Background: knee arthritis is a risk factor for falling. Increasing numbers of people are receiving total knee arthroplasty (TKA) but the natural history of falling before and after TKA is unknown.

Objective: to prospectively monitor falls in pre- and post-operative TKA patients and to identify independent risk factors for post-operative falling.

Design: a prospective observational study with a 1-year follow-up.

Participants: community-dwelling older people recruited from a regional orthopaedic centre.

Methods: consecutive patients added to the TKA waiting list who completed monthly falls diaries, pre-operatively and 1 year post-operatively. Data on knee status (WOMAC: pain, stiffness and function), balance confidence (the Activities Balance Confidence Scale-UK—ABC-UK) and mood (Geriatric Depression Scale—GDS) were collected at quarterly intervals.

Results: ninety-nine patients received a primary TKA. 24.2% fell in the last pre-operative quarter (24 patients reported 44 falls) and this decreased to 11.7–11.8% in the first four post-operative quarters. 45.8% of people who fell pre-operatively fell again in the first post-operative year. Higher pre-operative GDS scores and a history of falling were significant independent predictors of post-operative falling.

Conclusion: a recent history of falling is common in people undergoing TKA and 45% of patients fall again in the year following surgery. Patients being considered for TKA should be asked about falls history and undergo falls risk assessment and intervention.