Innervation patterns of thumb trapeziometacarpal joint ligaments

Morphological and Mechanical Property Differences in Trapeziometacarpal Ligaments of Healthy and Osteoarthritic Female Joints

PURPOSE

To identify changes in morphological and mechanical properties in the volar ligament complex (VLC), dorsoradial ligaments (DRL), and posterior oblique ligaments (POL) in healthy and osteoarthritic female trapeziometacarpal (TMC) joints.

METHODS

Twenty-four fresh-frozen female cadaveric TMCs were separated into (1) younger healthy/early-stage osteoarthritic, (2) elder healthy/early-stage osteoarthritic, and (3) advanced-stage osteoarthritic groups based on age and Eaton-Littler grading. Stress relaxation and load-to-failure testing were performed to characterize mechanical tensile properties. Light imaging and scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS) were performed to further assess enthesis structural integrity.

RESULTS

The VLC in advanced-stage osteoarthritic TMCs had attenuated mechanical properties in stress relaxation experiments compared to the elder healthy/early-stage osteoarthritic specimens: Young's modulus at 20% strain (P = 0.044), instantaneous (P = 0.023), relaxed (P = 0.017) moduli. VLCs in advanced-stage osteoarthritic TMCs also had significantly lower properties in the load-to-failure experiments compared to the younger healthy/early-stage osteoarthritic specimens: stiffness (P = 0.048), ultimate load (P = 0.017), toughness (P = 0.003). Light and SEM/EDS imaging revealed partial detachment and loss of enthesis mineral gradient at VLC metacarpal insertion in advanced-stage osteoarthritic specimens. There were no mechanical or structural changes in the DRL and POL between experiment groups.

CONCLUSION

VLC morphological and mechanical properties deteriorate across progressively severe osteoarthritis classifications while the DRL and POL remain unchanged. The attenuated mechanical properties of VLCs in advanced-stage osteoarthritic TMCs can be explained by ligament degradation as evidenced by partial detachment and loss of mineral gradient at the metacarpal insertion.

The multidirectional roles of the anterior oblique ligament and dorsoradial ligament of the thumb carpometacarpal joint

The multidirectional biomechanics of the thumb carpometacarpal (CMC) joint underlie the remarkable power and precision of the thumb. Because of the unconfined nature of thumb CMC articulation, these biomechanics are largely dictated by ligaments, notably the anterior oblique ligament (AOL) and the dorsoradial ligament (DRL). However, the rotational and translational stabilizing roles of these ligaments remain unclear, as evidenced by the variety of interventions employed to treat altered pathological CMC biomechanics. The purpose of this study was to determine the effects of sectioning the AOL (n = 8) or DRL (n = 8) on thumb CMC joint biomechanics (rotational range-of-motion [ROM] and stiffness, translational ROM) in 26 rotational directions, including internal and external rotation, and in eight translational directions. Using a robotic musculoskeletal simulation system, the first metacarpal of each specimen (n = 16) was rotated and translated with respect to the trapezium to determine biomechanics before and after ligament sectioning. We observed the greatest increase in rotational ROM and decrease in rotational stiffness in flexion directions and internal rotation following DRL transection and in extension directions following AOL transection. The greatest increase in translational ROM was in dorsal and radial directions following DRL transection and in volar directions following AOL transection. These data suggest the AOL and DRL play complementary stabilizing roles, primarily restraining translations in the direction of and rotations away from the ligament insertion sites. These findings may inform future interventions or implant designs for pathological CMC joints.

Automated analysis of trapeziometacarpal joint kinematics using four-dimensional computed tomography

The aim of this study was to develop an automated approach model to define in vivo kinematics of the trapeziometacarpal (TMC) joint using four-dimensional computed tomography. A total of 15 healthy volunteers were included and their TMC joint kinematics were studied during a retropulsion-opposition-retropulsion movement. We used cardan angles estimated from transformation matrices using a ZYX-decomposition and analysed the motion of the thumb metacarpal relative to the trapezium, the thumb metacarpal relative to the index metacarpal, and the trapezium relative to the index metacarpal. The study also included an analysis of the joint hysteresis effect and a joint proximity model that estimated the joint contact area during a retropulsion-opposition-retropulsion movement. The automated approach significantly decreased the time needed to analyse each case and makes this model applicable for further research on TMC kinematics.

Trapeziometacarpal joint imaging: Normal high-resolution MRI, US and CT compared with cadaveric specimens and pathological imaging findings

INTRODUCTION

The trapeziometacarpal (TMC) joint is a complex joint, whose anatomy and function are different from the metacarpophalangeal joints of the long fingers. The stability of this joint is ensured at three levels by multiple structures: osteochondral, capsulo-ligamentous, and musculo-tendinous. The anatomical and biomechanical structures ensuring the stability of the TMC joint are perfectly evaluated on magnetic resonance imaging (MRI), with a high degree of confidence. All described ligaments are anatomically visible and perfectly assessed on MRI and ultrasound (US): the dorsoradial ligament, the posterior oblique ligament, the intermetacarpal ligament, the ulnar collateral ligament, the two bundles of the anterior oblique ligament (break ligament), as well as the superficial anterior oblique and deep anterior oblique ligaments.

METHODOLOGY

This educational review assesses the TMC joint anatomy using high-field MRI and US compared with cadaveric specimens as well the biomechanics of this joint. In addition, it highlights pathological patterns of traumatic (sprain, dislocation, and fractures) and degenerative diseases.

RESULTS AND CONCLUSION

Knowledge of TMC joint anatomy is crucial to the radiologists' understanding and assessment of various traumatic and degenerative pathologies, and thus helps clinicians and surgeons choose the appropriate treatment.

Wrist proprioception-An update on scientific insights and clinical implications in rehabilitation of the wrist

The field of wrist proprioception, as it relates to rehabilitation and surgery, has gone through a period of intense growth in the past decade. From being primarily focused on the function of the joint and ligaments in patients with wrist trauma or after wrist surgery, the understanding is now that of a greater complexity in treating not just the wrist but the hand and arm as a whole. Proprioception is derived from the Latin words "proprius" - belonging to (oneself) and "-ception" to sense. In other words, how to sense ourselves. To have a complete sense of self, multiple sensory afferents originating from joints, ligaments, muscles, tendons, nerves, skin, vision, and hearing work together to orchestrate a balanced integration of sensorimotor functions, with the true goal to perceive and adapt to the physical world around us. In this update on wrist proprioception, we review current developments in the understanding of proprioception, with an implication for our everyday work as hand therapists and hand surgeons. Each contributing sense-joint, ligaments, muscles, skin, and brain-will be reviewed, and the clinical relevance will be discussed. An updated wrist rehabilitation protocol is proposed where the therapist is guided to rehabilitate a patient after wrist trauma and/or surgery in 4 stages: (1) basic hand and wrist rehabilitation with a focus on reducing edema, pain, and scar formation; (2) proprioception awareness to improve the sense of joint motion and position; (3) conscious neuromuscular rehabilitation where isometric exercises of muscles that are beneficial for a particular injury are promoted, whereas others that are potentially harmful are avoided; and (4) unconscious neuromuscular rehabilitation with training of the reflex and joint protective senses.

Ligament reconstruction in thumb carpometacarpal joint instability: A systematic review

In thumb carpometacarpal (CMC) instability, laxity of the ligaments surrounding the joint leads to pain and weakness in grip and pinch strength, which predisposes the patient to developing CMC joint arthritis. Recent advancements in joint anatomy and kinematics have led to the development of various surgical reconstructive procedures. This systematic review outlines the available ligament reconstruction techniques and their efficacy in treating nontraumatic and nonarthritic CMC instability. Additionally, we aimed to provide evidence which specific ligament reconstruction technique demonstrates the best results. Four databases (Embase, MEDLINE, Web of Science, and Cochrane Central) were searched for studies that reported on surgical techniques and their clinical outcomes in patients with nontraumatic and nonarthritic CMC instability. Twelve studies were analyzed for qualitative review, including nine different surgical ligament reconstruction techniques involving two hundred and thirty thumbs. All but one of the reported techniques improved postoperative pain scores and showed substantial improvement in pinch and grip strength. Complication rates varied between 0% and 25%. The included studies showed that ligament reconstruction effectively alleviated the patients' complaints regarding pain and instability, resulting in overall high patient satisfaction. Nevertheless, drawing definitive conclusions regarding the superiority of any ligament reconstruction technique remains challenging owing to the limited availability of homogeneous data in the current literature.

Joint capsule innervation does not explain the difference in symptoms between scaphotrapezial and trapeziometacarpal osteoarthritis

OBJECTIVES

Peritrapezial osteoarthritis (OA) includes scaphotrapezial and trapeziometacarpal OA. In clinical practice, scaphotrapezial OA seems better tolerated than trapeziometacarpal OA, with fewer complaints and better tolerance. The difference in pain could be linked to a difference in joint capsule innervation, perhaps with fewer nerve fibers in the scaphotrapezial than the trapeziometacarpal joint.

MATERIALS AND METHODS

We performed a histologic evaluation of these two joints to compare their respective innervation in 17 cadaveric specimens with peritrapezial OA. Radiographic scoring confirmed the presence of peritrapezial OA. Mean Kellgren-Lawrence score was 2.2 ± 1.1 in the trapeziometacarpal joint and 1.5 ± 0.7 in the scaphotrapezial joint (p = 0.08).

RESULTS

There was no difference between scaphotrapezial and trapeziometacarpal joints in number of neurofilaments: 5.2 ± 3.9 and 4.4 ± 4.5, respectively (p = 0.20). A significant difference was found in S100 staining (myelinated structures), with a higher rate in the scaphotrapezial joint: 11.8 ± 7.5 vs 6.6 ± 5.2 (p = 0.005).

CONCLUSION

The present study suggests that lower tolerance of trapeziometacarpal OA is not due to a difference in joint capsule innervation. On the contrary, we found a higher rate of myelinated tissues in the scaphotrapezial joint. These results suggested other pain pathways to explain clinical observations.

Effectiveness of proprioception training in functional recovery of thumb osteoarthritis. Single, multicenter, non-blind randomized clinical trial

BACKGROUND AND OBJECTIVES

Osteoarthritis at the base of the thumb (CMC-1 OA) is a pathology that mainly affects postmenopausal women. The main symptoms including pain, decreased hand-thumb strength and fine motor capacity. Although a proprioceptive deficit has already been demonstrated in people with CMC-1 OA, there is insufficient evidence regarding the effects of proprioceptive training. The main objective of this study is to determine the effectiveness of proprioceptive training in functional recovery.

MATERIALS AND METHODS

A total of 57 patients were included in the study, 29 in the control group and 28 in the experimental group. Both groups underwent the same basic intervention programme, but the experimental group included a proprioceptive training protocol. Variables of the study were pain (VAS), perception of occupational performance (COMP), sense position (SP) and force sensation (FS).

RESULTS

Statistically significant improvement was observed in the experimental group in pain (p < .05) and occupational performance (p < .001) after 3 months of treatment. No statistical differences were found in sense position (SP) or sensation of force (FS).

DISCUSSION AND CONCLUSIONS

The results concord with previous studies focussing on proprioception training. The incorporation of a proprioceptive exercise protocol reduces pain and significantly improves occupational performance.

Thumb Carpometacarpal Stabilization With a Dorsal Capsule Repair Augmented With an Internal Brace

Optimal surgical treatment of first carpometacarpal joint instability remains a subject of debate. Consensus on thumb carpometacarpal stability originating with the dorsoradial ligamentous complex has shifted reconstruction techniques towards stabilization dorsally. We describe a dorsal stabilization technique with internal brace augmentation of the dorsoradial ligamentous complex. A single fellowship-trained hand surgeon treated 10 women, average age 34 years (range, 21 to 52 y) and 1 man, age 34 years, between 2019 and 2022. Average patient follow-up was 2 years. Patient satisfaction was high. Further trials are needed to determine whether the procedure will prevent or delay the presentation of thumb carpometacarpal arthrosis.

Proprioceptive Neuromuscular Facilitation Protocol for Thumb Osteoarthritis: A Pilot Study

BACKGROUND

Osteoarthritis (OA) of the thumb carpometacarpal (CMC) joint often presents with joint instability and proprioceptive deficits. Proprioception has been found to play an important role in the rehabilitative process. The purpose of this study was to evaluate the effectiveness of a proprioceptive training program on pain and function in individuals with early-stage thumb Carpometacarpal joint OA.

METHODS

A double-blind experimental trial using a 2-group pretest/posttest design was used in this pilot study. Participants had a diagnosis of grade I and II thumb CMC joint OA in their dominant hand and a pain rating of >4/10 on Visual Analogue Scale. Participants received either standard treatment (control group) or standard treatment plus a proprioceptive training program (experimental group). Outcome measures were lateral pinch strength, pain intensity during activities, and proprioceptive response via joint position sense (JPS) testing.

RESULTS

Twelve individuals (average age of 66.25 years) participated. Both groups had a statistically significant decrease in pain and increase in lateral pinch strength, all occurring with a large effect size but no statistically significant difference between groups. The experimental group experienced a large effect size for JPS testing, whereas the control group experienced a trivial effect size, and there was a statistically significant difference between groups for JPS testing.

CONCLUSIONS

Individuals who completed the proprioceptive training program in this study had an improvement in proprioceptive functioning. This program shows potential for routine inclusion in hand therapy for thumb CMC joint OA; however, additional high-level studies with larger sample sizes are required.

Arthroscopic Assisted Treatment of Combined Trapezium and Bennett Fracture-Dislocation

Trapezium fractures are unusual; however, they represent the third most frequent fracture of the carpal bones. As they usually follow a high-energy trauma, they are associated with distal radius, Bennett, or Rolando fractures in 80% of cases. Traditional treatment options include, closed reduction and percutaneous pinning, or open reduction and internal fixation. To minimize the additional surgical trauma, an arthroscopic technique has been developed for safe, minimally invasive management of complex injuries of the first carpo-metacarpal joint. Intra-articular dislocated fracture fragments are reduced under direct visualization and fixed through small incisions. Limiting additional surgical damage on the carpo-metacarpal joint ligaments, capsule, and other soft tissues around the fracture preserves the blood supply to fracture fragments and also the proprioceptive system, which is key for the dynamic stability of such a hypermobile joint. This report confirms that the procedure is feasible, and a complete functional recovery can be expected with reduced postoperative rehabilitation.

Anatomical study for elucidating the stabilization mechanism in the trapeziometacarpal joint

To determine the pathogenesis of trapeziometacarpal (TMC) joint instability, which leads to osteoarthritis, we investigated the anatomical relationships among the surrounding ligaments, muscles (first dorsal interosseous [FDI] and opponens pollicis [OPP]), and joint capsule. We examined the bone morphology and cortical bone thickening in 25 cadaveric thumbs using micro-computed tomography and performed macroscopic and histological analyses. The dorsal trapezium had a tubercle with cortical bone thickening, corresponding to the attachment of the FDI aponeurosis intermingled with the joint capsule. Radially, the thin joint capsule was observed to underlie the muscular part of the OPP. Therefore, the dorsal ligaments, which have been previously considered static stabilizers, could be interpreted as parts of the capsuloaponeurotic complex consisting of the FDI aponeurosis and joint capsule. In the radial aspect, muscular OPP activation may be essential for TMC joint stabilization. Our findings may contribute to the appropriate management of TMC osteoarthritis.

Anatomical 3 Ligaments Reconstruction for Symptomatic Thumb Carpometacarpal Joint Instability

Thumb carpometacarpal (CMC) joint instability is thought to be a debilitating disorder and, if left untreated, develops joint persistent synovitis and osteoarthritis. In this study, we report a novel surgical technique reconstructing the anterior oblique ligament, the dorsoradial ligament, and the intermetacarpal ligament simultaneously using both the transverse carpal ligament, and the palmaris longus tendon. Six patients with a mean age of 44 years showing no osteoarthritic changes by the radiographical examination underwent our anatomical three ligaments reconstruction for persistent painful thumb CMC joint instability. Clinical results with the mean follow-up of 20 months demonstrated that the pain was subjectively improved in all patients, both the grip and the pinch strength were increased significantly and good functional motion of the thumb could be observed after the operation. These findings indicated that our surgical procedure could be one option of treatment of the symptomatic CMC joint instability in early-stage arthritis.

Clinical effects of proprioceptive thumb exercise for individuals with carpometacarpal joint osteoarthritis: A randomized controlled trial

STUDY DESIGN

Randomized Control Trial.

INTRODUCTION

Thumb CMC joint OA is a common diagnosis. Currently there is no evidence available to under if proprioceptive neuromuscular training is an effective intervention for this population.

PURPOSE OF THE STUDY

To establish the effectiveness of a proprioceptive training program as a complementary therapy for patients with thumb CMC joint OA.

METHODS

Standard conservative thumb CMC joint OA treatments were received by both the control (n = 26) and experimental groups (n = 26) for a period of 12 weeks. The experimental group received a proprioceptive training program during the same intervention period. Outcome measures included severity of pain with activity according to the numerical rating scale (NRS), QuickDASH, Canadian Occupational Performance Measure (COPM), and proprioception via joint position sense (JPS).

RESULTS

Fifty-two females participated in the study. Both the experimental and control group made both clinically and statistically significant changes in the mean VAS and COPM scores over time. Only the experimental group achieved a statistically and clinically significant change in JPS error score over time.

DISCUSSION

Experimental group achieved a statistically significant change in JPS over time in concordance with previous investigations. Changes in pain scores differed from prior investigations and the between-group comparison was not statistically significant. Changes in the Quick DASH was similar to previous findings.

CONCLUSION

Proprioceptive training in addition to a traditional rehabilitation program decreased error scores on the joint position sense test.

Dynamic stabilization of the painful thumb: A historical and evidence-informed synthesis

STUDY DESIGN

Expert opinion INTRODUCTION: Thumb carpometacarpal joint (CMC) osteoarthritis is a common condition seen in the hand therapy clinic. Prevalence is generally higher in females, and the percentage rises for post-menopausal females. Patients typically present with pain and functional difficulties. Conservative management is recommended before a surgical consult. Evidence is mounting that a dynamic stability modeled approach has a significant effect on pain and improving function.

PURPOSE

The purpose of this paper is two-fold: first, to present the history and development of a dynamic stabilization model for treatment of the patient with thumb CMC osteoarthritis (OA), and second, to provide expert clinical commentary and recommendations for the treatment of thumb CMC OA in light of the best available evidence.

METHODS

Expert clinical commentary is based on an extensive review of relevant literature.

RESULTS

The current literature and expert opinion supports an evidence-informed multimodal intervention: modalities, pain relief techniques, manual release, joint mobilizations as deemed necessary, neuromuscular re-education through proprioceptive exercises, and education in joint protection principles.

CONCLUSION

A rationale for a dynamic stabilization approach is presented. The unique anatomy of the thumb deserves finely tuned care based on high quality research. To advance our knowledge and clinical skills we must not become stagnant, but continue to generate high level evidence. The standard for future thumb CMC OA studies should be well-defined intervention parameters, consistent documentation, and the use of appropriate patient-rated outcome measures.

Indications for Ligament Reconstruction and Suspensionplasty in Carpometacarpal Arthroplasty

The trapeziometacarpal joint is the site that most commonly develops arthritis in the hand. Although optimal treatment requires careful consideration of history, physical examination, radiographs, and functional goals, many patients ultimately undergo surgical intervention. Several described techniques and approaches are highlighted in this article, especially pertaining to carpometacarpal arthroplasty with ligament reconstruction and tendon interposition. The rationale, benefit, and evidence for each approach are discussed and the author's preferred technique is described.

Anatomy and Biomechanics of the Thumb Carpometacarpal Joint

This review discusses the anatomy and biomechanics of the thumb carpometacarpal (CMC) joint. This articulation between the trapezium and first metacarpal is integral for opposition and other complex movements necessary for pinch and grasp maneuvers. Fortunately, this joint is well equipped to handle the extreme forces imposed by these movements, as it is stabilized by an elaborate arrangement of ligaments and muscles. Without this stability, thumb subluxation would occur with loading during pinch and grasp, and human prehension would be impossible. Understanding the interactions occurring within this joint is essential for adequately treating pathology arising in this crucial joint.

Alteration of Ligamento-Muscular Reflex Patterns After Cutaneous and Periarticular Desensitization of the Basal Thumb Joint: An Electromyographic Study

PURPOSE

Stimulation of the dorsoradial ligament (DRL) of the first carpometacarpal joint (CMC-1) has shown a ligamento-muscular reflex pathway between the DRL and CMC-1 stabilizing muscles in healthy volunteers. However, it remains unclear how this ligamento-muscular reflex pattern is altered after anesthetizing sensory skin receptors and administering a further periarticular block around the CMC-1 joint, which may influence the dynamic aspects of joint stability.

METHODS

Ligamento-muscular reflexes were obtained from the extensor pollicis longus, abductor pollicis longus, abductor pollicis brevis, and the first dorsal interosseous muscles in 10 healthy participants after establishing superficial anesthesia of the skin around the CMC-1. The DRL was stimulated with a fine wire electrode while EMG activities were recorded during isometric tip, key, and palmar pinch. The measurements were repeated after an additional periarticular CMC-1 block using 5 ml of 1% lidocaine. Average EMG values were analyzed to compare the prestimulus and poststimulus activity.

RESULTS

Statistically significant changes in poststimulus EMG activity were observed in all 4 muscles and all 3 tested thumb positions. A markedly reduced activity in all 4 muscles was observed in the palmar position, followed by the tip and key pinch positions. Almost no reactions were observed in the first 20 ms poststimulus for all muscles in all positions.

CONCLUSIONS

Superficial skin anesthesia and an additional periarticular CMC-1 block anesthesia resulted in a reduced ligamento-muscular reflex pattern in all 4 muscles.

CLINICAL RELEVANCE

Ligamento-muscular reflexes play an important role in dynamic CMC-1 joint stability. The elimination of early reactions, those considered joint-protective reflexes, is a potential risk factor for developing osteoarthritis or injury because it results in an inability to adequately protect and stabilize the joint in sudden movements.

Thumb Carpometacarpal Instability

The basal joint complex of the thumb provides the framework necessary for function of the human hand. Although its unique saddle articulation allows for a wide range of motion necessary for routine function of the hand, it is rendered inherently unstable because of poor bony congruency and reliance on its capsuloligamentous support. Painful instability of this joint can stem from several causes including traumatic dislocation, various hypermobility conditions, and chronic overuse and microtrauma. A thorough history and examination as well adequate imaging is necessary for proper evaluation of instability. Treatment options range from nonoperative modalities to surgery, which entails closed, percutaneous, or open reduction with numerous ligament repair and reconstruction techniques. Arthroscopy can also serve to be a useful adjunct for assessment of the joint and stabilization of the critical capsuloligamentous structures. This review outlines the critical osseous and soft-tissue anatomy surrounding the thumb carpometacarpal joint, the key points in evaluating patients presenting with acute traumatic and chronic thumb carpometacarpal instability without fracture or arthritis, and reviews both nonoperative and operative treatments of this injury.

Joint position sense impairments in older adults with carpometacarpal osteoarthritis: A descriptive comparative study

STUDY DESIGN

This study has a descriptive-comparative, cross-sectional design.

INTRODUCTION

Sensorimotor (SM) impairments have been observed after common wrist and hand injuries such as distal radius fractures. However, there is a lack of research regarding SM impairments in patients with carpometacarpal (CMC) osteoarthritis (OA).

PURPOSE OF THE STUDY

This study sought to quantify proprioception deficits in older adults with CMC OA as compared with healthy adults using the joint position sense (JPS) test.

METHODS

The active JPS test was used to measure proprioception function in 29 thumbs with CMC OA and their 29 matched-control healthy counterparts. For comparison, participants with unilateral CMC OA were matched against themselves, whereas those with lateral CMC OA were age matched with a healthy participant. Data analysis was performed to compute the mean error of JPS; an unpaired t test was used to compare the mean error of the non-CMC OA group with the healthy control group.

RESULTS

The mean positional error measured from subjects with CMC OA was 9.53° compared with 1.32° for the age-matched healthy subjects. The effect size for the difference in means was D = 1.96.

CONCLUSIONS

Thumb SM impairments were found to be greater in subjects with CMC OA than in their healthy counterparts when using the JPS test to assess proprioception.

Anatomy and biomechanics of healthy and arthritic trapeziometacarpal joints

Understanding the biomechanics of the trapeziometacarpal (TMC) or first carpometacarpal (CMC1) joint, the pathophysiology of basal thumb arthritis, the design and performance of surgical procedures require a solid anatomical basis. This review of literature summarizes the most recent data on the descriptive, functional, and comparative anatomy of healthy and arthritic TMC joints.

Is Thumb Proprioception Decreased in Patients With Trapeziometacarpal Joint Osteoarthritis?

Proprioception is thought to be essential for normal joint homeostasis, and its decreased function has been associated with an increased risk of joint diseases. However, only a few studies have been performed on the association between proprioceptive function in the trapeziometacarpal joint (TMCJ) and osteoarthritis. The purpose of this study was to compare TMCJ proprioceptive function in elderly women with radiographic TMCJ osteoarthritis relative to age-matched control women without osteoarthritis. We enrolled 19 women (mean age, 66 years) with symptomatic, radiographic Eaton and Littler grade 2, 3, and 4 TMCJ osteoarthritis and 19 age-matched control women without osteoarthritis. We evaluated thumb proprioception by using a joint-position reproduction test and compared the reposition error (RE) between the groups. We carried out a multivariate analysis for factors potentially associated with increased RE, such as age, body mass index, hand dominance, the presence of diabetes, pain level, and the presence of osteoarthritis. Also, a logistic regression analysis was performed for factors associated with the occurrence of TMCJ osteoarthritis. Patients with TMCJ osteoarthritis had greater RE than did the control patients in the joint-position reproduction test at 20°, 30°, and 40° of thumb palmar abduction. The multivariate analysis indicated that increased RE was associated with the presence of osteoarthritis, but not with the other factors assessed. The occurrence of TMCJ osteoarthritis was associated with increased RE at 20°, 30°, and 40° of thumb palmar abduction. This study showed that decreased proprioceptive function was associated with the presence of osteoarthritis in the TMCJ, although the causality remains unknown. Further studies on the role of proprioception in the pathogenesis of TMCJ osteoarthritis and the potential role of its training for disease prevention or treatment are required.

Addition-Subtraction Osteotomy With Ligamentoplasty for Symptomatic Trapezial Dysplasia With Metacarpal Instability: A 10-Year Follow-Up

PURPOSE

Symptomatic trapezial dysplasia with metacarpal instability in a nonarthritic joint can lead to a disabling condition characterized by decreased pain, mobility, and strength. Bony correction may be required in dysplastic joints, because soft tissue correction might be insufficient to stabilize the trapeziometacarpal (TMC) joint. We combined 2 techniques described previously, an abduction-extension osteotomy of the first metacarpal and an opening wedge osteotomy of the trapezium, including a ligament reconstruction (hemi-flexor carpi radialis). The aim of this study was to investigate the long-term results of this technique.

METHODS

In this single-center, retrospective cohort study, we included patients treated surgically for primary instability of the TMC joint with trapezial dysplasia between 2003 and 2007. We measured pain (visual analog scale), mobility (opposition and retropulsion), patient-reported disability (Quick-Disabilities of the Arm, Shoulder, and Hand), and radiographic evaluation (Devers' angle) 10 years after surgery. Results were compared with preoperative data.

RESULTS

We reviewed 17 thumbs retrospectively (mean follow-up, 12 years). One patient was converted to a TMC prosthesis. Key pinch improved significantly from 5.2 kg (±2.4 kg) at baseline to 6.3 kg (±2.1 kg) at 10-year follow-up. Quick-Disabilities of the Arm, Shoulder, and Hand score and Devers' angle were significantly better after 10 years compared with preoperative data. There was a mean visual analog scale score of 0.5 (±1.4) at rest and 2.3 (±2.6) during activities. Ten years after surgery, 5 patients had a stable Eaton score of 1. Four patients had progression to stage 2, and 5 to stage 3.

CONCLUSIONS

Addition-subtraction osteotomy with ligamentoplasty has a positive long-term effect on symptomatic trapezial dysplasia with TMC joint instability. Although this operation did not protect the TMC joint from further wear, pain was acceptable for most patients.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Topography of sensory receptors within the human glenohumeral joint capsule

BACKGROUND AND HYPOTHESES

Sensory receptors in the joint capsule are critical for maintaining joint stability. However, the distribution of sensory receptors in the glenohumeral joint of the shoulder, including mechanoreceptors and free nerve endings, has not been described yet. This study aimed to describe the distributions of different sensory receptor subtypes in the glenohumeral joint capsule. Our hypotheses were as follows: (1) Sensory receptor subtypes would differ in density but follow a similar distribution pattern, and (2) the anterior capsule would have the highest density of sensory receptors.

METHODS

Six glenohumeral joint capsules were harvested from the glenoid to the humeral attachment. The capsule was divided into 4 regions of interest (anterior, posterior, superior, and inferior) and analyzed using modified gold chloride stain. Sensory receptors as well as free nerve endings were identified and counted under a light microscope from sections of each region of interest. The density of each sensory receptor subtype was calculated relative to capsule volume.

RESULTS

Sensory receptors were distributed in the glenohumeral joint capsule with free nerve endings. The anterior capsule exhibited the highest median density of all 4 sensory receptors examined, followed by the superior, inferior, and posterior capsules. The median densities of these sensory receptor subtypes also significantly differed (P = .007), with type I (Ruffini corpuscles) receptors having the highest density (2.97 U/cm³), followed by type IV (free nerve endings, 2.25 U/cm³), type II (Pacinian corpuscles, 1.40 U/cm³), and type III (Golgi corpuscles, 0.24 U/cm³) receptors.

CONCLUSION

Sensory receptor subtypes are differentially expressed in the glenohumeral joint capsule, primarily type I and IV sensory receptors. The expression of sensory receptors was dominant in the anterior capsule, stressing the important role of proprioception feedback for joint stability. The surgical procedure for shoulder instability should consider the topography of sensory receptors to preserve or restore the proprioception of the shoulder joint.

Therapy Considerations for Getting Athletes to Return to Play

During the protective phase of treatment, therapy for hand and wrist injuries in athletes is similar to the plan of care provided to all patients. The nuances in the care provided to athletes become apparent during the transition to the postprotective phase of rehabilitation when the focus has shifted to return to play. Therapy following a sports injury should address the individual needs of the athletes in their everyday lives as well as the specificity of their training and sports-specific activities. The factors that influence return to play are discussed.

Immunofluorescence analysis of sensory nerve endings in the interosseous membrane of the forearm

The human interosseous membrane (IOM) is a fundamental stabilizer during forearm rotation. To investigate the dynamic aspects of forearm stability, we analyzed sensory nerve endings in the IOM. The distal oblique bundle (DOB), the distal accessory band (DAB), the central band (CB), the proximal accessory band (PAB), the dorsal oblique accessory cord (DOAC) and the proximal oblique cord (POC) were dissected from 11 human cadaver forearms. Sensory nerve endings were analyzed at two levels per specimen as total cell amount/mm² after immunofluorescence staining with low-affinity neurotrophin receptor p75, protein gene product 9.5, S-100 protein and 4',6-diamidino-2-phenylindole on an Apotome microscope, according to Freeman and Wyke's classification. Sensory nerve endings were significantly more commonly found to be equally distributed throughout the structures, rather than being epifascicular, interstitial, or close to the insertion into bone (P ≤ 0.001, respectively). Free nerve endings were the predominant mechanoreceptor in all six structures, with highest density in the DOB, followed by the POC (P ≤ 0.0001, respectively). The DOB had the highest density of Pacini corpuscles. The DOAC and CB had the lowest amounts of sensory innervation. The high density of sensory corpuscles in the DOB, PAB and POC indicate that proprioceptive control of the compressive and directional muscular forces acting on the distal and proximal radioulnar joints is monitored by the DOB, PAB and POC, respectively, due to their closed proximity to both joints, whereas the central parts of the IOM act as structures of passive restraint.

Suture Suspension Arthroplasty With Trapeziectomy for Thumb Carpometacarpal Arthritis Using a Wide-awake Approach

Despite the introduction of various techniques for ligament reconstruction in the treatment of thumb carpometacarpal (CMC) arthritis, complications, including proximal migration, dorsal subluxation of the first metacarpal base, hyperextension of the thumb metacarpophalangeal joint, and impingement between the first and second metacarpal bases, have been reported. Even suture button suspensionplasty with Arthrex Mini TightRope may be unable to correct the adduction contracture deformity and does not effectively tether the trapeziometacarpal toward the base of the index metacarpal, thus potentially leaving patients with persistent decreased first web space angle, proximal migration, and collapse deformity. Hence, suture suspension arthroplasty with abductor pollicis longus (APL)-flexor carpi radialis (FCR) tendon suture after trapeziectomy, a simpler technique, was applied. This simple surgical reconstruction abducts the first metacarpal bone. Abduction of the CMC joint improves metacarpophalangeal joint hyperextension. However, strong tension of the APL-FCR causes abduction contracture of the first CMC joint and difficulty of pinch motion of the thumb to the other fingers. Therefore, we have modified the arthroplasty with a wide-awake approach. The procedure is performed with the patient fully awake under local anesthesia, without a tourniquet to allow the patient to actively move and pinch the thumb, which allows the surgeon to confirm the tension of the APL-FCR suture. A fiber wire is connected to the APL-FCR with proper tension. The patient and surgeon can ensure pinch motion and thumb opposition with satisfaction during surgery.

Osteophyte growth in early thumb carpometacarpal osteoarthritis

OBJECTIVE

Osteophyte formation is a critical part of the degeneration of a joint with osteoarthritis (OA). While often qualitatively described, few studies have succeeded in quantifying osteophyte growth over time. Using computed tomography (CT) image data from a longitudinal, observational study of thumb carpometacarpal (CMC) OA, our aim was to quantify osteophyte growth volume and location over a three-year period in men and women.

METHOD

Ninety patients with early thumb OA were recruited and assessed at baseline, 1.5 years, and 3 years with CT imaging. Osteophyte volume and location on the trapezium and first metacarpal were determined using a library of 46 healthy subjects as a nonarthritic reference database.

RESULTS

There was a significant increase in osteophyte volume for women and men over the three-year follow-up in the trapezium (86.8 mm³-120.5 mm³ and 165.1 mm³-235.3 mm³, means respectively) and in the proximal metacarpal (63 mm³-80.4 mm³, and 115.8 mm³-161.7 mm³, respectively). The location of osteophyte initiation and growth was consistent across subjects and was located in non-opposing regions on the trapezium and first metacarpal. Osteophyte growth occurred about the radial and ulnar margins of the trapezial facet, while on the proximal metacarpal, growth occurred principally about the volar and dorsal margins of the facet.

CONCLUSION

Osteophyte growth occurred in early thumb osteoarthritis over three years. Growth was localized in specific, non-opposing regions on the trapezium and metacarpal, raising intriguing questions about the triggers for their formation, whether the mechanisms are mechanical, biological or a combination of both.

Neuroanatomical distribution of sensory receptors in the human elbow joint capsule

BACKGROUND

The topographic arrangement of sensory receptors in the human elbow joint capsule is pertinent to their role in the transmission of neural signals. The signals from stimuli in the joint are concisely delivered via afferent pathways to allow recognition of pain and proprioception. Sensory receptors in the elbow joint include mechanoreceptors and free nerve endings acting as nociceptors, although the distribution of each of the structures has not been determined, despite their importance for the integrity of the joint. We therefore aimed to investigate the neuroanatomical distribution and densities of mechanoreceptors and free nerve endings in the capsule of the elbow, at the same time as considering surgical approaches that would result in the minimum insult to them.

METHODS

Four elbow joint capsules were harvested from fresh cadavers. The specimens were carefully separated from adjacent osteoligamentous attachments and the capsular complex was stained with a modified gold chloride method. Evaluations of free nerve endings, and Golgi, Ruffini and Pacinian corpuscles were performed under an inverted light microscope. The number and density of each structure were recorded.

RESULTS

Ruffini corpuscles observed to be the dominant mechanoreceptor type. No Golgi corpuscle was observed. Free nerve endings were found at the highest density at posterodistal sites, whereas mechanoreceptors were most frequent at bony attachment sites.

CONCLUSIONS

A consistent distribution pattern of articular sensory receptors was observed, which allows further understanding of elbow pathology. An awareness of the neuroanatomical distribution of sensory receptors in the elbow joint capsule may allow their preservation during surgical procedures for elbow joint pathology.

Ligamento-Muscular Reflex Patterns Following Stimulation of a Thumb Carpometacarpal Ligament: An Electromyographic Study

PURPOSE

The dorsoradial ligament (DRL) is essential for stability of the first carpometacarpal joint (CMC1) and is innervated with nerve endings and mechanoreceptors known to contribute to joint proprioception. The influence of these nerve endings on the neuromuscular stability of CMC1 is not yet known. This study investigated whether a ligamento-muscular reflex pathway is present between the DRL and CMC1 muscles.

METHODS

Ten healthy subjects (5 women and 5 men, mean age 28 years; range, 24-37 years) were included. Four primary CMC1 stabilizing muscles were investigated: the extensor pollicis longus, abductor pollicis longus (APL), abductor pollicis brevis, and first dorsal interosseous. Needle electrodes were inserted into each muscle and a fine-wire electrode was inserted into the DRL. The DRL was stimulated at 200 MHz while EMG activities in the muscles were recorded during isometric tip, key, and palmar pinch. Average EMG values were analyzed to compare prestimulus (t₁) with post-stimulus (t₂) activity.

RESULTS

Poststimulus changes were observed in all 4 muscles and 3 positions tested. During tip pinch we observed mass inhibition with a decrease in all muscle amplitudes. In key pinch we observed a rapid co-contraction response. Rapid inhibitory response of antagonistic musculature was observed during palmar pinch. The APL was the only muscle to react within 20 ms after stimulation.

CONCLUSIONS

We identified CMC1 ligamento-muscular reflexes. The mass inhibition of activity observed during tip pinch indicated a protective ligamento-muscular relation that affects all 4 muscles. The co-contractions observed promote joint stability. The fast response in the APL, coupled with its neuroanatomical proximity to the DRL, indicate a particular role in CMC1 proprioception.

CLINICAL RELEVANCE

Proper ligamentous support and retained innervation is likely important for adequate joint function; their innate functions ought to be considered when planning surgical or orthotic treatments.

Selective Thumb Carpometacarpal Joint Denervation for Painful Arthritis: Clinical Outcomes and Cadaveric Study

PURPOSE

To determine the innervation pattern to the thumb carpometacarpal (CMC) joint and assess the safety and efficacy of selective joint denervation for the treatment of pain and impairment associated with thumb CMC arthritis.

METHODS

Cadaveric dissections were performed in 10 fresh upper extremities to better define the innervation patterns to the CMC joint and guide the surgical approach for CMC joint denervation. Histologic confirmation of candidate nerves was performed with hematoxylin and eosin staining. Results from a series of 12 patients with symptomatic thumb CMC arthritis who underwent selective denervation were retrospectively evaluated to determine the safety and efficacy of this treatment approach. Differences in preoperative and postoperative measurements of grip and key-pinch strength as well as subjective reporting of symptoms were compared.

RESULTS

Nerve branches to the thumb CMC joint were found to arise from the lateral antebrachial cutaneous nerve (10 of 10 specimens), the palmar cutaneous branch of the median nerve (7 of 10 specimens), and the radial sensory nerve (4 of 10 specimens). With an average follow-up time of 15 months, 11 of 12 patients (92%) reported complete or near-complete relief of pain. Average improvements in grip and lateral key-pinch strength were 4.1 ± 3.0 kg (18% ± 12% from baseline) and 1.7 ± 0.5 kg (37% ± 11% from baseline), respectively. One patient experienced the onset of new pain consistent with a neuroma that resolved with steroid injection. All patients were released to light activity at 1 week after surgery, and all activity restrictions were lifted by 6 weeks after surgery.

CONCLUSIONS

Selective denervation of the CMC joint is an effective approach to treat pain and alleviate impairment associated with CMC arthritis. The procedure is well tolerated, with faster recovery as compared with trapeziectomy. Branches arising from the lateral antebrachial cutaneous nerve, palmar cutaneous branch of the median nerve, and radial sensory nerve can be identified and resected with a single-incision Wagner approach.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

Exercise Therapy in Addition to an Orthosis Reduces Pain More Than an Orthosis Alone in Patients With Thumb Base Osteoarthritis: A Propensity Score Matching Study

OBJECTIVE

To compare the effect of exercises and orthotics with orthotics alone on pain and hand function in patients with first carpometacarpal joint (CMC-1) osteoarthritis (OA) and to predict outcomes on pain and hand function of exercises and orthotics.

DESIGN

Prospective cohort study with propensity score matching.

SETTING

Data collection took place in 13 outpatient clinics for hand surgery and hand therapy in The Netherlands.

PARTICIPANTS

A consecutive, population-based sample of patients with CMC-1 OA (N=173) was included in this study, of which 84 were matched on baseline demographics and baseline primary outcomes.

INTERVENTIONS

Exercises and orthotics versus orthotics alone.

MAIN OUTCOME MEASURES

Primary outcomes included pain and hand function at 3 months, measured using visual analog scale (VAS, 0-100) and the Michigan Hand Outcomes Questionnaire (MHQ, 0-100).

RESULTS

A larger decrease in VAS pain at rest (11.1 points difference; 95% confidence interval, 1.9-20.3; P=.002) and during physical load (22.7 points difference; 95% confidence interval, 13.6-31.0; P<.001) was found in the exercise + orthotic group compared to the orthotic group. In addition, larger improvement was found for the MHQ subscales pain, work performance, aesthetics, and satisfaction in the exercise + orthotic group. No differences were found on other outcomes. Baseline scores of metacarpophalangeal flexion, presence of scaphotrapeziotrapezoid OA, VAS pain at rest, heavy physical labor, and MHQ total predicted primary outcomes for the total exercise + orthotic group (N=131).

CONCLUSIONS

Non-surgical treatment of patients with CMC-1 OA should include exercises, since there is a relatively large treatment effect compared to using an orthosis alone. Future research should study exercises and predictors in a more standardized setting to confirm this finding.

Mechanoreceptors distribution in the human medial collateral ligament of the elbow

BACKGROUND

The human elbow maintains its stability mainly through its bony structure. Stability is enhanced by ligamentous structures. To allow the ligamento-muscular reflex, which protects against strain and stress, mechanoreceptors are embedded in the ligament. This report describes the existence and the distribution of the elbow medial collateral ligaments (MCLs) mechanoreceptors.

HYPOTHESIS

The bony attachment site has the highest density of mechanoreceptors, and the anterior part has the highest density of mechanoreceptors.

MATERIALS AND METHODS

Eight MCLs of elbow from fresh frozen cadavers were used. The MCLs were harvested deep to the periosteum from the medial epicondyle to the ulna. The fan-shaped ligaments were divided into six regions of interest (ROI) and stained with modified gold chloride stain. Specimens were evaluated under a light microscope. Golgi, Ruffini, and Pacinian corpuscles were found in every specimen. The number and the distribution of each mechanoreceptor in each ROI were recorded. The density of each mechanoreceptor was calculated in regards to its volume.

RESULTS

Golgi, Ruffini, and Pacinian corpuscles were seen in the ligament with small nerve fibers. Ruffini corpuscles had the highest median density of all three corpuscles. The median corpuscle density was higher in the anterior than in the posterior part and higher in the bony attachment than in the mid-substance site except for Golgi corpuscle.

CONCLUSION

The three typical types of mechanoreceptors were identified in human MCL with the anterior part and bony attachment as the dominant distribution site.

LEVEL OF EVIDENCE

Basic Science Study.

The Teleology of the Thumb: On Purpose and Design

The Andrew J. Weiland Medal is presented by the American Society for Surgery of the Hand to a midcareer researcher dedicated to advancing patient care in the field of hand surgery. The Weiland Medal for 2017 was presented to the author at the annual meeting of the American Society for Surgery of the Hand. The purpose of this article is to present current evidence on how biomechanics and morphology influence the pathophysiology of thumb carpometacarpal joint osteoarthritis.

Scapholunate interosseous ligament dysfunction as a source of elbow pain syndromes: Possible mechanisms and implications for hand surgeons and therapists

Elbow pain syndromes are common upper extremity musculoskeletal disorders, and they are usually associated with repetitive occupational exposure. Ligaments are often one of the sources of musculoskeletal disorders because of their mechanical and neurological properties. The wrist ligaments are some of the ligaments most vulnerable to occupational exposure. Since most occupational tasks require wrist extension for handling tools and loading, the scapholunate interosseous ligament (SLIL) bears greater strain during loading, which results in creep deformation and hysteresis. Ligamentous creep may result in diminished ability to detect signal changes during joint movements, which impairs neuromuscular control established by ligamentomuscular reflex arcs elicited from mechanoreceptors in the ligaments. Changes in muscle activation patterns of forearm muscles due to diminished ligamentomuscular reflexes may initiate a positive feedback loop, leading to musculoskeletal pain syndromes. The relationship between elbow pain syndromes and SLIL injury will be presented through two hypotheses and relevant pain mechanisms: 1. Repetitive tasks may cause creep deformation of the SLIL, which then impairs ligamentomuscular reflexes, leading to elbow pain disorders. 2. Lateral epicondylalgia may increase the risk of SLIL injury through the compensation of the lower extensor carpi radialis muscle activity by higher extensor carpi ulnaris muscle activity, which may alter carpal kinematics, leading to SLIL degeneration over time. The differential diagnosis is usually complicated in musculoskeletal pain disorders. The failure of treatment methods is one of the issues of concern for many researchers. A key element in developing treatment strategies is to understand the source of the disorder and the nature of the injury. We proposed that the differential diagnosis include SLIL injuries when describing elbow pain syndromes, particularly, lateral epicondylalgia.

Conservative treatment of Myofascial Trigger Points and joint mobilization for management in patients with thumb carpometacarpal osteoarthritis

In an attempt to decrease pain and increase function in patients with CMC OA, these authors have described the combination of two techniques that can be performed to treat this common problem. Before applying the techniques, each therapist must determine if the application of the technique falls within their scope of practice. - KristinValdes, OTD, OT, CHT, Practice Forum Editor.

Trapeziometacarpal Ligaments Biomechanical Study: Implications in Arthroscopy

Purpose In the presence of early osteoarthritis, changes to the trapeziometacarpal joint (TMJ) often result in pain and is associated with joint instability and a tendency of dorsoradial subluxation. In these instances, arthroscopy may be indicated to: (1) assess the extent of cartilage disease and the laxity of ligaments and to (2) treat TMJ instability. The purpose of our study was to biomechanically analyze which ligaments are the primary stabilizers of the TMJ. Methods Overall, 11 fresh-frozen human cadaver specimens were dissected and attached to a testing device with the thumb positioned in neutral abduction, neutral flexion, and neutral opposition. The four extrinsic and five intrinsic muscle tendons acting on the TMJ were simultaneously loaded with weights proportional to their physiological cross-sectional area. The dorsal, volar, and ulnar groups of ligaments were dissected. A motion-tracking device, FasTrak (Polhemus Inc., Colchester, VT), was used to study the spatial position of the base of the first metacarpal bone (MC1), before and after random sectioning of each of the ligaments. Statistical analysis of the MC1 translation along the transverse XY plane was performed using one-way analysis of variance and a paired t-test, with a significance level of p < 0.05. Results After isolated sectioning of the volar or the ulnar ligaments, the MC1 moved dorsoradially with an average of 0.150 mm (standard deviation [SD]: 0.072) and 0.064 mm (SD: 0.301), respectively. By contrast, the destabilization of the MC1 after sectioning of the dorsal ligaments was substantially larger (0.523 mm; SD: 0.0512; p = 0.004). Conclusion Sectioning of the dorsal ligament group resulted in the greatest dorsoradial translation of the MC1. Consequently, the dorsal ligaments may be regarded as the primary TMJ stabilizers. Clinical Relevance This study suggests that stabilizing arthroscopic shrinkage of the TMJ should be targeted toward the dorsal TMJ ligaments.

Mobilization with movement and elastic tape application for the conservative management of carpometacarpal joint osteoarthritis

Carpometacarpal osteoarthritis can limit a person's ability to engage in desired activities. Many therapists utilize conservative approaches to assist these patients. These authors describe utilizing a combination of mobilization with movement and the use of elastic tape for patients with this arthritis. - Victoria Priganc, PhD, OTR, CHT, CLT, Practice Forum Editor.

Altered Innervation Pattern in Ligaments of Patients with Basal Thumb Arthritis

Purpose The population of mechanoreceptors in patients with osteoarthritis (OA) lacks detailed characterization. In this study, we examined the distribution and type of mechanoreceptors of two principal ligaments in surgical subjects with OA of the first carpometacarpal joint (CMC1). Methods We harvested two ligaments from the CMC1 of eleven subjects undergoing complete trapeziectomy and suspension arthroplasty: the anterior oblique (AOL) and dorsal radial ligament (DRL). Ligaments were divided into proximal and distal portions, paraffin-sectioned, and analyzed using immunoflourescent triple staining microscopy. We performed statistical analyses using the Wilcoxon Rank Sum test and ANOVA with post-hoc Bonferroni and Tamhane adjustments. Results The most prevalent nerve endings in the AOL and DRL of subjects with OA were unclassifiable mechanoreceptors, which do not currently fit into a defined morphological scheme. These were found in 11/11 (100%) DRLs and 7/11 (63.6%) AOLs. No significant difference existed with respect to location within the ligament (proximal versus distal) of mechanoreceptors in OA subjects. Conclusion The distribution and type of mechanoreceptors in cadavers with no to mild OA differ from those in surgical patients with OA. Where Ruffini endings predominate in cadavers with no to mild OA, unclassifiable corpuscles predominate in surgical patients with OA. These findings suggest an alteration of the mechanoreceptor population and distribution that accompanies the development of OA. Clinical Relevance Identification of a unique type and distribution of mechanoreceptors in the CMC1 of symptomatic subjects provides preliminary evidence of altered proprioception in OA.

Evaluation of Radiographic Instability of the Trapeziometacarpal Joint in Women With Carpal Tunnel Syndrome

PURPOSE

To determine whether median nerve dysfunction measured by electrophysiologic studies in carpal tunnel syndrome (CTS) is associated with thumb trapeziometacarpal (TMC) joint instability.

METHODS

We evaluated 71 women with CTS and 31 asymptomatic control women. Patients with generalized laxity or TMC joint osteoarthritis were excluded. We classified the electrophysiologic severity of CTS based on nerve conduction time and amplitude and assessed radiographic instability of the TMC joint based on TMC joint stress radiographs. We compared subluxation ratio between patients with CTS and controls and performed correlation analysis of the relationship between the electrophysiologic grade and subluxation ratio.

RESULTS

Thirty-one patients were categorized into the mild CTS subgroup and 41 into the severe CTS subgroup. There was no significant difference in subluxation ratio between the control group and CTS patients or between the control group and CTS subgroup patients. Furthermore, there was no significant correlation between electrophysiologic grade and subluxation ratio.

CONCLUSIONS

This study demonstrated that patients with CTS did not have greater radiographic TMC joint instability compared with controls, and suggests that TMC joint stability is not affected by impaired median nerve function. Further studies could investigate how to better evaluate proprioceptive function of TMC joint and whether other nerves have effects on TMC joint motor/proprioceptive function, to elucidate the relationship between neuromuscular control of the TMC joint, its stability, and its progression to osteoarthritis.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

Ulnar digits contribution to grip strength in patients with thumb carpometacarpal osteoarthritis is less than in normal controls

BACKGROUND

Grip testing is commonly used as an objective measure of strength in the hand and upper extremity and is frequently used clinically as a proxy measure of function. Increasing knowledge of hand biomechanics, muscle strength, and prehension patterns can provide us with a better understanding of the functional capabilities of the hand. The objectives of this study were to determine the contribution of ulnar digits to overall grip strength in individuals with thumb carpometacarpal (CMC) osteoarthritis (OA).

METHODS

Thirty-seven subjects participated in the study. This group consisted of 19 patients with CMC OA (aged 60-88 years) and 18 healthy subjects (60-88 years). Three hand configurations were used by the subjects during grip testing: use of the entire hand (index, middle, ring, and little fingers) (IMRL); use of the index, middle, and ring fingers (IMR); and use of only the index and middle fingers (IM).

RESULTS

Grip strength findings for the two groups found that compared to their healthy counterparts, CMC OA patients had, on average, a strength deficiency of 45.6, 35.5, and 28.8 % in IMRL, IMR, and IM, respectively. The small finger contribution to grip is 14.3 % and the ring and small finger contribute 34 % in subjects with CMC OA.

DISCUSSION

Grip strength decreases as the number of digits contributing decreased in both groups. The ulnar digits contribution to grip strength is greater than one third of total grip strength in subjects with CMC OA. Individuals with CMC OA demonstrate significantly decreased grip strength when compared to their healthy counterparts.

Using smartphone applications as hand therapy interventions

In the hand therapy clinic, smartphones can be used as an educational resource, to view a photo or video of a home exercise program, or as a method of electronically documenting progress related to healing from an injury. Smartphone applications may also serve as appropriate therapy interventions to address deficits often presenting with common hand injuries. For individuals with trapeziometacarpal arthrosis, gaming can encourage radial abduction range of motion and neuromuscular control required for joint stability. People with distal radius fractures may benefit from smartphone applications for range of motion and proprioceptive training. These treatments may assist with addressing client-centered goals and be motivating in the current technology driven times.

In vivo recruitment patterns in the anterior oblique and dorsoradial ligaments of the first carpometacarpal joint

The anterior oblique ligament (AOL) and the dorsoradial ligament (DRL) are both regarded as mechanical stabilizers of the thumb carpometacarpal (CMC) joint, which in older women is often affected by osteoarthritis. Inferences on the potential relationship of these ligaments to joint pathomechanics are based on clinical experience and studies of cadaveric tissue, but their functions has been studied sparsely in vivo. The purpose of this study was to gain insight into the functions of the AOL and DRL using in vivo joint kinematics data. The thumbs of 44 healthy subjects were imaged with a clinical computed tomography scanner in functional-task and thumb range-of-motion positions. The origins and insertion sites of the AOL and the DRL were identified on the three-dimensional bone models and each ligament was modeled as a set of three fibers whose lengths were the minimum distances between insertion sites. Ligament recruitment, which represented ligament length as a percentage of the maximum length across the scanned positions, was computed for each position and related to joint posture. Mean AOL recruitment was lower than 91% across the CMC range of motion, whereas mean DRL recruitment was generally higher than 91% in abduction and flexion. Under the assumption that ligaments do not strain by more than 10% physiologically, our findings of mean ligament recruitments across the CMC range of motion indicate that the AOL is likely slack during most physiological positions, whereas the DRL may be taut and therefore support the joint in positions of CMC joint abduction and flexion.

Thumb ligament injuries

Thumb ligament injuries are common, particularly those involving the metacarpophalangeal joint. Our understanding and treatment of these injuries continues to evolve. This article provides a comprehensive review of recent literature with updates pertaining to the anatomy, function, diagnosis, and treatment of thumb ligament injuries.

The 2014 ABJS Nicolas Andry Award: The puzzle of the thumb: mobility, stability, and demands in opposition

BACKGROUND

The paradoxical demands of stability and mobility reflect the purpose and function of the human thumb. Its functional importance is underscored when a thumb is congenitally absent, injured, or afflicted with degenerative arthritis. Prevailing literature and teaching implicate the unique shape of the thumb carpometacarpal (CMC) joint, as well as its ligament support, applied forces, and repetitive motion, as culprits causing osteoarthritis (OA). Sex, ethnicity, and occupation may predispose individuals to OA.

QUESTIONS/PURPOSES

What evidence links ligament structure, forces, and motion to progressive CMC disease? Specifically: (1) Do unique attributes of the bony and ligamentous anatomy contribute to OA? (2) Can discrete joint load patterns be established that contribute to OA? And (3) can thumb motion that characterizes OA be measured at the fine and gross level?

METHODS

We addressed the morphology, load, and movement of the human thumb, emphasizing the CMC joint in normal and arthritic states. We present comparative anatomy, gross dissections, microscopic analysis, multimodal imaging, and live-subject kinematic studies to support or challenge the current understanding of the thumb CMC joint and its predisposition to disease.

RESULTS

The current evidence suggests structural differences and loading characteristics predispose the thumb CMC to joint degeneration, especially related to volar or central wear. The patterns of degeneration, however, are not consistently identified, suggesting influences beyond inherent anatomy, repetitive load, and abnormal motion.

CONCLUSIONS

Additional studies to define patterns of normal use and wear will provide data to better characterize CMC OA and opportunities for tailored treatment, including prevention, delay of progression, and joint arthroplasty.

Sensorimotor interventions and assessments for the hand and wrist: a scoping review

STUDY DESIGN

Scoping review.

INTRODUCTION

Sensorimotor deficits can impair function and may be present in individuals with common upper extremity conditions.

PURPOSE OF THE STUDY

To provide clinicians with an understanding of the usefulness of the assessments to evaluate sensorimotor function and the interventions reported in the literature to effect positive change in our patients with sensorimotor deficits affecting the hand and wrist.

METHODS

A systematic search produced seventeen studies involving sensorimotor retraining and assessment of sensorimotor performance for the upper extremity.

RESULTS

Sensorimotor interventions and assessments found in the literature vary in regards to their effectiveness in restoring sensorimotor function in subjects with a number of conditions that affect hand and wrist function.

CONCLUSIONS

There is a potential value of sensorimotor interventions for individuals with specific upper extremity conditions. There is a need for further studies to improve treatment of sensorimotor deficits and understanding of sensorimotor interventions.

Dynamic loading posture of the thumb: the Colditz Tear Test

The movement patterns one sees when loads placed on a joint are incrementally increased provides valuable insight as to how a joint functions during different everyday activities. This author describes a simple, yet effective method of assessing the thumb carpometacarpal joint as load demands increase. It may be used as an evaluative tool or as an adjunct to treatment.