Preventing and Treating Infection in Reverse Total Shoulder Arthroplasty.

PURPOSE OF REVIEW: Periprosthetic infection after shoulder arthroplasty is relatively uncommon though associated with severe long-term morbidity when encountered. The purpose of the review is to summarize the recent literature regarding the definition, clinical evaluation, prevention, and management of prosthetic joint infection after reverse shoulder arthroplasty. RECENT FINDINGS: The landmark report generated at the 2018 International Consensus Meeting on Musculoskeletal Infection has provided a framework for diagnosis, prevention, and management of periprosthetic infections after shoulder arthroplasty. Shoulder specific literature with validated interventions to reduce prosthetic joint infection is limited; however existing literature from retrospective studies and from total hip and knee arthroplasty allows us to make relative guidelines. One and two-stage revisions seem to demonstrate similar outcomes; however, no controlled comparative studies exist limiting the ability to make definitive recommendations between the two options. We report on recent literature regarding the current diagnostic, preventative, and treatment options for periprosthetic infection after shoulder arthroplasty. Much of the literature does not distinguish between anatomic and reverse shoulder arthroplasty, and further high-level shoulder specific studies are needed to answer questions generated from this review.

Using Wearable Technology to Measure the Association Between Neck Posture and Pain During Urologic Open and Robotic Surgery.

Purpose: Chronic neck pain is the most prevalent work-related musculoskeletal injury among surgeons. Urologists may be at higher risk of neck injury due to extended time spent operating in deep anatomical structures during open surgery. Our goal was to use wearable technology to quantify the relationship between neck posture and pain during open and robotic surgery. Materials and Methods: Urologic attendings and residents who spent at least 1 day per week performing surgery for >6 hours took part in this study. Neck posture was measured in real time during surgery using inertial measurement devices attached at the occipital protuberance and seventh cervical vertebrae. Self-reported neck pain scores were obtained throughout their workday. Results: Thirty participants and 202 hours of surgery were included in the study (21 attendings, 9 residents). There was a significant association between neck posture and pain (p = 0.04). Surgeons performing open procedures spent on average 147 minutes with their head in neck flexion postures of 30° or greater compared with 68 minutes for those performing robotic procedures (p = 0.007). Surgeons performing open procedures reported a mean change in neck pain of 2.0 on the numeric analogue scale, compared with 1.3 for those performing robotic procedures (p = 0.04). Conclusions: Real-time measurements of neck flexion during urologic surgery shows that greater duration and higher degree of neck flexion were associated with increased neck pain. Raising awareness about ergonomics in the operating room during residency will enable future generations of surgeons to make conscious decisions regarding their neck posture in surgery.

Biomechanical Effects of Blood Flow Restriction Training after ACL Reconstruction.

INTRODUCTION: After anterior cruciate ligament reconstruction surgery, returning the knee to previous levels of strength and function is challenging, with the failure to do so associated with an increased risk of reinjury and long-term degenerative problems. Blood flow restriction (BFR) is gaining popularity as a rehabilitation technique; however, its effects on the mechanics of these exercises have not been fully explored. In this study, we aimed to determine the acute effects of BFR on the performance of a step-up exercise protocol and to assess the acceptability of the technique. METHODS: Twenty individuals (12 female/8 male; mean age, 30.6 yr) who had recently undergone anterior cruciate ligament reconstruction and 20 controls (11 female/9 male, mean age 28.0 yr) performed a step-up exercise protocol with and without BFR. Lower limb kinematics and kinetics were measured and compared between groups and conditions. Testing was completed in June 2019. RESULTS: Participants in both groups had increased external rotation of the tibia of 2° (P < 0.001) and reductions in knee flexion and rotation torques around the joint of around 50% (P < 0.001) when using BFR compared with nonrestricted step-up exercise. The intervention was found to increase the difficulty of the exercise and induce moderate levels of discomfort (P < 0.001). CONCLUSION: The present study provides cautious support for the use of BFR, showing that there are minimal changes in knee joint mechanics when performing the same exercise without BFR, and that the changes do not increase joint torques at the knee. From an acute biomechanical perspective, the intervention appears safe to use under qualified supervision; however, effects of repetitive use and long-term outcomes should be monitored.

Monitoring changes in knee surface morphology after anterior cruciate ligament reconstruction surgery using 3Dsurface scanning.

STUDY DESIGN: Prospective case series. BACKGROUND: After surgical reconstruction of the anterior cruciate ligament, recovery to pre-injury levels of knee function is challenging. Postoperative edema and muscle atrophy are common roadblocks to full function and are evident in changes to the surface morphology of the knee. There are currently few accessible objective tools to accurately track these morphological changes. OBJECTIVES: We aimed to determine if 3D surface scanning can be used to monitor changes in the external shape of the knee after surgery and throughout the rehabilitation process. METHODS: Thirty participants had 3D surface scans taken of their knee, along with questionnaire-based functional outcomes prior to surgery (baseline), and at two-week, six-week, 12-week, and 26-week timepoints post-surgery. Volumetric changes relative to pre-op were assessed using generalized linear growth models for key anatomical regions and correlated with functional outcomes. RESULTS: Significant swelling of the patella region compared to baseline was evident immediately after surgery (14%, p < 0.001), before returning to pre-operative levels. Changes in volume at this region were significantly associated with patient-reported functional outcomes. Reductions in volume of the regions corresponding to the vastus medialis and lateralis muscles were significant at 12 weeks post-surgery (p = 0.018 and 0.01 respectively) but returned to baseline levels at six months. CONCLUSION: We demonstrate the use of 3D surface scanning as a method for capturing detailed measurements of knee surface morphology after surgery. Significant changes in external morphology are evident during the rehabilitation process.

Plantar pressures in identical and non-identical twins.

Identifying environmental risk factors for musculoskeletal disorders is challenging due to the number of potential confounders. Twins are of particular interest for researchers interested in studying these types of problems due to their inherent control for the influence of genetic factors. In twin studies, this population can allow environmental risk factors to be more easily identified, and this type of study design may allow the role of biomechanics in injury and disease to be further explored. At present, it is unclear if foot function displays more similarity between certain types of twins. In this study, we hypothesized that the plantar pressures of monozygotic (identical) twins would be more similar between pairs than dizygotic (non-identical) twins. We measured static and dynamic plantar pressures from five pairs of each twin type. Statistical parametric modeling was used to compare pressure distributions at the sensor level. For >80% of stance phase, the pixel level analysis indicated that monozygotic twins had less variation in plantar pressure between pairs. The average z-statistic across the entire trial was 0.88 for the monozygotic group and 1.13 for the dizygotic group. In this study we provide evidence of greater similarity of plantar pressures in monozygotic twin pairs compared to dizygotic twins. This finding supports the use of co-twin studies investigating potentially modifiable environmental and biomechanical risk factors for musculoskeletal conditions that affect the foot and ankle.