Monoblock hemiarthroplasties for femoral neck fractures--a part of orthopaedic history? Analysis of national registration of hemiarthroplasties 2005-2009.

This study from the Swedish Hip Arthroplasty Register (SHAR) compares cemented (Thompson(®), Exeter Trauma Stem (ETS)(®)) and uncemented (Austin-Moore(®)) monoblock hemiarthroplasties (n=1116 and 616, respectively) with modular ones (n=18,659). Austin-Moore(®) prostheses lead to more re-operations (6.7%) compared to modular implants (3.5%) and Thompson(®)/ETS(®) (2.4%). A Cox regression analysis, adjusting for other risk factors, shows twice the risk of re-operation for Austin-Moore(®) implants (CI 1.5-2.8), in particular, due to periprosthetic fracture (5.4; CI 3.2-9.1) and dislocation (1.9; CI 1.3-3.0). The Thompson(®)/ETS(®) implants do not influence the overall risk of re-operation (0.7; CI 0.5-1.2) compared to modular implants and decrease the risk of re-operation due to infection (0.2;CI 0.04-0.7). An increased risk of re-operation is also seen in men, age groups 75-85 years and <75 years and after secondary fracture surgery. Both Swedish and Australian orthopaedic surgeons have decreased their use of Austin-Moore(®) implants after reports from their national arthroplasty registers identifying inferior outcome for this implant. Due to the increased risk of re-operations, it should not be used in modern orthopaedic care. Cemented Thompson(®) or ETS(®) implants could still be suitable for the oldest, low-activity patients. To finally decide if there is a place for them, patient-reported outcome must be analysed as well.