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Arthroplasty of the small joints of the hand and fingers is a complex problem facing the hand surgeon. Pyrocarbon implants have been available for several decades. They were originally thought to provide better functional outcomes than silicone implants in patients, mostly due to recreation of the joint anatomy. In a recent publication, pyrocarbon proximal interphalangeal joint (PIPJ) arthroplasty was found to have a higher complication and revision rate. We present a patient with pyrocarbon metallosis of the PIPJ in a revision arthroplasty procedure. Level of Evidence: Level V (Therapeutic) [ABSTRACT FROM AUTHOR]

A change in the structure of the pyrolytic carbon coating deposited on the surface of a graphite substrate was shown depending on the time the substrate remained in the reaction zone. A multilayer spherical structure of the pyrolytic carbon has been revealed; according to experimental data, is formed on a layer of already formed pyrolytic carbon. A mechanism for the formation of a multilayer spherical structure is proposed. [ABSTRACT FROM AUTHOR]

Background: In late Kienbӧck's, the lunate is fully fragmented and nonreconstructible. Replacing the lunate with a pyrocarbon prosthesis preserves load distribution and avoids carpectomy or fusion, but leaves the wrist intrinsically unstable, requiring additional soft-tissue stabilization techniques. Methods: Five men and 7 women with a mean age of 43 (±15) years underwent prosthetic replacement of the lunate with dual bundle scaphoid-triquetrum tenodesis for carpal stabilization. The mean follow-up interval from initial surgery was 9.1 (±1.7) years. Outcomes were Disabilities of Arm, Shoulder, and Hand (DASH) score, revision or conversion surgery, and wrist range of motion. Results: The mean DASH score was 8.9 (±7.1). No patients reported any additional revision or conversion surgery. The mean wrist flexion was 60° (±14°); wrist extension was 45° (±21°). Conclusions: Clinical outcomes proved more favorable than anticipated, particularly the self-rated outcomes scores and the absence of any revision or conversion surgery. [ABSTRACT FROM AUTHOR]

The objective of this study was to analyze postoperative outcomes in a group of patients who underwent metacarpophalangeal (MCP) arthroplasty using a pyrocarbon prosthesis for noninflammatory arthritis. An analysis of 44 MCP joint arthroplasties in 30 patients with >2 years of follow-up over a 12-year period was reviewed. The mean age was 63 years. The primary operative indication was pain and stiffness from osteoarthritis refractory to nonsurgical management. At a mean follow-up of 6 ± 3 years, 8 (18%) joints underwent reoperation, including 5 (11%) that underwent revision arthroplasty. The 2- and 5-year rates for survival free of revision arthroplasty were 95% and 93%, respectively. One (2%) operation was complicated by intraoperative fracture. Postoperative complications occurred in 8 (18%) fingers and included ligament/tendon rupture (n = 3) and instability (n = 2). There was significant postoperative improvement in pain levels, MCP arc of motion, pinch strength, and grip strength. At a mean 5 years of radiographic follow-up, 7% had progressive implant instability because of grade 3 or greater loosening. No joints experienced implant instability from progressive subsidence. Metacarpophalangeal arthroplasty using a pyrocarbon implant for osteoarthritis demonstrates an 7% revision rate at 5 years after surgery. Complications lead to reoperation in 1 of 5 arthroplasties. Radiographic evidence of implant instability was uncommon. Overall, patients experienced predictable pain relief and improvements in their range of motion and pinch strength. Therapeutic IV. [ABSTRACT FROM AUTHOR]

The possibility of utilizing technical pyrocarbon, produced by the pyrolysis of used automobile tires, in a composite suspension fuel is demonstrated. It has been found that pyrocarbon-based systems without additives are not suitable for use as fuel due to thickening and hydrophobic properties. To improve the properties of the composite suspension fuels, the influence of stabilizer, plasticizer, and dispersant additives on the rheological properties of the composite suspension fuel was investigated. Carboxymethyl cellulose, sodium lignosulfonate, NF, C-3 (a condensation product of β-naphthalene sulfonic acid and formaldehyde), and humic acids were used as additives. It was determined that the surface of unmodified pyrocarbon has a positive surface charge in the pH range of 2-10. Addition of reagents induces a change in the surface charge of pyrocarbon and surface recharging. It is shown that the best results in composite suspension fuel compositions are achieved with the addition of C-3 at a concentration of 2 wt.%. The effective viscosity of the obtained suspensions at a shear rate of 9 s-1 does not exceed 0.8 Pa⋅s. This allows the use of the obtained systems with additives as liquid suspension fuels. [ABSTRACT FROM AUTHOR]

The purpose of this study was to review two surgeons' medium-term results with the Ascension Pyrotitan surface replacement and the Pyrocarbon hemiarthroplasty. We hypothesized they would provide good medium-term outcomes with no significant difference between the two implants. The first 21 implants were surface replacements and the subsequent 58 hemiarthroplasties making a total of 79. Overall, the minimum follow-up was two years and maximum nine years and nine months (average = five years and six months). The average follow-up for the Ascension Pyrotitan was eight years and two months and Pyrocarbon hemiarthroplasty was five years and two months. Survivorship, Oxford, and Subjective Shoulder Value (SSV) scores, and incidence of squeaking were recorded. The average age at implantation was 57.7 years (range 20-80). Thirty-five were female and 44 male. The indication for surgery was osteoarthritis in 56 patients, post instability in 10 patients, post fracture in 7 patients, avascular necrosis in 4 patients, synovial osteochondromatosis in one, and rheumatoid arthritis in one. Of the 79 patients in the cohort, five were deceased, two were revised to reverse for cuff failure, one was revised for Cutibacterium acnes infection, and one was revised to Pyrocarbon hemiarthroplasty for fracture of a Pyrotitan surface replacement. This left 70 patients, all of whom were included in this review. Survivorship at final follow-up for the Pyrotitan surface replacement was 88.9% and Pyrocarbon hemiarthroplasty was 96.4%. The average SSV for all patients reviewed was 86%, the Ascension Pyrotitan patients scoring 87% and the Pyrocarbon hemiarthroplasty scoring 86%. The average Oxford score for the whole cohort was 42 out of a maximum of 48, with Ascension Pyrotitan scoring 42.3 and Pyrocarbon hemiarthroplasty 41.9. Recent Oxford score for the postinstability group was 44, osteoarthritis 42.6, postfracture 39.5, and 35 for avascular necrosis (not statistically significant). Fourteen of 70 patients reported squeaking (20%), 4 daily, 5 weekly, and 5 monthly. Average Oxford score in those who experienced squeaking was 39 compared with nonsqueakers at 43 (P =.02). Correlation between Oxford score and SSV was high with a correlation coefficient of 0.79. The Oxford score for the Pyrotitan at 42.3 was significantly better than the New Zealand Joint Registry score for the Global Cap at 34.5 (P =.001) and the Pyrocarbon hemiarthroplasty at 41.9 significantly better than the Aequalis CoCr hemiarthroplasty at 36.8 (P =.005) Pyrocarbon looks to be a durable bearing surface and a good option for the younger osteoarthritic patient where risk of glenoid component failure is high. [ABSTRACT FROM AUTHOR]

Kienbock disease, or avascular necrosis of the lunate, is an uncommon cause of a painful and stiff wrist. Management options range from conservative treatment in the form of immobilization and corticosteroid injections to a wide variety of surgical treatments that depend on the structural integrity of the lunate, intercarpal relationships, and the condition of the articular cartilage of the wrist. A particularly difficult problem lies in the management of young patient in whom vascularized bone grafting of the lunate has failed but in whom arthritis has not yet developed. Pyrocarbon lunate implant arthroplasty is a newer treatment option for such a patient, and allows the preservation of the remainder of the proximal carpal row while directly addressing the degenerative lunate. This article describes the evidence and surgical technique for lunate implant arthroplasty and presents an illustrative case example. [ABSTRACT FROM AUTHOR]

Hemishoulder arthroplasty (HSA) is a more conservative alternative to total shoulder arthroplasty for young and active patients with minimal glenoid erosion or deformity. Pyrocarbon humeral heads were introduced as an alternative to metallic humeral heads, which were associated with glenoid erosion in 28%-43%. The purpose of this study was to evaluate the progression of glenoid erosion and clinical scores of HSA using pyrocarbon humeral heads from short- (2-4 years) to midterm (5-9 years). We retrieved the records of 45 consecutive patients who underwent HSA with pyrocarbon humeral heads from 2013 to 2017. Patients were evaluated radiographically and clinically at a first follow-up (2-4 years) and a second follow-up (5-9 years). Preoperative glenoid morphology was assessed using computed tomography scans, and glenoid erosion was assessed using plain radiographs according to Sperling et al. The Constant score (CS), American Shoulder and Elbow Surgeons (ASES) score, and Subjective Shoulder Value (SSV) score were assessed by an independent observer. From the initial cohort of 45 patients, 2 underwent revision surgery (4.4%) due to persistent pain (without signs of rotator cuff pathology or glenoid erosion) and 6 were lost to follow-up (13%), leaving 37 for outcome assessment (82%). At the first follow-up of 2.2 ± 0.4 years, all clinical scores improved substantially (CS from 29.3 ± 13.5 to 76.7 ± 14.4, ASES from 23.7 ± 15.6 to 87.0 ± 16.0, and SSV from 25.3 ± 12.2 to 84.1 ± 15.2), and at the second follow-up of 6.2 ± 1.2 years, good clinical scores were maintained (CS from 76.7 ± 14.4 to 80.8 ± 16.0, ASES from 87.0 ± 16.0 to 92.3 ± 15.0, and SSV from 84.1 ± 15.2 to 82.8 ± 18.3). At the second follow-up, glenoid erosion was moderate in 9 (24%) and severe in 3 (8.1%). When comparing with immediate postoperative radiographs, 10 shoulders exhibited progression of glenoid erosion by 1 grade (n = 9) or 2 grades (n = 1). Pyrocarbon humeral heads for HSA grant satisfactory clinical scores with minimal glenoid erosion. [ABSTRACT FROM AUTHOR]

The success of traditional shoulder hemiarthroplasty (HA) with cobalt-chromium heads is limited by painful glenoid erosion with problematic bone loss. Hemiprostheses with pyrolytic carbon (PyC) heads have shown reduced glenoid erosion in experimental laboratory studies. Few in vivo data are available. We performed a single-center consecutive cohort study of 31 of 34 patients (91%) who underwent PyC HA between September 2013 and June 2018. In 11 of these patients, concentric glenoid reaming was additionally performed. The mean follow-up period was 5.5 years (range, 3.5-7 years). Standardized radiographs were taken, and clinical function (Constant score) and pain (visual analog scale score) were recorded. Anteroposterior radiographs were analyzed according to an established method by 2 independent observers: A line parallel to the superior and inferior glenoid rim was translated to the most medial point of the glenoid surface. A further parallel line was placed on the spinoglenoid notch. The distance between these 2 lines was measured. Measurements were scaled using the known diameter of the implanted humeral head component. To assess eccentric erosion, anteroposterior and axial images were classified according to Favard and Walch, respectively. Mean medial glenoid erosion measured 1.4 mm at an average of 5.5 years of follow-up. In the first year, 0.8 mm of erosion was observed, significantly more than the average erosion per year of 0.3 mm (P <.001). Mean erosion per year was 0.4 mm in patients with glenoid reaming vs. 0.2 mm in those without reaming (P =.09). An evolution of glenoid morphology was observed in 6 patients, of whom 4 had a progression of the erosion grade. The prosthesis survival rate was 100%. The Constant score improved from 45.0 preoperatively to 78.0 at 2-3 years postoperatively and 78.8 at latest follow-up (5.5 years postoperatively) (P <.001). The pain score on a visual analog scale decreased from 6.7 (range, 3-9) preoperatively to 2.2 (range, 0-8) at latest follow-up (P <.001). There was a weak correlation (r = 0.37) between erosion and pain improvement (P =.039) and no correlation between erosion and change in Constant score (r = 0.06). PyC HA caused little glenoid erosion and a sustained improvement in clinical function in our cohort at mid-term follow-up. PyC demonstrates a biphasic development of glenoid erosion, with a reduced rate after the first year. PyC HA should therefore be considered as an alternative to cobalt-chromium HA and to anatomical total shoulder arthroplasty for patients with a high risk of glenoid component complications. [ABSTRACT FROM AUTHOR]

The history of joint replacement can be framed as a battle to reduce wear. Pyrocarbon has been shown to be a low wear material, but can low wear against an ultra high molecular weight polyethylene (UHMWPE) counterface be achieved? To investigate this research question, a 50-station, clinically validated wear screening machine was used. Half the stations tested UHMWPE pins against pyrocarbon discs, and half the stations tested UHMWPE pins against cobalt chromium (CoCr) discs. The test rig ran at 1Hz, the nominal contact stress was 2.07 MPa, and testing ran to 5 million cycles. A biomimetic lubricant was used, it was replaced every 500,000 cycles. At the end of testing, the UHMWPE pins rubbing against pyrocarbon discs had a statistically significant reduced wear, compared with the UHMWPE pins rubbing against CoCr discs (p ≤ 0.01). Analysis of the discs at the end of testing showed greater adherence of phospholipids on the pyrocarbon discs than the CoCr discs. In turn, it was also seen that far less UHMWPE was attached to the pyrocarbon discs than to the CoCr discs. Based on this evidence, it is suggested that pyrocarbon surfaces are associated with reduced adhesive wear of UHMWPE compared with CoCr surfaces. In addition, at the end of testing, the CoCr discs were found to be significantly rougher than the pyrocarbon discs. Therefore, pyrocarbon maintained a smoother surface than CoCr, likely meaning that abrasive wear of UHMWPE was reduced compared with CoCr. [Display omitted] • Less wear (p < 0.01) of UHMWPE against pyrocarbon than against CoCr after 5 mill cycles • At end of test, greater adhesive wear of UHMWPE on CoCr counterfaces than pyrocarbon • CoCr counterfaces rougher than pyrocarbon, so greater abrasive wear likely [ABSTRACT FROM AUTHOR]

Purpose: To assess the clinical and radiographic outcomes, at a minimum follow-up of 4 years, following HSA using pyrocarbon in patients that had prior open Latarjet., Methods: The authors retrieved the records of 61 consecutive patients that underwent HSA with a pyrocarbon humeral head at 2 centers between December 2013 and October 2019. Eight patients (9 shoulders) had undergone previous Latarjet procedures without other surgical antecedents. Patients underwent radiological assessment, and clinical assessment including Constant score, Subjective Shoulder Value (SSV), and pain on VAS. Finally, range of motion was assessed, including active forward elevation and external rotation., Results: The initial cohort of 9 shoulders, comprised 1 woman and 7 men (1 bilateral), aged 52.5 ± 5.2 at their index HSA, which was performed 27.7 ± 9.3 years following their prior Latarjet procedure. One shoulder required conversion to reverse shoulder arthroplasty, 3 years after HSA. The remaining 8 shoulders were assessed at 6.1 ± 1.6 years (range, 4-8) after the index HSA. Glenoid erosion only progressed in 1 shoulder from mild to moderate. The Constant score was 79.6 ± 12.7, pain on VAS was 1.0 ± 2.1, and SSV was 80.0 ± 25.6. The active forward elevation improved from 96°±41° to 151°±29°, and external rotation from 11°±17° to 32°±8°., Conclusion: Patients that underwent HSA using pyrocarbon heads following prior Latarjet had satisfactory clinical scores, and glenoid erosion only progressed in 1 patient. Furthermore, only 1 patient required conversion to RSA. The clinical relevance is that HSA using pyrocarbon heads is a safe treatment and grants satisfactory clinical outcomes in patients with prior Latarjet., Level of Evidence: Level III, retrospective comparative study., Competing Interests: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2024.)

Aiming to build a tissue analogue engineered cartilage from differentiated chondrocytes, we investigated the potential of a pyrocarbon (PyC)-based and scaffold-free process, under mechanical stimulation. PyC biomaterial has shown promise in arthroplasty and implant strategies, and mechanical stimulation is recognized as an improvement in regeneration strategies. The objective was to maintain the cell phenotype to produce constructs with cartilage-like matrix composition and mechanical properties. Primary murine chondrocytes were deposited in drop form between two biomaterial surfaces expanded to 500 μm and a uniaxial cyclic compression was applied thanks to a handmade tribo-bioreactor (0.5 Hz, 100 μm of amplitude, 17 days). Histology and immunohistochemistry analysis showed that PyC biomaterial promoted expression of cartilage-like matrix components (glycosaminoglycans, type II collagen, aggrecan). Importantly, constructs obtained in dynamic conditions were denser and showed a cohesive and compact shape. The most promising condition was the combined use of PyC and dynamic stimulation, resulting in constructs of low elasticity and high viscosity, thus with an increased damping factor. We verified that no calcium deposits were detectable and that type X collagen was not expressed, suggesting that the cells had not undergone hypertrophic maturation. While most studies focus on the comparison of different biomaterials or on the effect of different mechanical stimuli separately, we demonstrated the value of combining the two approaches to get as close as possible to the biological and mechanical qualities of natural hyaline articular cartilage., (Copyright © 2024. Published by Elsevier B.V.)

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., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: This retrospective, observational study aimed to assess the revision rates and survival curves in total shoulder arthroplasty (TSA) and hemi-shoulder arthroplasty (HSA) patients, including a subanalysis to investigate the impact of a pyrocarbon humeral head in revision rates., Methods: Data collected from 7 surgeons who performed primary HSA in 92 patients and primary TSA in 508 patients at a large private clinic were analyzed. The study focused on revision rates and identified factors leading to revisions, including rotator cuff insufficiency, dislocation, aseptic loosening, implant material, and glenoid erosion., Results: The overall revision rate for HSA was found to be significantly higher (7.6%) than that for TSA (1.2%), with a maximum follow-up of 7 years. Subanalysis within the HSA group revealed a notably higher revision rate in cases involving a metal head (cobalt-chrome or titanium) (12.8%) than those with a pyrocarbon head (2.3%)., Conclusions: This study underscores the importance of distinguishing between TSA and HSA when evaluating shoulder arthroplasty outcomes. The significantly higher revision rate in HSA, particularly with metal heads, suggests the need for careful consideration of implant selection to optimize long-term success in shoulder arthroplasty procedures., (Copyright © 2024 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

The study investigated the morphology, microstructure, structure, texture, and mechanical properties of heat-treated at 1600 °C and 2000 °C pyrolytic carbon (PyC) deposited from methane using various methods such as scanning electron microscopy (SEM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), Raman spectroscopy, and ultrasonic dynamic measurements of Young's modulus. The PyC was synthesised at 1100 °C using a chemical vapour deposition (CVD) method with direct electrical heating of the two types of carbon fibres (CFs). The results showed that the PyC had a low- and medium-texture (LT and MT PyC). Analysis of the graphitization trajectory allowed the determination of structural changes in the material as a function of temperature, including the growth of crystallites and an increase in the crystallinity proportion without the significant rearrangement within PyC. The crystallite size and the number of interstitial defects has increased with temperature that controlled mechanical properties. Therefore, based on the results obtained, the most suitable composites for further research in the context of electrodes for stimulation of nervous tissue were obtained at the temperature of their synthesis, i.e. at 1100 °C. [Display omitted] • The matrix area distinguished low-textural (LT) and medium-textural (MT) PyC. • The surface can be significant during the deposition only of initial PyC layers. • Amorphous forms may evolve towards turbostratic ones. • Thermodynamically, the organising process may occur but is kinetically limited. • The mechanism of the graphitization trajectory was the formed domains growth. [ABSTRACT FROM AUTHOR]

Case: A 54-year-old male with osteoarthritis of the right long finger metacarpophalangeal joint underwent PyroCarbon joint arthroplasty. Seven years later the patient presented for metacarpophalangeal joint swelling and pain. The workup was benign, without signs of implant complication or osseous abnormality. He underwent washout and two-stage revision, where gross implant wear and debris not demonstrated by radiograph were found. He then returned to the operating room for reimplantation of a PyroCarbon implant., Conclusion: This case demonstrates a novel presentation of aseptic PyroCarbon implant failure in the hand without radiographic abnormality that can alter operative management by reducing operating room returns., (Copyright © 2024 SFCM. Published by Elsevier Masson SAS. All rights reserved.)

Introduction: Pyrocarbon promises to be an optimal material choice for radial head arthroplasty (RHA) due to an elastic modulus comparable to the radial diaphysis and thus providing higher biocompatibility. Primary objective was to determine the complications and revision rates related to the usage of these prostheses. The secondary objective was to assess the clinical and radiological outcomes of Pyrocarbon RHAs., Hypothesis: Pyrocarbon RHAs have good clinical and radiological outcomes with low complications and revisions., Methods: Ovid MEDLINE and Embase databases were used to search for studies on outcomes and complications of the RHAs using Pyrocarbon radial head prostheses. The systematic review was designed in accordance with the PRISMA guidelines and included studies were appraised using the MINORS tool. Complications and RHA revision rates were assessed. Functional outcomes were reviewed using PROMs (like MEPI, DASH and BMS), post-op range of motion (using goniometer) and grip strength (using the dynamometer). Postoperative radiological outcomes like peri-prosthetic lucency, radial neck osteolysis, radio-capitellar congruence, capitellar erosion, overstuffing/understuffing and osteoarthritis were reported using radiographs., Results: A total of 12 studies cumulatively reporting 353 patients who underwent Pyrocarbon RHAs were included in the review. The mean age of patients across the studies ranged from 47 to 54 years of which 50.5% were males. The majority of radial head replacements were done for acute trauma (87.5%) with the remainder done for arthritis (1.7%) and trauma sequelae (10.8%). Mean follow-up period in the selected studies ranged from 18 to 110 months with minimum follow-up across all studies being 12 months. Modular Pyrocarbon (MoPyC, Tornier™) was the implant of choice in ten studies while two studies used the Ascension Pyrocarbon radial head (Ascension Orthopaedics™). Ten studies demonstrated mean MEPI ranging from 75.5 to 96. Mean extension deficit ranged from 6 to 19 degrees, mean flexion from 120 to 140 degrees, mean pronation from 71 to 87 degrees and mean supination from 63 to 85 degrees. Relative grip strength ranged from 69 to 96% of the contralateral limb. Revisions due to implant-related reasons (intra-prosthetic dissociation, prosthetic fracture, peri-prosthetic loosening, radio-capitellar subluxation and understuffed/overstuffed elbow) was 6.8% (24/353). Radial stress shielding and peri-prosthetic lucency was reported in 10 to 100% of patients across different studies but symptomatic implant loosening leading to revision remained rare (2%, 7/353). Radio-capitellar congruence was reported in 81% to 100% cases while capitellar erosion ranged from 0% to 89%. Pyrocarbon implants specific complications included head-neck intra-prosthetic decoupling (1.1%) and pyrocarbon head fractures (0.9%). In total, 5.7% cases underwent re-surgery due to non-RHA related reasons., Discussion: The pyrocarbon RHA shows good functional outcome, range of motion and low revision rates. This aligns with the working hypothesis of this review. However, pyrocarbon radial head implants have implant-specific complications like pyrocarbon radial head fractures and intra-prosthetic decoupling between stem and head. Despite promising in vitro biomechanical properties, capitellar wear is still a common finding with pyrocarbon RHAs. Despite these factors, pyrocarbon radial head implants are a viable option for radial head arthroplasty., Level of Evidence: II; Systematic review., (Copyright © 2023. Published by Elsevier Masson SAS.)