Outcomes After Isolated Medial Patellofemoral Ligament Reconstruction for the Treatment of Recurrent Lateral Patellar Dislocations.

Schneider DK, Grawe B, Magnussen R5, Ceasar A, Parikh SN, Wall EJ, Colosimo AJ, Kaeding CC, Myer GD. Am J Sports Med. 2016 Nov;44(11):2993-3005. [Link to free full text article]

This is the editor's interpretation of a paper published in the orthopaedic literature in 2016 - our attempt to make relevant medical articles accessible to lay readers. If you wish to read the original it is easy to ask your librarian to obtain a reprint for you from any medical library.

This paper gives the findings of a Review and Meta-analysis of published literature relating to people who had suffered a patellar dislocation which was not initially managed surgically, but who was then subsequently troubled with patellar instability and operated on with a medial patellofemoral ligament (MPFL) surgical reconstruction alone.

The authors explored and evaluated >1000 abstracts in the published medical literature, referenced these against a checklist of criteria, and then chose 14 articles to explore in depth. The checklist excluded patients with obvious mechanical problems - such as trochlear dysplasia and marked mal-alignment - as possible causes of the dislocation.

This review aggregates their findings of those 14 articles. The purpose of their study was to identify what kind of patient was generally selected for this procedure of isolated MPFL reconstruction, and then to determine the eventual outcomes of this surgery, particularly in repect of stability and return to sports. References for the 14 key articles are give, so you can easily access the source literature.

The initial paragraphs of the paper discuss their research methodology, and they themselves admit that there were difficulties in he research, but we will just consider their main findings.


Main points that the authors raise

They note that patellar dislocations are common in young athletic individuals - 43 cases per 100,000 youngsters - and the incidence peaks at about 15 years of age. Nearly 70% of the initial patellar dislocations occurred during sporting activities.

Management used in the past to be primarily non-surgical - but the authors note that nowadays, although initial management is still generally non-operative, if the conservative (or non-surgical) regime fails and re-dislocation occurs doctors are more and more referring patients to the surgeons early rather than continuing to follow the conservative route. The surgery chosen for the initial surgical stabilisation of a recurrent dislocation is more and more that of medial patellofemoral ligament (MPFL) surgery - and their review suggests a mean age of 24.4 years for this first MPFL reconstruction.

The reviewers feel that, in the right patient group, such isolated MPFL reconstruction is effective at re-establishing and maintaining patellofemoral stability. By 'right patient group' you must note that these studies generally excluded patients with marked trochlear dysplasia, a TT-TG distance of >20mm and a marked J-sign - which patients would generally require careful evaluation and probably more than just this one procedure.

When discussing the potential for complications, they felt that an important technical consideration is the location of femoral tunnel placement. Although they noted that non-anatomically placed femoral tunnels do not necessarily correlate with poor outcomes, tunnels placed both proximally and/or anteriorly (high and towards the front) increase strain on the graft and may increase the potential for graft failure. Another unwanted complication is patellar fracture and again they point out that there are technical considerations that might minimise this risk, such as avoiding transpatellar tunnels.