Description
Objective
Medial patellofemoral ligament (MPFL) reconstruction has become a popular surgery for the treatment of patellofemoral instability. Patients report satisfaction and lower dislocation rate, with good results at mid-term. In literature, there are no studies reporting the long-term outcomes after MPFL reconstruction.
Matherials
A retrospective study was designed including all patients submitted to MPFL reconstruction between 2008 and 2013. Demographic and clinical data were collected, namely age, gender, number of dislocations, and revision surgery. Pre-operative patellofemoral (PF) relations measurements were assessed through computed tomography scan. After a minimum of ten-year follow-up period, patients were evaluated by magnetic resonance image, in which the PF indexes, chondral injuries, and trochlear dysplasia (according to Dejour classification) were assessed. Functional evaluation was also performed according to Kujala and Tegner Lysholm score.
Results
Data from 23 patients was gathered. The median follow-up time was 12 and a half years. At the time of surgery, the mean age was 18 ± 5 years and most of the patients were female.
A positive correlation was found between tibial tubercule-trochlear groove (TT-GT) distance in pre and postoperative imaging exams (16,20 IQR 13,75-18,3 VS 20 IQR 18-21 mm, r= 0,513), and it was independent of skeletal maturity and gender.
Comparing pre and postoperative exams, a negative strong correlation was found between subluxation in 0º of extension (1,57 IQR 0,81-4,30 VS 1 IQR 0-3,75 mm, r=-0,591) and with contraction (1,66 IQR 1,2-7,35 VS 5 IQR 0,62-8 mm, r=-0,106). Parallelly, a significant and positive correlation was found between tilt in 0º of extension (24 IQR 15-29,5 VS 15 IQR 6-5-26,75 mm, r=0,698, p=0,025) and with contraction (32 IQR 26-41 VS 22,5 IQR 9,25-37,5 mm, r=0,650, p=0,081).
Around 40% of the patients had a concomitant Ficat surgery. Despite not being statistically significant, these group presented with higher tilt values in preoperative study and had a slightly higher decrease in the tilt value in the postoperative exams, compared to the ones that did not have this additional surgery.
We had 2 cases of dislocation and only one was submitted to revision surgery, with additional anterior tibial tubercule osteotomy. Both were skeletally immature patients on admission.
Around 50% presented with chondral injuries type 3 and 4, mostly located on the lateral facet of the rotula. No correlation was found between the presence of these lesions and actual age (p=0,726), gender (p=0,148), or TT-GT distance (p=0,450). Despite no statistically significant (p=0,313), chondral injuries grade 4 were only found in patients with trochlear dysplasia C and D.
The median Kujala Score was 89 IQR 81,25-96,75 and the median Lysholm was 86 IQR 76.75-94,75.
Conclusion
According to our data, MPFL reconstruction appears to have good clinical long-term results. Furthermore, it seems that the desired restrain effect remains effective. However, this procedure seems insufficient to correct maltracking alignment. Our re-dislocation rate was around 8%, which is slightly superior to what is reported in literature, considering that this can be related to the sample size.
