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Three Part Question

In [patients with primary patellar dislocation] is [surgery better than conservative treatment] in [reducing symptoms and preventing redislocation]?

Clinical Scenario

A 20 year old woman presents to the emergency department having suffered her first lateral patellar dislocation 1 hour before. She has managed to reduce it herself. You wonder whether surgery is superior to conservative management.

Search Strategy

Medline 1966-06/99 using the OVID interface.
[({exp patella OR patella$.mp} AND {exp dislocations OR dislocate$.mp OR dislocation$.mp}) AND {exp emergency treatment OR exp treatment failure OR exp treatment outcome OR treatment$.mp}] AND maximally sensitive RCT filter) LIMIT to human and english.

Search Outcome

79 papers found of which 74 irrelevant and 3 of insufficient quality for inclusion. The remaining papers are shown in the table.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Cash and Hughston USA 1988	103 primary patellar dislocations over 30 years. Conservative treatment (74) vs athroscopy (13) alone vs arthrotomy (16) Subanalysis predisposed to dislocate (69) vs no predisposition (34)	Retrospective cohort	Recurrence rate (more than 1 redislocation)	36.5% vs 23% vs 0	Retrospective non- randomised series over 30 years. Very small numbers in some groups.
			Recurrence rate (more than 1 redislocation) congenital predisposition vs none	Conservative 43% vs 20% Arthroscopy 0 vs 11% Arthrotomy 0 vs 0
Nikku R et al Finland 1997	125 patients with acute primary patellar dislocation. Conservative (55) vs operative (70)	PRCT	Instability (redislocation or subluxation)	No significant difference	Randomised by year of birth. Operations not standardised. All patients had EUA and arthroscopy prior to randomisation.
			Patient opinion	No significant difference
			Lysholm II score	No significant difference
			Hughston VAS	No significant difference
			Number of major complications	4 in operative group

Comment(s)

There are a great number of single treatment case series in this area. Only one comparative series is randomised, and the surgical treatment is not standardised in either series. There is a suggestion that outcome may be different if there is a predisposition to dislocate but the evidence for this is very weak. Further work is required.

Clinical Bottom Line

Conservative management of primary patellar dislocation is as effective as surgery and has a lower complication rate. It is the treatment of choice.

References

1. Cash JD and Hughston JC. Treatment of acute patellar dislocation. Am J Sports Med 1988;16:244-249.
2. Nikku R, Nietosvaara Y, Kallio PE et al. Operative versus closed treatment of primary dislocation of the patella. Acta Orthop Scand 1997;68:419-423.