Correlation between range of motion and implant fracture: a 5 year follow-up of 72 joints in 18 patients in a randomized study comparing Swanson and Avanta/Sutter MCP silicone prosthesis

Long-Term Implant Fracture Rates Following Silicone Metacarpophalangeal Joint Arthroplasty in Rheumatoid Arthritis

PURPOSE

The primary objective of this study was to compare the long-term survival rates of silicone metacarpophalangeal (MCP) arthroplasties between two major implants in patients with rheumatoid arthritis, using implant fracture as an end point. We also evaluated the difference in postoperative function between patients with fractured and intact implants as a secondary objective.

METHODS

A retrospective cohort study was conducted on 372 fingers of 133 hands that underwent silicone MCP arthroplasty between January 2000 and June 2019 (mean follow-up, 7.6 years). The survival rates of Swanson-type and Sutter-type implants were compared, using implant fracture as the end point after a radiographic evaluation. Clinical measures and upper limb functional assessments using the Disabilities of the Arm, Shoulder, and Hand (DASH) score were performed in the nested cohort.

RESULTS

The 10.6-year survival rates for implant fracture of Swanson- and Sutter-type implants were 86.2% and 9.4%, respectively, with significantly higher survival noted for Swanson-type implants. The Sutter-type implant showed increased susceptibility to fracture in all four fingers compared to the Swanson-type implant. Implant fractures were primarily observed at the stem-hinge junction. There were no significant differences in upper limb function between the fractured and intact implant groups.

CONCLUSIONS

Sutter-type implants were found to be more prone to fracture compared with Swanson-type implants. However, implant fractures did not significantly affect upper limb function.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognosis IV.

The silicone metacarpophalangeal joint arthroplasty: An in-vitro analysis

BACKGROUND

Silicone is still the gold standard implant in metacarpophalangeal arthroplasty. Whereas the clinical results are acceptable, in follow-ups with >10 years, high rates of implant fracture are common, and 5 to 7% of implants required revision. This work's purpose is to analyse the hypothesis that the joint flexion amplitude has a relevant effect on bone strain level, implant stress and bone-implant micromotion, which can reflect an increase in the risk of bone resorption/fatigue failure, implant fracture and osteolysis.

METHODS

To experimentally predict the cortical loading behaviour, composite metacarpals and proximal phalanges were used in intact and implanted states. A finite element model was developed to evaluate the structural behaviour of cancellous bone and implant. This model was validated by comparing cortical strain and load-displacement curve with experimental measurements.

FINDINGS

Bone strain changes between the intact and the implanted states showed a load transfer effect from the cortical to the cancellous bone that increases significantly with the flexion's amplitude rise. The peak implant stress occurred in the flexion amplitudes further away from the implant neutral angle. The highest implant pistoning motion and the highest phalanx cancellous-bone strain occurred simultaneously at the maximum flexion amplitude.

INTERPRETATION

Limiting joint flexion range will be helpful to reduce the strain-shielding effect on cortical bone, minimizing the overload effect on cancellous bone and decreasing the stress levels and the pistoning motion on the implant, ultimately contributing to the longevity of silicone arthroplasty.

In Vivo Metacarpophalangeal Joint Kinematics After Silicone Implant Arthroplasty in Patients With Rheumatoid Arthritis

PURPOSE

The aim of this study was to determine the potential mechanism of implant fracture using 3-dimensional motion analysis of patients with rheumatoid arthritis.

METHODS

Active flexion motion in 9 hands (34 fingers) of 6 female patients with rheumatoid arthritis who previously underwent hinged silicone metacarpophalangeal joint arthroplasty was examined using 4-dimensional computed tomography. Positions of the proximal phalanges relative to the metacarpals were quantified using a surface registration method. The deformation of the silicone implant was classified in the sagittal plane in the maximum flexion frame. The longitudinal bone axis of the proximal phalanx and the helical axis of the proximal phalanx were evaluated in 3-dimensional coordinates based on the hinge of the silicone implant.

RESULTS

Nineteen fingers were classified into group 1, in which the silicone implant moved volarly during flexion without buckling of the distal stem. Twelve fingers were classified into group 2, in which the distal stem of the silicone implant buckled. Three fingers were classified into group 3, in which the base of the distal stem had already fractured. Quantitatively, the longitudinal bone axes of the proximal phalanges were displaced from dorsal to volar in the middle stage of flexion and migrated in the proximal direction in the late phase of flexion. The helical axes of the proximal phalanges were located on the dorsal and proximal sides of the hinge, and these tended to move in the volar and proximal directions as the metacarpophalangeal joint flexed.

CONCLUSIONS

Volar and proximal translation of the proximal phalange was observed on 4-dimensional computed tomography.

CLINICAL RELEVANCE

Proximal displacement of the bone axis late in flexion appears to be a contributing factor inducing implant fractures, because the pistoning motion does not allow the implant to move in the proximal direction.

Risk Factors Contributing to Early Implant Fracture in Silicone Metacarpophalangeal Joint Arthroplasty for Patients With Rheumatoid Arthritis

PURPOSE

To identify the risk factors associated with early implant fracture of silicone metacarpophalangeal (MCP) joint arthroplasty using the volar hinge silicone implant for patients with rheumatoid arthritis.

METHODS

We retrospectively reviewed 113 fingers of 31 hands that underwent MCP joint arthroplasty between 2008 and 2014, with a minimum follow-up of 3 years,. An implant fracture within 3 years after surgery was regarded as an early implant fracture. Patient records were reviewed for potential risk factors of age, affected fingers, ulnar drift angle, and range of motion of the MCP joint before surgery and 1 year after surgery. Candidate risk factors were compared at the level of the digit and at the patient level.

RESULTS

With fracture of the implants as the end point, Kaplan-Meier estimated survival rate was 74.3% at 3 years and 67.9% at 5 years. Early implant fracture was detected in 29 fingers. Bivariate analyses showed significant associations between early implant fracture and MCP joint arc of motion before surgery, MCP joint flexion range 1 year after surgery, and MCP joint arc of motion 1 year after surgery. Multiple logistic regression analysis showed that increased MCP joint flexion range 1 year after surgery was an independent risk factor for early implant fracture.

CONCLUSIONS

Increasing MCP joint flexion range was associated with increased fractures of the implants. We propose that the MCP joint flexion range should be restricted to less than 60° in postoperative rehabilitation; it is necessary to educate the patient to permanently avoid excessive flexion of the MCP joint.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Seven-Year Outcomes of the Silicone Arthroplasty in Rheumatoid Arthritis Prospective Cohort Study

OBJECTIVE

Rheumatoid arthritis (RA) causes destruction of the metacarpophalangeal (MCP) joints, leading to hand deformities, pain, and loss of function. This study prospectively assessed long-term functional and health-related quality-of-life outcomes in RA patients with severe deformity at the MCP joints.

METHODS

RA patients between ages 18 to 80 years with severe deformity at the MCP joints were referred to 1 of the 3 study sites. Subjects who elected to undergo silicone metacarpophalangeal joint arthroplasty (SMPA) while continuing with medical management were followed in the SMPA cohort. Subjects who elected to continue with medical management alone without surgery were followed in the non-SMPA cohort. Objective measurements included grip and pinch strength as well as arc of motion, ulnar drift, and extensor lag of the MCP joints. Patient-reported outcomes included the Michigan Hand Questionnaire (MHQ) and the Arthritis Impact Measurement Scales questionnaire. Radiographs of SMPA implants were assessed and graded as intact, deformed, or fractured.

RESULTS

MHQ scores showed large improvements post-SMPA, and baseline-adjusted expected outcomes in the SMPA group were significantly better at year 7 in function, aesthetics, satisfaction, and overall score compared to non-SMPA. SMPA subjects did not improve in grip or pinch strength, but achieved significant improvement and maintained the improvement long term in ulnar drift and extensor lag.

CONCLUSION

Benefits of the SMPA procedure are maintained over 7 years with low rates of implant fracture or deformity. Non-SMPA patients remained stable in their hand function over the 7-year study duration.

The design and development of a finger joint simulator

Artificial finger joints lack the long-term clinical success seen with hip and knee prostheses. In part, this can be explained by the challenges of rheumatoid arthritis, a progressive disease which attacks surrounding tissues as well as the joint itself. Therefore, the natural finger joints’ biomechanics are adversely affected, and consequently, this imbalance due to subluxing forces further challenges any prosthesis. Many different designs of finger prosthesis have been offered over a period of greater than 50 years. Most of these designs have failed, and it is likely that many of these failures could have been identified had the prostheses been appropriately tested prior to implantation into patients. While finger joint simulators have been designed, arguably only those from a single centre have been able to reproduce clinical-type failures of the finger prostheses tested in them. This article describes the design and development of a finger simulator at Durham University, UK. It explains and justifies the engineering decisions made and thus the evolution of the finger simulator. In vitro results and their linkage to clinical-type failures are outlined to help to show the effectiveness of the simulator. Failures of finger implants in vivo continue to occur, and the need for appropriate in vitro testing of finger prostheses remains strong.

The management of complications of small joint arthrodesis and arthroplasty

Arthrodesis and arthroplasty are surgical options used for the management of pain, stiffness, deformity, and instability related to arthritis and traumatic injury of the small joints of the hand. Arthrodesis and arthroplasty come with a risk of postoperative infection. Superficial soft tissue infections can often be managed with oral antibiotics alone. Deep infections and osteomyelitis frequently require removal of hardware in addition to antibiotics and may require surgical revision once the infection is cleared. Selection of the most appropriate revision technique depends on the underlying cause of the initial failure, patients' functional and outcome needs, and surgeon preference.

Is Swanson prosthesis better than Sutter prosthesis for metacarpophalangeal joint arthroplasty? A meta-analysis

The aim of this meta-analysis is to compare the outcomes of the Swanson and Sutter prostheses (previously the Avanta prosthesis) used for metacarpophalangeal joint arthroplasty, and provide a powerful and rational conclusion regarding the use of prosthesis in MCP joint surgery. The literature search was based on PubMed, Cochrane Library, MEDLINE, EMBASE, and the Chinese National Knowledge Infrastructure. Data were evaluated using a generic evaluation tool designed by the Cochrane Bone, Joint, and Muscle Trauma Group and analysed using RevMan, version 5.0. Six randomised controlled trials were contained in this review, and five of them involving 143 patients were included in the meta-analysis. The results suggested that using the Sutter prosthesis could significantly decrease the rates of recurrence of drift when compared with the Swanson prosthesis for metacarpophalangeal joint arthroplasty (OR = 2.05, 95% Confidence interval (CI) = 1.31-3.20, p = 0.002). No significant difference in the outcomes of prosthesis fracture was found in two groups (OR = 1.07, 95% CI = 0.41-2.79, p = 0.88). Due to the limited data, the outcomes of range of motion, correction of ulnar deviation, pain, grip strength, and radiographic osteolytic changes could not be included in the meta-analyses. Theoretically, recurrence of drift was more common with Swanson prosthesis when compared with the Sutter prosthesis. No significant difference in the outcomes of prosthesis fracture was observed in two groups. More high-quality studies are required in long-term follow-up.

Metacarpophalangeal joint arthritis

Arthritis of the metacarpophalangeal joint can result in considerable disability and pain. Inflammatory, posttraumatic, crystalline, and osteoarthritis are common etiologies of joint disease. A variety of nonsurgical treatment options have been shown to be effective, including activity modification, anti-inflammatory medications, splinting, and cortisone injections. In addition, newer generation disease-modifying antirheumatic drugs geared toward the treatment of rheumatoid arthritis have shown promise in retarding the inflammatory process. Another, relatively newer, conservative treatment option includes topical anti-inflammatories such as diclofenac sodium that are now approved by the Federal Drug Administration. Surgical treatment options most commonly include arthroplasty and arthrodesis. In the treatment of thumb metacarpophalangeal arthritis, arthrodesis is a popular and generally reliable surgical solution. In the fingers, arthroplasty remains the most common treatment option. Traditional constrained silicone joint replacements remain the most commonly used. Newer generation, unconstrained, surface replacement arthroplasties have shown promise in the treatment of osteoarthritis and select cases of inflammatory arthritis in which there is good bone stock, no or minimal deformity, adequate supporting soft tissues, and good disease control.