The fate of the acromioclavicular joint in athletic injuries.

Of 164 acromioclavicular joint injuries to midshipmen at the US Naval Academy between July 1973 and November 1978, 99 were Type 1, 52 were Type 2, and 13 were Type 3. Follow-up examinations revealed that 36% of Type 1, 48% of Type 2, and 69% of Type 3 patients had residual symptoms. Positive physical findings were present in 43% of Type 1, 77% of Type 2, and 100% of Type 3 injuries. Roentgenographic changes were noted in 70% of Type 1, 75% of Type 2, and 100% of Type 3 patients. This evaluation suggests aggressive treatment and rehabilitation are indicated in acute acromioclavicular injuries. Residual problems from Types 1 and 2 injuries are much more frequent than indicated in the literature. Symptoms in Type 1, but not in Type 2, injuries are directly related to the presence of positive physical findings. Roentgenographic changes are extremely common and are not correlated with symptoms. Treatment of Type 2 injuries with the acromioclavicular immobilizer resulted in fewer complications than symptomatic treatment.