Introduction

In total knee arthroplasty (TKA) the knee may be found to be too stiff in extension, causing a flexion contracture. One proposed surgical technique to correct this extension deficit is to recut the distal femur, but that may lead to excessively raising the joint line. Alternatively, full extension may be gained by stripping the posterior capsule from its femoral attachment, however if this release has an adverse impact on anterior-posterior (AP) stability of the implanted knee then it may be advisable to avoid this technique. The aim of the study was therefore to investigate the effect of posterior capsular release on AP stability in TKA, and compare this to the restraint from the cruciate ligaments and different TKA inserts.

Purpose: To define the positions of the attachments of the anteromedial (AM) and posterolateral (PL) bundles of the ACL facilitating accurate tunnel placement during two-bundle reconstruction.

Methods: The positions of the femoral and tibial attachments of the AM and PL bundles was determined in 7 fresh-frozen, unpaired, cadaveric knees by 6 independent observers, using landmarks visible at arthroscopy. This included, on the tibia, the retro-eminence ridge (lying just anterior to the PCL), a bony landmark that could be reliably identified arthroscopically. Tantallum beads were then inserted so that the bundle attachments could be clearly identified on a plain lateral radiograph of the knee. The position of the centres of the AM and PL attachments were described relative to Amis and Jakob’s line on the tibia and Bernard’s grid on the femur.

Results: The AM femoral attachment lay high and deep in the notch with the most posterior fibres 1.8 mm anterior to the “over–the-top” position. The PL femoral attachment was low and shallow in the notch with the most anterior fibres 2.8 mm from the border of the articular cartilage. The centres of the bundles were 8.2 mm apart. The position of the bundles relative to Bernhard’s grid is shown in figure 1.

On the tibia, the centre of the AM attachment was located 18 mm anterior to the Retro-eminence ridge (RER). The centre of the PL bundle lay 8.4 mm posterior to the centre of the AM bundle. These positions were at 35% and 52% along Amis and Jacob’s line

Conclusions: This study details the morphology of the AM and PL bundle attachments and demonstrates reliable arthroscopic techniques to assist with accurate tunnel placement in reconstruction surgery. In addition, it provides reference data for radiographic evaluation of tunnel placement.

Purpose of the study: Failure of anterior cruciate ligament (ACL) ligamentoplasty is a major surgical challenge. Over the last decade, failures have been related to the use of synthetic material, but at the present time, most of the failures observed are related to an inappropriate position for the graft. The purpose of this work was to report a prospective cohort of 44 consecutive patients where the objective and subjective results of revision surgery were recorded.

Material and methods: Between January 2000 and January 2004, 44 patients with a healthy contralateral knee were included in this study: 26 males and 18 females, mean age 30 years (range 20–53 years). The majority of the initial grafts were patellar (57%), hamstring tendons had been used for 26%. The time from the first ligamentoplasty to revision reconstruction was 38.7±28.3 months. This was a first revision for 38 patients and six patients had had multiple revisions. The preoperative IKDC scores were: subjective 51.7±16.2; overall: 1B, 19C, 24D. The maximal manual differential laxity measured with KT1000 was 8.6±3.1 mm. In 70% of cases, the cause of failure was related to an inadapted position of the graft. At revision, grade 2 or 3 cartilage lesions were observed in 50% of knees. Reconstructions were performed with autografts: patellar tendon (39%), hamstring tendons (31%), or quadricipital tendon (29%), combined with lateral ligamentoplasty in 78% of the cases.

Results: Mean follow-up in this series was 14.7 months, minimum 12 months. At last follow-up, the IKDC scores were: 73.8±13.9 for the subjective assessment and 9A, 12B, 17C, 6D for the overall assessment. 67.7% of patients were satisfied or very satisfied. The maximal manual differential laxity measured with KT1000 was 4.3±3.5 mm. All variables exhibited statistically significant improvement. Grade B or C radiologial modifications were noted in 32% of cases.

Discussion and conclusion: Complete analysis of the clinical findings searching for combined laxity as well as a precise preoperative radiological work-up is the key to a successful operative strategy. Data provided by this series confirmed that outcome is less satisfactory after revision reconstruction of the ACL than first-intention ligamentoplasty. Most of the knees involved however present cartilaginous and meniscal lesions with associated peripheral injuries. Short-term cartilage degradation is a worrisome problem and emphasizes the importance of correctly positioning the ACL graft at the primary surgery.

Purpose: The anterior cruciate ligament (ACL) is composed of two strands, the anteromedial (AM) and the posterolateral (PL). Each strand has a distinct biomechanical role. The classical techniques for reconstruction of the ACL using a one-strand graft cannot replace the AM strand of the ligament. Control of knee laxity after graft reconstruction with a single strand cannot restore physiological laxity.

Material and methods: This study was performed on 16 matched cadaver knees randomised for reconstruction technique. Anterior tibial dislocation was measured with the Rolimeter arthrometer using manual traction on the intact knee, after section of the ACL, and after arthroscopic reconstruction of the ACL using a 2-strand or 4-strand hamstring method at 20°, 60°, and 90° flexion. Changes in the length of each reconstructed strand were measured.

Results: For the 16 intact knees, anterior laxity was measured at 20°, 60° and 90°. After section of the ACL, laxity increased significantly at all angles studied. Statistical parametric and non-parametric tests demonstrated a significant difference between laxity after ACL section and after ACL reconstruction (one-strand) at 20°, 60° and 90° flexion. There was a significant difference between intact ACL and reconstructed ACL at 20° flexion, the residual laxity was greater after one-strand reconstruction. Conversely, at 60° and 90°, there was no difference in anterior displacement of the tibia for intact and reconstructed ACL. There was a statistically significant improvement in laxity between sectioned and reconstructed (two-strand) ACL at 20°, 60° and 90° but no difference in anterior dislocation between the intact ACL and the reconstructed ACL at 2°, 60°, and 90° flexion.

Conclusion: Two-strand reconstruction of the ACL provides laxity comparable with that of the intact ACL at 20°, 60°, and 90° flexion while one-strand reconstruction only re-establishes physiological laxity at 60° and 90°.