Injuries Associated with Anterior Dislocations.
Last updated Tuesday, February 01, 2005
Recurrence of instability after anterior dislocatiEffect of age The age of the patient at the time of the initial dislocation has a
major influence on the incidence of redislocation. (Rowe, 1956; Rowe
and Sakellarides, 1961) Several authors have reported that individuals
under the age of twenty at the time of the initial dislocation have up
to a 90% chance of having recurrent instability. (Arciero et al, 1994;
Henry and Genung, 1982; Hovelius, 1987; Hovelius et al, 1994; Kiviluoto
et al, 1980; McLaughlin and Cavallaro, 1950; McLaughlin and MacLellan,
1967; Moseley, 1961; Rowe, 1956; Simonet and Cofield, 1983; Wheeler et
al, 1989) Over the age of 40 the incidence drops sharply to 10 to 15
per cent. (McLaughlin and MacLellan, 1967; Rowe and Sakellarides, 1961)
Hovelius et al(Hovelius et al, 1996) reported a careful prospective
study with somewhat lower incidences of recurrences in each age group:
33% under 20, 25% between 20 and 30, and 10% between 30-40 years. The
majority of all recurrences occur within the first two years after the
first traumatic dislocation. (Adams, 1948; Bankart, 1939; DePalma,
1973; Eyre-Brook, 1943; McLaughlin and Cavallaro, 1950; Moseley, 1945;
Moseley, 1963; Rowe, 1956; Rowe, 1978; Townley, 1950)
Effects of trauma, sports, gender, and dominance Rowe (Rowe, 1956; Rowe and Sakellarides, 1961) has pointed out that the
recurrence rate varies inversely with the severity of the original
trauma; in other words, the more easily the dislocation occurred
initially, the more easily it recurs. The recurrence rate among
athletes may be higher than non athletes (Simonet and Cofield, 1983)
and higher among men than women (Moseley, 1961). Dominance of the
affected shoulder does not seem to have a major effect on the
recurrence rate. (Rowe and Sakellarides, 1961)Effect of post dislocation treatment In many reports, the incidence of recurrence appears to be
relatively insensitive to the type (sling vs. plaster Velpeau) and
duration of immobilization (0 vs. 4 weeks) of the shoulder following
initial dislocation. (Ehgartner, 1977; Hovelius et al, 1983; McLaughlin
and Cavallaro, 1950; Rowe and Sakellarides, 1961)
By contrast, others have reported that longer periods of
immobilization (over three weeks) are associated with a reduced
incidence of recurrence. (Kazar and Relovszky, 1969; Stromsoe et al,
1980)
In a definitive 10-year prospective study, Hovelius et al studied
the effect of immobilization on the incidence of recurrence. (Hovelius,
Augustini, Fredin et al, 1996) After reduction, 247 primary anterior
dislocations were partially randomized to either a 3-4 week period of
immobilization or to a sling to be discarded after comfort was
achieved. The authors concluded that the immobilization did not affect
the rate of recurrence. The results provide useful 'rules of thumb':
overall half of these shoulders had recurrent dislocations; half of the
recurrences had surgical treatment; half of the recurrences treated
nonoperatively were stable without surgery at 10 years. One of six
patients had dislocation of the opposite shoulder. Eleven percent of
the shoulders had at least mild evidence of secondary degenerative
joint disease. Interestingly, this secondary DJD was observed in both
surgical and nonsurgical cases.
Aronen and Regan (Aronen and Regan, 1984) reported a three year
average followup study on 20 primary dislocations in Navy midshipmen
treated with a three month aggressive post dislocation program. The
program consisted of three weeks of sling immobilization followed by
progressive strengthening. The patients were not allowed to return to
activity until there was no evidence of weakness or atrophy and no
apprehension on abduction and external rotation. In this series there
were no recurrent dislocation and two recurrent subluxations.
Similarly, Yoneda, (Yoneda et al, 1982) reported good results in 83% of
patients in a program emphasizing post immobilization exercises.
The effect of fractures The incidence of recurrence is lower when a first-time shoulder
dislocation is associated with a greater tuberosity fracture. (DePalma,
1950a; Hovelius, 1987; Hovelius, Augustini, Fredin et al, 1996;
McLaughlin and MacLellan, 1967; Roston and Haines, 1947; Rowe, 1956;
Rowe, Pierce and Clark, 1973) Hovelius (Hovelius, 1987) reported that
these fractures were four times as common in patients over 30: 23%
compared with 8% among patients under 30.
Other fractures, such as substantial posterior lateral humeral head
lesions and fractures of the glenoid lip are likely to be associated
with an increased incidence of recurrent instability.
In conclusion, it appears that the injuries sustained by young
patients in association with traumatic dislocations are relatively
unlikely to heal in a manner yielding a stable shoulder. Probably the
most important of these unhealing injuries are:
- the avulsion of the glenohumeral capsular ligaments from the anterior glenoid lip, and
- the posterolateral humeral head defect.
Older patients may tend to stretch the capsule or fracture the
greater tuberosity, either of which is likely to heal yielding a stable
shoulder. In atraumatic instability, there is no traumatic lesion and
thus a high chance of recurrence. The degree of trauma and the age of
the patient seem to be the most important factors in determining the
recurrence rate.
Disclaimer
This resource has been provided by the University of Washington Department of Orthopaedics and Sports Medicine as general information only. This information may not apply to a specific patient. Additional information may be found at http://www.orthop.washington.edu or by contacting the UW Department of Orthopaedics and Sports Medicine.
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