Shoulder injuries are pretty common, but there is one that is especially frustrating because it seems to come on out of no where, frozen shoulder. Frozen shoulder is known in the medical field as adhesive capsulitis and presents as a loss of range of motion (ROM) with no known cause. This definition is quite broad and many people fall into this category. Many researchers and physicians have recently reported that rotator cuff (RTC) injuries can be quite common with frozen shoulder and some even believe that a RTC injury may be the cause of a frozen shoulder. However, due to the vagueness of the definition many studies about frozen shoulder use very different criteria for the loss of ROM, and this makes these studies hard to compare. This study by Ueda et al hopes to clarify the symptoms of people with frozen shoulder who also have a rotator cuff injury.
This study consisted of 379 shoulders of patients with stiff shoulders with no trauma, diabetes or other abnormalities. Their ROM was measured in standing and lying down and the shoulders were divided into three groups. Group 1 had severe and global loss of motion in all three directions, less than 100 degrees of forward flexion, less than 10 degrees of external rotation and internal rotation reach no higher than the level of the 5th lumbar vertebra. Group 2 had severe limitation in at least one of the three directions, but not in the other two. The 3rd group included all the remaining shoulders with mild to moderate limitation. These shoulders were then imaged with MRI or ultrasound to determine if there was injury to the RTC.
Group 1 had eighty-nine stiff shoulders with mean ROM measurements of forward flexion of 88 degrees, external rotation of 1 degree and internal rotation reach just to the buttock level. The imaging studies showed that ninety-one percent had no injury to the RTC and nine percent had a partial tear. There were no full thickness tears in this group at all.
Group 2 consisted of 111 stiff shoulders with mean ROM measurements of 130 degrees of forward flexion, 31 degrees of external rotation, and internal rotation reach to the 5th lumbar vertebra. The imaging results of this group showed forty-four percent normal RTC, seventeen percent partial-thickness tear and thirty-nine percent had a full thickness tear of the RTC.
Group 3 included 179 stiff shoulders with mean ROM measurements of 154 degrees of forward flexion, 49 degrees of external rotation and internal rotation reach to the 12th thoracic vertebra. The imaging studies showed thirty-five percent normal RTC, sixteen percent partial tear, and fifty percent with a full thickness tear in the RTC.
The results of this study indicate that if there is global and severe loss of motion with a stiff shoulder, then it is not likely that there is a rotator cuff injury. However if there is loss of motion in only direction, but not as severe in the others, or only minimal loss of motion in all directions there can be up to a 50 per cent chance of a full thickness rotator cuff tear. In this case, getting imaging such as an MRI to look at the RTC is appropriate.