Acetabular morphology in slipped capital femoral epiphysis: comparison at treatment onset and skeletal maturity.

PURPOSE: To investigate changes in acetabular morphology during the follow-up of slipped capital femoral epiphysis (SCFE) and search for factors associated with acetabular dysplasia at skeletal maturity. METHODS: We evaluated 108 patients with unilateral SCFE (mean age at slip, 12.3 years sd 1.7) to skeletal maturity, with a minimum follow-up of two years (median 4.5 years; interquartile range 3.2 to 6.2). Acetabular parameters obtained from initial and most recent radiographs included the lateral centre-edge angle (LCEA), Tönnis angle (TA) and acetabular depth-width ratio (ADR). Acetabular dysplasia was considered for LCEA < 20° or TA > 10°. Femoral parameters consisted of the most recent head diameter, neck-shaft angle, neck length, articulotrochanteric distance and alpha angle. RESULTS: At SCFE onset, the affected hip showed a slightly lower LCEA (26.4° sd 6.1° versus 27.3° sd 5.7°; p = 0.01) and ADR (330 sd 30 versus 340 sd 30; p < 0.001) compared with the uninvolved hip. At final follow-up, the affected hip showed lower LCEA (24.5° sd 7.6° versus 28.8°sd 6.6°; p < 0.001) and ADR (330 sd 40 versus 350 sd 40; p < 0.001), and TA was larger (5.5° sd 5.4° versus 2.3° sd 4.2°; p < 0.001) compared with the uninvolved hip. Acetabular dysplasia was observed in 27 (25%) of 108 hips with SCFE. Femoral head overgrowth, age at slip and SCFE severity were independent factors associated with acetabular dysplasia (p < 0.05). CONCLUSION: Acetabular coverage and depth are not increased in SCFE, and the acetabular coverage tends to decrease up to skeletal maturity. A potential disturbance in the acetabular growth and remodelling exists mainly for young children with severe SCFE, and a potential for acetabular insufficiency may be observed at the diagnosis and follow-up of SCFE. LEVEL OF EVIDENCE: Prognostic Level IV.

Periacetabular osteotomy to treat residual dysplasia in adolescents and young adults: indications, complications, results.

PURPOSE: Discuss current indications, techniques, complications and results of periacetabular osteotomy (PAO) to treat the adolescent and young adult with symptomatic acetabular dysplasia or the rare minimally symptomatic patient with dysplasia with a guarded prognosis without PAO surgery. METHODS: Review of clinical experience with PAO at our and other high-volume centres. RESULTS: At a mean follow-up of 18 years after PAO, more than 75% of hips are preserved. At 30-year follow-up, longest term reported series notes survival of one-third of hips. CONCLUSION: Both middle- and long-term results suggest efficacy of PAO in improving function and prognosis in most symptomatic adolescent and young adult patients with spherically congruous pre-arthritic dysplastic hips.

SCFE: clinical aspects, diagnosis, and classification.

PURPOSE: This article seeks to improve treatment outcomes in slipped capital femoral epiphysis (SCFE) by outlining advances in diagnosis, understanding of pathomechanics, and mechanically-based classification. METHODS: Review of clinical experience with SCFE at our high-volume centre, interaction with other clinical experts, and literature review has allowed a current perspective to be articulated. RESULTS: SCFE remains an important clinical problem, with late diagnosis still frequent. Improved understanding of the ubiquity of femoroacetabular impingement has guided current classification and treatment protocols. CONCLUSION: SCFE is an important clinical problem, with high historical rates of impaired hip function both in childhood and adulthood. Great opportunities exist for improved outcomes following earliest possible clinical diagnosis, modern imaging, and mechanically-based classification of involved hips to allow optimal treatment.

Decreased and increased relative acetabular volume predict the development of osteoarthritis of the hip: an osteological review of 1090 hips.

AIMS: Recently, there has been considerable interest in quantifying the associations between bony abnormalities around and in the hip joint and osteoarthritis (OA). Our aim was to investigate the relationships between acetabular undercoverage, acetabular overcoverage, and femoroacetabular impingement (FAI) with OA of the hip, which currently remain controversial. MATERIALS AND METHODS: A total of 545 cadaveric skeletons (1090 hips) from the Hamann-Todd osteological collection were obtained. Femoral head volume (FHV), acetabular volume (AV), the FHV/AV ratio, acetabular version, alpha angle and anterior femoral neck offset (AFNO) were measured. A validated grading system was used to quantify OA of the hip as minimal, moderate, or severe. Multiple linear and multinomial logistic regression were used to determine the factors that correlated independently with the FHV, AV, and the FHV/AV ratio. RESULTS: Female cadavers had smaller FHVs (standardised beta -0.382, p < 0.001), and AVs (standardised beta -0.351, p < 0.001), compared with male patients, although the FHV/AV ratio was unchanged. Every 1° increase in alpha angle increased the probability of having moderate OA of the hip compared with minimal OA by 7.1%. Every 1 mm decrease in AFNO increased the probability of having severe or moderate OA of the hip, compared with minimal OA, by 11% and 9%, respectively. The relative risk ratios of having severe OA of the hip compared with minimal OA were 7.2 and 3.3 times greater for acetabular undercoverage and overcoverage, respectively, relative to normal acetabular cover. CONCLUSION: Acetabular undercoverage and overcoverage were independent predictors of increased OA of the hip. The alpha angle and AFNO had modest effects, supporting the hypothesis that bony abnormalities both in acetabular dysplasia and FAI are associated with severe OA. Cite this article: Bone Joint J 2017;99-B:432-9.

Obesity is a major risk factor for the development of complications after peri-acetabular osteotomy.

Obesity is a risk factor for complications following many orthopaedic procedures. The purpose of this study was to investigate whether obesity was an independent risk factor increasing the rate of complications following periacetabular osteotomy (PAO) and to determine whether radiographic correction after PAO was affected by obesity. We retrospectively collected demographic, clinical and radiographic data on 280 patients (231 women; 82.5% and 49 men; 17.5%) who were followed for a mean of 48 months (12 to 60) after PAO. A total of 65 patients (23.2%) were obese (body mass index (BMI) > 30 kg/m(2)). Univariate and multivariate analysis demonstrated that BMI was an independent risk factor associated with the severity of the complications. The average probability of a patient developing a major complication was 22% (95% confidence interval (CI) 11.78 to 38.21) for an obese patient compared with 3% (95% CI 1.39 to 6.58) for a non-obese patient The odds of a patient developing a major complication were 11 times higher (95% CI 4.71 to 17.60, p < 0.0001) for an obese compared with a non-obese patient. Following PAO surgery, there was no difference in radiographic correction between obese and non-obese patients. PAO procedures in obese patients correct the deformity effectively but are associated with an increased rate of complications.

Patterns of joint damage seen on MRI in early hip osteoarthritis due to structural hip deformities.

OBJECTIVE: The aim of this study was to evaluate differences in damage patterns assessed using magnetic resonance imaging (MRI) between hips with femoroacetabular impingement (FAI) and developmental dysplasia of the hip (DDH) as well as to correlate MRI findings with delayed Gadolinium enhanced MRI of cartilage (dGEMRIC) and with patient pain. DESIGN: This retrospective study included 40 patients (mean age 28.6 ± 11.2 years) who underwent dGEMRIC and morphological MRI of the hip. Twenty-one hips with FAI and 19 with DDH were investigated. A self-developed morphological grading (MRI score) and dGEMRIC evaluation were done on seven radial reformats obtained from an isotropic 3D True-fast imaging with steady state precession (FISP) sequence and an isotropic T1-mapping sequence. The observed damage patterns were summed up into sub-scores and a total MRI score. RESULTS: Labrum damage, paralabral cysts, and acetabular rim bone cysts were more common in DDH patients than in FAI patients. No significant differences were seen in the occurrence of cartilage damage, bone cysts, or osteophytes. In DDH (but not in FAI), the dGEMRIC index demonstrated a tendency for lower values in areas next to cartilage defects. There was no association between labrum damage and dGEMRIC index. A moderate correlation was seen between Western Ontario and McMaster Universities (WOMAC) pain score and cartilage damage, paralabral cysts, and the total MRI score. CONCLUSIONS: This study confirms a higher prevalence of labrum damage but not cartilage damage in patients with DDH in comparison to patients with FAI. In addition, our data suggests an association of cartilage damage and paralabral cysts with patient reported pain.

Bernese periacetabular osteotomy in males: is there an increased risk of femoroacetabular impingement (FAI) after Bernese periacetabular osteotomy?

BACKGROUND: The Bernese periacetabular osteotomy (PAO) is a popular option for treating symptomatic acetabular dysplasia. We noted symptomatic impingement after PAO in several male patients. QUESTIONS/PURPOSES: We therefore determined (1) the incidence of clinical signs of FAI after PAO in the male population; and (2) whether any factors were associated with the positive impingement signs after PAO in males. PATIENTS AND METHODS: We retrospectively reviewed 38 males who underwent 46 periacetabular osteotomies (PAO) between 2000 and 2007. Clinical and radiographic data were analyzed with the focus on pre- and postoperative incidence of femoroacetabular impingement. Minimum followup was 12 months (average, 43 months; range, 12-90 months). RESULTS: We found a positive impingement sign in 19 of the 46 hips during the preoperative examination compared to 22 (47.8%) hips postoperatively. The ROM (flexion and internal rotation) decreased postoperatively compared to preoperatively. Radiographic parameters of coverage LCE-, ACE- and Tönnis angle improved into the normal range. Twenty hips had postoperative heterotopic ossification to varying degrees, mostly minor. WOMAC scores improved in the function and pain domains postoperatively. CONCLUSIONS: Despite normalization of coverage we found a high postoperative rate of clinical signs of FAI after PAO in males. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

[Slipped capital femoral epiphysis]. / Epiphysenlösung.

Slipped capital femoral epiphysis (SCFE) is a common hip disorder in adolescence and should be diagnosed and treated surgically as soon as possible. The etiology, biomechanical, biochemical and hereditary factors are still under investigation. The classification of SCFE is based on the acuteness, clinical and radiomorphological findings. Avascular necrosis of the epiphysis (AVN) and chondrolysis occur more often in operated than in non-operated patients. Medium and long-term sequelae of SCFE are loss of function and degenerative joint disease due to femoroacetabular impingement (FAI) or consequences from complications such as AVN and chondrolysis. For mild slips the long-term prognosis is better than for moderate or severe slips. Higher grade unstable SCFE may benefit from reduction while in chronic slips corrective osteotomy may be indicated. Traditional osteotomy procedures, such as Imhäuser or Southwick intertrochanteric osteotomy are safe procedures but correct the deformity distant from the site of the deformity. The surgical dislocation with modified Dunn osteotomy according to Ganz allows the preparation of an extended retinacular soft tissue flap and offers an extensive subperiosteal exposure of the circumference of the femoral neck before reducing the slipped epiphysis anatomically. In cases of FAI due to mild deformities restoration of the head-neck offset via hip arthroscopy or surgical dislocation should be considered before higher grade cartilage damage occurs.

[Delayed gadolinium enhanced MRI of cartilage (dGEMRIC): molecular MRI of hip joint cartilage]. / "Delayed Gadolinium Enhanced MRI of Cartilage" (dGEMRIC): Molekulare MRT-Bildgebung des Hüftgelenkknorpels.

Factors such as instability and impingement lead to early cartilage damage and osteoarthritis of the hip joint. The surgical outcome of joint-preserving surgery about the hip joint depends on the preoperative quality of joint cartilage.For in vivo evaluation of cartilage quality, different biochemically sensitive magnetic resonance imaging (MRI) procedures have been tested, some of which have the potential of inducing a paradigm shift in the evaluation and treatment of cartilage damage and early osteoarthritis.Instead of reacting to late sequelae in a palliative way, physicians could assess cartilage damage early on, and the treatment intensity could be adequate and based on the disease stage. Furthermore, the efficiency of different therapeutic interventions could be evaluated and monitored.This article reviews the recent application of delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) and discusses its use for assessing cartilage quality in the hip joint. dGEMRIC is more sensitive to early cartilage changes in osteoarthritis than are radiographic measures and might be a helpful tool for assessing cartilage quality.

Periacetabular osteotomy in patients with Down's syndrome.

We treated eight dysplastic acetabula in six skeletally mature patients with Down's syndrome by a modified Bernese periacetabular osteotomy. The mean age at the time of surgery was 16.5 years (12.8 to 28.5). Mean length of follow-up was five years (2 to 10.4).Pre-operatively the mean (Tonnis) acetabular angle was 28 degrees, the centre-edge angle was -9 degrees, and the extrusion index was 60%; post-operatively they were 3 degrees, 37 degrees, and 17%, respectively. Two patients with post-operative (Tonnis) acetabular angles > 10 degrees developed subluxation post-operatively and required secondary varus derotation femoral osteotomies. Another patient developed a late labral tear which was treated arthroscopically. All eight hips remain clinically stable, and are either asymptomatic or symptomatically improved. These results suggest that the modified Bernese periacetabular osteotomy can be used successfully in the treatment of acetabular dysplasia in patients with Down's syndrome.

Early failure of Pavlik harness treatment for developmental hip dysplasia: clinical and ultrasound predictors.

A cohort of 93 patients with developmental dysplasia of the hip (DDH) treated with a Pavlik harness were evaluated to determine predictors of treatment failure. Failure was defined as failure to achieve or maintain hip reduction in the Pavlik harness. Of 93 patients (137 hips), 17 (26 hips) failed Pavlik harness treatment. Univariate risk factors for failure included bilaterality, initial clinical exam, and initial ultrasound (US) percent coverage. Clinical exam and initial percent coverage were multivariate risk factors for failure. Among initially clinically dislocatable hips, a low initial US alpha angle correlated with an increased likelihood of failure. All (6/6) patients with an initially irreducible hip and an initial coverage of <20% by US eventually failed treatment. Gender, side of pathology, and age at diagnosis and initiation of treatment did not correlate with failure. Irreducibility by physical exam combined with US coverage of <20% identified a patient group that uniformly failed Pavlik harness treatment. These patients may be candidates for alternative bracing, traction, or closed or open reduction.

Osteonecrosis of the femoral head associated with slipped capital femoral epiphysis.

We performed a retrospective analysis of 212 patients (299 hips) with slipped capital femoral epiphysis (SCFE) over a 9-year period to assess the incidence of osteonecrosis of the femoral head. Risk factors for the occurrence of osteonecrosis and the influence of treatment on the development of osteonecrosis were determined. Osteonecrosis occurred in 4 hips with unstable SCFE (4/27) and did not occur in hips with stable SCFE (0/272). The proportion of hips in which osteonecrosis developed was significantly higher among the unstable hips (4/27 vs. 0/272, p < 0.0001). Among those with an unstable hip, younger age at presentation was a predictor of a poorer outcome. Magnitude of the slip, magnitude of reduction, and chronicity of the slip were not predictive of a poorer outcome in the unstable group. In situ fixation of the minimally or moderately displaced "unstable" SCFE demonstrated a favorable outcome. We have identified the hip at risk as an unstable SCFE. The classification of hips as unstable if the epiphysis is displaced from the metaphysis or if the patient is unable to walk is most useful in predicting a hip at risk for osteonecrosis.

Wagner multiple K-wire osteosynthesis to correct coxa vara in the young child: experience with a versatile 'tailor-made' high angle blade plate equivalent.

In 1978, Wagner described a technique using multiple Kirschner wires (K-wires) to stabilize an intertrochanteric osteotomy performed for the correction of coxa vara in small children. Multiple K-wires are used to create a custom high-angle blade plate for valgus osteotomy. The authors have evaluated a retrospective series of 17 Wagner intertrochanteric osteotomies that were performed in 10 children with coxa vara between the ages of 1 year and 8 years. The neck-shaft angle was corrected from 93.5 degrees to 129.5 degrees at long-term follow-up, and the Hilgenreiner epiphyseal angle was corrected from 71 degrees to 37.6 degrees at long-term follow-up. Revision surgery was performed on five hips with inadequate initial surgical correction. Complications included a single broken K-wire, a femur fracture after hardware removal, and one hip developed avascular necrosis postoperatively.

[Computer-assisted planning of corrective osteotomies in cases of epiphysiolysis capitis femoris]. / Computerassistierte Planung von Umstellungsosteotomien in Fällen von Epiphysiolysis capitis femoris]

Slipped capital femoral epiphysis (SCFE) leads to an unphysiologic function in adolescent hips. Evaluation of the slippage as well planning of corrective osteotomies is a major three-dimensional (3D) problem. Therefore, the current clinical evaluation, which is based on biplanar plain radiographs, cannot be satisfying. More is needed than simply measuring the femoral geometry to evaluate the impact of a slippage onto the physiologic hip function. We have developed a computer-based system for planning and evaluation of reorienting osteotomies in severe cases of SCFE. In our system, CT-based 3D computer models of the hip are used to simulate the range of motion within physiologic cartilage-to-cartilage contact. This helps to visualize and quantify the early impingement due to the slippage. In addition, 3D techniques allow to simulate and plan the corrective osteotomy in an intuitive way on the computer screen. Using the same range of motion system mentioned above, the projected result can be evaluated quantitatively and compared to other approaches. The motion simulation is based on the surface geometry of the joint partners rather than on a predefined, fixed rotation center. The presented system allows a much more intuitive and appropriate system for indicating and planning corrective osteotomies than conventional methods.

Impingement simulation of the hip in SCFE using 3D models.

OBJECTIVE: Affecting as it does the geometry of adolescent hips, slipped capital femoral epiphysis (SCFE) and its evaluation represent a major three-dimensional problem. The current methods of clinical assessment-geometric measurements of the femur on plain radiographs or on axial computed tomographic (CT) cross-sections-address only one of the two joint components. MATERIALS AND METHODS: We have developed a system to simulate motion of hip joints with physiologic joint contact. In our system, CT-based computer models of the femur, pelvis, etc., are fitted with oriented bounding boxes (OBBs) and manipulated. Collision detection algorithms control the hip motion, which, in this virtual joint, is based on the surface geometry of the joint partners rather than on a predefined fixed rotation center. RESULTS: An illustrative case is presented to show the advantages of the new biomechanical evaluation method over conventional radiological assessments for SCFE. The proposed system provides remarkably high speed, and the necessary data can be prepared in a reasonable time. CONCLUSION: The range-of-motion assessment provides the surgeon with information about the site and the impact of nonphysiologic contact in the hip joint. The information thus obtained can be valuable for indication and planning of corrective surgery in cases of SCFE.

Spinal deformity after selective dorsal rhizotomy in patients with cerebral palsy.

Selective dorsal rhizotomy is used widely as a means of treating spasticity associated with cerebral palsy. Little is known regarding the effect of the procedure on the development or progression of spinal deformity. The authors reviewed six patients with progressive deformity after rhizotomy. Prerhizotomy and postrhizotomy records of physical examinations and radiographs were reviewed retrospectively in an attempt to identify risk factors for development of and/or rapid progression of, spinal deformity. Detailed preoperative and postoperative evaluation of spinal alignment should be undertaken, particularly in those patients who may be at risk of rapidly progressive deformity.

Periacetabular osteotomy without abductor dissection using direct anterior exposure.

The direct anterior exposure is a new abductor sparing surgical approach to perform periacetabular osteotomy, developed in an effort to eliminate the postoperative abductor morbidity associated with the classic Smith-Petersen approach. The direct anterior exposure also allows anterior arthrotomy of the hip joint, necessary to deal with intraarticular disease of the acetabular rim that is common in adult patients who require periacetabular osteotomy. The direct anterior exposure combines the medial portion of the classic Smith-Petersen iliofemoral exposure with or without the second window of the ilioinguinal exposure. An osteotomy of the anterior superior spine is done routinely to facilitate the approach by relaxing the attached sartorius and inguinal ligament origins. The authors' experience with the direct anterior exposure involves 195 consecutive periacetabular osteotomies done since 1992, with 60 operations done using the full approach through two windows and 135 operations done using the limited approach through one window. There was no difference in functional or radiographic results, with both approaches allowing rapid functional recovery, excellent radiographic corrections, rapid bony healing, and minimal formation of heterotopic bone. No osteonecrosis or vascular injuries were seen. In nearly all patients, abductor function had returned to preoperative levels by 3 months after surgery, in distinct contrast to the authors' previous experience with the Smith-Petersen approach. The authors consider the direct anterior exposure to be the surgical approach of choice for periacetabular osteotomy, with the more limited version proving satisfactory in all patients except the largest and most muscular patients. The full version is useful in large male patients.

Planning acetabular redirection osteotomies based on joint contact pressures.

Acetabular redirection osteotomy can be used to relieve pain, improve function, and extend the life of dysplastic hip joints. To understand better the factors that may determine the acetabular reorientation that minimizes pressures, joint contact pressures were calculated by computer assisted methods in 70 dysplastic and 12 normal hips (82 patients). Calculated pressures were consistent with pressures estimated and measured by other investigators. Contact areas were 26% smaller, and contact pressures were 23% higher, in the dysplastic hips compared with the normal hips. When the acetabula were reoriented to minimize contact pressures for an activity such as the midstance phase of gait, then contact pressures were elevated for dissimilar activities such as stair ascent. Contact pressures in the dysplastic hips were reduced when the acetabula were rotated in the frontal plane to increase lateral coverage or rotated in the sagittal plane to increase anterior coverage. In most of the dysplastic hips, contact pressures were reduced twice as much when the acetabulum was rotated in the frontal and the sagitta' planes. Computer assisted methods to quantify joint contact pressures can be used to assess potential candidates for reconstruction, plan acetabular redirection surgery, and possibly may improve the long term success of acetabular redirection osteotomy.

Surgical correction of acetabular dysplasia in the adult. A Boston experience.

Acetabular redirection surgery is the mainstay of treatment for the symptomatic, dysplastic hip. The authors' experience with the Salter innominate osteotomy, Wagner spherical acetabular osteotomy and the modified Bernese periacetabular osteotomy shows that major acetabular redirection surgery can reliably improve the structure of the dysplastic hip and delay or prevent secondary osteoarthrosis. The limited correction achieved by the Salter innominate osteotomy suggests this procedure generally should be reserved for younger patients with mild dysplasia. The modified Bernese periacetabular osteotomy is the authors' current preferred method of treating acetabular dysplasia, even in the presence of mild to moderate secondary osteoarthrosis.

Gadolinium-enhanced MR imaging of pediatric patients after reduction of dysplastic hips: assessment of femoral head position, factors impeding reduction, and femoral head ischemia.

OBJECTIVE: We describe gadolinium-enhanced MR imaging of position and vascular enhancement of the femoral head in pediatric patients who have undergone reduction of hip dislocation. SUBJECTS AND METHODS: Within 24 hr of hip reduction and spica casting, we performed 25 gadolinium-enhanced MR studies in 18 infants and young children (15 girls, three boys) with 23 dysplastic hips. All but two patients underwent closed reductions. We evaluated intraoperative arthrograms for obstacles to reduction and subsequent radiographs for avascular necrosis. RESULTS: MR images showed that all femoral heads were in their respective acetabula, but several structures interfered with concentric reduction. Obstacles to reduction included a pulvinar (n = 16), infolding of the capsule (n = 9), interposition of the labrum (n = 2), and a hypertrophied ligamentum teres and transverse ligament (n = 2). All 50 femoral heads showed enhancement: 35 normally, 10 homogeneously but less than on the contralateral femoral head or the ipsilateral greater trochanter, and five with areas of focally decreased enhancement. Hips that showed decreased enhancement had undergone greater degrees of abduction (r = .38, p < .01). CONCLUSION: Gadolinium-enhanced MR imaging can reveal abnormalities of hip position and proximal femoral epiphyseal and physeal vascularity that can occur after hip reduction. Abnormalities of enhancement were more frequent in patients who had greater femoral abduction. The effect of decreased epiphyseal vascular enhancement is still uncertain.