Five-year results of a new total replacement prosthesis for the finger metacarpo-phalangeal joints

Management of Index Finger Metacarpophalangeal Joint Arthritis

Metacarpophalangeal joint arthritis of the index finger is a debilitating disease often caused by osteoarthritis or inflammatory arthritides such as rheumatoid arthritis. Treatment options include nonsurgical management with nonsteroidal anti-inflammatory drugs, splinting, occupational therapy, corticosteroid injections, and disease-modifying antirheumatic drugs. Operative management options include arthrodesis and arthroplasty, which can be further broken down into silicone implants and 2 component resurfacing implants. The article summarizes the current literature for each of the treatment options for metacarpophalangeal joint arthritis of the index finger.

Silicone and Pyrocarbon Artificial Finger Joints

Artificial finger joint design has been developed through different stages through the past. PIP (proximal interphalangeal) and MCP (metacarpophalangeal) artificial finger joints have come to replace the amputation and arthrodesis options; although, these artificial joints are still facing challenges related to reactive tissues, reduced range of motion, and flexion and extension deficits. Swanson silicone artificial finger joints are still common due to the physician's preferability of silicone with the dorsal approach during operation. Nevertheless, other artificial finger joints such as the pyrocarbon implant arthroplasty have also drawn the interests of practitioners. Artificial finger joint has been classified under three major categories which are constrained, unconstrained, and linked design. There are also challenges such as concerns of infections and articular cartilage necrosis associated with attempted retention of vascularity. In addition, one of the main challenges facing the silicone artificial finger joints is the fracture occurring at the distal stem with the hinge. The aim of this paper is to review the different artificial finger joints in one paper as there are few old review papers about them. Further studies need to be done to develop the design and materials of the pyrocarbon and silicone implants to increase the range of motion associated with them and the fatigue life of the silicone implants.

Biomechanical analysis of metacarpophalangeal joint arthroplasty with metal-polyethylene implant: An in-vitro study

BACKGROUND

The most common implant options for the metacarpophalangeal joint arthroplasty include silicone, pyrocarbon and metal-polyethylene. A systematic review of outcomes of silicone and pyrocarbon implants was conducted; however, a similar exercise for metal-polyethylene implants revealed a scarcity of published results and lack of long-term follow-up studies. The aim of the present work is to test the hypothesis that the magnitude of metacarpophalangeal joint cyclic loads generates stress and strain behaviour, which leads to long-term reduced risk of metal-polyethylene component loosening.

METHODS

This study was performed using synthetic metacarpals and proximal phalanges to experimentally predict the cortex strain behaviour for both intact and implanted states. Finite element models were developed to assess the structural behaviour of cancellous-bone and metal-polyethylene components; these models were validated by comparing cortex strains predictions against the measurements.

FINDINGS

Cortex strains in the implanted metacarpophalangeal joint presented a significant reduction in relation to the intact joint; the exception was the dorsal side of the phalanx, which presents a significant strain increase. Cancellous-bone at proximal dorsal region of phalanx reveals a three to fourfold strain increase as compared to the intact condition. Interpretation The use of metal-polyethylene implant changes the strain behaviour of the metacarpophalangeal joint yielding the risk of cancellous-bone fatigue failure due to overload in proximal phalanx; this risk is more important than the risk of bone-resorption due to the strain-shielding effect. By limiting the loads magnitude over the joint after arthroplasty, it may contribute to the prevention of implant loosening.

Results of the Volar Approach in Proximal Interphalangeal Joint Arthroplasty

Background: Most hand surgeons use a dorsal approach for proximal interphalangeal (PIP) joint implant arthroplasty. However, a volar approach offers the advantage of no disturbance to the extensor mechanism, thus allowing early initiation of active range of motion. We examined our results in patients who underwent PIP joint arthroplasty via a volar approach.

Methods: Using a retrospective chart review, we evaluated the outcomes of patients undergoing PIP joint arthroplasty through a volar approach between 2001 and 2005 by 3 fellowship-trained hand surgeons at our institution. The indication for surgery was PIP joint pain with radiographic evidence of joint destruction. Variables included implant type, diagnosis, affected digit(s), preoperative and postoperative range of motion, and complications. Hand therapy was initiated on postoperative day 3 or 4.

Results: Over the 5 years, 25 PIP joints were replaced in 18 women and 2 men with the volar approach. Replacements consisted of 14 surface replacement prostheses, 9 pyrocarbon prostheses, and 2 silicone prostheses. The average age of patients at prosthesis implantation was 64 years (range, 39–75 years). Prostheses were placed in 1 index, 12 long, 7 ring, and 5 small digits. Average follow-up period was 33 months (range, 24–69 months). Preoperative diagnoses were osteoarthritis (14), rheumatoid arthritis (4), and posttraumatic arthritis (2). Preoperative total arc of motion averaged 42° (range, 0° extension to 80° flexion); postoperative total arc of motion averaged 56° (range, –10° extension to 90° flexion). Complications comprised 1 swan neck deformity, 1 deep infection, 1 dislocation (early), and 2 loose implants with flexion contractures. Seventeen patients had minimal or no pain at their last follow-up visit.

Conclusions: PIP joint arthroplasty can be successfully implemented through a volar approach with various implant types and has outcomes similiar to the published results of the dorsal approach.

Nonrheumatoid Arthritis of the Hand

Arthropathy of the hand is commonly encountered. Contributing factors such as aging, trauma, and systemic illness all may have a role in the evolution of this pathology. Besides rheumatoid arthritis, other diseases affect the small joints of the hand. A review of nonrheumatoid hand arthropathies is beneficial for clinicians to recognize these problems.

Radiographic and surgical considerations in arthritis surgery of the hand

Indications for hand surgeries include unremitting joint pain, deformity and stiffness, often secondary to arthritis. Several surgical options are available, including arthrodesis (fusion) and joint arthroplasty. Classically arthrodesis is performed in situations with poor bone stock and supporting soft tissues. Arthroplasty is reserved for patients and joints in which preservation of function is important and bone stock and soft tissue support are adequate. In this article we will review various techniques for arthrodesis and arthroplasty, their post-surgical imaging appearance, including key findings important to surgeons, and the findings that indicate post-surgical complications. Radiographs are the mainstay for postoperative evaluation and will be the focus of the imaging portions of this review. Advanced imaging modalities will be reviewed when applicable.

Unconstrained metacarpophalangeal joint arthroplasties

Aims

We performed a systematic review of the current literature regarding the outcomes of unconstrained metacarpophalangeal joint (MCPJ) arthroplasty.

Materials and Methods

We initially identified 1305 studies, and 406 were found to be duplicates. After exclusion criteria were applied, seven studies were included. Outcomes extracted included pre- and post-operative pain visual analogue scores, range of movement (ROM), strength of pinch and grip, satisfaction and patient reported outcome measures (PROMs). Clinical and radiological complications were recorded. The results are presented in three groups based on the design of the arthroplasty and the aetiology (pyrocarbon-osteoarthritis (pyro-OA), pyrocarbon-inflammatory arthritis (pyro-IA), metal-on-polyethylene (MoP)).

Results

Results show that pyrocarbon implants provide an 85% reduction in pain, 144% increase of pinch grip and 13° improvements in ROM for both OA and IA combined. Patients receiving MoP arthroplasties had a reduction in pinch strength. Satisfaction rates were 91% and 92% for pyrocarbon-OA and pyrocarbon-IA groups, respectively. There were nine failures in 87 joints (10.3%) over a mean follow-up of 5.5 years (1.0 to 14.3) for pyro-OA. There were 18 failures in 149 joints (12.1%) over a mean period of 6.6 years (1.0 to 16.0) for pyro-IA. Meta-analysis was not possible due to the heterogeneity of the studies and the limited presentation of data.

Conclusion

We would recommend prospective data collection for small joint arthroplasties of the hand consisting of PROMs that would allow clinicians to come to stronger conclusions about the impact on function of replacing the MCPJs. A national joint registry may be the best way to achieve this. Cite this article: Bone Joint J 2017;99-B:100–6.

Currently available metacarpophalangeal prostheses: their designs and prospective considerations

Although implanted for over 40 years, finger prostheses have failed to match the success achieved by artificial hip and knee prostheses, despite a myriad of designs having been proposed and implanted. This article looks at the currently available designs of metacarpophalangeal prosthesis, both single-piece and multicomponent implants. An appraisal of their designs and the clinical results, where available, are provided. The review also considers the challenges that are still faced by bioengineers and surgeons concerned with improving the success of metacarpophalangeal prostheses. In addition, key current areas of concern such as in vitro testing and contemporary issues in rheumatology, which may be diminishing the amount of metacarpophalangeal arthroplasty taking place, are discussed.

Surface replacement arthroplasty of the proximal interphalangeal and metacarpophalangeal joints: The current state

Surface replacement arthroplasty for proximal interphalangeal joint and metacarpophalangeal joints are becoming popular. Low profile, anatomically designed implants limit the amount of bone removed but need preservation of the collateral ligaments. Pyrocarbon and cobalt-chrome stemmed unconstrained implants on ultra-high molecular weight polyethylene are the two commonly available bearing surfaces. The indications for small joint arthroplasty are degenerative, post-traumatic or rheumatoid arthritis. Early results are encouraging, primarily in patient satisfaction and pain relief, but are based on low numbers. The main concerns are progressive loss of range due to implant settling, dislocation, squeaking and poor osteo-integration with the appearance of a radiolucent line at the bone-implant interface. Our experience suggests that metacarpophalangeal joint replacements consistently give good results.

Complications of small joint arthroplasty

Arthritis in the small joints of the hand can be treated with arthrodesis or arthroplasty. Arthrodesis has known risks of infection, pain, and nonunion. Distal interphalangeal (DIP) arthroplasty has been successful in preserving motion and alleviating pain for distal DIP, proximal interphalangeal, and metacarpophalangeal joints. Unfortunately, complications arise that limit the success of surgery. Silicone implants have been reliable for many years but still present with the risks of infection, implant breakage, stiffness, and pain. Newer implant designs may limit some of these complications, but present with unique problems such as dislocations and loosening. It is not yet clear as to which type of implant provides the most reliable results, although implant arthroplasty appears to give better function than arthrodesis. Silicone arthroplasty does not lead to silicone synovitis and is a reliable procedure. Pyrocarbon implants are showing some promise, particularly in the osteoarthritic patient.

Preliminary results of nonconstrained pyrolytic carbon arthroplasty for metacarpophalangeal joint arthritis

PURPOSE

To review early outcomes of arthritic metacarpophalangeal (MCP) joints treated with nonconstrained pyrolytic carbon implants to evaluate efficacy, clinical outcomes, and durability.

METHODS

One hundred forty-two consecutive arthroplasties (61 patients) were retrospectively reviewed. Diagnoses included osteoarthritis (OA), traumatic arthritis, and inflammatory arthritis. One hundred thirty were primary joint replacements, and 12 were prior-silicone revisions. The average patient age was 55 years (range, 21-77 years); 36 patients were women and 25 were men. Average follow-up period was 17 months (range, 3-42 months), and 43 patients were followed up for a minimum of 1 year.

RESULTS

For OA patients, according to the analog pain scale used, pain decreased from 73.0 to 8.5 of 100, functionality increased from 20.1 to 86.6 of 100, and appearance improved from 62.7 to 93.6 of 100. The rheumatoid arthritis (RA) group showed decreased pain from 43.1 to 8.9 of 100, functional improvement from 26.7 to 83.3 of 100, and increased appearance from 25.2 to 77.1 of 100. At 1 year, satisfaction was greater than 90% for both groups. Arc of motion for OA patients improved from 44 degrees to 58 degrees . Oppositional pinch increased 126%, and grip strength improved 40%. Rheumatoid arthritis patients increased their MCP joint motion arc from 32 degrees to 45 degrees . Oppositional pinch increased 89%, but grip strength decreased. Radiographs at 1 year demonstrated stable prostheses in all of the OA joints. The RA group overall demonstrated evidence of axial subsidence (10.5% of joints) and periprosthetic erosions (16.4% of joints). In RA joints with greater than 1-year follow-up period, 55.0% had axial subsidence, 95.0% had an increased radiolucent seam, and 45.0% had periprosthetic erosions. The overall implant survivorship is 141 joints to date. The overall minor complication rate was 6%, and major complication rate was 9%.

CONCLUSIONS

Preliminary results suggest that pyrolytic carbon MCP joint arthroplasty provides good pain relief, patient satisfaction, and functional improvement in managing OA and select cases of RA. Longer follow-up evaluation will help validate these promising early results.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Prediction of lubrication regimes in two-piece metacarpophalangeal prostheses

Various designs of two-piece finger prosthesis with conforming spherical surfaces have been proposed. These were compared by calculating the lubrication regime for the material combinations and operating conditions expected at the metacarpophalangeal joints of the fingers. Consideration was given to a range of loads from 2 to 50 N, a range of entraining velocities from 0 to 30 mm/s, and a range of prosthesis radii from 3 to 10 mm. This theoretical lubrication analysis indicated that the optimum material combination of those available for two-piece metacarpophalangeal prostheses is in the order: ceramic-on-ceramic; metal-on-metal; pyrocarbon-on-pyrocarbon; and metal-on-polymer. However, it should be recognised that other factors may take precedence when choosing a material combination for a design of finger prosthesis.

Thumb metacarpophalangeal arthritis: arthroplasty or fusion?

The human thumb assumes 50% of the workload of the human hand, and is therefore the most important digit. As such, the thumb has a propensity for the development of osteoarthritis. Moreover, the thumb is also often diseased, in anywhere from 68% to 80%of patients who have rheumatoid arthritis. Much attention over the years has been given to the carpalmetacarpal joint of the thumb, whereas the metacarpophalangeal (MP) joint of the thumb remains largely unstudied. The purpose of this article is to review the etiology of thumb MP joint arthritis, and discuss the different treatment options of this condition.

Nonrheumatoid metacarpophalangeal joint arthritis. Unconstrained pyrolytic carbon implants: indications, technique, and outcomes

Unconstrained pyrolytic surface replacement arthroplasty provides the benefits of a more natural center of rotation with preservation of native ligamentous joint stability. Initial short-term results show excellent motion, pain relief, and restoration of pinch and grip strength. These results are encouraging, and suggest that pyrolytic carbon arthroplasty may be a reasonable option for joint salvage in patients suffering from MP joint osteoarthritis.

Short-term results of the Ascension™ pyrolytic carbon metacarpophalangeal Joint replacement arthroplasty for osteoarthritis

INTRODUCTION

Osteoarthritis of the metacarpophalangeal joints is difficult to manage due to the high demands placed on any prosthesis. We report the preliminary results of our experience using the Ascension pyrolytic carbon implant.

METHOD

A pyrocarbon metacarpophalangeal joint replacement was implanted into seven patients (10 metacarpophalangeal joints) with osteoarthritis. Patients were reviewed both clinically and radiologically.

RESULTS

At a mean follow-up of 2.2 years (1-4 years) there were no implant failures nor loosenings. Pain scores improved from 68% to 3% postoperatively, and there was a very high rate of patient satisfaction.

CONCLUSION

Pyrocarbon implants are a promising solution to a condition which may be otherwise difficult to treat surgically.