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.

BACKGROUND: Palmer type 1B triangular fibrocartilage complex (TFCC) tears are a common cause of distal radioulnar joint (DRUJ) instability. Unfortunately, the best surgical technique for TFCC reinsertion is still unknown, and up to a quarter of patients report instability after repair. The purpose of this systematic review of cadaver studies was to compare the biomechanical outcomes of different surgical techniques used for Palmer 1B TFCC tears.

METHODS: A systemic review of all cadaver studies published before January 2022 was performed using the PubMed and EMBASE databases. Only cadaver studies on reinsertion techniques for Palmer type 1B lesions were included. Biochemical outcome parameters evaluated were stability of the DRUJ and strength of the repair.

RESULTS: A total of 248 articles were identified. Five articles fulfilled the inclusion criteria. Four different surgical techniques were identified. In 3 studies, transosseous tunnel repair was tested and resulted in the most stable DRUJ and strongest TFCC repair compared with the suture anchor repair, the peripheral capsular repair, and the outside-in repair.

CONCLUSIONS: These results suggest that the transosseous tunnel repair might be a good technique for restoring DRUJ stability. However, more cadaver studies are needed to identify the most optimal technique.

The technical simplicity of the Darrach procedure may explain why it has been so popular. Excising the distal ulna, however, may have potentially undesired consequences to the biomechanics in two areas: the distal radioulnar and the ulno-carpal joints. These conjointly define the radio-ulno-carpal joint (RUCJ). The RUCJ is not a small and irrelevant articulation that can be removed without possibly paying a functional penalty. It is an important link of the antebrachial frame that provides stability to the distal forearm and the carpus. This article revisits the mechanisms by which some ligaments and muscles ensure that all forces about and within the RUCJ are dealt with efficiently.

OBJECTIVE: Focal cartilage injuries, and posttraumatic osteoarthritis (OA) in the wrist are likely common and a cause of wrist pain. To estimate the incidence of cartilage lesions and to understand the pathomechanisms leading to wrist cartilage injuries and OA, a literature review on the subject was performed combined with a presentation of one of the authors' own experience.

DESIGN: This study includes a literature review of the topic. As a comparison to the review findings, the observations of one of the authors' consecutive 48 wrist arthroscopies, were assessed. PubMed, Scholar, and Cochrane databases were searched using the keywords "cartilage injury AND wrist AND treatment" and "wrist AND cartilage AND chondral AND osteochondral AND degenerative OA."

RESULT: A total of 11 articles, including 9 concerning chondral and osteochondral repair and treatment and 2 regarding posttraumatic OA, were retrieved. The cartilage repair treatments used in these articles were drilling, osteochondral autograft, juvenile articular cartilage allograft, and chondrocyte implantation. One article displayed concomitant cartilage injuries in displaced distal radius fractures in 32% of the patients. The review of our findings from a 1-year cohort of wrist arthroscopies showed 17% cartilage injuries.

CONCLUSION: There is a lack of knowledge in current literature on cartilage injuries and treatment, as well as posttraumatic OA in the wrist. Cartilage injuries appear to be common, being found in 17% to 32% of all wrist arthroscopies after trauma, but no guidelines regarding conservative or surgical treatment can be recommended at the moment. Larger prospective comparative studies are needed.

INTRODUCTION: Traumatic injuries of the triangular fibrocartilage complex (TFCC) are frequent reasons for ulnar wrist pain. The assessment of the extent of articular disc (AD) degeneration is important for the differentiation of acute injuries versus chronic lesions.

MATERIALS AND METHODS: The AD of the TFCC of eleven human cadaver wrists was dissected. Degeneration was analyzed according to the grading of Krenn et al. Hematoxylin-eosin was used to determine the tissue morphology. Degeneration was evaluated using the staining intensity of alcian blue, the immunohistochemistry of the proteoglycan versican and the immunoreactivity of NITEGE, an aggrecan fragment.

RESULTS: The staining homogeneity of HE decreased with higher degeneration of the AD and basophilic tissue areas were more frequently seen. Two specimens were characterized as degeneration grade 1, five specimens as grade 2, and four specimens as grade 3, respectively. Staining intensity of alcian blue increased with higher degeneration grade of the specimens. Immunoreactivity for NITEGE was detected around tissue fissures and perforations as well as matrix splits. Immunoreactivity for versican was found concentrated in the tissue around matrix fissures and lesions as well as loose connective tissue at the ulnar border of the AD. Specimens with degeneration grade 2 had the strongest immunoreactivity of NITEGE and versican. Cell clusters were observed in specimens with degeneration grade 2 and 3, which were stained by alcian blue and immunoreactive for NITEGE and versican. Increasing age of the cadaver wrists correlated with a higher degree of degeneration (p < 0.0001, r = 0.68).

CONCLUSIONS: The fibrocartilage of degenerated ADs contains NITEGE and versican. The amount of the immunoreactivity of these markers allows the differentiation of degenerative changes into three grades. The degeneration of the AD increases with age and emphasizes its important mechanical function.

STUDY DESIGN: Descriptive reliability study.

INTRODUCTION: A well-functioning wrist requires sufficient range of motion accompanied by adequate strength in every movement and direction-factors that are not regularly measured simultaneously in patients with wrist problems today. The ISOmetric Power device (ISOP) is a new instrument that measures isometric wrist force in all six directions of motion, but its intrarater reliability in a healthy population has not yet been evaluated.

PURPOSE OF THE STUDY: The purpose of this study was to perform an intrarater reliability test of the ISOP in healthy participants.

METHODS: Thirty-two healthy study participants (16 women/16 men; mean age 38.3 years; SD 6.5) were included. With a standardized testing protocol, the three planes of wrist motion- wrist flexion/extension, radial/ulnar deviation, pro/supination-were measured at one time interval (T1) and repeated after one week (T2). The results were analyzed using the intraclass correlation coefficient (ICC). A paired-samples t-test was also performed to determine if a statistically significant difference (P < .05) existed between the first and the second test values. Measurements with Jamar Dynamometer were performed at both time intervals, for internal control of measurement intrarater reliability.

RESULTS: Excellent correlations (ICC: 0.90-0.99) were found for all test-retests performed. The lowest value (ICC: 0.90) was seen for supination and the highest value (ICC: 0.99) for flexion of the left hand. No statistically significant differences were found in any of the pairs (P > .05) in terms of test-re-test, which additionally strengthen the correlation between the first and second test values.

DISCUSSION: Contrary to the Jamar Dynamometer, the ISOP is not designed for measuring grip strength, but for assessing the isometric muscle force in flexion, extension, pronation, supination, and radial and ulnar deviation. A systematic review has reported a moderate to strong correlation between isometric strength and dynamic performances. Thus, the ISOP is a more complete and applicable instrument for evaluating the functional strength in different directions in the upper extremity.

CONCLUSIONS: The ISOmetric Power device shows excellent intrarater reliability and is proposed to be a possible valuable wrist strength assessment tool to aid in both diagnostics and outcome measures of wrist and upper extremity disorders.