A pilot study was performed to assess the feasibility of discharging patients undergoing unicompartmental knee replacement (UKR) within a day of surgery; both clinical and administrative issues were examined.

Logistics and responsibilities were organised prior to the study. Representatives of anaesthetics, pain team, orthopaedics, admissions, bed management, nursing, theatres, physiotherapy, radiology and outpatients were involved. Patients with medial compartment osteoarthritis undergoing unicompartmental knee replacement who passed strict exclusion criteria were recruited. Factors included; unsuitable home situation (no phone, excessive stairs, no support person), low tolerance to NSAIDS, and not living within a 25 mile radius of the hospital. To date seven NHS patients (mean age 60 years) have been recruited. All patients underwent preoperative assessment and counselling. The mean preoperative Oxford Knee Score was 24/48, the mean Knee Society Score (KSS) was 43/100 and average pain score was 14/50 indicating all patients had significant dysfunction and pain before operation. Average knee flexion was 111° and the average flexion deformity was 5°.

Each patient had a medial UKR using the minimally invasive approach and then underwent the accelerated recovery program. The program included pain control, accelerated rehabilitation, dedicated instructions and self assessment. Post operative pain was controlled by an intra-operative infiltration of local anaesthetic around the knee and large doses of NSAIDs. All patients were mobilised on the day of surgery and all except one who was delayed for administrative reasons) were discharged the following day. Patients were discharged in an extension splint and provided with post operative instructions including an emergency back up telephone number. A designated clinician made regular contact with the patient at home to assess progress. Patients were then assessed in clinic at 6 days, 13 days, and 6 weeks after surgery.

Patients average pain scores at 7 days and 14 days were 2/10 and 2.2/10 respectively. At 6 week follow up the average knee flexion was 124° and average flexion deformity was 1°. All patients were walking independently and painfree. No complications were encountered except one patient required further manipulation for limited knee flexion.

The new pain control protocol permits early mobilisation and discharge for patients undergoing UKR. Potential benefits include increased patient comfort, functional rehabilitation, avoidance of hospital induced infection and substantial cost benefits to the NHS. The pilot study demonstrates that, provided adequate communication is maintained between involved personnel, the program is both practical and safe. It now is planned to implement the accelerated recovery program for UKR as routine.