Periacetabular Ossicle: Treatment Approach
Primary Recommendation
A periacetabular ossicle is typically an incidental radiographic finding that requires no treatment unless it causes symptoms or is associated with underlying acetabular dysplasia requiring surgical correction. 1
Clinical Context and Differential Diagnosis
A periacetabular ossicle must be distinguished from:
- Osteolysis from prosthetic wear - appears as expansile, well-defined lucent lesions around total hip arthroplasty components 1
- Fracture fragments - in the setting of acetabular trauma requiring surgical stabilization 2
- Metastatic lesions - requiring oncologic evaluation and potential cementoplasty or surgical stabilization 1
CT with metal artifact reduction is more sensitive than radiographs for detecting periacetabular lesions (74.7% vs 51.7% sensitivity), though MRI demonstrates even higher sensitivity at 95.4% 1. This imaging hierarchy guides workup when the clinical significance of a periacetabular ossicle is uncertain.
Treatment Algorithm
For Asymptomatic Periacetabular Ossicles
Observation with clinical follow-up is appropriate - no intervention is required for incidental ossicles without associated hip pathology 1
For Symptomatic Cases with Underlying Acetabular Dysplasia
If the ossicle is associated with symptomatic acetabular dysplasia in young adults (age <40 years) with spherically congruous pre-arthritic hips:
Periacetabular osteotomy (PAO) is the definitive treatment, which addresses the underlying dysplasia while the ossicle itself typically requires no specific management 3, 4
- Bernese PAO technique achieves radiographic correction with improvement in lateral center-edge angle from 7° to 28°, anterior center-edge angle from 18° to 28°, and acetabular index from 22° to 10° 3
- Clinical outcomes show >75% hip preservation at 18-year follow-up and improvement in Merle d'Aubigné scores from 13 to 16 points 3, 4
- Minimally invasive approaches (modified Smith-Petersen or trans-sartorial) reduce complication rates to 7% compared to traditional ilioinguinal approaches 5
For Periacetabular Lesions in Metastatic Disease Context
If imaging suggests a pathologic process rather than a benign ossicle:
Percutaneous cementoplasty with polymethylmethacrylate provides pain relief and structural reinforcement for patients with limited life expectancy or those unfit for major surgery 1, 2
- Acetabular cementoplasty is highly effective but should only be performed in the absence of fractures extensively communicating with the joint 1
- For periarticular fractures with adequate life expectancy, prosthetic replacement (total hip arthroplasty with curettage, protrusio cup, cement, and pin/screw fixation) provides predictable pain relief and return to ambulatory status 2
Key Clinical Pitfalls
Avoid confusing an incidental ossicle with pathologic osteolysis - CT or MRI clarification prevents unnecessary intervention 1
Do not perform PAO in patients with established osteoarthritis or incongruent hip joints - these patients require arthroplasty rather than joint preservation surgery 3, 6
Recognize that isolated periacetabular ossicles without dysplasia or other pathology require no treatment - the presence of an ossicle alone is not an indication for surgery 1