Étude anatomique de l’innervation de l’articulation trapézo-métacarpienne

Innervation of thumb carpometacarpal joint: implications for diagnostic block and denervation procedures

INTRODUCTION

Osteoarthritis (OA) of the thumb carpometacarpal (CMC) joint is a common disorder that negatively impacts hand function. Denervation of the thumb CMC joint has emerged as a viable treatment option. However, the innervation pattern of the thumb CMC joint is controversial. Therefore, the objective of this study was to identify the articular branches supplying the thumb CMC joint and to document their relationship to anatomical landmarks to provide the foundation for image-guided diagnostic block and denervation procedures.

METHODS

In 10 formalin-embalmed upper limb specimens articular branches supplying the thumb CMC joint were dissected from their origin to termination. A frequency map documenting the number of articular branches was generated. The frequency map enabled visualization and comparison of the relative area of innervation of the thumb CMC joint by each articular branch.

RESULTS

The thumb CMC joint received innervation from six nerves. These were the deep branch of ulnar nerve (DBUN), dorsal articular nerve (DAN) of the first interosseus space, thenar branch of median nerve (TBMN), palmar cutaneous branch of median nerve (PCBMN), lateral antebrachial cutaneous nerve (LACN) and superficial branch of the radial nerve (SBRN) and/or their branches. Each nerve was found to innervate different aspects of the joint. The DBUN and DAN were found to innervate the posteromedial aspect of the thumb CMC joint, the TBMN and PCBMN anterior/anteromedial aspects, LACN posterolateral/lateral/anterior aspects and SBRN posterolateral/anterolateral aspects.

CONCLUSIONS

The thumb CMC joint was innervated by articular branches originating from the SBRN, DAN, LACN, PCBMN, TBMN and DBUN. The documented anatomical relationships provide the foundation to inform selective diagnostic block and denervation of the thumb CMC joint. Further investigations are needed to assess the clinical implications of the current study.

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.

First Carpometacarpal Joint Denervation: A Systematic Review

PURPOSE

The first carpometacarpal (CMC) joint is a frequent location of osteoarthritis in the hand. The denervation of the first CMC joint has gained traction as a viable treatment for CMC arthritis. This study reviewed literature on CMC denervation for first CMC arthritis.

METHODS

A systematic review of papers and abstracts was conducted. The preferred reporting items for systematic reviews and meta-analyses guidelines were followed. Articles including the results of CMC denervation were included. We compiled data on patient demographics, preoperative testing, intraoperative technique, and postoperative outcomes. Anatomic literature was also reviewed to assess agreement on the innervation of the first CMC joint.

RESULTS

Six anatomic studies and 9 clinical studies were included in this systematic review. Pinch strength, grip strength, and Kapandji scores increased on average in patients. Pain relief was noted on average in patients in 5 studies that reported pain outcomes. In studies that reported postoperative complications, the most frequent complications were radial paresthesias, hypoesthesia dorsal and/or distal to the surgical site, and wound infection.

CONCLUSIONS

The innervation of the CMC joint is controversial. This is reflected in clinical practice, wherein varied surgical approaches are used. Carpometacarpal denervation shows promise as an option to treat patients with CMC arthritis without joint instability, but its results vary. Additional clinical studies with longer-term follow-up and control groups are necessary to better determine its longevity and efficacy.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

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.

Innervation of digital joints: an anatomical overview

INTRODUCTION

The innervation of the digital joints as well as the anatomical relationships of the articular branches is present in this anatomical work to determine the technical feasibility of a selective and efficient denervation of the digital joints.

MATERIALS AND METHODS

A study of 40 distal interphalangeal (DIP), 40 proximal interphalangeal (PIP), 50 metacarpophalangeal (MCP), 10 interphalangeal (IP) of the thumb, and 10 trapezo-metacarpophalangeal (TMC) joints was performed on ten hands. Under magnification and a proper surgical approach, we collected the course, the source origin, the number of articular nerve branches, and their caliber.

RESULTS

In total, 118 nerve branches arising from the proper palmar digital nerves were found on 10 DIP of each dissected long finger (n = 40). A total of 226 nerve branches were found on 10 PIPs of each long finger (n = 40), of which 204 branches (90.3%) had a palmar origin. Dorsal innervation was found for the ring and little finger, originating from the dorso-ulnar digital nerve. 212 branches were found on 10 MCP of long fingers (n = 40), including 87 branches of palmar origin (41.1%), 107 branches of dorsal origin (50.4%), and 18 branches of the motor branch of the ulnar nerve (8.5%). 42 articular branches directed to the TMC joint (n = 10) were found. 13 branches (31%) originated from the anterior sensory branch of the radial nerve, 13 branches (31%) originated from the lateral cutaneous nerve of the forearm, 5 branches (12%) originated from the palmar cutaneous branch of the median nerve, and 11 (26%) branches originated from the thenar branch of the median nerve. The involvement of the sensory anterior branch of the radial nerve was always present for the innervation of each TMC.

DISCUSSION AND CONCLUSION

Our research shows that finger joints receive their primary innervation from small branches of the digital nerves with the exception of the MCP joint and the TMC joint. To obtain an efficient and a selective digital denervation for articular pain relief, it is necessary to plan the best surgical approach and it is crucial to recognize the articular nervous branch localization and source.

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.

Total trapeziometacarpal joint arthroplasty using wide awake local anaesthetic no tourniquet

We conducted a descriptive study of 50 consecutive cases of total trapeziometacarpal joint arthroplasty by one surgeon using wide awake local anaesthetic no tourniquet to assess the usefulness and reliability of the anaesthesia, any adverse effects and patient acceptance. No difference was found when comparing the duration of surgery with 50 cases of total trapeziometacarpal joint arthroplasty inserted in a bloodless field under general or regional anaesthesia by the same surgeon. Wide awake local anaesthetic no tourniquet was found to be useful in providing adequate anaesthesia and haemostasis, and to be reliable and safe with no adverse effects. Patient satisfaction was high with 100% willing to repeat. Overall, wide awake local anaesthetic no tourniquet was a satisfactory method of anaesthesia for trapeziometacarpal joint arthroplasty with the potential for significant benefits to both patient and surgeon compared with traditional general anaesthesia and regional block.Level of evidence: II.

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.

Effectiveness of Superficial Radial Nerve Block on Pain, Function and Quality of Life in Patients With Hand Osteoarthritis: A Prospective, Randomized and Controlled Single-Blind Study

Objectives

This study aims to investigate the effects of ultrasound-guided superficial branch of the radial nerve block on pain, function and quality of life in patients with hand osteoarthritis.

Patients and methods

In this prospective, randomized and controlled single-blind study, 50 female patients (mean age 59.0±5.1 years; range, 46 to 64 years) diagnosed with hand osteoarthritis were randomized into two groups. Group 1 (n=25) was administered an ultrasound-guided superficial branch of the radial nerve injection (with a combination of 2 mL 0.25% bupivacaine and 1 mL methylprednisolone acetate) + exercise, while group 2 (n=25) only exercised. Patients were assessed with a visual analog scale for pain, hand grip strength, finger grip strength, Quick Disability of the Arm, Shoulder and Hand questionnaire, Duruöz Hand Index and Short-form 12. Data were obtained before treatment (W0), in the second week after treatment (W2) and in the fourth week after treatment (W4).

Results

In group 1, a statistically significant improvement was obtained in all parameters at both W2 and W4 compared to the values recorded at W0 (p<0.05). In group 2, a statistically significant improvement was observed only in the parameters of hand grip strength and finger grip strength at W2 and W4 (p<0.05). A comparison of the scores of the two groups showed statistically significant superior improvement in group 1 in all parameters at both W2 and W4 (p<0.05).

Conclusion

The findings of our study showed that an ultrasound-guided superficial branch of the radial nerve block combined with exercise is a significantly superior treatment to exercise-only regarding the improvements in the parameters of pain, function and quality of life in hand osteoarthritis patients.

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.

Innervation patterns of thumb trapeziometacarpal joint ligaments

PURPOSE

The human thumb trapeziometacarpal (TM) joint is a unique articulation that allows stability during pinch and grip and great degrees of mobility. Because the saddle-shaped articulating surfaces of the TM joint are inherently unstable, joint congruity depends on the action of restraining ligaments and periarticular muscles. From other joints, it is known that proprioceptive and neuromuscular joint stability depend on afferent information from nerve endings within ligaments. We hypothesize that the TM joint ligaments may similarly be innervated, indicating a possible proprioceptive function of the joint.

METHODS

We harvested 5 TM joint ligaments in entirety from 10 fresh-frozen cadaver hands with no or only minor signs of osteoarthritis and suture-marked them for proximal-distal orientation. The ligaments harvested were the dorsal radial, dorsal central, posterior oblique, ulnar collateral, and anterior oblique ligaments. After paraffin-sectioning, we stained the ligaments using a triple-antibody immunofluorescent technique and analyzed them using immunofluorescence microscopy.

RESULTS

Using the triple-stain technique, mechanoreceptors could be classified as Pacinian corpuscles, Ruffini endings, or Golgi-like endings. The 3 dorsal ligaments had significantly more nerve endings than the 2 volar ligaments. Most of the nerve endings were close to the bony attachments and significantly closer (P = .010) to the metacarpal insertion of each ligament. The anterior oblique ligament had little to no innervation in any of the specimens analyzed.

DISCUSSION

The TM joint ligaments had an abundance of nerve endings in the dorsal ligaments but little to no innervation in the anterior oblique ligament. The Ruffini ending was the predominant mechanoreceptor type, with a greater density in the mobile metacarpal portion of each ligament.

CLINICAL RELEVANCE

Presence of mechanoreceptors in the dorsal TM joint ligaments infers a proprioceptive function of these ligaments in addition to their biomechanical importance in TM joint stability.

Immunofluorescent triple-staining technique to identify sensory nerve endings in human thumb ligaments

Ligament innervation purportedly plays a critical role in stability, proprioception and pathology of joints with minimal bony constraints. The human thumb carpometacarpal (CMC) joint is such a joint: with a complex saddle configuration and wide circumduction, its constraint is primarily ligamentous and it is prone to osteoarthritis. CMC reconstruction is the most commonly performed arthritis surgery in the upper extremity. Little, however, is known about CMC ligament innervation. We describe a novel triple-staining immunofluorescence technique using the markers for low-affinity neurotrophin receptor p75, the pan-neuronal marker protein gene product (PGP) 9.5 and 4',6'-diamidino-2-phenylindole (DAPI) to simultaneously detect and differentiate between specific sensory nerve endings: the Pacini corpuscles, the Ruffini endings and nerve fascicles. Five primary CMC ligaments (dorsal radial, dorsal central, posterior oblique, anterior oblique and ulnar collateral ligaments) were harvested from 10 fresh-frozen human cadaver hands. Following paraffin sectioning, each ligament was stained using a triple-stain technique and imaged with fluorescence microscopy. Multidimensional acquisition permitted simultaneous capture of images at different wavelengths. Pacini corpuscles were distinguished by their distinct p75 immunoreactive capsules, and Ruffini endings by their overlapping p75 and PGP9.5 immunoreactive dendritic nerve endings. Simultaneous use of PGP9.5, p75 and DAPI immunofluorescence to analyze innervation patterns in human ligaments provides descriptive analysis of staining patterns and receptor structure as well as clues as to the proprioceptive function of CMC ligaments and the joint as a whole. Our novel findings of CMC ligament innervation augment the study of normal and pathological joint mechanics in this joint so prone to osteoarthritis.