The purpose of this study is to determine the influence of knee flexion angle for drilling the posterolateral (PL) femoral tunnel during double-bundle anterior cruciate ligament (ACL) reconstruction via the anteromedial (AM) portal on resulting tunnel orientation and length. Methods: In nine fresh cadaveric knees, the ACL was excised and 2.4 mm guide wires were drilled through the PL bundle footprint via an AM portal. We compared knee flexion angles of 90, 110, 130 degrees. AP-, lateral- and tunnel view radiographs were measured to determine tunnel orientation, o’clock position, and direct measurement to determine intra-osseous tunnel length

On AP view, increased flexion resulted in more horizontal tunnels. The angles were 31.9 ± 7.1°, 26.4 ± 8.9° and 23.0 ± 8.1° for 90°, 110° and 130°. The pin orientation was significantly different when comparing 90° and 130°. On lateral view, increased flexion resulted in more horizontal tunnels. The angles were 68.9 ± 19.9°, 50.4 ± 11.6°, 31.3 ± 12.3° for 90°, 110° and 130°. On tunnel view, pin orientation was 22 ± 8.2°, 28.3 ± 6.7° and 35.9 ± 6.2° for 90°, 110° and 130°. Mean o’clock position was 09:00 ± 0:12. Intra-osseous length of the pins did not significantly change with knee flexion. The exit of the pins on the lateral femur with regard to femoral attachment of the LCL was proximal. The distance was 0.1 ± 6.6 mm, 6.4 ± 6.4 mm and 9.2 ± 2.4 mm for 90°, 110° and 130°. This was significant when comparing 90° and 130°. The shortest distance between the exit and the posterior femoral cortex was 4.0 ± 1.8 mm, 9.7 ± 3.5 mm, and 13.2 ± 2.8 mm for 90°, 110° and 130°. All values were significant. Conclusion: At 110°, exit of the PL pin is close to the attachment of the LCL. 90° flexion risks damage to the LCL and posterior cortex blow-out. Thus we recommend drilling the PL tunnel at 130° of knee flexion

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 purpose of this study was to compare the reliability and reproducibility of anterior knee laxity measurements made with the KT1000 arthrometere (Medmetric) and radiographically with Telos. The Telos measurement was taken as the standard system.

Material and methods: Inclusion criteria were preoperative anterior laxity differential less than 10 mm, a healthy contralateral knee, and intra-articular surgery. Between January 2001 and December 20001, 147 patients underwent surgery for free graft repair of anterior laxity. Both measurement methods, KT1000 and Telos were used to measure both knees before surgery and at mean 16 months postsurgery. KT1000 measurements were taken at 67N, 89N, 134N and maximum manual force. Telos was measured at 150 N as recommended by the manufacturer. A differential laxity measured at more than 3 mm was considered pathological for KT1000 and greater than 5 mm for Telos. We also determined the intrao-bserver reproducibility (experimented operators) with both methods on the 147 healthy knees considering the measurements taken preoperatively and postoperatively.

Results: Mean preoperative differential laxity was 4.2±2.4 with KT1000 at 89N and 6.3±3.1 mm at maximal manual force. It was 7.7±3.4 mm with Telos. The mean postoperative differential laxity with KT1000 was 2.1±2.2 mm at 89N and 2.6±2.5 mm at maximal manual force. With Telos it was 3±3.6 mm. The Telos values showed a wider distribution than the KT1000 values (p< 0.03). The sensitivity with Telos was 72% with 28% false negatives. With KT1000, the sensitivity improved with greater traction. It was 65% at 89N, 73% at 134N and 92% at maximal manual force. For the healthy knee, the anterior laxity measurements taken by an experimented operator were reproducible with KT1000, p=0.04, kappa = 7.8.

Discussion: The sensitivity and reproducibility results as well as the narrow distribution of the values show that KT1000 is a reliable method for the measurement of anterior knee laxity. Its use can be recommended in routine practice due to the good benefit-cost ratio. The low sensitivity is a drawback of the Telos method due to the high percentage of false negatives. Its use in routine practice should be revisited.

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°.

Aims: The purpose of this study was to determine the intra-subject repeatability of the motion pattern of the PE inlay in a mobile-bearing total knee replacement (TKR) with respect to the post-op time. Methods: 75 mobile-bearing TKRs in 73 patients were included in this prospective study. Sagittal radiographs at 0°, 30°, 60° and maximum flexion were taken 3, 12, and 24 months post-op. On each X-ray, the AP position and the rotation of the PE inlay with respect to the tibial baseplate were determined based on a 2D algorithm. The accuracy of the method was ± 0.2 mm for the AP position and ± 1.7° for the angle of rotation. To classify the repeatability, the mean AP and rotation motion with respect to the flexion angle for each patient was computed and the overall standard deviation (STD) of all measurements with respect to the mean curves was calculated. The repeatability was defined as ‘excellent’ if the STD in the AP direction was less than 0.5 mm and the STD in rotation was less than 2.5°. It was defined as ‘good’ if the STD in the AP direction was less than 1 mm and the STD in rotation was less than 5°. Results: 19 of 75 knees (25%) showed an excellent repeatability and 33 of 75 knees (44%) displayed a good repeatability of the PE motion. Motion patterns were more repeatable between the 12 and 24 month results than between the 3 and 12 month results. Conclusions: The majority of the mobile-bearing knees exhibited a repeatable, patient specific motion pattern of the PE inlay. The fact that the repeatability was higher between 12 and 24 months may be attributed to a more stable state after rehabilitation. Mobile-bearing knees support patient specific motion in contrary to constrained fixed bearing knees.

Purpose: We present the results obtained in a consecutive series of 48 patients who underwent surgical repair for chronic posterior knee laxity between 1995 and 2000.

Material and methods: The series included 33 men and 15 women, men age 29 years at the time of trauma. Mean duration of knee laxity before surgery was 32 months: 26 patients had undergone different procedures but without reconstruction of the posterior cruciate ligament (PCL). Preoperative physical examination revealed direct posterior laxity (DPL in 17 knees, posteroposterolateral laxity (PPLL) in 17, posteroposteromedial laxity (PPML) in 6, global posterior laxity (GPL) in one, and complex anteroposterier laxity (APL) in 7. The PCL was reconstructed arthroscopically using a two-strand graft using either the patellar tendon for the oldest cases (n=22) or the quadriceps tendon (n=26). Peripheral involvement was repaired by tension, reinforcement, or reconstruction with an autologous tendon graft. In the event of associated genu varum, a tibial osteotomy for normo-correction was also performed prior to the ligamentoplasty. Outcome was assessed with the IKDC 93 criteria and posterior laxity was measured on the stress x-rays.

Results: All patients were followed at least one year. Mean follow-up was 24 months. There were no postoperative complications. The principal results for the first three types of laxity, DPL, PPLL, and PPML, were as follows. Preoperative subjective evaluation for the entire series: 12C, 36D; symptoms: 6B, 10C, 32D; global score: 9C, 39D; laxity: 11.4±4.3 mm. DPL: subjective evaluation: 4C, 13D; symptoms: 2B, 2C, 12D; global score: 4C, 14D; laxity 9.9±3.3 mm. PPLL subjective evaluation: 7C, 10D; symptoms: 2B, 6C, 9D; global score: 3C, 14D; laxity 11.7±4.6 mm. PPML subjective evaluation: 6D; symptoms: 1B, 5D; global score: 6D; laxity 13.0±3.7 mm. At last follow-up for the entire series, subjective evaluation: 9A, 27B, 12C; symptoms: 6A, 26B, 14C; global score: 1A, 25B, 21C, 1D; laxity: 5.0±3.0 mm, giving a 62% gain. DPL subjective evaluation: 6A, 8B, 3C; symptoms: 5A, 10B, 2C; global score: 1A, 10B, 6C; laxity: 4.0±2.0 mm, giving a 62% gain. PPLL subjective evaluation: 2A, 11B, 14C; symptoms: 3A, 10B, 4C; global score: 4B, 12C, 1D: laxity: 5.7±3.5 mm, giving a 54% gain. PPML subjective evaluation: 6B; symptoms: 6B; global score: 5B, 1C; laxity: 5.9±3.0 mm, giving a 61% gain. For all parameters considered, category D disappeared at last follow-up in almost all knees. This improvement over the preoperative status was statistically significant (p=0.001).

Discussion: Reconstruction of the PCL with a two-strand graft combined with compensation of peripheral laxity and axial deviations provides significant correction in laxity similar to that obtained for the anterior cruciate ligament. Despite these satisfactory results, posteroposterolateral laxity has a less favourable prognosis than the other types of laxity.