The Etiology of Osteoarthritis of the Hip: An Integrated Mechanical Concept

The etiology of osteoarthritis of the hip has long been considered secondary (eg, to congenital or developmental deformities) or primary (presuming some underlying abnormality of articular cartilage). Recent information supports a hypothesis that so-called primary osteoarthritis is also secondary to subtle developmental abnormalities and the mechanism in these cases is femoroacetabular impingement rather than excessive contact stress. The most frequent location for femoroacetabular impingement is the anterosuperior rim area and the most critical motion is internal rotation of the hip in 90° flexion. Two types of femoroacetabular impingement have been identified. Cam-type femoroacetabular impingement, more prevalent in young male patients, is caused by an offset pathomorphology between head and neck and produces an outside-in delamination of the acetabulum. Pincer-type femoroacetabular impingement, more prevalent in middle-aged women, is produced by a more linear impact between a local (retroversion of the acetabulum) or general overcoverage (coxa profunda/protrusio) of the acetabulum. The damage pattern is more restricted to the rim and the process of joint degeneration is slower. Most hips, however, show a mixed femoroacetabular impingement pattern with cam predominance. Surgical attempts to restore normal anatomy to avoid femoroacetabular impingement should be performed in the early stage before major cartilage damage is present. Level of Evidence: Level V, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidenc

The Concept of Femoroacetabular Impingement: Current Status and Future Perspectives

Femoroacetabular impingement (FAI) is a recently proposed mechanism causing abnormal contact stresses and potential joint damage around the hip. In the majority of cases, a bony deformity or spatial malorientation of the femoral head or head/neck junction, acetabulum, or both cause FAI. Supraphysiologic motion or high impact might cause FAI even with very mild bony alterations. FAI became of interest to the medical field when (1) evidence began to emerge suggesting that FAI may initiate osteoarthritis of the hip and when (2) adolescents and active adults with groin pain and imaging evidence of FAI were successfully treated addressing the causes of FAI. With an increased recognition and acceptance of FAI as a damage mechanism of the hip, defined standards of assessment and treatment need to be developed and established to provide high accuracy and precision in diagnosis. Early recognition of FAI followed by subsequent behavioral modification (profession, sports, etc) or even surgery may reduce the rate of OA due to FA

Algorithm for Femoral and Periacetabular Osteotomies in Complex Hip Deformities

Background: Residual acetabular dysplasia of the hip in most patients can be corrected by periacetabular osteotomy. However, some patients have intraarticular abnormalities causing insufficient coverage, containment or congruency after periacetabular osteotomy, or extraarticular abnormalities that limit either acetabular correction or hip motion. For these patients, we believe an additional proximal femoral osteotomy can improve coverage, containment, congruency and/or motion. Purposes: We provide algorithms for (1) identifying patients we believe will benefit from proximal femoral osteotomy, (2) selecting the appropriate osteotomy, and (3) choosing the sequence of these osteotomies. Methods: Anteroposterior, false-profile and functional radiographs and MR can identify most patients we believe will benefit from periacetabular and femoral osteotomies. Recently described techniques, including relative femoral neck lengthening, femoral neck osteotomy and femoral head osteotomy have expanded indications for a combined procedure. Historically performed first, periacetabular osteotomy is now frequently performed following femoral osteotomy. Results: The rate of intertrochanteric osteotomy performed with periacetabular osteotomy has decreased from approximately 10% in the first 500 surgeries to about 2% currently. Among 151 relative neck lengthenings (23 with PAO), 53 femoral neck osteotomies (4 with PAO) and 14 femoral head osteotomies (11 with PAO), eleven complications occurred including osteonecrosis in two and delayed unions in eight. No complication occurred following a combined procedure. Conclusion: Although isolated periacetabular osteotomy can provide sufficient coverage, containment and congruency for most patients with residual hip dysplasia, some may benefit from an additional proximal femoral osteotomy. Knowing the appropriate indications, selection, and sequencing of these osteotomies is critical for enhancing patient outcomes. Level of Evidence: Level V, therapeutic study. See Guidelines for Authors for a complete description of levels of evidenc

The history of femoroacetabular impingement.

AIMS: Femoroacetabular impingement (FAI) describes abnormal bony contact of the proximal femur against the acetabulum. The term was first coined in 1999; however what is often overlooked is that descriptions of the morphology have existed in the literature for centuries. The aim of this paper is to delineate its origins and provide further clarity on FAI to shape future research. METHODS: A non-systematic search on PubMed was performed using keywords such as "impingement" or "tilt deformity" to find early anatomical descriptions of FAI. Relevant references from these primary studies were then followed up. RESULTS: Although FAI has existed for almost 5,000 years, the anatomical study by Henle in 1855 was the first to describe it in the literature. The relevance of the deformity was not appreciated at the time but this triggered the development of further anatomical studies. Parallel to this, Poland performed the first surgical correction of FAI in 1898 and subsequently, descriptions of similar procedures followed. In 1965, Murray outlined radiological evidence of idiopathic cam-type deformities and highlighted its significance. This led to a renewed focus on FAI and eventually, Ganz et al released their seminal paper that has become the foundation of our current understanding of FAI. Since then, there has been an exponential rise in published literature but finding a consensus, especially in the diagnosis of FAI, has proven to be difficult. CONCLUSION: Current research on FAI heavily focuses on new data, but old evidence does exist and studying it could be equally as important in clarifying the aetiology and classification of FAI.Cite this article: Bone Joint Res 2020;9(9):572-577

Reinforcement Ring-Augmented Hip Arthroplasty: A 35-Year Follow-up.

During the late 1980s, techniques were evolving to prevent acetabular component loosening. Inadequate acetabular bone stock further complicated this concern, which was traditionally addressed with cementation and bone grafting during this time period. However, one evolving tactic to address acetabular component loosening in the setting of inadequate acetabular bone stock was to augment bone graft with an acetabular reinforcement ring. In 1963, a 26-year-old, active male sustained a right-sided femoral neck fracture following a skiing accident. He ultimately developed a collapsed femoral head and varus deformity of the femoral neck requiring a total hip arthroplasty with a cemented monoblock femoral component and a polyethylene acetabular component cemented into a reinforcement ring. The initial procedure was performed in 1988, and this prosthesis is still functioning 35 years later and represents one of the longest follow-ups of a patient with a primary total hip arthroplasty with a reinforcement ring

Die "bio-logische” Stabilisierung der subtrochantären Femurfraktur mit einer Kondylenplatte

Zusammenfassung: Operationsziel: Indirekte Reposition von subtrochantären Frakturen über die Ligamentotaxis ohne chirurgische Traumatisierung der Frakturzone (keine devaskularisierten Fragmente!) und übungsstabile Osteosynthese mit einer Kondylenplatte. Indikationen: Geschlossene und offene subtrochantäre Trümmerfrakturen des Femurs, insbesondere bei Beteiligung der Schenkelhalsbasis. Kontraindikationen: Keine, außer bei polytraumatisierten Patienten mit lebensbedrohlichen Verletzungen. Operationstechnik: Osteosynthese mit einer Kondylenplatte. Kapsulotomie, um die korrekte Position der Klinge zu prüfen. Reposition der Fraktur an den Schaft der Kondylenplatte unter Kontrolle von Länge, Rotation und Achse, aber ohne anatomische Reposition der einzelnen Fragmente. Kompression der Fraktur, falls möglich, mit dem Spanngerät. Weiterbehandlung: Frühe funktionelle Nachbehandlung mit 15 kg Teilbelastung ab zweitem postoperativen Tag. Ergebnisse: Von 1992 bis 1995 wurden 25 Patienten mit subtrochantärer Femurfraktur (Typ A: n=10; Typ B: n=8; Typ C: n=7 [nach AO-Klassifikation]; vier offene Frakturen) mit Kondylenplatte behandelt. Operationszeit: im Mittel 1,9 Stunden; intraoperativer Blutverlust: durchschnittlich 1300 ml. Normale Frakturheilung: 24/25 Patienten. Komplikationen: Infektpseudarthrose: n=1. Konsolidation der Fraktur nach mehrfachen Débridements und Reosteosynthese mit Wellenplatte. Achsenfehlstellungen: n=3 (Varus: n=2; Verkürzung: n=1; intertrochantäre Korrekturosteotomie: n=1). Entfernung der Platte wegen chronischer Trochanterirritation: n=

Mean 20-year Followup of Bernese Periacetabular Osteotomy

The goal of the Bernese periacetabular osteotomy is to correct the deficient acetabular coverage in hips with developmental dysplasia to prevent secondary osteoarthrosis. We determined the 20-year survivorship of symptomatic patients treated with this procedure, determined the clinical and radiographic outcomes of the surviving hips, and identified factors predicting poor outcome. We retrospectively evaluated the first 63 patients (75 hips) who underwent periacetabular osteotomy at the institution where this technique was developed. The mean age of the patients at surgery was 29years (range, 13-56years), and preoperatively 24% presented with advanced grades of osteoarthritis. Four patients (five hips) were lost to followup and one patient (two hips) died. The remaining 58 patients (68 hips) were followed for a minimum of 19years (mean, 20.4years; range, 19-23years) and 41 hips (60%) were preserved at last followup. The overall mean Merle d'Aubigné and Postel score decreased in comparison to the 10-year value and was similar to the preoperative score. We observed no major changes in any of the radiographic parameters during the 20-year postoperative period except the osteoarthritis score. We identified six factors predicting poor outcome: age at surgery, preoperative Merle d'Aubigné and Postel score, positive anterior impingement test, limp, osteoarthrosis grade, and the postoperative extrusion index. Periacetabular osteotomy is an effective technique for treating symptomatic developmental dysplasia of the hip and can maintain the natural hip at least 19years in selected patients. Level of Evidence: Level III, prognostic study. See the Guidelines for Authors for a complete description of levels of evidenc

Acetabular Morphology: Implications for Joint-preserving Surgery

Appropriate anatomic concepts for surgery to treat femoroacetabular impingement require a precise appreciation of the native acetabular anatomy. We therefore determined (1) the spatial acetabular rim profile, (2) the topography of the articular lunate surface, and (3) the 3-D relationships of the acetabular opening plane comparing 66 bony acetabula from 33 pelves in female and male pelves. The acetabular rim profile had a constant and regular wave-like outline without gender differences. Three prominences anterosuperiorly, anteroinferiorly and posteroinferiorly extended just above hemispheric level. Two depressions were below hemispheric level, of 9° at the anterior wall and of 21° along the posterosuperior wall. In 94% of all acetabula, the deepest extent of the articular surface was within 30° of the anterosuperior acetabular sector. In 99% of men and in 91% of women, the depth of the articular surface was at least 55° along almost half of the upper acetabular cup. The articular surface was smaller in women than in men. The acetabular opening plane was orientated in 21° ± 5° for version, 48° ± 4° for inclination and 19° ± 6° for acetabular tilt with no gender differences. We defined tilt as forward rotation of the entire acetabular cup around its central axis; because of interindividual variability of acetabular tilt, descriptions of acetabular lesions during surgery, CT scanning and MRI should be defined and recorded in relation to the acetabular notch. Acetabular tilt and pelvic tilt should be separately identified. We believe this information important for surgeons performing rim trimming in FAI surgery or performing acetabular osteotomie

Traumatic labral avulsion from the stable rim: a constant pathology in displaced transverse acetabular fractures

Introduction: During the treatment of a malunited transverse acetabular fracture, a hitherto undescribed extended avulsion of the labrum from the stable acetabular fragment was found. Based on the labral pathomorphology present in this case, the hypothesis was put forward that traumatic acetabular labral avulsions are a constant phenomenon in transverse acetabular fractures. Patients and methods: Fourteen patients underwent capsulotomy and/or surgical dislocation of the involved hip to facilitate open reduction and internal fixation of transverse acetabular fractures. Results: In all cases, the labrum was partially or completely detached from the superior acetabular rim. In eight cases with bucket-handle tears of the labrum from the stable superior fragment, the injured portion was resected back to normal margins. In one case the labrum was avulsed with an attached piece of bone and was repaired by screw fixation. Small separations of the labrum from the underlying acetabular rim occurred at the level of the fractures in five cases with minor displacement and received no treatment. Conclusion: With displaced transverse acetabular fractures, consideration should be given to opening the joint at the time of open reduction and internal fixation to look for associated intracapsular injuries. An avulsed portion of the labrum should be left if stable and undamaged. If unstable and damaged, it is probably better resected and if unstable but intact and/or attached to a bony fragment, it should be repaire