A Multidisciplinary Study of the Healing of an Intraarticular Anterior Cruciate Ligament Graft in a Goat Model

Abstract

We evaluated knee function, tensile properties, and histologic appearance of a healing intraarticular bone-patellar tendon-bone autograft after anterior cruciate ligament reconstruction in a goat model. The patellar tendon graft was fixed such that both bone-to-bone (femoral tunnel) and bone-to-tendon (tibial tunnel) healing could be studied. The total anteroposterior translation significantly increased from 3 to 6 weeks, ranging from increases of 28.8% to 46.7%. In situ forces in the replacement graft decreased as much as 22.2% at 6 weeks. Conversely, tensile properties of the femur-anterior cruciate ligament graft-tibia complex did not change significantly from 3 to 6 weeks. However, the mode of failure changed from the graft pulling out of the tibial tunnel at 3 weeks to a mix of midsubstance failures (N = 2) and pullouts (N = 5) at 6 weeks. Histologic evaluations revealed progressive and complete incorporation of the bone block in the femoral tunnel, but only partial incorporation of the tendinous part of the graft in the tibial tunnel. The differences demonstrated at 3 and 6 weeks may be a result of the remodeling process of the midsubstance of the graft as the interfaces within the osseous tunnels mature.

The effect of initial graft tension on the biomechanical properties of a healing ACL replacement graft: A study in goats

“…44.3 & 6.2 kg; mean& SD) were used for this study. The goat was chosen for this study because, unlike the canine and rabbit models, ACL reconstructions have been deemed successful out to three years with very low rates of graft failures or severe articular cartilage degeneration [23,33,34]. All goats were required to pass a veterinary examimtion to rule out any physical or physiological abnormalities prior to testing.…”

“…anterior posterior (A-P) translations, internal-external and varus viilgus rotations) joint motions are measured [22,34,39]. By repeating these positions with a high level of accuracy, the principle of super- position can be applied, allowing the in situ forces in the ligament to be determined [17,18,38].…”

“…Issues including the contribution of muscles to joint stability, swelling of soft tissues, and a lack of standardized techniques to evaluate the ACL graft's contribution to joint function have clouded the ability for researchers to quantitatively assess the effects of initial graft tension during the early healing process. As the graft will undergo changes during the early stages of healing [20,33,34,37,47], it is important to know how the effects of initial graft tension change with time. A multiple time point study that quantitatively examines the ACL graft's contribution to knee kinematics as function of initial graft tension will help to delineate the relationship between initial graft tension and the remodeling process of the ACL graft.…”

Comparison of tunnel widening between interference screw and suture disc fixation after ACL reconstruction using CT scan

“…Graft fixation is the weak link of the construct until histological anchoring of the graft in the bone tunnel occurs. 23,24 In animal models, it appears that grafts with bone plugs (6 weeks) achieve histological incorporation earlier than soft tissue grafts (4 months). 25 Wieler et al showed in animal studies that reducing the relative motion between tendon and wall of the tunnel promotes the ingrowth of an intervening fibrous layer and bony trabeculae.…”

Integración tendinosa de plastias autólogas en túneles de diferente calibre. Estudio experimental en ovejas

“…El injerto presenta una pérdida lenta de sus propiedades mecánicas en la fase inicial que dura hasta la 6ª semana [35] [192][216] pero nunca llegan a alcanzar valores de normalidad. Esto nos plantea una duda sobre la eficacia mecánica de las cirugías de reconstrucción del LCA.…”