Purpose: The position of the femoral implant in external rotation remains a controversial issue. It can be determined using bone landmarks (Whiteside line, parallel to the biepicondylar axis, 3° external rotation from the posterior condylar plane). For the last seven years, we have related femoral rotation to the orientation of the tibial cut in order to ensure good femorotibial stability in flexion using specific instruments (Cores®). This prospective study was conducted to examine the position of the femoral implant determined with this method and to measure the position from bone landmarks.

Material and methods: Twenty consecutive patients were included in this study. Bilateral computed tomographic measurements were made before and after surgery. Joining 8mm/8 slices were obtained for the femoral necks and 5mm/3 slices for the knees. The angle of femoral torsion was defined in two ways: the first by the angle formed between the axis of the femoral neck (on two superimposed slices) and the tangent to the most posterior part of the femoral condyles; the second by the angle formed between the epidondylar line and the posterior condylar line.

Results: The preoperative scans demonstrated that the angle between the biepicondylar line and the posterior condylar line was 5.8±1.5°. Using Cores®, led to an external rotation of the femoral implant to 2.7±0.6°. The postoperative scans demonstrated that the angle between the biepicondylar line and the posterior condylar prosthetic play was a mean 3.3°. The measurements using the femoral neck were less precise, with, in one case, an external rotation of 5°. The patella was well balanced postoperatively (irrespective of the external rotation position of the femoral implant).

Discussion: The angle of about 6° between the biepicondylar line and the posterior plane of the condyles has also been reported by others (Beaufils, Matsuda). To obtain a rectangular space in flexion, the posterior condyle cuts are more important medially than laterally. We found a correlation between the correction provided by the specific instrument set and the difference in the posterior condyle cuts, demonstrating the intraoperative precision of Cores®. It is difficult to orient the femoral piece parallel to the biepicondylar axis. This study demonstrates that there always remains 2 to 3° of inclination of the biepi-condylar axis from the posterior condylar plane.

Conclusion: The positioning the femoral implant parallel to the biepicondylar line leads to inducing an important external rotation. While using 3° rotation systematically would reduce the risk of internal malrotation, we feel it better to adapt the rotation to each individual knee depending on the anatomic presentation. Cores® enables positioning the femoral implant in external rotation as a function of the ligament balance obtained in flexion after peripheral tension is applied. This enables avoiding medial femorotibial laxity in flexion.

Purpose: Free patellar tendon plasty is classically used for the treatment of chronic anterior instability of the knee. Good functional results may however be compromised by invalidating anterior pain. The purpose of this randomised trial was to obtain a prospective comparison of outcome after hamstring plasty or patellar tendon plasty.

Material and methods: One hundred patients with an isolated tear of the anterior cruciate ligament were included in the study between May 1998 and 2001. Exclusion criteria were history of fracture, grade II laxity, and tear of the contralateral ACL. Patients were assigned to one of the treatment arms in random order in the operating room: Group A: arthroscopic free patellar tendon-bone graft; Group B: arthroscopic free four-strand hamstring graft. Two metal interference screws were used for fixation in all cases. The Aglietti method was used to calculate the position of the bore holes in all cases. The same rehabilitation protocol, in the same centre, was applied in all cases. The two groups were comparable for epidemiological, clinical, radiological, and instrumental laxity (KT1000®) data. IKDC criteria, activity level (sports), and instrumental measurement of laxity (KT1000® Medtronic) were used to assess outcome. Differences were considered significant for p < 0.05.

Results: At mean follow-up (24 months, range 6 – 38) groups A and B were not significantly different for delay to resumed sports activity at the initial level, motion, clinical examination of ligaments, IKDC global score, and radiological evolution. At six months, 30% of the patients in group A complained of anterior pain; 20% of the patients still complained of pain at one year. In group B, femoropatellar pain or pain at the harvesting site was reported by 8% of the patients at six months and 4% at one year (p = 0.0005). These differences were no longer present at two years. The instrumental differential laxity was 0.66±1.1 mm in group A and 1±1.5 mm in group B (p =0.20). Two repeated trauma-induced tears were observed in group B.

Conclusion: The preliminary results of this prospective randomised trial confirm the low morbidity of the harvesting site for hamstring grafts and the reliable stability of hamstring repair of isolated ACL laxity. A longer follow-up is however needed for long-term validation, particular concerning secondary distension of hamstring grafts as is frequently reported in the literature and which we have also observed in certain patients treated before this series.

Purpose: After cementing, various changes are observed in femoral bone resulting from various factors (ageing process, stress forces, granuloma…). The purpose of this work was to examine the radiological expression of these changes a mean 12 years after prosthesis implantation.

Material and methods: Charnley-Kerboull total hip arthroplasty was performed in 304 patients (338 hips) between January 1st, 1984 and December 31st, 1986. Mean age of the population was 65.5 years. Most of the patients had degenerative hip disease (81.4%). Among these 304 patients, 108 had died and 56 were lost to follow-up, giving 174 patients retained for analysis at a maximum follow-up of 16 years (mean 12 years). Noble and Nordin scores were recorded before surgery and during follow-up as were the cortical and cement thicknesses in the seven zones described by Gruen.

Results: The actuarial curve, calculated for the 338 hips showed 95.1% survival at 12 years (taking into account all revisions irrespective of the cause). Femoral stem survival was 97.1±2% taking certain or probable loosening as the endpoint. Several categories or radiological changes were observed: – femoral defects (18%) correlated with cup wear; – progressive widening of the medullary canal without loosening and a mean femoral score moving from 55.7 to 52.16 (p< 0.01) especially in thin women and for wide-mouthed femurs; – cortical thickening near the tip (57%) more frequently for greater distal filling; – stress shielding especially in women (p< 0.001) with a low initial score for the femur (p< 0.0006) and with greater distal filling.

Conclusion: Like Kerboull, we tried to achieve primary stem stability before cementing. Cementing results were good (97% at 12 years), but detailed radiographic analysis demonstrated that cortical thinning remained in zone 7, especially when the primary stability was achieved in the distal portion of the femur (high preoperative Noble index). Variations in the metaphyseal-diaphyseal ratio require adaptating the form of the stem to be cemented in order to achieve better filling and avoid primary stability mainly in the distal portion.