Background

Menisci are an essential structure for the load distribution of the knee joint. Meniscectomy causes elevated tibiofemoral contact pressure, leads to degenerative changes of the articular cartilage. Surgical repair techniques can restore contact characteristics. Traditional inside-out repair may increase the risk of injury to posterior structure. An alternative technique to repair meniscus is suture with circumferential stitch technique proposed. There is a paucity of literature comparing contact characteristics of all-inside suture loop technique and circumferential stitch technique for meniscus repair.

Purpose

To analyze the contact characteristics of an all-inside suture loop technique and circumferential stitch technique in porcine knee joints.
Study Design: Controlled laboratory study

Methods

Sixteen porcine knees each underwent two different testing conditions: intact meniscus and bucket handle tear of the meniscus. Then, all specimens were randomized to repair with suture loop technique or circumferential stitch technique. Testing was performed at 30 degrees flexion, under a 325-N axial load. Pressure sensors were placed between femoral condyle and meniscus. Contact characteristic variables (contact area, mean contact pressure, and peak contact pressure) were measured by the Tekscan sensor in the medial and lateral compartment.

Results

Bucket handle tear of medial meniscus had a significantly higher load transmission and contact pressure in the medial compartment of the knee joint than intact state (247 ± 48 N versus 205 ± 41 N, and 1.1 ± 0.2 MPa versus 0.9 ± 0.2 MPa, respectively; P < 0.05). There was no significant difference in the contact area between each simulated condition. Both suture repair techniques could restore load transmission and contact pressure to be comparable to the intact state. However, circumferential stitch repair had the peak contact pressure significantly higher than in the intact state (P < 0.05) and similar to the tear condition (P = 1).

Conclusion

Bucket handle tear of medial meniscus significantly increased load transmission, contact pressure, and peak pressure in the joint’s medial compartment than in the intact state. Both suture loop repair and circumferential stitch repair could restore load transmission and contact pressure of medial meniscus comparable to the intact state. Circumferential stitch repair had the peak contact pressure higher than in the intact state.
Clinical Relevance: Locked bucket handle tear of medial meniscus alters load transmission in the medial compartment and could develop osteoarthritis. Understanding the restoration of contact characteristics by both suture repair techniques will help surgeon to determine the best strategy for treating medial meniscus tears. Furthermore, repairing with minimal suture expose in the knee joint is preferable to avoid unwanted increasing peak contact pressure in the knee joint.
Keywords: medial meniscus; contact pressure; circumferential stitch; suture loop