Patients With Generalized Joint Hypermobility Have Thinner Superior Hip Capsules and Greater Hip Internal Rotation on Physical Examination

Editorial Commentary: Decreased Hip Ligament Thickness in Patients With Dysplasia May Contribute to Hip Instability, Above and Beyond Associated Acetabular Under-coverage

Hip dysplasia is a pathomorphologic deformity that leads to decreased acetabular coverage and hip instability. Many different radiographic measurements have been explored to characterize hip dysplasia, including the lateral center-edge angle, femoral-epiphyseal acetabular roof index, and Tönnis angle. Magnetic resonance imaging offers 3-dimensional characterization of the hip pathomorphology that may be more detailed than 2-dimensional radiographs, as well as a modality that is free of radiation. Recent research has shown that dysplastic hips are associated with significantly thinner ligament thickness compared with non-dysplastic hips. The iliofemoral ligament is the most important hip capsular structure and helps to stabilize the hip joint, particularly in hip extension and external rotation. Differences in iliofemoral ligament thickness may help to explain why patients with dysplasia are more prone to hip instability, above and beyond their acetabular under-coverage. This reiterates the need for routine capsular closure and/or plication in patients with femoroacetabular impingement syndrome to prevent further instability.

Female Sex, Capsular Laxity, and Heightened Beighton Test Score, Femoral Torsion Angle, Neck-Shaft Angle Decrease Whereas Hip Inflammatory Disease and Capsular Repair Increase Hip Capsular Thickness: A Systematic Review

PURPOSE

To systematically review factors affecting hip capsule thickness.

METHODS

The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The terms "hip," "arthroscopy," "capsule," "capsular," and "thickness" were used to search the PubMed, Ovid [MEDLINE], Cochrane Database, and EMBASE databases from inception to January 15, 2024.

RESULTS

The initial search identified 1,735 studies. Twenty-three studies were included in the systematic review. Eight reported the relationship between sex and capsule thickness. Seven reported that capsule thickness was significantly lower in women. Of the 4 studies reporting the relationship between capsular laxity and capsule thickness or Beighton test score (BTS), 4 studies showed the association of lower capsule thickness in patients with capsular laxity or BTS ≥4. Of the 6 studies reporting the relationship between arthroscopic surgery and capsular thickness, 2 showed significantly greater capsule thickness after capsulotomy with repair and 2 found significantly decreased postoperative capsule thickness without repair. One study illustrated that anterior capsule thickness was significantly smaller in patients with femoral torsion angle >20°. One study showed that neck-shaft angle was negatively corelated with anterior capsule thickness. Of the 3 studies that examined lateral central edge angle, 2 reported that lower angle correlated with thinner capsule thickness; one study reported the opposite result. Hip inflammatory disease was associated with thicker hip capsule.

CONCLUSIONS

Female sex, capsular laxity, BTS ≥4, greater femoral torsion angle, and greater neck-shaft angle were associated with a thinner hip capsule. Hip inflammatory disease and capsule repair after arthroscopic surgery were associated with a thicker capsule.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I-IV studies.

Advances in Molecular Research on Hip Joint Impingement-A Vascular Perspective

With the rise in longevity within the population, medicine continues to encounter fresh hurdles necessitating prompt actions, among which are those associated with hip joint aging. Age-related arthropathies encompass damage to bones' articulating extremities and their supporting structures, such as articular cartilage, and alterations in the quantity and quality of synovial fluid. This study aims to summarize the biomolecular methods of hip joint evaluation focused on its vascularization, using data correlated with biomolecular research on other joints and tissues, in order to reach an objective opinion of the study prospects in this field. Following a retrospective study on most modern biomolecular research methods on the synovium, the capsule, and the articular cartilage of the hip joint, we have hereby concretized certain future research directions in this field that will improve the qualitative and morphofunctional management of the hip joint at an advanced age, even within population categories at risk of developing various degenerative joint pathologies.

Capsular Management During Hip Arthroscopy

PURPOSE OF REVIEW

Hip arthroscopy is widely used for the management of intra-articular pathology and there has been growing interest in strategies for management of the hip capsule during surgery. The hip capsule is an essential structure that provides stability to the joint and it is necessarily violated during procedures that address intra-articular pathology. This article reviews different approaches to capsular management during hip arthroscopy including anatomical considerations for capsulotomy, techniques, clinical outcomes, and the role of routine capsular repair. This article also reviews the concept of hip microinstability and its potential impact on capsular management options as well as iatrogenic complications that can occur as a result of poor capsular management.

RECENT FINDINGS

Current research highlights the key functional role of the hip capsule and the importance of preserving its anatomy during surgery. Capsulotomies that involve less tissue violation (periportal and puncture-type approaches) do not appear to require routine capsular repair to achieve good outcomes. Many studies have investigated the role of capsular repair following more extensive capsulotomy types (interportal and T-type), with most authors reporting superior outcomes with routine capsular repair. Strategies for capsular management during hip arthroscopy range from conservative capsulotomy techniques aimed to minimize capsular violation to more extensive capsulotomies with routine capsule closure, all of which have good short- to mid-term outcomes. There is a growing trend towards decreasing iatrogenic capsular tissue injury when possible and fully repairing the capsule when larger capsulotomies are utilized. Future research may reveal that patients with microinstability may require a more specific approach to capsular management.

Arthroscopic Capsular Suture-Lifting Technique for Treating Femoroacetabular Impingement Patients With a High Risk of Postoperative Anterior Instability

With the increasing popularity of hip arthroscopy, postoperative iatrogenic instability due to bony and soft-tissue issues has been noted by more orthopaedic surgeons. Although there is a low risk of serious complications in patients with normal hip joint development even without suturing of the joint capsule, for patients with a preoperative high risk of anterior instability-including those with excessive anteversion of the acetabulum or femur, borderline dysplasia of the hip, and hip arthroscopic revision surgery with an anterior defect of the joint capsule-capsulotomy without repair will result in postoperative anterior instability of the hip joint and related symptoms. Capsular suturing techniques that provide anterior stabilization will be of great help for these high-risk patients and reduce the possibility of postoperative anterior instability. In this Technical Note, we introduce the arthroscopic capsular suture-lifting technique for treating femoroacetabular impingement (FAI) patients with a high risk of postoperative hip instability. In the past 2 years, the capsular suture-lifting technique has been used to treat FAI patients with borderline dysplasia of the hip and excessive femoral neck anteversion, and clinical results have shown that the suture-lifting technique provides a reliable and effective solution for FAI patients with a high risk of postoperative anterior hip instability.