Biomechanical assessment of an alternative method of staple fixation for anchoring the Bone Patellar Tendon Bone graft to the tibia.

INTRODUCTION: The Anterior cruciate ligament (ACL) is the most commonly injured ligament around the knee and is best reconstructed with a biological graft. For ideal graft fixation, there should be sufficient initial strength to avoid failure of fixation and sufficient stiffness to restore the stability of the knee and to avoid gradual loosening in the post-operative period.When considering fixation of Bone Patellar Tendon Bone (BPTB) grafts to the tibia, the interference screw is considered to be the gold standard. As an alternative, we have used of staples and stainless steel (SS) wire to anchor the BPTB graft to the tibia and femur. The aim of this study was to assess the biomechanical efficacy of this fixation technique for anchoring the BPTB graft to the proximal tibia. We used a bovine model to compare three fixation techniques -interference screw, braided polyester sutures tied to a screw post and SS wire tied to a staple. MATERIALS AND METHODS: Fifteen fresh bovine knees specimens were used for the study. The patella was fixed to a load cell and the construct was pre-tensioned to 40N to allow for creep of the tendon. The BPTB graft was fixed to the tibia using the three fixation techniques - the interference screw, polyester suture tied to a post, and SS wire anchored to a staple. After fixation, the graft was subjected to a single load to failure test, and the forces generated were recorded. The ultimate failure load (the pullout strength), stiffness, and mode of failure were noted. RESULTS: In the single load-to-failure biomechanical testing, the ultimate failure load and stiffness for Staple with SS wire were 726.40N and 61.9N/mm respectively. For the screw post and polyester suture, it was 733.20N and 53.22N/mm, and for Interference screw - 594.00N and 79.50 N/mm respectively. There was no statistically significant difference in the stiffness or ultimate failure load between the three fixation techniques. The graft fixation using interference screws failed at the bone- tunnel interface by slippage of the bone block from the tunnel in all 5 specimens. In all 5 of the specimens fixed with polyester suture and the screw post, the fixation failed when the polyester suture snapped. When the SS wire and staple construct was stressed, the graft failed as the SS wire cut through the graft in 4 specimens, and in the fifth construct, the knot over the staple unraveled as the load was applied. CONCLUSION: The biomechanical properties of BPTB graft fixation with SS wire tied to a staple is similar to that of other fixation devices like the interference screw and suture post. This technique provides a simple, yet effective fixation for the graft - but needs further clinical assessment.

The inter-teres approach to glenoid neck fractures: an alternative approach to glenoid fixation.

BACKGROUND: Scapula fractures are rare injuries that are generally treated nonoperatively. When surgery is performed, it is commonly undertaken through the posterior approach, which can be invasive and unforgiving on the soft tissues. We describe an alternative safe approach between teres major and minor that remains deep to a fascial sling formed by the combined infraspinatus and teres minor fasciae and deep to the primary nerve to teres minor, which is a terminal branch of the axillary nerve. METHODS: Between January 2008 and June 2014, there were 22 patients who underwent scapula fixation with this approach who were retrospectively identified and prospectively invited for clinical review by the American Shoulder and Elbow Surgeons (ASES) evaluation form and Constant score. Postoperative external rotation (ER) power in both abduction and adduction was also assessed. RESULTS: Five patients were lost to follow-up. All of the remaining patients were male with a mean age of 44.5 years (28-66 years). Mean follow-up time was 34.7 months (3-72 months). The mean ASES score for the 17 patients was 86.6 (41.6-100); the mean Constant score was 89.3 (22-100). The only significant factor affecting the ASES score was an ipsilateral neurologic upper limb injury. ER power was improved or equivalent to the contralateral side in 8 of the 10 patients assessed for ER; it was weaker in 2 patients, both of whom had surgical fixation of the vertebral border of the scapula. CONCLUSION: The inter-teres approach may be a safe alternative approach in glenoid fixation, although the loss of ER strength needs further evaluation.

South Indian calcaneal talar facet configurations and osteoarthritic changes.

The purpose of this study was to determine the talar facet configuration of South Indian calcanei, measure the angle between the anterior and middle facet planes of these calcanei, and assess the relation between the above parameters and the degenerative changes in the subtalar joints. The angle between the anterior and middle talar facets was measured in 222 South Indian adult calcanei. The degree of sclerosis was measured on radiographs of the calcanei. Lipping and osteophytes around the joints were recorded by visual inspection. The facet patterns observed were fused anterior and middle facets (Type I), three separate facets (Type II), absence of the anterior facet (Type III), three merged facets (Type IV), and a new pattern of absent anterior and fused middle and posterior facets (Type V). An anterolateral impression was present in nine calcanei. Type I was the predominant pattern (72%). Type II configuration had the least mean angle (125 degrees) and had less number of calcanei with significant osteoarthritic changes. A wider angle was observed in Type I and Type III calcanei. Type IV and Type V were observed in only three and one calcanei, respectively. Lipping and osteophytes were observed in Type I to IV configurations. There was no correlation between the facet configuration and the radiological subchondral sclerosis in the posterior talar facet of the calcanei. This study reveals that the talar facet configuration of calcanei and the angle between the anterior and middle facets influence the stability of the subtalar joints and development of osteoarthritis.