. The windshield wiper sign is a radiographic instability sign visible on plain radiographs that predicts hip instability and allows for the planning of combined arthroscopic cartilage therapy and periacetabular osteotomy [125]. Radiographic reference values for acetabular under- and overcoverage may be used for radiographic evaluation of symptomatic hips, may offer possible predictors for surgical outcomes, and serve to guide clinical decision-making [143].

CT: CT scans are effective for examining cortical and cancellous bone and can be used to create three-dimensional reconstructions of the hip for use in surgical planning [62]. Measurements of femoral head coverage and acetabular and femoral impingement can be performed reliably using CT images [62]. CT overcomes the limitations of radiography by providing three-dimensional assessment of bony morphology and, to some degree, assessment of soft-tissue abnormalities [56]. Combined with arthrography, CT can evaluate chondrolabral abnormalities, specifically in patients with contraindications to MRI [56]. Low-dose CT with three-dimensional reformats is particularly useful in surgical planning of complex or borderline deformities [68].

MRI: For patients suspected of soft tissue or intra-articular pathology, MRI is the modality of choice, given its superior sensitivity and specificity [62]. The soft-tissue contrast of MRI is superior to other imaging modalities in assessing both intra-articular and extra-articular hip pathology [56]. Conventional MRI is effective at identifying osteochondral injuries, musculotendinous pathologies, and inflammation [62]. Magnetic resonance arthrography (MRA) is more appropriate to determine injuries to the labrochondral structures and the ligamentum teres and identify the presence of loose bodies and synovial chondromatosis [62]. MRA can further increase conspicuity of intra-articular lesions and is useful following hip preservation surgeries [56]. MRI provides information regarding the integrity of the acetabular labrum and articular cartilage, as well as the anatomy of the proximal femur and the version of the acetabulum and femur [68].

In the accurate detection and staging of articular cartilage lesions, the utility of MRA is reduced, with sensitivity reported to be less than 50% compared with arthroscopic findings [62]. The sensitivity of MRI to acetabular rim chondral lesions is limited [68]. Recent advances in MRI imaging techniques, such as delayed gadolinium-enhanced MR imaging and T2 mapping, allow for a more in-depth analysis of the structure of articular cartilage [62]. Delayed gadolinium-enhanced MR imaging and T2 mapping were effective at detecting early changes to the articular cartilage surfaces of patients with hip dysplasia and femoroacetabular impingement [62]. Noncontrast MRI at 3T is generally adequate for diagnosing intra-articular pathology [66]. If 3T imaging is unavailable, MRA can be considered at 1.5T for increased diagnostic accuracy [66]. A prospective study found similar accuracies between noncontrast 3T MRI and 1.5T MRA in femoroacetabular impingement [64]. In a retrospective study evaluating the accuracy of noncontrast 3T MRI versus hip arthroscopy, accuracy for labral tears and acetabular cartilage lesions was 98% and 90%, respectively [64]. Preoperative MRI evaluation of femoral anteversion is recommended as essential rather than adjunctive [142]. Coronal femoroacetabular distance and limbus thickness on post-reduction MRI help predict hips that will have residual acetabular dysplasia in the long term after closed or open reduction [141].

Ultrasonography: Ultrasonography provides real-time dynamic assessment of the hip and is useful in diagnosing soft-tissue abnormalities about the hip joint [56]. It is particularly useful in providing real-time guidance during diagnostic and therapeutic procedures [56]. Ultrasonography can be an effective modality to identify musculotendinous disruptions, effusions associated with intra-articular pathology, or inflammatory conditions, such as bursitis [62]. It is being increasingly used for targeted injections into muscles, tendons, or intra-articularly around the hip [62]. Ultrasonography shows nonossified structures such as the femoral head and is useful to diagnose hip dysplasia and dislocation [67]. It provides dynamic assessment of structures such as tendon and nerve subluxation [67]. Although ultrasonography is a valuable tool to examine pediatric hip conditions, its utility in evaluating the adult hip is limited [62]. Ultrasonography cannot image inside bone because bone cortex reflects almost all sound waves [67]. Internal joint structures are not well visualized by ultrasonography unless they are in a superficial location [67].

Other Considerations: A thorough understanding of normal anatomy and biomechanics is necessary to identify pathology and determine the appropriate course of treatment [55]. Because many hip conditions present with similar symptoms, a comprehensive clinical examination is required to determine a differential diagnosis [55]. A thorough history is essential to differentiating between common causes of hip pain [55]. Findings from imaging studies should complement clinical examination findings to provide the most accurate diagnosis [55]. Clinical examination tests and imaging findings should be used to confirm a suspected clinical diagnosis [55]. Thorough preoperative evaluation of radiographs and advanced imaging is encouraged for all patients being considered for hip arthroscopy [49].

Patients with symptomatic femoroacetabular impingement frequently present with activity-related groin pain that is exacerbated by hip flexion activities [68]. Patients with femoroacetabular impingement will exhibit restricted hip internal rotation in 90° of flexion [68]. The impingement test (flexion, adduction, internal rotation) will elicit pain in patients with femoroacetabular impingement, but the test is not specific for the condition [68]. Surgeons should not ignore posterior hip or gluteal pain or discomfort after periacetabular osteotomy as it could originate from ischiofemoral impingement [32]. A proper investigation and clinical assessment can help define the source of pain in cases of suspected ischiofemoral impingement after periacetabular osteotomy [32].

Treatment

Non-Operative

The provided evidence does not detail specific conservative management protocols such as weight loss, physical therapy, or pharmacologic interventions. However, patients with prior nonoperative or operative treatment for dysplasia of the hip are likely to have good pain relief and function after periacetabular osteotomy [22].

Operative

Indications: The Bernese periacetabular osteotomy is effective for treating painful hip dysplasia [17] and is currently favored for restoring pelvic anatomy with good correction and minimal secondary deformity [40]. It remains a viable option for patients older than 40 years, provided they are highly selected, as it still provides excellent quality of life outcomes in a high percentage of this demographic [5]. For patients with borderline hip dysplasia, the procedure improves activity levels and hip function [25], and instability-driven symptoms primarily indicate its use [122]. Acetabular rim trimming and periacetabular osteotomy are the best described surgical options for acetabular retroversion [3]. Total hip arthroplasty is a reasonable intervention for symptomatic dysplasia patients with mild arthritis who do not qualify for periacetabular osteotomy [24]. Patients with prior nonoperative or operative treatment for dysplasia can be counseled on the potential for increased complications and incomplete correction [22].

Surgical Approach / Technique: Isolated lateral rotation of the acetabular fragment should be the predominant direction of correction [14]. The anterior approach utilizes an oblique inguinal incision, a technique that respects tension lines to allow healing without dehiscence or hypertrophic changes [85]. A curved periacetabular osteotomy modification aims to reduce postoperative complications and promote early rehabilitation through minimally invasive exposure and spherical osteotomy of the acetabulum [43]. This modification avoids extensive dissection of the abductors from the outer aspect of the pelvis, which may cause ischemic insult to the gluteus medius muscle [43]. Conversely, a CORR Insights commentary argues that preservation of the intact posterior column in the Bernese technique serves no useful purpose beyond vanity and may be responsible for persistent technical difficulties [50]. Modifying the posterior column cut plane or using alternative techniques like the Birmingham Interlocking Pelvic Osteotomy may improve outcomes [50].

Combined Procedures: Periacetabular osteotomy can be combined with femoral head-neck junction osteochondroplasty to effectively correct associated femoral head-neck deformities [8]. This combined procedure produces similar early functional outcomes compared with isolated periacetabular osteotomy [8]. Additionally, arthroscopy serves as a powerful tool to treat intra-articular hip pathology secondary to dysplasia while periacetabular osteotomy improves bony coverage and alignment [28]. Through a specialized team approach, all relevant pathology can be addressed to achieve successful outcomes in combined hip arthroscopy and periacetabular osteotomy [28].

Complications and Risks: Complications may be expected in as many as 15% of cases following Bernese periacetabular osteotomy [17]. The risk from chemoprophylaxis and the development of hematoma may be greater than the risk of clinically important venous thromboembolism in patients undergoing the procedure [42]. Patients with a history of periacetabular osteotomy were more likely to deliver future children by cesarean section [12].

Long-term Outcomes and Revision: One-third of hips survive 30 years after periacetabular osteotomy with good clinical results, no progression of arthritis, or conversion to total hip arthroplasty [20]. Activity levels and hip function improve postoperatively in patients with borderline hip dysplasia [25], and participation in high-impact sports is maintained [25]. The HOOS appears to be the most appropriate measure of patient-reported outcome in this population [7]. Previous Bernese periacetabular osteotomy does not compromise the results of total hip arthroplasty [21]. Progression of arthritis after the procedure is related directly to the extent of arthritis present at the time of surgery [21], and there is a significant association between advanced osteoarthritis and an unsatisfactory clinical outcome [21]. In cases with large preoperative bone defects, the acetabular component was placed more superiorly in the periacetabular osteotomy group, which did not appear to affect long-term (10 year) implant survivorship [53].

Complications

Overall Complication Rates: For surgeons experienced with periacetabular osteotomy, the procedure carries a 5.9% risk of grade-III or IV complications beyond the learning curve [11]. The incidence of postoperative complications and revision surgery was not different between total hip arthroplasty and periacetabular osteotomy groups [153]. In a series of 37 patients undergoing reverse periacetabular osteotomy, the complication rate was 19% [137]. In a series of 34 hips (29 patients) undergoing periacetabular osteotomy in teenagers, 27% presented with complications or symptoms [130]. In a structured-mentorship program for a low-volume surgeon, 41 of the periacetabular osteotomies had a postoperative complication within the first 12 months of surgery [139].

Nonunion and Healing: The proportion of nonunion at a minimum of 12 months after periacetabular osteotomy was 8% [52]. At the 6-month visit, 55% of patients had not healed completely at all osteotomy sites [52]. At approximately 1 year postoperatively, 92% of patients demonstrated complete radiographic healing of all osteotomy sites [52]. In a series of teenagers, nonunion at an osteotomy site was the most common minor complication, occurring in 12% of hips at the superior pubic ramus [130]. All patients with nonunion of the superior pubic ramus in the teenage series were completely asymptomatic [130]. In a structured-mentorship program, two ischial nonunions caused painful pubic stress fractures that eventually settled [139].

Nerve Injury: Transient lateral femoral cutaneous nerve numbness occurred in 9% of hips in a series of teenagers undergoing periacetabular osteotomy [130]. In a structured-mentorship program, one temporary femoral nerve palsy and one temporary partial sciatic nerve palsy occurred as Grade II complications [139]. Both nerve injuries in the structured-mentorship program fully recovered within 3 months [139]. In a series of combined hip arthroscopy and periacetabular osteotomy, a partial sciatic nerve palsy developed in one patient and resolved on postoperative day 3 [147]. Femoral nerve palsy is particularly concerning in reverse periacetabular osteotomy because of abduction of the acetabular fragment that results in intrapelvic prominence and potential femoral nerve irritation [137].

Wound and Infection: In a series of teenagers, superficial stitch abscess occurred in 3% of hips [130]. In a structured-mentorship program, three superficial wound infections were treated using antibiotics [139]. In a series of combined hip arthroscopy and periacetabular osteotomy, one patient developed a superficial wound infection treated with oral antibiotics and another required irrigation and debridement for proximal wound dehiscence and possible infection [147]. In a structured-mentorship program, one wound infection was treated with irrigation and débridement as a Grade III complication [139].

Fractures: In a structured-mentorship program, eight isolated posterior column fractures united uneventfully [139]. In a series of combined hip arthroscopy and periacetabular osteotomy, one patient had a known intraoperative posterior column fracture [147]. Stress fracture of the inferior pubic ramus was found incidentally on routine follow-up examination in 6% of hips in a teenage series [130]. In a series of Salter innominate osteotomies, one patient suffered a fall leading to dislocation of the osteotomy and loss of correction, requiring re-operation [134].

Thromboembolism: In a series of combined hip arthroscopy and periacetabular osteotomy, a pulmonary embolism developed in one patient after noncompliance with the discontinuation of oral contraceptive medication [147].

Heterotopic Ossification: The most common complication in a series of reverse periacetabular osteotomies was heterotopic ossification resulting in surgical resection [137].

Other Considerations: Incisional hernia is a rare complication with a 0.2% incidence after periacetabular osteotomy [138]. Risk factors for incisional hernia after periacetabular osteotomy include obesity, weak abdominal muscles, and increased intraabdominal pressure [138]. In a series of combined hip arthroscopy and periacetabular osteotomy, the mean estimated blood loss was 1,064 mL (range, 300 to 2,000 mL) [147]. In a structured-mentorship program, one patient underwent removal of an irritating anterosuperior iliac spine screw as a Grade III complication [139]. In a series of Salter innominate osteotomies, five patients had dysaesthesias in the distribution of the lateral femoral cutaneous nerve [134].

Recovery

Light activity (weeks): The provided evidence does not specify a typical week range for desk work, driving, or light activities of daily living.

Full activity (months): The provided evidence does not specify a typical month range for manual work, sport, or full range-of-motion and strength return.

Complete recovery / outcome plateau (months): The provided evidence does not specify a month range for when pain, strength, and final functional outcomes stabilise.

Rehabilitation protocol: The provided evidence does not detail physical therapy phasing, immobilisation duration, weight-bearing or range-of-motion progression, or sling/brace removal timing.

Functional milestones: The provided evidence does not report validated patient-reported outcome measure trajectories or specific outcome-measure benchmarks.

Other Considerations: Appropriately selected patients undergoing periacetabular osteotomy likely experience pain relief and benefit from a delay in the onset of premature arthritis for many years [21]. Satisfactory clinical and radiographic results can be obtained after curved periacetabular osteotomy in patients fifty years of age or older with Tönnis grade-1 or 2 osteoarthritis of the hip secondary to developmental dysplasia [23]. Activity levels and hip function improve after periacetabular osteotomy in patients with borderline hip dysplasia, and participation in high-impact sports is maintained postoperatively [25]. Combined surgical dislocation and periacetabular osteotomy provides clinical improvement and intermediate-term survivorship of 85% at 10 years for patients with complex residual Legg-Calvé-Perthes deformities [38]. The majority (71%) of active patients with hip dysplasia return to presurgical or higher activity levels after open hip preservation surgery with the periacetabular osteotomy [39]. Combined periacetabular osteotomy and femoral head-neck junction osteochondroplasty produces similar early functional outcomes when compared with isolated periacetabular osteotomy [8]. The novel minimally invasive spherical periacetabular osteotomy (SPO) using patient-specific preoperative planning is a feasible technique with short-term results showing significant radiographic correction and clinical improvement, despite a high rate of transient lateral femoral cutaneous nerve palsy [54].

Key Evidence

• [L4] Periacetabular osteotomy provides pain relief and improved hip function in most patients over short- to midterm followup. [1] (10.1007/s11999-009-0842-6)
• [L5] Refinements in the periacetabular osteotomy technique and perioperative management have markedly improved the clinical outcomes and recovery in these patients. [2] (10.1016/j.arth.2017.02.015)
• [L4] Acetabular rim trimming (ART) and periacetabular osteotomy (PAO) are the best described surgical options for the treatment of AR. [3] (10.1302/2058-5241.3.180015)
• [L4] Optimal combined anteversion should be considered during periacetabular osteotomy. [4] (10.1007/s11999-015-4373-z)
• [L3] However, periacetabular osteotomy still provided excellent quality of life outcomes in a high percentage of patients, though it should only be performed in highly selected cases. [5] (10.1016/j.arth.2007.08.015)
• [L4] Periacetabular osteotomy used as a salvage procedure for patients with hip instability recalcitrant to prior arthroscopy demonstrated substantial improvement in patient-reported outcome measures and radiographic correction of acetabular coverage. [6] (10.2106/jbjs.20.00087)
• [L3] Among the scores analyzed, the HOOS appears to be the most appropriate measure of patient-reported outcome in patients undergoing periacetabular osteotomy. [7] (10.2106/jbjs.18.00185)
• [L3] This combined procedure provides effective correction of associated femoral head-neck deformities and produces similar early functional outcomes when compared with isolated periacetabular osteotomy. [8] (10.2106/jbjs.k.01038)
• [L3] Elevation of hip joint centers as much as 10 mm is one therapeutic option in the case of severe acetabular defects following total hip arthroplasty after periacetabular osteotomy. [9] (10.1007/s00402-019-03174-y)
• [L2] The Bernese periacetabular osteotomy is able to result in favourable midto long-term outcomes conditional on a stringent patient selection criteria. [10] (10.1016/j.otsr.2022.103283)
• [L4] For surgeons experienced with the periacetabular osteotomy, it is a safe procedure but is associated with a 5.9% risk of grade-III or IV complications beyond the learning curve. [11] (10.2106/jbjs.n.00113)
• [L4] However, we did note that patients with a history of periacetabular osteotomy were more likely to deliver future children by cesarean section, which could be attributable to obstetrician preference. [12] (10.1097/corr.0000000000000921)
• [Paper] When performed by an experienced surgeon, the addition of arthroscopy before periacetabular osteotomy can be done safely and does not increase the complication rate. [13] (10.1016/j.eats.2019.08.015)
• [L5] Isolated lateral rotation of the acetabular fragment should be the predominant direction of correction during periacetabular osteotomy. [14] (10.1007/s00402-020-03632-y)
• [L3] The preoperative presence of acetabular cysts did not influence the results of periacetabular osteotomy. [15] (10.1097/01.blo.0000229370.88479.76)
• [L3] Periacetabular osteotomy is an effective technique for treating symptomatic developmental dysplasia of the hip and can maintain the natural hip at least 19 years in selected patients. [16] (10.1007/s11999-008-0242-3)
• [L2] The Bernese periacetabular osteotomy can be effective for the treatment of painful hip dysplasia, but complications may be expected in as many as 15% of cases. [17] (10.2106/jbjs.j.00646)
• [L3] Sufficient acetabular reorientation, such as periacetabular rotational osteotomy, with concomitant arthroscopic debridement showed successful long-term outcomes for acetabular dysplasia in adults. [18] (10.1016/j.arth.2020.05.045)
• [L3] Periacetabular osteotomy is an effective technique to treat symptomatic hip dysplasia in selected and young patients with closed triradiate cartilage. [20] (10.1007/s11999-016-5169-5)
• [L4] [21] (10.1097/01.blo.0000128287.98083.63)
• [L5] Patients with prior nonoperative or operative treatment for dysplasia of the hip can be counseled on the potential for increased complications and incomplete correction but should be encouraged that they are likely to have good pain relief and function after periacetabular osteotomy. [22] (10.1097/corr.0000000000003200)
• [L2] Satisfactory results can be obtained clinically and radiographically after curved periacetabular osteotomy in patients fifty years of age or older with Tönnis grade-1 or 2 osteoarthritis of the hip secondary to developmental dysplasia. [23] (10.2106/jbjs.j.01126)
• [L3] We believe that THA is a reasonable surgical intervention for symptomatic dysplasia patients who have mild arthritis and do not qualify for periacetabular osteotomy. [24] (10.1016/j.arth.2024.04.060)
• [L4] Overall, activity levels and hip function improved after periacetabular osteotomy, and although more patients engaged in low-impact sports, participation in high-impact sports was maintained postoperatively. [25] (10.1177/03635465231217736)
• [L4] Single-stage combined hip arthroscopy with periacetabular osteotomy for patients with symptomatic hip dysplasia results in improvement in PROs and arthroplasty free survivorship of 92% at median 2.5 year follow-up. [26] (10.1016/j.arthro.2023.06.034)
• [Letter] While both hip arthroscopy and periacetabular osteotomy offer potential benefits for patients with borderline hip dysplasia, the authors argue for moving beyond generalized results to identify specific patient subgroups who do not do well with hip arthroscopy alone and should be considered for initial treatment with periacetabular osteotomy. [27] (10.1016/j.arthro.2025.01.057)
• [L5] Arthroscopy provides a powerful tool to successfully treat intra-articular hip pathology secondary to dysplasia while improving the bony coverage/alignment with periacetabular osteotomy; through a specialized team approach, all relevant pathology can be addressed and successful outcomes achieved. [28] (10.1016/j.arthro.2018.11.042)
• [L5] The combination of hip arthroscopy and periacetabular osteotomy is safe and effective, but clearer definitions for labral pathology and indications for repair or debridement are required. [29] (10.1016/j.arthro.2025.01.002)
• [L3] [30] (10.1007/s11999-016-5137-0)
• [L5] Surgeons should not ignore posterior hip or gluteal pain or discomfort after periacetabular osteotomy as it could originate from ischiofemoral impingement, and a proper investigation and clinical assessment can help define the source of pain. [32] (10.1097/corr.0000000000002226)
• [L4] Recognition of these distinct morphologic subtypes is important for diagnostic and surgical treatment considerations to optimize acetabular correction and avoid femoroacetabular impingement. [36] (10.1007/s11999-016-5150-3)
• [L3] Combined surgical dislocation and periacetabular osteotomy provided clinical improvement and intermediate-term survivorship of 85% at 10 years for patients with complex residual Legg-Calvé-Perthes deformities. [38] (10.2106/jbjs.21.00132)
• [L4] The majority (71%) of active patients with hip dysplasia return to presurgical or higher activity levels after open hip preservation surgery with the periacetabular osteotomy. [39] (10.1177/0363546514535906)
• [L4] The Bernese periacetabular osteotomy is currently favored for restoring pelvic anatomy with good correction and minimal secondary deformity. [40] (10.5435/00124635-200209000-00004)
• [L4] The risk from chemoprophylaxis and the development of hematoma may be greater than the risk of clinically important venous thromboembolism in patients undergoing periacetabular osteotomy. [42] (10.2106/jbjs.j.01769)
• [L4] [43] (10.1097/01.blo.0000153281.75265.1d)
• [L4] Radiological evidence of symptomatic femoroacetabular impingement was not uncommon in these Japanese patients with hip pain, with cam deformity findings being the most common. [48] (10.1302/0301-620x.96b2.32680)
• [L5] The authors encourage thorough preoperative evaluation of radiographs and advanced imaging for all patients being considered for hip arthroscopy. [49] (10.5435/jaaos-d-16-00231)
• [L5] This CORR Insights commentary argues that preservation of the intact posterior column in the Bernese periacetabular osteotomy may be responsible for persistent technical difficulties and serves no useful purpose beyond vanity, suggesting that modifying the posterior column cut plane or using alternative techniques like the Birmingham Interlocking Pelvic Osteotomy may improve outcomes. [50] (10.1097/corr.0000000000000704)
• [L5] [51] (10.1097/corr.0000000000000581)
• [L3] [52] (10.1097/corr.0000000000001296)
• [L3] In cases with large preoperative bone defects, the acetabular component was placed more superiorly in the PAO group, which did not appear to affect long-term (10 year) implant survivorship. [53] (10.1016/j.arth.2025.07.063)
• [L4] The novel minimally invasive spherical periacetabular osteotomy (SPO) using patient-specific preoperative planning is a feasible technique with short-term results showing significant radiographic correction and clinical improvement, despite a high rate of transient lateral femoral cutaneous nerve palsy. [54] (10.2106/jbjs.20.00940)
• [L3] The associations with PROMs detected in the current study suggest that muscle-induced biomechanics may have wide-reaching effects not only on loads within the hip, but also on patients' perceptions of their health and function. [57] (10.1097/corr.0000000000002728)
• [L5] A patient's age and hip shape are important factors contributing to the resulting hip mechanics, although the interplay between those mechanical factors and patient-reported outcomes of pain are unclear. [61] (10.1097/corr.0000000000000621)
• [L5] Individual and postural variations in physiologic pelvic tilt affect joint contact pressure in the hip. [72] (10.1097/corr.0000000000001737)
• [L3] Weightbearing postural radiographs are crucial for understanding hip biomechanics in hip dysplasia and refining surgical corrections during PAO. [74] (10.1177/23259671251319994)
• [L3] Hips with lower anteversion or a larger difference between anatomic and functional anteversion were more likely to be symptomatic. [75] (10.1097/corr.0000000000002768)
• [L4] Additional studies are needed to determine protective or adaptive factors in patients with abnormal anatomy who do not develop early OA and to determine whether joint preserving hip surgery extends the life of the native hip joint. [76] (10.5435/jaaos-d-16-00532)
• [L5] Hip dysplasia is a pathoanatomic osseous morphology associated with hip instability that may, in part, be due to hip capsular thickness. [77] (10.1016/j.arthro.2024.07.012)
• [L5] This finding is more pronounced with higher degrees of fragment reorientation in abduction and extension; it becomes especially pronounced in reverse PAO for acetabular retroversion or protrusio acetabuli, and might limit the ability to achieve the intended improvement in overall hip biomechanics. [80] (10.2106/jbjs.21.00454)
• [L5] From biomechanics points, RAO was more effective in relieving hip joint stress compared with shelf procedure and Chiari osteotomy. [81] (10.1186/1471-2474-15-47)
• [L5] Long-term exposure to elevated cartilage contact stresses may affect joint morphology, making hips in these individuals less amenable to joint-preservation procedures such as PAO. [84] (10.1097/corr.0000000000000715)
• [L4] Oblique inguinal incision for the anterior approach in Bernese periacetabular osteotomy is a technique that allows healing of surgical wounds without dehiscence or hypertrophic changes by respecting tension lines. [85] (10.5435/jaaosglobal-d-17-00061)
• [L4] High-level sport and combat sports are major risk factors for mechanical hip pathology in young adults, and a familial history of hip pathology is confirmed. [86] (10.1016/j.otsr.2010.09.005)
• [L5] PAO caused reductions in hip abduction and internal rotation but greater increases in hip adduction and external rotation. [88] (10.2106/jbjs.21.00405)
• [L4] Different combinations of acetabular rotations can result in large variations in femoral head coverage and hip motion, and no single combination is applicable to all cases. [90] (10.1016/j.arth.2025.04.016)
• [L4] The report supports the biomechanical principle that reorientation of the acetabulum reduces stress at the acetabular rim, shifts the os acetabuli out of the stress region, and allows union of the bony fragment with the acetabulum. [93] (10.1007/s00402-002-0431-6)
• [L5] This CORR Insights article is a commentary on a study by Wu et al. and does not present original data; it highlights that muscle-induced biomechanical variables in patients with developmental dysplasia of the hip (DDH) were associated with worse function and pain outcomes, suggesting these variables can better predict prognosis than bony anatomy alone. [94] (10.1097/corr.0000000000002787)
• [L4] [98] (10.2106/jbjs.j.01735)
• [L5] The degree of acetabular correction in the coronal plane where joint contact pressure is minimized varied among patients. [99] (10.1186/s12891-022-05005-5)
• [L5] The higher hip center gained more bone coverage but decreased the range of hip flexion and internal rotation. [100] (10.1016/j.arth.2016.03.014)
• [L5] The current evidence suggests that in patients with hip dysplasia, the problem is one of abnormal loading (a smaller weightbearing area results in higher contact stresses in those areas, resulting in cartilage breakdown). [101] (10.1097/corr.0000000000000364)
• [L3] Concomitant lumbopelvic deformity affecting the hip joint morphology could aggravate clinical symptoms leading to earlier presentation in patients undergoing PAO. [102] (10.1002/ksa.12587)
• [L5] The 3 primary factors involved with preservation of the hip joint are femoroacetabular impingement (FAI), hip dysplasia, and femoral torsion abnormalities. [104] (10.1016/j.arthro.2024.04.002)
• [L3] Patients with borderline hip dysplasia (BHD) demonstrated worse preoperative patient-reported outcome measures (PROMs) than those with frank dysplasia but experienced substantial improvement after periacetabular osteotomy (PAO). [120] (10.1016/j.jisako.2026.101166)
• [L5] Clinicians should evaluate for the Beighton score and additional radiographic factors suggestive of instability in patients with combined borderline hip dysplasia and excessive femoral anteversion, as these findings may portend inferior outcomes after arthroscopic treatment in isolation, making open procedures like periacetabular osteotomy a more reliable option for symptomatic hip instability. [121] (10.1016/j.arthro.2022.12.001)
• [L5] Hip arthroscopy for borderline hip dysplasia has a role with narrow indications, particularly in revision settings where the root cause of failure must be identified; instability-driven symptoms primarily indicate periacetabular osteotomy. [122] (10.1016/j.arthro.2024.06.026)
• [L2] Acetabular and femoral osseous abnormalities commonly are associated with labral tears, and recognition of these abnormalities is important to optimize surgical treatment of patients with symptomatic labral disease. [123] (10.1097/01.blo.0000181147.86058.74)
• [L5] The windshield wiper sign is a new radiographic instability sign visible on plain radiographs, MRI, and arthroscopy that predicts hip instability and allows for the planning of combined arthroscopic cartilage therapy and periacetabular osteotomy. [125] (10.1016/j.arthro.2024.06.003)
• [L5] [126] (10.5435/00124635-199709000-00006)
• [L5] The authors propose a diagnostic framework that groups symptomatic dysplastic hips into one of 3 categories based on the primary direction of instability: anterior, posterior, and global, to aid clinicians in developing a differential diagnosis and planning appropriate surgical management. [127] (10.1016/j.arth.2017.02.067)
• [L4] [130] (10.1007/s00264-015-2973-6)
• [L4] [132] (10.1097/corr.0000000000001547)
• [L3] [133] (10.1016/j.arthro.2020.05.049)
• [L4] [134] (10.1007/s004020050387)
• [L4] [137] (10.1097/corr.0000000000001549)
• [L4] Incisional hernia is a rare complication (0.2% incidence) after periacetabular osteotomy, with risk factors including obesity, weak abdominal muscles, and increased intraabdominal pressure. [138] (10.1097/01.blo.0000130203.28818.da)
• [L4] [139] (10.1097/corr.0000000000000571)
• [L4] Coronal femoroacetabular distance and limbus thickness on post-reduction MRI help predict hips that will have residual acetabular dysplasia in the long term after closed or open reduction. [141] (10.2106/jbjs.23.00333)
• [L4] Preoperative MRI evaluation of femoral anteversion is recommended as essential rather than adjunctive. [142] (10.1007/s00402-009-1020-8)
• [L3] They may be used for radiographic evaluation of symptomatic hips, may offer possible predictors for surgical outcomes, and serve to guide clinical decision-making. [143] (10.1007/s11999-014-4038-3)
• [L4] [147] (10.1016/j.arthro.2015.06.002)
• [L5] [148] (10.5435/jaaos-d-24-00340)
• [L3] [149] (10.1007/s00167-014-3297-6)
• [L1] The incidence of postoperative complications and revision surgery was not different between THA and PAO groups. [153] (10.1016/j.otsr.2020.08.012)

See Also

• Hip arthroscopy
• Femoroacetabular impingement
• Hip osteoarthritis

References

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