BACKGROUND: The treatment of acute patellar dislocation in children
is controversial. Some investigators have advocated early repair of the medial
structures, whereas others have treated this injury nonoperatively. The
present report describes the long-term subjective and functional results of a
randomized controlled trial of nonoperative and operative treatment of primary
acute patellar dislocation in children less than sixteen years of age.
METHODS: The data were gathered prospectively on a cohort of
seventy-four acute patellar dislocations in seventy-one patients (fifty-one
girls and twenty boys) younger than sixteen years of age. Sixty-two patients
(sixty-four knees) without large (>15 mm) intra-articular fragments were
randomized to nonoperative treatment (twenty-eight knees) or operative
treatment (thirty-six knees). Operative treatment consisted of direct repair
of the damaged medial structures if the patella was dislocatable with the
patient under anesthesia (twenty-nine knees) or lateral release alone if the
patella was not dislocatable with the patient under anesthesia (seven knees).
All but four patients who underwent operative treatment had a concomitant
lateral release. The rehabilitation protocol was the same for both groups. The
patients were seen at two years, and a telephone interview was conducted at a
mean of six years and again at a mean of fourteen years. Fifty-eight patients
(sixty-four knees; 94%) were reviewed at the time of the most recent
follow-up.
RESULTS: At the time of the most recent follow-up, the subjective
result was either good or excellent for 75% (twenty-one) of twenty-eight
nonoperatively treated knees and 66% (twenty-one) of thirty-two operatively
treated knees. The rates of recurrent dislocation in the two treatment groups
were 71% (twenty of twenty-eight) and 67% (twenty-four of thirty-six),
respectively. The first redislocation occurred within two years after the
primary injury in twenty-three (52%) of the forty-four knees with recurrent
dislocation. Instability of the contralateral patella was noted in thirty
(48%) of the sixty-two patients. The only significant predictor for recurrence
was a positive family history of patellar instability. The mode of treatment
and the existence of osteochondral fractures had no clinical or significant
influence on the subjective outcome, recurrent patellofemoral instability,
function, or activity scores.
CONCLUSIONS: The long-term subjective and functional results after
acute patellar dislocation are satisfactory in most patients. Initial
operative repair of the medial structures combined with lateral release did
not improve the long-term outcome, despite the very high rate of recurrent
instability. A positive family history is a risk factor for recurrence and for
contralateral patellofemoral instability. Routine repair of the torn medial
stabilizing soft tissues is not advocated for the treatment of acute patellar
dislocation in children and adolescents.
LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions
to Authors for a complete description of levels of evidence.