Arthroscopy-controlled medial reefing and lateral release for recurrent patellar dislocation: clinical, radiologic outcomes and complications

Abstract

Background: Few studies have reported the clinical outcomes of the medial reefing procedure and lateral release with arthroscopic control of medial retinacular tension in patients with recurrent patellar dislocation. The purpose of this study was to investigate the clinical, radiologic outcomes and complications of arthroscopy-controlled medial reefing and lateral release.

Methods: Patients who underwent arthroscopy-controlled medial reefing and lateral release for recurrent patellar dislocation between November 2007 and June 2017 were retrospectively evaluated. The clinical outcome (Kujala score), radiologic outcome (congruence and patellar tilt angles), and complications were evaluated at final follow-up. The results were also compared with literature-reported outcomes of other surgical procedures for patellar dislocation.

Results: Twenty-five patients (mean age, 18.3 ± 4.8 years) were included in the study. The mean clinical follow-up period was 7.0 ± 2.5 (range, 3.8-12.2) years. The mean Kujala score was significantly improved from 54.7 ± 14.0 (range, 37-86) preoperatively to 91.0 ± 7.6 (range, 63-99) at a mean follow-up period of 7 years (P < 0.001). The radiologic results also significantly improved from 17.8° ± 5.9° to 6.8° ± 2.4° (P < 0.001) in the congruence angle and from 17.5° ± 8.2° to 5.6° ± 3.1° (P < 0.001) in the patella tilt angle at a mean follow-up period of 3.6 years. One patient developed a redislocation after a traumatic event, and two patients showed patellofemoral osteoarthritis progression.

Conclusions: Arthroscopy-controlled medial reefing and lateral release significantly improved the clinical and radiologic outcomes of the patients with recurrent patellar dislocation at a mean follow-up period of 7 years. The results of this study are comparable with the literature-reported outcomes of other surgical procedures for patellar dislocation.

Level of evidence: Level IV, retrospective therapeutic case series.

Keywords: Arthroscopy‐controlled medial reefing; Complication; Congruence angle; Kujala score; Patellar dislocation; Patellar tilt angle.

Fig. 1

Arthroscopic findings from the superolateral portal of the left knee showing preoperative (a) and postoperative (b) statuses of patellar subluxation. a Patellar lateral subluxation and patellofemoral malalignment. b Lateral patellar edge positioned in line with the lateral trochlear border after arthroscopy-controlled medial reefing and lateral release. P, patella; F, femur

Fig. 2

Surgical procedures of the percutaneous lateral release and medial reefing for recurrent patellar dislocation of the left knee. a Percutaneous lateral release using Metzembaum scissors. b The vastus medialis oblique muscle and medial retinacular complex advanced over the quadriceps tendon and border of the patella, with 5–10 mm of overlap depending on the arthroscopic finding of patellar reduction. VMO, vastus medialis oblique muscle

Fig. 3

Arthroscopy-controlled evaluation of medial retinacular tension of the left knee from the superolateral (SL) portal before the mattress sutures were tied

Fig. 4

Measurement of the congruence and patellar tilt angles on the left knee skyline view (inferior-superior projection of the patella in 45° flexion). a Congruence angle measurement. The highest point of the medial (M) and lateral (L) condyles, and the lowest point of the intercondylar sulcus (S) were identified. The zero-reference line (SO, dotted line) bisecting the sulcus angle (MSL) was established. The lowest point on the articular ridge of the patella (A) was identified, and a line from S to A was drawn. The congruence angle was measured as the angle ASO (α). All values medial and lateral to the zero-reference line SO are designated as negative and positive, respectively. b The patellar tilt angle (β) was measured as the angle between a line intersecting the widest bony structure of the patella and a line tangential to the anterior surface of the femoral condyles on a skyline view

Fig. 5

Flowchart of the enrolled patients in this study