Are there differences between Maori and non-Maori patients undergoing primary total hip and knee arthroplasty surgery in New Zealand? A registry-based cohort study.

AIM: It has been well demonstrated that Maori have the poorest health status of any ethnic group in New Zealand. The aim of this study was to determine whether there are any differences between Maori and non-Maori patients in the severity of their arthritis preoperatively and in their postoperative functional outcomes following primary total hip and knee arthroplasty surgery. Secondary objectives were to compare general and mental health scores and to determine whether the intervention rate for Maori arthroplasty patients is appropriate.

METHOD: We compared preoperative and postoperative (1 and 5 year) Oxford and WOMAC scores, general health (SF-12 PH) and mental health (SF-12 MH) scores in all public patients who underwent primary total hip and knee arthroplasty surgery in our region between 2005 and 2009.

RESULTS: Maori patients are younger at the time of surgery, have higher ASA scores and worse preoperative function. They also have worse postoperative outcomes and smaller overall improvements following surgery when comparing their preoperative with postoperative scores. In terms of general health, Maori and non-Maori had similar SF-12 PH scores but worse SF-12 MH scores both pre- and postoperatively.

CONCLUSION: Maori patients are younger, have worse general and mental health and worse preoperative function compared with non-Maori patients. Both absolute and differential scores show that Maori patients also have worse postoperative outcomes compared with non-Maori patients. These differences are likely clinically significant and ongoing education and effort is required in order to achieve earlier intervention rates and improve postoperative outcomes for Maori patients.