What is the Donjoy 4 Titude Knee Brace? Ideal for rehabilitation of all knee ligament & cartilage injuries for active, sedentary & adolescent patients. Also ideal for support when returning to sports. When can I use it? Provides protection during rehabilitation following MCL, LCL, PCL or ACL injury or surgery Knee support during rehabilitation following surgery for a torn cartilage Knee support during sports activities ACL, PCL & Combined Instability versions available (indicate version when ordering) One-year warranty on frame & hinge. What size is it? State left or right knee. Measure around the thigh, 15cm (6") above the kneecap. If you are between sizes, please choose the larger size. X-Small 33-39cm (13-15½") Small 39-47cm (15½-18½") Medium 47-53cm (18½-21") Large 53-60cm (21-23½") X-Large 60-67cm (23½-26½") XX-Large 67-75cm (26½-29½") XXX-Large 75-82.5cm (29½-32") How does it work? The Donjoy 4 Titude Knee Brace features the Donjoy Four Points of Leverage® system which will make your knee joint feel stable by providing control over extension & flexion of the knee joint. With a low profile, lightweight design, this knee brace has mouldable cuffs for a custom fit & removable thermal-formed liners & strap pads for unbelievable comfort. Please Note if buying from abroad: These products are sent direct from the manufacturer & so lead times will be significantly longer than normal if you purchase this item from outside the UK