Stepwise Lengthening of the Quadriceps Extensor Mechanism for Severe Obligatory and Fixed Patella Dislocators

Patellofemoral Instability in the Pediatric and Adolescent Population: From Causes to Treatments

BACKGROUND

Patella instability is one of the most common knee injuries in the adolescent patient. There are several pathoanatomic risk factors which should be assessed via several modalities, including X-rays, magnetic resonance imaging (MRI), or even CT scan.

OBJECTIVES

We intend to review these risk factors along with the nonsurgical and surgical techniques used to prevent recurrent dislocations.

METHODS

We completed an extensive review of the recent literature concerning pediatric and adolescent patellar dislocation and subsequent treatment modalities.

RESULTS

We review in detail the risk factors such as patella alta, trochlear dysplasia, lateralization of the tibial tubercle or medialization of the trochlear groove (increased tibial tubercle to trochlear groove (TT-TG) distance), lower limb malalignment, excessive femoral anteversion and/or tibial torsion, and hyperlaxity. There are classification systems for dislocators, and a natural progression of instability that patients often proceed through. Only after a patient has continued to dislocate after bracing and physical therapy is surgical treatment considered. Surgical techniques vary, with the workhorse being the medial patellofemoral ligament (MPFL) reconstruction. However, there are a variety of other techniques which add onto this procedure to address other anatomic risk factors. These include the tibial tubercle osteotomy to address a large TT-TG distance or trochleoplasty to address the lack of a trochlear groove.

CONCLUSIONS

Nonsurgical and surgical treatments for patella dislocators are tailored to the pathoanatomic risk factors in each patient.

Stepwise lengthening of quadriceps extensor mechanism for severe obligatory and fixed patella dislocators: Four-year clinical and surgical outcomes

OBJECTIVES

The purpose of this study was to report clinical and surgical outcomes of medial patellofemoral ligament reconstruction (MPFLR) and concomitant quadriceps lengthening to treat fixed and obligatory patellofemoral instability (PFI) in the pediatric population.

METHODS

Patients with obligatory or fixed PFI who underwent simultaneous MPFLR and quadriceps lengthening from 2008 to 2020 were reviewed. Of the 413 records, 24 fit the inclusion criteria. Demographic information, surgical details, associated diagnoses, and outcome measures were collected for each knee. Complications and additional surgeries were also obtained.

RESULTS

The final cohort included 20 patients (10 male, 10 female), with a total of 24 knees. The average age at the time of surgery was 11.9 ​± ​3.1 (5.4-17.3). Seventeen were obligatory dislocators in flexion and 7 were fixed dislocators. Average follow-up was 4.3 ​± ​2.4 (1.3-9.4) years. One patient was lost to follow-up and excluded from the study. The mean outcome measures were as followed; KOOS 82, HSS Pedi-FABS 9, IKDC 76, Kujala 78, BPII 67, and SANE 90. Six patients had subsequent instability episodes. Ten patients had a subsequent surgery.

CONCLUSIONS

Reports on quadriceps lengthening to treat PFI in the pediatric population are rare. Six (25 ​%) of the 24 knees included had subsequent PFI. Although this is a high rate of recurrent instability, no second surgeries were indicated for infection, extensor mechanism weakness, or contracture. The authors conclude that simultaneous MPFLR and stepwise quadriceps lengthening can be used to effectively manage fixed and obligatory PFI in this difficult patient population.

LEVEL OF EVIDENCE

IV.

Medial Patellofemoral Ligament Reconstruction with Open Physes

Through this article, the authors aim to summarize the techniques performed on both first time and recurrent skeletally immature patients experiencing patellar dislocation. This article focuses on several key points, such as the importance of medial patellofemoral ligament femoral insertions being distal to the growth plate and performing extensive lateral release and quadricep tendon lengthening in cases of obligatory dislocation. Although acknowledging the procedures discussed cannot be considered for all patients, as individuals with open growth plates may require additional operative time, in many cases these techniques yield high rates of success.