The effect of a dynamic PCL brace on patellofemoral compartment pressures in PCL-and PCL/PLC-deficient knees

Tyler Welch,Melodie Metzger,Ronald Kvitne,Karen Mohr,Thomas Keller,Ruben Maldonado

doi:10.1186/s40634-017-0085-5

Tyler Welch, Melodie Metzger + Show 4 more

Open Access

https://doi.org/10.1186/s40634-017-0085-5

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Abstract

BackgroundThe natural history of posterior cruciate ligament (PCL) deficiency includes the development of arthrosis in the patellofemoral joint (PFJ). The purpose of this biomechanical study was to evaluate the hypothesis that dynamic bracing reduces PFJ pressures in PCL- and combined PCL/posterolateral corner (PLC)-deficient knees. Study Design: Controlled Laboratory Study.MethodsEight fresh frozen cadaveric knees with intact cruciate and collateral ligaments were included. PFJ pressures and force were measured using a pressure mapping system via a lateral arthrotomy at knee flexion angles of 30°, 60°, 90°, and 120° in intact, PCL-deficient, and PCL/PLC-deficient knees under a combined quadriceps/hamstrings load of 400 N/200 N. Testing was then repeated in PCL- and PCL/PLC-deficient knees after application of a dynamic PCL brace.ResultsApplication of a dynamic PCL brace led to a reduction in peak PFJ pressures in PCL-deficient knees. In addition, the brace led to a significant reduction in peak pressures in PCL/PLC-deficient knees at 60°, 90°, and 120° of flexion. Application of the dynamic brace also led to a reduction in total PFJ force across all flexion angles for both PCL- and PCL/PLC-deficient knees.ConclusionDynamic bracing reduces PFJ pressures in PCL- and combined PCL/PLC-deficient knees, particularly at high degrees of knee flexion.

Highlights

The natural history of posterior cruciate ligament (PCL) deficiency includes the development of arthrosis in the patellofemoral joint (PFJ)
Two of the ten specimens received showed evidence of PCL insufficiency based on posterior drawer examination, which was confirmed with gross inspection and were eliminated from the study
When analyzed across all angles, force through the PFJ was significantly reduced in PCL-deficient knees when a dynamic brace was applied to the extremity (p < 0.001) (Fig. 2a)

Summary

Introduction

The natural history of posterior cruciate ligament (PCL) deficiency includes the development of arthrosis in the patellofemoral joint (PFJ). The exact mechanism of articular cartilage degeneration in PCL-deficient knees remains unknown; several cadaveric studies have reported that PCL deficiency leads to a significant increase in contact pressure in these two knee compartments (Gill et al 2003b; Grood et al 1988; Markolf et al 1993; Strobel et al 2003) This increase in compartmental pressure is possibly the result of increased anterior–posterior laxity (MacDonald et al 1996; Anderson et al 2012; Fanelli & Edson 1995; Gill et al 2003b; Goyal et al 2012; Kumagai et al 2002; Logan et al 2004) and rotational instability (Jonsson & Karrholm 1999 Gill et al 2003a; Kennedy et al 2013) of the knee. The PLC and PCL play a symbiotic role in resisting excessive external rotation and posterior translation of the proximal tibia

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