Amadio, Peter C

ABSTRACT Based on anecdotal observation of fatty infiltration (FI) of the opponens pollicis (OPP) muscle in patients with thumb carpometacarpal (CMC) Osteoarthritis (OA), we sought to examine the association of FI with CMC OA. We reviewed 747 consecutive 3 T wrist magnetic resonance imaging (MRI) studies for evidence of FI in the thenar muscles. This population was divided into two cohorts based on radiographic analysis: a cohort without thumb CMC OA ( n = 440) and a second cohort with thumb CMC OA ( n = 307), staged according to the Eaton–Littler classification. Statistical analysis using logistic regression was performed to investigate clinical factors associated with the presence of FI in the thenar muscles. FI was present in 133 patients with CMC OA (43.3%). FI, when present, was located only in the OPP. We found no OPP FI in the cohort without CMC OA (440 patients). Among patients with CMC OA, increasing age, male sex and advanced OA stage were significantly associated with the presence of OPP FI. OPP FI is a frequent finding in CMC OA. This FI could affect the biomechanical function of the OPP. In the future, we plan to analyze clinical outcomes in CMC OA patients with and without FI, and more focused in vivo studies of OPP function. OPP FI could potentially affect the function and the stability of the thumb CMC joint in patients with CMC OA. Orthopaedic Research Society. Journal of Orthopaedic Research® 00:00–00, 2026.

ABSTRACT Tendon adhesion is a major complication following tendon reconstruction surgery in the hand. Previous studies showed that a combination of hyaluronic acid (HA) and gelatin, covalently bound to the tendon surface, can provide a durable gliding surface to reduce adhesions in animal models both in‐vitro and in‐vivo. We have developed a similar product using good manufacturing practice (GMP) standards, in preparation for use in humans. This study aimed to examine the frictional properties and elastic modulus of the Manufactured Tendon Lubricant (MTL) when applied to an extrasynovial canine peroneus longus (PL) tendon in‐vitro. Twenty PL tendons along with the 2nd and 5th digits from adult canine forepaws, were obtained (mean age: 12 months, weight: 35 kg) from animals sacrificed in Institutional Animal Care and Use Committee (IACUC) approved protocols. Tendons were treated either with the MTL or saline solution, as a control. Eight tendons from each group (MTL vs saline‐treated) underwent friction testing, using a previously described protocol, followed by indentation testing to assess tendon elastic modulus (a marker of successful crosslinking). Two tendons from each group were not tested and were sent for scanning electron microscopy (SEM). The MTL group had significantly ( p < 0.001) lower friction and gliding resistance as well as higher elastic modulus of the PL tendons, compared to the saline group. This study demonstrates that MTL provides lubricating effects and fixation to the tendon surface and may be suitable for human testing.

AbstractThis study aimed to compare the clinically established autologous extrasynovial tendon graft to a newly developed tissue‐engineered allograft (Eng‐allograft) in terms of functional outcomes following flexor tendon reconstruction in a canine model. The second and fifth flexor digitorum profundus (FDP) tendons from 16 dogs were transected and repaired in Zone II. After 6 weeks of cage activity, the repaired tendons were intentionally ruptured, creating a clinically relevant model for reconstruction. The re‐ruptured FDP tendons were then reconstructed using either the clinically standard autologous extrasynovial tendon graft or the Eng‐allograft, which had been revitalized with autologous bone marrow‐derived mesenchymal stem cells (BMSCs) and synovialized using carbodiimide derivatized synovial fluid (cd‐SYN). Following 12 weeks of postoperative rehabilitation, the functional outcomes of the surgical digits were evaluated. The Eng‐allograft group exhibited improved digital function, including lower digit work of flexion and reduced adhesion status, while maintaining similar tendon gliding resistance compared to the autograft group. However, the failure load of both the distal and proximal host/graft conjunctions in the Eng‐allograft group was significantly lower than that of the autograft group with higher graft rupture at the host−graft junction. In conclusion, the decellularized allogenic intrasynovial tendon, when revitalized BMSCs and synovialized with cd‐SYN, demonstrates positive effects on digital function improvement and adhesion reduction. However, the healing at both proximal and distal graft/host junctions is far lower than the autograft. Further research is needed to enhance the healing capacity of allograft conjunctions, aiming to achieve a comparable level of healing seen with autografts.

AbstractIntroduction/AimsUltrasound shear wave elastography (SWE) of the thenar muscles has the potential to provide a simple and noninvasive assessment of the severity of carpal tunnel syndrome (CTS), but its reliability is unknown. The purpose of this study was to assess the intra‐ and inter‐rater reliability of SWE measurements of the elastic modulus of individual thenar muscles, to assess their suitability for clinical application.MethodsFourteen healthy volunteers, seven male and seven female, participated in this study. The elastic modulus of the thenar muscles was measured with SWE, with two independent examiners to assess inter‐rater reliability. The first examiner also performed a second measurement after an interval of least 1 day to assess intra‐rater reliability. Reliability was evaluated using an intraclass correlation coefficient (ICC) and 95% confidence interval (CI).ResultsFor the abductor pollicis brevis (APB) and opponens pollicis (OPP), the CI of ICC in intra‐rater reliability was 0.47–0.85 and 0.56–0.88, respectively. The CI of ICC in inter‐rater reliability was 0.27–0.78 for the APB and 0.22–0.76 for the OPP. The ICCs of intra‐ and/or inter‐rater reliability of other thenar muscles were less than 0.5.DiscussionIn this study, SWE evaluations of thenar muscles were quite variable in terms of their reliability. A larger study will be needed to determine the source of this variability, improve reliability, and assess the value of SWE in the evaluation of the severity of CTS.

ObjectivesThe mobility (transverse movement) of the median nerve (MN) is decreased in patients with carpal tunnel syndrome and can be measured noninvasively by ultrasound. To date, there are few prognostic features to help predict the outcome of 2 commonly performed treatments: surgical carpal tunnel release and corticosteroid injection. This study aimed to assess the changes in nerve mobility after the intervention and to correlate this with treatment and the disease severity.MethodsA total of 181 patients with carpal tunnel syndrome with different electrophysiologic severities were recruited and assessed by dynamic ultrasound scanning of the MN before and after treatment. The dynamic ultrasound images were collected while the patients performed finger and wrist flexion.ResultsFor both injection and carpal tunnel release, the nerve displacement increased with wrist flexion, from a mean ± SD of 7.0 ± 2.4 to 7.9 ± 2.7 mm (P < .005). Patients who underwent surgery showed greater improvement (P < .005) in nerve mobility compared to those who underwent injection. We also observed that the increase in nerve mobility was predominantly in patients with more nerve damage at baseline.ConclusionsThis study shows that the dynamic behavior of the MN changes in response to treatment and lays a foundation for future studies to assess the prognostic potential of nerve mobility measurement.