Analysis of clinical motor testing for adult patients with diagnosed ulnar neuropathy at the elbow

The strength of associations between ultrasound measures of upper limb muscle morphology and isometric muscle strength: An exploratory study

INTRODUCTION/AIMS

Assessing upper limb muscle strength is important for understanding health outcomes, such as daily function and mortality. Ultrasound (US) is increasingly used to evaluate muscle health, but the relationship between its measures of morphology and isometric strength has not been thoroughly explored in upper limb muscles. The aim of this study was to evaluate the associations between US morphological measures and isometric strength in functionally relevant upper limb muscles in healthy adults.

METHODS

Twenty-four healthy volunteers (30.0 ± 10.8 years) underwent B-mode, axial US scans of the first dorsal interosseus (FDI), flexor pollicis longus (FPL), biceps brachii (BB), brachialis (BR), and triceps brachii lateral head (TB). Participants performed corresponding maximal voluntary contractions (MVC), including first digit distal phalanx flexion, second digit abduction, and elbow flexion and extension. US images were segmented to obtain maximal muscle thickness (MT) and cross-sectional area (CSA).

RESULTS

Strong positive correlations were found between muscle strength and BB MT (r = .83; p < .001), BR CSA (r = .84; p < .001), and TB MT (r = .70; p < .001). Moderate positive correlations were found for strength and FDI CSA (r = .67; p < .001), FDI MT (r = .47; p < .05), FPL CSA (r = .54; p < .01), and FPL MT (r = .42; p < .05). No significant correlation was found between strength and BR MT (r = .16; p > .05).

DISCUSSION

Our data showed moderate-to-strong associations between US muscle morphology and strength, suggesting that US is likely a good biomarker for strength. However, its use is not "one size fits all." Future investigations should continue to assess this relationship in different muscles and expand the generalizability to clinical populations.

The hand diagram: A novel outcome measure following supercharged end-to-side anterior interosseous nerve to ulnar nerve transfer in severe compressive ulnar neuropathy

BACKGROUND

With advances in the surgical management for severe ulnar neuropathy with the introduction of the super charged-end-to-side (SETS) anterior interosseous nerve (AIN) to ulnar nerve transfer, a simple and reliable outcome measure is required. There is currently not "one" standardized outcome measure used to represent and compare results.

PURPOSE

To present the abduction hand diagram as a "novel", reproducible, and simple outcome measure for patients with severe ulnar neuropathy.

STUDY DESIGN

Retrospective case series.

METHODS

Nine patients with severe entrapment/compressive ulnar neuropathy at the elbow were reviewed. Clinical parameters included preoperative and postoperative abduction tracings, Medical Research Grade (MRC) muscle strength, key pinch strength, Disability of the Hand Arm and Shoulder (DASH) score, and crossed finger test. Electrodiagnostic data included change in compound muscle action potentials (CMAP) amplitude of the first dorsal interosseous (FDI), and abductor digiti minimi (ADM). Summary statistics were used for demographic and clinical data.

RESULTS

Average follow-up was 22.8 ± 9.3 months. At 18-months of follow up, 44% had ADM MRC grade 3 strength or higher, mean key pinch strength improved to 72 ± 19.3%, and mean DASH was 33 ± 28.7. There was a mean increase of 16.7 ± 9.1 mm and 31.5 ± 12 mm in total and summed hand abduction tracing measurements respectively.

CONCLUSIONS

Hand abduction tracings are a quantitative outcome measure to follow recovery over time for intrinsic hand function and can be used in patients with severe ulnar neuropathy following surgical intervention.

Ulnar nerve anteposition with adipofascial flap, an alternative treatment for severe cubital syndrome

BACKGROUND

Ulnar nerve entrapment at the elbow is the second most common cause of nerve entrapment in the upper limb. Surgical techniques mainly include simple decompression, decompression with anterior transposition and medial epicondylectomy.

METHODS

We performed decompression with anterior transposition and protected ulnar nerve by adipofascial flap (a random flap with radial based vascularization, harvested through the avascular plane of Scarpa's fascia. We analyzed patients who underwent ulnar nerve ante-position from 2015 to 2022 according to inclusion and exclusion criteria for a total of 57 patients. All patients included were graded on the McGowan's classification Messina criteria and the British Medical Research Council modified by Mackinnon and Dellon.

RESULTS

The average McGowan's score was 2.4 (± 0.6), Messina's criteria 91.2% indicated a satisfactory or excellent result, sensibility at 6 months was 98.5% S3 or more. A preferential technique has not yet been defined.

CONCLUSIONS

The adipofascial flap offers numerous advantages in providing a pliable, vascular fat envelope, which mimics the natural fatty environment of peripheral nerves and creates favorable micro-environmental conditions to contribute to neural regeneration via axon outgrowth.

Reliability and validity of the modified McGowan grade in patients with cubital tunnel syndrome

INTRODUCTION

This study aimed to assess the reliability and validity of the modified McGowan grading system and to determine its ability to distinguish the severity of cubital tunnel syndrome (CuTS) between the different grades.

MATERIALS AND METHODS

We prospectively enrolled 39 consecutive patients with CuTS from March 2018 to December 2020. Inter- and intra-observer reliability was assessed by two orthopaedic surgeons with a minimum 2-week interval using Cohen kappa coefficients. Validity was assessed by Spearman's correlation with objective clinical outcomes (grip strength, Semmes-Weinstein monofilament test [SWMT], static two-point discrimination [2PD], and motor conduction velocity [MCV]). In addition, the relationship between the grading system and patient-reported outcomes (Disabilities of the Arm, Shoulder and Hand score and Boston Questionnaire) was evaluated using Spearman's correlation. The ability to distinguish the severity between the different grades was assessed using the Kruskal-Wallis analysis.

RESULTS

The inter-observer kappa value was 0.54 and intra-observer kappa value was 0.59, which imply a moderate reliability. The modified McGowan grade had a moderate correlation with objective clinical outcomes (grip strength [r = - 0.350, p = 0.029], SWMT [r = 0.552, p < 0.001], 2PD [r = 0.456, p = 0.004], and MCV [r = - 0.394, p = 0.021]). However, patient-reported outcomes did not correlate with this grading system. Kruskal-Wallis analysis revealed significant differences between grades in terms of SWMT, 2PD, grip strength, and Boston Questionnaire functional score (p = 0.006, 0.025, 0.014, and 0.043, respectively); however, these differences were statistically significant only for a limited number of parts.

CONCLUSIONS

The modified McGowan grade has a moderate inter- and intra-observer reliability. This grading system moderately correlates with objective sensory-motor functions and MCV of patients with CuTS. However, the modified McGowan grade does not reflect the patient's perceived disabilities and has a weakness in distinguishing the severity of patients' conditions among the different grades.

Ulnar neuropathy at the elbow

At the elbow, the ulnar nerve (UN) may be the site of a static compression (by the cubital tunnel retinaculum and Osborne's ligament between the two heads of the flexor carpi ulnaris), or a dynamic compression, especially when the nerve is unstable (subluxation/dislocation outside the ulnar groove). The clinical basis for the diagnosis of ulnar neuropathy involves looking for subjective and objective signs of sensory and/or motor deficit in the ulnar nerve's territory in the hand, a pseudo-Tinel's sign, and doing manipulations to provoke UN irritation. The diagnosis is confirmed by electromyography and ultrasonography. In the early stages, patient education and elimination of flexion postures or repeated elbow flexion motions can provide relief. If this fails or signs of sensory and/or motor deficit are present, surgical treatment is proposed. If the nerve is stable, in-situ nerve decompression is typically done as the first-line treatment. If the nerve is unstable, anterior nerve transposition - generally subcutaneous - or more rarely, a medial epicondylectomy can be done. If surgical treatment fails, the patient's history is reviewed, and diagnostic tests can be repeated. Except in cases of a fibrotic scar, the main causes of failure are neuroma of a branch of the medial cutaneous nerve of the forearm, instability of the nerve and persistence of a compression point. In the latter two cases, surgical revision is justified and anterior nerve transposition or epicondylectomy can be proposed.

Cubital tunnel syndrome: Anatomy, clinical presentation, and management

Cubital tunnel syndrome is the second most common peripheral nerve compression seen by hand surgeons. A thorough understanding of the ulnar nerve anatomy and common sites of compression are required to determine the cause of the neuropathy and proper treatment. Recognizing the various clinical presentations of ulnar nerve compression can guide the surgeon to choose examination tests that aid in localizing the site of compression. Diagnostic studies such as radiographs and electromyography can aid in diagnosis. Conservative management with bracing is typically trialed first. Surgical decompression with or without ulnar nerve transposition is the mainstay of surgical treatment. This article provides a review of the ulnar nerve anatomy, clinical presentation, diagnostic studies, and treatment options for management of cubital tunnel syndrome.

Preworkshop knowledge of musculoskeletal anatomy of rheumatology fellows and rheumatologists of seven North, Central, and South American countries

OBJECTIVE

To report the baseline knowledge of clinical anatomy of rheumatology fellows and rheumatologists from Argentina, Chile, Ecuador, El Salvador, Mexico, the US, and Uruguay.

METHODS

The invitation to attend a workshop in clinical anatomy was an open call by national rheumatology societies in 4 countries or by invitation from teaching program directors in 3 countries. Prior to the workshop, a practical test of anatomic structures commonly involved in rheumatic diseases was administered. The test consisted of the demonstration of these structures or their function in the participant's or instructor's body. At one site, a postworkshop practical test was administered immediately after the workshop.

RESULTS

There were 170 participants (84 rheumatology fellows, 61 rheumatologists, and 25 nonrheumatologists). The overall mean ± SD number of correct answers was 46.6% ± 19.9% and ranged from 32.5-67.0% by country. Rheumatology fellows scored significantly higher than nonrheumatologists. Questions related to anatomy of the hand scored the lowest of the regions surveyed.

CONCLUSION

Rheumatology fellows and rheumatologists showed a deficit in knowledge of musculoskeletal anatomy that is of central importance in rheumatologic assessment and diagnosis. This gap may hinder accurate and cost-effective rheumatologic diagnosis, particularly in the area of regional pain syndromes. Presently, widespread use of musculoskeletal ultrasound (MSUS) by rheumatologists may be premature, since a key component of expert-level MSUS is the integration of an accurate knowledge of anatomy with the views obtained with the ultrasound probe.