Case 7: A 17-year-old ice hockey goalie injured her right knee during a game. She was trying to block a shot and felt her patella move out of place. She had immediate pain and swelling and was unable to continue playing. She has a large effusion and pain around the patella. She has discomfort along the medial retinaculum and a positive apprehension test. Ligament testing in stable although she can only flex to 60°. She has had one previous patellar dislocation and has a hypermobile patella on the left side.
Lateral patellar subluxations and dislocations are a frequent sports injury. Subluxations occur when the patella moves partially out of joint with instant relocation as opposed to dislocations where the patella comes fully out of joint and needs to be relocated. The mechanism of injury is usually a twisting/cutting maneuver or fall. Athletes may hear or feel a pop as their patella slides out of place and may remember this sensation of patellar movement. Immediate swelling of the knee along with pain surrounding the patella and the medial retinaculum (the tissue just medial to the patella that gets torn during dislocation) occurs. Athletes with hypermobile patellas or lateral tilt may be predisposed to patellar dislocations. Those with recurrent dislocations may have a positive apprehension test and may have subluxation or dislocation of their patella with range of motion of the knee. Radiographs may show a subluxation/dislocation or lateral tilt on sunrise views. Small fragments of the patella may be fractured with a dislocation.
Treatment consists of initial RICE for the first 48 hours followed by range of motion exercises to help decrease swelling. The key to long-term treatment is an aggressive daily rehabilitation program consisting of core body strengthening especially the hip abductors, along with hamstring and quadriceps flexibility. Icing for 15 to 20 minutes after activity and use of a patellar stabilizing brace can be helpful. McConnell taping can also help guide proper patellar movement during activity. Athletes usually can return to activity in 4 to 12 weeks depending on their motivation regarding rehabilitation.
Once a patella dislocates it becomes easier for the same mechanism to cause further dislocations. For this reason continued rehabilitation exercises for as long as the athlete plays sports is required. If no improvement after 6 months of physical therapy or continued patellar dislocations, surgical evaluation may be necessary.
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