RESUMO
PURPOSE: Fresh-frozen specimen availability and cost may be a barrier for initiation of biomechanical studies where soft tissue is used in a construct with other medical devices. The impact of soft tissue preservation method on the outcomes of biomechanical studies in the specific case of graft-suture constructs is relatively unexplored. This study aimed to observe peak loads and failure modes in biomechanical testing of fresh-frozen (FF) versus formalin embalmed (FE) quadriceps tendon (QT) graft-suture constructs for soft tissue fixation in ACLR and assess suitability of FE QT graft constructs for load-to-fail testing. METHODS: Twenty QT grafts were harvested from human cadaver specimens. Ten grafts came from fresh-frozen donors and 10 from embalmed donors. All grafts were prepared with the modified Prusik knot using a braided composite suture and subjected to tensile loading. Comparisons between the biomechanical properties of the graft-suture constructs were made with unpaired t tests with α = 0.05. RESULTS: FE and FF constructs displayed similar peak loads and failure modes. FF constructs had greater elongation after pre-tensioning than FE (7.3 vs. 5.5 mm, p = 0.02) and greater elongation after cyclic loading than FE constructs (17.5 vs. 10.5 mm, p = 0.01). Hysteresis was greater for FF constructs at the 50th, 100th, 150th, and 200th cycle (p = 0.02, p = 0.07, p < 0.001, p = 0.004, respectively). FE constructs were stiffer than fresh-frozen (103 vs. 84 N/mm, p < 0.001). CONCLUSION: FE constructs were significantly stiffer but displayed similar peak load and failure mode to FF which was reflective of the strength of the suture material. FE grafts can offer an alternative to FF grafts in graft-suture constructs for biomechanical studies where load at failure and knot security and strength is of main interest.
RESUMO
There is currently a lack of information available about the effect that exercise fatigue may have on Child Sport Concussion Assessment Tool (SCAT) scoring in a pediatric population. Objective: The goal of this study was to examine the influence of a fatiguing bout of aerobic exercise on Child Sport Concussion Assessment Tool (SCAT) scoring in an adolescent female sporting population. Methods: A prospective, observational-based, test-retest study design was used to collect Child SCAT data from thirty healthy 9-12 year old physically active females during two testing sessions that occurred a minimum of 7 days apart. Within each testing session, each child completed a fatiguing bout of aerobic exercise, and the Child SCAT was administered: (1). Pre-exercise and (2). Post-exercise. Parametric and non-parametric testing was used to compare aerobic exercise test results and pre- vs. post-exercise Child SCAT data. Test-retest reliability was evaluated using intra-class correlation coefficient (ICC 3,1) analysis. Results: No significantly differences were noted between pre- and post-exercise Child SCAT data during either test day. ICC values suggested that a majority of the individual components of the Child SCAT demonstrated poor test-retest reliability. Conclusion: Clinicians using the Child SCAT as a sideline assessment tool during youth sport should have confidence that individual component scores are uninfluenced by aerobic exercise completed immediately prior to assessment. But, clinicians should also be cautioned against using Child SCAT data from consecutive testing days when making decisions about patient recovery and return-to-sport timelines.