The goal of this observational study is to generate Real World Evidence (RWE) on the device performance of the Polymotion Hip Resurfacing (PHR) system and its use in patients who have been implanted with the device for the treatment of hip osteoarthritis.

This study will assess the following endpoints:

• The survivorship of the Acetabular Cup (Kaplan-Meier estimate) through 2 years of follow-up.
• Radiographic success of the implanted cups, through quantitative motion analysis to assess migration of the acetabular cups.
• Absence of subsequent surgical intervention at the acetabulum of there operated hip.
• Absence of serious, device-related adverse events.
• Patient reported outcomes through Harris Hip Score and SUSHI - UCLA Hip Score questionnaires.

This is a retrospective and prospective study that will include a maximum of 70 patients who were implanted with the JointMedica Polymotion Hip Resurfacing (PHR) device in Canada, New Zealand and Australia.

Patients will be invited to consent to participate in this study, which will require their attendance of a follow-up standard of care visit to gather clinical data on the safety and performance of their index hip, undergo an x-ray imaging and complete two questionnaires to assess their functionality and outcomes.

Patient data will be entered into electronic data capture systems and x-rays will be submitted to a core imaging laboratory, MMI, for analysis to assess the state and position of their acetabular cup.

Inclusion Criteria:

• Age 21 or above at the time of the surgery.
• Have had the Polymotion Hip Resurfacing (PHR) (implanted between September 2020 to January 2025
• Written informed consent given by subject

Exclusion Criteria:

• There is no exclusion criteria for this study

Subjects that underwent hip arthroplasty procedure with the Polymotion Hip Resurfacing (PHR) System (V3.1 Cup design) between September 2020 to January 2025.

Subjects who have previously had the Polymotion Hip Resurfacing (PHR) System implanted at the sites will be contacted to give consent to participate in the collection of additional follow-up visits described within this protocol.