Disability-adjusted life years from bone and joint infections associated with antimicrobial resistance: an insight from the 2019 Global Burden of Disease Study.

PURPOSE: Bone and joint infections, complicated by the burgeoning challenge of antimicrobial resistance (AMR), pose significant public health threats by amplifying the disease burden globally. We leveraged results from the 2019 Global Burden of Disease Study (GBD) to explore the impact of AMR attributed to bone and joint infections in terms of disability-adjusted life years (DALYs), elucidating the contemporary status and temporal trends. METHODS: Utilizing GBD 2019 data, we summarized the burden of bone and joint infections attributed to AMR across 195 countries and territories in the 30 years from 1990 to 2019. We review the epidemiology of AMR in terms of age-standardized rates, the estimated DALYs, comprising years of life lost (YLLs) and years lived with disability (YLDs), as well as associations between DALYs and socio-demographic indices. RESULTS: The GBD revealed that DALYs attributed to bone and joint infections associated with AMR have risen discernibly between 1990 and 2019 globally. Significant geographical disparities and a positive correlation with socio-demographic indicators were observed. Staphylococcus aureus infections, Group A Streptococcus, Group B Streptococcus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Enterobacter-related bone and joint infections were associated with the highest DALYs because of a high proportion of antimicrobial resistance. Countries with limited access to healthcare, suboptimal sanitary conditions, and inconsistent antibiotic stewardship were markedly impacted. CONCLUSIONS: The GBD underscores the escalating burden of bone and joint infections exacerbated by AMR, necessitating urgent, multi-faceted interventions. Strategies to mitigate the progression and impact of AMR should emphasize prudent antimicrobial usage and robust infection prevention and control measures, coupled with advancements in diagnostic and therapeutic modalities.

A critical role for erythropoietin on vagus nerve Schwann cells in intestinal motility.

BACKGROUND: Dysmotility and postoperative ileus (POI) are frequent major clinical problems post-abdominal surgery. Erythropoietin (EPO) is a multifunctional tissue-protective cytokine that promotes recovery of the intestine in various injury models. While EPO receptors (EPOR) are present in vagal Schwann cells, the role of EPOR in POI recovery is unknown because of the lack of EPOR antagonists or Schwann-cell specific EPOR knockout animals. This study was designed to explore the effect of EPO via EPOR in vagal nerve Schwann cells in a mouse model of POI. RESULTS: The structural features of EPOR and its activation by EPO-mediated dimerization were understood using structural analysis. Later, using the Cre-loxP system, we developed a myelin protein zero (Mpz) promoter-driven knockout mouse model of Schwann cell EPOR (MpzCre-EPORflox/flox / Mpz-EPOR-KO) confirmed using PCR and qRT-PCR techniques. We then measured the intestinal transit time (ITT) at baseline and after induction of POI with and without EPO treatment. Although we have previously shown that EPO accelerates functional recovery in POI in wild type mice, EPO treatment did not improve functional recovery of ITT in POI of Mpz-EPOR-KO mice. CONCLUSIONS: To the best of our knowledge, this is the first pre-clinical study to demonstrate a novel mouse model of EPOR specific knock out on Schwan cells with an effect in the gut. We also showed novel beneficial effects of EPO through vagus nerve Schwann cell-EPOR in intestinal dysmotility. Our findings suggest that EPO-EPOR signaling in the vagus nerve after POI is important for the functional recovery of ITT.

Effects of 4-Aminopyridine on Combined Nerve and Muscle Injury and Bone Loss.

PURPOSE: Musculoskeletal injuries are common, and peripheral nerve injury (PNI) causes significant muscle and bone loss within weeks. After PNI, 4-aminopyridine (4-AP) improves functional recovery and muscle atrophy. However, it is unknown whether 4-AP has any effect on isolated traumatic muscle injury and PNI-induced bone loss. METHODS: A standardized crush injury was performed on the sciatic nerve and muscles in mice, and the mice were assigned to receive normal saline or 4-AP treatment daily for 21 days. The postinjury motor and sensory function recovery was assessed, injured muscles were processed for histomorphometry, and the tibial bone was scanned for bone density. RESULTS: 4-Aminopyridine significantly accelerated the postinjury motor and sensory function recovery, improved muscle histomorphometry, increased muscle satellite cell numbers, and shifted muscle fiber types after combined nerve and muscle injury. Importantly, the 4-AP treatment significantly reduced PNI-induced bone loss. In contrast, in the case of isolated muscle injury, 4-AP had no effect on functional recovery and bone density, but it improved muscle-specific histomorphometry to a limited extent. CONCLUSIONS: These findings demonstrate the potential beneficial effects of 4-AP on the recovery of muscle morphology and bone density after combined muscle and nerve injury. CLINICAL RELEVANCE: Nerve injuries frequently involve muscle and result in rapid muscle and bone atrophy. In this scenario, 4-AP, in addition to accelerating nerve functional recovery, might work as an adjunctive agent to improve the recovery of injured muscle and attenuate PNI-induced bone loss.

Erythropoietin-PLGA-PEG as a local treatment to promote functional recovery and neurovascular regeneration after peripheral nerve injury.

BACKGROUND: Traumatic peripheral nerve injury (TPNI) is a major medical problem with no universally accepted pharmacologic treatment. We hypothesized that encapsulation of pro-angiogenic erythropoietin (EPO) in amphiphilic PLGA-PEG block copolymers could serve as a local controlled-release drug delivery system to enhance neurovascular regeneration after nerve injury. METHODS: In this study, we synthesized an EPO-PLGA-PEG block copolymer formulation. We characterized its physiochemical and release properties and examined its effects on functional recovery, neural regeneration, and blood vessel formation after sciatic nerve crush injury in mice. RESULTS: EPO-PLGA-PEG underwent solution-to-gel transition within the physiologically relevant temperature window and released stable EPO for up to 18 days. EPO-PLGA-PEG significantly enhanced sciatic function index (SFI), grip strength, and withdrawal reflex post-sciatic nerve crush injury. Furthermore, EPO-PLGA-PEG significantly increased blood vessel density, number of junctions, and myelinated nerve fibers after injury. CONCLUSION: This study provides promising preclinical evidence for using EPO-PLGA-PEG as a local controlled-release treatment to enhance functional outcomes and neurovascular regeneration in TPNI.

Animal model detects early pathologic changes of Charcot neuropathic arthropathy.

Charcot neuropathic arthropathy is a degenerative, debilitating disease that affects the foot and ankle in patients with diabetes and peripheral neuropathy, often resulting in destruction, amputation. Proposed etiologies include neurotraumatic, inflammatory, and neurovascular. There has been no previous animal model for Charcot. This study proposes a novel rodent model of induced neuropathic arthropathy to understand the earliest progressive pathologic changes of human Charcot. High-fat-diet-induced obese (DIO) Wild-type C57BL/6J mice (n = 8, diabetic) and age-matched low-fat-diet controls (n = 6) were run on an inclined high-intensity treadmill protocol four times per week for 7 weeks to induce mechanical neurotrauma to the hind-paw, creating Charcot neuropathic arthropathy. Sensory function and radiologic correlation were assessed; animals were sacrificed to evaluate hindpaw soft tissue and joint pathology. With this model, Charcot-DIO mice reveals early pathologic features of Charcot neuropathic arthropathy, a distinctive subchondral microfracture callus, perichondral/subchondral osseous hypertrophy/osteosclerosis, that precedes fragmentation/destruction observed in human surgical pathology specimens. There is intraneural vacuolar-myxoid change and arteriolosclerosis. The DIO mice demonstrated significant hot plate sensory neuropathy compared (P < 0.01), radiographic collapse of the longitudinal arch in DIO mice (P < 0.001), and diminished bone density in DIO, compared with normal controls. Despite exercise, high-fat-DIO mice increased body weight and percentage of body fat (P < 0.001). This murine model of diet-induced obesity and peripheral neuropathy, combined with repetitive mechanical trauma, simulates the earliest changes observed in human Charcot neuropathic arthropathy, of vasculopathic-neuropathic etiology. An understanding of early pathophysiology may assist early diagnosis and intervention and reduce patient morbidity and mortality in Charcot neuropathic arthropathy.

Obligatory role of Schwann cell-specific erythropoietin receptors in erythropoietin-induced functional recovery and neurogenic muscle atrophy after nerve injury.

BACKGROUND: Erythropoietin (EPO) promotes myelination and functional recovery in rodent peripheral nerve injury (PNI). While EPO receptors (EpoR) are present in Schwann cells, the role of EpoR in PNI recovery is unknown because of the lack of EpoR antagonists or Schwann cell-specific EpoR knockout animals. METHODS: Using the Cre-loxP system, we developed a myelin protein zero (Mpz) promoter-driven knockout mouse model of Schwann cell EpoR (MpzCre-EpoRflox/flox , Mpz-EpoR-KO). Mpz-EpoR-KO and control mice were assigned to sciatic nerve crush injury followed by EPO treatment. RESULTS: EPO treatment significantly accelerated functional recovery in control mice in contrast to significantly reduced functional recovery in Mpz-EpoR-KO mice. Significant muscle atrophy was found in the injured hindlimb of EPO-treated Mpz-EpoR-KO mice but not in EPO-treated control mice. CONCLUSIONS: These preliminary findings provide direct evidence for an obligatory role of Schwann-cell specific EpoR for EPO-induced functional recovery and muscle atrophy following PNI.

Process Mapping Total Knee Arthroplasty: A Comparison of Instrument Designs.

BACKGROUND: Total knee arthroplasty (TKA) is commonly performed with proprietary, manual instrumentation provided by the surgical implant manufacturer. Registry studies and meta-analysis, with few outliers, have consistently shown similar functional outcomes and implant survival after TKA regardless of implant manufacturer, implant design, or surgical technique. We hypothesized that process mapping could identify areas for improvement in TKA instrumentation. METHODS: Seventeen TKA implant systems from 10 companies representing over 90% of all TKAs performed in the United States were evaluated. Instrumentation required for femoral, tibial, and patellar preparation was compared. The number of steps including surgical technician assembly steps, instrument handoffs, and surgeon steps were tabulated based off application of a standardized surgical flow, adjusted for manufacturer-recommended steps during completion of a TKA operation. RESULTS: Cruciate-retaining (CR) knee instrumentation in studied systems required 158-225 discrete steps and posterior-stabilized (PS) knees required 181-230 steps. With the fewest steps for femoral, tibial, and patellar instrumentation, CR and PS knee systems could be improved to 145 and 163 steps, respectively. The Arthrex iBalance and the Biomet Vanguard Microplasty required fewest steps among CR systems; the OrthoDevelopment Balanced and the Corin Unity required fewest steps among PS systems. CONCLUSIONS: Process mapping identified potential areas for improved instrumentation in all studied systems, suggesting the possibility to reduce operative steps broadly across the TKA industry. Patient outcomes were not evaluated by system. Future implant system design changes may do well to reduce unnecessary steps and instrumentation.

Peripheral nerve injury and myelination: Potential therapeutic strategies.

Traumatic peripheral nerve injury represents a major clinical and public health problem that often leads to significant functional impairment and permanent disability. Despite modern diagnostic procedures and advanced microsurgical techniques, functional recovery after peripheral nerve repair is often unsatisfactory. Therefore, there is an unmet need for new therapeutic or adjunctive strategies to promote the functional recovery in nerve injury patients. In contrast to the central nervous system, Schwann cells in the peripheral nervous system play a pivotal role in several aspects of nerve repair such as degeneration, remyelination, and axonal growth. Several non-surgical approaches, including pharmacological, electrical, cell-based, and laser therapies, have been employed to promote myelination and enhance functional recovery after peripheral nerve injury. This review will succinctly discuss the potential therapeutic strategies in the context of myelination following peripheral neurotrauma.

4-Aminopyridine attenuates muscle atrophy after sciatic nerve crush injury in mice.

INTRODUCTION: We recently demonstrated the beneficial effects of 4-aminopyridine (4-AP), a potassium channel blocker, in enhancing remyelination and recovery of nerve conduction velocity and motor function after sciatic nerve crush injury in mice. Although muscle atrophy occurs very rapidly after nerve injury, the effect of 4-AP on muscle atrophy and intrinsic muscle contractile function is largely unknown. METHODS: Mice were assigned to sciatic nerve crush injury and no-injury groups and were followed for 3, 7, and 14 days with/without 4-AP or saline treatment. Morphological, functional, and transcriptional properties of skeletal muscle were assessed. RESULTS: In addition to improving in vivo function, 4-AP significantly reduced muscle atrophy with increased muscle fiber diameter and contractile force. Reduced muscle atrophy was associated with attenuated expression of atrophy-related genes and increased expression of proliferating stem cells. DISCUSSION: These findings provide new insights into the potential therapeutic benefits of 4-AP against nerve injury-induced muscle atrophy and dysfunction. Muscle Nerve 60: 192-201, 2019.

Erythropoietin accelerates functional recovery after moderate sciatic nerve crush injury.

INTRODUCTION: Erythropoietin (EPO) has been identified as a neuroregenerative agent. We hypothesize that it may accelerate recovery after crush injury and may vary with crush severity. METHODS: Mice were randomized to mild, moderate, or severe crush of the sciatic nerve and were treated with EPO or vehicle control after injury. The sciatic function index (SFI) was monitored over the first week. Microstructural changes were analyzed by immunofluorescence for neurofilament (NF) and myelin (P0 ), and electron microscopy was used to assess ultrastructural changes. RESULTS: In moderate crush injuries, EPO significantly improved SFI at 7 days post-injury, an effect not observed with other severity levels. Increases in the ratio of P0 to NF were observed after EPO treatment in moderate crush injuries. Electron microscopy demonstrated endothelial cell hypertrophy in the EPO group. CONCLUSIONS: EPO accelerates recovery in moderately crushed nerves, which may be through effects on myelination and vascularization. Injury severity may influence the efficacy of EPO. Muscle Nerve 56: 143-151, 2017.

Is medial elbow pain correlated with cubital tunnel syndrome? An electrodiagnostic study.

INTRODUCTION: Medial elbow pain is often considered to be a symptom associated with ulnar neuropathy at the elbow (UNE). We examined the relationship between medial elbow pain and a positive electrodiagnostic (EDx) test result for UNE. METHODS: We performed a retrospective review of 884 patients referred for EDx evaluation of UNE. Regression models were used to determine the odds ratios between clinical findings and a positive EDx result for UNE. RESULTS: Patients reported medial elbow pain in 44.3% of cases. Clinical factors that correlated with a positive EDx study result for UNE included male gender, small and ring finger numbness, ulnar intrinsic weakness, and age. Medial elbow pain was negatively correlated with a positive EDx result. CONCLUSIONS: This study demonstrates a negative correlation between medial elbow pain and a positive EDx result for UNE. Medial elbow pain should not be considered a clear diagnostic symptom of UNE.

A Peculiar Primary Paraganglioma of the Distal Thumb.

A paraganglioma is a highly vascularized neuroendocrine tumor most commonly found within the adrenal gland as a pheochromocytoma. Extra-adrenal paragangliomas are frequently located in the head, neck, thorax, and abdomen. We report the first documented case of a primary paraganglioma found within the appendicular skeleton. Only 2 additional cases of paragangliomas in the extremities have been documented, one in the soft tissue of the forearm and other within the median nerve. Our patient underwent amputation of the distal phalanx, with no sign of recurrence at greater than 1 year of follow-up. Because of the geographic and clinical similarity to a benign enchondroma, radiographic imaging alone may not be sufficient to rule out malignancies inside bones. Thus paraganglioma should remain in the differential and immunohistochemistry is both vital and necessary to confirm the diagnosis. Vigilant and appropriate follow-up is necessary to detect metastases early in these patients.

Radiographic Parameters to Predict Union After Volar Percutaneous Fixation of Herbert Type B1 and B2 Scaphoid Fractures.

PURPOSE: To study the angle of screw placement in relation to the scaphoid fracture plane and its effect on union after percutaneous fixation of scaphoid waist fractures. METHODS: Twenty-four consecutive scaphoid waist fractures were retrospectively evaluated for the orientation of screws in relation to the fracture plane using a method in which the sum-of-smaller angles (SSA) in 3 different radiographs were used to correlate with time to fracture union. RESULTS: All but one patient achieved union after percutaneous fixation of the scaphoid. Another patient required revision surgery within the study period for inadequate fixation. A shortened time to union was significantly correlated to larger SSA. CONCLUSIONS: SSA may be a reasonable predictor of union after percutaneous fixation of scaphoid waist fracture. It can be reliably calculated using plain radiographs. An SSA of 190° or more correlated with union by 8 weeks postoperatively.

Hand Sensibility, Strength, and Laxity of High-Level Musicians Compared to Nonmusicians.

PURPOSE: To determine whether musicians have more sensitive, stronger, and flexible hands than nonmusicians. METHODS: A total of 100 musicians and 100 control subjects were assessed for 2-point discrimination, Semmes-Weinstein monofilament light touch, grip and pinch strength, and laxity. Musicians were included if enrolled as instrumental performance majors at a 4-year accredited conservatory of music. Nonmusician controls were university students who never or rarely engaged in playing an instrument. All subjects were between the ages of 18 and 28. The exclusion criterion was history of any hand condition, trauma, surgery, or diabetes. Statistical analyses were carried out using the t test, analysis of variance, and correlation coefficients as appropriate. RESULTS: High-level musicians in our cohort showed the same handedness (dominance) as the general population. The musicians were weaker than the nonmusicians. Male musicians were significantly weaker in pinch and grip bilaterally than nonmusicians, whereas female musicians were significantly weaker only in grip on the right/dominant side. Two-point discrimination was significantly less in musicians for the left/nondominant index, ring, and small fingers, and the right/dominant small and dominant index finger. Semmes-Weinstein testing was significantly better for the right/dominant digits, including the thumb, but not the left digits with the exception of the ring and nondominant middle and ring. There was no difference in laxity between the 2 groups. CONCLUSIONS: High-level musicians have, in general, more sensitive but weaker hands than nonmusicians, but the differences seem small and may not be clinically important.

Distal Radioulnar Joint Reaction Force Following Ulnar Shortening: Diaphyseal Osteotomy Versus Wafer Resection.

PURPOSE: To compare how ulnar diaphyseal shortening and wafer resection affect distal radioulnar joint (DRUJ) joint reaction force (JRF) using a nondestructive method of measurement. Our hypothesis was that ulnar shortening osteotomy would increase DRUJ JRF more than wafer resection. METHODS: Eight fresh-frozen human cadaveric upper limbs were obtained. Under fluoroscopic guidance, a threaded pin was inserted into the lateral radius orthogonal to the DRUJ and a second pin was placed in the medial ulna coaxial to the radial pin. Each limb was mounted onto a mechanical tensile testing machine and a distracting force was applied across the DRUJ while force and displacement were simultaneously measured. Data sets were entered into a computer and a polynomial was generated and solved to determine the JRF. This process was repeated after ulnar diaphyseal osteotomy, ulnar re-lengthening, and ulnar wafer resection. The JRF was compared among the 4 conditions. RESULTS: Average baseline DRUJ JRF for the 8 arms increased significantly after diaphyseal ulnar shortening osteotomy (7.2 vs 10.3 N). Average JRF after re-lengthening the ulna and wafer resection was 6.9 and 6.7 N, respectively. There were no differences in JRF among baseline, re-lengthened, and wafer resection conditions. CONCLUSIONS: Distal radioulnar joint JRF increased significantly after ulnar diaphyseal shortening osteotomy and did not increase after ulnar wafer resection. CLINICAL RELEVANCE: Diaphyseal ulnar shortening osteotomy increases DRUJ JRF, which may lead to DRUJ arthrosis.

The Effect of the Epitendinous Suture on Gliding in a Cadaveric Model of Zone II Flexor Tendon Repair.

PURPOSE: We hypothesized that increasing core sutures (4-6) may be preferable in terms of gliding coefficient (GC) measurements when compared with adding an epitendinous suture to zone II flexor tendon repairs. We hypothesized that the inclusion of epitendinous suture in 2 standard repairs would contribute negatively to the GC of the repaired tendon. METHODS: Nineteen fresh-frozen cadaveric fingers were used for testing. We compared a control group (dissected digits without repair) and 4-strand or 6-strand core tendon repairs with and without epitendinous suture. Arc of motion was driven by direct loading, and digital images were acquired and analyzed. Outcomes were defined as the difference in GC between the native uninjured and the repaired state at each load. A linear mixed-model analysis was performed with comparisons between repairs to evaluate the statistically relevant differences between groups. RESULTS: The test of fixed effects in the linear model revealed that repair type and the use of epitendinous suture significantly affected the change in GC. The addition of an epitendinous suture produced a significant decrement in gliding regardless of repair type. CONCLUSIONS: There was significant improvement in GC with the omission of the epitendinous suture in both repair types (4- or 6-strand). CLINICAL RELEVANCE: The epitendinous suture used in this model resulted in poorer gliding of the repair, which may correspond with an expected increase in catching or triggering.

A nondestructive, reproducible method of measuring joint reaction force at the distal radioulnar joint.

PURPOSE: To develop a nondestructive method of measuring distal radioulnar joint (DRUJ) joint reaction force (JRF) that preserves all periarticular soft tissues and more accurately reflects in vivo conditions. METHODS: Eight fresh-frozen human cadaveric limbs were obtained. A threaded Steinmann pin was placed in the middle of the lateral side of the distal radius transverse to the DRUJ. A second pin was placed into the middle of the medial side of the distal ulna colinear to the distal radial pin. Specimens were mounted onto a tensile testing machine using a custom fixture. A uniaxial distracting force was applied across the DRUJ while force and displacement were simultaneously measured. Force-displacement curves were generated and a best-fit polynomial was solved to determine JRF. RESULTS: All force-displacement curves demonstrated an initial high slope where relatively large forces were required to distract the joint. This ended with an inflection point followed by a linear area with a low slope, where small increases in force generated larger amounts of distraction. Each sample was measured 3 times and there was high reproducibility between repeated measurements. The average baseline DRUJ JRF was 7.5 N (n = 8). CONCLUSIONS: This study describes a reproducible method of measuring DRUJ reaction forces that preserves all periarticular stabilizing structures. This technique of JRF measurement may also be suited for applications in the small joints of the wrist and hand. CLINICAL RELEVANCE: Changes in JRF can alter native joint mechanics and lead to pathology. Reliable methods of measuring these forces are important for determining how pathology and surgical interventions affect joint biomechanics.

Flexor digitorum superficialis repair outside the A2 pulley after zone II laceration: gliding and bowstringing.

PURPOSE: To evaluate the changes in maximum flexion angle, gliding coefficient, and bowstringing after a combined repair of both flexor tendons with the flexor digitorum superficialis (FDS) rerouted outside the A2 pulley in cadaveric hands. METHODS: We performed 4 different repairs on cadaveric hands, with each repair tested on 9 unique digits. In total, 12 cadaveric hands and 36 digits were used. The thumb and little finger were removed from each hand and excluded from testing. Group 1 was sham surgery. Group 2 combined flexor digitorum profundus (FDP) and FDS laceration and repair with both slips of the FDS repaired inside the A2 pulley. Group 3 was FDP repair with one slip of the FDS repaired inside A2 and the other slip left unrepaired. Group 4 was FDP repair with both slips of the FDS rerouted and repaired outside the A2 pulley. Maximum flexion angle, gliding coefficient, and bowstringing were measured in simulated active digital motion for each group. RESULTS: Rerouting and repairing the FDS outside the A2 pulley (group 4) significantly lowered gliding coefficient compared with repairs with both slips inside A2, with values similar to sham surgery. We observed no significant differences in maximum flexion angle among the 4 groups. Increased bowstringing was observed with both slips of the FDS repaired and rerouted outside the A2 pulley. CONCLUSIONS: In this cadaveric model, repair of both slips of the FDS outside the A2 pulley improved the gliding coefficient relative to repair within the A2 pulley, which suggests decreased resistance to finger flexion. Repair of the FDS outside the A2 pulley led to a slight increase in bowstringing of the FDS tendon. CLINICAL RELEVANCE: We describe a technique for managing combined laceration of the FDP and FDS tendons that improves gliding function and merits consideration.

Management of neglected Bennett fracture in manual laborers by tension fixation.

PURPOSE: To report the results of open reduction and internal fixation (ORIF) of Bennett fractures in young, active patients using a K-wire and wire loop construct to achieve anatomical reduction and to allow return to manual labor. METHODS: In this prospective series, we treated 10 male manual laborers (mean age, 30 y; range, 20-44 y) with Bennett fractures diagnosed after a minimum of 12 weeks (mean, 16 wk; range, 12-18 wk). ORIF using 2 K-wires with a wire loop and a neutralizing transarticular K-wire was performed with direct articular visualization. Patients were evaluated for range of motion, grip strength, and pinch strength, and a visual analog scale score rated pain before surgery and 12 months later. RESULTS: The mean follow-up was 16 months (range, 12-36 mo). The average visual analog scale improved from 6 to 2, mean palmar abduction improved from 15° to 40°, mean radial abduction increased from 22° to 39°, average pinch strength improved from 9.9 kg to 15.5 kg, and average grip strength increased from 34 kg to 49 kg. Complications included transient irritation of the radial sensory nerve or lateral cutaneous nerve of the forearm in 3 patients, pin track granuloma formation in 2 patients, and marginal osteophyte formation in 2 patients. Union was achieved in all 10 patients, and 9 patients returned to their previous manual labor occupation. CONCLUSIONS: Our results suggest that neglected Bennett fractures can be effectively managed by ORIF using K-wires and a wire loop without compromising strength or motion. This technique reliably restored the anatomy and provided adequate thumb motion and strength to allow a return to manual labor. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Shear wave elastography of transverse carpal ligament increased with simulated carpal tunnel pressure.

BACKGROUND: Elevation of carpal tunnel pressure is known to be associated with carpal tunnel syndrome. This study aimed to correlate the shear wave elastography in the transverse carpal ligament (TCL) with carpal tunnel pressures using a cadaveric model. METHODS: Eight human cadaveric hands were dissected to evacuate the tunnels. A medical balloon was inserted into each tunnel and connected to a pressure regulator to simulate tunnel pressure in the range of 0-210 mmHg with an increment of 30 mmHg. Shear wave velocity and modulus was measure in the middle of TCL. RESULTS: SWV and SWE were significantly dependent on the pressure levels (p < 0.001), and positively correlated to the tunnel pressure (SWV: R = 0.997, p < 0.001; SWE: R = 0.996, p < 0.001). Regression analyses showed linear relationship SWV and pressure (SWV = 4.359 + 0.0263 * Pressure, R2 = 0.994) and between SWE and pressure (SWE = 48.927 + 1.248 * Pressure, R2 = 0.996). CONCLUSION: The study indicated that SWV and SWE in the TCL increased linearly as the tunnel pressure increased within the current pressure range. The findings suggested that SWV/SWE in the TCL has the potential for prediction of tunnel pressure and diagnosis of carpal tunnel syndrome.