Background: Paralysis of the crural nerve secondary to a compressive haematoma of the psoas in the pelvis is a well-known complication of anticoagulant therapy. This complication has also been described after hip or pelvic surgery. Its occurrence in a context of trauma is exceptional.

Case report: A 16-year-old female adolescent sought emergency care for total deficit of knee extension. The patient had an enlarged painful knee subsequent to a skateboard fall. She reported knee trauma involving the patella and a direct shock to the homolateral hip, on the trochanter. Physical examination confirmed the knee and hip pain. Rest was advised. One and a half month after the accident, the patient again consulted for total deficit of active knee extension. The initial diagnosis suggested was posttraumatic rupture of the patellar tendon. An emergency MRI was normal, ruling out this diagnosis. More attentive physical examination revealed the presence of a complete paralysis of the quadriceps muscle by crural nerve palsy. MRI of the pelvic region revealed the presence of a voluminous haematoma of the psoas compressing the crural nerve. Emergency evacuation of the haematoma was performed. The patient underwent rehabilitation for one year and achieved progressive and complete recovery of the quadriceps function. An electromyogram obtained at one year was normal.

Conclusion: This was an exceptional case of crural nerve palsy secondary to a posttraumatic haematoma of the psoas, with no notion of anticoagulation therapy. The initial knee injury was misinterpreted as involving a local patellar problem but in reality had caused a paralysis of the quadriceps muscle. MRI provided the diagnosis of psoas haematoma.

Purpose of the study: The double-bundle technique for the reconstruction of the anterior cruciate ligament (ACL) enables anatomic repair. This reconstruction may not however be possible in all patients due to the variable quality of the graft material: insufficient length and diameter. For the double-strand hamstring technique, the diameter of the posterolateral bundle (PL) can be less than 6 mm, and for the anteromedial bundle (AM) sometimes less than 7 mm. With the bundle-strand TLS larger sized grafts can be constructed in all cases.

Material and method: We operated 15 patients with full thickness tears of the ACL. The standard TLS method was used for each strand. The semitendinous and the gracilis tendons were shaped in a closed loop into short four-strand grafts measuring 45 to 50 mm. The four tunnels were reamed retrogradely arthroscopically. The graft was fixed with mersilene tape in the tunnels and locked with four titanium screws with the knee in extension for PL and 45° for AM. The diameter of each bundle was measured. Outcome was compared with that of 15 patients treated with the double-bundle technique using hamstring tendons fixed with a femoral endobutton and a tibial screw.

Results: There were no pre- or postoperative complications in the two groups. The mean diameter of the PL bundle was 6.2 mm for the endobutton group and 7.9 mm for the TLS group (p< 0.001). The diameter of each bundle with the TLS technique was thus significantly greater in the femoral notch with no deficit in postoperative extension.

Conclusion: The TLS method has already demonstrated excellent results for the single-bundle reconstruction of the ACL. The TLS double-bundle reconstruction technique provides a quality bundle with a large diameter in all patients, irrespective of the hamstring quality. The long-term results should confirm the efficacy of this double-bundle technique.

We describe three prostheses with cemented titanium-alloy stems and Al₂O₃ ceramic femoral heads which had to be revised after a mean period of implantation of 78 months. In each case, the neck of the prosthesis had been so severely worn that the profile was elliptical rather than circular. There was severe metallosis of the periprosthetic tissues. Metal particles isolated from the tissues were approximately one nanometre in size and the ratios of titanium, aluminium and vanadium in the particles were the same as in the original alloy. Histologically, the high concentration of metal particles masked the presence of high-density polyethylene (HDP) debris, but again particles about one nanometre in size were isolated from the tissues. The severe necrobiosis and necrosis noted were consistent with other reports of the presence of extensive wear particles in periprosthetic tissues. Wear is presumed to have occurred as a result of mismatch between the shape or size of the taper cone and the femoral head, or to changes in the geometry of loading due to migration of the cup. To facilitate early intervention, patients with this design of prosthesis should be monitored radiologically.