Unilateral congenital aplasia of the scaphoid and dysplasia of the trapezium (a case report)]

Aplasia of the carpal scaphoid bone in association with dysplasia of the trapezium is a rare disorder. A right-handed, 66 years old male, suffering from a trapeziometacarpal arthritis on the right side is reported. X rays, MRI and CT-scan reveal an absence of scaphoid and a dysplasia of the trapezium. The lunate remains in place on the radius but is oriented in dorsi flexion. The capitate is dorsally and radially subluxated. Trapezium inclination of the joint at the base of the first metacarpal (trapezial tilt) is 32 degrees greater than on the opposite side which is normal (48 degrees). Radial styloid is hypoplasic. The scaphoid fossa is not covered with cartilage and subchondral sclerotic bone. The intercarpal joints show no trace of arthritis. There are no other deformation on the radial segment of the hand and the forearm. This congenital absence of scaphoid remains asymptomatic and well tolerated excepting the dysplasic trapeziometacarpal joint.     

Anatomical study of the normal and degenerative articular surfaces on the first carpometacarpal joint]

Specimens of 138 first carpometacarpal joints (CMJ) from cadavers consisting of 59 females and 79 males and averaging 68.8 years of age were grossly evaluated and morphological measurements were performed. Macroscopic degeneration of cartilage surface was noted in the metacarpus of 97 hands and trapezium of 73 hands. 1) Morphological measurements of normal articular surfaces showed that metacarpal concave depth was shallower in the female than in the male and trapezial convex height was flatter in the female than in the male. 2) The degeneration of the articular surface was more often observed in the metacarpal joint than the trapezial joint, and the degree of degenerative changes on each articular surface was greater in the female than in the male. 3) In Grade I, the degeneration of the cartilage surface was observed both in the radial and ulnar facets of the trapezium and in the dorsal and palmar facets of the metacarpus. 4) As the degeneration progressed in both sexes, the trapezial concavity became deeper and its convexity became flatter than normal. On the other hand, the metacarpal concavity was flatter and its convexity was higher than normal. Moreover, these changes were more apparent in the female than in the male.     

Material properties of the trapezial and trapeziometacarpal ligaments

Destabilization of the trapezium from its normal orientation with respect to the trapezoid, second metacarpal, and thumb metacarpal leads to incongruity at the trapeziometacarpal (TMC) joint. Abnormal shear forces may eventually result in TMC joint arthritis. By determining the relative stiffness and strength of the ligaments that stabilize this joint, one may infer their role in providing stability to the TMC joint. This study addresses the material properties of the ligaments stabilizing the trapezium and TMC joint to better understand the mechanics and kinematics of this joint. Fresh-frozen cadaveric hands (10 males and 10 females) were used to obtain bone-ligament-bone complexes from the dorsal and volar trapeziotrapezoid ligaments, dorsal and volar trapezio-second metacarpal ligaments, anterior oblique ligament, dorsoradial ligament, and trapezio-third metacarpal (T-III MC) ligament. The following material properties were derived from our data: ultimate load, ultimate stress (normalized failure load), ultimate strain (percent elongation), stiffness, toughness (energy to failure), and hysteresis. The dorsoradial ligament demonstrated the greatest ultimate load and toughness (energy to failure). The T-III MC ligament demonstrated the greatest ultimate stress (normalized failure load) and stiffness. The anterior oblique ligament demonstrated the least stiffness and the greatest hysteresis. The material properties of capsuloligamentous structures may be a good indicator of their importance to joint stability. Using these criteria we conclude that the T-III MC and dorsoradial ligaments are important stabilizers of the trapezium and TMC joint, respectively. These two ligaments were found to be the strongest, stiffest, and toughest ligaments, while the anterior oblique ligament was relatively weak and compliant. The dorsal trapezio-second metacarpal, volar trapezio-second metacarpal, and T-III MC ligaments were all relatively strong and are anatomically aligned to function as tension bands to restrain the trapezium against cantilever bending forces applied to it by the thumb during key or tip pinch.     

Treatment of a symptomatic trapezial dysplasia with metacarpal instability following thumb metacarpal lengthening with an addition-subtraction osteotomy

The most important problem of trapezial dysplasia with thumb metacarpal instability is of bony origin. Together with the progressive capsuloligamentous decompensation it evolves in a progressive adduction deformity of the thumb metacarpal secondary to the dysplasia of the trapezium with its increased articular slope. The addition-subtraction osteotomy restores the anatomy combining two techniques: an abduction-extension osteotomy of the first metacarpal to correct the axis of the first metacarpal and an opening wedge osteotomy of the trapezium to reorientate the trapezial saddle. We present a case of an addition-subtraction osteotomy in a case of symptomatic trapezial dysplasia with metacarpal instability following a thumb metacarpal lengthening in a severely mutilated hand. This technique was especially effective in reducing the instability and pain but mainly in maintaining mobile the only remaining joint of the thumb.     

Kinematics of the normal trapeziometacarpal joint

Motion of the trapeziometacarpal joint was studied in 12 hands from fresh human cadavera. By use of a magnetic tracking system, a full range of motion of the first metacarpal was analyzed with respect to a defined trapezial coordinate system. The traces of the reference points on the head and base of the first metacarpal were monitored, and the instantaneous centers of rotation were calculated. During circumduction, the reference points on the head and base followed elliptical paths but in opposite directions. The average instantaneous center of circumduction was at approximately the center of the trapezial joint surface. In flexion-extension, the axis of rotation was located within the trapezium, and the path of the head was identical to the path of the base. In abduction-adduction, the axis of rotation was located distal to the trapezium within the base of the first metacarpal, and the base and head moved in opposite directions. There was no single center of rotation: rather, instantaneous motion occurred reciprocally between these centers of rotation within the trapezium and metacarpal base in the normal thumb. This changing instantaneous center of rotation results in a unique pattern of motion which is related to congruent, tightly constrained joint surfaces of two reciprocal saddle joints and to precisely positioned extraarticular ligaments.     

Effects of the deep anterior oblique and dorsoradial ligaments on trapeziometacarpal joint stability

PURPOSE: Osteoarthritis of the trapeziometacarpal (TMC) joint of the thumb affects as many as 25% of postmenopausal women and 5% of middle-aged men. This study investigated the relative contribution of the dorsoradial ligament (DRL) and the deep anterior oblique ligament (dAOL) to the stability of the TMC joint. This knowledge will improve our understanding of the pathomechanics of osteoarthritis at the base of the thumb and may help to design novel reconstructive surgical procedures. METHODS: Seventeen intact cadaver hands were dissected to reveal the DRL and dAOL. Either the DRL or dAOL was transected randomly, physiologic muscle loads were applied to simulate lateral key pinch or thumb opposition, or a 3-dimensional magnetic tracking system was used to record the position of the thumb metacarpal relative to the trapezium. The differences in the 3-dimensional positions between the control and transected states were determined. RESULTS: In lateral pinch, transection of the DRL resulted in a mean increased 3-dimensional translation of 1.3 mm, whereas transection of the dAOL resulted in a mean increased 3-dimensional translation of 0.6 mm. Statistically significant 2-dimensional findings in lateral pinch after transecting the DRL or dAOL included an increased palmar subluxation of 0.3 mm and 0.2 mm, an increased radial (1.0 mm) and ulnar (0.3 mm) translation, and an increased pronation of 4.1 degrees and 2.4 degrees, respectively. In thumb opposition, transection of the DRL resulted in a mean increased 3-dimensional translation of 1.0 mm, whereas transection of the dAOL resulted in a mean increased 3-dimensional translation of 0.5 mm. CONCLUSIONS: In most degrees of freedom of metacarpal movement relative to the trapezium, the DRL is relatively more important than the dAOL in providing stability to the TMC joint.     

Osteoarthritis of the trapeziometacarpal joint: the pathophysiology of articular cartilage degeneration. II. Articular wear patterns in the osteoarthritic joint.

An anatomic and radiographic study of the osteoarthritic trapeziometacarpal joint was conducted on 27 surgical specimens harvested during basal joint arthroplasty. Surface wear patterns were analyzed by hyaline cartilage staining, and relative involvement of trapezium and metacarpal was calculated as the trapezium/metacarpal eburnation ratio. Eburnation occurred only on facing trapeziometacarpal surfaces in contact areas of the palmar compartment. Metacarpal degeneration began at the palmar joint margin adjacent to the beak ligament and extended dorsally, while trapezial degeneration originated on the central palmar slope and spread centrifugally with more advanced disease. Eburnation consistently involved a greater surface area on the trapezium than on the metacarpal in a ratio of nearly 3:1. A decreasing trapezium/metacarpal eburnation ratio correlated closely with worsening radiographic stage. These observations suggest translation of metacarpal on trapezium in the production of arthritic surface lesions and support a hypothesis of pathologic joint instability as the cause of trapeziometacarpal osteoarthritis.     

A quantitative method to measure maximal workspace of the trapeziometacarpal joint--normal model development.

INTRODUCTION: A reliable and quantitative method for measuring motion of the thumb is lacking. In particular, review of the previous methods of motion analysis of the thumb joints shows that there is no objective method for clinicians to assess the impairment of the thumb trapeziometacarpal (TMC) joint. Based on the concept of the three-dimensional (3-D) space within which the first metacarpal can move relative to the trapezium (a concept of defining and measuring the workspace of the TMC motion), we present a quantitative method for measuring motion and impairment (loss of function) of the TMC joint. METHODS: Twenty normal subjects were recruited in this study. An electromagnetic device was placed over the thumb metacarpal and long finger metacarpal, the 3-D relationship between them previously established. We measured the position and orientation of the TMC motion in space. Maximum movements of the thumb TMC joint in circumduction, flexion-extension and abduction-adduction were used to construct the 3-D maximal workspace of the TMC joint. Mathematical methods were used to verify the model and calculate the maximal workspace. RESULTS: The results of this study demonstrate accurate and repeatable measurement of 3-D TMC motion with high statistical reliability and low variability of the maximal TMC workspace. A statistically significant linear correlation between the maximal surface area and the square of the first metacarpal length was obtained. CONCLUSION: We conclude that a quantitatively comparative measurement of the range of motion of the TMC joint can be obtained with potential to measure motion in joints affected by arthritis or trauma and measured in both dynamic and static positions of the thumb.     

Surgical Treatment of Trapeziometacarpal Joint Arthritis: A Historical Perspective

Background

The trapeziometacarpal (TMC) joint’s unique anatomy and biomechanics render it susceptible to degeneration. For 60 years, treatment of the painful joint has been surgical when nonoperative modalities have failed. Dozens of different operations have been proposed, including total or subtotal resection of the trapezium or resection and implant arthroplasty. Proponents initially report high levels of patient satisfaction, but longer-term reports sometimes fail to support initial good results. To date, no one procedure has been shown to be superior to another.

Questions/purposes

This review sought to identify factors responsible for the development of many different procedures to treat the same pathology and factors influencing whether procedures remain in the armamentarium or are abandoned.

Methods

I performed a nonsystematic historical review of English-language surgical journals using the key words “carpometacarpal arthritis”, or “trapeziometacarpal arthritis”, and “surgery” in combination with “history” using the PubMed database. In addition, bibliographies of pertinent articles were reviewed.

Results

The factors that led to many surgical innovations appear to be primarily theoretical concerns about the shortcomings of previously described procedures, especially about proximal migration of the thumb metacarpal after trapezial resection. Longevity of a particular procedure seems to be related to simplicity of design, especially for prosthetic arthroplasty. The evolution of surgery for TMC joint arthritis both parallels and diverges from that in other joints. For example, for most degenerated joints (even many in the hand), treatment evolved from resection arthroplasty to implant arthroplasty. In contrast, for the TMC joint, the 60-year-old procedure of trapezial resection continues to be performed by a majority of surgeons; many modifications of that procedure have been offered, but none have shown better pain reduction or increased function over the original procedure. In parallel, many differently designed prosthetic total or hemijoint arthroplasties have been proposed and performed, again with as yet unconvincing evidence that this technology improves results over those obtained by simple resection arthroplasty.

Conclusions

Many procedures have been described to treat TMC joint arthritis, from simple trapezial resection to complex soft tissue arthroplasty to prosthetic arthroplasty. In the absence of evidence for the superiority of any one procedure, surgeons should consider using established procedures rather than adopting novel ones, though novel procedures can and should be tested in properly designed clinical trials. Tissue-engineered solutions are an important area of current research but have not yet reached the clinical trial stage.     

Sequential wear patterns of the articular cartilage of the thumb carpometacarpal joint in osteoarthritis

PURPOSE: The thumb carpometacarpal (CMC) joint is a primary location for osteoarthritis (OA) in the body; however, articular cartilage thickness distribution during progression of OA in the joint has not been reported previously. Determining the cartilage wear patterns within the joint is important in understanding the etiology and treatment of thumb CMC joint OA. This study used cadaveric specimens to investigate the wear patters of the articular surfaces of the trapezium and thumb metacarpal. METHODS: A total of 104 fresh-frozen thumb CMC joints were radiographed, disarticulated, and visually staged for OA. Cartilage thickness maps of the trapezium and metacarpal were determined for each joint by using stereophotogrammetry. Average cartilage thickness maps for the trapezium and metacarpal were generated from all specimens for each of 4 stages of OA, showing the progression of cartilage thickness changes with disease. RESULTS: In normal joints, the surface-wide mean thickness of the articular layers is 0.8 +/- 0.2 mm for the trapezium and 0.7 +/- 0.2 mm for the metacarpal. The average thickness maps were analyzed by anatomic quadrant (dorsal-radial, dorsal-ulnar, volar-radial, volar-ulnar) within the 4 stages of OA. Corresponding quadrants also were compared across the increasing stages of OA. Results show that cartilage degradation is initiated in the radial quadrants of the metacarpal and progresses to the volar quadrants of the articular surface, while significant wear is seen on the dorsal-radial quadrant of the trapezium and progresses to the volar quadrants in late-stage osteoarthritis. CONCLUSIONS: These quantitative results on cartilage thinning agree with previous investigators' reports of high load bearing and low load bearing areas in the CMC joint during functional pinch and grasp positions. Understanding the progression of OA in the thumb CMC joint may aid in the surgical treatment of this disease.     

The relation between primary osteoarthritis of the trapeziometacarpal joint and supernumerary slips of the abductor pollicis longus tendon

We have studied whether accessory abductor pollicis longus slips inserting into the thenar eminence or trapezium influence the incidence and severity of trapeziometacarpal joint osteoarthritis. The right first extensor compartment of 73 cadavers was dissected and trapeziometacarpal degeneration was graded macroscopically. The main abductor pollicis longus tendon which inserted at the metacarpal base was accompanied by supernumerary APL slips in 96% of cases. Thenar or trapezial slips occurred frequently but coexisted in only one case. The incidence of trapeziometacarpal arthritis was not influenced by the number of accessory slips or whether they inserted onto the thenar eminence or the trapezium.     

Trapezium implant arthroplasty: evaluation of a semiconstrained implant

Twenty-five patients who presented with symptoms of disabling pain secondary to arthritis at the base of thumb had 29 arthroplasties with silicone rubber trapezium implants. Stabilization was achieved with tenodesis using a strip of abductor pollicis longus as described by Eaton. All patients had relief of pain after surgery. We examined 23 hands in 19 patients for follow-up. Average follow-up was 31 months. Assessment of functional status and measurements of prehensile capabilities showed that all patients had improved after surgery. Range of motion of the thumb was measured (radial abduction averaged 40 degrees; 80% had full opposition). Average key pinch was 8 pounds. Stability of the implant was assessed with standard posteroanterior, lateral, and stress views of the trapeziometacarpal joint. Comparisons were made with previously reported results for Eaton and Swanson trapezium implants. The tenodesis effect may provide a more stable, although possibly less mobile, CMC joint of the thumb.     

Basal metacarpal osteotomy for osteoarthritis of the thumb

Thumb metacarpal extension osteotomy provides effective treatment for the hypermobile trapeziometacarpal joint consistent with Eaton stage 1 disease. This procedure is a useful alternative to Eaton ligament reconstruction. Clinical outcomes are favorable and, should symptoms persist, the procedure does not jeopardize satisfactory execution of trapezial resection arthroplasty in the future.     

Early osteoarthritis of the trapeziometacarpal joint is not associated with joint instability during typical isometric loading

The saddle‐shaped trapeziometacarpal (TMC) joint contributes importantly to the function of the human thumb. A balance between mobility and stability is essential in this joint, which experiences high loads and is prone to osteoarthritis (OA). Since instability is considered a risk factor for TMC OA, we assessed TMC joint instability during the execution of three isometric functional tasks (key pinch, jar grasp, and jar twist) in 76 patients with early TMC OA and 44 asymptomatic controls. Computed tomography images were acquired while subjects held their hands relaxed and while they applied 80% of their maximum effort for each task. Six degree‐of‐freedom rigid body kinematics of the metacarpal with respect to the trapezium from the unloaded to the loaded task positions were computed in terms of a TMC joint coordinate system. Joint instability was expressed as a function of the metacarpal translation and the applied force. We found that the TMC joint was more unstable during a key pinch task than during a jar grasp or a jar twist task. Sex, age, and early OA did not have an effect on TMC joint instability, suggesting that instability during these three tasks is not a predisposing factor in TMC OA. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1639–1645, 2015.     

Treatment of Eaton stage I trapeziometacarpal disease with thumb metacarpal extension osteotomy

The current benchmark for the treatment of Eaton stage I disease of the trapeziometacarpal (TMC) joint includes palmar oblique ligament reconstruction and reflects its primary role in providing stability during lateral pinch. This study prospectively evaluates the efficacy of an alternative extra-articular approach using a 30 degrees extension osteotomy of the thumb metacarpal to redistribute trapeziometacarpal contact area and load, obviating the need for ligament reconstruction. Preoperative and postoperative subjective and objective data are reported for 12 patients enrolled in the study between 1995 and 1998. Trapeziometacarpal arthrotomy allowed accurate intra-articular assessment and verified palmar oblique ligament incompetence in each case. The average follow-up period was 2.1 years (range, 6-46 months). All osteotomies healed at an average of 7 weeks. Eleven patients were satisfied with outcome. Grip and pinch strength increased an average of 8.5 and 3.0 kg, respectively. Thumb metacarpal extension osteotomy is an effective biomechanical alternative to ligament reconstruction in the treatment of Eaton stage I disease of the trapeziometacarpal joint.     

Reorientation osteotomy of the trapezial saddle

At its early stage, the thumb TM osteo-arthritis is occasionally painful during some activities and there are mainly radiological signs, only visible on specific views and with maximum amplitudes. They are the first metacarpal base imperfect reintegration in the trapezium saddle in ante-position and an increased slope angle of 140 degrees. So, the "slippery saddle" of the trapezium induces a metacarpal base subluxation. The goal of the proposed technique is to correct the orientation of the trapezial saddle. The slope angle must return to its normal value of about 125 degrees, thanks to an opening wedge osteotomy into the trapezium, completed with a bony wedge insertion. Proposed for the first time in 1983, and used only once by Dr. Heim, this technique was "rediscovered" recently and used on five patients in ten years. It is easy to do, the only complication being two post-operative radial nerve sensitive branch neuromas. In six cases on seven, the pain disappeared, even if the osteo-arthritis was evolving for the two former cases. The functional recovery was total and the patients were satisfied in most of the cases. In spite of this short series, this technique is worth being used for the early stage of thumb osteo-arthritis, eventually combined with others techniques like tenotomy of the Abductor pollicis longus accessories or different types of ligamentoplasties. It is, in any case, more logical than the first metacarpal osteotomy.     

Biomechanics of the trapeziometacarpal joint

The trapeziometacarpal joint is structured to allow simple angular and simultaneous angular or rotational movements of the first metacarpal. The geometry of the joint is partitioned as follows: a saddle-shaped area (the central area of the trapezium and metacarpal ridge), where simple angular movements occur, and a spherical region (the palmar area of the trapezial articular surface and metacarpal slopes), where simultaneous angular movements take place. Rotation of the first metacarpal during opposition (pronation) and retroposition (supination) depends on three factors: muscular activity, ligament tension, and congruence of the spherical portion of the trapeziometacarpal joint.     

Weilby tendon interposition arthroplasty for osteoarthritis of the trapezial joints

Primary osteoarthritis of the trapezial joints has been treated by an interposition tendoplasty according to Weilby in eighty-nine cases. After excision of the trapezium, a strip from the flexor carpi radialis was wound around the main portion of the flexor carpi radialis tendon and the abductor pollicis longus. The abductor tendon was then duplicated over the tendoplasty and reinserted to the first metacarpal base. In 40% of cases, osteoarthritis was present in more than one trapezial joint. 57% had an adduction contracture of the first metacarpal, half of which were relieved postoperatively. 73% of patients were satisfied at follow-up. Complications included four cases with loss of active metacarpal abduction which was regained after reinsertion of the abductor pollicis longus. It is concluded that the Weilby tendoplasty is a useful alternative to Silastic implants, especially in cases of adduction contracture. The risks of implant dislocation and silicone synovitis are eliminated.     

No correlation between trapeziometacarpal arthritis and abductor pollicis longus insertion

The primary hypothesis of this study is that supernumerary slips of the abductor pollicis longus (particularly those slips inserting distal to the trapeziometacarpal joint) increase the risk of trapeziometacarpal osteoarthritis on account of increased transarticular forces. Other hypotheses surmised that age and female gender were directly correlated with severity of arthritis. We did cadaveric dissection of the distal first dorsal compartment in 61 specimens, noting the cadaveric age, gender, and number and insertion sites of abductor pollicis longus tendon slips. Each variable was statistically correlated with visual grade of trapeziometacarpal arthritis. The median number of abductor pollicis longus tendon slips in these cadaveric hands was three (range, 1-4). Seventy-nine percent of the hands had a digastric-type insertion into the abductor pollicis brevis. Ninety percent had an insertion into the trapezium. All hands possessed an insertion into the base of the first metacarpal. Age and female gender were directly correlated with severity of arthritis. No other correlations existed. We conclude that trapeziometacarpal joint arthritis progresses with age and occurs independently of any aspect of abductor pollicis longus insertion. Based on our results, we do not recommend surgical release of these supernumerary abductor pollicis longus tendon slips for the treatment of trapeziometacarpal osteoarthritis.