[Treatment strategies for the combination of hip dysplasia, femoroacetabular impingement and malrotation of the proximal femur : How much should be corrected?] / Therapieentscheidung bei Kombinationspathologien Dysplasie ­ FAI ­ Fehlrotation : Wann und wieviel sollte korrigiert werden?

BACKGROUND: Hip dysplasia, FAI and femoral malrotation often occur together, resulting in mixed symptoms and severe biomechanical limitations of the hip. OBJECTIVES: To report on the current recommendations for the best possible diagnosis and treatment strategies of combination pathologies in hip-preserving surgery. METHODS: Review and discussion of the relevant literature with consideration of own experience in the treatment of complex combined pathomorphologies of the hip. RESULTS: Patient history and a thorough clinical examination are key for determining the predominant pathomorphologies causing the symptoms. Standardized conventional ap pelvic and axial images of the hip are the basis for the radiological assessment of the hip, supplemented with MRI, CT and animations of the hip, depending on the case. As the pathologies influence each other functionally, a stepwise approach to treatment is recommended. The functionally most relevant pathology is treated first, followed by further corrections as needed. The primary goal is to achieve a stable hip with normal acetabular coverage, followed by an impingement-free range of motion and normalized musculoskeletal function. Care must be taken in the choice of surgical method to ensure that all pathologies can be adequately treated. CONCLUSION: Complex, combined pathologies of the hip can be treated sufficiently with hip-preserving surgery. A thorough diagnosis is important in order to recognize the functional interaction of the different pathologies. The goal of the surgical therapy is a correctly covered, stable hip with a normal range of motion.

Surgical hip dislocation with relative femoral neck lengthening and retinacular soft-tissue flap for sequela of Legg-Calve-Perthes disease.

OBJECTIVE: Correction of post-LCP (Legg-Calve-Perthes) morphology using surgical hip dislocation with retinacular flap and relative femoral neck lengthening for impingent correction reduces the risk of early arthritis and improves the survival of the native hip joint. INDICATIONS: Typical post-LCP deformity with external and internal hip impingement due to aspherical enlarged femoral head and shortened femoral neck with high riding trochanter major without advanced osteoarthritis (Tönnis classification ≤ 1) in the younger patient (age < 50 years). CONTRAINDICATIONS: Advanced global osteoarthritis (Tönnis classification ≥ 2). SURGICAL TECHNIQUE: By performing surgical hip dislocation, full access to the hip joint is gained which allows intra-articular corrections like cartilage and labral repair. Relative femoral neck lengthening involves osteotomy and distalization of the greater trochanter with reduction of the base of the femoral neck, while maintaining vascular perfusion of the femoral head by creation of a retinacular soft-tissue flap. POSTOPERATIVE MANAGEMENT: Immediate postoperative mobilization on a passive motion device to prevent capsular adhesions. Patients mobilized with partial weight bearing of 15 kg with the use of crutches for at least 8 weeks. RESULTS: In all, 81 hips with symptomatic deformity of the femoral head after healed LCP disease were treated with surgical hip dislocation and offset correction between 1997 and 2020. The mean age at operation was 23 years; mean follow-up was 9 years; 11 hips were converted to total hip arthroplasty and 1 patient died 1 year after the operation. The other 67 hips showed no or minor progression of arthrosis. Complications were 2 subluxations due to instability and 1 pseudarthrosis of the lesser trochanter; no hip developed avascular necrosis.

Good Outcome Scores and Low Conversion Rate to THA 10 Years After Hip Arthroscopy for the Treatment of Femoroacetabular Impingement.

BACKGROUND: Arthroscopic treatment of symptomatic femoroacetabular impingement (FAI) has promising short-term to mid-term results. In addition to treating acute pain or impaired function, the goal of hip-preserving surgery is to achieve a lasting improvement of hip function and to prevent the development of osteoarthritis. Long-term results are necessary to evaluate the effectiveness of surgical treatment and to further improve results by identifying factors associated with conversion to THA. QUESTIONS/PURPOSES: (1) How do the Merle d'Aubigné-Postel scores change from before surgery to follow-up of at least 10 years in patients undergoing hip arthroscopy for the treatment of FAI? (2) What is the cumulative 10-year survival rate of hips with the endpoints of conversion to THA or a Merle d'Aubigné-Postel score less than 15? (3) Which factors are associated with conversion to THA? METHODS: Between 2003 and 2008, we treated 63 patients (65 hips) for symptomatic FAI with hip arthroscopy at our institution. During that period, the indications for using arthroscopy were correction of anterior cam morphology and anterolateral rim trimming with debridement or reattachment of the labrum. We excluded patients who were younger than 16 years and those who had previous trauma or surgery of the hip. Based on that, 60 patients (62 hips) were eligible. A further 17% (10 of 60) of patients were excluded because the treatment was purely symptomatic without treatment of cam- and/or pincer-type morphology. Of the 50 patients (52 hips) included in the study, 2% (1) of patients were lost before the minimum study follow-up of 10 years, leaving 49 patients (51 hips) for analysis. The median (range) follow-up was 11 years (10 to 17). The median age at surgery was 33 years (16 to 63). Ninety percent (45 of 50) of patients were women. Of the 52 hips, 75% (39 of 52) underwent cam resection (femoral offset correction), 8% (4 of 52) underwent acetabular rim trimming, and 17% (9 of 52) had both procedures. Additionally, in 35% (18 of 52) of hips the labrum was debrided, in 31% (16 of 52) it was resected, and in 10% (5 of 52) of hips the labrum was reattached. The primary clinical outcome measurements were conversion to THA and the Merle d'Aubigné-Postel score. Kaplan-Meier survivorship and Cox regression analyses were performed with endpoints being conversion to THA or Merle d'Aubigné-Postel score less than 15 points. RESULTS: The clinical result at 10 years of follow-up was good. The median improvement of the Merle d'Aubigné-Postel score was 3 points (interquartile range 2 to 4), to a median score at last follow-up of 17 points (range 10 to 18). The cumulative 10-year survival rate was 92% (95% CI 85% to 99%) with the endpoints of conversion to THA or Merle d'Aubigné-Postel score less than 15. Factors associated with conversion to THA were each year of advancing age at the time of surgery (hazard ratio 1.1 [95% CI 1.0 to 1.3]; p = 0.01) and preoperative Tönnis Grade 1 compared with Tönnis Grade 0 (no sign of arthritis; HR 17 [95% CI 1.8 to 166]; p = 0.01). CONCLUSION: In this series, more than 90% of patients retained their native hips and reported good patient-reported outcome scores at least 10 years after arthroscopic treatment of symptomatic FAI. Younger patients fared better in this series, as did hips without signs of osteoarthritis. Future studies with prospective comparisons of treatment groups are needed to determine how best to treat complex impingement morphologies. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Improved Cartilage Quality on Delayed Gadolinium-Enhanced MRI of Hip Cartilage after Subchondral Drilling of Acetabular Cartilage Flaps in Femoroacetabular Impingement Surgery at Minimum 5-Year Follow-Up.

OBJECTIVE: To assess whether subchondral drilling of acetabular cartilage flaps during femoroacetabular impingement (FAI) surgery improves (1) acetabular dGEMRIC indices and (2) morphologic magnetic resonance imaging (MRI) scores, compared with hips in which no additional treatment of cartilage lesions had been performed; and (3) whether global dGEMRIC indices and MRI scores correlate. DESIGN: Prospective cohort study of consecutive patients with symptomatic FAI treated with open surgery between 2000 and 2007. Patients with subchondral drilling of acetabular cartilage flaps were allocated to the study group, those without drilling to the control group. All patients underwent indirect 3-T MR arthrography to assess cartilage quality by dGEMRIC indices and a semiquantitative morphologic MRI score at minimum 5 years after surgery. dGEMRIC indices and morphologic MRI scores were compared between and among groups using analysis of covariance/paired t tests. RESULTS: No significant difference was found between the global dGEMRIC indices of the study group (449 ± 147 ms, 95% CI 432-466 ms) and the control group (428 ± 143 ms, 95% CI 416-442 ms; P = 0.235). In regions with cartilage flaps, the study group showed higher dGEMRIC indices (472 ± 160 ms, 95% CI 433-510 ms) compared with the control group (390 ± 122 ms, 95% CI 367-413 ms; P < 0.001). No significant differences were found for the morphologic MRI scores. A strong inversely linear correlation between the dGEMRIC indices and the morphologic MRI scores (r = -0.727, P < 0.001) was observed. CONCLUSIONS: Treatment of acetabular cartilage flaps with subchondral drilling leads to better cartilage quality in regions with cartilage flaps at minimum 5 years of follow-up.

Subchondral drilling for chondral flaps reduces the risk of total hip arthroplasty in femoroacetabular impingement surgery at minimum five years follow-up.

INTRODUCTION:: The best treatment of acetabular chondral flaps during surgery for femoroacetabular impingement (FAI) is unknown. We asked if subchondral drilling improves clinical and radiographic outcome and if there are factors predicting failure. METHODS:: We treated 79 patients with symptomatic FAI and acetabular chondral flaps with surgical hip dislocation between January 2000 and December 2007. Exclusion of all patients with previous hip pathology or trauma resulted in 62 patients (80 hips). The chondral flap was slightly debrided in 43 patients/51 hips (control group). In 28 patients/29 hips (study group), additional osseous drilling was performed. 4 patients (5 hips, 6%) were lost to follow-up. Mean follow-up was 9 years (5-13 years). The groups did not differ in demographic data, radiographic parameters or follow-up. Clinical outcome was assessed with the Merle d'Aubigné score, modified Harris Hip Score and University of California Los Angeles activity score and progression of osteoarthritis with the Tönnis grade. RESULTS:: No patient underwent conversion to total hip arthroplasty (THA) in the drilling group compared to 7 patients (8 hips, 16%) in the control group ( p = 0.005); in the remaining hips, clinical scores and progression of Tönnis grade did not differ. Increased acetabular coverage, age and body mass index were univariate predictive factors for conversion to THA. No drilling was as an independent predictive factor for conversion to THA (hazard ratio 58.07, p = 0.009). CONCLUSION:: Subchondral drilling under acetabular chondral flaps during surgical treatment of FAI is an effective procedure to reduce the rate of conversion to THA.

Imaging appearance and distribution of intra-articular adhesions following open FAI surgery.

OBJECTIVES: To evaluate the appearance and distribution of intra-articular adhesions on direct MR arthrograms (MRA) in symptomatic patients after surgical hip dislocation (SHD) for the treatment of femoroacetabular impingement (FAI). METHODS: All 18 patients (19 hips) who underwent arthroscopic debridement for treatment of symptomatic adhesions after open surgery of FAI between 2003 and 2012 and that had a complete set of pre- and postoperative direct MRA were evaluated. On radial PD-w images, pre- and postoperative osseous alpha angles were measured. Signal intensity and degree of obliteration of the peripheral compartment of the hip joint were assessed circumferentially at each 'half-hour' position and quantified with the adhesion alpha angle (measured between a line connecting the most proximal appearance of adhesions on the femoral neck with the femoral head center and the femoral neck axis). Linear regression analysis was performed between the site of correction and adhesions. As a control group, all patients (9; 9 hips) that underwent revision surgery during the same time period in which adhesions were not the primary cause for revision were evaluated. RESULTS: Femoral adhesions primarily (47%) appeared as intermediate, complete obliterations correlating with the site of offset correction (R = 0.883, p < 0.001). Adhesion alpha angles were comparable to the pre-operative osseous alpha angles (21/24 positions, p > 0.05) and were greater than the postoperative osseous alpha angles (11/24 positions, p < 0.05). Most labral adhesions (83.2%) appeared as adjacent and correlated with the site of rim trimming (R = 0.777, p < 0.001). In the control group, the most common reason for revision surgery was persisting cam deformity (67%). The radiographic findings were confirmed intra-operatively. CONCLUSION: Intra-articular adhesions most commonly appear at the site of primary offset correction. Recurrent impingement due to scar tissue may be quantified with the adhesion alpha angle. MRA of the hip are suitable to distinguish between postoperative adhesions and other known causes for persisting symptoms.

Influence of evolution on cam deformity and its impact on biomechanics of the human hip joint.

Anatomy and biomechanics of the human hip joint are a consequence of the evolution of permanent bipedal gait. Habitat and behaviour have an impact on hip morphology and significant differences are present even within the same biological family. The forces acting upon the hip joint are mainly a function of gravitation and strength of the muscles. Acetabular and femoral anatomy ensure an inherently stable hip with a wide range of motion. The femoral head in first human ancestors with upright gait was spherical (coxa rotunda). Coxa rotunda is also seen in close human relatives (great apes) and remains the predominant anatomy of present-day humans. High impact sport during adolescence with open physis however can activate an underlying genetic predisposition for reinforcement of the femoral neck, causing an epiphyseal extension and the formation of an osseous asphericity at the antero-superior femoral neck (cam deformity). The morphology of cam deformity is similar to the aspherical hips of quadrupeds (coxa recta), with the difference that in quadrupeds the asphericity is posterior. It has been postulated that this is due to the fact that humans bear weight on the extended leg, while quadrupeds bear weight at 90-100° flexion. The asphericity alters the biomechanical properties of the joint and as it is forced into the acetabulum leading to secondary cartilage damage. It is considered a risk factor for later development of osteoarthritis of the hip. Clinically this presents as reduced range of motion, which can be an indicator for the structural deformity of the hip. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:XX-XX, 2018.

[Biologic Reconstruction of Full Sized Cartilage Defects of the Hip: A Guideline from the DGOU Group "Clinical Tissue Regeneration" and the Hip Committee of the AGA]. / Biologische Rekonstruktion lokalisiert vollschichtiger Knorpelschäden des Hüftgelenks: Empfehlungen der Arbeitsgemeinschaft "Klinische Geweberegeneration" der DGOU und des Hüftkomitees der AGA.

Background Symptomatic pre-arthritic deformities such as femoroacetabular impingement (FAI) or hip dysplasia often lead to localised cartilage defects and subsequently to osteoarthritis. The present review of the working group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Trauma (DGOU) and the hip committee of the AGA (German speaking Society for Arthroscopy and Joint Surgery) provides an overview of current knowledge of the diagnosis and surgical treatment of cartilage defects, in order to infer appropriate therapy recommendations for the hip. Methods Review of FAI and resultant cartilage damage in the hip as reported in published study findings in the literature and discussion of the advantages and disadvantages of different surgical procedures to preserve the joint. Results Most published studies on the surgical treatment of cartilage damage in the hip report defects caused by cam-type FAI at the acetabulum. Development of these defects can be prevented by timely elimination of the relevant deformities. At present, current full-thickness cartilage defects are mostly treated with bone marrow-stimulating techniques such as microfracture (MFx), with or without a biomaterial, and matrix-assisted autologous chondrocyte transplantation (MACT). Osteochondral autologous transplantation (OAT) is not the treatment of choice for isolated full-thickness chondral defects at the hip, because of the unfavourable risk-benefit profile. Due to the relatively short history of cartilage repair surgery on the hip, the studies available on these procedures have low levels of evidence. However, it is already becoming obvious that the experience gained with the same procedures on the knee can be applied to the hip as well. For example, limited healing and regeneration of chondral defects after MFx can also be observed at the hip joint. Conclusions The cartilage surface of the acetabulum, where FAI-related chondral lesions appear, is considerably smaller than the weight-bearing cartilage surface of the knee joint. However, as in the knee joint, MACT is the therapy of choice for full-thickness cartilage defects of more than 1.5 - 2 cm2. Minimally invasive types of MACT (e.g. injectable chondrocyte implants) should be preferred in the hip joint. In cases where a single-stage procedure is indicated or there are other compelling reasons for not performing a MACT, a bone marrow-stimulating technique in combination with a biomaterial covering is preferable to standard MFx. For treatment of lesions smaller than 1.5 - 2 cm2 the indication for a single-stage procedure is wider. As with defects in the knee, it is not possible to determine a definite upper age limit for joint-preserving surgery or MACT in the hip, as the chronological age of patients does not necessarily correlate with their biological age or the condition of their joints. Advanced osteoarthritis of the hip is a contraindication for any kind of hip-preserving surgery. Long-term observations and prospective randomised studies like those carried out for other joints are necessary.

What Are the Risk Factors for Revision Surgery After Hip Arthroscopy for Femoroacetabular Impingement at 7-year Followup?

BACKGROUND: In recent years, surgical treatment of symptomatic femoroacetabular impingement (FAI) has been increasingly performed using arthroscopy. Bony pathomorphologies and damage to the labrum as well as cartilage defects can be addressed with comparable results to open surgery with overall less surgery-related complications. Despite the increasing importance of hip arthroscopy, however, reports on midterm clinical and radiographic outcomes and comparison to open surgical hip dislocation are scarce. QUESTIONS/PURPOSES: (1) What are the clinical and radiographic outcomes at a mean 7-year followup; (2) what is the cumulative 7-year survivorship, using the endpoints of THA, progression of osteoarthritis according to Tönnis, or poor clinical outcome with a Merle d'Aubigné score of less than 15 points, of hips with symptomatic FAI treated arthroscopically; and (3) what factors were associated with revision surgery? METHODS: Between 2003 and 2008 we performed a total of 62 arthroscopic procedures (60 patients) for FAI. For the same indication, we also performed 571 surgical hip dislocations during that time. Standardized treatment was femoral offset correction, acetabular rim trimming, or both and treatment of labral or chondral defects. An arthroscopic approach was generally used if the pathomorphology was located in the anterosuperior quadrant of the hip and was gradually used for more complex cases. We excluded 10 hips (10 patients) in which the standardized treatment was not achieved and no offset correction or acetabular rim trimming was performed. Of the remaining 52 hips (50 patients), 39 hips underwent isolated femoral offset correction, four hips isolated acetabular rim trimming, and nine hips both procedures. At a mean followup of 7 years (range, 5-11 years), the Merle d'Aubigné clinical score was obtained and plain radiographs were examined (Tönnis grade, heterotopic ossification, lateral center-edge [LCE] angle, acetabular index [AI], extrusion index, alpha angle, and pistol grip deformity). Cumulative survivorship was calculated according to Kaplan-Meier using conversion to THA, progression of osteoarthritis (one or more Tönnis grades), or poor clinical outcome (Merle d'Aubigné score < 15 points) as endpoints. Cox regression analysis was used to identify univariate factors associated with revision surgery. RESULTS: At last followup we detected a significant but possibly not clinically relevant increase in Merle d'Aubigné scores from preoperative levels to latest followup (14 ± 1 versus 16 ± 2, mean difference 2 points with a 95% confidence interval [95% CI] -3 to 7, p < 0.001). Six hips showed progression of osteoarthritis. Cumulative survivorship (hips free from conversion to THA, progression of osteoarthritis, or poor clinical outcome) of hips treated with hip arthroscopy for FAI at a mean followup of 7 years was 81% (95% CI, 68%-95%). Two patients (two hips, 4%) underwent THA at 7 and 9 years, respectively. An increased preoperative acetabular coverage (LCE angle, AI), increased offset in the superior portion of the femoral neck (pistol grip deformity), and a remaining pistol grip deformity postoperatively were associated with revision surgery. Any treatment of the labrum did not influence the outcome. Factors associated with failure could not be identified. CONCLUSIONS: In this series of patients with arthroscopic treatment of symptomatic FAI, hip arthroscopy resulted in an intact hip without progression of osteoarthritis and with a Merle d'Aubigné score of ≥ 15 points in 81% of patients at 7-year followup. Increased acetabular coverage and femoral pistol grip deformity were risk factors for revision surgery. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Functional recovery following primary ACL repair with dynamic intraligamentary stabilization.

BACKGROUND: Recently, a new technique, dynamic intraligamentary stabilization (DIS) was introduced for the acute repair of ACL ruptures. The purpose of this study was to report the functional recovery for patients undergoing acute anterior cruciate ligament (ACL) repair alongside DIS. METHODS: Forty five patients sustaining acute ACL rupture and treated with DIS repair were retrospectively evaluated. Limb symmetry index of the hop test as well as knee function by means of range of motion, knee swelling, pain and maximum strength were evaluated. Following completion of the rehabilitation program, the difference in anterior-posterior translation (Δ-AP Translation), IKDC, Tegner score (TAS) was additionally analyzed. RESULTS: Forty five (13 females, 32 males) patients were included in the study. Mean age was 26years (range 18 to 54years). Median time to successfully complete hop test was 22.0weeks (range 11 to 32weeks) postoperatively. Median limb symmetry index 91.6%±8.3%. Median delta anterior-posterior translation compared to the healthy side was plus 0.0mm±1.6mm. Median IKDC was 89.5±6.5. Mean Tegner score (TAS) at 12months of follow-up was seven (range four to nine). Three patients suffered a rerupture during the first 12 postoperative months. CONCLUSIONS: DIS technique with proper rehabilitation following acute ACL rupture provides successful functional recovery and low rerupture rate at one-year follow-up.

The hundred most cited publications in orthopaedic hip research - a bibliometric analysis.

BACKGROUND: The aim of this study was to identify the 100 most cited classics in the field of hip research analysing their qualities and characteristics. METHODS: Hip joint related articles were identified and the hundred most cited selected for subsequent analysis of citation count, current citation rate, citation density (citations/article age), authorship, geographic origin institution, and level of evidence (LOE). RESULTS: In a total of 121 journals, 1,311,851 articles were published between 1945 and 2013, of which 1,287 (0.1%) possessed 250 citations or more. Total citations per article for the 100 most-cited ranged from 290 to 3,144 citations.The most common areas of research were degenerative disease and arthroplasty, followed by hip preserving surgery for which the leading authors were William H. Harris and Reinhold Ganz respectively. All articles were published in 8 journals and originated from 9 countries. 10 institutes published 48/100 of the articles. There was a significant negative correlation between both citation rate, citation density and article age. Total citation count was highest for articles published in the decade of 1970. Although 5% (2,103 articles) of hip literature comprised randomised trials (RCTs), only 1 (1%) of the citation classics was an RCT. CONCLUSIONS: The study provides intellectual milestones in hip research, reflecting on the qualities and characteristics of the research. Degenerative hip disease and arthroplasty research take up the greatest proportion of citations, followed by hip preserving research. LOE was low and there was only one RCT amongst the classics, emphasising that high LOE is not a prerequisite for a high citation count.

Intraoperative Evaluation of Acetabular Morphology in Hip Arthroscopy Comparing Standard Radiography Versus Fluoroscopy: A Cadaver Study.

PURPOSE: To compare quantitative measurements of acetabular morphology obtained using intraoperative fluoroscopy, to standardized anteroposterior (AP) pelvis radiographs. METHODS: Ten dried human pelvis specimens (20 hips) were imaged using hip-centered fluoroscopy and standardized AP pelvis radiographs. Each hip was evaluated for acetabular version and coverage, including lateral center edge (LCE) angle, acetabular index (AI), total anterior and posterior coverage, and crossover sign. RESULTS: No statistically significant differences existed between the mean LCE angle (fluoroscopy 36.5° ± 8.3° v plain films 36.1° ± 7.9°, P = .59), acetabular index (0.6° ± 8.6° v 0.2° ± 7.1°, P = .61), ACM angle (44.0° ± 2.6° v 44.1° ± 3.8°, P = .89), Sharp's angle (31.8° ± 5.7° v 32.4° ± 3.9°, P = .44), and the total femoral coverage (80.9% ± 6.4% v 80.7% ± 7.5%, P = .83). Conversely, total anterior coverage (30.7% ± 8.5% v 33.3% ± 8.2%, P < .0001) appeared significantly decreased and the total posterior coverage (54.1% ± 6.9% v 49.1% ± 7.8%, P < .0001) appeared significantly increased in fluoroscopy compared with plain film radiographs. Fluoroscopy also failed to identify the presence of a crossover sign in 30% and underestimated the retroversion index (9% ± 16%, v 13% ± 16%, P = .016). CONCLUSIONS: The values for the LCE angle and AI determined by hip-centered fluoroscopy did not differ from those obtained by standardized AP plain film radiography. However, fluoroscopy leads to a more anteverted projection of the acetabulum with significantly decreased total anterior coverage, significantly increased total posterior coverage, and underestimated signs of retroversion compared with standardized AP pelvis radiography. CLINICAL RELEVANCE: This study shows reliable LCE and AI angles but significant differences in the projected anteversion of the acetabulum between standardized AP pelvis radiography and hip-centered fluoroscopy.

Anteverting Periacetabular Osteotomy for Acetabular Retroversion.

INTRODUCTION: The periacetabular osteotomy procedure reorients a retroverted acetabulum into a more anatomically appropriate position. STEP 1 EVALUATION OF ACETABULAR RETROVERSION: Evaluate acetabular retroversion on the basis of a combination of radiographic signs. STEP 2 PATIENT POSITIONING AND SKIN INCISION: After draping and sterile preparation with the patient in a supine position, make an incision following the skin lines of the inguinal fold. STEP 3 EXPOSURE OF THE DEEP MUSCLE LAYERS AND THE PELVIC BRIM: Detach the abdominal wall muscles from the anterior iliac crest and detach the sartorius muscle and the inguinal ligament to expose the iliac fossa and the pelvic brim. STEP 4 SURGICAL DISSECTION FOR PREPARATION OF THE ISCHIAL OSTEOTOMY: Detach the iliocapsularis muscle and mobilize it medially to allow access to the infra-articular space and palpation of the ischial bone. STEP 5 INCOMPLETE PARTIAL ISCHIAL OSTEOTOMY: Introduce a curved chisel with a crescent-shaped tip into the infra-articular space in order to perform the osteotomy of the ischial bone. STEP 6 OSTEOTOMY OF THE SUPERIOR PUBIC RAMUS: Place subperiosteal blunt retractors around the superior pubic ramus to ensure safe and complete pubic bone osteotomy. STEP 7 SUPRA-ACETABULAR AND RETROACETABULAR OSTEOTOMY: Start the supra-acetabular horizontal osteotomy at the anterior superior iliac spine and end it 2 cm lateral to the pelvic brim, where the osteotomy is angled 100° distally. STEP 8 MOBILIZATION OF THE ACETABULAR FRAGMENT: With the help of a spreader and a 4.5-mm threaded Schanz pin, free and mobilize the acetabular fragment. STEP 9 REORIENTATION OF THE ACETABULAR FRAGMENT: Perform internal rotation of the acetabular fragment with the help of the threaded Schanz pin. STEP 10 IMPROVEMENT OF ANTERIOR HEAD-NECK OFFSET FEMORAL NECK OSTEOPLASTY: Anterior capsulotomy and improvement of anterior head-neck offset is recommended when internal rotation is <30°. STEP 11 ANTEROPOSTERIOR PELVIC RADIOGRAPH FOLLOWING PERIACETABULAR OSTEOTOMY: Ideally, a postoperative radiograph should show negative crossover and posterior wall signs while the ischial spine sign typically remains positive. RESULTS: The long-term results of the periacetabular osteotomy in a series of twenty-two patients (twenty-nine hips) with symptomatic acetabular retroversion were evaluated after a mean duration of follow-up of eleven years (range, nine to twelve years).IndicationsContraindicationsPitfalls & Challenges.

Anteverting periacetabular osteotomy for symptomatic acetabular retroversion: results at ten years.

BACKGROUND: Acetabular retroversion is associated with pincer-type femoroacetabular impingement and can lead to hip osteoarthritis. We report the ten-year results of a previously described patient cohort that had corrective periacetabular osteotomy for the treatment of symptomatic acetabular retroversion. METHODS: Clinical and radiographic parameters were assessed preoperatively and at two and ten years postoperatively. A Kaplan-Meier survivorship analysis of the twenty-two patients (twenty-nine hips) with a mean follow-up (and standard deviation) of 11 ± 1 years (range, nine to twelve years) was performed. In addition, a univariate Cox regression analysis was done with conversion to total hip arthroplasty as the primary end point and progression of the osteoarthritis, a fair or poor result according to the Merle d'Aubigné score, or the need for revision surgery as the secondary end points. RESULTS: The mean Merle d'Aubigné score improved significantly from 14 ± 1.4 points (range, 12 to 17 points) preoperatively to 16.9 ± 0.9 points (range, 15 to 18 points) at ten years (p < 0.001). There were also significant improvements with regard to hip flexion (p = 0.003), internal rotation (p = 0.003), and adduction (p = 0.002) compared with the preoperative status. No significant increase of the mean Tönnis osteoarthritis score was seen at ten years (p = 0.06). The cumulative ten-year survivorship, with conversion to a total hip arthroplasty as the primary end point, was 100%. The cumulative ten-year survivorship in achievement of one of the secondary end points was 71% (95% confidence interval, 54% to 88%). Predictors for poor outcome were the lack of femoral offset creation and overcorrection of the acetabular version resulting in excessive anteversion. CONCLUSIONS: Anteverting periacetabular osteotomy for acetabular retroversion leads to favorable long-term results with preservation of the native hip at a mean of ten years. Overcorrection resulting in excessive anteversion of the hip and omitting concomitant offset creation of the femoral head-neck junction are associated with an unfavorable outcome.

Periacetabular osteotomy: a review of swiss experience.

Symptomatic dysplasia of the hip and acetabular retroversion are possible causes of osteoarthritis in the young adult. Surgical management with reorientation of the acetabulum allows causal therapy of the deformity and preservation of the native hip joint. The Ganz' periacetabular osteotomy permits a free 3-dimensional reorientation of the acetabulum and respects the blood supply of the acetabular fragment. The posterior column remains intact with a stable fixation of the acetabular fragment and a preserved shape of the true pelvis. There is a significant learning curve with severe complications in up to 30 % of cases. Good results can be expected in the long-term follow-up if performed with correct indication at young age in hips with preserved joint cartilage and proper reorientation of the acetabular fragment. Overall survivorship is superior to the natural course of hip dysplasia with a preserved hip joint in 61 % after 20 years.

In vitro temperature evaluation during cement augmentation of proximal humerus plate screw tips.

BACKGROUND: The treatment of proximal humerus fractures in patients with poor bone quality remains a challenge in trauma surgery. Augmentation with polymethylmethacrylate (PMMA) cement is a possible method to strengthen the implant anchorage in osteoporotic bone and to avoid loss of reduction and reduce the cut-out risk. The polymerisation of PMMA during cement setting leads, however, to an exothermic reaction and the development of supraphysiological temperatures may harm the bone and cartilage. This study addresses the issue of heat development during augmentation of subchondrally placed proximal humerus plate screws with PMMA and the possible risk of bone and cartilage necrosis and apoptosis. METHODS: Seven fresh frozen humeri from geriatric female donors were instrumented with the proximal humerus interlocking system (PHILOS) plate and placed in a 37°C water bath. Thereafter, four proximal perforated screws were augmented with 0.5 ml PMMA each. During augmentation, the temperatures in the subchondral bone and on the articular surface were recorded with K-type thermocouples. The measured temperatures were compared to threshold values for necrosis and apoptosis of bone and cartilage reported in the literature. RESULTS: The heat development was highest around the augmented tips of the perforated screws and diminished with growing distance from the cement cloud. The highest temperature recorded in the subchondral bone reached 43.5°C and the longest exposure time above 42°C was 86s. The highest temperature measured on the articular surface amounted to 38.6°C and the longest exposure time above 38°C was 5 min and 32s. CONCLUSION: The study shows that augmentation of the proximal screws of the PHILOS plate with PMMA leads to a locally limited development of supraphysiological temperatures in the cement cloud and closely around it. The critical threshold values for necrosis and apoptosis of cartilage and subchondral bone reported in the literature, however, are not reached. In order to avoid cement extravasation, special care should be taken in detecting perforations or intra-articular cracks in the humeral head.

Arthroscopic versus open cam resection in the treatment of femoroacetabular impingement.

PURPOSE: The purpose of this study was to evaluate if osseous correction of the femoral neck achieved arthroscopically is comparable to that achieved by surgical dislocation. METHODS: We retrospectively analyzed all patients who were treated with hip arthroscopy or surgical dislocation for cam or mixed type femoroacetabular impingement (FAI) in our institution between 2006 and 2009. Inclusion criteria were complete clinical and radiologic documentation with standardized radiographs. Group 1 consisted of 66 patients (49 female patients, mean age 33.8 years) treated with hip arthroscopy. Group 2 consisted of 135 patients (91 male patients, mean age 31.2 years) treated with surgical hip dislocation. We compared the preoperative and postoperative alpha and gamma angles, as well as the triangular index. Mean follow-up was 16.7 months (range, 2 to 79 months). RESULTS: In group 1, the mean alpha angle improved from 60.7° preoperatively to 47.8° postoperatively (P < .001) and the mean gamma angle improved from 47.3° to 44.5° (P < .001). Over time, the preoperative mean alpha angle increased from 56.3° in 2006 to 67.5° in 2009, whereas the postoperative mean alpha angle decreased from 51.2° in 2006 to 47.5° in 2009. In group 2, the mean alpha angle improved from 75.3° preoperatively to 44.8° postoperatively (P < .001), and the mean gamma angle improved from 65.1° to 52.2° (P < .001). Arthroscopic revision of intra-articular adhesions was performed in 4 patients (6.1%) in group 1 and 16 patients (12%) in group 2. Three patients (2.2%) in group 2 underwent revision for nonunion of the greater trochanter. CONCLUSIONS: Osseous correction of cam-type FAI with hip arthroscopy is comparable to the correction achieved by surgical hip dislocation. There is a significant learning curve for hip arthroscopy, with postoperative osseous correction showing improved results with increasing surgical experience. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Hip capsule dimensions in patients with femoroacetabular impingement: a pilot study.

BACKGROUND: Joint-preserving hip surgery, either arthroscopic or open, increasingly is used for the treatment of symptomatic femoroacetabular impingement (FAI). As a consequence of surgery, thickening of the joint capsule and intraarticular adhesions between the labrum and joint capsule and between the femoral neck and the joint capsule have been observed. These alterations are believed to cause persistent pain and reduced range of motion. Because the diagnosis is made with MR arthrography, knowledge of the normal capsular anatomy and thickness on MRI in patients is important. To date there is no such information available. QUESTIONS/PURPOSES: The purpose of this study was to establish thickness, length of the hip capsule, and the size of the perilabral recess in patients with FAI. METHODS: We reviewed the preoperative MR arthrography of 30 patients (15 men) with clinical symptoms of FAI. We measured capsular thickness and made observations on the perilabral recess. RESULTS: The joint capsule was thickest (6 mm) anterosuperiorly between 1 and 2 o'clock. The average length from the femoral head-neck junction to the femoral insertion of the capsule ranged from 19 to 33 mm. A perilabral recess was present circumferentially, even across the acetabular notch, where the labrum is supported by the transverse acetabular ligament. The shortest recess occurred superiorly. CONCLUSIONS: Knowledge of the capsular anatomy in patients with FAI before surgery is important to judge the postoperative changes and to plan potential further therapy including arthroscopic treatment of intraarticular adhesions.

Does bone wax induce a chronic inflammatory articular reaction?

BACKGROUND: Bone wax is used to control femoral neck bleeding during open femoroacetabular impingement (FAI) surgery. Despite its widespread use, only a few case reports and small case series describe side effects after extraarticular use. It is unclear whether intraarticular use of bone wax leads to such complications. However, during revision FAI surgery, we have observed various degrees of articular inflammatory reactions. QUESTIONS/PURPOSES: We therefore investigated whether the bone wax used intraarticularly to control femoral neck bleeding during FAI surgery could be associated with the inflammatory reactions observed at revision surgery. METHODS: We visually inspected the area and analyzed biopsy specimens from all 14 patients undergoing revision surgery from March 2005 to March 2006, 11 of whom had bone wax used at the time of original surgery. The three patients who did not have bone wax were used as controls. RESULTS: Bone wax was identified macroscopically on the femoral neck at the time of the revision surgery in all 11 patients. In all 11 patients, biopsy results indicated a foreign body-type chronic synovial inflammation. Five patients also had an associated synovial lymphoplasmacytic inflammatory reaction. No inflammatory reaction was observed in the biopsy specimens obtained from the three patients in whom bone wax was not originally used. CONCLUSIONS: Our findings suggest a synovial foreign body reaction, with or without an associated lymphoplasmacytic chronic inflammatory reaction, may be associated with intraarticular use of bone wax.

Pelvic morphology differs in rotation and obliquity between developmental dysplasia of the hip and retroversion.

BACKGROUND: Developmental dysplasia of the hip (DDH) and acetabular retroversion represent distinct acetabular pathomorphologies. Both are associated with alterations in pelvic morphology. In cases where direct radiographic assessment of the acetabulum is difficult or impossible or in mixed cases of DDH and retroversion, additional indirect pelvimetric parameters would help identify the major underlying structural abnormality. QUESTIONS/PURPOSES: We asked: How does DDH and retroversion differ with respect to rotation and coronal obliquity as measured by the pelvic width index, anterior inferior iliac spine (AIIS) sign, ilioischial angle, and obturator index? And what is the predictive value of each variable in detecting acetabular retroversion? METHODS: We reviewed AP pelvis radiographs for 51 dysplastic and 51 retroverted hips. Dysplasia was diagnosed based on a lateral center-edge angle of less than 20° and an acetabular index of greater than 14°. Retroversion was diagnosed based on a lateral center-edge angle of greater than 25° and concomitant presence of the crossover/ischial spine/posterior wall signs. We calculated sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve for each variable used to diagnose acetabular retroversion. RESULTS: We found a lower pelvic width index, higher prevalence of the AIIS sign, higher ilioischial angle, and lower obturator index in acetabular retroversion. The entire innominate bone is internally rotated in DDH and externally rotated in retroversion. The areas under the ROC curve were 0.969 (pelvic width index), 0.776 (AIIS sign), 0.971 (ilioischial angle), and 0.925 (obturator index). CONCLUSIONS: Pelvic morphology is associated with acetabular pathomorphology. Our measurements, except the AIIS sign, are indirect indicators of acetabular retroversion. The data suggest they can be used when the acetabular rim is not clearly visible and retroversion is not obvious. LEVEL OF EVIDENCE: Level III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.