Torsional Stability of a Chevron Interface for Intercalary Allograft Fixation of the Femur

Intercalary allografts are frequently used for diaphyseal long bone reconstruction following tumor resection. Torsional stability between allograft and host bone is an important factor in achieving osseous union at the interface and reducing fracture risk of the allograft. The purpose of this study was to evaluate the torsional stability of an intercalary allograft construct using a new chevron type of osteotomy. The torsional load of up to 4.0 Nm in both directions were applied to six matching pairs of fresh frozen cadaveric femurs, reconstructed using either a 60-degree chevron or a modified step-cut interface. The torsional stiffness of the construct and the interface rotation were compared between the two groups. The results showed that a construct with a 60-degree chevron interface had comparable interface rotations and stiffness as those with the modified step-cut interface. However, the large inter-specimen variations observed in rotation results of the modified step-cut suggest higher technical requirements associated with this procedure. The study also revealed a trend towards improved torsional stiffness with increased axial load of the chevron construct, combined with its 55% more surface area across the graft-host interface over the modified step-cut, which prove that 60-degree chevron interface may serve as a good alternative in intercalary allograft fixation.

The effect of butyric acid on normal tendons: a potential stimulus for extracellular matrix expression

We propose comparing angiogenic effects of butyric acid (BA)-impregnated suture vs control suture on an aged tendon model. Twenty-four 3-year-old rabbits underwent bilateral Achilles tendon exposure. BA-impregnated orthopedic suture was sutured into one side, and a control orthopedic suture into the contralateral side similarly. The rabbits were sacrificed at 7, 30, and 45 days and the tendons harvested for gross, histologic, and biochemical study. Histologically, there was increased vascularity/cell migration at all time points in the BA-treated tendons; proteoglycan expression (ie, safranin O staining) increased at 30 and 45 days. DNA concentration was significantly (P = .05) higher in the BA-treated tendon group relative to the control group at 7 days but was unchanged at 30 and 45 days. Similarly, messenger RNA (mRNA) expression of vascular endothelial growth factor (VEGF) was significantly (P = .05) higher in the BA-treated tendon at 7 days. A trend (P = .12) for higher expression in the BA group also was found at 30 days.

Arthroscopic evaluation and management after repeated luxatio erecta of the glenohumeral joint

Luxatio erecta, inferior dislocation of the glenohumeral joint, is a relatively rare type of glenohumeral dislocation, accounting for <0.5% of all shoulder dislocations. It has been well described in terms of presentation and conservative management. Arthroscopic findings after the more commonly found anteroinferior glenohumeral dislocation have also been described. However, we know of only 1 case report that details the arthroscopic findings and open surgical management in a patient who sustained a single episode of luxatio erecta. Additionally, we were unable to find any reports in the literature of the arthroscopic management of this type of dislocation. We present the arthroscopic findings and arthroscopic management of an 18-year-old male college football player who reported 7 episodes of left shoulder luxatio erecta. Arthroscopic evaluation revealed an extensive anterior capsulolabral injury as well as a superior labrum anteroposterior (SLAP) tear. Additionally, there were extensive articular cartilage changes of the anterosuperior glenoid, a posterior Hill-Sachs lesion, and an anterosuperior humeral head cartilage indentation. The anterior capsulolabral injury and the SLAP lesion were fixed arthroscopically with suture anchors. The remainder of the lesions were debrided. The patient was able to return to college-level football and reported no further episodes of instability, pain, or stiffness at 3-year follow-up.