4-in-1 Quadricepsplasty for Fixed and Habitual Dislocation of Patella

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.

4-in-1 Quadricepsplasty for Habitual and Fixed Lateral Patellar Dislocation in Children

BACKGROUND

Habitual and fixed patellar dislocations represent extreme forms of patellar instability and can lead to significant functional loss. The underlying complex pathoanatomy of a laterally positioned and shortened extensor mechanism poses challenges in its management. The purpose of our study was to evaluate the anatomic risk factors and outcomes of a 4-in-1 quadricepsplasty (wide lateral releases, Insall proximal tube realignment, Roux-Goldthwait patellar tendon hemi-transfer, and step-wise quadriceps lengthening) for stabilization of habitual and fixed patellar dislocation.

METHODS

In a retrospective study, all patients with habitual and fixed patellar dislocation who underwent 4-in-1 quadricepsplasty and had a minimum 2-year follow-up were identified. Preoperative magnetic resonance imagings were evaluated for the presence of anatomic risk factors. As a prospective part of the study, patient-reported outcomes were collected using validated instruments including Pedi-IKDC, HSS-Pedi FABS activity score, BPII 2.0 score, Kujala score, and KOOS score.

RESULTS

Seventeen knees (12 patients) formed the study cohort. Twelve knees had habitual dislocation (9 in extension and 4 in flexion) and 5 had fixed dislocation. Mean age was 9 years. 6/17 (35.3%) knees were associated with syndromes. On magnetic resonance imaging, trochlear dysplasia was the most common anatomic risk factor present in 15/17 (88.2%) knees. 13/17 (76%) knees had presence of 2 or more risk factors. At the mean follow-up of 43.3 months, the mean Pedi-IKDC score was 88.1, the HSS-Pedi FABS activity score was 15.6, the BPII 2.0 score was 78.2, the Kujala score was 90, KOOS score was 93.9, and overall patient satisfaction score was 83.3. For complications, 3/17 knees (17.6%) had recurrent patellar instability, 1 knee had postoperative stiffness that required manipulation under anesthesia and 1 knee had a superficial wound infection.

CONCLUSIONS

Most patients with habitual and fixed patellar dislocation present during the first decade of life. There are several underlying anatomic risk factors, the most common being trochlear dysplasia and patellar tilt. The 4-in-1 quadricepsplasty technique provides reliable patellar stabilization, satisfactory clinical results, and acceptable patient-reported outcomes at a minimum 2-year follow-up, with a 17.6% redislocation rate.

LEVEL OF EVIDENCE

Level IV.

A 20-Year Retrospective Study of Children and Adolescents Treated by the Three-in-One Procedure for Patellar Realignment

BACKGROUND

Patellar instability is the most common disorder of the knee during childhood and adolescence. Surgical treatment significantly reduces the rate of redislocation, but the underlying pathologies and pattern of instability may affect the results. We aimed to report the clinical and functional outcomes of the three-in-one procedure for patellar realignment in a cohort of skeletally immature patients with or without syndromes and various patterns of chronic patellar instability.

METHODS

We retrospectively investigated 126 skeletally immature patients (168 knees) affected by idiopathic or syndromic patellar instability, who underwent patella realignment through a three-in-one procedure. We classified the instability according to the score proposed by Parikh and Lykissas.

RESULTS

Patellar dislocation was idiopathic in 71 patients (94 knees; 56.0%) and syndromic in 55 (74 knees; 44.0%). The mean age at surgery was 11.5 years (range 4-18) and was significantly lower in syndromic patients. Syndromic patients also exhibited more severe clinical pattern at presentation, based on the Parikh and Lykissas score. The mean follow-up was 5.3 years (range 1.0-15.4). Redislocation occurred in 19 cases, with 10 cases requiring further realignment. The Parikh and Lykissas score and the presence of congenital ligamentous laxity were independent predictors of failure. A total of 22 knees in 18 patients required additional surgical procedures. The post-operative Kujala score was significantly lower in patients with syndromic patellar instability.

CONCLUSIONS

The type of instability and the presence of underlying syndromes negatively affect the rate of redislocation and the clinical and functional outcome following patellar realignment through the three-in-one procedure. We recommend the consideration of alternative surgical strategies, especially in children with severe syndromic patellar dislocation.