MPFL reconstruction as single procedure holds high risk of failure

Investigators called for careful selection of patients for revision MPFL reconstruction.

Issue: May 2014

NEW ORLEANS — Reasons for revision surgery after medial patellofemoral ligament reconstruction include errors in patient selection, technical problems and non-consideration of additional risk factors, according to a study presented at the American Academy of Orthopaedic Surgeons Annual Meeting.

Identifying potential causes of failure in medial patellofemoral ligament (MPFL) reconstruction can help treat and prevent further complications, according to the investigators.

“Reconstruction of the medial patellofemoral ligament has become the treatment of choice for patients with patellofemoral instability with good results reported in the literature. However, with increasing popularity with the procedure, high complication rates of up to 26% have also been reported,” Manfred Nelitz, MD, of the Orthopaedic Specialty Clinic, in Oberstdorf, Germany, said. “The aim of the study was therefore to analyze the reason for failure and to evaluate the clinical outcomes of a small group of patients following revision surgery after unsuccessful primary medial patellofemoral ligament reconstruction.”

Preoperative assessments

Fourteen consecutive patients with unsatisfactory MPFL reconstruction underwent revision surgery; 9 women and 5 men. To assess the MPFL graft, trochlear dysplasia and the tibial tubercle-trochlear groove distance, researchers preoperatively examined the patients with physical examination, radiographs and MRI. Any sign of cartilage injuries, the VAS scores, the Kujala knee function scores and the International Knee Documentation Committee (IKDC) scores also were included in each patient’s evaluation.

Transverse MRI of the proximal trochlea demonstrates high-grade trochlear dysplasia as a main risk factor for failure of MPFL reconstruction.

Nelitz and colleagues analyzed each complication and performed appropriate operative treatment based on the technical or untreated anatomical risk factors identified.

At the time of the primary operation, the patients’ average age was 18.4 years and the average age at time of the MPFL revision was 20.7 years.

This figure illustrates the created proximal groove and fixation of the osteochondral flake held by a Vicryl tape after trochleoplasty in a patient with high-grade trochlear dysplasia.

Based on the study results, 7 patients experienced recurrent patellofemoral instability and four of these patients had severe trochlear dysplasia. Five patients reported medial retinacular pain with limited flexion. Investigators found anterior placement of the femoral tunnel in two patients and an over-tensioned MPFL in three patients. One patient had patellar fracture due to violation of the anterior cortical patellar bone and another patient experienced fracture of the cortical bridge of the patellar bone tunnels. Researchers detected concomitant excessive femoral anteversion in two patients and identified patellofemoral pain due to ICRS grade III or IV cartilage injury in three patients.

Improved clinical outcomes

According to study results, Kujala scores improved from 57 points to 80 points. The IKDC scores improved from 66 points to 83 points and VAS scores improved from 4 points to 2 points postoperatively. Overall, 88.4% of patients were satisfied or very satisfied with the revision surgery results.

“The overall results of the 14 patients showed an improvement of all outcomes,” Nelitz said, noting the improved clinical scores were statistically significant.

Researchers found one patient with high grade retropatellar cartilage injury who was unsatisfied after arthroscopic microfracturing.

“Reconstruction of the MPFL can yield successful outcomes, but errors in patient selection, technical problems and non-consideration of additional risk factors were found to be the major reasons for revision surgery after MPFL reconstruction,” Nelitz told Orthopaedics Today Europe. “A thorough preoperative analysis of all underlying risk factors therefore is necessary before performing realignment surgery for patellofemoral instability. Identifying the potential causes of failure can help to treat, and possibly prevent, future complications,” he said. – by Casey Tingle

Reference:
Nelitz M. Paper #453. Presented at: American Academy of Orthopaedic Surgeons Annual Meeting; March 11-15, 2014; New Orleans.
For more information:
Manfred Nelitz, MD, can be reached at Orthopaedic Specialty Clinic, Clinics Kempten-Oberallgäu, MVZ Oberstdorf, Trettachstrasse 16, 87561, Oberstdorf, Germany; email: manfred.nelitz@kliniken-oa-de.

Disclosure: Nelitz has no relevant financial disclosures.