The knee cap (patella) can sometimes be a very unstable part of the knee. Several factors want to drag the knee cap laterally (to outside of knee) but this is resisted by the medio patellofemoral ligament (MPFL) on the medial side (inside half) of the knee cap.
When the patella dislocates to the outside of knee (usually with slight knee bending and rotation), the MPFL is torn. This causes pain and bleeding in the knee joint. If the knee cap does not return to normal position spontaneously, it needs to be relocated under sedation by a doctor.
Some predisposing factors make the patient more prone to dislocation/subluxation of patella:
After a first injury of the MPFL, it can be treated conservatively with rest, crutches and a brace for 6 weeks and about 70% of patients will stabilize completely. If still unstable after conservative treatment or in patients with above predisposing factors, a MPFL reconstruction with a hamstring tendon can be done. It will heal in 6 weeks and return to sport will be at 3-6 months. If the patient has patella alta, a concomitant tubercle osteotomy should also be done whereby the patella position is lowered. This will need longer recuperation before sport of 6 months.
Suite 2 West Coast Private Hospital,
22 Voortrekker Street
Vredenburg, 7380
