A regenerative peripheral nerve interface allows real-time control of an artificial hand in upper limb amputees.

Peripheral nerves provide a promising source of motor control signals for neuroprosthetic devices. Unfortunately, the clinical utility of current peripheral nerve interfaces is limited by signal amplitude and stability. Here, we showed that the regenerative peripheral nerve interface (RPNI) serves as a biologically stable bioamplifier of efferent motor action potentials with long-term stability in upper limb amputees. Ultrasound assessments of RPNIs revealed prominent contractions during phantom finger flexion, confirming functional reinnervation of the RPNIs in two patients. The RPNIs in two additional patients produced electromyography signals with large signal-to-noise ratios. Using these RPNI signals, subjects successfully controlled a hand prosthesis in real-time up to 300 days without control algorithm recalibration. RPNIs show potential in enhancing prosthesis control for people with upper limb loss.

Elevation in circulating biomarkers of cartilage damage and inflammation in athletes with femoroacetabular impingement.

BACKGROUND: Femoroacetabular impingement (FAI) is one of the most common causes of early cartilage and labral damage in the nondysplastic hip. Biomarkers of cartilage degradation and inflammation are associated with osteoarthritis. It was not known whether patients with FAI have elevated levels of biomarkers of cartilage degradation and inflammation. HYPOTHESIS: Compared with athletes without FAI, athletes with FAI would have elevated levels of the inflammatory C-reactive protein (CRP) and cartilage oligomeric matrix protein (COMP), a cartilage degradation marker. STUDY DESIGN: Controlled laboratory study. METHODS: Male athletes with radiographically confirmed FAI (n = 10) were compared with male athletes with radiographically normal hips with no evidence of FAI or hip dysplasia (n = 19). Plasma levels of COMP and CRP were measured, and subjects also completed the Short Form-12 (SF-12) and Hip Disability and Osteoarthritis Outcome Score (HOOS) surveys. RESULTS: Compared with controls, athletes with FAI had a 24% increase in COMP levels and a 276% increase in CRP levels as well as a 22% decrease in SF-12 physical component scores and decreases in all of the HOOS subscale scores. CONCLUSION: Athletes with FAI demonstrate early biochemical signs of increased cartilage turnover and systemic inflammation. CLINICAL RELEVANCE: Chondral injury secondary to the repetitive microtrauma of FAI might be reliably detected with biomarkers. In the future, these biomarkers might be used as screening tools to identify at-risk patients and assess the efficacy of therapeutic interventions such as hip preservation surgery in altering the natural history and progression to osteoarthritis.

Accuracy of medial foot compartment pressure testing: a comparison of two techniques.

BACKGROUND: Foot compartment syndrome is diagnosed with intracompartmental pressure measurements. The purpose of this study was to determine the ability of two techniques to accurately place a needle tip within the medial foot compartment and to compare the proximity of the needle tip to the medial foot compartment neurovascular structures between the two techniques. MATERIALS AND METHODS: This was a laboratory study using ten unembalmed cadaveric ankle-foot specimens. Two 18-gauge side-ported needles were placed into the medial foot compartments of each cadaveric specimen utilizing two separate techniques (Mollica and Reach techniques). Ultrasound was used to confirm needle tip placement within the medial foot compartment and needle proximity to the neurovascular structures. RESULTS: Both needle placement techniques accurately placed the needle tip within the medial foot compartment. However, the distance between the needle tip and the neurovascular structures of the medial foot compartment was significantly closer (p = 0.037) using the Mollica technique (mean = 3.9 mm ± 2.2 mm) than the Reach technique (mean = 10.9 mm ± 5.2 mm). Neither needle placement technique perforated the medial foot neurovascular structures. CONCLUSION: While both medial foot compartment pressure techniques accurately placed the needle tip within the medial foot compartment, the needle tip was significantly further from the medial foot neurovascular structures using the Reach technique than the Mollica technique. The Reach technique involves inserting the needle 6 cm below the distal tip of the medial malleolus, and advancing it 1 cm in a medial to lateral direction.