Osteochondral flake refixation using the parachute technique yields favourable clinical and radiological outcomes following acute patellar dislocation: A case series at short- to mid-term follow-up

Abstract

Purpose

To evaluate short- to mid-term clinical and radiological outcomes following osteochondral flake refixation with transpatellar, absorbable sutures (parachute technique) combined with concomitant medial patellofemoral ligament (MPFL) reconstruction after acute patellar dislocation. It was hypothesized that the parachute technique would yield favourable clinical and functional outcomes and demonstrate good osteochondral integration on radiographic follow-up.

Methods

A retrospective case series was conducted, including patients who underwent osteochondral flake refixation using the parachute technique following acute patellar dislocation between January 2012 and November 2023 at a minimum follow-up of 24 months. Clinical outcomes were assessed using the Visual Analogue Scale (VAS), Tegner Activity Scale (TAS), Kujala Score, International Knee Documentation Committee (IKDC) subjective score and Knee Injury and Osteoarthritis Outcome Score (KOOS). Radiological outcomes were evaluated using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) 2.0 knee score on 3.0-T magnetic resonance imaging (MRI) by three independent raters and intraclass correlation coefficient (ICC) was assessed.

Results

Of 26 identified patients, 20 (77%) were available at final follow-up (mean age 20.8 ± 5.3 years; mean follow-up 62.2 ± 20.5 months; mean defect size 2.8 ± 1.5 cm²). Clinical outcome scores resulted in a mean VAS of 0.5 ± 1.6, TAS of 6 (interquartile range 4–7), Kujala Score of 89.4 ± 12.5, IKDC of 86.7 ± 14.3 and total KOOS of 87.8 ± 14.1. Of all patients, 95% were satisfied with the overall result, and 90% would be willing to undergo the procedure again if necessary. Two patients (10%) required revision surgery (one patella re-dislocation, one failed osteochondral integration). The mean MOCART 2.0 score was 84 ± 8 (range: 75–95), indicating good to excellent osteochondral integration. Inter-rater reliability across the three raters was almost perfect (ICC = 0.84; 95% confidence interval 0.79–0.96).

Conclusion

The parachute technique yields favourable clinical and functional outcomes at short- to mid-term follow-up and demonstrates good to excellent osteochondral integration on MRI following acute patellar dislocation. The technique represents a reliable, simple and single-stage option for the treatment of retropatellar osteochondral flake fractures.

Level of Evidence

Level IV, case series.