Molecular cloning in Arabidopsis thaliana of a new protein phosphatase 2C (PP2C) with homology to ABI1 and ABI2

Trapeziectomy, ligament reconstruction and tendon interposition arthroplasty is one of the most commonly performed procedures to address pain and instability due to osteoarthritis at the basal joint of the thumb. To determine the effect of stress on first metacarpal subsidence, 15 ligament reconstruction and tendon interposition basal joint arthroplasties were evaluated after a mean follow-up of 32 months. Radiographs were obtained of the arthroplasty at rest and then with maximal effort key pinch stress, which is known to subject the first carpometacarpal joint to considerable axial compression stress. Compared with the preoperative x-rays, the first metacarpal had subsided 21% of the arthroplasty space at rest. Under stress, the first metacarpal was found to subside another 10.5% in height. No subluxation of the metacarpal base could be detected. Key pinch strength improved 17% from the preoperative strength. Tip-to-tip pinch strength improved 17% from the preoperative measurement. Grip strength improved 17% from the preoperative measurement. Grip strength was 9% greater than the preoperative grip strength. There was no statistical association between the amount of first metacarpal subsidence and follow-up key pinch, tip pinch, or grip strength. With axial compressive loading of the arthroplasty, such as in lateral pinch, there is some further proximal migration of the first metacarpal, but this is minimal and does not correlate with functional outcome.     

Variations in thickness of articular cartilage in the human sacroiliac joint

Differences in articular cartilage thickness in the sacroiliac joint were investigated in different regions of the sacral and the iliac articular surfaces in the embalmed cadavers of five males and six females. The mean thickness of the sacral articular cartilage was greater than that of the iliac articular cartilage (P < 0.001) and the sacral articular cartilage of the female was thicker than that of the male (P < 0.02). Differences between thicknesses of the iliac articular cartilage in the male and female and in different regions of the sacral and iliac articular cartilages were found to be not significant.     

Carpometacarpal arthritis of the thumb

Forty-five flexor carpi radialis (FCR) tendon interposition arthroplasties of the trapezium for the treatment of carpometacarpal osteoarthritis were reviewed. The average follow-up period was 103 months (range, 22-213 months). Pain was reduced in 42 (93%) of the cases. Mobility was equal to that of the unoperated side. Key pinch and grip strengths compared to the unoperated thumb measured 86% and 90%, respectively. The mean distance between the scaphoid and the base of the first metacarpal bone was 7 mm (range, 2-12 mm). Function was improved in 39 (87%) of the cases, and in 42 (93%) of the cases the overall results were satisfactory. The results of this study show that FCR tendon interposition arthroplasty gives satisfactory long-term results.     

Flexor carpi radialis tendinitis. Part I: Operative anatomy

The anatomical characteristics of the flexor carpi radialis tendon, the tendon sheath, the tunnel boundaries, and the adjacent structures were examined in twenty-five adult cadaveric specimens. Transverse and sagittal sections of the wrist and forearm, tenograms, and histological sections of the tendon were made from two additional specimens each. The musculotendinous portion of the flexor carpi radialis tendon begins an average of fifteen centimeters (range, twelve to seventeen centimeters) proximal to the radiocarpal joint; the muscular fibers end an average of eight centimeters (range, six to nine centimeters) proximal to the wrist. The synovial sheath extends from the origin to the insertion. The tendon enters a fibro-osseous tunnel at the proximal border of the trapezium and is separated from the carpal canal by a thick septum that functions, at its distal border, as a pivot point for the flexor pollicis longus. Within the tunnel, the tendon occupies 90 per cent of the available space and is in direct contact with the slightly roughened surface of the trapezium. The tendon lies within a few millimeters of the distal aspect of the radius, the scaphoid tubercle, the scaphoid-trapezium-trapezoid joint, and the carpometacarpal joint of the thumb. In most patients, the flexor carpi radialis tendon is inserted at three locations. A small slip is connected to the trapezial crest or tuberosity; 80 per cent of the remaining tendon is inserted on the base of the second metacarpal and 20 per cent, on the base of the third metacarpal. The deep palmar arch is located two to three millimeters distal to the insertion of the tendon.     

Morphogenesis of the epithelial cell transporting phenotype: synthesis and distribution of ion channels

Open partial trapeziectomy and interpositional arthroplasty have proven to be effective in ameliorating the symptoms of carpometacarpal joint arthritis of the thumb. Surgical technique of arthroscopic partial resection of the trapezium and interpositional arthroplasty is described. Thirty-three interpositional arthroplasties were carried out arthroscopically. Autogenous tendon graft. Gortex (WL Gore & Associates, Inc. Flagstaff, AZ) and fascia lata allograft were used as interpositional material; 87.8% of patients got relief from pain. Average postoperative pinch strength was 11 lbs. No ligament reconstruction was required because the capsule was left intact. The procedures were done on an outpatient basis and all patients were discharged the same day. There were no complications associated with radial sensory nerve.     

Stabilization of silastic implant arthroplasty at the trapezometacarpal joint

Instability of the carpometacarpal joint of the thumb may accompany silastic implant arthroplasty. A collapse deformity of the thumb with resultant loss of pinch power impairs hand function. A procedure is described, which allows apical stabilization of the base of the thumb. Compressive forces may then act on the thumb to produce divergence in abduction without collapse instability and yet allow enough motion for convergence in oposition and restoration of asymptomatic three-point pinch.     

The effects of training specific mnemonics on the metamnemonic efficiency of retarded children

On examination of the thumbs of 20 dissected preparations of ligaments and joints, of ten dry skeletons and of a number of living hands, apoposition (from apo = away from) was distinguished as a position in which the first carpometacarpal joint is fully abducted and laterally rotated and in which one or both distal joints of the thumb are flexed. Apoposition is commonly used in writing and it has a specific osteoligamentous basis for its stability: (1) a Y-shaped intermetacarpal ligament is attached by two crura to the base of the second metacarpal bone and by a common stem to the first metacarpal. Together with the palmar and dorsal oblique ligaments it becomes taut at abduction and establishes thereby a fixed center for the circumduction. Stability is enhanced as the circumduction takes place in the radial flat part of the joint away from the center; (2) of the two palmar prominences of the head of the first metacarpal bone the radial is the larger. At 25-30 degrees flexion in the metacarpophalangeal joint the prominence fits into an excavation on the base of the proximal phalanx in a manner which together with the ulnar collateral ligament locks the joint against mutual abduction and lateral rotation, and (3) the radial part of the trochlea of the interphalangeal joint is larger than the ulnar and secures, together with the ulnar collateral ligament, the joint against a radial luxation. Apoposition does not require activity of the thumb muscles; it is brought about by applying an external force to the ulnar side of the thumb and it is checked by ligaments and the shape of the joints.     

Tibiofemoral contact pressures in degenerative joint disease

Using tibiofemoral joints from older (age, 53-80 years) human cadavers with articular cartilage degeneration, contact pressures and contact areas were measured in the extended knee in four conditions: (1) neutral alignment; (2) 5 degrees varus (simulating single limb stance of gait); (3) 5 degrees valgus; and (4) after a 5 degrees proximal tibial closing wedge valgus osteotomy. In degenerated cartilage, contact pressures were reduced at the lesion sites and were high on the borders of the lesions. No statistically significant changes occurred in contact pressures and areas when values from neutral loading were compared with values during loading in each of the other three conditions. Lateral average and maximum contact pressures were less in varus loading than in valgus loading. Equal medial and lateral contact pressures during varus loading, in contrast to lower medial than lateral contact pressures in the other three loading, supports the theory that the varus moment imposed on the knee in single limb stance could be a mechanism causing medial tibiofemoral osteoarthritis. The 5 degrees valgus osteotomy resulted in contact pressures similar to those in neutral loading. These experiments do not support the value of the 5 degrees valgus osteotomy in reducing contact pressures on the medial tibial plateau.     

Electrocardiographically gated myocardial perfusion SPECT: technical principles and quality control considerations

BACKGROUND: Apoptosis in vivo has been identified in developing cartilage from embryonic chick sterna and avian and murine growth plates. To date, no evidence exists that chondrocytes in articular cartilage undergo apoptosis. METHODS: We examined the distribution of cells demonstrating fragmented DNA in the articular knee cartilage of C57BL/6 mice (aged 11, 18, 24, and 30 months) and Wistar rats (aged 6, 12, and 24 months) using a DNA end-labeling technique. RESULTS: Control experiments utilizing retinoic acid-induced apoptosis in a chondrocyte cell line, established that DNA end-labeling correlated with DNA ladder formation. In vivo, apoptotic cells were detected in articular cartilage tissue in both species examined. The percentage of apoptotic cells increased significantly (P < 0.05 with age) for all joint surfaces in both species. No significant difference was found between the medial and lateral or femoral and tibial joint surfaces of the knee. Apoptotic cells were observed in both the calcified and uncalcified regions of the articular cartilage of C57 mice. In the rat, only the calcified region of articular cartilage contained apoptotic cells. CONCLUSIONS: These results suggest that apoptosis plays a role in some aspect of maintenance, remodeling, or turnover of mature articular cartilage. In addition, the increase in apoptosis associated with aging could contribute to the greater risk for cartilage degeneration.     

Observations on the joints of the hand

Thirty-two hands (sixty-eighty years) were dissected to study configuration and spatial setting of the articular surfaces of the joints of the thumb in order to note the features which are associated with deviation, torsion and rotatory movements. Four varieties of the trapezial surface were encountered in the carpometacarpal joint: saddle-shaped, triangular, ovoid and semicylindrical. The last exhibited marked osteoarthrosis with formation of osteophytes.     

Necropsy survey of metacarpal fusion in the horse

Paired metacarpi obtained at necropsy from 100 horses ranging in age from term fetus to 35 years were examined to estimate the prevalence and sites of metacarpal fusion. Metacarpal fusion was seen in 192 of 200 metacarpi, and 78% of all horses 2 years or older had 2 or more fusions. Fusion of the second metacarpal bone to the third metacarpal bone was significantly (P < 0.001) more common than was fusion of the fourth to the third metacarpal bone. Fusions appeared for the most part in pairs and were bilaterally symmetric. Rooney-Prickett type-A carpometacarpal joint configurations (in which there is no measurable articulation between the third carpal and second metacarpal bones) were rare in this population, and Rooney-Prickett type-B configurations (in which there is a measurable articulation between the third carpal and second metacarpal bones) were observed in 98.5% of metacarpi. Medial metacarpal fusion was positively correlated with age, occupation, and proportion of the proximal projection of the carpometacarpal distal joint surface that was taken by the second metacarpal bone. Lateral metacarpal fusion was positively correlated with age and the proportion of the proximal projection of the carpometacarpal distal joint surface taken by the fourth metacarpal bone. Horses in performance careers (racing, race training, or show ring occupations) had an earlier development of the first 2 fusions than did horses in other or unknown occupations; development of the third and fourth fusions were not significantly different between occupation groups. The rate of metacarpal fusion per horse-year appeared to be at least 10 times higher than a clinically evident rate. A variety of gross morphologic features was observed in the fusions from this sample, some of which were small, subtle, and possibly difficult to detect in vivo. It is hypothesized that many instances of metacarpal fusion may be a result of functional adaptation of the metacarpus to increased or changed loading conditions, rather than a response to isolated traumatic events.     

Locomotor adaptations reflected in the wrist joints of early tertiary primates (adapiformes)

The positional behaviors inferred for early Tertiary adapiform primates have been the subject of considerable debate. Adapiform wrist morphology is analyzed here within the context of extant morphoclines in carpal joint shape in order to reconstruct adapiform positional behavior. Extant vertical clingers, slow climbers, and arboreal quadrupeds differ significantly from one another in length of the m flexor carpi ulnaris lever arm, shape of the midcarpal joint articular surface, and size and divergence of the pollical carpometacarpal articulation. These morphological differences are functionally related to differential requirements for wrist flexion, midcarpal mobility and stability, and pollical grasping, respectively. Adapis, Notharctus, and Smilodectes share with living arboreal quadrupeds a tall pisiform body, a mediolaterally flat midcarpal joint surface, and a relatively unexpanded thumb joint. Functionally, these features are related to flexing the wrist from extended positions during palmigrade, quadrupedal locomotion, increasing midcarpal joint stability during quadrupedal, weight-bearing postures, and grasping arboreal supports of predominantly horizontal and oblique orientation. The Messel adapiform (genus indet.) shares certain features of the midcarpal and pollical carpometacarpal articulations with extant vertical clingers, suggesting that this taxon used vertical substrates more frequently than other adapiforms.     

Simple excision of the trapezium for osteoarthritis of the carpometacarpal joint of the thumb

We have reviewed the results in 34 patients (39 operations) following simple excision of the trapezium for osteoarthritis of the basal joint of the thumb. The average age at operation was 57 years and the average follow-up was 6 years. All the patients were graded clinically and radiologically and were asked their opinion of the procedure. There was dramatic relief of pain following this procedure. Stability of the thumb was not compromised. When compared to the unoperated side, thumb length, thumb abduction and first web span were similar. There was a reduction in pinch strength (operated 8.1 k.p.a., non-operated 9.6 k.p.a.) and grip strength (operated 15.5 k.p.a., non-operated 19.5 k.p.a.) and an increase in MIP extension (operated 5.4 degrees, non-operated 2.9 degrees) following this procedure but the differences were not statistically significant. 11 patients (32%) had scar hyperaesthesia on testing but this was a clinical problem in two patients only (5%). Simple excision of the trapezium is a satisfactory procedure for the majority of patients with this disorder, but has a long post-operative rehabilitation period.     

Trapeziectomy and ligament reconstruction for osteoarthrosis of the base of the thumb. A prospective study of 100 operations

100 thumbs with primary osteoarthrosis of the joints of the trapezium were treated by trapeziectomy and a FCR sling arthroplasty to reconstruct a first intermetacarpal ligament by the method described by Burton and Pellegrini (1986). Pain at rest remained in five. Some pain at or after exertion persisted in 46, and 49 became completely pain-free. 88 were satisfied with the procedure and there was a significant increase in pinch strength and in the ability to perform activities of daily life. It has become our preferred procedure for treating osteoarthrosis of the basal joint of the thumb.     

New concepts in arthroplasty of the hand and wrist

Clinical trials with cemented polyethyiene and metal total joint arthroplasties were initiated in 1973. Replacements have been developed for the wrist, carpometacarpal joint of the thumb, metacarpophalangeal joints of the thumb and fingers, and the proximal interphalangeal joints of the fingers. Results, evaluated by pain relief and joint stability, were excellent at all sites. Motion, however, averaged only 50% of normal. Significant problems included abnormal posture in the wrist, roentgenographic evidence of loosening in the finger metacarpophalangeals, extensor lag in the metacarpophalangeal of the thumb, and lack of motion in the proximal interphalangeal joint of the finger.     

Osteoarthritis at the base of the thumb. The concept of monoarticular reconstruction

Osteoarthritic affection of the base of the thumb involving 148 hands has been studied. Isolated osteoarthritis of the trapezio-metacarpal joint was found to be the largest group including a total of 111 hands. Reconstruction of this particular joint by a new technique is described and long-term results reported. A small series of isolated osteoarthritis of the trapezio-scaphoid joint is presented and reconstruction by replacing the affected articular surface of the carpal scaphoid is described. Osteoarthritic involvement of more than one of the articular surfaces of the trapezium was found in a group of 31 hands. In all of them the trapezio-metacarpal joint was predominantly affected. The rationale for monoarticular reconstruction of the trapezio-metacarpal joint, regardless of the extent of involvement, is discussed in detail.     

The morphology of synovial grooves (Fossae synoviales) in joints of cattle of different age groups

The joint cartilage of the head of the radius, the metacarpal bone, the tibial cochlea, the proximal trochlea of the talus and the metatarsal bone of 26 cattle in the age groups fetuses, 0 days, 2-5 weeks, 2-5 months, 7-13 months, 2-3.5 years, and 5-7 years were examined macroscopically and histologically. Synovial grooves developed on all joint surfaces examined, but at different times. At some locations the development of the grooves began prenatally. During the groove development the same features were in principle observed on all joint surfaces: Degeneration and progressive thinning of the joint cartilage, invasion of connective tissue into the cartilage, cessation of the endochondral ossification, and depression of the groove area into the subchondral bone. The findings indicated that the synovial grooves should be considered as being part of the normal morphology of the joints. In 4 animals aged from 3 weeks to 13 months dyschondroplastic (osteochondrotic) lesions were observed in the joint cartilage both inside and outside the groove areas on one or more joint surfaces.     

Quantitative analysis of incongruity, contact areas and cartilage thickness in the human hip joint

Joint incongruity and cartilage thickness have been shown to determine the contact stresses and the load partitioning between the solid and fluid phases of articular cartilage. Matrix stresses, which are relevant in the development of osteoarthrosis, can, however, not be determined experimentally but must be calculated using numerical methods. The aim of the present study was to quantify the incongruity and cartilage thickness of the human hip, in order to allow for the construction of morphologically accurate finite element models. Twelve cadaveric specimens (34-86 years), two fresh and ten fixed, were investigated. The loading configuration was based on in vivo measurements of hip joint forces during midstance. The incongruity and contact areas were determined using a polyether casting technique, in the minimally and the fully loaded state. The cartilage thickness was measured at identical coordinate points with an A-mode ultrasonic system. Generally, the contact started at lower loads at the edge of the lunate surface, and the joint space increased towards its central aspects. In some specimens the contact started in the acetabular roof, leaving a joint space of up to 2 mm in the horns of the lunate surface. In others, the initial contact was observed in the anterior and posterior horns of the lunate surface with a joint space width of up to 0.75 mm in the acetabular roof. The size of the contact areas increased from about 20% of the lunate surface to 98% at higher loads. The articular cartilage thickness ranged from 0.7 to 3.6 mm, the maxima being located in the ventral aspects of the femoral head and acetabulum. These quantitative data on joint space width, contact, and cartilage thickness in the human hip joint may be used to construct and validate finite element models which are required to elucidate the mechanical factors involved in osteoarthrosis.     

Biomechanical topography of human articular cartilage in the first metatarsophalangeal joint

The objective of this study was to provide a map of cartilage biomechanical properties, thickness, and histomorphometric characteristics in the human, cadaveric first metatarsophangeal joint, to determine if normal articular cartilage was predisposed topographically to biomechanical mismatches in articulating surfaces. Cartilage intrinsic material properties and thickness were obtained from seven pairs of human, freshly frozen, cadaveric, metatarsophalangeal joints using an automated creep indentation apparatus under conditions of biphasic creep. Eight sites were tested: four on the metatarsal head, two on the proximal phalanx base, and one on each sesamoid bone to obtain the aggregate modulus, Poisson's ratio, permeability, shear modulus, and thickness. Cartilage in the lateral phalanx site of the left metatarsal head had the largest aggregate modulus (1.34 MPa), whereas the softest tissue was found in the right medial sesamoid (0.63 MPa). The medial phalanx region of the right joint was the most permeable (4.56 x 10(-15) meter4/Newton-second), whereas the medial sesamoid articulation of the metatarsal head of the left joint was the least permeable (1.26 x 10(-15) meter4/Newton-second). Material properties and thickness are indicative of the tissue's functional environment. The lack of mismatches in cartilage biomechanical properties of the articulating surfaces found in this study may be supportive of clinical observations that early degenerative changes, in the absence of traumatic events, do not occur at the selected test sites in the human first metatarsophalangeal joint.     

Composite finger metacarpophalangeal joint reconstruction in combined second and third free toe-to-hand transfers

Composite metacarpophalangeal joint reconstruction using the toe proximal phalanx and the metacarpal head, with a capsular repair, is an option during free toe transfer procedures for absent fingers. Eleven composite metacarpophalangeal finger joint reconstructions were performed in four patients concurrent with combined second and third toe-to-hand transfer. The average follow-up period was 5 years. Postoperative assessment included range of motion, stability, radiographic changes, and pain. The average range of motion was 52 degrees, average ulnar stress deviation was 14 degrees. No patients complained of pain. Composite metacarpophalangeal joint reconstruction should be considered in free toe-to-hand procedures when metacarpal head articular cartilage is preserved.