A New Surface Landmark for Thumb Digital Nerve Bifurcation: A Cadaveric Study.

PURPOSE: The radial and ulnar thumb digital nerves are critical for tactile sensation and dexterity in the hand. This cadaveric study sought to validate a surface landmark for the bifurcation of the thumb radial digital nerve (RDN) and ulnar digital nerve (UDN). METHODS: We used 24 fresh-frozen cadaveric specimens for dissections. With the thumb placed in the plane of the palm and fully radially abducted, the index finger metacarpophalangeal joint was flexed to 90°. Then, while keeping the distal interphalangeal joint straight, the proximal interphalangeal joint was flexed until the fingertip contacted the thenar eminence to identify the point of bifurcation. We made a U-shaped incision and identified the bifurcation of the thumb RDN and UDN. The point of bifurcation was measured from the ulnar- and proximal-most aspects of the incision. RESULTS: The bifurcation of the thumb RDN and UDN was consistently identified within the U in 22 of 24 specimens (92%). In 16 specimens, the index RDN was also identified either trifurcating with the thumb RDN and UDN or branching from a common digital nerve of index RDN and thumb UDN. Most bifurcation points were found directly along the ulnar and proximal edge of the incision. Two specimens contained a bifurcation point 2 mm ulnar to the ulnar limb of the U. CONCLUSIONS: The bifurcation U is a consistent landmark for the thumb RDN and UDN point of bifurcation. The variable branching patterns in this region confirms the importance of thorough clinical examination with penetrating injuries to the thenar eminence. CLINICAL RELEVANCE: This surface anatomic landmark for the thumb RDN and UDN bifurcation may aid in preventing iatrogenic injuries during elective procedures and identifying at-risk structures during penetrating injuries to the palm.

The Effect of Simulated Total Distal Interphalangeal Joint Stiffness on Grip Strength.

PURPOSE: Production of a functional grip pattern requires the concerted action of numerous structures within the hand. This study quantifies the effect of total distal interphalangeal joint (DIPJ) stiffness to grip strength. METHODS: Fifty (25 men, 25 women, 100 hands) individuals with a mean age of 38 years (range: 17-69 years) were recruited. Exclusion criteria included history of previous upper limb injury, neuropathies, or systemic disease. Custom thermoplastic orthoses were used to splint participants' DIPJ in full extension simulating stiffness. Grip strength before and after splinting was measured using a calibrated Jamar dynamometer. Data were analyzed using paired and independent sample t tests and 2 × 2 repeated-measures analysis of variance with hand dominance and configuration (splinted or unsplinted) as within-subject factors. RESULTS: Restriction of DIPJ flexion led to a 20% decrease in grip strength (P < .001). There was no significant difference in this decrease between dominant and non-dominant hands. Univariate analysis did not demonstrate any interaction between hand dominance and testing configuration. Post hoc analysis revealed no statistical difference in baseline grip strength between the dominant and non-dominant hands. Furthermore, men had significantly stronger grip strength than women in all configurations (P < .001). CONCLUSIONS: Flexion at the DIPJ contributes significantly to grip strength, and stiffness at this joint greatly limits functional capabilities of the hand. This necessitates the need for targeted rehabilitation in DIPJ injuries to minimize adverse effects on grip strength.

OBJECTIF: Pour produire un schéma de préhension fonctionnel, il faut l'action concertée de multiples structures de la main. La présente étude quantifie l'effet de la raideur de toute l'articulation interphalangienne distale (AIPD) sur la force de préhension. MÉTHODOLOGIE: Les chercheurs ont recruté 50 personnes (25 hommes, 25 femmes, 100 mains) d'un âge moyen de 38,28 ans (plage de 17 à 69 ans). Les critères d'exclusion incluaient des antécédents de blessure d'un membre supérieur, de neuropathie ou de maladie systémique. Les chercheurs ont utilisé des orthèses thermoplastiques sur mesure pour mettre une attelle sur l'AIPD en pleine extension des participants, afin de simuler la raideur. Ils ont mesuré la force de préhension avant et après la pose de l'attelle à l'aide d'un dynanomètre Jamar calibré. Ils ont évalué les données à l'aide de tests de Student appariés et indépendants et de l'analyse de variance à mesures répétées 2×2 et se sont servis de la dominance de la main et de la configuration (avec ou sans attelle) comme facteurs individuels. RÉSULTATS: La restriction de la flexion de l'AIPD suscitait une diminution de la force de préhension de 20 % (P < 0,001). Il n'y avait pas de différence significative entre les mains dominantes et non dominantes. L'analyse univariée n'a pas démontré d'interaction entre la dominance de la main et la configuration des tests. L'analyse a posteriori n'a révélé aucune différence statistique de la force de préhension entre les mains dominantes et non dominantes en début d'étude. De plus, les hommes avaient une beaucoup plus grande force de préhension que les femmes dans toutes les configurations (P < 0,001). CONCLUSIONS: La flexion de l'AIPD contribue de manière significative à la force de préhension, et la raideur de l'articulation limite considérablement la capacité fonctionnelle de la main. Ainsi, il faut prévoir une réadaptation ciblée des lésions de l'AIPD pour en réduire le plus possible les effets indésirables sur la force de préhension.

Contribution of the ulnar digits to grip strength.

PURPOSE: To determine the contribution of ulnar digits to overall grip strength. SUBJECTS: Fifty individuals (25 men and 25 women; 100 hands) with a mean age of 35.6 years (range 19 to 62 years) were tested. Exclusion criteria included previous history of hand injuries, entrapment neuropathies and systemic diseases. METHODS: Ethics approval was granted before testing. A calibrated Jamar dynamometer (Lafayette Instrument Company, USA) was used to test subjects in three configurations: entire hand - index, middle, ring and little fingers; index, middle and ring fingers; and index and middle fingers. Little and ring fingers were excluded using generic hand-based finger splints. The order of testing was kept constant, and subjects were tested three times on each hand for each configuration. The average of the three trials at each configuration was recorded. Subjects received 1 min of rest between each testing configuration. The data were analyzed using a 3×2 repeated measures ANOVA with hand dominance and configuration as the within-subject factors, followed by two independent sample t tests to compare flexor digitorum superficialis (FDS) independence and FDS nonindependence on right and left hand grip strength measurements in the index, middle, ring and little condition. RESULTS: Univariate results demonstrated that grip strength was significantly predicted by the interaction between hand dominance and configuration, while the parsing of the interaction term demonstrated greater grip strength across all levels of configuration for the dominant and nondominant hand. There were no significant differences between FDS independence and FDS nonindependence for either hand on grip strength. DISCUSSION: The results indicate a significant decrease in grip strength as ulnar fingers were excluded. Furthermore, exclusion of the little finger has differing effects on the grip strength of the dominant and nondominant hands - the dominant hand had a greater loss of strength with the little finger excluded than the nondominant hand. CONCLUSIONS: The ulnar two digits play a significant role in overall grip strength of the entire hand. In the present study, exclusion of the ulnar two digits resulted in a 34% to 67% decrease in grip strength, with a mean decrease of 55%. Exclusion of the little finger from a functional grip pattern decreased the overall grip strength by 33%. Exclusion of the ring finger from a functional grip pattern decreased the overall grip strength by 21%. It is clear that limitation of one or both of the ulnar digits adversely affects the strength of the hand. In addition, there was no significant difference between grip strength of FDS-independent and FDS-nonindependent subjects for either hand.

The use of Botox in interventional radiology.

Botox (Botulinum toxin A) has wide public recognition as a cosmetic agent. It has also established a firm foothold within the medical community for the treatment of a wide range of myospastic disorders. With imaging guidance, interventional radiologists can deliver this medication to a variety of otherwise difficult to reach targets with high accuracy and with minimal complications. We illustrate the use of Botox in interventional radiology by describing our fluoroscopic technique for the treatment of piriformis syndrome. The key to successful Botox therapy of myospastic disorders is accurate clinical diagnosis. Excellent communication and rapport with the referring clinicians is therefore essential to maximize the likelihood of a successful outcome. The range of services offered by interventional radiologists continues to evolve. With the recent growth of endovenous treatment for varicose veins, some have found it necessary to provide sclerotherapy for spider veins. As patients become accustomed to receiving these cosmetic treatments from interventionalists, they may come to us for advice about other esthetic therapy. The idea of some interventional radiologists adding cosmetic medicine to their practice should, therefore, not seem unreasonable. We illustrate the use of Botox for facial rejuvenation by describing our technique for the treatment of glabelar (frown) lines. Before entering into this type of practice, it is critical to obtain adequate and appropriate training for each cosmetic intervention. If possible, the interventionalist should seek to establish a mentor relationship with someone highly experienced in cosmetic medicine.

Outcomes in carpal tunnel syndrome: symptom severity, conservative management and progression to surgery.

PURPOSE: This study investigated the relationship between severity of symptoms and success of nonoperative and operative treatment in patients with carpal tunnel syndrome (CTS). METHODS: An observational cohort study regarding the management of CTS was conducted. Thirty patients referred to a tertiary hand centre with a diagnosis of CTS were prospectively followed. Twenty-five of the patients (47 affected hands) were available for long-term follow up to determine management outcomes. Self-report symptoms and physical impairments were assessed and documented at baseline, 6 weeks, and 12 weeks using the CTS Severity Score (SSS), the Disability-Shoulder, Arm and Hand Score (DASH), and the Levine Functional Score. Longer-term follow-up was conducted to identify status on outcome measures and whether patients proceeded to surgery. RESULTS: Those who proceeded to surgery (n = 27/47 hands) had higher initial CTS SSS and DASH scores and also maintained higher scores compared to those who improved with conservative management (p < 0.05). Improvements occurred in the SSS (P < 0.0001), Functional Score (P < 0.001), and DASH score (P < 0.05) following surgery in the patients resistant to conservative management. Recovery of grip and dexterity was less satisfactory. DISCUSSION: This study suggests that the SSS is useful in the triage of patients on surgical wait-lists as patients with high initial scores or failure to change in short-term follow-up are likely to proceed to surgical release. Despite prolonged symptoms and previous treatment, patients with lower SSS scores had moderate success with a second trial of conservative management.

Individual finger strength: are the ulnar digits "powerful"?

This study determined the test-retest reliability of a grip device that measures the contribution of individual fingers to grip strength and described the pattern of contribution in subjects without hand pathology. Subjects repeated a set of three maximal grip efforts on two occasions separated by two to seven days. Intraclass correlation reliability coefficients were high (>0.75) for eight out of ten strength measures. The percentage contributions of the index, middle, ring, and small fingers to grip were approximately 25%, 35%, 25%, and 14%, respectively. Grip and finger strengths were highly correlated. Anthropometric measures of body size or finger length were moderately correlated with strength measures. These data suggest that there is a predictable pattern by which individual fingers contribute to overall grip strength, which is partially related to body size. The ulnar side of the hand contributes to the smaller proportion of overall grip (approximately 60% radial, 40% ulnar). The clinical utility of finger strength measures should be explored.

Pain and disability reported in the year following a distal radius fracture: a cohort study.

BACKGROUND: Distal radius fractures are a common injury that cause pain and disability. The purpose of this study was to describe the pain and disabilities experienced by patients with a distal radius fracture in the first year following fracture. METHODS: A prospective cohort study of 129 patients with a fracture of the distal radius was conducted. Patients completed a Patient-rated Wrist Evaluation at their baseline clinic visit and at 2, 3, 6 and 12 months following their fracture. The frequency/severity of pain and disabilities reported was described at each time point. RESULTS: The majority of patients experienced mild pain at rest and (very) severe high levels of pain with movement during the first two-months following distal radius fracture. This time is also associated with (very) severe difficulty in performing specific functional activities and moderate to severe difficulty in four domains of usual activity. The majority of recovery occurred within six-months, but symptoms persisted for a small minority of patients at one-year following fracture. Patients had the most difficulty with carrying ten pounds and pushing up from a chair. Resumption of usual personal care and household work preceded, and was more complete, than work and recreational participation. CONCLUSIONS: This study demonstrated that the normal course of recovery following a distal radius fracture is one where severe symptoms subside within the first two-months and the majority of patients can be expected to have minimal pain and disability by six-months following fracture. This information can be used when planning interventions and assessing whether the progress of a patient is typical of other patients.

Beta-catenin expression in Dupuytren's disease: potential role for cell-matrix interactions in modulating beta-catenin levels in vivo and in vitro.

Dupuytren's disease (DD) is a superficial fibromatosis of the hand. Although the molecular mechanisms responsible for this disease are unknown, recent studies suggest that beta-catenin may be a key factor involved in fibromatosis. In this study, we analysed the in vivo and in vitro expression levels of beta-catenin in DD, using surgical specimens and primary cell lines. Although no somatic mutations (exon 3) of beta-catenin were detected, Western blot analysis revealed high levels of beta-catenin in diseased palmar fascia, and low to undetectable levels of beta-catenin in patient-matched normal palmar fascia. Immunohistochemistry analysis showed high levels of beta-catenin expression within the disease fascia, as well as cytoplasmic and nuclear accumulations of the protein. Immunoprecipitation of beta-catenin from seven patient lesions showed the protein to be tyrosine phosphorylated. Lastly, Western analysis of three patient-matched (disease and normal fascia) primary cell cultures showed significantly elevated levels of beta-catenin in disease cells cultured in three-dimensional collagen lattices. This is the first extensive in vivo and in vitro characterization of beta-catenin in DD, and the first to suggest that the extracellular matrix may play an important role in modulating beta-catenin stability in DD.

Endoscopic versus open carpal tunnel release: a randomized trial.

PURPOSE: This study compared the outcomes in patients assigned to either endoscopic carpal tunnel release (ECTR) or traditional open carpal tunnel release (OCTR). METHODS: An unbalanced randomized clinical trial (91 endoscopic, 32 open) was conducted. Short-term and long-term outcomes were evaluated by a blinded assessor. The primary outcome measures were symptom severity measured on a self-report scale and nerve/vascular complications. Secondary outcomes included the McGill pain questionnaire, grip strength, pinch strength, sensory threshold (NK PSSD device, NK Biotechnical Corp, Minneapolis, MN), and time to return to work. RESULTS: Both groups improved on all outcomes. No differences were observed in primary outcomes between the groups at either baseline or follow-up at 1 week, 6 weeks, or 12 weeks after surgery. No significant complications occurred in either group. Grip strength and pain were significantly better at 1 and 6 weeks in the endoscopic group although differences dissipated by 12 weeks. No significant differences occurred in other secondary outcomes. Long-term satisfaction was lower in the endoscopic group, attributable to a 5% rate of re-operation. Lower rates of endoscopic release have occurred at our center once these results were available to surgeons and patients. CONCLUSIONS: No substantive difference in benefit was shown for these 2 methods of carpal tunnel release.

Patient versus injury factors as predictors of pain and disability six months after a distal radius fracture.

A prospective cohort of 120 patients with distal radius fractures completed a baseline evaluation that determined their age, sex, education level, injury compensation status, AO fracture type, prereduction radial shortening, and postreduction radial shortening. Six months later patients self-reported pain and disability using the Patient-Rated Wrist Evaluation, and were tested for physical impairment (grip, wrist range of motion, and dexterity). Univariate and forward stepwise regression analyses agreed that the most influential predictor of pain and disability at 6 months was injury compensation. Patient education level and prereduction radial shortening also contributed predictive information (R squared = 25%). Wrist impairment was moderately correlated with patient reported pain and disability (r = 0.50). Both impairment and disability measures are required to fully describe outcomes. Further work is required to delineate additional factors that contribute to outcome.

Refracture rate after plate removal from the radial metaphysis.

OBJECTIVES: To document the refracture rate after removal of internal fixation at the metaphyseal region of the distal radius and to compare this rate to that associated with diaphyseal plate removal reported in the literature. DESIGN: A chart review with telephone follow-up. SETTING: Three tertiary care hospitals (in Ottawa, Burlington, Vt., and London, Ont.). PATIENTS: Fifty-three patients (54 radii) underwent elective removal of internal fixation of the distal radius after distal metaphyseal procedures. The mean follow-up was 46.8 months. MAIN OUTCOME MEASURE: The refracture rate. RESULTS: No refractures were reported after plate removal, and the overall complication rate was minimal. CONCLUSIONS: The refracture rate at the metaphvsis of the radius after plate removal is lower than the rate after diaphyseal plate removal reported in the literature.