Index Metacarpophalangeal Joint Research Articles

Analysis of Intrinsic–Extrinsic Muscle Function Through Interactive 3-Dimensional Kinematic Simulation and Cadaver Studies

To revisit the analysis of intrinsic muscle function and its relationship to the overall flexion moment at the index metacarpophalangeal (MCP) joint. Prior studies reported inconsistent levels of intrinsic contribution varying from 12.5% to 73% of the total flexion moment at the index MCP joint. This study hypothesized that 26% is a more realistic figure using computer simulation moment arms combined with known muscle-tension fractions. This study tested the hypothesis using a 2-part fresh cadaver study, the objectives of which were to measure actual muscle moment arms throughout index MCP range of motion and then combine these measurements with tension fractions to calculate normal intrinsic minus and low ulnar nerve palsy moments and then using the same specimens to apply loads to the muscles and measure resultant moments directly. An interactive computer simulation was constructed to replicate the position and loading orientation of an earlier experiment reported in the literature and known muscle-tension fractions were combined with the resultant moment arm structure to calculate the moment at the index MCP joint for maximum isometric contraction of the normal, intrinsic minus, and low ulnar nerve palsy finger. Eleven fresh cadaver specimens were used. For experiment A the excursion and angle data were used to determine moment arms of each muscle and moments were calculated. For experiment B the muscles were connected to weights based on muscle-tension fractions and the resultant moment was measured at the fingertip. Experiment A determined the muscle-tendon moment arms at the index MCP joint throughout the flexion-extension range of motion. Combining the flexor moment arms with known tension fractions determined that the intrinsics contributed 24% to the total flexion moment, the dorsal and palmar interossei contributed 22%, and the lumbrical contributed 2%. The results of experiment B confirmed the results of experiment A. Intrinsic muscle contribution to flexion moment at the index MCP joint is not as high or as low as previously reported. The relative moment production is governed by both the moment arms and tension produced by the muscle; thus a more precise knowledge of moment arms is essential to understand muscle balance at a joint. Clinically the hand surgeon should expect a loss of 24% of index MCP flexion moment-generating capacity in the intrinsic-minus index finger and a loss of 22% in the index finger on a hand with low ulnar nerve palsy. Furthermore the flexion moment from the lumbrical of only 2% appears to be adequate to prevent clinical clawing of the digit.

Osteochondral metatarsophalangeal autografts for traumatic articular metacarpophalangeal defects: A preliminary report

Five consecutive patients with saw injuries to the dorsal portion of the index metacarpophalangeal joint and resultant partial osteochondral defects underwent articular reconstruction using contoured metatarsophalangeal osteochondral autografts. At an average follow-up period of 33 months, all patients achieved full metacarpophalangeal extension, with 74° of flexion and grip strength equal to 86% of the contralateral hand. Discomfort was minimal, with crepitus present in one patient. X-ray films revealed joint space narrowing or articular step-off of 1 mm or less.

Bilateral sacroiliac fracture-dislocation

A 16-year-old presented to the accident and emergency department, having crushed his left great toe with a heavy cannon ball. External appearance was typical of a crushed toe with swelling, tenderness and bruising. Passive movements of the interphalangeal joint were very painful. Radiographs of the great toe showed an accessory sesamoid bone dislocated into the interphalangeal joint (Figure I). Radiographs of the opposite toe revealed a similar accessory bone at the head of the proximal phalanx of the great toe (Figure 2). Under ring block, manipulation was undertaken by holding the toe at the base and manipulating the distal phalanx. Closed reduction was successful, and radiographs after manipulation showed satisfactory reduction of the interphalangeal joint (Figure 3). A boot plaster was applied for 3 weeks. Recovery was uneventful. Intra-articular sesamoid dislocation is a rare injury and may lead to difficulty in reduction and diagnosis. Sesamoid injuries have been reported in the index metacarpophalangeal joint (Sweterlitsch et al., 1969) and in the first metatarsophalangeal joint (Deluca and Kenmore, 1975), both of which needed open reduction. Diagnosis in adolescents may cause problems, as it could be mistaken for an epiphyseal injury (Figure I). The interphalangeal sesamoid of the hallux is only present in approximately 13 per cent of the population (Burrnan and Lapidus, 1931; Jahss, 1981). Bamett et al. (1979) reported a similar case, but their efforts at closed manipulation were unsuccessful and open reduction was very difficult, necessitating excision of the sesamoid. Dislocation of a sesamoid bone into the interphalangeal joint of a great toe without fracture is unusual. Although surgery may be required for these cases, we would recommend closed reduction in the first instance.

Complex dislocation of the metacarpo-phalangeal joint of the index finger: A comparison of the surgical approaches

Complex dislocation of the index metacarpo-phalangeal joint almost always requires surgical intervention. Controversy exists as to the most suitable surgical approach to reduction: palmar or dorsal. We reviewed four cases and carried out dissections in eight cadaver hands to compare the surgical approaches. The interposed volar plate was found to be the most important obstacle to reduction. Both approaches were successful in obtaining reduction. The dorsal approach was simple and safe, but necessitated longitudinal division of the volar plate and may carry a theoretical risk of late instability. The palmar approach allows restoration of normal anatomy but the radial neurovascular bundle is always vulnerable.

Kinematics and stabilizing roles of capsuloligamentous structures in index metacarpophalangeal joint

s 369 KINEMATICS AND STABILIZING ROLES OF CAPSULOLICAMESTOUS STRUCTURES 1s ISDEX METACARPOPHALAN’GEAL JOIST AKIO MINAW. KAI-NAN As, WILLIAM P. COOKEY III. ROS.ALD L. LINSCHEID and EDMUND Y. S. CHAO. Gross examination of the metacarpophalangeal collateral ligaments of human cadaver specimens demonstrated that the ligaments were separated into two layers, one superficial and the other deep. The distances between origin and insertion of the collateral ligaments were measured with biplanar radiographic technique throughout the range of joint flexion. Dorsal and volar portions of both collateral ligaments were found to be under tension in flexed and extended positions, respectively. The relative contribution of the collateral ligaments to joint stability was studied by using stiffness tests on an MTS machine. The results of sequential sectioning of the ligaments indicate that the radial collateral ligament contributed to constraint of pronation and adduction, while the ulnar collateral ligament mainly contributed to constraint of supination and abduction. The volar plate was important in preventing dorsal displacement, while the dorsal capsule was found generally insignificant. MATHEMATICAL MODEL OF THE HIP CAPSULE IN CONGENITAL HIP DISEASE GEORGE T. RAB (Department of Orthopaedic Surgery, Universi!y of California, Davis, CA, U.S.A.) A three-dimensional mathematical model of the hip capsule in bony structures has been devised to allow study of the elfect of femoral position on capsular tightness in intra-articular stability. The model has been used to investigate factors in stability of congenitally dislocated hips. Common positions clinically in use for immobilization of the hip are successful because they twist the capsule, eliminating redundancy. Clinically observed persistent instability after capsulotomy is quantitated and confirmed. The capsule is also found to be important in procedures which have been generally thought of as bony; namely, Salter osteotomy and varus derotation osteotomy. AN ANALYTICAL STEREOPHOTOGRAMMETRIC METHOD TO iMEASURE THE THREEDIMENSIONAL GEOMETRY OF ARTICULAR SLRFACES R. HUISKES and A. DE LANGE (Biomechanics Section, Laboratory of Experimental Orthopaedics, University of Nijmcgen, 6500 HB, The Netherlands) Accurate description of the three-dimensional geometry of articular surfaces in skeletal joints have become essential information in several kinds of biomechanical investigations. To measure these data a technique was deveioped, based on analytical stereophotogrammetry, which, as compared to other methods reported, is believed to be a good cost-efficient compromise between accuracy and simplicity. Tests were performed on known curved surfaces,and a total accuracy (95 % confidence interval) between about 0. I and I.5 mm in the threedimensional position of a surface point was found to be possible, depending on the equipment and conditions chosen. This method was applied to measure the geometry of knee-joint surfaces and to evaluate the locationdependent thickness of the cartilage. COMPUTER MODELLING OF PROXIMAL FEMUR OSTEOTOMIES D. R. PEDERSEN and R. A. BRAND (Orthopaedic Biomechanics Laboratory, University of Iowa Hospitals and Clinics, Iowa City, IA, U.S.A.) We have developed techniques to predict mechanical effects of musculo-skeletal operations on joint loads and muscle force distribution. Biological effects are not addressed. This study investigates 10, 20 and 30’ intertrochanteric varus-valgus osteotomies and ante-retroversion rotations of the proximal femur. Assuming surgical intervention is to help the patient achieve a normal gait pattern, these anatomic changes were introduced into our gait analysis model with normal data. While littleeffect was seen on peak hip, knee and patello-femoral resultants, the femoral head experienced 59 % to 1707; of normal anterior force in the 30’ retro-anteversion simulations. Anteversion of 30’ caused 19% and 10 TtA increases in the gluteus minimus and medius and a 22 y0 decrease from normal in the gluteus maximus. Thirty degree retroversion elicited 21%. 20% and 60 % increases in these same three muscles. The rectus femoris and tensor fascia latae experienced a 33 % increase after 30” anteversion and a 33 % decrease after femoral retroversion. These muscles remained within 10% of normal after varus-valgus displacement, except the gluteus minimus at 150% of physiologic in 30’ valgus.

Perichondrial arthroplasty in the hand: A case report

A two-stage arthroplasty technique was used to treat an isolated fibrous ankylosis that developed in the index metacarpophalangeal joint of a 14-year-old boy after a rattlesnake bite. The first stage consisted of a minimal joint resection combined with rib perichondrial grafts to resurface the joint. The second stage, performed 5 months later, consisted of a capsulotomy and removal of a silicone membrane left within the joint to separate the grafts. Biopsy of the joint surfaces revealed the presence of hyaline-like cartilage. Nearly normal pain-free motion was restored. Follow-up now exceeds 30 months.

Clear view of the index sesamoid: A sign of irreducible metacarpophalangeal joint dislocation

If the index sesamoid bone is clearly seen in the joint following significant injury to the index metacarpophalangeal joint on radiographic examination, there is the probability of incarceration of the volar plate. In almost all cases, an open reduction will be necessary to re-establish the normal relationship between the second metacarpal and the proximal phalanx. In a case of irreducible dislocation of the index metacarpophalangeal joint, attempted reduction caused the injury to appear as a subluxation.

A simplified technique for treating the complex dislocation of the index metacarpophalangeal joint

The volar approach to open reduction of the complex dislocation of the index metacarpophalangeal joint as described by Kaplan proved to have certain disadvantages. Digital nerves are easily damaged during exposure and there is a limited view of the entrapped fibrocartilaginous volar plate dorsal to the metarcarpal head. A direct dorsal longitudinal incision through the skin and extensor tendon gives full exposure. The volar plate attached to the proximal phalanx and trapped over the dorsal aspect of the metacarpal head is in full view. The volar plate is split longitudinally and the dislocation reduces spontaneously as the flexor tendons and lumbrical muscle slip by the metacarpal head. The advantages of this approach as compared with the volar approach are: (1) there is full exposure of the fibrocartilaginous volar plate, the main structure blocking reduction; (2) digital nerves are not as apt to be damaged; and (3) accurate reduction and fixation of the osteochondral fracture of the metacarpal head, frequently seen with this dislocation, is possible.

Entrapment of a Sesamoid in the Index Metacarpophalangeal Joint

Entrapment of a Sesamoid in the Index Metacarpophalangeal Joint

Dorsal Dislocation of the Metacarpophalangeal Joint of the Index Finger with Particular Reference to Open Dislocation

1. Nine cases of dorsal dislocation of the index metacarpophalangeal joint are reported. 2. Three open dorsal dislocations of the index metacarpophalangeal joint are reported and discussed. 3. Six closed dorsal dislocations of the index metacarpophalangeal joint were treated by manipulation which failed to reduce the dislocation. In all six open reduction was necessary.