End-stage haemophiliac arthropathy can be successfully treated with total knee arthroplasty. However, the functional results may not be as good as anticipated and certain pre-op knee characteristics may alter the functional results. The purpose of this study was to evaluate the functional outcome of TKA in haemophilic patients with specific attention to final range of motion and residual flexion contracture of the joint. Twenty-one consecutive patients were retrospectively reviewed. The average age was 34 years with an average follow-up of 5.7 years. Functional status was evaluated with Hospital for Special Surgery Knee Score. Receiving Operating Characteristics analysis was used to determine the threshold of pre-operative flexion contracture degree to avoid residual knee contracture. The range of motion was increased in 16 joints and unchanged in three joints and decreased in the remaining two. Preoperative average range of motion was 37.6 degrees, improved to 57.1 degrees post-operatively. The average knee score increased from 27.85 (1530) points pre-operatively to 79.42 (1294) points at the last follow-up. The degree of pre-operative flexion contracture was found to be a good predictor for residual flexion contracture. (Specificity: 85.7%, sensitivity: 100%, cut-off: 27.5 degrees). Total knee replacement improves the quality of life in patients with advanced haemophilic arthropathy. Statistical analysis revealed that pre-op flexion contracture of 27.5 degrees is an important threshold. Patients should be operated before that stage to gain maximum benefit with minimal gait abnormalities.