Trapeziometacarpal Ligaments Biomechanical Study: Implications in Arthroscopy

[Base-of-thumb osteoarthritis: aspects to be considered with the indication of trapeziectomy and CMC I prosthesis]

Base-of-thumb osteoarthritis is the most frequent osteoarthritis of the hand requiring surgical treatment, although conservative treatment options should be exhausted before surgery. If the wear process progresses with continuing pain-related loss of thumb function, thus leading to a loss of function of the whole hand, surgical treatment is indicated. In 1947, Gervis published results after trapeziectomy and heralded the development of a multitude of different surgical procedures. The long time needed for rehabilitation is a major problem of trapeziectomy with or without tendon interposition and/or suspension. After the implementation of the first CMC I prosthesis by De la Caffiniere 50 years ago, a rapid development took place, leading to the current modular bipolar implants. Especially in the German-speaking world, there is still some scepticism regarding these prostheses, which is why this review aims to illuminate both surgical procedures with a special focus placed on the aspects of indication.

Trapeziometacarpal Dislocations in Pediatric Age, Is There a Better Treatment? Series of Cases and a Systematic Review

(1) Background: Dislocations of the trapeziometacarpal joint (TMC) are uncommon in children and adolescents. Only a few isolated cases are reported in the literature. Therapeutic guidance is minimal and inconclusive. (2) Methods: The authors present four patients treated for this unusual lesion. We evaluated the evolution according to treatment, age, patient activity, and quickDASH. Despite the clear limitation of the small number of patients, it is relevant to try to better understand this lesion and its evolution. A systematic review of the literature was also conducted. (3) Results: This is the largest published series of TMC dislocations in children and adolescents. Patients included a 12-year-old girl treated conservatively with a poor quickDASH; a 9-year-old girl treated surgically with the Eaton-Littler technique for a new dislocation with a partially modified quickDASH; a 13-year-old boy with two necessary closed reductions for a new dislocation and a very good final quickDASH; and a 12-year-old boy treated with closed reduction and percutaneous fixation with excellent final results with quickDASH. (4) Conclusions: In the absence of scientific evidence, conservative treatment and ligament reconstruction did not provide good functionality. In contrast, closed reduction with percutaneous fixation provided excellent results. Therefore, the authors would recommend closed reduction and percutaneous needle fixation as an elective method to treat TMC dislocations in pediatric and adolescent patients.

The trapeziometacarpal screw home torque mechanism as a clinical indicator of the posterior joint ligament complex integrity: A cadaveric investigation

BACKGROUND

To date, no clinical test provides specific objective information on the integrity of key ligamentous support of the trapeziometacarpal (TMC) joint.

PURPOSE

To examine the potential of the TMC joint screw home torque mechanism (SHTM) in estimating the integrity of the posterior ligament complex in older adult population. STUDY DESIGN: Cross-sectional laboratory-based study.

METHODS

Twenty cadaver hands presenting with various degrees of TMC joint degradation ranging from none to severe osteoarthritis (OA) were radiographed in multiple positions to establish their degeneration status, joint mobility, and amount of dorsal subluxation at rest and with the application of the SHTM. Comparisons and correlations between degeneration status, joint mobility, subluxation reduction and ligament status obtained from dissection were calculated.

RESULTS

No significant statistical correlation was demonstrated with the subluxation reduction ratio of the SHTM and the combined ligament complex value however, a moderate negative correlation was found with dorsal central ligament injury at 21 Nm (τb = -0.46, p < 0.05) and 34 Nm (τb = -0.45, p < 0.05). A statistically significant reduction of radial subluxation of the TMC joint was observed between the subluxation at rest (M = 5.2, SD = 1.9) and subluxation with SHTM of 21 Nm (M = 4.4, SD = 2.4), t (19) = 3.2, p = 0.01, 95% CI [0.3, 1.4] and subluxation with SHTM of 34 Nm (M = 4.3, SD = 2.6), t (19) = 2.6, p = 0.02, 95% CI [0.2, 1.5].

CONCLUSION

Our results did not support the SHTM as indicator of the TMC posterior ligament complex integrity however, it demonstrated 100% stabilization effect with non-arthritic TMC population.

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.

Influence of differences in bone morphology on the distribution patterns of subchondral bone density across the trapeziometacarpal joint

We aimed to clarify the effects of morphological patterns of the trapezium and first metacarpal on the distribution of subchondral bone density across the articular surface of the trapeziometacarpal (TMC) joint using computed tomography osteoabsorptiometry. Thirty-three patients with normal TMC joints were evaluated. The percentages of the high-density areas in the radial-dorsal and ulnar-volar regions of the trapezium were significantly higher than that in the ulnar-dorsal region, and that of the ulnar-dorsal region of the first metacarpal was significantly lower than in the other three regions. The percentage of the high-density area of the radial-dorsal region of the trapezium and trapezial inclination (TI) showed a significant positive correlation, and the percentages of the high-density areas in the ulnar-dorsal and ulnar-volar regions had significant negative correlations with TI at the articular surface of the first metacarpal. These results indicate that bony morphologic differences in the trapezium affect the distribution pattern of subchondral bone density through the TMC joint.

Arthroscopically Assisted Eaton-Littler Trapeziometacarpal Ligamentoplasty

Background  Eaton-Littler ligamentoplasty has proven its efficacy in the treatment of trapeziometacarpal (TMC) instability. Description of Technique  In this article, we describe the arthroscopically assisted Eaton-Littler ligamentoplasty through two clinical cases. Patients and Methods  Arthroscopy is used to accurately place the metacarpal bone tunnel and pass the slip of flexor carpi radialis tendon in the latter. This procedure avoids soft-tissue dissection and could improve the outcome of this well-known surgery. Results  The two clinical cases showed good short-term outcome with a decrease of pain and good function. Conclusions  Arthroscopy to assist Eaton-Littler TMC ligamentoplasty is technically feasible, allowing a less invasive surgery. A larger prospective controlled study with a longer term outcome is mandatory to assess the real advantages of this modified procedure.

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.

First Carpometacarpal Joint Instability: Dorsal Ligament Reconstruction

The first carpometacarpal (CMC-I) joint has an elaborate ligamentous support. Recent evidence has demonstrated that the dorsal ligament group is imperative for joint stability and that CMC-I joint instability may occur as a consequence of trauma and ligamentous laxity, and other conditions, with possible CMC-I subluxation and the development of osteoarthritis. Although various surgical techniques have been introduced for the treatment of ligamentous CMC-I instability, the Eaton-Littler reconstruction has been regarded as the gold standard. It is widely accepted that impaired hand function may still be present following the reconstruction of the CMC-I joint ligaments, demonstrating the existing limitations of current surgical techniques. In this paper, a novel extra-articular technique relating to CMC-I joint instability and focusing on the dorsal ligament group is described. A graft taken from the abductor pollicis longus tendon is utilized to reconstruct the dorsal radial ligament and posterior oblique ligament. This technique may provide a less invasive alternative than the gold standard procedure and the hypothesis is that it will lead to a better outcome.

The Effect of the Joint Capsule and Anterior Oblique Ligament on Dorsal Subluxation of the First Metacarpal During Key Pinch

Laxity of the anterior oblique ligament (AOL) and/or the dorsoradial ligament (DRL) are believed to contribute to the progression of osteoarthritis in the trapeziometacarpal joint through increased dorsal subluxation. Stress radiographs during functional tasks, such as key pinch, can be used to evaluate such joint instability. Cadaveric experiments can explore joint contact pressures as well as subluxation under varying conditions, to gain knowledge about joint mechanics. The disturbance of supporting tissues, such as the joint capsule, during experiments may affect the recorded stability of the joint. To evaluate potential effects of opening the joint capsule and severing the AOL, eleven cadaveric specimens were rigged to simulate key pinch. An anteroposterior (AP) radiograph of the hand was recorded for each specimen while intact, after partially opening the joint capsule and after sectioning the AOL. First metacarpal subluxation levels were compared between the intact joint, partially open joint capsule, and sectioned AOL. Neither opening the joint capsule nor cutting the AOL had a statistically significant effect on metacarpal subluxation. The results indicate that partially opening the joint capsule has a negligible effect on joint mechanics and support recent studies that postulate that the AOL plays a less substantial role in preventing subluxation.

Short-Term Results after Total Trapeziectomy with a Poly-L/D-Lactide Spacer

Background  Proximal migration of the first metacarpal can be seen after total trapeziectomy and various techniques have been described to prevent this subsidence. Purpose  We hypothesized the insertion of a poly-L/D-lactide spacer to prevent proximal migration of the first metacarpal without the need of an additional ligament reconstruction, allowing early mobilization and less demanding rehabilitation. Patients and Methods  Ten thumbs were treated with a total trapeziectomy and insertion of a poly-L/D-lactide scaffold. Clinical and radiological evaluation was performed after 6 months and 1 year. Patient satisfaction, pain, Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score, mobility of the thumb, and strength were assessed. Results  Pain according to the visual analog scale decreased ( p  = 0.01) and QuickDASH score decreased ( p  = 0.02) significantly after 1 year. Radiological evaluation after 12 months showed a collapse of the scaphometacarpal distance of 45% ( p  = 0.01). Osteolysis of the distal scaphoid pole and/or proximal metacarpal was seen in 6 out of 10 cases. Because of the osteolysis, the use of the poly-L/D-lactide scaffold was discontinued in our practice. Conclusion  In this limited series, total trapeziectomy with the use of the poly-L/D-lactide scaffold provides significant pain reduction and improvement of overall function. Radiographic evaluation shows significant collapse of the scaphometacarpal distance after 1 year and frequent signs of osteolysis. We do not encourage the use of the poly-L/D-lactide scaffold with total trapeziectomy before long-term clinical and radiological follow-ups of the osteolysis are available.