Evaluation of a novel biomaterial for intrasubstance muscle laceration repair.

The authors compare the effects of small intestinal submucosa (SIS) treatment to suture repair with respect to histologic and functional outcomes for complete muscle lacerations in a rabbit model. The authors hypothesized that SIS treatment of full-thickness muscle belly lacerations would significantly improve muscle function, strength, and regeneration compared to the current standard-of-care treatment. Muscle belly lacerations were created in the extensor digitorum longus (EDL) of both hind limbs of each rabbit. After randomization, lacerations were left unrepaired (n = 48) or repaired using a 4-0 Prolene modified Kessler stitch (n = 48). A flap of SIS graft was sutured into half (n = 24 each) of the repaired and unrepaired muscles forming four study groups. Suture repair with SIS augmentation of complete muscle lacerations resulted in healed tissue that most closely resembled normal muscle in terms of morphology and function when compared to current standard-of-care treatments. Active force production in this group reached 79% of uninjured controls 12 weeks after surgery. SIS may have important clinical advantages over suture repair alone and warrants further clinical study.

Can high-flexion tibial inserts improve range of motion after posterior cruciate-retaining total knee arthroplasty?

Interest in high-flexion total knee arthroplasty (TKA) prostheses designed to provide better postoperative range of motion (ROM) is widespread. We sought to determine whether changes in surface geometry of the tibial polyethylene insert could improve postoperative ROM in a consecutive series of patients undergoing TKA with retention of the posterior cruciate ligament (PCL). Two cohorts with Smith & Nephew (Memphis, Tennessee) Posterior Cruciate-Retaining Genesis II total knee prostheses were compared, 79 knees (65 patients) using standard tibial inserts and 85 knees (72 patients) using high-flexion inserts. The standard insert has a slightly raised posterior lip, whereas the high-flexion insert is recessed downward at the posterior margin to facilitate femoral rollback in flexion and eliminate impingement of the femoral component on the back of the polyethylene during rollback. Mean ROM 1 year postoperatively was 112.0° in patients receiving the standard insert and 119.3° in patients receiving the high-flexion insert. Preoperative ROM was similar in both groups. Flexion improvement in the high-flexion group over the standard insert group was statistically significant (P<.001). Final Knee Society Scores did not differ amongst patients receiving the standard and high-flexion inserts. Our study demonstrates that improved postoperative flexion can be achieved without changing surgical technique, bony cuts, or metallic prosthetic parts. This is the first report that we are aware of that documents improvement in ROM after PCL-retaining TKA through the use of high-flexion inserts.

Clinical results of minimal screw plate fixation of forearm fractures.

Traditional plating technique for forearm fractures specifies implant selection based on achieving a minimum number of "cortices" of screw fixation on either side of the fracture. Recent biomechanical data suggest that plates with fewer screws provide equivalent strength of fixation compared with standard compression plating techniques in forearm fractures. As described in this article, we retrospectively reviewed a surgeon's experience at a regional level I trauma center to evaluate the clinical outcome of this newer fixation strategy. Seventy-eight fractured bones were plated using "minimal" screw technique--less than the traditionally recommended 6 cortices of screw purchase. Nonunion or fixation failure occurred in 7 fractures (5 patients), producing a union rate of 91% (71/78). All nonunions were atrophic and occurred in open fractures with bone loss. No construct failed because of fixation loss caused by having too few screws. Minimal screw plate technique was stable fixation, despite not having 6 cortices on both sides of the fracture. Technical emphasis should be on adequate plate length rather than number of cortices of fixation in each segment.