Osteointegration of a modular metal-polyethylene surface gliding finger implant: a case report.

INTRODUCTION: Primary press fit and secondary osteointegration is a precondition for component anchoring in articular surface replacements, also in the case of proximal interphalangeal (PIP) joint. Nevertheless, many existing prostheses for the PIP joint have failed to show sufficient osteointegration. CapFlex-PIP(©) implant is a modular metal-polyethylene surface replacement for the PIP joint consisting of a proximal and distal component each having a titanium pore backside, which allows secondary osteointegration at the bone-implant interface. To evaluate osseous integration of this implant, we report a histological analysis of an explantation of a CapFlex-PIP(©) finger implant. CASE PRESENTATION: We present a case of a removed CapFlex-PIP(©) implant due to a soft tissue complication in an 84-year-old woman. The patient received bisphosphonate medication as treatment for osteoporosis. For the histological analysis, the bone-implant contact (BIC) was measured on all stained sections using a Zeiss Axioplan microscope. The summated BIC was 40.7 % for the proximal component and 46.5 % for the distal component of the implant. Histology showed that the implant was in direct contact with the bone at various locations, with no signs of wear or degradation. CONCLUSIONS: This case demonstrates successful osteointegration of the CapFlex-PIP(©) implant. Both components of the investigated implant show osseous integration to an extent which is comparable to that of other load-bearing and articulating implants at different locations in the human body.

A modular surface gliding implant (CapFlex-PIP) for proximal interphalangeal joint osteoarthritis: a prospective case series.

PURPOSE: To evaluate the one-year postoperative clinical and patient-rated outcomes in patients receiving proximal interphalangeal (PIP) joint arthroplasty with a modular surface gliding implant, CapFlex-PIP. METHODS: 10 patients each with primary osteoarthritis of a single PIP joint were assessed preoperatively (baseline), at 6 weeks, and 3, 6, and 12 months after CapFlex-PIP arthroplasty for lateral stability and range of motion of the affected digit. In addition, patients rated their pain using a numeric rating scale and function and overall assessment of their treatment and condition using the quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) and Patient Evaluation Measure (PEM) questionnaires, respectively. RESULTS: The mean baseline active mobility of the affected PIP joint increased from 42° to 51° by one year, although this change was not significant. Patients reported reduced pain at one year, which was statistically significant. There was also a significant improvement between baseline and one-year QuickDASH (43 points vs 15 points, respectively) and PEM scores (51 vs 25 points, respectively). Absent or low lateral instability was observed in 9 joints at follow-up. All implants remained intact over the one-year postoperative period and there was no migration, osteolysis, or implant fracture. After study completion, 2 patients underwent tenolysis. CONCLUSIONS: Patients experienced a significant reduction in pain and a trend towards increased mobility. All implants showed complete osteointegration without evidence of radiological migration. Lateral stability improved. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Packaging--a problem for patients with hand disorders? A cross-sectional study on the forces applied to packaging tear tabs.

INTRODUCTION: Patients with hand disorders frequently experience difficulties opening peelable packaging. PURPOSE: To investigate the forces patients can apply to tear tabs and to compare the results with normative data to make recommendations for the industry and clinical practice. STUDY DESIGN: Descriptive, cross-sectional. METHODS: One hundred patients with hand disorders were studied. The pinch pull force (PPF) applied to tear tabs of different lengths and materials (aluminum, plastic) was measured with a specially designed device. Key pinch was measured with a pinch gauge. Normative data were taken from another study on 402 healthy adults. RESULTS: Patients were able to apply most force to the longest aluminum tab, using the key grip, but this was only 53% of the force exerted by healthy people. Key pinch determines PPF (R(2)=0.548, p≤0.001). CONCLUSIONS: Manufacturers should provide long aluminum tear tabs. Health professionals are encouraged to measure key pinch to detect difficulties in opening packages. LEVEL OF EVIDENCE: Level IV.

Tendon reconstruction for the rheumatoid hand.

Tendon involvement in rheumatoid arthritis is frequent and might even be the first sign of the disease. In long-standing untreated conditions, especially in combination with bony erosions, tenosynovitis may lead to tendon fraying and finally tendon rupture. Tendon reconstruction includes tendon grafting and tendon transfer. Direct repair is almost never possible in patients with rheumatoid arthritis, because the inflammatory process produces extensive tendon damage over a long distance. In patients with significant impaired joint function, additional joint treatment should be planned at the same time as tendon reconstruction.