Thumb Interphalangeal Joint Research Articles

REPRODUCIBILITY OF MEASUREMENTS OF THUMB ABDUCTION

The reproducibilities of various measurements of thumb abduction were compared. Two independent observers measured the thumb abduction in 30 volunteers by the following four methods: distance between the thumb tip and the flexion crease of the index finger proximal interphalangeal joint; distance between the flexion crease of the thumb interphalangeal joint and the proximal palmar crease; angle between the thumb and index metacarpals; and angle between the thumb and index proximal phalanx. Measurements were repeated in three weeks and their reproducibility was assessed by the intraclass correlation coefficient (ICC). Intra-observer reproducibilities by distances were high with ICCs between 0.74 and 0.89, compared with those by angles with ICCs between 0.28 and 0.71. Inter-observer reproducibilities by distances were also high (ICCs = 0.79 and 0.81) compared with those by angles (ICCs = 0.28 and 0.42). Assessment of thumb abduction based on distance in the first web is recommended in terms of reproducibility.

Limited open reduction and internal fixation combined with mini external fixator to intra-articular fracture of the hand.

Objective To investigate the method and clinical outcome of limited open reduction and internal fixation combined with mini external fixator to intra-artieular fracture of the hand. Methods From May 2002 to May 2007, twenty-six patients (21 males and 5 females) with intra-articular fracture of the hand were treated. Metaearpophalangeal joint was involved in 11 cases, proximal interphalangeal joint was in-volved in 13, and interphalangeal joint of thumb in 2. The patients aged from 12 to 52 years, averaged 25.5 years. Concomitant bone injury included metacarpal fracture in 3 eases, and seaphoid fracture in 1. Orthofix mini external fixator was used in all cases, and Kirschner wire, mini wire and absorbable suture were used for internal fixation. Concomitant fracture should be treated simultaneously with shape memory alloy,Kirsehner wire, or plate-screw system. Results The patients were followed up for 6-30 months,averaged 11.5 months. X-ray identified fracture union in all cases, and the average union time was 7 weeks ranging 5-12 weeks. Phalange shortening or rotation was noted in 2 eases, joint incongruity (less than 1 mm) and jointspace narrowing in 3 respectively. A proximal interphalangeal joint replacement was performed in one case with traumatic arthritis 1.5 years after surgery. 17 patients returned to their original living styles and occu-pations. ATM standard was used to evaluate the motion function of the injured fingers, which comprised of 8 excellent results, 13 good results, 3 fair results and 2 poor results. The overall good-excellent rate of joint motion function was 81%. No instability occurred in all joints at the follow-up. Conclusion Limited open reduction and internal fixation combined with mini external fixator is a reliable and effective method for in-tra-artieular fracture of the hand, and elinieal outcome is promising. Major problems, such as bone shorten-ing, rotation deformity and joint space narrowing, still exist. Key words: Fractures; Hand; External fixators; Fractures fixation, internal

Radiographic hand osteoarthritis: patterns and associations with hand pain and function in a community-dwelling sample

Patterns of radiographic osteoarthritis (ROA) of the hand are often examined by row, with the four joints of the thumb studied inconsistently. The objectives of this study were to determine relationships of ROA at different hand joints, use the findings to define radiographic sub-groups and investigate their associations with pain and function. Sixteen joints in each hand were scored for the presence of ROA in a community-dwelling cohort of adults, 50-years-and-over, with self-reported hand pain or problems. Principal components analysis (PCA) with varimax rotation was used to study patterns of ROA in the hand joints and identify distinct sub-groups. Differences in pain and function between these sub-groups were assessed using Australian/Canadian Osteoarthritis Index (AUSCAN), Grip Ability Test (GAT) and grip and pinch strength. PCA was undertaken on data from 592 participants and identified four components: distal interphalangeal joints (DIPs), proximal interphalangeal joints (PIPs), metacarpophalangeal joints (MCPs), thumb joints. However, the left thumb interphalangeal (IP) joint cross-loaded with the PIP and thumb groups. On this basis, participants were categorised into four radiographic sub-groups: no osteoarthritis (OA), finger only OA, thumb only OA and combined thumb and finger OA. Statistically significant differences were found between the sub-groups for AUSCAN function, and in women alone for grip and pinch strength. Participants with combined thumb and finger OA had the worst scores. Individual thumb joints can be clustered together as a joint group in ROA. Four radiographic sub-groups of hand OA can be distinguished. Pain and functional difficulties were highest in participants with both thumb and finger OA.

Analysis of Finger Position During Two- and Three-Fingered Grasp: Possible Implications for Terminal Device Design

INTRODUCTION: Analysis of human hand kinesiology has been used to justify the design characteristics of terminal devices. The human hand is a complex mechanical structure consisting of 15 articulations controlled by over 30 muscles for the 5 fingers. It functions as a communication, sensory, grasp and manipulation structure. Separating essential hand kinesiology that is linked with each hand function might allow for the efficient development of terminal devices where there is one primary function such as grasping. It follows that to develop an effective grasping mechanism for a terminal device there should be a clear understanding of hand motions as they relate directly to the grasping function. The conceptual framework used to characterize grasping functions will most likely influence the development of terminal devices. There is a growing body of literature that is refining the way we think of grasping activities, and may impact the design of terminal devices. For example, researchers have described the simplified coordination of hand motions during grasp as “synergies” or “virtual fingers”, where there are predictable dependencies of one finger on another. Using conceptual approaches such as the “virtual fingers” concept will reduce the complexity of the description of the hand/object/task interaction.[2] Recent studies indicate that only a small part of the hand’s potential motion is used during grasp. Mason et al. [5] concluded that much of reach-to-grasp uses a base posture with small refinements in finger and thumb positions. In another study Baud-Bovy & Soechting [1] found that when two fingers oppose the thumb, there is a predictable singular task that produced a balanced lever. Kamper et al [3] studied a variety of grasping tasks using 5 everyday objects. They found that the thumb, for example, used less than 5% of the available range. If one were to extrapolate these findings, prosthetic grasping mechanisms may only need a portion of the hand’s total range of motion. Grasping patterns of the normal hand should be studied using a wide variety of objects to compare normal grasp patterns with prosthetic devices. The current study examined finger positions during twoand three-fingered grasp of a wide range of geometrical objects. The results from people with normal hands were compared to two terminal devices. METHODS: Seven subjects participated in the study (2 male, 5 female). A 6-camera video motion analysis system (Qualisys, Gothenburg, Sweden) was used to collect marker locations in a calibrated volume approximately 1 m 3 . Fourteen reflective markers were taped to the interphalangeal joints, metacarpophalangeal joints and the carpals of the subjects (Figure 1). Seated subjects were asked to grasp objects, one at a time, using either two fingers or three fingers. The 9 objects were chosen based on standard geometric shapes, sizes and varied mass distribution properties. The smallest object was a 1.9 cm diameter sphere and the largest object was a 9.5 X 12.5 X 1.7 cm rectangular prism. The objects were painted brown to avoid inferring a particular use. Data were collected at 120

Thumb Interphalangeal Joint Extension By the Extensor Pollicis Brevis: Association With a Subcompartment and de Quervain's Disease

First dorsal compartment anatomy was analyzed for the presence of a separate compartment for the extensor pollicis brevis (EPB) tendon and the ability of the EPB to extend the thumb interphalangeal (IP) joint in order to determine if these characteristics were associated with each other, and with de Quervain's disease. Two groups were studied: (1) 90 cadaver wrists, 28 to 89 years, 38 male and 52 female specimens; and (2) 143 patient wrists, 21 to 82 years, 18 men and 125 women, in which the first dorsal compartment was released for treatment of de Quervain's disease. The EPB was in a separate compartment in 102 of 143 of the surgical group and 18 of 90 of the cadaver group. The EPB was able to extend the IP joint in 56 of 143 of the surgical group and 19 of 90 of the cadaver group. When the EPB was able to extend the IP joint, it was in a subcompartment in 49 of 56 of the surgical group and 9 of 19 of the cadaver group. When the EPB was able to produce IP extension in the cadaver group, it was inserted on the distal phalanx or the extensor hood. In a substantial number of people undergoing surgery for de Quervain's disease and in cadavers, the EPB can extend the thumb IP joint. When it does, particularly in patients with de Quervain's disease, it is likely to reside in a subcompartment of the first dorsal compartment. The incidences of a subcompartment for the EPB and the ability of the EPB to extend the thumb IP joint were higher in the de Quervain's patient population than in the cadaver group.

Case 2: A teenage boy with epistaxis

A previously well 15-year-old boy presented to the emergency room with a three-month history of intermittent epistaxis, hemoptysis, intermittent low-grade fevers, cough and weight loss. The history began three months before presentation; while he had been participating in ultimate fighting, he was punched in the nose and developed a significant episode of epistaxis. Following this, he developed several more episodes of epistaxis and hemoptysis requiring cautery on three occasions in a community emergency department. During this period, a chest x-ray was performed that was reported as normal. Two months before admission, he developed right-sided otalgia, pharyngitis, and facial pain and tenderness. A computed tomography of his sinuses showed right maxillary sinusitis. A computed tomography of the chest was reported as normal. One month before presentation, his cough worsened. He developed dyspnea, hoarseness and gingival bleeding. The patient’s family doctor had referred him to a local otolaryngologist who had performed sinus lavage, septoplasty for septal perforation and placed tympanostomy tubes 10 days before admission. On review of his systems, the patient disclosed orthopnea, past arthralgia in the right thumb interphalangeal joint and right knee, vertigo and anorexia. He believed that the majority of his 14 kg weight loss had occurred over the past month. He denied any other sites of bleeding, recent travel or sick contacts. His medical history was significant for a two-year history of intermittent recurrent sinusitis treated with antibiotics, multiple tympanostomy tubes for frequent childhood otitis media and mild asthma. His family history was unremarkable. His physical examination revealed an unwell, but nontoxic-appearing boy, who was lying in bed (with the head of the bed tilted at 45 degrees) and breathing shallowly and sweating. His vital signs revealed a temperature of 36.8°C, heart rate of 90 beats/min, respiratory rate of 18 breaths/min, blood pressure of 120/70 mmHg and an oxygen saturation of 95% on room air. His weight was 64 kg, and his height was 172 cm. Head and neck examination revealed friable and bloody gums, and bloody crusts in the nares, but was otherwise normal. On respiratory examination, he had laboured breathing and breathlessness with hoarse speech, inspiratory and expiratory stridor, decreased air entry to the bases of the lungs bilaterally and a prolonged expiratory phase. No wheezes or crackles were audible. The remainder of the examination was unremarkable. On later consultation with the rheumatology consultant, he was found to have small joint effusions of the right thumb interphalangeal joint and the right knee. Initial laboratory studies included a normal complete blood count, electrolytes, blood urea nitrogen, creatinine and coagulation screen. The erythrocyte sedimentation rate was elevated at 40 mm/h. Additional imaging and bloodwork revealed the diagnosis.

Surface projection of the radial tunnel under the supinator muscle: A cadaver study

The purpose of the study was to develop a method for locating surface projections of structures related to the radial tunnel using thumb interphalangeal joint (IPJ) coefficients. Distances from vertical and transverse planes through the lateral epicondyle of the humerus to entry (arcade of Frohse – AF) and exit points of the deep branch of the radial nerve (DBRN) from the supinator muscle were measured on nine cadavers. Average distances were used to find coefficients in terms of IPJ widths. The accuracy of using these coefficients in locating the AF was tested by ink injection on five other cadavers. The average IPJ width from these cadaver upper extremities and from an additional sample of 43 healthy adults was approximately 2.0 cm. The mean transverse plane to entry and exit point distances were 4.2 cm (~2 IPJ widths) and 7.6 cm (~3.8 IPJ widths) respectively. The mean vertical plane to entry and exit point distances were 1.9 cm (~1 IPJ width) and 1.0 cm (~0.5 IPJ width) respectively. Mean radial tunne...

Arthroscopic Synovectomy of the Metacarpophalangeal and Proximal Interphalangeal Joints

Few reports about clinical experience in arthroscopy of finger joints exist. Furthermore, little attention has been given to arthroscopic synovectomy of rheumatoid fingers. Herein, we describe our experience with arthroscopic synovectomy of metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints in patients with rheumatoid arthritis.Arthroscopic synovectomy was performed in 45 finger joints (18 MCP joints, 26 PIP joints, and 1 interphalangeal thumb joint) of 23 patients with rheumatoid arthritis. All procedures were performed on an outpatient basis under regional anesthesia. The diameter of the arthroscope for small joints was 1.5 mm, and a mini shaver system with a 2.5-mm cutter was used for synovectomy. We developed new portals for PIP joints that were established on the dorsolateral aspect at a position more lateral than previously reported portals.Intraarticular structures of finger joints were well visualized, and magnified observation of the articular cartilage and synovial membrane was possible. Because insertion of the instruments into the palmar cavity was not possible without causing damage to the articular surfaces, synovectomy of the palmar capsule could not be performed. However, arthroscopic synovectomy of the dorsal capsule under visual control could be safely performed using the 2-portal technique. None of the patients experienced postprocedural complications. Swelling of each joint disappeared after the procedure and did not return in many cases for a long period. Furthermore, no joints required reoperation.We conclude that arthroscopy of MCP and PIP joints is useful not only for the assessment of articular cartilage and synovium but also for synovectomy in rheumatoid arthritis.

The Natural History of Pediatric Trigger Thumb

Pediatric trigger thumb is a condition of flexion deformity of the interphalangeal joint in children. Although the surgical outcome is satisfactory, the indications for nonoperative treatment for this condition are not clear. The aim of the present study was to determine the rate of resolution of untreated pediatric trigger thumb. Data on seventy-one thumbs in fifty-three children were collected prospectively. The dates of the first visits ranged from April 1994 to March 2004. Patients were diagnosed with pediatric trigger thumb during initial outpatient department visits. During the present study, no treatment such as passive stretching or splinting was applied. The amount of flexion deformity at the thumb interphalangeal joint was measured at every six-month follow-up visit, and the duration of follow-up was at least two years after diagnosis. The end point of follow-up was when the deformity caused pain or secondary deformity or prevented normal use of the hand. The median duration of follow-up was forty-eight months. Of the seventy-one trigger thumbs, forty-five (63%) resolved spontaneously. The median time from the initial visit to resolution was forty-eight months. There was no significant difference in the pattern of resolution between patients with unilateral and bilateral trigger thumb. Although resolution was not observed in the remaining twenty-six thumbs, flexion deformities improved in twenty-two thumbs. For the first two years after the initial visit, the mean flexion deformity significantly decreased over the one-year intervals (p < 0.05). Pediatric trigger thumb can be expected to resolve without treatment in >60% of patients. Moreover, the flexion deformity can be expected to show an improving pattern in patients who do not have resolution. This information may help both parents and surgeons to make decisions regarding the treatment of pediatric trigger thumb.

Clinical Outcome and Histologic Findings of Costal Osteochondral Grafts for Cartilage Defects in Finger Joints

For the purpose of achieving anatomical reduction as precisely as possible, we performed osteochondral grafting from the costo-osteochondral junction in 16 patients (17 joints) with posttraumatic articular cartilage injury or avascular necrosis in finger joints. The purpose of this study was to review our series of costal osteochondral grafts in order to determine the practicality, effectiveness, and functionality of this grafting technique in a clinical setting. Patients were followed for at least 18 months postoperatively (18-57 months; average, 28 months). The injured joints included 3 metacarpophalangeal, 9 proximal interphalangeal, 3 distal interphalangeal, and 2 thumb interphalangeal joints. The defect accounted for 50% to 100% of the articular surface (average, 63%). The average time until bone union of the graft was 58 days. The mean arc of motion was 13 degrees before surgery versus 58 degrees after surgery, with a mean increase of 45 degrees . In 7 patients (8 joints), an extremely small portion (approximately 1 x 1 mm in size and thinner than 0.1 mm) of the implanted cartilage was obtained via biopsy using a scalpel with the consent of the patient at the time of screw removal and was used to prepare histologic specimens, which revealed scattered chondrocytes within the matrix without differences from normal hyaline cartilage in any. The chondrocytes in the grafts appeared viable, and the reconstruction of the joint surface could be confirmed histologically. Osteochondral grafting from the costo-osteochondral junction achieves excellent reconstruction of the injured joint without affecting other joints. This technique is particularly beneficial in cases where it is difficult to obtain allograft donors, as is often the case in Japan. Despite these encouraging findings in this small series, we believe that it is necessary to conduct further studies of this method over a longer period.

Http://www.aott.org.tr/index.php/aott/article/viewFile/3516/1043

The purpose of this study was to evaluate the results of tendon transfers in patients with irreparable radial nerve palsy. The study included 29 patients (5 females, 24 males; mean age 29 years; range 9 to 51 years) who underwent tendon transfers for radial nerve palsy. Four patients had low- and 25 patients had high-level radial nerve palsy. The mean duration of tendon transfer after injury (paralysis time) was 19.7 months (range 1 day to 180 months). Clinical evaluations included joint range of motion and muscle strengths. Functional evaluation was made using the Tajima criteria. The mean follow-up was 56.9 months (range 5 to 90 months). Muscle strengths were measured as follows: 3 (n=3), 4 (n=10), and 5 (n=12) for the wrist extensor muscle; 3 (n=7), 4 (n=10), and 5 (n=12) for the finger extensor muscle; and 3 (n=6), 4 (n=13), and 5 (n=10) for the thumb extensor muscle. The mean wrist range of motion was 67.4 degrees , extension was 48.3 degrees (10 degrees to 70 degrees ), and flexion was 21.5 degrees (10 degrees to 55 degrees ). The mean metacarpophalangeal joint extension was 1.7 degrees (0 degrees to 12 degrees ), thumb abduction was 45.6 degrees (34 degrees to 56 degrees ), and thumb interphalangeal joint extension was 18 degrees (0 degrees to 30 degrees ). According to the Tajima criteria, the results were excellent in 15 patients (51.7%), good in nine patients (31%), and moderate in five patients (17.2%). Eight patients (27.6%) had radial deviation deformity and four patients (13.8%) had 1-level weaker finger extensor muscle strength compared to the other fingers. The flexor carpi ulnaris (FCU) was used in the transfer of patients who developed radial deviation deformity. Treatment of irreparable radial nerve palsy with tendon transfers yields successful results. Radial deviation deformity mostly occurs in patients receiving FCU transfer for finger extension.

Failure of Small Joint Arthrodesis from Resorption Around a Compression Screw in a Patient with Lupus-Associated Arthritis Mutilans: Case Report

We report the unusual case of a patient with systemic lupus erythematosus (SLE)-associated arthritis mutilans. Arthritis mutilans is a variant of erosive arthritis that is more commonly reported with psoriatic and rheumatoid arthritis and not with SLE. Joint fusion has been shown to be the most effective measure to preserve bone length and prevent further erosive joint changes in arthritis mutilans. We attempted to enhance success of a thumb interphalangeal joint fusion in our patient by adding compression across the fusion with implant screws, given the difficulty of achieving solid bone fusion ordinarily. Osteolysis around the compression screw resulted in arthrodesis failure. We were finally able to achieve successful fusion with iliac crest corticocancellous bone grafts and Kirschner wire fixation. Implant athroplasty in patients with bone loss is risky as it often furthers joint instability because of bone resorption around the prosthesis. This is a point of caution regarding use of any implant (including large screws) in patients with arthritis mutilans, as osteolysis around the implant may occur.

Closed rupture of the flexor tendons caused by carpal bone and joint disorders

We analysed 21 patients with closed rupture of the flexor tendons caused by carpal bone and joint disorders. The tendon that ruptured depended on the location of the bone perforation into the carpal tunnel. Radiocarpal arthrography was performed in 13 patients and capsular perforation was demonstrated by contrast medium leakage into the carpal canal in 11 patients. This proved a useful diagnostic test. The flexor tendon(s) were reconstructed with free tendon graft in 17 patients, cross-over transfer of flexor tendons from adjacent digits in two and buddying to an adjacent flexor tendon in one patient. Postoperative total active range of motion in the fingers after 13 free tendon graft reconstructions averaged 213 degrees (range 170-265 degrees ). The active range of motion of the thumb-interphalangeal joint after free tendon graft reconstruction in three cases improved from 0 degrees to 33 degrees on average (range 10 degrees -40 degrees ).

Radiologic findings of the flexor pollicis longus hypoplasia

A case of a 10-year-old boy with hypoplasia of the flexor pollicis longus and without other associated anomalies and trauma history is reported. Flexor pollicis longus tendon anomalies are rare; several types of this congenital anomaly have been reported in the literature. The diagnosis should be considered to the conditions of a patient who was unable to flex the interphalangeal joint of the thumb. Hypoplastic thumb or absent interphalangeal joint crease may be a diagnostic feature in such cases. We preoperatively present the radiological findings of this rare congenital anomaly. Ultrasound and magnetic resonance imaging (MRI) features have never been reported in the literature.

Thumb Function and Appearance in Thrombocytopenia: Absent Radius Syndrome

To evaluate thumb function and appearance in patients with thrombocytopenia absent radius (TAR) syndrome. The size and shape of the 14 thumbs in 7 patients with TAR syndrome were quantified and compared with age-matched normals. Function was assessed using a series of standardized tasks. The thumb length averaged 73% relative to the length of the index finger proximal phalanx (normal, 70%) and 36% relative to the length of the entire index finger (normal, 32%). The thumb/index nail width and girth ratios measured 138% and 101%, respectively (normal, 133% and 105%, respectively). The relative thumb/index thumbnail width-to-girth ratio was 1.36, which was significantly greater than the normal average of 1.27, suggesting the TAR thumbs are relatively wide and flat compared with normal thumbs. The thumb interphalangeal joint was held in a neutral posture and did not show active motion in any patient; the metacarpophalangeal joint was held in a position of flexion and had an average of 32 degrees of extension lag. Patients had difficulty with all activities tested, especially grasping large objects. The thumb in TAR syndrome patients is of relatively normal size and shape; however, the thumb is held in a position of metacarpophalangeal flexion in most patients and function is impaired.

Thumb Arthrodesis

Arthrodesis of the thumb carpometacarpal, metacarpophalangeal, and interphalangeal joints are well-established options in the management of arthritis, instability, and/or deformity. This review includes a general review of the indications and technique of arthrodesis and recent review of the literature. New literature has focused on the role of arthrodesis in managing carpometacarpal arthritis and compared its results with ligament reconstruction and tendon interposition. However, no conclusive evidence demonstrates the superiority of arthrodesis. Several new articles have demonstrated good long-term results of carpometacarpal arthrodesis. A new report on complications associated with plate and screw fixation for carpometacarpal arthritis has been published, leading the authors to conclude that k-wire fixation was a better option. A technique of metacarpophalangeal joint arthrodesis using a cannulated screw has been recently published with good success. Moreover, a cup-in-cone technique of reaming surfaces of the thumb metacarpophalangeal joint to maximize bone contact surface area has been described. Other authors have reiterated and reinforced the success of some of the more standard techniques including Herbert screws for interphalangeal joint arthrodeses. Thumb arthrodesis of the carpometacarpal, metacarpophalangeal, and interphalangeal joints maintains a significant role in the management of deformity and arthritis. Better comparison studies are necessary in evaluating arthrodesis of the carpometacarpal joint versus arthroplasty. New fixation techniques for metacarpophalangeal joint arthrodesis are promising. Standard fixation for interphalangeal joint fusion has been reiterated. Successful arthrodesis can lead to excellent patient outcomes and function.

Use of a Headless Compressive Screw for Distal Interphalangeal Joint Arthrodesis in Digits: Clinical Outcome and Review of Complications

Arthrodesis of the distal interphalangeal joint (DIPJ) or thumb interphalangeal joints can be necessary to treat pain, deformity, or instability associated with arthritis. Compression and rigid fixation are thought to influence fusion rates and time to union favorably. The purpose of the study was to review the clinical outcome and complications associated with the use of a fully threaded headless compression screw for DIPJ arthrodesis. Twenty-seven distal interphalangeal or thumb interphalangeal fusions were performed with an axial Mini-Acutrak screw in 22 patients. Charts, surgical reports, and preoperative and postoperative x-rays were reviewed to determine the incidence, time to union, and complications. The minimal follow-up period was 3 months. Twenty-three of the 27 arthrodeses achieved bony union. Complications included symptomatic nonunion (n=1, treated with secondary fusion), asymptomatic nonunion (n=2, left untreated), infection (n=4; 2 patients required implant removal that resulted in nonunion but declined revision) and nail bed injury (n=3). The Mini-Acutrak screw technique achieves healing rates that are comparable with but not superior to other techniques. Its main advantages are ease of execution, fully buried hardware, and early mobilization; however, the procedure is associated with complications and meticulous technique is required to avoid them. Therapeutic, Level IV.

Development of a Data Glove With Reducing Sensors Based on Magnetic Induction

In this paper, we present the development of a data glove system using magnetic induction coils as finger movement sensors. This data glove has the capability of measuring ten degrees of freedom of a hand with only five sensors that are arranged properly on the palmar surface instead of the dorsal surface. Because these sensors are installed on the finger phalange positions, there is no contact point between the sensors and the finger joints. Hence, the shape of the sensors does not change as the fingers are bending, and the quality of measurement and the lifetime of the sensors will not decrease with time. Additionally, the motion constraints of the finger joints are investigated to simplify the development of the data glove. For the convenience of using this glove, a simple and efficient calibration process consisting of two steps is also provided, so that all required parameters can be determined automatically. The theoretical formulation of the bending angles of proximal interphalangeal, metacarpophalangeal, and thumb interphalangeal joints as well as the calibration equations are derived directly from the positions and orientations of the generator and sensor coils on the data glove. Also described and realized are the circuit block diagram and the construction of the data glove system. To prevent the interference among the generator coils, we adopt the time division method to scan the generator and sensor coils. So far, the experimental results of the sensors performing linear movement and bending angle measurements directly using an oscilloscope in less noisy environments are very satisfactory. It reveals that our data glove is available for a man-machine interface.

Surgery of the Hand in Severe Systemic Sclerosis

Ten patients with scleroderma and severe hand problems required surgery, and seven were available for follow-up (two died from scleroderma-related complications and one was lost to follow-up). The mean duration of follow-up was 4 (range 1.5-9) years. Thirty-three procedures were carried out, including five metacarpophalangeal joint excisional arthroplasties, 13 proximal interphalangeal joint fusions, ten distal interphalangeal joint fusions, and one thumb interphalangeal joint fusion. The metacarpophalangeal joint excision arthroplasties and proximal interphalangeal joint fusions were performed for the correction of severe fixed "finger-in-palm" deformities. Lesions of cutaneous calcinosis were removed in four patients. Fixation was satisfactory in all cases of interphalangeal joint fusion, with no cases of nonunion. Wound healing was satisfactory in six of seven patients. A second surgical procedure was required in three patients for the removal of tension band wires following interphalangeal fusion. Calcinosis was effectively removed using a high-speed dental burr. The results of hand surgery for systemic sclerosis are reliable, but goals must be limited and patient expectations should be modest.

Seventeen-year survivorship analysis of silastic metacarpophalangeal joint replacement .

We reviewed the records and radiographs of 381 patients with rheumatoid arthritis who had undergone silastic metacarpophalangeal joint replacement during the past 17 years. The number of implants was 1336 in the course of 404 operations. Implant failure was defined as either revision or fracture of the implant as seen on radiography. At 17 years, the survivorship was 63%, although on radiographs two-thirds of the implants were seen to be broken. Factors which improved survival included soft-tissue balancing, crossed intrinsic transfer and realignment of the wrist. Surgery to the thumb and proximal interphalangeal joint had a deleterious effect and the use of grommets did not protect the implant from fracture.