2015 ISAKOS Biennial Congress Paper #0

Do Pyrocarbon Radial Head Replacements Offer Satisfactory Clinical and Radiological Outcomes? A Systematic Review

Atif Ayuob, MBBS, MRCS, ChM, Worcester UNITED KINGDOM
Zain ur-Rahman, MBBS, FCPS, Worcester, Worcestershire UNITED KINGDOM
Robert Jordan, MB BS, MSc, FRCS (Tr&Orth), Birmingham UNITED KINGDOM
Simon Maclean NEW ZEALAND
Peter Alberto D'Alessandro, MBBS Hons. (UWA) FRACS FAOrthA, Claremont, WA AUSTRALIA
Shahbaz S Malik, BSc, MB BCh, MSc (Orth Engin), LLM, FRCS (Tr&Orth), Birmingham UNITED KINGDOM
Worcestershire Royal Hospital, Worcester, Worcestershire, UNITED KINGDOM

FDA Status Cleared

Summary: Theoretically pyrocarbon promises to be a superior material for radial head arthroplasty due to its high biocompatibility with the bone. The primary objective of this systematic review was to evaluate clinical and radiological outcomes of Pyrocarbon radial head replacements.

Abstract:

Background

Pyrocarbon promises to be a superior material for radial head arthroplasty due to an elastic modulus comparable to the native bone and thus providing higher biocompatibility. The primary objective of this systematic review was to synthesize available literature investigating the clinical and radiological outcomes of Pyrocarbon radial head replacements while the secondary objective was to determine the complications and revision rates related to the usage of these prostheses.

Methods

Three electronic databases (PubMed, Medline, EMBASE) were used to search for studies published on outcomes and complications of the radial head arthroplasties using Pyrocarbon radial head prostheses. The systematic review was designed in accordance with the PRISMA guidelines and the review was registered prospectively in the PROSPERO database. The studies were appraised and scored using the Methodological Index for Non-Randomized Studies (MINORS) tool. To ensure repeatable results, the database searches were performed independently by two authors on two separate occasions. Functional outcomes were assessed objectively using different PROMs like MEPS, DASH and BMS (Broberg-Morrey Score). Range of motion was measured using goniometer and grip-strength was measured using the dynamometer. Post-operative radiological outcomes were reported using radiographs.

Results

A total of 13 studies cumulatively reporting 330 patients who underwent Pyrocarbon radial head arthroplasty were included in the review. The mean age of patients ranged from 47 years to 54 years of which 51.1% were males. The majority of radial head replacements were done for acute trauma (86.6%; 297/343) with the remainder done for arthritis (1.5%) and trauma sequelae (11.9%). Mean follow-up period in the selected studies ranged from 18 months to 110 months with minimum follow-up across all studies being 12 months. MoPyC (Modular Pyrocarbon, Tornier™, Montbonnot-Saint Martin France) was the implant of choice in twelve studies while one study used the Ascension Pyrocarbon radial head (Ascension Orthopaedics™, Austin, TX). Nine studies demonstrated mean Mayo Elbow Performance Score (MEPS) ranging from 79.5 to 96. Mean extension deficit across twelve selected studies ranged from 6 to 19 degrees while mean flexion ranged from 120 degrees to 140 degrees. Mean pronation and supination ranged from 71 degrees to 87 degrees and 63 degrees to 85 degrees respectively. Seven studies reported grip strength, ranging from 68.9% to 96% of the grip strength in the contralateral limb. Overall implant-related revision rate due to intra-prosthetic dissociation, prosthetic fracture, peri-prosthetic loosening, radio-capitellar subluxation and under-stuffed/over-stuffed elbow was 6.4% (21/330). Radial stress shielding and peri-prosthetic lucency was seen on radiographs in 6% to 100% of patients across different studies but symptomatic implant loosening leading to revision remained rare (1.5%, 5/330). Radiological radio-capitellar congruence was reported in 81% to 100% cases across different studies while capitellar erosion ranged from 0% to 89%. Pyrocarbon implants specific complications included implant fracture in 1.5% cases and intra-prosthetic dislocation in 1.2% cases.

Conclusion

Mid-term to long-term clinical and radiological outcomes and revision rates of pyrocarbon radial head replacements are satisfactory, but implant specific complications like intra-prosthetic dissociations of modular implants and pyrocarbon fractures must be kept in mind when choosing for these implants.