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We conducted a systematic review of studies reporting clinical outcomes after proximal row carpectomy or to four-corner arthrodesis for scaphoid non-union advanced collapse or scapholunate advanced collapse arthritis. Seven studies (Levels I-III; 240 patients, 242 wrists) were evaluated. Significantly different post-operative values were as follows for four-corner arthrodesis versus proximal row carpectomy groups: wrist extension, 39 (SD 11º) versus 43 (SD 11º); wrist flexion, 32 (SD 10º) versus 36 (SD 11º); flexion-extension arc, 62 (SD 14º) versus 75 (SD 10º); radial deviation, 14 (SD 5º) versus 10 (SD 5º); hand grip strength as a percentage of contralateral side, 74% (SD 13) versus 67% (SD 16); overall complication rate, 29% versus 14%. The most common post-operative complications were non-union (grouped incidence, 7%) after four-corner arthrodesis and synovitis and clinically significant oedema (3.1%) after proximal row carpectomy. Radial deviation and post-operative hand grip strength (as a percentage of the contralateral side) were significantly better after four-corner arthrodesis. Four-corner arthrodesis gave significantly greater post-operative radial deviation and grip strength as a percentage of the opposite side. Wrist flexion, extension, and the flexion-extension arc were better after proximal row carpectomy, which also had a lower overall complication rate.

Background:The biomechanical effects of lateral meniscal posterior root tears with and without meniscofemoral ligament (MFL) tears in anterior cruciate ligament (ACL)–deficient knees have not been studied in detail.Purpose:To determine the biomechanical effects of the lateral meniscus (LM) posterior root tear in ACL-intact and ACL-deficient knees. In addition, the biomechanical effects of disrupting the MFLs in ACL-deficient knees with meniscal root tears were evaluated.Study Design:Controlled laboratory study.Methods:Ten paired cadaveric knees were mounted in a 6-degrees-of-freedom robot for testing and divided into 2 groups. The sectioning order for group 1 was (1) ACL, (2) LM posterior root, and (3) MFLs, and the order for group 2 was (1) LM posterior root, (2) ACL, and (3) MFLs. For each cutting state, displacements and rotations of the tibia were measured and compared with the intact state after a simulated pivot-shift test (5-N·m internal rotation torque combined with a 10-N·m valgus torque) at 0°, 20°, 30°, 60°, and 90° of knee flexion; an anterior translation load (88 N) at 0°, 30°, 60°, and 90° of knee flexion; and internal rotation (5 N·m) at 0°, 30°, 60°, 75°, and 90°.Results:Cutting the LM root and MFLs significantly increased anterior tibial translation (ATT) during a pivot-shift test at 20° and 30° when compared with the ACL-cut state (both Ps < .05). During a 5-N·m internal rotation torque, cutting the LM root in ACL-intact knees significantly increased internal rotation by between 0.7° ± 0.3° and 1.3° ± 0.9° (all Ps < .05) except at 0° (P = .136). When the ACL + LM root cut state was compared with the ACL-cut state, the increase in internal rotation was significant at greater flexion angles of 75° and 90° (both Ps < .05) but not between 0°and 60° (all Ps > .2). For an anterior translation load, cutting the LM root in ACL-deficient knees significantly increased ATT only at 30° (P = .007).Conclusion:The LM posterior root was a significant stabilizer of the knee for ATT during a pivot-shift test at lower flexion angles and internal rotation at higher flexion angles.Clinical Relevance:Increased knee anterior translation and rotatory instability due to posterior lateral meniscal root disruption may contribute to increased loads on an ACL reconstruction graft. It is recommended that lateral meniscal root tears be repaired at the same time as an ACL reconstruction to prevent possible ACL graft overload.

Multiple factors alter intervertebral disc volume, structure, shape, composition, and biomechanical properties, often leading to low back pain. Spinal fusion is frequently performed to treat this problem. We recently published results of our investigation of a novel system of in vivo bone formation, in which we used nonvirally nucleofected human mesenchymal stem cells that overexpress a bone morphogenetic protein gene. We hypothesized that primary porcine adipose tissue-derived stem cells (ASCs) nucleofected with plasmid containing recombinant human bone morphogenetic protein-6 (rhBMP-6) could induce bone formation and achieve spinal fusion in vivo. Primary ASCs were isolated from freshly harvested porcine adipose tissue. Overexpression of rhBMP-6 was achieved ex vivo by using a nucleofection technique. Transfection efficiency was monitored by assessing a parallel transfection involving an enhanced green fluorescent protein reporter gene and flow cytometry analysis. rhBMP-6 protein secreted by the cells was measured by performing an enzyme-linked immunosorbent assay. Genetically engineered cells were injected into the lumbar paravertebral muscle in immunodeficient mice. In vivo bone formation was monitored by a quantitative microcomputed tomography (CT). The animals were euthanized 5 weeks postinjection, and spinal fusion was evaluated using in vitro CT and histological analysis. We found formation of a large bone mass adjacent to the lumbar area, which produced posterior spinal fusion of two to four vertebrae. Our data demonstrate that efficient bone formation and spinal fusion can be achieved using ex vivo, nonvirally transfected primary ASCs. These results could pave the way to a novel biological solution for spine treatment. STEM CELLS

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