Anterior cruciate ligament (ACL) reconstruction is a commonly performed operation. A variety of graft options are used with the most popular being bone-patellar-tendon-bone and hamstring autograft. There has been an increase in the popularity of hamstring autograft over the past decade. The aim of the study was to assess the ten year subjective knee function and activity level following four-strand semitendinosis and gracilis (STG) anterior cruciate ligament reconstruction. 86 patients underwent anterior cruciate reconstruction by two knee surgeons over a 12 month period (January 1999 to December 1999). 80 patients meet the inclusion criteria of arthroscopic ACL reconstruction. The same surgical technique was used by both surgeons involving four-strand STG autograft, single femoral and tibial tunnels and aperture graft fixation with the Round headed Cannulated Interference (RCI) screw. Patient evaluation was by completion of a Lysholm Knee Score and Tegner Activity Level Scale at a minimum of ten years from reconstructive surgery. This was by initial postal questionnaire and subsequent telephone follow-up. 80 patients underwent anterior cruciate reconstruction with average age 30.9 years (15 to 58 years). There was a 77.5% (62 patients) response at ten years to the questionnaire. The median Lysholm Knee Score at ten years was 94 (52 to 100). The median activity level had decreased from 9 to 5 at ten years according to the Tegner Activity Scale. 73% of patients reported a good or excellent outcome on the Lysholm score. The group of patients was further divided into those that required meniscal surgery and those that did not. The patients that did not require meniscal surgery had a median Lysholm score of 94 and those that required meniscal surgery had a similar median Lysholm score of 92.5. However it was noted that 8 patients required medial and lateral partial menisectomies at the time of original reconstruction. This group of patients had a median Lysholm Knee Score of 83.5 and Tegner Activity Scale of 4 at ten years following reconstruction. 17 of the 62 patients (27.4%) required re-operation because of further knee symptoms, with 4 patients requiring revision of the anterior cruciate following re-rupture. In conclusion anterior cruciate ligament reconstruction with four-strand STG hamstring autograft provides a reliable method of restoring knee function, with a 6% revision rate for re-rupture at ten years. Combined partial medial and lateral menisectomy at the time of the initial reconstruction is a poor prognostic indicator of function at ten years

Introduction. Partial meniscectomy, a surgical treatment for meniscal lesions, allows athletes to return to sporting activities within two weeks. However, this increases knee joint shear stress, which is reported to cause osteoarthritis. The volumes and locations of partial meniscectomy that would result in a substantial increase in knee joint stress is not known. This information could inform surgeons when a meniscus reconstruction is required. Aim. Our aim was to use a previously validated knee finite element (FE) model to predict the effects of different volumes and locations of partial meniscectomy on cartilage shear stress. The functional point of interest was at the end of weight acceptance in walking and running, when the knee is subjected to maximum loading. Method. An FE model of the knee joint was used to simulate walking and running, two of the most common functional activities. Forces and moments, obtained from the gait cycle of a 76.4 kg male subject, were applied at the tibia. Different sizes (0%, 10%, 30%, 60%) and locations (anterior, medial and posterior) of partial meniscectomies were simulated (Figure 1). Maximum cartilage shear stress was determined for the different meniscectomies. Graphs were plotted of the cumulative tibial cartilage volume subjected to stress values above specific thresholds. Results and analysis. Maximum shear stress values for the intact knee during walking were 2.00 MPa medially and 1.71 MPa laterally. During running these magnitudes rose to 3.48 MPa medially and 4.70 MPa laterally. For a 30% anterior, central and posterior meniscectomy during walking shear stress increased by 25.9%, 44.9% and 32.5% medially, and 12.4%, 25.7% and 17.8% laterally. During running shear stress increased by 9.6%, 8.3% and 7.1%, medially and 31.6%, 37.5% and 43.6% laterally. For a 60% meniscectomy, during walking shear stress increased by 47.2% medially and 31.8%, laterally. During running shear stress increased by 10.0%, medially and 51.8%, laterally. The percentage of cartilage volume exposed to shear stress levels above a specified threshold is illustrated in Figure 2 for different volumes and locations of partial meniscectomy. Discussion and conclusions. This is first study that has estimated the volume of cartilage exposed to specific stress thresholds in walking and running as a function of the amount and location of meniscectomy. Maximum shear stress was 100% higher at the end of weight acceptance in running compared to walking. Stress was higher in the lateral compartment during running while higher in the medial compartment during walking. This is because a valgus moment acts at the knee at the end of weight acceptance in running while a varus moment acts at the joint in walking. Clinical significance. The model developed from this research has potential for applications in planning meniscal surgeries and developing rehabilitation strategies for athletes. It could inform surgeons about the safe volume and location of partial meniscectomy that can be performed before meniscus reconstruction becomes necessary. Results of this study also highlight the importance of considering the effect of post-surgical outcomes following different common functional activities