A locking compression plate versus the gold-standard non-locking plate with lag screw for first metatarsophalangeal fusion: A biomechanical comparison.

INTRODUCTION: The treatment of end-stage first metatarso-phalangeal joint (MTP) arthritis has been arthrodesis. A dorsal non-locking plate with a lag screw has been the standard traditional fixation method. This study compares the biomechanical strength of a locking compression plate (LCP) with and without internal compression versus this known gold standard. METHODS: In group 1, six matched pairs of cadaver great toes were used to compare the standard non-locking dorsal plate and 3.5mm lag screw to an anatomic locking compression plate in which a lag screw was utilized rather than the internal compression features of the plate. In group 2, another six matched pairs of cadaver great toes were used to compare the gold standard to the locking compression plate, utilizing the plate's internal compression feature instead of a lag screw. A material testing system (MTS) machine applied loads to the MTP joints and measured displacement and stiffness of the constructs. The stiffness of the constructs (Young's modulus) was calculated from the force-displacement curves, and the displacement was measured. RESULTS: The locking compression plate group that used the compression features of the plate, without the lag screw, had less joint displacement and higher stiffness than control (p<0.05). The same plating construct in which a lag screw was used rather than internal compression of the plate was found to be stiffer than the control (p<0.05), but displacement was not statistically significant. DISCUSSION: The results suggest that a locking compression plate alone provides the stiffest construct for a first MTP joint fusion.

Open Reduction Internal Fixation of Posterior Malleolus Fractures and Iatrogenic Injuries: A Cadaveric Study.

Open reduction internal fixation of posterior malleolus fractures from a posterior approach is gaining popularity. One concern that has not been studied is the risk of iatrogenic injury to anatomical structures on the anterior ankle. The purpose of this study is to determine the proximity of these anterior structures with relation to K-wires advanced through the anterior cortex. A total of 10 cadaver ankles were utilized in the study. A posterolateral approach to the ankle was used. K-wires were advanced at varying levels above the articular surface, and then, the proximity of the wires to the following structures was determined: the neurovascular bundle, tibialis anterior (TA), and extensor hallucis longus. Overall, the structure most in danger of being injured was the TA (P < .001). This tendon was injured by 52% of all K-wires. These data suggest that K-wires should be advanced under direct fluoroscopic visualization to minimize the risk of iatrogenic injury. LEVELS OF EVIDENCE: Level IV.

Return to Sports and Physical Activities After the Modified Lapidus Procedure for Hallux Valgus in Young Patients.

BACKGROUND: The modified Lapidus procedure has successfully relieved pain and corrected deformity in patients with hallux valgus, but its effect on participation in specific sports and physical activities remains unclear. Our goals were to assess sports and physical activities in young patients following the modified Lapidus procedure and to compare these with clinical outcomes. METHODS: Fifty-eight eligible patients were identified from a retrospective registry review. Of these, 48 (83%) were reached for follow-up at a mean of 2.8 (range, 1.0 to 6.1) years and had a mean age at surgery of 37.3 (range, 14.1 to 49.3) years. Physical activity participation was evaluated with a new sports-specific, patient-administered questionnaire. Clinical outcomes were evaluated with the Foot and Ankle Outcome Score (FAOS) and compared to sports outcomes. RESULTS: Patients participated in 26 different physical activities, consisting of 212 total physical activities preoperatively and 209 total postoperatively. The most common were walking, running, bicycling, and swimming. Compared to preoperatively, patients rated 29% of activities as less difficult, 52% as the same, and 19% as more difficult and rated participation levels as improved in 40%, the same in 41%, and impaired in 19%. Eighty-one percent of patients were satisfied with their operative outcome in regard to return to physical activity. Changes in the FAOS Pain subscore were significantly associated with improvements in physical activity difficulty (P < .05), and changes in the Pain, Sports, and QOL subscores were significantly associated with changes in physical activity participation levels (P < .05). CONCLUSION: Four in 5 patients were able to participate in previous sports and physical activities, including high-impact activities, at their preoperative participation level or better after the modified Lapidus procedure, and were satisfied with surgery in regard to return to previous activity. However, several patients had increased difficulty and impaired participation in physical activity postoperatively. Altogether, this suggests that the procedure is a viable treatment option for hallux valgus in young, active patients. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Reduction in narcotic use after primary total knee arthroplasty and association with patient pain relief and satisfaction.

We examined the prevalence of narcotic use before and after total knee arthroplasty (TKA) and its association with post-TKA pain relief and satisfaction. Data on 6364 primary, unilateral TKA patients in a national registry were analyzed. Before TKA, 24% of patients were prescribed one form of narcotic. Of these, 14% reported continued narcotic use at 12 months after TKA, whereas the majority discontinued use. Only 3% of patients who did not use narcotics before TKA had a narcotics prescription at 12 months. Patients who used narcotics before TKA were more likely to have a narcotic prescription at 12 months post-TKA, reported greater pain at 12 months, and were more likely to be dissatisfied with TKA outcome. These findings have implications for patient pre-TKA counseling.

Detailed structural analysis of amyloidogenic wild-type transthyretin using a novel purification strategy and mass spectrometry.

Wild-type transthyretin (TTR), normally a soluble plasma-circulating protein, can be amyloidogenic, i.e., form tissue-deposited fibrillar material in the extracellular matrix of various organs throughout the body. Senile systemic amyloidosis (SSA) is one such pathology and features TTR-containing amyloid deposits that are found primarily in the heart. The cause for this transition from soluble to insoluble protein in SSA is yet to be determined as specific structural features that might favor TTR fibrillogenesis have not yet been identified. The precise characterization of ex vivo fibril deposits might provide insight, but structural analyses of TTR from amyloid deposits have been hindered thus far by the lack of purification strategies that overcome the insolubility of the tissue-derived protein without degrading it. Consequently, the true biochemical nature of deposited TTR remains in question. In this study, we provide detailed analyses of both the soluble (serum) and deposited (tissue) forms of TTR from cases of SSA. In the serum, a distribution of mixed disulfides, specifically S-sulfonated and S-cysteinylated forms of TTR, as well as the unmodified protein were identified. The relative levels of the three TTR species in the SSA group were comparable to amounts present in sera from age-matched control groups. For characterization of the amyloid deposited TTR, we investigated cardiac tissue samples obtained from three separate cases of SSA. We report a novel chromatographic purification strategy performed under nonreducing conditions (to maintain cysteine disulfide status) and the use of this procedure in conjunction with detailed mass spectrometric analysis of TTR from the amyloid deposits. A series of C-terminal TTR fragments with N-termini ranging from amino acids 46 to 55 were identified. We also determined that the deposits in all samples contained Cys10 disulfide-linkedhomodimers composed of full-length TTR monomers. This last finding suggests an important role for Cys10 conjugation in the transition from soluble TTR to the pathological amyloid fibril.