A Retrospective Comparative Analysis of the Use of Implantable Bone Stimulators in Nonunions.

This study details the use of implantable bone stimulators in the setting of nonunion. A retrospective comparative analysis was used to evaluate the efficacy of implantable bone stimulators in achieving union in the setting of atrophic or oligotrophic nonunion by two fellowship-trained orthopaedic trauma surgeons. Initially, 72 patients underwent surgical intervention for nonunion. Twenty-one patients had an implantable bone stimulator placed at the time of nonunion surgery. Thirty-eight patients had a minimum of 1-year follow-up. An implantable bone stimulator was used in 13 patients and 25 patients did not have a bone stimulator. The use of implantable bone stimulators was found to be significantly associated with increased union rates (p = .042). (Journal of Surgical Orthopaedic Advances.

Primary total knee arthroplasty in a patient with a chronic extensor mechanism deficiency.

A 44-year-old female presented with a chief complaint of left knee pain and dysfunction. The patient had a complex surgical history including patellar fracture repair, subsequent patellar ligament repair, and ultimately allograft reconstruction which was complicated by septic arthritis requiring graft resection. On presentation to our clinic, she was noted to have significant degenerative disease in addition to chronic extensor mechanism deficiency. She underwent primary total knee arthroplasty with concomitant tibial tubercle osteotomy and advancement. The patient has had an excellent result postoperatively including return of full range of motion without residual extensor lag.

Variations in the fibre repeat between samples of cellulose I from different sources.

A powder X-ray diffractometer was used to measure the fibre repeat in cellulose I with sufficient precision to detect variations between samples from different sources. The variations were correlated with the lateral dimensions of the crystallites and were attributed to different minimum-energy fibre repeats for chains in the interiors and on the surfaces of crystallites. Results were interpreted in terms of a model for internal mechanical stress in which the interior chains were under compression and the surface chains under tension to ensure identical fibre repeats for all chains. The model was used to extrapolate the fibre repeat to a value of 1.043 nm for a hypothetical, infinitely large crystal, and to 1.029 nm for a crystallite so narrow that all chains were exposed on surfaces.