Phalangeal Component Research Articles

A novel finger brace for preventing finger stiffness after trauma or surgery: a preliminary report with a case series

Purpose: Finger stiffness is a common complication following hand trauma or surgery. Early finger range-of-motion (ROM) exercises have proven to be the most effective method for preventing finger stiffness. In this paper, we introduce a novel finger brace designed for safe and early active exercises and present preliminary results from a small case series.Methods: Our innovative brace is designed for direct insertion into the finger, ensuring enhanced comfort during use. This brace features hinges that facilitate unrestricted movement in the proximal and distal interphalangeal joints, with each phalangeal component having a rounded shape to prevent rotation. Furthermore, grooves are integrated at the top of the phalangeal components for inserting bars; a straight bar to immobilize and a silicone band to provide elastic resistance exercises within a limited range.Results: Among 26 patients, 17 presented with fractures, five had extensor tendon injuries, and three had dislocations. For patients not requiring surgery, we applied the brace as early as possible. In cases involving surgery, the brace was applied step by step. When fixation was necessary for the first time, a straight bar was applied, and when starting finger movement, a silicone band was applied. The silicone band was then released to allow free finger movement. Except for one patient necessitating extensor tendon reconstruction due to a neglected rupture, all patients achieved full ROM without any complications.Conclusion: Our novel ROM finger brace represents a safe and user-friendly option for effectively initiating finger ROM exercises.

Early Results of First Metatarsophalangeal Joint Replacement Using the ToeFit-Plus™ Prosthesis

The aim of the present study was to investigate the outcomes of first metatarsophalangeal replacement for hallux rigidus using the Smith & Nephew ToeFit-Plus™ implant. We assessed the outcomes of 69 first metatarsophalangeal joint replacements using the American Orthopaedic Foot and Ankle Society score preoperatively and annually postoperatively, with retrospective radiologic review. All operations were performed by the same surgeon within 2 centers. A total of 69 arthroplasties were performed within the study period (57 patients). The median American Orthopaedic Foot and Ankle Society score at 1 year was 100 (interquartile range 100 to 100), at 2 years was 100 (interquartile range 95 to 100), at 3 years was 100 (interquartile range 87.5 to 100), and at 4 years, it was 100 (interquartile range 91.25 to 100). Radiolucencies around the phalangeal component were seen in 23 cases; however, this was symptomatic in only 2 patients, who required revision surgery. Our early results have shown that first metatarsophalangeal joint replacement surgery with the ToeFit-Plus™ prosthesis results in significant improvements in the American Orthopaedic Foot and Ankle Society scores for most patients; however, longer term follow-up is required to monitor the clinical effect of radiolucency around the phalangeal component.

Pyrocarbon metacarpophalangeal joint replacement in primary osteoarthritis

The purpose of this retrospective cohort study was to evaluate the outcomes of 18 primary pyrocarbon metacarpophalangeal joint replacements in 10 patients, performed for primary osteoarthritis. The mean age at operation was 66 years and mean follow-up was 58.6 months. The arc of motion improved from a mean of 30° to 40° and the mean QuickDASH score improved from 35 to 17. All except one patient were satisfied with their outcomes. Radiographically, there has been no evidence of dislocation or overt loosening, although there has been subsidence of some components up to 5 mm. One index finger implant was revised to a silastic implant for perceived alteration of precision pinch. Other complications included one intra-operative fracture that united and an asymptomatic stem fracture of one proximal phalangeal component. We continue to use the implant and aim to review our experience in a further 5 years.

Biomechanical Comparison of Metatarsal Head Designs in First Metatarsophalangeal Joint Arthroplasty

Arthritis of the metatarsophalangeal (MTP) joint is characterized by loss of MTP joint range of motion (ROM) and pain. Joint arthroplasty is one treatment option, and while results can be satisfactory, there is still room for improvement. The aim was to use cadaveric model to compare the sagittal kinematics and articulating contact properties of 4 different first metatarsal head designs of an MTP joint implant. Six cadaveric feet were each prepared with a single modular first MTP joint total arthroplasty. A standard cyclic load, which induced hallux dorsiflexion, was applied and motion measured from high resolution images. Contact behavior was collected simultaneously using a pressure transducer. Data collected compared the native joint with 4 different reconstructed cases. Each reconstructed joint used a different metatarsal-head-component while reusing the same phalangeal component to compare the 4 alternative metatarsal head designs. All reconstructed joints displayed greater ROM compared with the intact joint. Of the 4 metatarsal head components, the grooved, anatomical design demonstrated the greatest dorsiflexion when compared to the standard design, 31.6 degrees (SD ± 8.6 degrees), P < .05. All reconstructed joints displayed contact areas lower than the intact (~50%, P < .001). The grooved metatarsal-head-component experienced the least contact force (P < .015), and the eccentric component underwent the greatest contact pressure (P < .05) when compared to the intact case. In this study of a first metatarsophalangeal joint replacement design, ROM was shown to be better for the more anatomically designed metatarsal head, while contact properties did not vary across different designs. This information may be useful in the development of new metatarsal components.

Analysis of the in-vivo failure of the adhesive interlayer for a DLC coated articulating metatarsophalangeal joint

Unwanted physiological reactions, caused by particle release in articulating joints, are still a major concern in total hip arthroplasty. Diamond-like carbon coatings (DLC) show very low wear values in many technical applications. Attempts to transfer these outstanding tribological properties to in-vivo load bearing articulating joints turned out to be extremely problematic. A DLC coated metallic metatarsophalangeal (MTP) prosthesis, with both articulating surfaces coated, was explanted after approximately 4years. The DLC-coating was removed from the entire face of the phalangeal component and from most of the face of the metatarsal component. It appeared that the coating was scratched and then delaminated parallel to the scratches.To retrospectively investigate the reason for the in-vivo failure, the explanted prosthesis was analyzed by X-ray photoelectron spectroscopy (XPS) depth profiling and cross sectional scanning electron microscope (SEM) analysis. The coating consisted of an approximately 180nm thick DLC film and a circa 120nm thick silicon based adhesion promoting interlayer on a CoCrMo base material. SEM observation of transversal cuts showed that the delamination of the DLC-coatings was mainly caused by a slow in-vivo corrosion of the whole Si interlayer due to crevice corrosion. Additionally, a weak mechanical bond between the CoCrMo substrate and the Si-based interlayer further facilitated the access of body liquid below the Si interlayer. The instability of Si toward crevice corrosion was also demonstrated by a separate crevice experiment using silicon single crystals.

Mid-term Results of the MOJE Hallux MP Joint Replacement

There are reports of good early results in small numbers of patients implanted with the 'Moje' ceramic prosthesis. Published evidence thus far involves only small groups of patients with short-term followup. The purpose of this prospective study was to evaluate the emerging mid-term clinical and radiographic results from our center. We describe our single-surgeon experience of 63 components in 48 patients at a mean followup of 44 months. Patient satisfaction was assessed by questionnaire and radiographic assessment performed immediately post operatively and at the latest followup. Mean American Orthopaedic Foot and Ankle Society (AOFAS) Hallux score increased from 56 to 72 (p < 0.01) and mean satisfaction score was 7.6 (scale 1-10). Sixty-seven percent reported minimal or no pain. Five implants have been removed (8%), four because of pain associated with implant loosening and subsidence, and one because of deep infection. Fifty-seven percent of metatarsal and 56% of phalangeal components had subsided and we found radiographic evidence of loosening in 58% of X-rays analyzed at latest followup. Prosthetic subsidence was associated with greater margin of uncovered bone under the prosthesis (p = 0.05 for metatarsal, p = 0.03 for proximal phalanx component) and longer followup (p < 0.001). In spite of the good clinical outcome at the mid-term stage with 91% implant survival, given the widespread loosening and subsidence encountered in our study, the long-term outcome following this procedure is uncertain.

Wear testing of a DJOA finger prosthesis in vitro

Although the market for replacement of diseased metacarpophalangeal (MCP) joints is dominated by single-piece silicone prostheses, several two-piece designs have been implanted. One such is the Digital Joint Operative Arthroplasty (DJOA) which consists of a part-spherical stainless steel metacarpal component which articulates within a matching concave phalangeal component made of ultra high molecular weight polyethylene (UHMWPE). A DJOA MCP prosthesis was tested using a clinically-validated finger simulator while a second DJOA prosthesis acted as a statically-loaded soak-control. Testing ran to 7.1 million cycles of flexion-extension. It was found that the UHMWPE components, both test and control, gained in weight by a similar amount. Therefore apparently there was no wear of the test components. However, the initial and final surface finish values of the test stainless steel metacarpal head were relatively high. Calculations based on this roughness data, plus recent dynamically-loaded soak data, may explain the apparent lack of wear.

Investigating the potential advantages of a new design metacarpophalangeal joint

This paper investigates a new metacarpophalangeal joint design aimed at treating patients with moderate to severe forms of arthritis affecting the index, long, ring, and little fingers. Current small joint arthroplasty designs, including those for the metacarpophalangeal joint of the hand, have had limited success owing to mechanical failures and can be divided into two main families: single-piece elastomer implants and surface articulating implants. The design proposed in this study involves combining the principles of a surface weight-bearing articulating implant with those of a spanning elastomeric implant. The design consists of metacarpal and proximal phalangeal articulating housings and a central flexible spanning elastomer rod that maintains the alignment of the metacarpal and proximal phalangeal components. A preliminary finite element analysis was used to investigate the stresses in the design, the wear of the articulating bearing surfaces for different material combinations, and the stresses between the central elastomer rod and the articulating housings. This preliminary analysis shows that the design should withstand the probable loading conditions experienced within the human body and that the wear rates of the articulating surfaces and the central elastomer are acceptable.

TOEFIT-PLUS™ replacement of the first metatarsophalangeal joint of the first toe: A short-term follow-up study

Osteoarthritis of the metatarsophalangeal joint is normally treated with arthrodesis or resection arthroplasty. Metallic replacement of these joints is sometimes used but is not widely accepted. The use of silastic joints is associated with synovitis and implant failure. In this study, our goal was to measure and evaluate the results of metatarsophalangeal replacement with TOEFIT-PLUS™ (Plus Orthopedics AG, Switzerland) arthroplasty. The implant consists of metatarsal and phalangeal components with polyethylene inserts. We prospectively recruited 20 patients (13 female, 7 male) with an average age of 57 years. Mean follow-up time was 12.2 months (S.D. 5.4, range of 6–21 months). Criteria for the selection of joint replacement were mainly pain, loss of motion, and radiological changes. Clinical assessment was based on the MTP-interphalangeal score of the American Orthopaedic Foot and Ankle Society (AOFAS). Twenty cases of arthritis of the metatarsophalangeal joints were treated surgically with TOEFIT-PLUS™ replacement of the joint. All patients had release of the soft tissue on the plantar side. Short-term follow-up of average 12 months showed good improvement in clinical symptoms (pain and function), improvement in foot scores, and 90% patient-reported satisfaction with the operative results. Range of motion was average 16.35° of plantar flexion and 16.05° of dorsiflexion. A longer follow-up period is required to gauge the long-term survivorship of the TOEFIT-PLUS™ system.

Surface Replacement Arthroplasty of the Proximal Interphalangeal Joint

The first proximal interphalangeal joint (PIPJ) replacements were hinged devices with single-axis motion. Newer implant arthroplasties of the PIPJ have anatomically designed proximal phalangeal and middle phalangeal components. A need to create balanced forces across the joint was the rationale for the semiconstrained PIPJ prosthesis, which uses an anatomic design. These low-profile implants limit bone excision while preserving the integrity of the collateral ligaments. Paramount in the success of this implant is maintaining the integrity of the insertion of the central slip as it inserts on the base of the middle phalanx. The proximal and middle phalanx should be broached such that the largest implant can be press-fit in place. Greater stability is gained with a collateral ligament-preserving implant. Patient selection should include those patients with sufficient soft-tissue integrity. In general, patients with inflammatory disorders, collateral ligament insufficiency, and acute or chronic PIPJ septic arthritis are poor candidates for PIPJ surface replacement arthroplasty.

Examination of failed ex vivo metal-on-metal metatarsophalangeal prosthesis and comparison with theoretically determined lubrication regimes

Replacement of the first metatarsophalangeal (MTP) joint is a relatively uncommon procedure compared with hip and knee arthroplasty. A cobalt chrome-on-cobalt chrome MTP prosthesis, which had a diamond-like carbon (DLC) coating applied to its articulating faces, was obtained for ex vivo analysis. By modelling the ball and socket implant as an equivalent ball-on-plane model and employing elastohydrodynamic theory, the predicted lubrication regimes applicable to this implant design were determined. These calculations were undertaken for a 10–1500 N range of loading values and a 0–30 mm/s range of entraining velocities, for both worn and unworn situations. Calculations showed that the implant would almost always operate in the boundary lubrication regime. The presence of scratches on the articulating faces of the ex vivo sample further implied boundary lubrication. The DLC coating had been removed from the entire face of the phalangeal component and from most of the face of the metatarsal component. From the latter it appeared as if the coating had been scratched and then flaked away parallel to the scratches. In turn this suggested a corrosion based failure of the interface between the DLC coating and the cobalt chrome subsurface.

Arthrodesis or Total Replacement Arthroplasty for Hallux Rigidus: A Randomized Controlled Trial

Arthrodesis is the current treatment for end-stage hallux rigidus, although there are many reports advocating total joint replacement arthroplasty. The aim of this randomized controlled trial was to evaluate clinical outcomes after first metatarsophalangeal joint (MTPJ) arthrodesis and replacement arthroplasty. Between November, 1998, and January 2001, 63 patients between the ages of 34 and 77 years, with unilateral or bilateral MTPJ arthritis were recruited and randomly selected to have either MTPJ arthrodesis or arthroplasty. Twenty-two patients (38 toes) had arthrodesis and 27 patients (39 toes) had arthroplasty. A single surgeon performed all surgery. The primary outcome measure determining successful surgery was a decrease in pain as measured on a Visual Analogue Scale (VAS). Functional outcome was assessed at 6 months and 1 and 2 years. Cost data were simultaneously collected. At 24 months, pain improved in both groups (p < 0.001), but there were significantly greater improvements after arthrodesis (p = 0.01). All 38 arthrodeses united at a mean dorsiflexion angle of 26 degrees, with few complications. In contrast, in the arthroplasty group, six of the 39 inserted implants had to be removed because of phalangeal component loosening. In the remainder the range of motion gained was poor, and the patients tended to bear weight on the outer border of their foot. The cost ratio was 2:1 in favor of arthrodesis. Outcomes after arthrodesis were better than those after arthroplasty. The results were partially attributable to an unacceptably high incidence of loosening of the phalangeal components, which resulted in removal of the implants. However, even when data from the failures were excluded, arthrodesis was clearly preferred by most patients.

Ergebnisse nach Arthroplastik der Fingergrundgelenke mittels zementfreier, ungekoppelter HM-Prothese beim Rheumatiker

In 80 % of patients with rheumatoid arthritis, the metacarpophalangeal (MP) joints are involved with increasing destruction and loss of function. Silicone arthroplasty of the MP joints leads to a limited range of motion, an increase in osteolysis and fractures of the implants. The cementless, unconstrained design of the HM prosthesis is a new concept for replacing the MP joints of rheumatoid patients. Short-term and midterm results are shown. In a prospective study, 38 HM prostheses were implanted, 28 in patients with rheumatoid arthritis, four with osteoarthrosis, five with polyarthrosis and one after revision of a silicone implant. The patients were reexamined clinically and radiologically after an average follow-up of 16 months (6 - 37 months). The average active range of motion for extension, flexion increased from 0/15/65 degrees before surgery to 0/9/65 degrees after surgery. The remaining ulnar drift was 12 degrees (preoperative 18 degrees ). The average grip strength after surgery was 80 % of the opposite side. Pain in the verbal analog scale improved from 2.3 to 1.7 postoperatively. One palmar subluxation of an implant of the little finger was recognized. No infection occurred. The X-rays showed complete osteointegration in all metacarpal components. Radiolucent zones were found in progress only at the basis on the phalangeal components without radiological signs of loosening or sinking. The short- and midterm results after implantation of the cementless, unconstrained HM prosthesis show an improved hand function and pain relief. The design of the implant may solve the accepted postoperative problem of instability of the MP joints. Until now, no prosthesis had to be exchanged.

MTP Prosthesis (ReFlexion™) for Hallux Rigidus

ABSTRACT Severe osteoarthritis of the first metatarsophalangeal joint is classically treated with an arthrodeses or a resection arthroplasty. Although endoprostheses for the first metatarsophalangeal joint had been introduced 50 years ago, they have not reached wide acceptance yet. The use of silicone spacers with their encouraging early results have been markedly decreased after the side effects (bony cyst, synovitis, implant failure) occurred. Since then, several attempts have been made to design total metatarsophalangeal joint replacements. The ReFlexion™ prosthesis, for example, consists of 3 components: a metatarsal stem, a phalangeal stem, and a metatarsal head. All components are interchangeable and available in 3 sizes. Due to the quality of the cancellous bone, the components can be inserted with or without cement. Because the surgical technique is guided by an appropriate instrumentation device to facilitate positioning of the implants, the release of the plantar capsule, including a debridement of the sesamoids, seems to be more demanding. Data from our prospective mid-term study (follow-up 39 months) revealed encouraging results for pain relief and range of motion. According to the score of the American Orthopaedic Foot & Ankle Society, the results improved from 51 points preoperatively to 74 points postoperatively. Assessing the radiographs, we observed radiolucent lines in 25% of the phalangeal components and in 10% of the metatarsal components. These findings were mainly attributed to a cemented fixation technique and did not impair the clinical results. Although we had mainly operated on hallux rigidus deformities, we observed multiplanar malalignment (60.5%) after the operation, including slight hallux valgus or hallux varus and plantar subluxation of the proximal phalanx. With regard to the relief of pain and the functional impairment, further attempts should been made to improve implant properties, that is, fixation to the bone, resurfacing of the plantar metatarsal aspect, and a semiconstrained design to stabilize the joint in the transverse plane.

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

An unconstrained surface metacarpophalangeal joint replacement was developed with metal metacarpal and polyethylene phalangeal components, fixed by uncemented finned polyethylene plugs which allowed some metacarpal component motion. Clinical and radiological results in 13 joints in eight patients are presented after 5 years. One infection required revision at 3 months. There were no further complications. At final review there were no implant failures. Two of 13 joints showed lucency around the phalangeal component and one showed 2 mm subsidence of the metacarpal component. No other adverse radiological features were observed. Seven patients had no pain and one had minor discomfort. Joint movement had improved from an arc of 27° to 60° and disability, assessed using the P.E.M. questionnaire, had improved from 77% to 9%.

Non-constrained titanium-polyethylene total endoprosthesis in the treatment of hallux rigidus. A prospective clinical 2-year follow-up study.

To evaluate the outcome in a prospective 2-year follow-up study of a non-constrained titanium-polyethylene total endoprosthesis (ReFlexion) in the treatment of hallux rigidus. Ten patients with painful hallux rigidus were treated with a non-constrained titanium-polyethylene total endoprosthesis (ReFlexion). The American Orthopaedic Foot and Ankle Society (AOFAS) scoring was used preoperatively and at follow-up. At 2-year follow-up, the AOFAS scoring shbwed 5 instances of excellent, 1 of good, 2 of fair, and 2 of poor outcome. Eight patient were subjectively satisfied and 2 dissatisfied. Five of the patients were painless, 4 had mild, occasional pain, and 1 had moderate, daily pain in the first metatarsophalangeal joint. The mean VAS was 7.6 (SD 2.0) preoperatively and 1.1 (SD 1.4) at 2-year follow-up (p < 0.001). Extension increased by a mean of 25 (13-38) degrees and flexion by a mean of 15 (2-35) degrees (p < 0.001). Eight patients had no activity limitations, while 1 had mild and 1 moderate limitations. Alignment of the metatarsophalangeal joint was good in 7 cases, but some degree of valgus malalignment was seen in 2 and symptomatic malalignment in 1. Complications included one subluxation of a prosthesis, one recurrence of severe valgus alignment and one superficial wound infection. Radiological loosening of one cementless phalangeal component was seen at follow-up. The non-constrained titanium-polyethylene total arthroplasty gave satisfactory 2-year outcome in 60% of the patients. It is an alternative treatment for hallux rigidus in low demand patients. We do not recommended it for athletes and young people, because high forces acting on the prosthesis may cause a failure.

Phalangeal fusion in schizotheriine Chalicotheres (Mammalia, Perissodactyla)

In four genera of schizotheriine Chalicotheriidae—Moropus, Tylocephalonyx, Phyllotillon,andAncylotherium–proximal and middle phalanges of digit II of the manus fuse to form a duplex bone. Fusion of proximal and middle phalanges of digit II of the pes also occurs in many species of these genera. Radiographic and sagittal-sectional study of the fused duplex phalanges ofMoropus elatusandTylocephalonyx skinnerishows that the joint between the two bones formed fully prior to fusion but had little movement. Fusion proceeded by external enthesial interactions at the insertion of the ligament capsule and by disruption of cortical bone with trabecular bridging along the internal part of the original articular surface. Cortical disruption is more rapid on the middle than on the proximal phalangeal component of the duplex. InM. elatus,the degrees of external and internal fusion roughly correspond, and a ventral surficial groove sometimes traces the former facet, whereas inT. skinneriexternal fusion is much more developed than internal fusion. Phalangeal fusion seems to have strengthened the digit against strong forces applied along the medial (radial or tibial) side of the foot.

Schultz metacarpophalangeal arthroplasty: A long-term follow-up study

We describe a prospective, long-term evaluation of the Schultz metacarpophalangeal joint implant. The prosthesis is a semiconstrained, cemented implant with a ball-in-socket articulation. Thirty-six implants were followed for an average of 10.9 years. There was a progressive decrease in range of motion and strength and a recurrence of ulnar deviation. The neck of the proximal phalangeal component fractured in 39% of the joints. Periarticular heterotopic bone formed in all joints, but was extensive in only 22%. Although some lucency of the bone-cement interface was seen in 80% of the joints, no prosthetic loosening occurred in this series. Our results indicate that long-term, intramedullary cement fixation of relatively long-stemmed components can be satisfactory. However, the articulated portion of this implant does not consistently withstand the stresses transmitted across the joint and does not provide long-term joint stability.