Biomechanics and anterior cruciate ligament reconstruction

For years, bioengineers and orthopaedic surgeons have applied the principles of mechanics to gain valuable information about the complex function of the anterior cruciate ligament (ACL). The results of these investigations have provided scientific data for surgeons to improve methods of ACL reconstruction and postoperative rehabilitation. This review paper will present specific examples of how the field of biomechanics has impacted the evolution of ACL research. The anatomy and biomechanics of the ACL as well as the discovery of new tools in ACL-related biomechanical study are first introduced. Some important factors affecting the surgical outcome of ACL reconstruction, including graft selection, tunnel placement, initial graft tension, graft fixation, graft tunnel motion and healing, are then discussed. The scientific basis for the new surgical procedure, i.e., anatomic double bundle ACL reconstruction, designed to regain rotatory stability of the knee, is presented. To conclude, the future role of biomechanics in gaining valuable in-vivo data that can further advance the understanding of the ACL and ACL graft function in order to improve the patient outcome following ACL reconstruction is suggested

Hip, knee, and ankle joint forces in healthy weight, overweight, and obese individuals during walking

Worldwide in 2008, more than 1.4 billion adults, age 20 and older, were overweight. Overweight and obesity are defined as abnormal or excessive fat accumulation that may impair health. The World Health Organization defines overweight as having a body mass index (BMI) greater than or equal to 25 kg/m2 and obese as a BMI greater than or equal to 30 kg/m2. The aim of this study was to compare peak hip, knee, and ankle joint compressive loads during gait at self-selected speed between overweight and healthy weight individuals and to examine the functional relationship between body mass and peak joint forces. Twelve subjects, six high BMI subjects and six normal BMI control subjects, participated in this investigation. Absolute peak hip, knee, and ankle joint forces were 40 %, 43 %, and 48 % greater, respectively, for the high-BMI versus normal group. Joint loads were found to increase approximately linearly with body mass. Body mass accounted for 70-80 % of the variation in the peak compressive load at the hip, knee, and ankle during gait. These findings support the link that increased body mass leads to increased biomechanical loading of the joints and could be a factor linking obesity to osteoarthritis

The effect of graft choice on functional outcome in anterior cruciate ligament reconstruction

A prospective, randomised, 5-year follow-up study was designed to compare the functional results between patellar tendon and hamstring tendon autografts after anterior cruciate ligament reconstruction. Primary reconstruction was performed in 32 patients using the central third of the patellar ligament and in 32 patients using double-looped semitendinosus and gracilis tendons. All reconstructions were performed by a single surgeon, with identical surgical technique and rehabilitation protocol. Of the total 64 patients in the study, 54 (85%) were available for the 5-year follow-up. No statistically significant differences were seen with respect to Lysholm score, International Knee Documentation Committee (IKDC) classification, clinical and KT-2000 arthrometer laxity testing, single-legged hop test and anterior knee pain. Graft rupture occurred in two patients (8%) in the patellar tendon group and in two patients (7%) in the hamstring tendon group; 23 patients (88%) in the patellar tendon group and 23 patients (82%) in the hamstring tendon group returned to their pre-injury activity level. Good subjective outcome and stability can be obtained by using either graft; no statistically significant differences were found in functional outcome between the grafts

Proteoglycan fragments in anterior cruciate ligament reconstructed knees: a comparative study of two different surgical techniques

WOS: 000230462400007PubMed ID: 15645213Proteoglycan fragments (PF) as chondroitin sulphate were monitored and compared in two groups of patients who had anterior cruciate ligament reconstruction with either patellar tendon (PT) or quadruple semitendinosus tendon (ST) autografts. There were 20 ST and 21 PT reconstructions. No difference existed between the groups in terms of associated lesion and time from injury to surgery. Synovial sample was collected at 6 weeks, 3 months and 18 months after the operation. No difference was noted between the groups at 18 months in terms of activity level and functional scores. Both groups demonstrated a sudden increase of PF at 6 weeks with respect to preoperative quantities (p < 0.0001). A significant decrease occurred in the PT group at 3 months (p < 0.008). Even at 18 months, it was significantly below the preoperative values (p < 0.004). However, the decrease in ST cases relative to 6 weeks was insignificant at 3 months and quantities did not drop below the preoperative levels at 18 month (p=0.79). These results confirm again a gradual decrease of PF values in PT-reconstructed knees depending on time and surgery. Reconstruction with quadruple ST does not seem to have the same effect until 18 months postoperatively. Achievement of almost the same level of activity and function in both groups does not necessarily reflect the molecular status

Anterior Cruciate Ligament Reconstruction Using Achilles Tendon Allograft: an Assessment of Outcome for Patients Age 30 Years and Older

Achilles allografts have become popular for anterior cruciate ligament (ACL) reconstructions in older patients. Primary ACL reconstructions using Achilles tendon allografts in patients age 30 years and older are successful in restoring the knee to “normal” or “near normal.” During a three-year period, the two senior authors performed 65 primary ACL reconstructions using Achilles tendon allografts in patients aged 30 years and older. Our exclusion criteria were periarticular fracture, ipsilateral/contralateral knee ligament injury, and previous or concomitant osteotomy or cartilage restoration procedure. Each patient was evaluated via physical examination, functional and arthrometric testing, and radiographic and subjective outcome. Knees were considered normal, near normal, or abnormal based on the International Knee Documentation Committee (IKDC) system. Forty-three patients were examined at an average of 33 months (minimum, 24 months) postoperatively. At the time of ACL reconstruction, 35% had normal articular cartilage in all three compartments and 70% had meniscal tears. No re-ruptures occurred. While 24% had mean maximal translation differences less than or equal to 3 mm, none had side-to-side differences greater than 5 mm. Postoperative IKDC, Activities of Daily Living, and Activity Rating Scale scores averaged 88, 94, and 7.7, respectively. Despite the overall favorable outcomes, 29% had worsened radiographic grades at follow-up. Using an Achilles allograft for ACL reconstruction in patients older than 30 years, we restored over 90% of knees to normal or near normal while limiting postoperative complications. Poor subjective results may be related less to instability and more to pain, which may result from progressive arthritis