In vivo tibiofemoral skeletal kinematics and cartilage contact arthrokinematics during decline walking after isolated meniscectomy

Abstract

We investigated the effects of isolated meniscectomy on tibiofemoral skeletal kinematics and cartilage contact arthrokinematics in vivo. We recruited nine patients who had undergone isolated medial or lateral meniscectomy, and used a dynamic stereo-radiography (DSX) system to image the patients' knee motion during decline walking. A volumetric model-based tracking process determined 3D tibiofemoral kinematics from the recorded DSX images. Cartilage contact arthrokinematics was derived from the intersection between tibial and femoral cartilage models co-registered to the bones. The kinematics and arthrokinematics were analyzed for early stance and loading response phase (30% of a gait cycle), comparing the affected and intact knees. Results showed that four patients with medial meniscectomy had significantly greater contact centroid excursions in the meniscectomized medial compartments while five patients with lateral meniscectomy had significantly greater cartilage contact area and lateral shift of contact centroid path in the meniscectomized lateral compartments, comparing to those of the same compartments in the contralateral intact knees. No consistent difference however was identified in the skeletal kinematics. The current study demonstrated that cartilage-based intra-articular arthrokinematics is more sensitive and insightful than the skeletal kinematics in assessing the meniscectomy effects.

Keywords: Cartilage contact; Dynamic stereo-radiography; In vivo; Meniscectomy; Tibiofemoral kinematics.

Figure 1.

A subject performs decline walking (15 degrees, 1 m/s) while her knee joints were being imaged by a dynamic stereo-radiographic system.

Figure 2.

Determination of cartilage contact arthrokinematics from MRI-acquired tibial and femoral cartilage models co-registered with the CT-acquired bone models, driven by DSX-measured skeletal kinematics.

Figure 3.

The representative cartilage intersection projected on the tibial plateau plane (tibial cartilage outlines—thin-line boundaries; lateral: blue; medial: pink). The intersection depth is color-mapped (the depth increases from blue to red); the black solid dots indicate the depth-weighted contact centroids.

Figure 4.

The 6-DOF tibiofemoral kinematics for (a) four patients with medial meniscectomy and (b) five patients with lateral meniscectomy.

Figure 5.

The average centroid paths of four medial meniscectomy patients on a representative tibial plateau. ** and * denote significant (p<0.5) and marginally significant difference (p<0.1) on ML and AP excursion on the medial compartments between medially meniscectomized and intact knees, respectively.

Figure 6.

The average centroid paths of five lateral meniscectomy patients on a representative tibial plateau. ** denotes the centroid path in the lateral compartment on the meniscectomized knees was significantly shifted laterally, comparing to that of the corresponding compartment on the intact knees (p<0.5).