A preliminary study of radioulnar wrist compression in improving patient-reported outcomes of carpal tunnel syndrome.

Previous studies have shown radioulnar wrist compression augments carpal arch space. This study investigated the effects of radioulnar wrist compression on patient-reported outcomes associated with carpal tunnel syndrome. Subjects underwent thrice-daily (15 min each time 45 min daily) wrist compression over 4 weeks with an additional four weeks of follow-up without treatment. Primary outcomes included Boston Carpal Tunnel Questionnaire symptom and functional severity scales (SSS and FSS) and symptoms of numbness/tingling based on Visual Analog Scales. Our results showed that radioulnar wrist compression improved SSS by 0.55 points after 2 weeks (p < 0.001) and 0.51 points at 4 weeks (p < 0.006) compared to the baseline scale. At the four-week follow-up, SSS remined improved at 0.47 points (p < 0.05). Symptoms of numbness/tingling improved at two and 4 weeks, as well as the follow-up (p < 0.05). Hand motor impairment such as weakness had a lower frequency across carpal tunnel syndrome sufferers and does not significantly improve (p > 0.05). Radioulnar wrist compression might be an effective alternative treatment in improving sensory related symptoms in patients with mild to moderate carpal tunnel syndrome.

Triceps tongue versus olecranon osteotomy for intra-articular distal humeral fractures: a matched-cohort study.

BACKGROUND: There are various approaches to the distal humerus when managing a distal humeral fracture, and controversy exists regarding which approach is optimal. The purpose of this study was to report the outcomes of the triceps tongue (TT) approach when used for osteosynthesis of AO type 13-A, B, and C distal humeral fractures. Secondarily, we aimed to compare the outcomes of the TT approach vs. olecranon osteotomy (OO) when used for osteosynthesis of AO type 13-C distal humeral fractures. METHODS: We performed a retrospective review of patients with distal humeral fractures treated with open reduction-internal fixation by either a TT or OO approach between 2007 and 2019 at 2 separate institutions. TT patients with AO type 13-C fractures were matched to OO patients at a 1:1 ratio based on age, sex, and fracture characteristics. Surgical time, intraoperative blood loss, elbow motion, fracture union, complications, and Disabilities of the Arm, Shoulder and Hand scores were compared. RESULTS: A total of 28 patients treated with the TT approach were assessed, and the matched TT and OO cohorts each comprised 15 patients. The TT group showed less blood loss (119.3 mL vs. 268.5 mL, P = .03), had greater maximal flexion (126° vs. 116°, P = .03), and achieved a larger flexion-extension arc (108° vs. 93°, P = .05) than the OO group. In the OO cohort, 27% of patients had complications directly related to the OO, and OO patients had a higher rate of postoperative ulnar nerve neuritis (33% vs. 0%, P = .04). There was no difference in Disabilities of the Arm, Shoulder and Hand score (P = .08), procedure time (P = .2), total number of patients with ≥1 complication (P = .5), difficulty with union (P = .7), or number of patients requiring revision surgery (P = .7). CONCLUSIONS: The TT approach is a safe and effective approach for the treatment of distal humeral fractures. When compared with the OO approach for AO type 13-C fractures, the TT approach did not differ regarding functional outcomes but showed increased range of motion, decreased intraoperative blood loss, and a lower rate of postoperative ulnar nerve neuritis. The TT approach should be considered as a safe and reliable first-line approach for intra-articular distal humeral fractures because it allows adequate visualization of the articular surface, eliminates complications related to osteotomy including delayed union or nonunion and hardware failure or irritation, and allows for easy conversion to total elbow arthroplasty.

The Van Gorder approach for total elbow arthroplasty.

BACKGROUND: Surgical management of the triceps during exposure for total elbow arthroplasty (TEA) is critical to a successful outcome. Previously described techniques include elevating the triceps insertion from one side or leaving the triceps insertion attached and dislocating the joint. Another approach to the elbow, first described in 1933 by Willis Campbell, MD, and subsequently modified by George Van Gorder, MD, involves turning down the triceps tendon without disrupting the triceps insertion. This approach offers complete visualization of the joint and provides excellent exposure for TEA. Only the original report of the technique and a small series of patients using this technique for TEA exist in the literature. The goal of this study was to evaluate outcomes of the Van Gorder approach in a large series of patients undergoing TEA. METHODS: All patients who underwent TEA from 2008 to 2016 were retrospectively reviewed. Only patients who underwent primary TEA performed through the Van Gorder approach with at least 6 months' follow-up were included for analysis. Patients with prior elbow surgery were excluded. Demographic data, indication for surgery, postoperative range of motion, triceps function, and need for additional surgery were recorded. Prospectively collected visual analog scale (VAS) and Global Health Quality of Life scores were also analyzed. RESULTS: A total of 53 patients met inclusion criteria. The mean age was 62 years, 81% were female, and the average follow-up was 30.2 months. The most common surgical indications included inflammatory arthritis (47%), osteoarthritis (24%), and fracture (19%). Postoperatively, average elbow arc of motion was an 8°-137°. There was 1 patient (1.89%) who developed failure of their triceps extension mechanism. A total of 10 patients (19%) underwent additional elbow surgery most commonly for superficial wound complications. Preoperative VAS scores decreased significantly, starting at 3 months postoperatively (6.76 to 3.37, P < .001), and remained constant at the 12- and 24-month postoperative visits. CONCLUSIONS: This is the largest study evaluating the Van Gorder surgical approach to the elbow for primary TEA with an average follow-up of 32 months. Overall rates of triceps failure and reoperation are consistent with other approaches for TEA.

Evidence-Based Approach to Timing of Nerve Surgery: A Review.

ABSTRACT: Events causing acute stress to the health care system, such as the COVID-19 pandemic, place clinical decisions under increased scrutiny. The priority and timing of surgical procedures are critically evaluated under these conditions, yet the optimal timing of procedures is a key consideration in any clinical setting. There is currently no single article consolidating a large body of current evidence on timing of nerve surgery. MEDLINE and EMBASE databases were systematically reviewed for clinical data on nerve repair and reconstruction to define the current understanding of timing and other factors affecting outcomes. Special attention was given to sensory, mixed/motor, nerve compression syndromes, and nerve pain. The data presented in this review may assist surgeons in making sound, evidence-based clinical decisions regarding timing of nerve surgery.

Location-dependent change of median nerve mobility in the carpal tunnel of patients with carpal tunnel syndrome.

INTRODUCTION: The purpose of this study was to investigate in vivo median nerve longitudinal mobility in different segments of the carpal tunnel associated with active finger motion in carpal tunnel syndrome (CTS) patients in a comparison with healthy controls. METHODS: Eleven healthy volunteers and 11 CTS patients participated in this study. Dynamic ultrasound images captured location-dependent longitudinal median nerve mobility within the carpal tunnel during finger flexion at the metacarpophalangeal joints using a speckle cross-correlation algorithm. RESULTS: Median nerve longitudinal mobility in the carpal tunnel was significantly smaller in CTS patients (0.0037 ± 0.0011 mm/degree) compared with controls (0.0082 ± 0.0026 mm/degree) (P < .05), especially in the proximal (0.0064 vs 0.0132 mm/degree on average) and middle (0.0033 vs 0.0074 mm/degree on average) carpal tunnel sections. DISCUSSION: Median nerve mobility can potentially serve as a biomechanical marker when diagnosing CTS, or when assessing the effectiveness of surgical and conservative treatments.

The Management of Persistent and Recurrent Cubital Tunnel Syndrome.

Cubital tunnel syndrome (CuTS) is the second most common compressive neuropathy in the upper extremity. There are considerable diagnostic and therapeutic challenges associated with treating patients after a failed primary procedure for CuTS. Distinguishing cases of recurrence versus persistence and identifying concomitant pathology can guide treatment. Conditions that mimic CuTS must be carefully ruled out and coexisting dysfunction of the medial antebrachial cutaneous nerve needs to be addressed. Results of revision procedures are not as reliable as primary procedures for CuTS; however, improvements in pain and paresthesias are noted in approximately 75% of patients. Nerve wraps represent a promising adjuvant treatment option, but long-term outcome data are lacking. External neurolysis and anterior transposition after failed CuTS procedures are supported by case series; multicenter, prospective randomized trials are needed to guide treatment further and improve outcomes.

Effects of Carpal Tunnel Syndrome on Force Coordination and Muscle Coherence during Precision Pinch.

Carpal tunnel syndrome (CTS), caused by entrapment of the median nerve in the carpal tunnel, impairs hand function including dexterous manipulation. The purpose of this study was to investigate the effects of CTS on force coordination and muscle coherence during low-intensity sustained precision pinch while the wrist assumed different postures. Twenty subjects (10 CTS patients and 10 asymptomatic controls) participated in this study. An instrumented pinch device was used to measure the thumb and index finger forces while simultaneously collecting surface electromyographic activities of the abductor pollicis brevis (APB) and first dorsal interosseous (FDI) muscles. Subjects performed a sustained precision pinch at 10% maximum pinch force for 15 sec with the wrist stabilized at 30° extension, neutral, or 30° flexion using customized splints. The force discrepancy and the force coordination angle between the thumb and index finger forces were calculated, as well as the ß-band (15-30 Hz) coherence between APB and FDI. The index finger applied greater force than the thumb (p < 0.05); this force discrepancy was increased with wrist flexion (p < 0.05), but was not affected by CTS (p > 0.05). The directional force coordination was not significantly affected by wrist posture or CTS (p > 0.05). In general, digit force coordination during precision pinch seems to be sensitive to wrist flexion, but is not affected by CTS. The ß-band muscular coherence was increased by wrist flexion for CTS patients (p < 0.05), which could be a compensatory mechanism for the flexion-induced exacerbation of CTS symptoms. This study demonstrates that wrist flexion negatively influences muscle and force coordination in CTS patients supporting the avoidance of flexion posture for symptom exacerbation and functional performance.

Technical Assessment of Connector-Assisted Nerve Repair.

PURPOSE: Clinical outcomes of nerve repair have not substantially improved over the last several decades. Although clearly a multifactorial problem, basic principles including proper fascicular alignment are not always realized. The use of short conduits as connectors may enhance nerve alignment by entubulating and directing the approximation of nerve ends. METHODS: Ten hand surgeons (5 experienced and 5 inexperienced) performed a series of in vitro human cadaver nerve repairs. Three small-diameter (2 mm), 3 medium-diameter (3-4 mm), and 3 large-diameter (5-6 mm) nerves were repaired (under 10× magnification) utilizing each of 3 techniques: suture-only, connector-only (sutures placed through the ends of the connector), and connector-assisted (alignment sutures at the nerve interface plus connector). Three judges (blinded to who performed the repairs) assessed each repair for fascicular alignment based on predetermined qualitative scales. RESULTS: Across all surgeons, 23 of 30 connector-assisted repairs were judged good or excellent versus 18 of 30 of the suture-only and 13 of 30 of the connector-only repairs. Experienced surgeons in general did better repairs and in particular were more likely to obtain superior alignment for conduit-only repairs (73.3% vs 13.3% good or excellent) and suture-only repairs (73.3% vs 46.7% good or excellent) and were not statistically different for connector-assisted repairs (86.7% vs 66.7% good or excellent) compared with inexperienced surgeons. CONCLUSIONS: In a cadaver nerve model, there was no significant difference in the technical alignment of conduit-assisted repairs between experienced and inexperienced surgeons whereas inexperienced surgeons were more likely to achieve inadequate alignment with suture-only or conduit-only repairs. CLINICAL RELEVANCE: Connector-assisted repairs combining suture-approximation and entubulation may improve the technical alignment of nerve repairs performed, especially by less-experienced surgeons.

Thickness and Stiffness Adaptations of the Transverse Carpal Ligament Associated with Carpal Tunnel Syndrome.

The purpose of this study was to investigate the morphological and mechanical properties of the transverse carpal ligament (TCL) in patients with carpal tunnel syndrome (CTS). Thickness and stiffness of the TCL in eight female CTS patients and eight female control subjects were examined using ultrasound imaging modalities. CTS patients had a 30.9% thicker TCL than control subjects. There was no overall difference in TCL stiffness between the two groups, but the radial TCL region was significantly stiffer than the ulnar region within the CTS group and such a regional difference was not found for the controls. The increased thickness and localized stiffness of the TCL for CTS patients may contribute to CTS symptoms due to reduction in carpal tunnel space and compliance. Advancements in ultrasound technology provide a means of understanding CTS mechanisms and quantifying the morphological and mechanical properties of the TCL in vivo.

Maintenance of in vivo induced cytochrome P-450s in hepatocyte monolayers at non freezing temperatures.

Cytochrome P450s (CYPs) induced in rats by 3-methylcholanthrene (3-MC), phenobarbital (PB) and dexamethasone (Dex) were investigated. The inducers had no effect on hepatocyte yield, viability, attachment or spreading on collagen. 3-MC induced ethoxyresorufin deethylase (EROD). Under normothermic conditions the activity fell in culture. However, it was maintained when cells were preserved at 10°C under a gelatin gel. Upon reactivation the activity mirrored that of freshly isolated cells at 37°C. Induced levels were stable for at least 6h , the time to form a confluent monolayer. The investigation was extended to other CYPs by looking at patterns of testosterone metabolism. Phenobarbital had the greatest influence in terms of the quantity and number of metabolites. Culture at 37°C decreased the peaks dramatically within 24 h. All 7 peaks were maintained in the preservation system.

Carpal tunnel syndrome impairs thumb opposition and circumduction motion.

BACKGROUND: Carpal tunnel syndrome is associated with sensory and motor impairments resulting from the compressed and malfunctioning median nerve. The thumb is critical to hand function, yet the pathokinematics of the thumb associated with carpal tunnel syndrome are not well understood. QUESTIONS/PURPOSES: The purpose of this study was to evaluate thumb motion abnormalities associated with carpal tunnel syndrome. We hypothesized that the ranges of translational and angular motion of the thumb would be reduced as a result of carpal tunnel syndrome. METHODS: Eleven patients with carpal tunnel syndrome and 11 healthy control subjects voluntarily participated in this study. Translational and angular kinematics of the thumb were obtained using marker-based video motion analysis during thumb opposition and circumduction movements. RESULTS: Motion deficits were observed for patients with carpal tunnel syndrome even though maximum pinch strength was similar. The path length, normalized by palm width of the thumb tip for the patients with carpal tunnel syndrome was less than for control participants (opposition: 2.2 palm width [95% CI, 1.8-2.6 palm width] versus 3.1 palm width [95% CI, 2.8-3.4 palm width], p < 0.001; circumduction: 2.2 palm width [95% CI, 1.9-2.5 palm width] versus 2.9 palm width [95% CI, 2.7-3.2 palm width], p < 0.001). Specifically, patients with carpal tunnel syndrome had a deficit of 0.3 palm width (95% CI, 0.04-0.52 palm width; p = 0.022) in the maximum position of their thumb tip ulnarly across the palm during opposition relative to control participants. The angular ROM also was reduced for the patients with carpal tunnel syndrome compared with the control participants in extension/flexion for the metacarpophalangeal (opposition: 34° versus 58°, p = .004; circumduction: 33° versus 58°, p < 0.001) and interphalangeal (opposition: 37° versus 62°, p = .028; circumduction: 41° versus 63°, p = .025) joints. CONCLUSIONS: Carpal tunnel syndrome disrupts kinematics of the thumb during opposition and circumduction despite normal pinch strength. CLINICAL RELEVANCE: Improving understanding of thumb pathokinematics associated with carpal tunnel syndrome may help clarify hand function impairment associated with the syndrome given the critical role of the thumb in dexterous manipulation.

Radiographic assessment of prosthetic humeral head size after anatomic shoulder arthroplasty.

BACKGROUND: Restoring the premorbid proximal humeral anatomy during shoulder arthroplasty is critical yet can be difficult because of the deformity of the arthritic head. The purpose of this study was to measure the variation between surgeons and between types of prosthetics in reproducing the anatomic center of rotation (COR) of the humeral head after anatomic shoulder arthroplasty. METHODS: The anteroposterior radiographs of 125 stemmed and 43 resurfacing shoulder arthroplasties, performed by 5 experienced surgeons, were analyzed. All patients had primary replacement for treatment of end-stage glenohumeral arthritis. A best-fit circle to preserved nonarticular humeral landmarks was used to define the difference between the anatomic COR and the prosthetic COR. A difference in COR of >3.0 mm was considered clinically significant and analyzed for the cause of this deviation. RESULTS: The average deviation of the postoperative COR from the anatomic COR was 2.5 ± 1.6 mm for stemmed cases and 3.8 ± 2.1 mm for resurfacings. Thirty-nine stemmed cases (31.2%) and 28 resurfacings (65.1%) were beyond 3.0 mm of deviation and regarded as outliers. The majority of the stemmed outliers and all resurfacing outliers were overstuffed. An improper humeral head size selection and inadequate reaming were the main reasons for the deviation in stemmed and resurfacing outliers, respectively. CONCLUSION: A large percentage of shoulder replacements demonstrated significant deviations from an anatomic reconstruction. Resurfacing arthroplasty exhibited significantly greater deviations compared with stemmed arthroplasty (P < .001), indicating that surgeons have more difficulty in restoring the anatomy with resurfacings. Further studies are needed to assess the clinical impact of these deviations.

Prevention and treatment of elbow stiffness: a 5-year update.

Elbow stiffness is a challenging and common problem faced by upper extremity surgeons. Although functional improvements can be made with both nonsurgical and surgical management strategies, physicians must remain vigilant with efforts to prevent stiffness before it starts. Recent advancements in the biology and pathology of elbow contracture have led to improved understanding of this difficult problem, and they may lead to future breakthroughs in the prevention and treatment of elbow stiffness. This article serves as an update to our previous review of elbow stiffness, focusing on recent advancements in the past 5 years, as well as updating our current algorithm for treatment.

A Systematic Review and Meta-Analysis of Nerve Gap Repair: Comparative Effectiveness of Allografts, Autografts, and Conduits.

BACKGROUND: Ideal nerve repair involves tensionless direct repair, which may not be possible after resection. Bridging materials include nerve autograft, allograft, or conduit. This study aimed to perform a systematic literature review and meta-analysis to compare the meaningful recovery (MR) rates and postoperative complications following autograft, allograft, and conduit repairs in nerve gaps greater than 5 mm and less than 70 mm. A secondary aim was to perform a comparison of procedure costs. METHODS: The search was conducted in MEDLINE from January of 1980 to March of 2020, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were included whether they reported nerve injury type, repair type, gap length, and outcomes for MR rates. Thirty-five studies with 1559 nerve repairs were identified. RESULTS: Overall MR for sensory and motor function was not significantly different between autograft ( n = 670) and allograft ( n = 711) across both short and long gaps. However, MR rates for autograft (81.6%) and allograft (87.1%) repairs were significantly higher compared with conduits (62.2%) ( P < 0.05) in sensory short gap repairs. Complication rates were comparable for autograft and allograft but higher for conduit with regard to pain. Analysis of costs showed that total costs for allograft repair were less than autograft in the inpatient setting and were comparable in the outpatient setting. CONCLUSIONS: Literature showed comparable rates of MR between autograft and allograft, regardless of gap length or nerve type. Furthermore, the rates of MR were lower in conduit repairs. In addition, the economic analysis performed demonstrates that allograft does not represent an increased economic burden compared with autograft.

Validation of a Smartphone-Based Institutional Electronic Data Capture System for Thumb Carpometacarpal Joint Arthroplasty.

BACKGROUND: The Orthopaedic Minimal Data Set (OrthoMiDaS) Episode of care (OME) is a prospectively collected database enabling capture of patient and surgeon-reported data in a more efficient, comprehensive, and dependable manner than electronic medical record (EMR) review. We aimed to assess and validate the OME as a data capture tool for carpometacarpal (CMC) arthroplasty compared to traditional EMR-based review. Specifically, we aimed to: (1) compare the completeness of the OME versus EMR data; and (2) evaluate the extent of agreement between the OME and EMR data-based datasets for carpometacarpal (CMC) arthroplasty. METHODS: The first 100 thumb CMC arthroplasties after OME inception (Febuary, 2015) were included. Blinded EMR-based review of the same cases was performedfor 48 perioperative variables and compared to their OME-sourced counterparts. Outcomes included completion rates and agreement measures in OME versus EMR-based control datasets. RESULTS: The OME demonstrated superior completion rates compared to EMR-based retrospective review. There was high agreement between both datasets where 75.6% (34/45) had an agreement proportion of >0.90% and 82.2% (37/45) had an agreement proportion of >0.80. Over 40% of the variables had almost perfect to substantial agreement (κ > 0.60). Among the 6 variables demonstrating poor agreement, the surgeon-inputted OME values were more accurate than the EMR-based review control. CONCLUSIONS: This study validates the use of the OME for CMC arthroplasty by illustrating that it is reliably able to match or supersede traditional chart review for data collection; thereby offering a high-quality tool for future CMC arthroplasty studies.

Prevention of hypothermic haloing extends the preservation time of hepatocytes at non freezing temperatures.

Factors limiting the hypothermic preservation of hepatocytes on gelatin gels at 10 °C were investigated. Following 4 days of preservation, uniform morphological changes started to appear. The cells exhibited halos that increased in size. The particulate matter of the cell was confined to the central region. Cell viability was reduced from day 7 onwards. Neither fresh media changes nor the use of conditions to minimise free radical formation improved cell survival. However, haloing was decreased by short term temperature elevation to 37 °C (3 h), to reactivate the cells, and could be prevented completely by a stepwise increase in the sucrose concentration of the medium. The addition of sucrose in increments of 50 mM, at four day intervals, was found to inhibit morphological change. Prevention of haloing enabled the cells to be preserved for at least two weeks. The preserved cells attached to supports and spread as if freshly isolated. The procedure allows extended preservation of cells at non-freezing temperatures.

Biomechanical properties of fixed-angle volar distal radius plates under dynamic loading.

PURPOSE: To evaluate and compare the biomechanical properties of 8 different locked fixed-angle volar distal radius plates under conditions designed to reflect forces seen in early fracture healing and postoperative rehabilitation. METHODS: We evaluated the Acumed Acu-Loc (Acumed, Hillsboro, OR), Hand Innovations DVR (Hand Innovations, Miami, FL), SBi SCS volar distal radial plate (Small Bone Innovations, Morrisville, PA), Synthes volar distal radius plate and EA extra-articular volar distal radius plate (Synthes, Paoli, PA), Stryker Matrix-SmartLock (Stryker Leibinger, Kalamazoo, MI), Wright Medical Technology Locon VLS (Wright Medical Technology, Arlington, TN), and Zimmer periarticular distal radius locking plate (Zimmer, Warsaw, IN). After affixing each plate to a synthetic corticocancellous radius, we created a standardized dorsal wedge osteotomy. Each construct had cyclic loading of 100 N, 200 N, and 300 N for a total of 6000 cycles. Outcomes, including load deformation curves, displacement, and ultimate yield strengths, were collected for each construct. RESULTS: The Wright plate was significantly stiffer at the 100 N load than the Zimmer plate and was stiffer at the 300 N load than 4 other plates. The Zimmer and Hand Innovations plates had the highest yield strengths and significantly higher yield strengths than the Wright, SBi, Stryker, and Synthes EA plates. CONCLUSIONS: Given the biomechanical properties of the plates tested, in light of the loads transmitted across the native wrist, all plate constructs met the anticipated demands. It seems clear that fracture configuration, screw placement, cost, and surgeon familiarity with instrumentation should take priority in selecting a plating system for distal radius fracture treatment. CLINICAL RELEVANCE: This study provides further information to surgeons regarding the relative strengths of different plate options for the treatment of distal radius fractures.

Ultra-small cobalt particles embedded in titania by ion beam synthesis: Additional datasets including electron microscopy, neutron reflectometry, modelling outputs and particle size analysis.

This Data-in-brief article includes datasets of electron microscopy, polarised neutron reflectometry and magnetometry for ultra-small cobalt particles formed in titania thin films via ion beam synthesis. Raw data for polarised neutron reflectometry, magnetometry and the particle size distribution are included and made available on a public repository. Additional elemental maps from scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) are also presented. Data were obtained using the following types of equipment: the NREX and PLATYPUS polarised neutron reflectometers; a Quantum Design Physical Property Measurement System (14 T); a JEOL JSM-6490LV SEM, and a JEOL ARM-200F scanning transmission electron microscope (STEM). The data is provided as supporting evidence for the article in Applied Surface Science (A. Bake et al., Appl. Surf. Sci., vol. 570, p. 151068, 2021, DOI 10.1016/j.apsusc.2021.151068), where a full discussion is given. The additional supplementary reflectometry and modelling datasets are intended to assist future scientific software development of advanced fitting algorithms for magnetization gradients in thin films.

Influence of index finger proximal interphalangeal joint arthrodesis on precision pinch kinematics.

PURPOSE: To evaluate the impact of proximal interphalangeal (PIP) joint arthrodesis on the kinematics of precision pinch. METHODS: Eleven healthy subjects performed index finger-thumb pinch motions under 4 conditions: unrestricted thumb and index finger (CONTROL) and fusion of the PIP joint of the index finger in flexion of 30° (PIP30), 40° (PIP40), and 50° (PIP50). Fusion was simulated with metallic splints. Kinematics of the thumb and index finger were recorded with a motion capture system. RESULTS: Proximal interphalangeal joint fusion at 30°, 40°, and 50° restricted maximal pinch span between the thumb tip and index finger tip by 6%, 10%, and 14%, respectively. At the time of pulp contact, PIP fusion led to an increase in index metacarpophalangeal joint flexion angle for the PIP30 condition and an increase in variability of thumb tip location for the PIP50 condition. Furthermore, the dynamic coordination between joint angles throughout the movement was affected by PIP fusion. CONCLUSIONS: This study reports impairment in the kinematics of precision pinch associated with index finger PIP joint fusion. A PIP joint fusion at 40° to 50° leads to a more natural precision pinch posture, but it restricts the aperture and reduces pinch precision.