Screw Fixation of Os Acetabuli: An Arthroscopic Technique

Current concepts in the diagnosis and management of Os Acetabuli

PURPOSE

The aim of this review is to appraise the current evidence on the epidemiology, pathophysiology, diagnosis and management of os acetabuli.

METHODS

A scoping review was conducted according to the Joanna Briggs Institute guidelines. A systematic search was performed on Medline (PubMed), Embase and Cochrane Library. Inclusion criteria comprised observational and interventional studies and review articles published in the English language that focused on patients with os acetabuli according to the PRISMA extension of scoping reviews checklist using the terms 'Os Acetabuli' or 'os acetabula' or 'acetabular ossicles'. A narrative synthesis of results was undertaken, and the included articles were divided into (i) definition, (ii) aetiology, (iii) diagnosis and imaging and (iv) management of os acetabuli.

RESULTS

107 articles were screened, with 22 meeting the eligibility criteria. A total of 8836 patients were considered, of which 604 had os acetabuli. The mean age was 32.8 years. The prevalence of os acetabuli ranged from 3.4 to 7.7%, with a higher prevalence in males compared to females. True os acetabuli was defined as an unfused secondary ossification centre along the acetabular rim. The aetiology of os acetabuli is thought to be secondary to acetabular dysplasia and/or femoroacetabular impingement. Standard of care for management of symptomatic os acetabuli is considered to be arthroscopic excision unless the excision results in acetabular undercoverage and/or instability, in which case, fixation is recommended.

CONCLUSIONS

Successful management of os acetabuli depends on understanding the pathology and treating the underlying cause rather than treating the os acetabuli in isolation. Future work needs to focus on establishing clear diagnostic criteria, consensus on definition and an evidence-based treatment algorithm.

Arthroscopic Suture Fixation of Os Acetabuli With Absorbable Suture Anchors-A Double-Pulley Technique

Os acetabuli is a bone fragment with unknown origin and isolated at the acetabular rim that may be associated with cam-type femoroacetabular impingement. If this bone fragment is too large and threatens the stability of the hip joint after resection, fixation would be recommended. However, conventional rigid fixation with metal screws has some disadvantages. We describe an arthroscopic suture fixation of the Os acetabulum with absorbable anchors penetrating the bone fragment and secured by tying knots in a double-pulley fashion simultaneously. This technique provides a new feasible solution for the fixation of Os acetabuli, avoiding any metal implants and potential damage to the joint.

Os acetabuli-a new arthroscopic treatment option for the acetabular rim fracture

Os acetabuli (Os) or acetabular rimfractures are often seen in femoroacetabular impingement patients and can result in groin pain. When seen in symptomatic patients, the question is whether to remove them or to fixate the loose fragment to the acetabular rim. This depends on acetabular coverage and the extent of the Os. If removal of the Os might lead to hip dysplasia and instability, fixation of the Os should be the goal. This technical article describes the author's technique in fixating the Os with a suture-bridge technique.

Arthroscopic Management for Acetabular Rim Stress Fracture and Osteochondritis Dissecans in the Athlete With Hip Dysplasia

Intra-articular lesions are common in patients with acetabular hip dysplasia. Rim stress fractures (RSFs) have also been described in patients with acetabular hip dysplasia. This lesion is believed to be a result of an unfused secondary ossification center or a stress fracture that could be caused by repetitive impingement of an abnormal-shaped femoral head-neck junction. In addition, osteochondritis dissecans of the acetabulum is a rare condition that can also result from impingement and has been described in patients with hip dysplasia. Here, we describe an arthroscopic technique for internal fixation of osteochondritis dissecans of the acetabulum and concomitant RSF associated with hip dysplasia in a rhythmic gymnast.