The passive biomechanics of the thumb carpometacarpal joint: An in vitro study.

The thumb carpometacarpal (CMC) joint facilitates multidirectional motion of the thumb and affords prehensile power and precision. Traditional methods of quantifying thumb CMC kinematics have been largely limited to range-of-motion (ROM) measurements in 4 orthogonal primary directions (flexion, extension, abduction, adduction) due to difficulties in capturing multidirectional thumb motion. However, important functional motions (e.g., opposition) consist of combinations of these primary directions, as well as coupled rotations (internal and external rotation) and translations. Our goal was to present a method of quantifying the multidirectional in vitro biomechanics of the thumb CMC joint in 6 degrees-of-freedom. A robotic musculoskeletal simulation system was used to manipulate CMC joints of 10 healthy specimens according to specimen-specific joint coordinate systems calculated from computed tomography bone models. To determine ROM and stiffness (K), the first metacarpal (MC1) was rotated with respect to the trapezium (TPM) to a terminal torque of 1 Nm in the four primary directions and in 20 combinations of these primary directions. ROM and K were also determined in internal and external rotation. We found multidirectional ROM was greatest and K least in directions oblique to the primary directions. We also found external rotation coupling with adduction-flexion and abduction-extension and internal rotation coupling with abduction-flexion and adduction-extension. Additionally, the translation of the proximal MC1 was predominantly radial during adduction and predominantly ulnar during abduction. The findings of this study aid in understanding thumb CMC joint mechanics and contextualize pathological changes for future treatment improvement.

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.

In Vivo Kinematics of the Thumb Carpometacarpal Joint During Flexion and Abduction.

Background: Despite the movement of the thumb carpometacarpal joint has been studied, many unclarified points remain regarding the movement of this joint. The purpose of this study was to evaluate the in vivo kinematics of the thumb carpometacarpal joint during flexion and abduction using computed tomography images. Methods: The subjects were 9 healthy males. Computed tomography images were obtained in 4 equally-divided positions from maximum extension to maximum flexion, and maximum adduction to maximum abduction of the thumb. A three-dimensional model was constructed from these images, and the models of each position were superimposed with reference to the trapezium. The amount of angular change around the bone axes of first metacarpal bone and rotation axes were evaluated. Results: We found that the first metacarpal bone showed relatively simple behavior during abduction. However, during flexion, it exhibited a particular movement in which the amount of angular change of the metacarpal bone with respect to the trapezium rapidly increased with deep flexion. Conclusions: These results suggest that the thumb carpometacarpal joint exhibits a special movement during flexion, especially deep flexion.

Radial and palmar active range of motion measurement: reliability of six methods in healthy adults.

The current study aims to assess the reliability of 6 range-of-motion measurement methods for the thumb carpometacarpal joint: Pollexograph-thumb, Pollexograph-metacarpal, radius-metacarpal goniometry, intermetacarpal goniometry, intermetacarpal distance, and thumb-distal-interphalangeal distance. A senior hand surgeon, an experienced resident, and a less experienced research fellow evaluated the dominant hands of 29 healthy subjects. All 6 methods were performed for radial adduction, radial abduction, and palmar abduction, but only distance methods were measured for palmar adduction. Intrarater and interrater reliability were computed using intraclass correlation coefficient, standard error of measurement, and smallest detectable difference. Pollexograph-thumb method showed the highest active range of movement for radial adduction (12°) and abduction (71°), while all the other angular methods resulted in approximately 20° for radial adduction and 50° for radial abduction. Distance methods showed comparable mean results for radial and palmar range of motion (adduction/abduction): intermetacarpal distance (50 mm/60 mm) and thumb-distal-interphalangeal distance (50 mm/120 mm). Interrater reliability using the results of the intraclass correlation coefficient demonstrates that Pollexograph-thumb and Pollexograph-metacarpal showed excellent reliability for radial adduction and abduction, whereas Pollexograph-thumb method revealed the best reliability for palmar abduction. Moreover, thumb-distal-interphalangeal distance also showed excellent reliability for radial and palmar abduction. Conventional goniometry showed a large variety of reliability results, ranging from poor to excellent. No clinical benefit can be derived from assessing the palmar adduction. We found that the Pollexograph-thumb showed excellent reliability results throughout all measurements. Thumb-distal-interphalangeal-joint distance is especially valuable for assessing radial and palmar abduction.

Physiologic effects of long-term immobilization of the equine distal limb.

OBJECTIVE: To describe the effects of distal limb immobilization and remobilization in the equine metacarpophalangeal joint. STUDY DESIGN: Randomized, prospective experimental study. ANIMALS: Eight healthy, skeletally mature horses. METHODS: One forelimb of each horse was immobilized in a fiberglass cast for 8 weeks; this was followed by 12 weeks of a treadmill-based training program after the cast had been removed. Clinical examinations, radiography, computed tomography (CT), nuclear scintigraphy, MRI, and histomorphometry were used to examine the third metacarpal (MC3), proximal phalanx, proximal sesamoid bones, and associated soft tissues in each horse. Serum and synovial fluid were collected for biomarker analyses. RESULTS: Distal limb immobilization resulted in persistent lameness (P < .001), effusion (P = .002), and a decreased range of motion (P = .012) as well as radiographically visible fragments (P = .036) in the cast forelimb. Bone density was decreased (P < .001) in MC3 according to CT, and trabecular bone fluid was increased (P < .001) according to MRI in the cast forelimb. The cast forelimbs had a change (P = .009) in the appearance of the deep digital flexor tendon according to MRI immediately after removal of the cast. Numerous clinical, radiographic, CT, and MR abnormalities were visible at the end of the study period. CONCLUSION: Eights weeks of cast immobilization induced changes in bone, cartilage, and periarticular soft tissues that were not reversed after 12 weeks of remobilization. CLINICAL SIGNIFICANCE: Cast application should be used judiciously in horses with musculoskeletal injuries, balancing appropriate stabilization with potential morbidity secondary to cast placement.

A Three-dimensional Finger Motion Measurement System of a Thumb and an Index Finger Without a Calibration Process.

Various wearable systems have been investigated to measure hand motion, but some challenges remain. Many systems require a calibration process to map sensor signals to actual finger joint angles by the principle of measuring the length change of the finger, or bending sensors. Also, few studies have investigated how to measure thumb motion accurately using the wearable systems. This paper proposes an exoskeleton system with linear Hall sensors to measure three-dimensional hand motion without a calibration process. The calibration process is avoided by measuring finger joint angles through an absolute rotation measurement. A new wearing method with lower parts underneath the hand joints and rubber bands is proposed to fix the structure to the hand and adapt it for various hand sizes. As the thumb has a complex biomechanical feature at carpometacarpal (CMC) joint, a new measuring method of the CMC joint is proposed to directly calculate the orientation of the metacarpal. The prototype of the thumb and index finger was manufactured, and the performance was verified experimentally by using an optical motion capture system.

Complex thumb motions and their potential clinical value in identifying early changes in function.

BACKGROUND: Early diagnosis and treatment of osteoarthritis of the thumb allows for early interventions that may mitigate osteoarthritis progression and decrease severity later in life. Early identification of motion changes is limited by the clinical reliance on single planar measurements using goniometry. Multi-planar measurements using motion capture can provide insights into joint function and pathophysiology that cannot be obtained from single-plane goniometry measurements. Thus, the goals of this research were 1) to determine differences in thumb motions across three groups of participants (young healthy (n = 23), older healthy (n = 11), and those with carpometacarpal osteoarthritis (n = 24)) and 2) to determine if multi-planar motions provided additional movement information in comparison to standard planar measures. METHODS: In this study, a motion capture system was used to collect standard clinical ranges of motion and complex multi-planar tasks. Differences in motion patterns due to aging and osteoarthritis were identified. Motions tested included palmar adduction-abduction, radial adduction-abduction, metacarpophalangeal flexion-extension, interphalangeal flexion-extension, functional adduction-abduction, opposition, and circumduction. FINDINGS: Results indicated that motion capture was capable of detecting changes in carpometacarpal mobility that were not detected using standard approaches. Our results suggested that use of multi-planar measurements have the potential to identify changes that are indicators of early stages of osteoarthritis. INTERPRETATION: Early indicators are clinically useful as they will enhance patient treatment by permitting the application of treatment approaches sooner, potentially leading to reduced overall functional deficits.

Maximum Palmar Abduction Angle of the Trapeziometacarpal Joint in Healthy Subjects Can Be Evaluated Accurately Using a Radiograph-Based Measurement Technique.

In carpal tunnel syndrome, the abductor pollicis brevis, which is the primary muscle for the palmar abduction of the thumb, is almost inevitably impaired. The active palmar abduction of the thumb may be a better indicator of thumb disability. The authors aimed to establish a simple and accurate method to measure the angle of active palmar abduction of the thumb and to determine the maximum angle values in healthy women. Twenty-five women 20 to 21 years old with no disorder of the hand participated in this study voluntarily. Three measurement methods were tested. The first method was designed according to the Japanese Orthopaedic Association and the second method was designed according to the American Society of Hand Therapists; both use photographs to perform measurement calculations. In the third method, 2 orthopedic surgeons measured the same angle as that described in the second method on hand radiographs. Intra- and interobserver reliability were assessed for each method and described as interclass correlation coefficients. The first and third methods had strong inter- and intraobserver reliability. The second method had strong intraobserver reliability but medium interobserver reliability. The measurement obtained with the first method was significantly different from the values obtained by the second and third methods (almost double). Therefore, the authors regarded the third method as the most appropriate approach for measuring active palmar abduction of the thumb, which, in healthy individuals, yielded maximum values of 45.3°±6.4° and 44°±7° for the left hand and the right hand, respectively. [Orthopedics. 2020; 43(2):e95-e101.].

Comparison of arthrodesis and arthroplasty of Chinese thumb carpometacarpal osteoarthritis.

BACKGROUND: The thumb carpometacarpal (CMC) osteoarthritis is very common. Multiple methods are used to treat progressive thumb CMC osteoarthritis, among which trapeziometacarpal arthrodesis and trapezial excision with ligament reconstruction and tendon interposition (LRTI) are the most common. These two surgical treatment methods have received mixed reviews in previous studies in the west patients. This retrospective study studied the effects, advantages, and disadvantages of arthrodesis and arthroplasty for treating thumb carpometacarpal osteoarthritis in Chinese patients. METHODS: Between February 2012 and September 2017, 39 Chinese patients with stage II or III thumb carpometacarpal osteoarthritis underwent surgery (trapeziometacarpal arthrodesis in 22, trapezial excision with ligament reconstruction and tendon interposition in 17). Postoperative objective and subjective evaluations were performed. The objective evaluation involved grip strength, pinch strength, thumb abduction degree (palmar and radial), and Kapandji opposition scores. The subjective evaluation involved visual analog scale (VAS) and Disabilities of the Arm, Shoulder, and Hand (DASH) scores. RESULTS: Intergroup differences in pinch strength, thumb abduction degrees (palmar and radial), and Kapandji opposition scores were obvious, whereas those in grip strength, VAS score, and DASH score were not. CONCLUSION: In Chinese patients, both techniques relieved pain and improve grip strength. Arthrodesis displayed better pinch strength, while arthroplasty displayed better motor function. Patients were satisfied with the effects of both techniques.

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.

Quantitative analysis of in-vivo thumb carpometacarpal joint kinematics using four-dimensional computed tomography.

The purpose of this study was to define the normal thumb carpometacarpal joint kinematics in-vivo during opposition and abduction using four-dimensional computed-tomography in four volunteers. Movement of the metacarpal relative to the trapezium was quantified using both Euler and helical axis representations. Articular surface contact patterns were also analysed. The overall axis of rotation for the movement of opposition and abduction passes through the trapezium and the base of the proximal phalanx, respectively. An abrupt change in instantaneous axis of rotation at terminal opposition was found. Ligament modelling shows dorsoradial ligament becomes tauter towards terminal opposition, whereas anterior oblique ligament becomes more slack. These results support the existence of the 'screw-home' pivot at terminal opposition and the importance of the dorsoradial ligament for stability in this position. The normal reference set in this study can help establish a diagnostic tool for subtle carpometacarpal instability, or for evaluating efficacy of surgery.

Trapeziometacarpal stabilization through dorsoradial ligament reconstruction: An early post-surgery in vivo biomechanical analyses.

Ligament reconstruction can provide pain relief in patients with a painful, unstable, pre-arthritic trapeziometacarpal (TMC) joint. Imbrication of the dorsoradial ligament (DRL) has been proposed as a minimal invasive stabilization technique. It requires less invasive surgery than an Eaton-Littler technique and shows promising long-term clinical outcome. We used dynamic CT to objectively review the effects of the imbrication. Four patients with pain and laxity at the TMC joint, but without radiographic signs of osteoarthritis, were recruited. Dynamic CT scans were made during active thumb abduction-adduction, flexion-extension, and two functional grip tasks using a radiolucent jig. Scans of the patients were acquired before and 3 to 6 months after DRL reconstruction. Motion of each bone in the articular chain of the thumb was quantified. In addition, we mapped changes in the contact patterns between the articular facets during the entire thumb motion. After DRL imbrication, we found no overall decrease in MC1 movement in three out of four patients. Furthermore, no increase in TMC joint congruency, defined as proximity area size, was found for three out of four patients. Pre- and post-operative differences in congruency across different tasks were patient-dependent and relatively small. We demonstrated that, from a biomechanical perspective, there is high variability in post-operative outcome between patients that undergo identical surgical procedures performed by the same surgeon. A post-operative decrease in range of motion, increase in joint congruency or decrease in proximity area shift during thumb motion is not omnipresent. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2851-2864, 2018.

Evaluation of the pulley function of the hamulus of the hamate for the flexor tendons.

PURPOSE: The aim of this study was to measure the curvature radii of the finger flexor tendons on CT acquired using tendon conditions to examine whether the hamulus of the hamate functions as a pulley of the flexor tendon. METHODS: The subjects were 20 healthy volunteers (40 hands) (14 males and 6 females, mean age: 27.5 years old). Their hands were imaged in extension and flexion of the fingers on CT. The curvature radii of the little and middle finger flexor tendons at the hamulus of the hamate were calculated. RESULTS: The curvature radii of the little and middle finger flexor tendons were 24.8 ± 7.3 and 327.1 ± 343.9 mm in finger extension, respectively, and 21.3 ± 5.3 and 265.1 ± 202.9 mm in finger flexion, respectively. The curvature radius of the little finger flexor tendon was significantly smaller than that of the middle finger flexor tendon in both finger extension and flexion (P < 0.01). CONCLUSIONS: Our study suggested that the hamulus of the hamate functions as a pulley for the little finger flexor tendon.

Influence of age and gender on normative passive range of motion values of the carpometacarpal joint of the thumb.

STUDY DESIGN: Cross-sectional clinical measurement study. INTRODUCTION: The carpometacarpal (CMC) joint of the thumb is a complex joint making accurate measurement of range of motion (ROM) challenging. There are limited normative data available to base rehabilitative decisions, which is unfortunate as this joint is frequently affected by arthritis and is critical to hand function. PURPOSE OF THE STUDY: To provide passive ROM values for the first CMC joint and investigate the effects of age and gender. METHODS: Ninety-six healthy subjects were divided into 4 age groups of equal gender: 20-34, 35-49, 50-64, and 65+ years. Six-inch plastic universal goniometers were used to take 3 measurements of flexion, extension, and abduction of the dominant hand. RESULTS: Mean ROM values were 21.7 ± 6.8 degrees of flexion, 19.5 ± 5.7 degrees of extension, and 51.1 ± 5.5 degrees of abduction. There was a weak negative correlation (r = -0.22; P = .03) between age and abduction and a difference between 2 age groups. No other relationship or difference due to age, gender, or interactions reached significance. CONCLUSIONS: These normative ROM values for adults can be used by clinicians assessing patients for impaired motion at the CMC joint. No differences in flexion, extension, and abduction due to age and gender were supported, except for a small decrease (4.5°) in abduction in adults 65+ years compared with those of 35-49 years. LEVEL OF EVIDENCE: 3.

In Vivo 3-Dimensional Kinematics of Thumb Carpometacarpal Joint During Thumb Opposition.

PURPOSE: This study primarily aimed to demonstrate the screw-home rotation of the thumb carpometacarpal (CMC) joint and the function of surrounding ligaments during thumb oppositional motion. METHODS: A 3-dimensional kinematic analysis of the thumb CMC joint was conducted using data derived from computed tomography of 9 healthy volunteers. Scans were obtained in the neutral forearm and wrist position and the thumb in maximum radial abduction, maximum palmar abduction, and maximum opposition. The movements of the first metacarpal and the palmar and dorsal bases on the trapezium during thumb oppositional motion from radial abduction through palmar abduction were quantified using a coordinate system originating on the trapezium. In addition to the kinematic analyses, the length of virtual ligaments, including the anterior oblique, ulnar collateral, dorsal radial, dorsal central (DCL), and posterior oblique ligament (POL), were calculated at each thumb position. RESULTS: From radial abduction to opposition of the thumb through palmar abduction, the first metacarpal was abducted, internally rotated, and flexed on the trapezium. The palmar base of the first metacarpal moved in the palmar-ulnar direction, and the dorsal base moved in the palmar-distal direction along the concave surface of the trapezium. Although the DCL and POL lengthened, the lengths of other ligaments did not change significantly. CONCLUSIONS: During thumb oppositional motion, internal rotation of the first metacarpal occurred, with the palmar base rotating primarily with respect to the dorsal base. The DCL and POL may be strained in thumb functional positions. CLINICAL RELEVANCE: Kinematic variables indicated a screw-home rotation of the thumb CMC joint and the contribution of the dorsal ligaments to the stability of the rotation on the pivot point.

Trapeziometacarpal joint contact varies between men and women during three isometric functional tasks.

Trapeziometacarpal (TMC) joint osteoarthritis (OA) affects women two to six times more than men, and is influenced by stresses and strains in the cartilage. The purpose of this study was to characterise sex and age differences in contact area and peak stress location of the healthy TMC joint during three isometric tasks including pinch, grasp and jar twist. CT images of the hand from 50 healthy adult men and women were used to create a statistical shape model that was used to create finite element models for each subject and task. Force-driven simulations were performed to evaluate cartilage contact area and peak stress location. We tested for sex and age differences using Principal Component Analysis, linear regression, and Linear Discriminant Analysis. We observed sex differences in peak stress location during pinch (p = .0206), grasp (p = .0264), and jar twist (p = .0484). The greatest sex differences were observed during jar twist, where 94% of peak stresses in men were located in the centre compared with 50% in the central-volar region in women. These findings show that peak stress locations are more variable in women during grasp and jar twist than men, and suggest that women may employ different strategies to perform these tasks.

In vivo biomechanical behavior of the trapeziometacarpal joint in healthy and osteoarthritic subjects.

BACKGROUND: The contact biomechanics of the trapeziometacarpal joint have been investigated in several studies. However, these led to conflicting results and were mostly performed in vitro. The purpose of this study was to provide further insight on the contact biomechanics of the trapeziometacarpal joint by in vivo assessment of healthy and osteoarthritic subjects. METHODS: The hands of 16 healthy women and 6 women with trapeziometacarpal osteoarthritis were scanned in positions of maximal thumb extension, flexion, abduction and adduction during three isometric tasks (lateral key pinch, power grasp and jar twist) and in thumb rest posture (relaxed neutral). Three-dimensional surface models of the trapezium and first metacarpal were created for each thumb configuration. The articular surface of each bone was measured in the neutral posture. A computed tomography-based proximity mapping algorithm was developed to calculate the distance between opposing joint surfaces, which was used as a surrogate for intra-articular stress. FINDINGS: Distinct proximity patterns were observed across tasks with a recurrent pattern reported on the volar aspect of the first metacarpal. The comparison between healthy and arthritic subjects showed a significantly larger articular area, in parallel with a significant joint space narrowing and an increase in proximity area in arthritic subjects. We also observed severe articular deformations in subjects with late stage osteoarthritis. INTERPRETATION: This study has increased our insight in the contact biomechanics of the trapeziometacarpal joint during tasks and positions of daily life in healthy and arthritic subjects, which might contribute to a better understanding of the occurrence mechanisms of degenerative diseases such as osteoarthritis.

Assessment of normal trapeziometacarpal joint alignment.

The purpose of this study was to determine the alignment of the normal trapeziometacarpal joint and any changes in its alignment with age. Radial, dorsal and dorsoradial subluxation were measured on computerized tomographic scans in 50 joints of 50 adults aged 18 to 62. There were statistically significant correlations between increasing age and dorsoradial subluxation but no significant correlation with dorsal and radial subluxation. Significant dorsoradial subluxation occurs after 46 years of age in the normal trapeziometacarpal joint. A mean dorsoradial subluxation of 21% (range 14%-30%) can be considered normal in this age group.

Efficacy of Dorsoradial Capsulodesis for Trapeziometacarpal Joint Instability: A Cadaver Study.

PURPOSE: To test the biomechanical properties of the dorsoradial capsulodesis procedure. METHODS: Six cadaveric hands were used. After exposing the trapeziometacarpal (TMC) joint, we placed Kirschner wires in the distal radius and thumb metacarpal. The rotation shear test was then performed to test the joint axial laxity, and angular measurements using Kirschner wires as reference points were documented. The dorsoradial (DR) ligament and capsule were released, followed by the intermetacarpal (IM) ligament; angular measurements were obtained. Finally, the DR capsulodesis procedure was performed, and final measurements were obtained. Comparisons were made among the various stages of ligament integrity to determine the amount of stability provided by DR capsulodesis. RESULTS: All cadavers demonstrated axial laxity with transection of the DR ligament; an increase in stability was obtained after DR capsulodesis. Transection of the capsule and IM ligament caused increased laxity relative to the native joint (median, 24° and 35°, respectively, on rotational testing). After we performed DR capsulodesis, rotational stability improved by a median of 41° compared with DR ligament transection, 49° compared with DR and IM ligament transection, and 18° relative to the native joint. CONCLUSIONS: Dorsoradial capsulodesis restores rotational stability for TMC joint after division of the DR and IM ligaments. The stability achieved was statistically significant compared with both an intact native TMC joint and induced laxity of the TMC joint. CLINICAL RELEVANCE: The DR capsulodesis procedure may improve rotational stability to the TMC joint.