The ProV3.8 system monitors the amount of physical activity a patient is doing and compares this to researched norms for similar patient types, both in the months leading up to surgery and during the rehabilitation period that ensues.
This should help orthopaedic surgeons and family doctors to provide the most suitable care for patients.
Ian Revie, chief executive officer of Activ4Life, which developed the system, said that it brings an "additional dimension" to hip and knee surgery care.
"The visibility of patient activity and pain trends over time will help inform the patient, GP and surgeon of the optimal time for surgery. Moreover, potential problems in rehabilitation can be identified early and acted on," he explained.
The device, which is worn under the patient's clothes, is currently being trialled in two UK hospitals.
Patients who choose to undergo private knee replacement surgery in a UK hospital can expect to pay in the region of £8,000 to £10,000.