The need for a more durable, metal free, non-osteolytic particle generating material in Total Hip Replacement (THR) is urgently required to reduce revision surgeries. Current used materials; ceramic, metal and UHMWPE remain discrepant for long-term use. Polyimide (MP-1™) is a high performance biopolymer, originating from aerospace industry. MP-1™ is heat resistant, highly cross-linked and exhibits a self-lubrication property required for bearings and articulating joints. Being resistant to fatigue, creep and chemicals and serializable by autoclave or irradiation, MP-1™ is ideal for medical devices.

Finalizing pre-clinical testing, two patients were implanted 13 years ago after informed consent. A PM (Post Mortem) retrieval at 6.5 years, showed no measureable wear, a bland synovium, and no osteoclastic or bone marrow reaction. The 13Y patients' hip, a revision from Polyethylene wear to MP-1™, has an unchanged radiograph and is fully active (Fig. 1).

The Ethical Committee approved 100 patients with a single surgeon (PJB) post-marketing trial running Delta ceramic femoral ball against MP-1™ liner. Age range is from 81 to 33 years. The younger patients now being offered MP-1™, in view of the retrieval data. The MP-1™ acetabular liner is 4mm thick, as currently used in a LIMA PF shell, which replaces polyethylene, ceramic or dual mobility options.

Out of the 78 enrolled patients, 52 patients have the implant for more than 5 years. The only “Complications” in a few patients was an initial squeak which spontaneously disappears by 10 days and never returns. This is likely due to reduced clearance between head and liner and likely easily correctable. There have been no dislocations or restrictions on activity level. Oxford and Harris Hip scores along with radiology, blood and clinical examination are collected during follow-up.

MP-1™ liner on Delta ceramic head in THA, or in the future with MP-1 head, looks very promising with advantages of ease of sterilization, insignificant wear, no tissue reactivity and ability to have thin section and larger femoral heads if desired for larger range of motion.

MP-1™ biomaterial is used for other medical devices as well such as dental implants and trauma nails, plates and screws.

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Aim: In 1990 the Christchurch Hospital Sarcoma Clinic established management guidelines for patients with suspected sarcomas, recommending referral prior to investigation, biopsy and excision. The aim of this study was to determine whether these guidelines are being followed.

Method: A review of the case notes of all sarcomas referred to the Sarcoma Clinic between 1990 and 1999 was performed.

Results: There were 53 referrals, 34 (22%) from orthopaedic surgeons, 56 (37%) from general surgeons, 16 (10%) from general practice and 47 (31%) from other specialties. Only 83 (54%) of the referrals had followed the guidelines. Twenty-five (74%) of the orthopaedic referrals, 19 (34%) of the general surgical, 10 (63%) of the general practice and 29 (62%) of the other specialties had followed the guidelines. Seventy (46%) of the referrals had failed to follow the guidelines. Thirty-four (49%) of these had undergone excision inadequate for sarcoma prior to referral, of which eight had been re-excised. Twenty-four patients had not been staged prior to excision despite having a positive fine needle aspiration (FNA) in four cases. Eighteen patients (26%) had FNA or biopsy prior to imaging or referral.

Conclusion: Forty-six percent of sarcoma patients had not been treated according to the recommended guidelines. Forty-nine percent of these had inadequate primary sarcoma excision and this may have compromised their outcome. Orthopaedic surgeons had the best record for following the guidelines at 74% of referrals but this could be further improved. Doctors and especially surgeons need to be more aware of the principle of early referral of patients with suspected sarcomas.