Patellar Base Support Technique During Manipulation Under Anesthesia for Knee Arthrofibrosis Limits the Risk of Iatrogenic Complications

Abstract

Knee extension contracture is a common postinjury and postsurgical complication, which decreases knee joint flexion. Many techniques have been described in the literature to restore knee flexion, with the most common one being an arthroscopic lysis of adhesions. However, in severe cases, additional intra- and extra-articular procedures are needed to restore full knee flexion. Manipulation under anesthesia (MUA) is one of them. Unfortunately, it may lead to devastating complications, such as iatrogenic rupture of the patellar tendon or fractures of the patella or tibial tuberosity. Therefore, the purpose of this report is to present a safer modification of MUA for knee extension contracture in cases in which excessive force is demanded to achieve flexion. The key aim of the "patellar base support" technique (PBS technique) is to stretch the contracted quadriceps muscle with controlled and decreased tension on the patella, patellar tendon, and tibial tuberosity.

Fig 1

Preparation for “patellar base support” (PBS) technique without arthroscopic assistance. The right knee is shown with the patient supine. (A) Creation of superolateral approach. (B) Introduction of the switching stick into the suprapatellar recess. (C) Creation of superomedial approach. (D) Switching stick is pulled out over the skin.

Fig 2

Preparation for patellar base support PBS technique with arthroscopic assistance. The left knee is shown with the patient supine. White asterisk denotes the switching stick. AM, anteromedial; SL, superolateral.

Fig 3

Introduction and stabilization of the switching stick on the patellar base. The left knee is shown with the patient supine. (A) Introduction of the switching stick into the suprapatellar recess. (B) Stabilization of the switching-stick on the patellar base. White asterisks denote to the switching stick; black asterisks denote the patella; white arrow denotes the distal part of quadriceps tendon merged with suprapatellar fat pad.

Fig 4

Switching stick pulled out over the skin after arthroscopic preparation to the PBS technique. The left knee is shown with the patient supine. White asterisk denotes the switching stick. AM, anteromedial; SL, superolateral; SM, superomedial.

Fig 5

Patellar base support technique with marked force vectors, side view. The left knee is shown with patient supine. Yellow arrow denotes the assistant pushes the stick distally and anteriorly with simultaneous stabilization of the switching stick on patellar base; green arrow denotes the main surgeon controls the tension of the patellar tendon with his/her thumb; and white arrow denotes using the other hand the main surgeon bends the knee into maximal flexion.

Fig 6

Patellar base support technique with marked force vectors, superior view. The left knee is shown with patient supine. Yellow arrows shows the assistant pulling the stick distally and anteriorly; purple arrows show the assistant simultaneously stabilizing the switching stick on the patellar base; the green arrow shows the main surgeon controlling the tension of the patellar tendon with his/her thumb.

Fig 7

Severe patellofemoral cartilage damage in a relatively short time in a patient with knee extension contracture, due to overload during rehabilitation by means of painful, excessively forceful flexion. The left knee, sagittal (A1 and B1) and axial (A2 and B2) MRI scans. The patient, who has a knee extension contracture, was rehabilitated by means of painful, excessively forceful flexion. While the improvement in knee flexion was minimal, the patellofemoral cartilage (arrows) was severely damaged in a relatively short time (February 2019 to January 2021) as a result of these manipulations.

Fig 8

Proposed workflow for knee extension contracture treatment. LOA, lysis of adhesions; MUA, manipulation under anesthesia; PBS, patellar base support.