Introduction. Despite the positive outcomes in shoulder joint replacements in the last two decades, polyethylene wear debris in metal-on-polyethylene artificial shoulder joints is well-known as a limitation in the long-term survival of shoulder arthroplasties systems. Consequently, there is an interest in the use of novel materials as an alternative to hard bearing surfaces such as pyrolytic carbon layer (PyroCarbon). Materials and Methods. In the present study, the unique Newcastle Shoulder Wear Simulator was used (Smith et al., 2015; Smith et al., 2016) to evaluate the wear behavior of four commercially available PyroCarbon humeral heads 43 mm diameter, articulating against conventional ultra-high molecular weight polyethylene (UHMWPE) glenoid inserts with a radius of curvature of 17.5 mm to form an anatomic total shoulder arthroplasty. A physiological combined cycled “Repeat-motion-load” (RML) (Ramirez-Martinez et al., 2019) obtained from the typical activities of daily life of patients with shoulder implants was applied as a simulator input. A fifth sample of the same size and design was used as a soak control and subjected to dynamic loading without motion during the wear test. The mean volumetric wear rate of PyroCarbon-on-polyethylene was evaluated over 5 million cycles gravimetrically and calculated on the basis of linear regression, as well as the change in surface roughness (S. a. ) of the components using a non-contacting white light profilometer throughout the test. Results. The gravimetric analysis showed a mean volumetric wear rate and standard deviation of 19.3±9.5 mm. 3. /million cycles for the UHMWPE glenoid inserts, whereas PyroCarbon humeral head counterparts did not exhibit a loss in mass throughout the test. The roughness values of the UHMWPE glenoid inserts decreased (P < .001), changing from 296±28 nm to 32±8 nm at the end of the test. In contrast, the PyroCarbon humeral heads did not show a significant change (P = .855) over the 5 million cycles; remained in the same range (21±2 nm to 20±10 nm) with no evidence of wear damage on the surface. Conclusions. This is the first in-vitro shoulder simulator study of a PyroCarbon on UHMWPE articulation. Wear rates were similar to that found to well-proven metal on UHMWPE shoulder arthroplasties. While it was interesting to see that the PyroCarbon did not roughen over the test duration, the lack of an appreciable reduction in wear of the UHMWPE component when articulated with an expensive and complex to manufacture PyroCarbon component likely means there is little clinical cost-benefit in the use of a PyroCarbon on UHMWPE shoulder implant. Declaration of competing interest. Prof. Ian A. Trail received some royalties and research support from Wright Medical Group N.V. None of the other authors, their immediate families, and any research foundation with which they are affiliated did not receive any financial payments or other benefits from any commercial entity related to the subject of this article. For any figures or tables, please contact authors directly

Background. Comminuted radial head fractures are challenging to treat with open reduction and internal fixation. Complicating matters further, radial head fractures are often associated with other elbow fractures and soft tissue injuries. Radial head arthroplasty is a favorable technique for the treatment of radial head fractures. The purpose of this study was to evaluate the functional outcomes of radial head arthroplasty using Modular Pyrocarbon radial head prosthesis in patients with unreconstructible radial head fractures. Methods. This single surgeon, single centre study retrospectively reviewed the functional and radiological outcomes of 21 consecutive patients requiring radial head arthroplasty for unreconstructible radial head fractures between July 2003 and July 2009. Patients were at least one year post-op and completed a Short-Form 36 (SF-36) questionnaire, the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, and the Mayo Elbow Performance Index (MEPI). These patients were independently physically examined and their post-operative radiographs were independently reviewed. Results. 21 patients (9 males and 12 females) were reviewed at a minimum of 12 months follow-up. The mean DASH score was 10.8 (0-34.1), the mean SF-36 physical score was 76.9 (35-96), the mean SF-36 mental score was 83.8 (60-94), and their MEPI score was 86.4 (70-100). Patients maintained 90% of their grip strength in their injured arm when compared to their un-injured arm and had 17. o. of fixed flexion in the affected arm. Radiologically, 14 cases had some degree of post-traumatic osteoarthritis, 12 cases had evidence of heterotrophic ossification, 5 had some evidence of periprosthetic lucency and 3 of our cases were radiologically but not functionally ‘overstuffed’. Conclusion. Radial Head Arthroplasty with Pyrocarbon Radial Head Prosthesis is a safe and effective option when treating unreconstructable comminuted radial head fractures yielding good functional and radiological outcomes and remains the treatment option of choice at our institution

Trapeziometacarpal arthritis is a common condition, causing symptoms in up to ten percent of women and one percent of men¹. LRTI is the most commonly used surgical technique for this condition however, long-term studies have shown persistent weakness of pinch strength² after surgery. The Ascension® PyroDisk is a pyrocarbon disk shaped implant designed to articulate against the trapezium and metacarpal, preserving the height of the articulation. The objective of this study was to determine whether treatment with a pyrocarbon implant resulted in comparable pain relief and range of motion, whilst providing superior gains in pinch strength when compared to LRTI. This is a prospective randomized control trial comparing pyrocarbon implant to LRTI. Surgeries were accomplished by a single surgeon in a standardized fashion. Patients were evaluated at six weeks, three, six and 12 months following surgery. Data on pain (VAS), function (Patient Rated Wrist Evaluation (PRWE)), mobility and strength (grip, key and lateral pinch) were obtained as well as radiographic assessment of the height of the arthroplasty space. A total of 80 patients had surgery between July 2008 and November 2016. Forty patients were allocated to the PyroDisk group and 40 to the LRTI group. Seventy-four patients (92,5%) completed the one year follow-up. Mean age was slightly older in the PyroDisk group (64 vs 60,8 y.o., p=0,03). Surgical and tourniquet times were longer in the PyroDisk group. There was no difference between the groups in strength, pain or functional outcome at one year. However, VAS was significantly higher in the PyroDisk group at three and six months (4,5 vs 2,4, p < 0,001, 2,6 vs 1,7, p=0,02) and PRWE was also significantly better at three months in the LRTI group (53,7 vs 71,2, p=0,02). The overall complication rate was three times higher in the PyroDisk group (10% vs 30%). Treatment of trapeziometacarpal arthritis with PyroDisk does not provide superior functional gains when compared to LRTI. On the contrary, it seems to result in more pain in the first few months following surgery. This difference in pain is not seen at 1 year after surgery. This may suggest that there is a period of adaptation to the Pyrodisk after its insertion. We also found a higher risk of complications with the use of the PyroDisk