Best option for total hip replacement in young: evidence from National Joint Registry of  United Kingdom and Australian Orthopaedic Association National Joint replacement Registry

Introduction Implant longevity is crucial in determining the clinical success of THA. Hence THA in young patients will need a careful consideration as the failure and revision rates of THA are higher due to high functional demands. Method Reviewed the latest evidence from the 17th annual report of National Joint Registry (NJR) of United Kingdom and the 2020 annual report of Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) to determine the optimal mode of fixation, bearing surface and the head size for THA in a patient before the age of 55 years. Results In THA of patients under 55 Years, the 10 Year RR was highest in Uncemented fixations compared to other modes but this difference is insignificant according to the AOANJRR. Uncemented and hybrid fixations were preferred over cemented fixations but uncemented was clearly the predominant mode of fixation and this preference was rising over the past years. COC and COP bearing surface combinations reported to have the lowest 10 YRR and the use of COP in young patients has been rising both in UK and Australia in the recent past. In COC the head size of 40mm showed the best survival rate and in COP 36mm was the largest size with better survival. In COP the increased quality with XLPE (ultra-high molecular weight polyethylene) has been the reason for the ability use a larger head size with low dislocation rates better survival with low wear compared to Non XLPE used in the past. Conclusion Both Registries favour the use of Uncemented or Hybrid fixations with COC and COP bearings in patients <55 years and COC and COP bearings were compatible with best survival rates. Improved wear resistance with modern XPLE has been the reason for better survival with COP and the ability to use larger head size like in COC, reducing the risk of dislocations. Uncemented /Hybrid fixation with COC with 40 mm head size or modern XLPE COP with 36mm head size would be the best choice for a THA in a patient <55 years of Age.