Validity and Responsiveness of Forearm Strength Measurements in the Evaluation of Distal Radioulnar Joint Implant Arthroplasty.

PURPOSE: To assess the responsiveness of forearm strength tests and to correlate the change to grip strength and a patient-reported outcome measure used for evaluation of distal radioulnar joint (DRUJ) implant arthroplasty. METHODS: We performed a retrospective review of 18 patients treated with Herbert (n = 12) and Scheker (n = 6) DRUJ implants. Patients who had undergone the various measurements of arm and grip strength both before surgery and after a minimum follow-up of 1 year were included. Our primary aim was to compare the responsiveness of grip strength with our new methods for measuring forearm torque and lifting strength. The secondary aim was to correlate observed changes in strength measurements to change in a patient-reported outcome measure with use of the patient-reported wrist evaluation (PRWE). Measurements of grip strength, forearm torque, and lifting strength were performed with the Jamar dynamometer and the Kern and Baseline instruments. Preoperative values were compared with 1-year values. RESULTS: Standardized response mean and effect size values were higher for forearm torque than for grip strength. Change in forearm torque and lifting strength had a moderate to strong correlation with change in PRWE. The correlation between grip strength and PRWE was weak. CONCLUSIONS: Forearm torque measurements were better than grip strength in detecting changes after DRUJ arthroplasty. It also had a stronger correlation to patient-reported outcome, measured with the PRWE. CLINICAL RELEVANCE: Forearm torque testing may add further information to the evaluation of DRUJ disorders and their treatments. These tests can provide quantifiable data on the patient's ability to perform various tasks requiring physical strength.

Ulnar Head Replacement: 21 Cases; Mean Follow-Up, 7.5 Years.

PURPOSE: To report clinical and radiographic outcomes for the Herbert ulnar head prosthesis after a mean of 7.5 years (range, 2.0-12.5 years). METHODS: We performed 22 Herbert ulnar head prosthesis arthroplasties between 2000 and 2011. Five were primary procedures, and the remaining 17 were done after an average of 2 (range, 1-5) previous operations. The mean age at surgery was 55 years (range, 31-74 years). Follow-up including clinical examination, standardized questionnaires, and radiographic examination was done after mean 7.5 years (range, 2.0-12.5 years) in 21 cases. We used the Disabilities of the Arm, Shoulder, and Hand questionnaire, the Patient-Rated Wrist Evaluation questionnaire, and the Mayo wrist score questionnaire. Pain and satisfaction were evaluated with a 10-cm visual analog scale (VAS). Measurements of range of motion and strength for grip were recorded. RESULTS: Wrist range of motion was not affected by the arthroplasty except for supination, which significantly improved from 55° to 70°. At follow-up, grip strength averaged 25 kg (range, 10-48 kg) in the operated wrists and 31 kg (range, 8-74 kg) on the contralateral side. Visual analog scale-pain averaged 2.9 (range, 0-8.7) during activity and 1.7 (range, 0-7) at rest. Satisfaction VAS was 8.9 (range, 4.3-10). Five patients had VAS-pain above 5 during activity, and 1 patient was dissatisfied and regretted having undergone arthroplasty. Mean outcomes were 27 (range, 5-50) for Disabilities of the Arm, Shoulder, and Hand measure, 31 (range, 0-90) for the Patient-Rated Wrist Evaluation score, and 71 (range, 30-90) for the Mayo wrist score. One patient was reoperated with capsuloplasty 9 months after the arthroplasty owing to recurrence of painful instability. Full stability was not achieved but the pain resolved. None of the implants showed any radiographic signs of loosening. CONCLUSIONS: The Herbert ulnar head prosthesis was a safe method of treatment and provided satisfactory midterm results for selected cases of distal radioulnar joint disorders. CLINICAL RELEVANCE: Increased knowledge of performance for ulnar head implant arthroplasty may aid surgical decision making for distal radioulnar joint disorders. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Constrained implant arthroplasty as a secondary procedure at the distal radioulnar joint: early outcomes.

PURPOSE: To evaluate the clinical and radiological outcomes for the Scheker total joint endoprosthesis when used for previously failed surgeries of the distal radioulnar joint (DRUJ). METHODS: Eight patients with DRUJ derangement with painful instability and 1 patient with DRUJ synostosis received a Scheker DRUJ total joint endoprosthesis between 2006 and 2010. All patients had at least 1 procedure previously performed on the distal ulna (mean, 3.6 procedures). The follow-up time was on average 3.7 years (range, 2-5 y). Standardized preoperative and postoperative assessments included radiographic examination, evaluation of pain by a visual analog scale, and measurements of range of motion and grip strength. We evaluated patient-perceived function with the Disabilities of the Arm, Shoulder, and Hand questionnaire. RESULTS: There was significant improvement in pain and Disabilities of the Arm, Shoulder, and Hand scores. Grip strength was improved but not significantly. Range of motion was not impaired. We encountered no major complications. Radiographic evaluation showed bone resorption at the distal ulna for most patients and at the tip of a screw in 1 patient, but we found no evidence of implant loosening. CONCLUSIONS: Our short-term results in a limited patient series show that in selected cases, the Scheker total joint endoprosthesis is a safe and efficient treatment option for previously failed surgeries of the DRUJ. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

The Artelon CMC spacer compared with tendon interposition arthroplasty.

BACKGROUND AND PURPOSE: The Artelon CMC spacer is designed for surgical treatment of osteoarthritis (OA) in the carpometacarpal joint of the thumb (CMC-I). Good results using this degradable device were previously presented in a pilot study. We now present results from a larger randomized, controlled, multicenter study. PATIENTS AND METHODS: 109 patients (94 females) with a mean age of 60 (42-83) years, suffering from painful CMC OA, were included in the study at 7 centers in Sweden. The patients were randomized to Artelon CMC spacer (test, n = 72) or tendon arthroplasty (control, n = 37) at a ratio of 2:1. Perceived pain was recorded on a visual analog scale (VAS) before treatment and after 3, 6, and 12 months, when measuring maximal tripod pinch strength (primary outcome measure). In addition, range of motion, radiographic findings, and functional testing were recorded pre- and postoperatively. RESULTS: Swelling and pain were more common in the test group and 6 implants were removed because of such symptoms. 5 of these patients did not receive antibiotics preoperatively according to the study protocol. In a per-protocol analysis, i.e. patients without signs of concomitant OA in the scaphoid-trapezium-trapezoid (STT) joint and those in the test group who received antibiotics, the mean difference in tripod pinch strength increase, adjusted for baseline, was 1.4 kg in favor of the test group (not statistically significant). Statistically significant pain relief was achieved in both groups, with perceived pain gradually decreasing during the follow-up period. In the intention-to-treat analysis but not in the per-protocol analysis, significantly better pain relief (VAS) was obtained in the control group. Patient-perceived disability evaluated by the DASH questionnaire improved in both groups. INTERPRETATION: The Artelon CMC spacer did not show superior results compared to tendon interposition arthroplasty. Proper use of preoperative antibiotics and a thorough patient selection appear to be important for the results.

A six-week hand exercise programme improves strength and hand function in patients with rheumatoid arthritis.

OBJECTIVE: To evaluate the effects of hand exercise in patients with rheumatoid arthritis, and to compare the results with healthy controls. METHODS: Forty women (20 patients with rheumatoid arthritis and 20 healthy controls) performed a hand exercise programme. The results were evaluated after 6 and 12 weeks with hand force measurements (with a finger extension force measurement device (EX-it) and finger flexion force measurement with Grippit). Hand function was evaluated with the Grip Ability Test (GAT) and with patient relevant questionnaires (Disability of the Arm, Shoulder, and Hand (DASH) and Short Form-36). Ultrasound measurements were performed on m. extensor digitorum communis for analysis of the muscle response to the exercise programme. RESULTS: The extension and flexion force improved in both groups after 6 weeks (p < 0.01). Hand function (GAT) also improved in both groups (p < 0.01). The rheumatoid arthritis group showed improvement in the results of the DASH questionnaire (p < 0.05). The cross-sectional area of the extensor digitorum communis increased significantly in both groups measured with ultrasound. CONCLUSION: A significant improvement in hand force and hand function in patients with rheumatoid arthritis was seen after 6 weeks of hand training; the improvement was even more pronounced after 12 weeks. Hand exercise is thus an effective intervention for rheumatoid arthritis patients, leading to better strength and function.

Ultrasound evaluation in combination with finger extension force measurements of the forearm musculus extensor digitorum communis in healthy subjects.

BACKGROUND: The aim of this study was to evaluate the usefulness of an ultrasound-based method of examining extensor muscle architecture, especially the parameters important for force development. This paper presents the combination of two non-invasive methods for studying the extensor muscle architecture using ultrasound simultaneously with finger extension force measurements. METHODS: M. extensor digitorum communis (EDC) was examined in 40 healthy subjects, 20 women and 20 men, aged 35-73 years. Ultrasound measurements were made in a relaxed position of the hand as well as in full contraction. Muscle cross-sectional area (CSA), pennation angle and contraction patterns were measured with ultrasound, and muscle volume and fascicle length were also estimated. Finger extension force was measured using a newly developed finger force measurement device. RESULTS: The following muscle parameters were determined: CSA, circumference, thickness, pennation angles and changes in shape of the muscle CSA. The mean EDC volume in men was 28.3 cm3 and in women 16.6 cm3. The mean CSA was 2.54 cm2 for men and 1.84 cm2 for women. The mean pennation angle for men was 6.5 degrees and for women 5.5 degrees . The mean muscle thickness for men was 1.2 cm and for women 0.76 cm. The mean fascicle length for men was 7.3 cm and for women 5.0 cm. Significant differences were found between men and women regarding EDC volume (p < 0.001), CSA (p < 0.001), pennation angle (p < 0.05), muscle thickness (p < 0.001), fascicle length (p < 0.001) and finger force (p < 0.001). Changes in the shape of muscle architecture during contraction were more pronounced in men than women (p < 0.01). The mean finger extension force for men was 96.7 N and for women 39.6 N. Muscle parameters related to the extension force differed between men and women. For men the muscle volume and muscle CSA were related to extension force, while for women muscle thickness was related to the extension force. CONCLUSION: Ultrasound is a useful tool for studying muscle architectures in EDC. Muscle parameters of importance for force development were identified. Knowledge concerning the correlation between muscle dynamics and force is of importance for the development of new hand training programmes and rehabilitation after surgery.

Results from a degradable TMC joint Spacer (Artelon) compared with tendon arthroplasty.

PURPOSE: A new spacer for the trapeziometacarpal joint (TMC) based on a biological and tissue-preserving concept for the treatment of TMC osteoarthritis (OA) has been evaluated. The purpose was to combine a spacing effect with stabilization of the TMC joint. METHODS: Artelon (Artimplant AB, Sweden) TMC Spacer is synthesized of a degradable polyurethaneurea (Artelon), which has been shown to be biocompatible over time and currently is used in ligament augmentation procedures. Fibers of the polymer were woven into a T-shaped device in which the vertical portion separates the bone edges of the TMC joint and the horizontal portion stabilizes the joint. Fifteen patients with disabling pain and isolated TMC OA were included in the study. Ten patients received the spacer device and the remaining 5 (control group) were treated with a trapezium resection arthroplasty with abductor pollicis longus (APL) stabilization. The median ages of the 2 groups were 60 and 59 years, respectively. Pain, strength, stability, and range of motion were measured before and after surgery. Radiographic examination was performed in all patients before and after surgery. At follow-up evaluation 3 years after surgery an unbiased observer evaluated all patients. Biopsy specimens were obtained from 1 patient 6 months after surgery. RESULTS: All patients were stable clinically without signs of synovitis. In both groups all patients were pain free. The median values for both key pinch and tripod pinch increased compared with before surgery in the spacer group but not in the APL group. The biopsy examinations showed incorporation of the device in the surface of the adjacent bone and the surrounding connective tissue. No signs of foreign-body reaction were seen. CONCLUSIONS: This study showed significantly better pinch strength after Artelon TMC Spacer implantation into the TMC joint compared with APL arthroplasty.

Radiographic evaluation of osseointegration and loosening of titanium implants in the MCP and PIP joints.

PURPOSE: Good to excellent clinical results have been shown in the initial studies on osseointegrated metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joint implants that consist of a flexible silicone spacer connected to osseointegrated titanium fixtures. A high fracture rate of the silicone spacer, however, has been reported, diminishing the value of this implant system. The purpose of this study was to evaluate the osseointegration of the titanium fixture itself in a large study group and compare patients with rheumatoid arthritis with those with osteoarthrosis as a base for further development of the implant concept. METHODS: Two hundred thirty-nine implants (27 PIP, 212 MCP) in 86 patients were retrospectively evaluated radiographically. Two hundred implants were in patients with rheumatoid arthritis. Radiographic evaluation included measuring the length and width of resorption zones around the titanium fixtures. A scoring system was used that grouped observations in 4 groups, from 0 (little or no change) to 3 (loosening). Status of the silicone spacer was also noted. RESULTS: At follow-up evaluation an average of 41 months (range, 12-103 months) after surgery, complete osseointegration was found in 450 of 478 fixtures (94%). Loosening was found in 10 proximal and 18 distal fixtures. The proximal fixtures showed loosening mainly during the first 3 years after surgery and the distal fixtures also had loosening. In the 31 MCP joint implants that were evaluated for more than 5 years, the osseointegration rate was 97%. CONCLUSIONS: Implant stem fixation with osseointegrated titanium fixtures is a valuable method that works well in rheumatoid arthritis patients. Further development will focus on a more durable constrained joint mechanism.

Early results of the Universal total wrist arthroplasty in rheumatoid arthritis.

Early results of 2 surgeons involved in a prospective study of the Universal total wrist prosthesis (KMI, San Diego, CA) are reported. Twenty-two prostheses were implanted in 19 patients for the treatment of severe rheumatoid arthritis. Two-year follow-up results of 8 wrists and 1-year follow-up results of 14 wrists were reviewed. Total arcs of motion (flexion-extension, radial-ulnar deviation, and pronation-supination) all improved significantly after arthroplasty. Individual motions that were most limited before surgery (extension, radial deviation, and supination) improved the most. Disabilities of the Arm, Shoulder, and Hand outcome scores improved 14 points at 1 year and 24 points at 2 years. Three prostheses (14%) were unstable and required further treatment; all 3 were in patients with highly active disease and severe wrist laxity. The Universal prosthesis provides a good early outcome in rheumatoid patients without severe preoperative wrist laxity.