HIP RESURFACING: LEARNED LESSONS AFTER THE FIRST CONSECUTIVE 486 CASES WITH SIX YEARS FOLLOW-UP

Abstract

Introduction: Higher loosening rate, improvements in metalo n metal bearings and excellent immediate clinico-functional results related with current Standard total hip endoprosthesis, have suposed the rennaisance of the new hip resurfacing implants. In this work we present our experience the first 486 cases and minimal 5 years follow up.

Material and method: From July 2003 to December 2008 486 surface arthroplasties were implanted in our institution (4 bilateral) in 450 patients, 314 males y 136 females, mean age of 46,6 years (16 – 69). 9 BHR, 2 ASR, 3 ADEPT, 5 CORIN, 22 Mitch and 409 CONSERVE PLUS models were implanted. In 454 cases a modified Kocher-Langenbeck posterior approach and in 32 cases Hueter’s anterior approach were carried out. Surgical time, intraoperative bleeding and collected blood in drains, components orientation in AP radiographies, registered complications, Merle d’Aubigné, WOMAC and HHS clínico-funtcional scores were assessed. Statistical analysis was performed by means of chi-squared test and non – parametric tests.

Results: Mean surgical time was 1h 50’ (1h 15’ a 2h 30’), mean intraoperative bleeding 273,4 cc (210 – 360cc), drained blood 224,2 cc (180 – 380cc). During the first year 11 autodonated blood units were retransfused (during the first 5 months patients were encouraged for 1000cc. autodonation). Mean CCD angle was 139,7° (SD 130 – 147) and acetabular inclination 43° (SD 40 – 65°). There were 4 instances of femoral fractures during the first half year after surgery, which required conversiòn to a BFH total endoprosthesis, one too adducted cup (65°), which required only cup exchange. There was a very significant improvement in clinico-functional scores: MDA score improved from 12,9 pts. preoperative (11 – 14) to 17,4 at latest follow-up (15 – 18) (p< 0,001), WOMAC from 46,2 (19 – 67) to 93,2 (79 – 100) (p< 0,001) and HHS from 52,3 (range 42 – 60) to 96,7 (range 89 – 98) (p< 0,001). Main complications were 1 arterial femoral thrombosis, 1 deep venous thrombosis, 1 deep infection that required 2-stages exchange, 4 transient femoral pare-sia. Overall survivorship was 98,97%.

Conclusions: hip resurfacing implantation, when recommendations made by the first authors of these new models are properly carried out, provide excellent clinical-functional results, comparable to non cemented total hip implants, if not better. Longer follow up are required to assess more adequately these implants, although it will not probably mean in the majority of the cases any hip exchange of a standard THA in terms of morbidity and mid-longterm clinical-functional result. This assumption has been taken from our cases converted to a THA with BFH. For this reason we do think absolutely we dispose today a very promising implant for young adults with well stablished hip osteoarthritis.