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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]

The MoPyc radial head arthroplasty (RHA) is a monopolar implant with a pyrocarbon head that obtains rigid fixation via controlled expansion of the titanium stem. The aim of this study was to evaluate the short-term to midterm outcomes of MoPyc RHA. Between 2002 and 2021, 139 MoPyc RHA were implanted in 139 patients with a RH fracture. The mean follow-up was 5.9 years ± 3.5 (range 1-16). Range of motion, mean Mayo Elbow Performance Score (MEPS), Quick Disabilities of the Arm, Shoulder and Hand score, visual analog scale (VAS), radiographic outcome, and reason for failure were recorded. The mean MEP, Quick Disabilities of the Arm, Shoulder and Hand, and VAS scores were 89.1 ± 2.2 (range, 45-100), 17.5 ± 16.7 (range, 0-78), and 0.8 ± 1.6 (range, 0-50), respectively. Stress shielding (SS) and osteolysis around the stem were identified in 92 (66%) and 20 (14%) patients. A total of 47 (29%) patients experienced at least 1 complication and 29 (21%) of them required re-intervention. Persistent stiffness (n = 12; 9%) was the most common complication. No painful loosening was noted. Osteolysis around the stem, presence of an autoexpanding stem, and overstuffing were associated with a lower MEPS and an increase in VAS (P <.05). SS was associated with an increase in MEPS (adjusted beta coefficients= 6.92; P <.001) and lower VAS (adjusted beta coefficients= −0.69; P =.016). The autoexpending stem increased the likelihood of SS after RHA (adjusted odds ratio = 1.49; P =.001). A well-fixed MoPyc RHA provided satisfactory short to midterm outcomes, without painful loosening. However, the autoexpanding stem system was associated with poorer functional outcomes and increased the likelihood of SS. [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 paper deals with the processing of rubber‑containing products by pyrolysis in order to obtain pyrolytic carbon, which is of practical interest for the needs of the foundry. It has been established that the process of gas phase evolution during rubber pyrolysis proceeds in the temperature range of 50–550 °C, the maximum release peaks for all detected substances are in the range of 375–500 °C, the total release is over 140 mg per kg of feedstock. It was found that the concentration and temperature of the exhaust gases make it possible to neutralize them in an autocatalytic mode using the principle of filtration combustion. It is shown that the optimal temperature for obtaining a solid carbonaceous residue (target product) is 320–380 °C, an increase in temperature above 500 °C leads to a decrease in the mass fraction of pyrolytic carbon from 64.8 to 31.9 %, respectively, the proportion of exhaust gases increases from 5 to 8 %, and heating oil yield from 30.2 to 60.1 %.

The new scheme of the rapid preconcentration of volatile organic substances followed by the thermodesorption and gas chromatographic determination by using a flame ionization detector is proposed for the analysis of air. The scheme implies a change in the geometry of the adsorbent layer in a column during the transition from adsorption to thermal desorption steps. The extraction of analytes is carried out in a wide tube, allowing quantitative adsorption at higher flow rates of the analyzed air passed through the magnetic sorbent held in a thin layer retained by a permanent magnet without any supporting frits. Novel magnetic adsorbents composed of magnetite or a zirconia/magnetite core and pyrocarbon shell are developed for this application. At the end of the adsorption step, the magnet moved out of the system, and the adsorbent transferred under the gravity force into a narrow tube, which provides the more efficient heating of the adsorbent and minimal blurring of the analyte zones during the subsequent thermal desorption. The proposed scheme allows a significant reduction (approximately 10 times) of the time required for the preconcentration of analytes, which is illustrated by the GC determination of alcohols (butanol-1, pentanol-1), phenol, and o-cresol in the air. [ABSTRACT FROM AUTHOR]

Urea–formaldehyde (UF) resin is difficult to degrade and classified as hazardous organic waste. To address this concern, the co-pyrolysis behavior of UF resin with pine sawdust (PS) was studied, and the adsorption properties of pyrocarbon were evaluated with Cr (VI). Thermogravimetric analysis revealed that adding a small amount of PS can improve the pyrolysis behavior of UF resin. Based on the Flynn Wall Ozawa (FWO) method, the kinetics and activation energy values were estimated. It was observed that when the amount of UF resin exceeded twice that of PS, the activation energy of the reaction decreased, and they acted synergistically. The characterization of pyrocarbon samples showed that the specific surface area increased with the increase of temperature, while the content of functional groups showed the opposite trend. Intermittent adsorption experiments showed that 5UF + PS400 achieved 95% removal of 50 mg/L Cr (VI) at 0.6 g/L dosage and at pH 2. The adsorption process was consistent with the Langmuir isotherm and pseudo-second-order kinetics, and the maximum adsorption was 143.66 mg/g at 30 ℃. Furthermore, the adsorption process consisted of electrostatic adsorption, chelation, and redox reaction. Overall, this study provides a useful reference for the co-pyrolysis of UF resin and the adsorption capacity of pyrocarbon. [ABSTRACT FROM AUTHOR]

Hemiarthroplasty is often considered in the setting of preserved glenoid cartilage given the high risk of revision associated with total shoulder arthroplasty. Pyrocarbon (PyC) has been used as an implant material that theoretically allows for formation of a neo-membrane that would act like cartilage to reduce glenoid wear. The purpose of this study was to evaluate the clinical outcomes, radiographic outcomes, revision rates, and complication rates in the existing literature on shoulder hemiarthroplasty using PyC. The MEDLINE, Embase, and Scopus databases were searched for articles relating to shoulder hemiarthroplasty using the terms "pyrocarbon" or "pyrolytic carbon." Abstracts and articles were screened against predefined inclusion and exclusion criteria, with a minimum of 24 months' follow-up required. Data on patient demographic characteristics, clinical outcome scores, complications, revision rates, and radiographic findings were recorded. Where appropriate, meta-analysis was performed. Twelve studies were selected for final inclusion, with a total of 536 patients. Among the studies reporting preoperative and postoperative range of motion (ROM), an overall improvement in ROM was observed. The mean Constant score was 70.9 points postoperatively, with a mean improvement of 36.2 points (n = 359, 9 studies). Radiographically, 22.8% of patients (n = 536, 8 studies) had evidence of glenoid erosion, 10.4% had changes in implant positioning, and 9.9% had tuberosity thinning. In addition, 1.5% of patients had radiographic subacromial space reduction, whereas 0.7% had an increase in tuberosity thickness. Across all studies, there was an 8.6% complication rate, with the most common cause being glenoid erosion (2.6%, n = 14). There was an overall 7.7% revision rate (n = 41), with 63% of revisions (n = 26) undergoing conversion to reverse or total shoulder arthroplasty. PyC hemiarthroplasty shows overall improvements in ROM and patient-reported outcomes for patients. However, there remains concern for glenoid erosion on radiographic evaluation at minimum 2-year follow-up. Although preliminary studies have shown encouraging results, this systematic review emphasizes the need for longer-term follow-up studies with further radiographic evaluation of the severity of glenoid erosion and the association with functional outcomes and failure risk. [ABSTRACT FROM AUTHOR]

The functional results of proximal row carpectomy with a proximal capitate resurfacing using a pyrocarbon implant were evaluated in a retrospective, multicentric, multi-operator study. The outcomes of patients operated on at five surgical centres between January 2005 and December 2018 were reviewed. The data were collected by an independent observer during standardized consultations. Based on 30 patients with a mean follow-up of 7 years, the median range of flexion and extension was 65° and the median radioulnar tilt was 45°. The median Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) score was 14 and the improvements in strength and pain were good. Compared with the preoperative values, significant improvements were seen in the flexion and extension range of motion, radioulnar tilt and pain score. No postoperative complications were recorded. Level of evidence: IV [ABSTRACT FROM AUTHOR]

Background: In vitro data demonstrate the potential benefits of the pyrocarbon as a bearing material against cartilage or bone. And pyrocarbon-free interposition arthroplasty has been used with positive outcomes for over 10 years for hand and wrist joint replacements. This study reports the midterm results of a Pyrocarbon Interposition Shoulder Arthroplasty (PISA) in primary and secondary glenohumeral osteoarthritis and in avascular osteonecrosis. Methods: This prospective noncontrolled, multicenter study included 67 consecutive patients who underwent PISA in France and Sweden. Results: A cohort of 48 patients, aged 50 ± 12 years, was available for clinical assessment at a mean follow-up of 67.6 ± 9.3 months. A favorable change was reported with a mean absolute Constant score improvement of 32 ± 20 points. The highest Constant score improvement was observed in patients with avascular osteonecrosis (42 ± 18 points; P ≤ .0001). Between the earliest and the latest follow-up, radiographic analyses revealed only 2 major glenoid erosions and 4 tuberosity thinnings and thus that 86.4% of 44 shoulders remained stable with no or minor radiologic evolutions. The survival rate was 84 % at 65 months of follow-up considering all causes of revision. Conclusion: The radiographic findings seem to confirm the interest of pyrocarbon in preserving bony surfaces. But the risk of tuberosity thinning suggests considering the use of PISA with caution in most degenerative glenohumeral joint pathologies, although the midterm outcomes highlight PISA as a suitable solution for patients presenting with posttraumatic osteonecrosis without malunion of the tuberosities and with an intact rotator cuff.

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]

The structure and mechanical properties of C/C composites prepared by isothermal isobaric chemical vapor infiltration (ICVI) were investigated to evaluate the influence of introducing graphene. The results indicated that adding graphene significantly improved the texture of pyrocarbon. The pure pyrocarbon was primarily composed of smooth laminar (SL) structure, while the pyrocarbon in composites containing graphene was dominated by regenerative laminar (ReL) structure. Furthermore, with 0.66 wt% addition of graphene, the compression performance of the C/C composites was prominently improved by 70.9%, increasing from 107.37 MPa to 183.45 MPa, while the bending strength of the C/C composites was slightly decreased. The variation of mechanical properties was attributed to graphene-induced weakening of interfacial bonding and improved texture of pyrocarbon, resulting in a more compact arrangement of carbon layers and better integrity of the matrix. This work contributed to the understanding of the improved properties and structure of C/C composites with graphene addition. [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.)

The process of inorganic and organic components temperature transformation of metal waste into solid and gaseous products in a continuous hot briquetting muffle furnace has been studied. The composition of the hydrocarbon atmosphere formed in the muffle under conditions of limited access to the oxidizer has been determined. It is shown that the thermal destruction of the coolant oil phase proceeds according to a complex mechanism of consecutive reactions, including polycondensation, polymerization, and deep compaction with a constant decrease in the hydrogen content and ends with the formation of a coke‑like carbon residue on the surface of metal particles and an air suspension of finely dispersed carbon particles (smoke). When it is heated to hot briquetting temperatures of 750–850 °C, chemically active dispersions of ferrous metals are protected from oxidation first by a hydrocarbon gas with a density of 9.0–13.5 kg/m3, then by a pyrocarbon coating with a thickness of 0.1–0.3 mm up to the completion of the processes of pressing and cooling the briquette.

The new scheme of the rapid preconcentration of volatile organic substances followed by the thermodesorption and gas chromatographic determination by using a flame ionization detector is proposed for the analysis of air. The scheme implies a change in the geometry of the adsorbent layer in a column during the transition from adsorption to thermal desorption steps. The extraction of analytes is carried out in a wide tube, allowing quantitative adsorption at higher flow rates of the analyzed air passed through the magnetic sorbent held in a thin layer retained by a permanent magnet without any supporting frits. Novel magnetic adsorbents composed of magnetite or a zirconia/magnetite core and pyrocarbon shell are developed for this application. At the end of the adsorption step, the magnet moved out of the system, and the adsorbent transferred under the gravity force into a narrow tube, which provides the more efficient heating of the adsorbent and minimal blurring of the analyte zones during the subsequent thermal desorption. The proposed scheme allows a significant reduction (approximately 10 times) of the time required for the preconcentration of analytes, which is illustrated by the GC determination of alcohols (butanol-1, pentanol-1), phenol, and o-cresol in the air.

Background: Pyrocardan® (Wright Medical-Tornier) is a pyrocarbon implant proposed in the treatment of trapeziometacarpal joint (TMCJ) osteoarthritis. Our aim was to assess the clinical and radiographic results after Pyrocardan® arthroplasty at midterm follow-up.Methods: In this prospective monocentric study, we enrolled 119 patients treated with Pyrocardan® for TMCJ osteoarthritis and followed up at a minimum of four years. The clinical outcome was assessed through the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, the Visual Analog Score (VAS) for pain and the Kapandji score collected pre-operatively, at three, six and 12 months, then yearly. Hand radiographs were taken before surgery, at three months and every year. Complications and re-operations were also recorded.Results: The mean follow-up was 5.2 years (range, 4-9). DASH, VAS and Kapandji scores significantly improved at three (p < 0.001 in all cases) and six months (p < 0.001, p = 0.01 and p < 0.001, respectively), remaining stable over time. The dislocation and subluxation rates were 3.3% (4 cases) and 16.8% (20 patients), respectively. The two year, four year and seven year survivorship of the implant was 99%, 98% and 95%, respectively.Conclusion: Pyrocardan® arthroplasty provides a satisfactory clinical and radiographic outcome for treating TMCJ osteoarthritis, with a 97% survival rate at four years. We advocate comparative studies with more common techniques (i.e., trapeziectomy) to verify its cost-effectiveness. [ABSTRACT FROM AUTHOR]

Background: Restoring the radial head as a stabiliser of the elbow is considered important in cases where there is an associated bony or ligamentous injury. A variety of radial head prostheses are available. There are no reports of the survivorship of a short-stem press-fit radial head prostheses with pyrocarbon bearing. Patients and methods: With institutional review board approval, a retrospective case-note analysis was performed of a consecutive single-surgeon case series of the Integra LifeScience pyrocarbon radial head prostheses (Carbon Modular Radial Head) from October 2010 to October 2019 in a tertiary referral centre. The series was divided into acute trauma and salvage cohorts. Kaplan–Meier survivorship analysis was conducted. Results: 36 patients were included, 23 (64%) for acute injuries and 13 (36%) for failed initial treatment. Of the acute injuries, 20 (87%) had a Wrightington type-C elbow fracture-dislocation. Reoperation was performed in 4 (11%) patients; 10 (28%) had possible loosening on radiographs. The implant survival rate was 94% at shortest follow-up of 17 months (mean 70 months). Discussion: Treatment of complex radial head fractures using a pyrocarbon-bearing, anatomic press-fit design provides satisfactory short-term survivorship in this case series. The implant should be used with caution in salvage cases, due to higher rates of loosening seen in this cohort. [ABSTRACT FROM AUTHOR]

Modification of tubular ceramic membranes made of clay minerals, which were obtained by slip casting (produced by the Dumansky Institute of Colloid Chemistry and Water Chemistry of the National Academy of Sciences of Ukraine) was carried out. The membranes were modified with pyrocarbon, which was obtained by carbonization of a precursor - poly(urethane urea)s. The carbonization precursor was synthesized from polyisocyanate (average functionality 2.7) and laprol grade 5003, which was introduced into the membrane by impregnation of the corresponding solutions in ethylacetate. When laprol reacts with polyisocyanate, three-dimensional polyurethane is formed. Since undried reagents were used, water entered the pores of the membrane, which reacted with the NCO groups of the polyisocyanate to form polyurea. The parallel course of these reactions leads to the formation of poly(urethane urea)s in the pores of the membrane. Carbonization was carried at 800 °C in an argon flow. The apparent density and open porosity of the membranes were determined by CCl4 uptake. After modification, the open porosity of the membrane decreased from 29.9 to 27.3 %, the apparent density increased from 1.86 to 1.87 g/cm³. The composition and structure of the membranes were studied by X-ray diffraction analysis and SEM. It is shown that the obtained modifier is pyrocarbon - the relative intensity of reflexes increases at 26,0 - 26,4 and 41,3 and 44,2° 2Θ. Pyrocarbon covers the surface of the pores with a continuous layer, and there are also three-dimensional formations of various shapes and sizes from several nm to several microns. Testing of modified membranes was carried out by water purification from direct scarlet dye and from Ca2+ of calcium chloride using the baromembrane method at a working pressure of 0.7 MPa. The unmodified membrane does not retain direct scarlet dye and Ca2+ at all. Tests of modified membranes have shown that the membranes acquire ultrafiltration properties. The retention factor (R) for direct scarlet dye is 100 % and 25 % for Ca2+. [ABSTRACT FROM AUTHOR]

Pyrocarbon implant hemiarthroplasty is a treatment option for select patients with trapeziometacarpal joint arthritis. The long-term revision rates after implant arthroplasty can be as high as 30%. Revision to trapeziectomy has been described for patients who require implant removal; however, few studies have assessed outcomes in patients in this subgroup. This was a retrospective review of patients who underwent the conversion of a pyrocarbon carpometacarpal implant to trapeziectomy and suspensionplasty from 2003 to 2019. Patients who met the criteria were then compared with a matched cohort who underwent primary trapeziectomy and suspensionplasty. Patients were matched based on the revision procedure, age, and duration of follow-up. Data regarding demographic information, range of motion, grip and pinch strengths, and the need for subsequent procedures were collected. Twenty-five patients underwent the removal of their pyrocarbon carpometacarpal implant. The patients underwent revision to Thompson suspensionplasty (n = 14), the Weilby procedure (n = 5), ligament reconstruction tendon interposition (n = 2), or a suture-based suspension procedure (n = 4). The age, sex, and preoperative range of motion and strength measures were similar between the 2 groups. All the patients complained of moderate-to-severe pain prior to surgery, which improved in both groups after surgery. Patients who underwent the removal of a pyrocarbon arthroplasty implant lost 6.4° of palmar abduction after surgery. The postoperative grip, opposition strength, apposition pinch strength, and radial and palmar abduction were similar between the 2 groups. The removal of a pyrocarbon carpometacarpal implant using subsequent trapeziectomy successfully relieves pain in patients in whom pyrocarbon arthroplasty has failed. After revision, patients may lose abduction motion but have similar strength compared with those who undergo primary trapeziectomy. Therapeutic III. [ABSTRACT FROM AUTHOR]

In the framework of SiC/SiC composite development for nuclear applications, the influence of pyrocarbon interphase texture and thickness on the mechanical behavior both on as-processed materials and on irradiated materials is a major concern. Thus, the PyC interphase influence has to be clearly addressed to define its optimal chemical vapor infiltration processing parameters. For this purpose, specific 2.5D SiC/SiC composites reinforced with Hi-Nicalon S fibers and with two kinds of PyC texture and thickness were produced. Transmission electronic microscopy allowed PyC thickness and microstructure/texture characterizations, whereas push-out and tensile tests were employed as experimental mechanical procedures. The original result is that PyC nature directly influences the interfacial shear stress and failure mode of the weakest interface, regardless of the PyC thickness within the studied range. Adhesive failure or cohesive failure are highlighted depending on the PyC CVI deposition mechanisms. Similar post-irradiation characterizations will be required to assess the role of irradiation on the PyC microstructure/texture evolution and mechanical behavior of these materials. [ABSTRACT FROM AUTHOR]

Background: Unconstrained pyrocarbon and metal-on-polyethylene (MoP) proximal interphalangeal (PIP) joint arthroplasty is an increasingly popular alternative to silicone implants and arthrodesis. This systematic review appraises their outcomes. Methods: Thirty studies comprising 1,324 joints (813 pyrocarbon, 511 MoP) were included. Mean patient age was 59 years (38–78) and mean follow-up period was 54 months (12–118). Results: There were mean improvements of 4.5 points (2–6.9) in pain visual analogue score, 10.5° (−26 to 58) in range of motion (ROM), 3.1 kg (−4 to 7) in grip strength, 0.6 kg (−1.5 to 2) in pinch strength and 18 points (−3 to 29) in the disabilities of the arm, shoulder and hand score, with no significant differences between implant types. ROM gains deteriorated over time. Clinical complications were frequent (23%) and significantly more common with pyrocarbon, as were radiographic complications. However, most were mild-moderate and did not necessarily correlate with negative outcomes or dissatisfaction. Overall re-operation rate was 21%, and revision rate 11%, both more frequent with pyrocarbon. Most revisions were within 24 months, beyond which survival was maintained up to 10 years. Conclusions: Unconstrained PIP joint arthroplasty is effective in improving pain scores, active ROM, grip/pinch strength and patient-reported outcome measures, particularly in patients with osteoarthritis. Results are generally maintained at least to the medium term, although gains diminish in the longer term. Complication and early revision rates are high, particularly with pyrocarbon implants. Most patients express positive attitudes to arthroplasty, with significant improvements in patient-reported outcome measures for both pyrocarbon and MoP implants. Patients with post-traumatic and inflammatory arthropathy are generally less satisfied. There is currently insufficient data to recommend one implant type over another, although the early-to-medium term results of MoP implants are promising. Prospective surveillance via small joint registries is recommended. Level of Evidence: Level III (Therapeutic) [ABSTRACT FROM AUTHOR]

The optimal surgical management of glenohumeral osteoarthritis in young patients remains an unsolved problem. Humeral resurfacing hemiarthroplasty and stemmed hemiarthroplasty using metallic heads are 2 surgical options that avoid the complications of loosening or wear of the glenoid component seen in total shoulder arthroplasty. Despite the potential benefits, improvement in survivorship has not been demonstrated from joint registry studies or other studies at mid-term follow-up. This is predominantly because of glenoid erosion and pain that occur when the metal resurfaced head articulates with the native glenoid. The use of pyrolytic carbon (pyrocarbon) as a resurfacing material has been proposed as an alternative bearing surface thought to reduce glenoid erosion owing to a marked reduction in wear rates in vitro. This study aimed to compare the survivorship of shoulder hemi-resurfacing using pyrocarbon with shoulder hemi-resurfacing and stemmed hemiarthroplasty using metallic heads. Data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) were analyzed for all patients aged <55 years who had undergone a primary shoulder replacement for osteoarthritis from April 16, 2004, to December 31, 2019. The outcomes of shoulder procedures using pyrocarbon hemi-resurfacing were compared with procedures using metal hemi-resurfacing and metal stemmed hemiarthroplasty. The reasons for revision in each arthroplasty class were analyzed. The analyses were undertaken using Kaplan-Meier estimates of survivorship and hazard ratios (HRs) from Cox proportional hazards models. We analyzed 393 primary shoulder procedures, of which 163 were pyrocarbon hemi-resurfacing procedures, 163 were metal hemi-resurfacing procedures, and 67 were metal stemmed hemiarthroplasties.The cumulative percentage of revision at 6 years was 8.9% for pyrocarbon hemi-resurfacing, 17.1% for metal hemi-resurfacing, and 17.5% for metal stemmed hemiarthroplasty. Pyrocarbon hemi-resurfacing prostheses had a statistically lower revision rate than other hemi-resurfacing prostheses (HR, 0.41; 95% confidence interval, 0.18-0.93; P =.032). Pain, prosthesis fracture, and infection were the key reasons for revision. No pyrocarbon hemi-resurfacing cases were revised for glenoid erosion. In male patients, pyrocarbon humeral resurfacing had a lower cumulative percentage of revision compared with metal stemmed hemiarthroplasty (HR, 0.32; 95% confidence interval, 0.11-0.93; P =.037). Pyrocarbon humeral resurfacing arthroplasty had statistically lower revision rates at mid-term follow-up in patients aged <55 years compared with other hemi-resurfacing procedures. [ABSTRACT FROM AUTHOR]

The number of patients presenting to the hand surgeon with severe rheumatoid disease has decreased with the introduction of more effective medical management. However some rheumatoid patients will undergo disease progression despite this. MCPJ and PIPJ replacement can be effective surgical treatments in these patients but patient selection is crucial. Patients undergo surgery hoping to achieve improvements in pain, hand function and appearance. Multiple types of implant have been introduced over the years; however, silicone remains the most reliable option in terms of survivorship, complications and achieving the aims of rheumatoid patients., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

• Development of comprehensive 3D CFD model for commercial hot wall reactor. • Understanding of the critical parameters affecting the film performance. • Correlation of growth patterns and operating conditions using support vector machine. • Optimal design using machine learning combined with Nelder-Mead algorithms. Chemical vapour deposition (CVD) of pyrocarbon (PyC) effectively fabricates advanced carbon materials. Controlling the nanotexture of PyC is critical for the desired application. Reactor operating conditions, including temperature, pressure, inlet flow rate, reactant concentration, govern thickness, and film uniformity. The optimal film performance can be obtained by selecting appropriate process conditions. However, the optimisation of the CVD reactor is challenging due to the highly nonlinear and multi-variable nature of the process. In this study, the support vector machine, a robust supervised learning algorithm and Nelder-Mead algorithm are coupled to optimise the CH 4 pyrolysis in a commercial CVD reactor. To this end, a comprehensive CFD model for CH 4 pyrolysis in a commercial CVD reactor is first constructed. The model accuracy is improved by considering temperature-dependent transport properties of gas mixture and incorporating the detailed gas and surface chemistry (14 species and 32 reactions). The deposition rate and film uniformity are then obtained using a parametric study. Subsequently, the support vector machine (SVM) is employed to deduce the correlation between the PyC growth rate/film uniformity and operating variables. It has been found that the accuracy of SVM is better than the linear regression model. Finally, SVM coupled with the Nelder-Mead algorithm is proposed to optimise the CVD process parameters to maximise the PyC film quality. [ABSTRACT FROM AUTHOR]

Scapholunate advanced collapse collapse (SLAC) is a challenging topic for hand surgeons. The adaptative proximal scaphoid implant (APSI) (Bioprofile-Tornier) is a pyrocarbon ovoid shaped interpositional implant, that allows adaptive mobility during motion. The aim of this systematic review is to analyze the clinical and radiological outcomes of APSI implants and possible complications. We performed a literature search combining the following key-words: "APSI", "Scaphoid's proximal pole", "implant", "scaphoid avascular necrosis", "SLAC", "SNAC", "pyrocarbon", "prosthesis", and "spacer" with no limitations for year of publication. We selected seven studies considered relevant to our systematic review. All studies described an improvement in the grip strength and the flexion extension arch compared to pre-operative values. The percentage of patients who reported progression of osteoarthritis (OA) with APSI was 17.3%, and implant's mobilization has a rate 5.1% (8/156). In conclusion the APSI implant is a reliable alternative for the treatment of SNAC wrist and SLAC wrist. [ABSTRACT FROM AUTHOR]

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.)

An analytical model is developed to obtain qualitatively and semiquantitatively estimate the changes in the integral pore size during the oxidation of heterophase materials. The model is tested on studying the oxidation of CCCM with a pyrocarbon matrix at 600°C up to a mass loss of 75 wt %. The change in the pore size is analyzed to quantify the structural degradation of the composite. [ABSTRACT FROM AUTHOR]

Background: Proximal Row Carpectomy (PRC) is a widespread, safe and effective salvage surgical procedure for wrist arthritis. Some authors believe that PRC results in low grip strength (GS), due to the loss of carpal height, supporting the idea to discourage PRC in high-demanding patients. Resurfacing Capitate Prosthesis Implant (RCPI) allows extending the indication for PRC also in case of deformity and/or arthritis of the head of capitate, with possible implications of clinical outcomes, including GS. Methods: Retrospective multicentre study on a population of active workers, affected by secondary post traumatic wrist arthritis, who underwent PRC (27 patients) or PRC + RCPI (20 patients), Primary outcome was to assess GS between PRC and PRC + RCPI. Secondary outcome was to assess CHR and to search for any possible contributors to GS. Active range of motion (AROM), hand function (DASH, Work-DASH, VAS, PRWHE), pain, time to return to work, job maintenance, major complications and general satisfaction were also assessed. Results: PRC + RCPI results in more GS maintenance compared with PRC alone, with higher values of CHR. CHR values were associated with GS with a good correlation. According to linear regression model analysis within PRC + RCPI group (GS–CHR), it is esteemed that the increase in parameter CHR is associated with an increase in parameter GS. Looking at a multiple linear regression model analysis built on the whole sample (GS% increase – (group × CHR) + GS% pre-operative). It is estimated that the increase of one unit of the GS coefficient is associated with an increase in GS% increase. Furthermore, higher pre-operative GS values positively influence post-operative GS. No differences were revealed between the two treatments in terms of the remaining secondary outcomes. Conclusions: PRC alone and PRC + RCPI are both effective salvage procedures for wrist arthritis. RCPI provides a better GS preservation, in part due to the carpal height preservation. [ABSTRACT FROM AUTHOR]

Background: Unconstrained pyrocarbon and metal-on-polyethylene (MoP) proximal interphalangeal (PIP) joint arthroplasty is an increasingly popular alternative to silicone implants and arthrodesis. This systematic review appraises their outcomes. Methods: 30 studies comprising 1,324 joints (813 pyrocarbon, 511 MoP) were included. Mean patient age was 59 years (38 to 78) and mean follow-up period was 54 months (1.2 to 380). Results: There were mean improvements of 4.5 points (2 to 6.9) in pain Visual Analogue Score, 10.5° (−26 to 58) in range of motion (ROM), 3.1 kg (−4 to 7) in grip strength, 0.6 kg (−1.5 to 2) in pinch strength, and 18 points (−3 to 29) in the Disabilities of the Arm, Shoulder and Hand score, with no significant differences between implant types. ROM gains, in particular, deteriorated over time. Clinical complications were frequent (23%), and significantly more common with pyrocarbon, as were radiographic complications. However, most were mild-moderate and did not necessarily correlate with negative outcomes or dissatisfaction. Overall reoperation rate was 21%, and revision rate 11%, both more frequent with pyrocarbon. Most revisions were within 24 months, beyond which survival was maintained up to ten years. Conclusions: Unconstrained PIP joint arthroplasty is effective at improving pain scores, active ROM, grip/pinch strength, and patient reported outcome measures, particularly in patients with osteoarthritis. Results are generally maintained at least to the medium term, although gains diminish in the longer term. Complication and early revision rates are high, particularly with pyrocarbon implants. The majority of patients express positive attitudes to arthroplasty, with significant improvements in patient-reported outcome measures for both pyrocarbon and MoP implants. Patients with post-traumatic and inflammatory arthropathy are generally less satisfied. There is currently insufficient data to recommend one implant type over another, although the early-to-medium term results of MoP implants are promising. Prospective surveillance via small joint registries is recommended. [ABSTRACT FROM AUTHOR]

The outcomes with metal head hemiarthroplasties (HA) are contrasted, especially in young, active patients. An innovative Pyrocarbon interface was introduced in 2014 in order to decrease potential glenoid wear. The aim of this study is to evaluate survival and short-term results of HA with a pyrocarbon head. We conducted a retrospective single-centre study: 30 consecutive patients underwent HA with pyrocarbon humeral head and were assessed with a minimum follow-up of 2 years. The mean age at surgery was 54 ± 13 years; 38% of patients (n = 13) had undergone surgery at least once on the affected shoulder. Depending on the aetiology, 4 groups were analyzed: group 1 (osteonecrosis, n = 12), group 2 (primary gleno humeral osteoarthritis, n = 10), group 3 (fracture sequelae, n = 4) and group 4 (revision, n = 4). A significant improvement in clinical results was documented at mean follow-up of 38 months: mean Constant score (preop 35 ± 15 vs. postop 67 ± 19 points; <0.0001) and mean SSV (Subjective Shoulder Value; preop 35 ± 20 vs. postop 79 ± 16; <0.0001). Four patients (13%) required revision surgery with an average follow-up of 35 ± 12 months: two patients for infection (one in group 1 and the other in group 3), one patient for humeral false path (group 3) and one patient for rotator cuff tear (group 1). No revision was performed in groups 2 and 4. Glenoid wear did not increase significantly, regardless of the indication. In the subgroup analysis, the best gain was found in group 2: Constant score (+33 points; P <.001) and SSV (+50%; P <.001). The best results were obtained in group 4: Constant score 75 points and SSV score 87%. HemiPYC provided satisfactory clinical outcomes without glenoid wear at short-term follow-up. Disappointing results were recorded in the case of severe fracture sequelae. Mid and long-term studies should be carried out to confirm these results. Level IV, retrospective case series. [ABSTRACT FROM AUTHOR]

Introduction: The goal of this study was to provide an insight into the clinical results after modular short-stem shoulder arthroplasty for various indications. Materials and methods: A consecutive cohort study of 76 patients followed up for 23–55 (mean 31.4) months. 23 anatomical (TSA), 32 reverse (RSA) and 21 hemi-prostheses with a pyrocarbon head (PyC), using a modular short stem with proximal porous coating were implanted. Range of motion, pain and Constant score (CS) were recorded. Comparisons of pre- vs postoperative outcomes, between prosthesis types and indications, were made. Results: All prosthesis types brought about a significant improvement (p < 0.05) in all measured outcomes. TSA had a significantly higher increase in the CS than PyC and RSA (p = 0.002 and 0.003, respectively). TSA produced superior gains in all ROM compared with RSA (p < 0.02). RSA brought about significantly smaller improvements in internal rotation than TSA and PyC (p = 0.0001 and 0.008, respectively). TSA had greater pain relief than PyC (p = 0.02). TSA with Walch A glenoids seemed to improve more than type B in the CS. PyC patients with Walch B glenoids improved more than Walch A (p = 0.03). When implanted due to Osteoarthritis (OA), PyC had a comparable final outcome to TSA (p = 0.95), although the preoperatively worse TSA patients had a greater improvement in the CS (p = 0.026). The outcome of RSA did not differ between indications, but Walch A glenoids tended to improve more. Conclusions: Using a second-generation short-stem shoulder prostheses, TSA achieves the best clinical improvements overall, especially for OA with a Walch A glenoid. Despite refixation of the subscapularis tendon in all cases, RSA has inferior internal rotation than TSA and PyC, suggesting a mechanical limitation. OA, a Walch B glenoid and arthritis caused by instability seem to be ideal indications when considering PyC. [ABSTRACT FROM AUTHOR]

This study aimed to describe the clinical outcomes and complications of 10 cases of pyrocarbon interposition shoulder arthroplasty (PISA). The clinical and radiographic records of 10 patients who underwent PISA using the InSpyre shoulder prosthesis (Tornier-Wright) between July 2012 and March 2017 were reviewed. The mean age at surgery was 55 years. Surgical indications included patients aged <60 years with Walch type B glenoid glenohumeral osteoarthritis (n = 7), avascular necrosis (AVN) of the humeral head (n = 1), or secondary severe glenohumeral osteoarthritis with axillary nerve dysfunction (n = 2). Outcomes of interest were postoperative complications and need for revision surgery, preoperative and postoperative patient-reported outcomes (Constant score [CS] and Subjective Shoulder Value [SSV]), and range of motion. The radiographic characteristics of the implants were evaluated. Among the 10 patients, 5 underwent revision to reverse shoulder arthroplasty during the study period owing to poor clinical outcomes based on the CS and SSV. All 5 revised patients had Walch type B glenoid morphology at the time of the index procedure. The mean time to revision surgery in this subset of patients was 60 months. The remaining 5 patients who did not undergo any revision procedure had significant improvement in mean CS and SSV from 30-65 points and 32%-87%, respectively, but at a shorter duration of follow-up of 35 months. High clinical failure rate and poor results at mean 5-year follow-up were found in younger PISA patients with baseline Walch B glenohumeral osteoarthritis. We would caution against use of PISA in this challenging patient population. PISA yielded more favorable short-term outcomes in patients with humeral-sided deformity or severe secondary glenohumeral osteoarthritis with axillary nerve dysfunction; however, longevity of the implant in this population remains unclear. [ABSTRACT FROM AUTHOR]

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]

In the context of shoulder surgical replacement, a new generation of spherical interposition implants has been developed, with the implant being a mobile spacer rubbing against the glenoid cartilage and humeral bone cavity. The aim of the present study was to compare pyrocarbon (PyC) versus cobalt-chromium (CoCr) implants, regarding preservation and regeneration of the surrounding tissues. The effect of the biomaterials on chondrocytes was analysed in vitro. Murine primary chondrocytes were grown on discs made of PyC or CoCr using two culture media to mimic either cartilage-like or bone-like conditions (CLC or BLC). Chondrocytes did grow on PyC and CoCr without alteration in cell viability or manifestation of cytotoxicity. The tissue-like cell membranes grown under BLC were examined for the chondrocyte’s ability to mineralise (by alizarin red matrix staining, calcium deposit and alkaline phosphatase activity) and for their mechanical properties (by rheological tests). For the chondrocytes grown under CLC and BLC, extracellular matrix components were analysed by histological staining and immunolabelling. Under CLC, PyC promoted type II collagen expression in chondrocytes, suggesting that they may generate a more cartilage-like matrix than samples grown on both CoCr and plastic control. In BLC, the tissue-like cell membranes grown on PyC were more mineralised and homogenous. The mechanical results corroborated the biological data, since the elastic modulus of the tissue-like cell membranes developed on the PyC surface was higher, indicating more stiffness. Overall, the results suggested that PyC might be a suitable biomaterial for spherical interposition implants.

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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.)