We reviewed the results in 13 patients who underwent simultaneous allograft reconstruction of both the anterior and posterior cruciate ligaments after a knee dislocation (nine acute and four chronic injuries). Seven patients sustained related medial collateral ligament injuries and six patients had posterolateral complex injuries. Ligament reconstructions were performed using fresh-frozen Achilles or patellar tendon allografts. At follow-up evaluation (mean of 38 months), only one patient described the reconstructed knee as normal. Six patients had returned to unrestricted sports activities and four had returned to modified sports. The average extension loss was 3 degrees (range, 0 degree to 10 degrees) and average flexion loss was 5 degrees (range, 0 degree to 15 degrees). The KT-1000 arthrometer measurements at 133 N anterior-posterior tibial load showed a mean side-to-side difference of 4.5 mm (range, 0 to 10) at 20 degrees and 5.0 mm (range, 0 to 9) at 70 degrees. The mean Lysholm score was 88 (range, 42 to 100). International Knee Documentation Committee ratings were six nearly normal, five abnormal, and one grossly abnormal. Two patients required manipulations for knee stiffness. This study demonstrates that reconstruction of both cruciate ligaments can restore stability sufficient to allow sports activity in most patients with knee dislocations, but "normal" results are difficult to achieve.

Over 50% of all knee injuries involve partial or complete tear of the anterior cruciate ligament. Surgical reconstruction of this ligament using an isometrically placed bone-patellar tendon-bone autograft is the current technique of choice; however, harvest of patellar tendon as a free graft can lead to increased morbidity. To address this issue, allogenic patellar tendon grafts have been introduced as alternatives to autogenic graft material. The purpose of this study was to examine effects of age and strain rate on tensile strength, modulus, and failure mode of bone-patellar tendon-bone allografts from a typical population of tissue donors. Eighty-two, fresh-frozen, bone-patellar tendon-bone allografts were harvested from 25 different donors, aged 17 to 54. Paired grafts from individual patellar tendons were assigned randomly to tensile testing at either 10% or 100% elongation per second. Tensile strength, modulus, and failure mode were not significantly different for tests conducted at these 2 strain rates. Correlations between tensile strength and age were not significant for tests conducted at either strain rate. Specimens tested at a strain rate of 100% per second exhibited weak but significant negative correlation between modulus and age, with modulus decreasing 25% over the age range examined.

Augmentation is a well-accepted and common component of coracoclavicular ligament repairs and reconstructions. The purpose of this study was to examine and compare the strength, stiffness, and mode of failure of the coracoclavicular ligament complex and four different augmentation techniques in cadaveric shoulders. There was no significant difference in the mean failure load between the intact ligament complex (724.9+/-230.9 N) and augmentations performed with braided polydioxanone (PDS) (676.7+/-115.4 N) or braided polyethylene placed through (986.1+/-391.1 N) or around (762.7+/-218.2 N) the clavicle. The mean failure load for augmentations using a 6.5-mm cancellous screw through the clavicle and into a single cortex of the coracoid (390.1+/-253.6 N) was significantly lower than that for the intact coracoclavicular ligaments. There was no difference in mean stiffness between the intact coracoclavicular ligament complex (115.9+/-36.2 N/mm) and the braided polyethylene augmentations placed through (99.8+/-22.2 N/mm) or around (90.0+/-25.5 N/mm) the clavicle. Polydioxanone augmentations were significantly less stiff (27.4+/-3.3 N/mm) than the intact complex, while screw augmentations were significantly stiffer (250.4+/-88.2 N/mm). There were no significant differences in strength or stiffness of braided polyethylene reconstructions placed around or through a drill hole in the clavicle.

The muscle-fiber architecture of 29 muscles from six rabbits (Oryctolagus cuniculus) was measured in order to describe the muscular properties of this cursorial animal, which possesses several specific skeletal adaptations. Several muscles were placed into one of four functional groups: hamstrings, quadriceps, dorsiflexors, or plantarflexors, for statistical comparison of properties between groups. Antagonistic groups (i.e., hamstrings vs. quadriceps or dorsiflexors vs. plantarflexors) demonstrated significant differences in fiber length, fiber length/muscle length ratio, muscle mass, pinnation angle, and number of sarcomeres in series (P less than .02). Discriminant analysis permitted characterization of the "typical" muscle belonging to one of the four groups. The quadriceps were characterized by their large pinnation angles and low fiber length/mass ratios, suggesting a design for force production. Conversely, the hamstrings, with small pinnation angles, appeared to be designed to permit large excursions. Similar differences were observed between plantarflexors and dorsiflexors, which have architectural features that suit them for force production and excursion respectively. Although these differences were not absolute, they represented clear morphological distinctions that have functional consequences.

No abstract