This study aimed to investigate the correlation between ossific nucleus volume and avascular necrosis (AVN) in pediatric patients diagnosed with developmental dysplasia of the hip (DDH). Analyzing 211 cases, including 119 open reduction (OR) and 92 closed reduction (CR) procedures, we quantified ossific nucleus volume using magnetic resonance imaging (MRI). Categorizing the OR group based on ossific nucleus volume revealed no statistically significant difference in AVN incidence. Similarly, in the CR cohort, there was no significant discrepancy in AVN occurrence between subgroups with or without the ossific nucleus. Logistic regression in CR identified the international hip dysplasia institute (IHDI) grade as a significant AVN risk factor (p = 0.007). IHDI grades 3 and 4 exhibited a 6.94 times higher likelihood of AVN compared to grades 1 and 2. Across CR and OR, neither initial age nor ossific nucleus volume emerged as AVN risk factors. In conclusion, ossific nucleus volume does not pose a risk for AVN in DDH children undergoing CR or OR, emphasizing the clinical significance of IHDI grading in predicting AVN risk during CR and the importance of early intervention to prevent treatment delays.

The acetabular sourcil is commonly interpreted as a reliable radiographic representation of the weightbearing dome of the acetabulum, despite limited modern data. Assessment of weightbearing acetabular coverage has been described using both the sourcil edge and bone edge as anatomic landmarks, leading to confusion and potential misguidance in surgical decision-making and thus compromised patient outcomes.

The purpose of this study was to characterize the 3-dimensional (3D) anatomic correlates of the sourcil-edge and bone-edge radiographic measurements on false-profile radiographs. It was hypothesized that the sourcil edge would represent anterolateral coverage and the bone edge would represent anterior coverage.

Descriptive laboratory study.

A total of 80 hips were grouped by large or small differences between bone-edge and sourcil-edge anterior center-edge angles, based on upper and lower quartiles of discrepancy. Three-dimensional surface mesh models and digitally reconstructed radiographs were generated from hip computed tomography scans. Sourcil-edge and bone-edge anterior center-edge angles were identified on digitally reconstructed radiographs and registered to the 3D models with fiducial markers. Intersections of bone-edge and sourcil-edge projection lines with the acetabular rim were obtained from the 3D models.

The bone-edge and sourcil-edge projections intersected the acetabular rim at clockface means of 2:05 ± 0:22 and 1:12 ± 0:25, respectively. The 3D models consistently demonstrated that, in both large- and small-discrepancy groups, the sourcil edge corresponded to the acetabular area just posterior to the anterior inferior iliac spine (AIIS) projection, and the bone edge corresponded to the weightbearing region inferior to the AIIS. Additionally, in large-discrepancy hips, the bone edge corresponded to more prominent acetabular coverage in the region inferomedial to the AIIS when compared with the small-discrepancy hips.

On false-profile radiographs, the sourcil edge corresponds to superior femoral head coverage, and the bone edge corresponds to anterosuperior coverage. Radiographs with a large discrepancy between sourcil-edge and bone-edge measurements demonstrate acetabular rim prominence in the region of the AIIS.

Characterizing the anatomic weightbearing regions of the acetabulum represented on false-profile radiographs facilitates improved clinical and intraoperative decision-making in hip preservation surgery, including acetabuloplasty and periacetabular osteotomy.

» Anatomic disorders of the acetabular rim are a common, correctable source of hip pain in younger patients.» Some common conditions of involving abnormal acetabular rim morphology include developmental dysplasia of the hip, pincer-type femoroacetabular impingement, acetabular protrusion, and acetabular retroversion.» Treatment option for these conditions were historically limited to open osteotomy and osteoplasty procedures; however, there is increasing use of arthroscopic intervention for these patients.» Arthroscopic intervention has demonstrated short-term success in a variety of focal acetabular rim disorders; however, further research is needed to determine the long-term outcomes of these procedures and their utility in more global pathology.

The objective of this study was to evaluate the incidence of avascular necrosis (AVN) of the femoral head in children less than 3 years of age with developmental dysplasia of the hip (DDH) treated with closed reduction, open reduction alone and open reduction combined with osteotomy. We reviewed clinical trials from the PubMed, EMBASE and Cochrane Library databases (up to November 2020) that were related to closed reduction, open reduction alone and open reduction combined with osteotomy for the treatment of children under 3 years of age with DDH. The screening and quality evaluation of the literature were performed independently by two researchers. In case of disagreement, a third researcher resolved the discourse. Finally, the data were extracted, and the R software and GeMTC program package were used to conduct a network meta-analysis (NMA). The evaluation index was the incidence of AVN. Fourteen articles were included. The NMA showed that in terms of the incidence of AVN, cases treated with open reduction alone were higher than those with closed reduction, and the difference was statistically significant. Open reduction alone had the highest probability (94.4%) of having the highest incidence of AVN, followed by open reduction combined with osteotomy (5.5%) and closed reduction (0.1%). In the treatment of children with DDH who are younger than 3 years old, open reduction alone is most likely to be the treatment with the highest incidence of AVN, followed by open reduction combined with osteotomy. The closed reduction had the smallest probability of AVN.

The objective of this study was to compare outcomes following open reduction with and without femoral shortening when treating patients aged 2-3 years with Tönnis grade III developmental dysplasia of the hip (DDH). In this prospective study, 78 patients (6 boys and 72 girls; mean age: 27.8 months; age range: 24-35 months) with Tönnis grade III DDH at our hospital from January 2014 to August 2017 were included. There were 34 hips in the without femoral shortening group and 44 hips in the femoral shortening group. Clinical outcomes were rated using the modified McKay criteria, and the hips were graded using the Severin score. Avascular necrosis (AVN) and redislocation were assessed. Mean follow-up was 26.5 months (range 17-32 months). In the without femoral shortening group (n = 34), there were five patients with AVN (14.7%), and 30 scored excellent and 4 scored good results per the modified McKay criteria. Further, 28 excellent and six good results were obtained using the Severin scale; no patient had redislocation. In the femoral shortening group(n = 44), there were seven patients with AVN (15.9%), and 38 scored excellent and six scored good results per the modified McKay criteria. Further, 31 excellent and 13 good results were obtained using the Severin scale; no patient had redislocation. Additionally, there were no statistically significant differences based on Modified McKay criteria, Severin score and AVN rate. Femoral shortening is not required for children aged 2-3 years with Tönnis grade III DDH.

The importance of precisely understanding the pathoanatomy of acetabular dysplasia prior to surgical treatment has long been recognized. Acetabuloplasties for neuromuscular hip dysplasia have typically aimed to improve the acetabulum by increasing posterior-superior coverage, as previous three-dimensional (3-D) computed tomography (CT) studies have shown that acetabular dysplasia in neuromuscular hips is primarily in the direction of posterior-superior subluxation or dislocation. The purpose of this study was to identify differences in 3-D morphology between normal hips and dysplastic neuromuscular hips, specifically to identify areas of acetabular deficiency to guide preoperative decision-making. Patients treated for neuromuscular hip dysplasia at a single institution between 2009 and 2017 with a preoperative high-resolution pelvic CT scan (28 hips) were evaluated with custom software to measure acetabular morphology. Acetabuli were divided into equal octants; coverage angles were measured for each octant of interest. Variables were compared with age- and sex-matched normal controls (56 hips). We found a wide range of hip pathology in our study cohort. Five hips had no sectors with abnormal coverage. One hip (4%) was overcovered anteriorly. The remaining pathology was undercoverage located anteriorly [n = 7 (25%)], superiorly [n = 6 (21%)], posteriorly [n = 4 (14%)] or globally [n = 5 (18%)]. Our findings indicate that individual patients with neuromuscular acetabular dysplasia have unique deformities that do not uniformly conform to a specific area of acetabular deficiency. It is imperative to define the specific 3-D acetabular deficiency location and magnitude for accurate preoperative planning. Level of evidence: Level III.

Hip dysplasia (HD) is common in both humans and dogs. This interconnection is because humans and dogs descended from a common ancestor and therefore have a similar anatomy at micro- and macroscopic levels. Furthermore, dogs are the animals of choice for testing new treatments for human hip dysplasia and orthopedic surgery in general. However, little literature exists comparing HD between the two species. Therefore, the aim of this review is to describe the anatomy, etiology, pathogenesis, diagnostics, and treatment of HD in humans and dogs. HD as an orthopedic condition has many common characteristics in terms of etiology and pathogenesis and most of the differences can be explained by the evolutionary differences between dogs and humans. Likewise, the treatment of HD shows many commonalities between humans and dogs. Conservative treatment and surgical interventions such as femoral osteotomy, pelvic osteotomy and total hip arthroplasty are very similar between humans and dogs. Therefore, future integration of knowledge and experiences for HD between dogs and humans could be beneficial for both species.

Ganz periacetabular osteotomy (PAO) is a technically demanding surgical procedure. It requires cutting around the acetabulum to mobilize it under fluoro- scopic control. The radiolucent table and good quality imaging are mandatory to perform this osteotomy in a safe way. Modification of Ganz osteotomy was developed a with minimal soft tissue exposure using intra-pelvic approach which allows direct visualization of the quadrilateral plate. The purpose of the present study was to review the early results in the initial group of patients who had this procedure. The Ganz PAO was performed on 8 cases painful dysplastic hips, using the intra-pelvic approach through the Pfannenstiel incision. All of the osteotomies were performed under fluoroscopic control and direct visualizing the osteotomy site from the same incision. The acetabular fragment was medialized and redirected anterolaterally then fixed with 3 screws. The pre-operative Harris hip score mean was 66.8 and improved to be 92.7 (p value <0.0005) and this was statistically significant. Radiologically the CEA improved in the pre-operative X-ray from mean of 13.12 degree to 28.37 degrees (p value <0.0005) and this was statistically significant. Painful dysplastic hips should be treated before function becomes seriously impaired. The Ganz osteotomy through an intra-pelvic approach, can be done with minimal exposure to radiation in a relatively short time.

Hip dysplasia (HD) is one of the most common hereditary orthopaedic diseases in dogs, with serious implications for the quality of life of the affected animals. Radiographic screening is essential for the selection of breeding stock in some at-risk breeds, and radiography is also used in the diagnosis of clinical HD cases. A definitive diagnosis of HD is based on radiographic examination, and the most commonly used view is the ventrodorsal hip extended projection, sometimes in combination with various hip stress-based techniques. Radiographic images require high quality positioning and dogs are usually anesthetized and often manually restrained to facilitate optimal positioning. The 'as low as reasonably achievable' (ALARA) principle used in human radioprotection is not always fulfilled in veterinary practice, except in the UK, where human exposure to ionizing radiation in veterinary medicine is strictly regulated. While each dose of ionizing radiation is small, doses accumulate over a lifetime, which can eventually result in substantial radiation exposure. Therefore, manual restraint should be avoided and mechanical immobilization, sedation or general anaesthesia should be used. This review examines the biological effects of human exposure to ionizing radiation and common sources of veterinary exposure. The diagnostic quality of imaging methods for the diagnosis of canine HD is compared between manually restrained and hands-free dog positioning. Hands-free radiographic techniques are available to assess hip laxity, degenerative joint changes and hip osseous structure while preserving image quality, and can be used to select animals for breeding or for the diagnosis of HD.

The purpose of this study is to determine if a quantitative method can be used to identify differences in 3D morphology between normal and developmentally dysplastic hips and to identify specific areas of undercoverage in children with DDH compared to age- and sex-matched controls.

Subjects were included if they were typically developing children with no other underlying conditions affecting their musculoskeletal system and had an available pelvic CT scan (67 hips). Custom software was used to measure standard variables defining acetabular morphology (version, tilt, surface area). Acetabuli were divided into equal octants; coverage angles were measured for each octant of interest. Variables were compared with age- and sex-matched controls (128 hips) using analysis of variance or the Mann-Whitney test.

Hips with DDH were more anteverted compared to normal hips (DDH: 22.6˚, Control: 16.4˚, p < 0.001). The surface area was similar between groups. 28% of hips had a global deficiency, 24% were anteriorly deficient, 19% were laterally deficient, 10% were anteverted (under covered anteriorly and over covered posteriorly), 3% were posteriorly deficient, and 15% of hips had borderline undercoverage. None of the hips in this cohort were found to be retroverted.

This is the first study to quantify the 3D acetabular deficiency in children with DDH compared to age- and sex-matched controls. We found wide variability in coverage patterns among dysplastic hips. It is imperative to define the specific acetabular deficiency for each individual patient prior to surgical correction.

III - Case-control study.

Patients with developmental dysplasia of the hip (DDH) may require a pelvic osteotomy to treat acetabular dysplasia. The Pemberton osteotomy and modified San Diego acetabuloplasty are two options available when surgically treating DDH. The purpose of this study was to compare outcomes following the Pemberton and modified San Diego when treating patients with acetabular dysplasia in typical DDH.

We included 45 hips in the modified San Diego group and 38 hips in the Pemberton group. Hips with less than two years follow-up and patients with a neuromuscular diagnosis were excluded. Clinical outcomes were rated using the modified McKay criteria with radiographic outcomes graded using the Severin score. Avascular necrosis (AVN) was assessed using the Kalamchi and MacEwen criteria.

Mean follow-up was 4.9 years (2.1 to 11.2). Both procedures produced similar decreases in the acetabular index (modified San Diego: 17.0˚ versus Pemberton: 15.2˚; p = 0.846). Most hips had good/excellent results using the modified McKay criteria (modified San Diego: 78%, Pemberton: 94%; p = 0.055). Most hips were rated as good/excellent on the Severin scale (modified San Diego: 100%, Pemberton: 97%, p = 0.485). The proportion of hips with AVN grade 2 or higher were similar between groups (modified San Diego: 0%, Pemberton: 3%; p = 0.458).

The modified San Diego acetabuloplasty is a safe and effective alternative to treat acetabular dysplasia in patients with typical DDH. By maintaining an intact medial cortex, acetabular reshaping can be customized to address each patient's specific acetabular deficiency.

Level III retrospective comparison.

Children with developmental dysplasia of the hip may require a pelvic osteotomy to treat acetabular dysplasia. Three osteotomies are commonly performed in these patients (Pemberton, Dega, and San Diego), though comparative studies of each are limited. The purpose of this study was to compare changes in acetabular morphology (acetabular version, volume, and octant coverage angles) created by these 3 osteotomies using matched patient-specific 3D-printed pelvic models.

Fourteen patients with developmental dysplasia of the hip and preoperative computed tomography (CT) imaging were retrospectively included. For each patient CT, bone and cartilage tissues were independently segmented, and 3 identical pelvises were 3D-printed using a dual material printer. Bone was printed with rigid material and cartilage with flexible material to simulate the flexibility of the triradiate cartilage and pubic symphysis. Pemberton, Dega, and San Diego acetabular osteotomies were performed on the triplicate set of 3D prints. Acetabular version, volume, and octant coverage angles (posterior, superior-posterior, superior, superior-anterior, and anterior) were determined before and after each mock surgery by morphologic assessment using preoperative and postoperative CT images.

San Diego osteotomy yielded a small increase (+3.34±1.71 degrees) in version, compared with decreases with Pemberton (-5.47±1.54 degrees) and Dega (-8.57±1.21 degrees, P<0.05). Acetabular volume decreased similarly for Pemberton (-13.36%±2.88%), Dega (-19.21%±2.73%), and San Diego (-19.29%±2.44%; P=0.215) osteotomies. San Diego osteotomy tended to have a larger postoperative increase in the posterior regions, and the Dega and Pemberton osteotomies tended to have larger postoperative increases in the anterior coverage regions.

Quantifiable differences were identified in acetabular octant coverage angles and version between the 3 pelvic osteotomies. San Diego osteotomy increased acetabular coverage posteriorly resulting in acetabular anteversion, whereas Pemberton and Dega had greater superior-anterior coverage resulting in relative acetabular retroversion. This study is the first known to utilize 3D-printed models for comparison of surgical approaches in pediatric pelvic osteotomies.

There is no consensus about the duration of post-operative immobilization in the treatment of DDH (developmental dysplasia of hip). Our aim in this study is to compare between two post-operative immobilization protocols for patients undergoing open reduction.

Thirty-eight hips in 32 patients assigned to group A were immobilized in hip spica for four weeks followed by abduction brace application which was gradually weaned through the periods of several months and 29 hips in 24 patients assigned to group B immobilized in hip spica for 12 weeks without further bracing. Both groups were surgically reduced using anterior approach between the ages of 12-24 months.

There were non-significant statistical difference between both groups as regards clinical and radiological outcome but there is significant statistical difference as regards AVN (avascular necrosis) on follow-up between both groups. The rate of AVN cannot be related to the method of immobilization, as there are many factors can lead to AVN of the hip as immobilization in an extreme position and tight reduction.

Group A post-operative immobilization protocol is safer and associated with less complications and more comfortable to the patient and parents than that used in group B. Early removal of hip spica cast and application of hip abduction brace does not increase the rate of re-dislocation.

Level III Retrospective comparative study.

Acetabular rim fractures, or os acetabuli, are hypothesized to occur as a result of an unfused ossification center or a stress fracture from repetitive impingement of an abnormally shaped femoral neck against the acetabular rim. When treated surgically, these fragments are typically excised as part of the correction for femoroacetabular impingement. However, in some patients, removal of these fragments can create symptoms of gross instability or microinstability of the hip. In these cases, internal fixation of the fragment is necessary. The purpose of this technical note is to describe indications, the arthroscopic technique, and postoperative care for fixation of acetabular rim fractures.

PemberSal osteotomy to improve femoral head coverage by rotating the acetabular roof ventrally and laterally.

Insufficient coverage of the femoral head, and can be combined with other surgical procedures such as femoral intertrochanteric varus-derotation osteotomy and open reduction for developmental dysplasia and dislocation of the hip or to improve sphericity and containment in Legg-Calvé-Perthes disease. This specific acetabuloplasty can only be performed in patients with an open epiphyseal growth-plate.

Increased bleeding tendency (e.g., inherited or iatrogenic); elevated anesthetic risk such as in cerebral palsy, arthrogryposis multiplex congenital, trisomies; syndromes require explicit interdisciplinary clarification to reduce perioperative risks; infections as in other elective surgeries; diseases/deformities making postoperative spica casting impossible or impractical (e.g., deformities of spinal cord or urogenital system, hernias requiring treatment); closed epiphyseal plate requires complex three-dimensional corrections of the acetabular roof (e.g., triple/periacetabular osteotomy).

Osteotomy from the iliac bone to the posterior ilioischial arm of the epiphyseal growth-plate cartilage; controlled fracture of the cancellous bone without breaking the medial cortex of the iliac bone for ventrocaudal rotation of the acetabular roof. To refill and stabilize the osteotomy site, an allogenic bone-wedge is interponated and secured by a resorbable screw or kirschner wire. This method also allows more complex reconstructions of the acetabular roof, e.g., by including the pseudo-cup in a modified Rejholec technique.

A spica cast is applied to immobilize the hip for 6 weeks. Afterwards physiotherapy can be performed under weight-bearing as tolerated. Radiographic check-ups every 6 months.

The risk of avascular necrosis of the femoral head (AVN) after treatment of developmental dysplasia of the hip is associated with the method of reduction. Some authors have suggested that open reduction is a risk factor for AVN; however, this is controversial. To our knowledge, a quantitative comparison of the incidence of AVN between closed and open reduction has not been conducted.

Published studies were identified by searching PubMed, EMBASE, and the Cochrane Library up to May, 2015, focusing on the incidence of AVN after closed or open reduction for developmental dysplasia of the hip in children aged <3 years. Patients were age-matched who were treated by either closed or open reduction, but without pelvic or femoral osteotomy. Two authors independently assessed eligibility and abstracted data. Discrepancies were discussed and resolved by consensus. We pooled the odds ratios (ORs) and 95% confidence intervals (95%CIs) from individual studies using a random-effects model and evaluated heterogeneity and publication bias.

Nine retrospective studies were included in this analysis. The pooled OR for comparing open reduction with closed reduction for all grades of AVN was 2.26 (95%CI = 1.21-4.22), with moderate heterogeneity (I = 44.7%, P = 0.107). The pooled OR for grades II to IV AVN was 2.46 (95%CI = 0.93-6.51), with high heterogeneity (I = 69.6%, P = 0.003). A significant association was also found for the further surgery between open and closed reduction, with a pooled OR of 0.30 (95%CI = 0.15-0.60) and moderate heterogeneity (I = 46.4%, P = 0.133). No evidence of publication bias or significant heterogeneity between subgroups was detected by meta-regression analyses.

Findings from this meta-analysis suggest that open reduction is a risk factor for the development of AVN compared with closed treatment. Future studies are warranted to investigate how open reduction combined with pelvis and/or femoral osteotomy affects the incidence of AVN.

Congenital hip dysplasia and hip dislocation are relatively common pathological conditions of the musculoskeletal system in infants. An early and certain diagnosis can now be achieved by sonographic hip screening within the framework of screening examination programs. This early diagnostic procedure in infants is essential particularly for a conservative treatment strategy. Therefore, apart from possessing in-depth knowledge, training of the examiner in specialist courses is of central importance. This article presents an overview of the entity of congenital hip dysplasia and hip dislocation, the diagnostics and treatment with special emphasis on recent developments.

Treatment is easier and complications are less likely to occur if developmental dysplasia of the hip (DDH) is diagnosed early. In this study, we examined the early results of open reduction using a medial approach which we had modified for DDH and analyzed the success of this technique and the associated complication rates, with a focus on avascular necrosis (AVN).

This is an Institutional Review Board-approved retrospective review of all patients diagnosed with DDH and treated with a modified medial approach at a single institution from July 1999 to December 2010. The patients' charts were analyzed for clinical and radiographic features.

Fifty-five hips of 41 patients, all of whom were treated by open reduction using a modified medial approach due to DDH, were evaluated retrospectively. The mean age of the patients at surgery was 19 (range 11-28) months, and the average follow-up was 5.5 (range 3-9.5) years. AVN was the most important complication in terms of radiological outcomes as assessed according to the Kalamchi-McEwen classification. Radiologic results were excellent or good in 51 hips (92.7 %) and fair-plus in four (7.3 %). Type 1 temporary AVN was detected in only two hips (3.6 %), and the lesions had disappeared completely in the final control graphs of these two patients. A secondary intervention was needed for two hips (3.6 %) of the same patients who were operated on due to bilateral DDH. No other complications, such as infection, re-dislocation, or subluxation, were seen in the operated patients.

We believe that treatment for DDH using a modified medial approach during early childhood is an effective and reliable method with low AVN rates. As shown here, this method achieves great success in radiological and clinical outcomes after a minimum 3-year follow-up.

The severity of avascular necrosis (AVN) after closed reduction of developmental dysplasia of the hip determines the final clinical outcomes. Our study aimed to correlate the possible predictors with the severity of AVN. After follow-up of the patients on skeletal maturity, 37 patients (39 hips) were included. Age at reduction is important to predict the severity of AVN. Older patients are at a greater risk of suffering from more severe AVN. Other values such as the degree of initial dislocation or the impact of the femoral head ossific nucleus show no precognition to the severity of AVN.

Steel's triple innominate osteotomy was created for correcting dysplastic acetabulum in adolescents and young adults. We modified Steel's triple innominate osteotomy with two anterior incisions and ramus cuts close to the acetabulum to improve the mobility of the fragment for better coverage of the hip. The purpose of this study was to compare these two techniques with respect to acetabular morphology, femoral head coverage, and medialization. From 1989 to 2007, 22 hips from 19 adolescents and young adults underwent triple innominate osteotomy for symptomatic acetabular dysplasia with Tonnis grades 1 or 2. We divided patients into group A (11 hips from 10 patients), comprising patients who underwent classical Steel's osteotomy, and group B (11 hips from nine patients), comprising patients who underwent modified Steel's osteotomy, with a minimum follow-up of 2 years. Preoperative and postoperative radiographs of pelvis in the standing position were available for comparison. We used Sharp's angle, center-edge angle, femoral head extrusion index, and center-head distance discrepancy to evaluate hip morphology, femoral head coverage, and medialization, respectively. The paired t-test was used for statistical calculation with P-value less than 0.05 considered significant. The postoperative Sharp's angle, center-edge angle, femoral head extrusion index, and center-head distance discrepancy all had better results in group B with statistical significance. Other variants such as age, sex, and operation side did not have any significance. No postoperative complication was encountered. Our modified technique provided a better mobility of the rotated fragment in correcting acetabular dysplasia with a short learning curve. Most importantly, we provided greater coverage and medialization of the femoral head for better long-term results.

level III, retrospective comparative study.

To study the radiographic projected hip parameters of the proximal femur and acetabulum in young and adult Estrela Mountain Dogs with normal and abnormal hip joints. The parameters evaluated were: femoral angles of inclination and anteversion (FAI and FAA), femoral neck length and width (FNL and FNW), acetabular depth (AD) and acetabular angle of retrotorsion (AAR).

Five hundred and twenty-five standard hip-extended ventrodorsal radiographic views and 622 mediolateral views of the right and left femur were used to measure the FAI, FAA, FNL, FNW, AD, AAR and modified AAR (mAAR).

The FAI decreased in adult dysplastic dogs, in females and in right femora; FAA decreased with age; FNL was characterized by a greater relative size in normal adult animals; FNW was greater in abnormal hips in young and adult animals; AD was less in adult dysplastic dogs and in right hips; AAR was similar in the studied groups; mAAR was greater in abnormal hips and in left hips.

The data may be used in future studies, which compare this breed to others. Morphological variations in femoral neck and acetabular morphometric parameters were present, and these variables in dogs with different ages and with hips in varying states of health should not be compared.

Microinstability and ligament teres lesions are emergent topics on the hip pathology. These entities are an increasingly recognized cause of persistent hip pain and should be considered in the differential diagnosis of the patient with hip pain. Conventional (non-arthrographic) CT and MR have a very limited role in the evaluation of these entities. CTa and MRa have emerged as the modalities of choice for pre-operative imaging of ligamentum teres injuries and microinstability. To date, pre-operative imaging detection of these pathologies is not widespread but with appropriate imaging and a high index of suspicion, preoperative detection should improve. This article discusses current concepts regarding anatomy, biomechanics, clinical findings, diagnosis and treatment of ligament teres lesions and microinstability.

Chronic mechanical overload of the acetabular rim may lead to acetabular labral disease in patients with hip dysplasia. Although arthroscopic debridement of the labrum may provide symptomatic relief, the underlying mechanical abnormality remains. There is little information regarding how the results of periacetabular osteotomy are affected by a prior primary treatment for labral disease in the presence of acetabular dysplasia.

In a retrospective matched-cohort study, seventeen patients who had arthroscopic labral debridement prior to periacetabular osteotomy (the arthroscopy group) were compared with a control group of thirty-four patients who did not undergo arthroscopic labral debridement prior to periacetabular osteotomy (the non-arthroscopy group). Two control patients were randomly matched to each experimental patient from a pool of controls. Functional outcomes were assessed with use of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Failure of periacetabular osteotomy was defined as conversion to a total hip replacement.

Changes in the preoperative and postoperative WOMAC scores of arthroscopy and non-arthroscopy patients were comparable, and the differences between the two treatment groups were not significant. We were unable to show a significant difference between the seventeen arthroscopy and thirty-four non-arthroscopy patients with regard to the risk of having to undergo a total hip replacement.

When arthroscopic labral debridement fails to improve symptoms in patients with labral disease secondary to acetabular dysplasia, periacetabular osteotomy may still be considered as a joint-preserving procedure that can achieve good functional results.

Developmental dysplasia of the hip predisposes to premature degenerative hip disease. A number of operations have been described to improve acetabular cover and have achieved varying degrees of success. We present the case of an 84-year-old woman, who underwent a shelf procedure to reconstruct a dysplastic hip 75 years ago. To date, the shelf remains intact and the hip is asymptomatic. We believe this represents the longest documented outcome of any procedure to stabilise the hip.

Untreated hip dysplasia can result in a degenerative process joint and secondary osteoarthritis at an early age. While most periacetabular osteotomies (PAOs) are performed to relieve symptoms, the osteotomy is presumed to slow or prevent degeneration unless irreparable damage to the cartilage has already occurred.

We therefore determined (1) whether changes in the thickness of the cartilage in the hip occur after PAO, and (2) how many patients had an acetabular labral tear and whether labral tears are associated with thinning of the cartilage after PAO.

We prospectively followed 22 women and four men with hip dysplasia with MRI before PAO and again 1 year and 2(1/2) years postoperatively to determine if cartilage thinning (reflecting osteoarthritis) occurred. The thickness of the femoral and acetabular cartilage was estimated with a stereologic method. Three and one-half years postoperatively, 18 of 26 patients underwent MR arthrography to investigate if they had a torn acetabular labrum.

The acetabular cartilage thickness differed between 1 and 2(1/2) years postoperatively (preoperative 1.40 mm, 1 year postoperatively 1.47 mm, and 2(1/2) years postoperatively 1.35 mm), but was similar at all times for the femoral cartilage (preoperative 1.38 mm, 1 year postoperatively 1.43 mm, and 2(1/2) years postoperatively 1.38 mm.) Seventeen of 18 patients had a torn labrum. The tears were located mainly superior on the acetabular rim.

Cartilage thickness 2(1/2) years after surgery compared with preoperatively was unchanged indicating the osteoarthritis had not progressed during short-term followup after PAO.

To treat neglected developmental dysplasia of the hip (DDH), we performed Salter innominate osteotomy with a modification of transiliac lengthening. We asked whether this modified technique caused posterior coverage problems and triradiate cartilage injury.

We retrospectively reviewed 45 patients with unilateral DDH treated by open reduction and femoral shortening and modified Salter innominate osteotomy. The age at operation was 38.44 +/- 19.79 months (mean +/- standard deviation). Minimum follow-up was 24 months (mean +/- standard deviation 49.84 +/- 27.73 months; range 24-112 months). We measured the tilt of the iliac bone (difference of preoperative and postoperative acetabular index values). We divided the hips into two groups. There were 29 hips in Group 1 (deviation amount <20 degrees ) and 16 hips in Group 2 (deviation amount > or =20 degrees ). At the latest follow-up, frontal and axial plane computed tomographic analyses were performed. We measured medial wall thickness, teardrop width, and hemipelvis heights to evaluate triradiate cartilage intactness indirectly. Posterior center edge angle, which reflects posterior coverage of the hip, was also measured.

We found no differences between groups regarding all measured parameters.

Modified Salter osteotomy with transiliac lengthening can be performed safely in the treatment of neglected DDH.

Despite expensive screening and breeding programmes, hip dysplasia (HD) continues to be one of the most common orthopaedic diseases in dogs. The vast majority of dogs afflicted with HD show minimal to no clinical signs, but it can also be a highly debilitating condition for both working and pet dogs. Hip joint laxity is considered a major risk factor for the development of degenerative joint disease and a definitive diagnosis is made if characteristic signs are evident on a ventrodorsal view of the pelvis. Early prediction of the condition can be made using stress radiographic techniques to evaluate the passive hip laxity. The diagnosis of HD may be used for the purpose of selecting breeding stock or to decide on the best treatment approach. Breeding programmes based on individual dog phenotypes have been ineffective and a selection procedure based on breeding value (BV) estimation is recommended. Traditional conservative and surgical treatment approaches are reserved for dogs with overt clinical signs of the disease but such treatments can be expensive and aggressive, and are often ineffective in eliminating clinical signs or subluxation and in preventing the development of degenerative joint disease. The implementation of breeding programmes based on BVs and further research into early prediction/diagnosis of HD and effective preventive treatment approaches are essential.

Assessment of the natural history of developmental dysplasia of the hip (DDH) is indispensable for age-dependent treatment of these patients. Based on a systematic meta-analysis of the published literature, this study gives an overview of the spontaneous course of DDH in different age decades. Furthermore, these results are discussed in the context of physiologic development of the hip. The data were compiled by a systematic literature search of medical databases from 1975 through 2007. For this evaluation, only papers that presented as high a level of evidence as possible were included. In early childhood, DDH with subluxation or dislocation necessitates treatment; otherwise, the spontaneous course leads invariably to osteoarthritis of the hip. However, a stable, well-centered dysplastic hip has a high potential of developing as a physiologic joint. In the analyzed data, an association between mild or moderate DDH after the end of growth and the development of osteoarthritis could not be demonstrated. The level of evidence of existing data is not sufficient to determine that persisting mild dysplasia is a relevant ethiopathological factor for osteoarthrosis of the hip. Therefore, prospective epidemiological studies are required.

The typical dysplastic hip joint is characterised by maldirection of the acetabulum and femoral neck, insufficient coverage of the femoral head focally and globally and erosions of the limbus acetabuli (1). An unknown number of persons with hip dysplasia will suffer from pain in hip or groin, decreased hip function and development of osteoarthritis at a young age. The Bernese periacetabular osteotomy is performed to prevent osteoarthritis in patients with hip dysplasia and has been carried out at Aarhus University Hospital, Denmark since 1996 with more than 500 osteotomies performed. Throughout the years, research and quality improvement of the treatment has taken place and this PhD thesis is part of that process. The aims of this PhD thesis were to evaluate outcome aspects after periacetabular osteotomy in terms of I) estimating the projected loadbearing surface before and after periacetabular osteotomy, II) estimating bone density changes in the acetabulum after periacetabular osteotomy, III) developing a technique to precisely and efficiently estimate the thickness of the articular cartilage in the hip joint and IV) examining the stability of the re-orientated acetabulum after periacetabular osteotomy. In study I, we applied a stereologic method based on 3D computed tomography (CT) to estimate the projected loadbearing surface in six normal hip joints and in six dysplastic hips. The dysplastic hips were CT scanned before and after periacetabular osteotomy. We found that the average area of the projected loadbearing surface of the femoral head preoperatively was 7.4 (range 6.5-8.4) cm2 and postoperatively 11 (9.8-14.3) cm2. The area of the projected loadbearing surface was increased significantly with a mean of 49% (34-70%) postoperatively and thus comparable with the load-bearing surface in the normal control group. Double measurements were performed and the error variance of the mean was estimated to be 1.6%. The effect of overprojection, on the projected loadbearing surface was minimal. Consequently, the stereo-logic method proved to be precise and unbiased. The study indicates that this method is applicable in monitoring the loadbearing area in the hip joint of patients undergoing periacetabular osteotomy. In study II, a method based on CT and 3D design-based sampling principles was used to estimate bone density in different regions of the acetabulum. Baseline density was measured within the first seven days following periacetabular osteotomy and compared with density two years postoperatively. Double measurements were performed on three patients, and the error variance was estimated to be 0.05. Six patients with hip dysplasia scheduled for periacetabular osteotomy were consecutively included in the study. Bone density increased significantly in the anteromedial quadrant of the acetabulum as well as in the posteromedial quadrant between the two time-points. In the anterolateral quadrant bone density was unchanged following surgery, and the same was true for the posterolateral quadrant. We suggest that the observed increase in bone density medially represents a remodelling response to an altered load distribution after periacetabular osteotomy. The described method is a precise tool to estimate bone density changes in the acetabulum. Study III. As periacetabular osteotomy is performed on dysplastic hips to prevent osteoarthritic progression, changes in the thickness of the articular cartilage is a central variable to follow over time. 26 dysplastic hips on 22 females and 4 males were magnetic resonance imaged (MRI) preoperatively. The first 13 patients were examined twice, with complete repositioning of the patient and set-up in order to obtain an estimate of the precision of the method used. To show the acetabular and femoral cartilages separately, an ankle traction device was used during MRI. This device pulled the leg distally with a load of 10 kg. The mean thickness of the acetabular cartilage was 1.26 mm, SD 0.04 mm. The mean thickness of the femoral cartilage was 1.18 mm, SD 0.06. The precision calculated as the error variance was estimated for the thickness of the acetabular cartilage to 0.01 and femoral cartilage 0.02. We suggest that the method can be advantageous for assessing the progression of osteoarthritis in dysplastic hips after periacetabular osteotomy. In study IV, 32 dysplastic hips, 27 females and 5 males were included in the study. Radiostereometric examinations (RSA) were done at one week, four weeks, eight weeks and six months. Data are presented as mean + SD. Six months postoperatively, the acetabular fragment had migrated 0.7 mm + 0.8 medially, and 0.7 mm + 0.5 proximally. Mean rotation in adduction was 0.5 degrees + 1.3. In other directions, mean migration was below 0.5 mm/degrees. There was no statistical difference between migration 8 weeks and 24 weeks postoperatively in translation or rotation. Due to the limited migration, we find our postoperative partial weight-bearing regime safe. In conclusion, the studies in the present PhD thesis indicate that the projected loadbearing area of the hip joint increases considerable in patients undergoing periacetabular osteotomy and a method to estimate this area was described. Bone density increases in the medial quadrants two years postoperative and a method is developed to precisely estimate bone density on CT images. Also a method to precisely estimate cartilage thickness was presented and we suggest that the method can be advantageous for assessing the progression of osteoarthritis in dysplastic hips after periacetabular osteotomy. Due to the very limited migration of the acetabular fragment fixated with two screws, we find our fixation sufficient and the postoperative partial weight-bearing regimen safe.

The purpose of this study was to compare the biomechanical stability of triple innominate osteotomies fixed with either bioabsorbable or stainless steel screws. Triple innominate osteotomies were performed on composite hemipelves and fixed with either three 4.5-mm bioabsorbable screws or three stainless steel 4.5-mm screws. Two screws were placed from the iliac wing into the acetabular fragment, and 1 screw was placed from below the acetabular fragment into the iliac wing. Eight specimens for each screw type were biomechanically tested in an anatomical position (replicating weight bearing) and in a flexed and abducted position (replicating spica cast positioning). Specimens were cyclically loaded between 10 and 450 N to simulate the hip contact force in this population. Lower screws were then removed, and specimens were tested under identical conditions. Fragment displacement (mm) and construct stiffness (N/mm) were compared with a 2-way analysis of variance (P < 0.05). There were no significant differences between materials for fragment displacement or construct stiffness. Anatomical position showed significantly less displacement than spica position for both materials. Initial displacement in the spica position was significantly less during lower loads for stainless steel fixation. Bioabsorbable screws demonstrate comparable biomechanical stability to stainless steel screws in anatomical and spica positions at physiological loads. Flexion and abduction of the femur adversely affect the stability of the construct for both materials. Bioabsorbable screws behave similarly to steel screws when stabilizing triple innominate osteotomies and would have the advantage of not requiring a second surgery for screw removal. Confirmation of biocompatibility should be completed before widespread clinical application.

Intermediate-term immobilization may lead to an increase in serum and urinary calcium. In order to test this hypothesis, we evaluated 46 children, 21 with Legg-Calvé-Perthes disease (LCP; 7.2+/-1.8 years old) and 25 with developmental dysplasia of the hip joint (DDH; 10+/-5 months of age), submitted to immobilization for up to 16 weeks. These two conditions require intermediate-term immobilization as treatment modality, and no studies evaluating calcium metabolism in these groups of patients have been conducted. In LCP patients, blood and 24-h urine samples were obtained before the beginning of treatment and after 1, 6, 8, 14 and 16 weeks of immobilization, while in DDH patients, blood and spot urine samples were collected before treatment and after 6 and 14 weeks of treatment. Urinary calcium, creatinine, potassium and sodium as well as serum calcium, phosphorus, parathyroid hormone, creatinine and alkaline phosphatase were determined in those samples. Renal ultrasound was performed before and after treatment. A mean increase of 2.3 times baseline values of urinary calcium was observed in 40% of previously normocalciuric LCP patients after only 1 week of immobilization. Among the DDH children, who had never previously ambulated, there was no significant variation in the urinary calcium excretion. None of the serum parameters changed in either group throughout the study. Urinary stones were not evidenced by renal ultrasound. Therefore, the present data suggested that intermediate-term immobilization led to a transient increase in urinary calcium in 40% of LCP patients. Complications such as urinary stones were not observed. In conclusion, this modality of treatment does not impose an increased risk of urinary stone formation in LCP and DDH patients.

To investigate and compare delayed gadolinium (Gd-DTPA)-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) in the hip joint using intravenous (i.v.) or ultrasound-guided intra-articular (i.a.) Gd-DTPA injection.

In 10 patients (50% males, mean age 58 years) with clinical and radiographic hip osteoarthritis (OA; Kellgren score II-III), MRI of the hip was performed twice on a clinical 1.5T MR scanner: On day 1, before and 90-180 min after 0.3 mmol/kg body weight i.v. Gd-DTPA and, on day 8, 90-180 min after ultrasound-guided i.a. injection of a 4 mmol/l Gd-DTPA solution. Coronal STIR, coronal T1 fat-saturated spin-echo, and a cartilage-sensitive gradient-echo sequence (3D T1 SPGR) in the sagittal plane were applied. RESULTS Both the post-i.v. and post-i.a. Gd-DTPA images showed significantly higher signal-to-noise (SNR) and contrast-to-noise (CNR) in the joint cartilage compared to the non-enhanced images (P < 0.002). I.a. Gd-DTPA provided significantly higher SNR and CNR compared to i.v. Gd-DTPA (P < 0.01). Furthermore, a better delineation of the cartilage in the synovial/cartilage zone and of the chondral/subchondral border was observed.

The dGEMRIC MRI method markedly improved delineation of hip joint cartilage compared to non-enhanced MRI. The i.a. Gd-DTPA provided the best cartilage delineation. dGEMRIC is a clinically applicable MRI method that may improve identification of early subtle cartilage damage and the accuracy of volume measurements of hip joint cartilage.

Although relatively uncommon compared with the shoulder, hip instability can be a source of significant disability and is a commonly unrecognized injury. Hip instability can be traumatic or atraumatic in origin. Our understanding and treatment plan for hip instability due to traumatic events is well established. However, our understanding and treatment modalities for hip instability due to atraumatic events or repetitive motion in high level athletes are not as well defined. In this article, we will review the spectrum of traumatic and atraumatic hip instability and discuss the relevant anatomy, history, and physical examination findings, imaging studies, and treatment options with a focus on hip arthroscopy, and review of the literature.