Os acetabuli and femoro-acetabular impingement: aetiology, incidence, treatment, and results.

PURPOSE: The purpose of this study was to investigate the pathogenesis, the incidence, and the results of arthroscopic treatment of os acetabuli (OSA) in a group of patients with diagnosis of femoro-acetabular impingement (FAI). METHODS: We retrospectively analyzed the full documentation of 294 hips in 273 patients (21 bilateral) operated for FAI through hip arthroscopy. We reviewed all radiographs and arthro-MRI in order to identify the incidence of OSA. All patients with OSA were then assessed with a modified Harris hip score (MHHS) pre-operatively and at the final follow-up. RESULTS: Twenty-one patients (7.7%), 20 (95%) of them were male, were diagnosed with concomitant FAI and os acetabuli. In 21 cases, OSA was excised and FAI was treated with rim trimming, femoral osteoplasty, or both. In one case, a large OSA fragment was fixed with a 4 mm screw avoiding an acetabular uncoverage if excised. The average follow-up was 31 months (range from 6 to 69 months). The MHHS showed an improvement from a pre-operative MHHS of 57.5 (range from 39 to 82) to 95 (range from 73 to 100). CONCLUSIONS: Os acetabuli is not uncommon and certainly associated with FAI and male gender. The etiology is probably microtraumatic. The arthroscopic OSA removal or fixation and concomitant FAI treatment showed very good results. Interestingly, these outcomes seem better than FAI treatment alone. Further studies with a wider number of patients and a longer follow-up are needed to confirm these results and understand the real role of OSA in this setting.

Bilateral femoral shaft fractures complicated by fat and pulmonary embolism: a case report.

A 25-year-old man was admitted to our hospital because of pulmonary embolism and suspected fat embolism after sustaining bilateral femoral shaft fracture. A left arm weakness, tachycardia and sudden hemoglobin drop delayed his definitive fixation with intramedullary nailing. His clinical course was further complicated by bleeding from the pin sites of the external fixators which had initially been used to temporarily stabilize his femoral fractures (clotting disturbances). A lower leg Doppler ultrasound and a new pelvic-chest CT angiography excluded any remaining thrombus, meanwhile the embolus had broken in smaller pieces, more distally. His unfractionated heparin was revised to a Low Molecular Weight Heparin at prophylactic dose. After a 10 day period and when his condition had been improved bilateral reamed nailing was performed. Although bilateral closed femoral shaft fractures should be stabilized early, fat embolism syndrome (FES) and thromboembolic events (TEV) should always be kept in mind in these patients.

Radiographically undetectable periprosthetic osteolysis with ASR implants: the implication of blood metal ions.

Patients with ASR implants (resurfacing and large-diameter (XL) metal-on-metal (MoM) total hip arthroplasty), even if asymptomatic and with a stable prosthesis, may present extremely high blood metal ion levels. We report on a consecutive series of fourteen ASR revisions, focusing on osteolysis and their radiographic correspondence and their correlation with blood metal ion levels. At revision, seven hips revealed severe periacetabular osteolysis which was radiographically undetectable in six and asymptomatic in five. Seven hips with no acetabular osteolysis had significantly lower serum Cr and Co ion concentrations (respectively 25.2, 41.1 µg/l) compared to the seven hips with severe acetabular bone loss (respectively 70.1, 147.0 µg/l). Elevated blood metal ion levels should be considered as a warning of undetectable and ongoing periprosthetic osteolysis in asymptomatic patients with ASR prosthesis.