Biomechanical comparison of pectoralis major repair techniques: A systematic review and meta-regression.

Background: There are many surgical techniques when repairing pectoralis major tears. However, there is no clear consensus on which repair technique is biomechanically superior. Our purpose was to perform a systematic review and meta-regression to evaluate the most biomechanically superior pectoralis major repair technique. Methods: We performed a systematic review and meta-regression of six human cadaveric biomechanical studies evaluating fixation techniques for pectoralis major repairs. The primary outcome was the ultimate failure load. Covariates included cadaveric age, bone mineral density, implants, suture, and stitch method. Meta-regression accounted for differences in variables. Results: Compared with Krackow/Bunnell stitch method, the modified Mason-Allen stitch demonstrated a decrease in ultimate failure load by 220.6 N (95% CI, -273.0 to -168.2; p = <0.001). No differences were found between Krackow/Bunnell and whipstitch. There was an increase in ultimate failure load when utilizing suture tape by 206.6 N (95% CI, 139.5-273.7, p < 0.001). Suture anchors had a decrease in ultimate failure load by 88.1 N (95% CI, -153.4 to -22.8, p = 0.008) when compared to transosseous sutures. No differences were found between transosseous sutures and unicortical buttons. Discussion: We found the combination of suture tape in a whipstitch or Krackow/Bunnell stitch utilizing transosseous sutures or unicortical buttons is the most biomechanically superior construct for pectoralis major repairs.

Revision Total Joint Arthroplasty Places a Disproportionate Burden on Surgeons: A Comparison Using the National Aeronautics and Space Administration Task Load Index (NASA TLX).

BACKGROUND: Perceived surgeon workload of performing primary and revision total hip arthroplasty (THA) and total knee arthroplasty (TKA) is challenging to quantify. The National Aeronautics and Space Administration Task Load Index (NASA TLX) survey was developed to quantify experiences following aviation and has been applied to healthcare fields. Our purposes were to 1) quantify the workload endured by surgeons who are performing primary and revision TKA and THA and 2) compare these values to their Center for Medicare & Medicaid Services (CMS) reimbursement. METHODS: A prospective cohort of 5 fellowship-trained adult reconstruction surgeons completed NASA TLX surveys following primary and revision TKA/THA cases. A total of 122 surveys consisting of 70 TKA (48 primaries and 22 revisions) and 55 THA surveys (38 primaries and 17 revisions) were completed. Patient demographics and surgical variables were recorded. Final NASA TLX workloads were compared to 2021 CMS work relative value units. RESULTS: Compared to primary TKA, revision TKA had 176% increased intraoperative workload (P < .001), 233% increased mental burden (P < .001), and 150% increased physical burden (P < .001). Compared to primary THA, revision THA had 106% increased intraoperative workload (P < .001), 96% increased mental burden (P < .001), and 91% increased physical burden (P < .001). Operative time was higher in revision versus primary TKA (118 versus 84.5 minutes, P = .05) and THA (150 versus 115 minutes, P = .001). Based upon 2021 CMS data, revision TKA and THA would need to be compensated by an additional 36% and 12.3%, respectively, to parallel intraoperative efforts. CONCLUSIONS: Revision hip and knee arthroplasty places a major mental and physical workload upon surgeons and is disproportionately compensated by CMS.

Actinomyces turicensis Necrotizing Soft-Tissue Infection of the Thigh in a Diabetic Male.

Background: Necrotizing soft-tissue infections are a devastating infection that is rarely caused by Actinomyces spp. Case Report: A 45-year-old obese previously healthy male presented to the emergency department with diabetic ketoacidosis. The patient developed systemic signs of infections and right medial thigh pain subsequently diagnosed as a necrotizing soft-tissue infection. Successful treatment included prompt surgical intervention and initiation of broad-spectrum antimicrobial drugs. Conclusion: Actinomyces turicensis may be the pathogen causing certain necrotizing soft-tissue infections. Clinicians should consider the possibility that this organism represents a true pathogen and not colonization/contamination.

Direct evidence of catalytic heterogeneity in lactate dehydrogenase by temperature jump infrared spectroscopy.

Protein conformational heterogeneity and dynamics are known to play an important role in enzyme catalysis, but their influence has been difficult to observe directly. We have studied the effects of heterogeneity in the catalytic reaction of pig heart lactate dehydrogenase using isotope edited infrared spectroscopy, laser-induced temperature jump relaxation, and kinetic modeling. The isotope edited infrared spectrum reveals the presence of multiple reactive conformations of pyruvate bound to the enzyme, with three major reactive populations having substrate C2 carbonyl stretches at 1686, 1679, and 1674 cm(-1), respectively. The temperature jump relaxation measurements and kinetic modeling indicate that these substates form a heterogeneous branched reaction pathway, and each substate catalyzes the conversion of pyruvate to lactate with a different rate. Furthermore, the rate of hydride transfer is inversely correlated with the frequency of the C2 carbonyl stretch (the rate increases as the frequency decreases), consistent with the relationship between the frequency of this mode and the polarization of the bond, which determines its reactivity toward hydride transfer. The enzyme does not appear to be optimized to use the fastest pathway preferentially but rather accesses multiple pathways in a search process that often selects slower ones. These results provide further support for a dynamic view of enzyme catalysis where the role of the enzyme is not just to bring reactants together but also to guide the conformational search for chemically competent interactions.