Herniation pits and cystic-appearing lesions at the anterior femoral neck: an anatomical study by MSCT and microCT.

OBJECTIVE: To determine distinguishing features between herniation pits (HPs) and other cystic-appearing lesions at the anterior femoral neck in multi-slice computed tomography (MSCT) and micro-computed tomography (microCT) examinations. MATERIALS AND METHODS: Institutional review board approval was obtained to examine 37 proximal femora of 23 cadaveric specimens (mean age available in 19 cadavers, 83 years; range 68-100 years; 9 female, 8 male, 6 unknown). All 37 femora were investigated by MSCT. 23 femora, which revealed cystic-appearing lesions at the anterior femoral neck in MSCT examinations, were additionally examined by microCT. Cystic-appearing lesions were categorized by their location, sclerotic margin, demarcation and shape in MSCT with assessment of inter-observer agreement. Detailed cortical and trabecular properties were evaluated in microCT examinations. RESULTS: There were seven HPs in three femora. There were a number of abnormalities potentially imitating HPs, including focal osteoporosis (13 in 13 femora), degenerative changes (5 in 4 femora) and trabecular restructuring (5 in 4 femora) at the anterior femoral neck. HPs were differentiated on the basis of their subchondral/subcortical location, completely surrounding sclerosis, clear demarcation and round-to-oval shape in MSCT. Because of their location and their microscopic appearance, HPs seem to resemble intra-osseous ganglia at the anterior femoral neck. CONCLUSION: HPs have to be differentiated from other cystic appearing lesions at the anterior femoral neck to avoid overestimation of their incidence in the context of diagnosis of femoroacetabular impingement.

The Masquelet technique in traumatic loss of the talus after open lateral subtalar dislocation-A case report.

INTRODUCTION: Subtalar dislocations are rare injuries and treatment recommendations missing. Gross contamination and devascularisation are aspects supporting talectomy as potential treatment choice. Reconstruction in these cases can be challenging. The Masquelet technique presents one viable option. PRESENTATION OF CASE: A carpenter sustained a high energy chrush injury with traumatic open lateral talar dislocation qualifying as Gustillo Anderson type IIIc injury, a mangeled extremity index of 7 and gross contamination. The severity of soft tissue damage and contamination prompted the decision for talectomy before plastic coverage with a gracilis flap. Additionally a Masquelet procedure with cement spacer was initiated. After consolidation of the soft tissues a hindfoot arthrodesis with approximate preservation of leg length could be performed. In the course of treatment, the patient suffered no infection and could resume full weight bearing after nine months. The patient resumed his previous occupation with adapted workload and is satisfied with the treatment result. DISCUSSION: In the present case the principle options were talus preservation or talectomy with reconstruction. Talus preservation in the presence of gross contamination can be associated with the risk of infection, in addition there is a risk to develop secondary arthritis. For this individual patient the a fast and definite solution was important at this point in life. Surgeons therefore opted for talectomy. To optimally reconstruct leg length and optimize for arthrodesis the Masquelet technique was employed. CONCLUSION: The Masquelet technique is a viable option also in the emergency situation to preserve extremity length and optimize tissue viability.