P² porous titanium implants improve tendon healing in an acute rat supraspinatus repair model.

Abstract

Current techniques in rotator cuff repair often lack structural integrity. P² porous titanium-coated constructs (DJO Surgical, Austin, TX, USA) promote osseointegration and soft tissue ingrowth. This study examined the ability of this material to improve the structural integrity of supraspinatus tendon repair in a rat model. We hypothesized that P² implants placed at the tendon-to-bone interface would improve mechanical and histologic measures of supraspinatus healing. Forty rats underwent supraspinatus repairs with P² implants in 1 shoulder and standard repair in the other. Rats were humanely killed at time 0 (n = 3), 2 weeks (n = 8), 4 weeks (n = 15), and 12 weeks (n = 14). Tendon-to-bone composite specimens were harvested and evaluated mechanically and histologically. Tendon cross-sectional area was decreased in the P² implant group at 4 weeks, percentage of relaxation was increased at 2 weeks, elastic modulus was increased at 4 weeks, and maximum load and maximum stress were both increased at 2 and 4 weeks. Histologic analysis revealed no foreign body reactions within or around the P² implant, and healthy viable bone was visible within the P² implant. The results support our hypothesis, specifically in early healing, in this randomized controlled animal study. These data support the use of P² porous titanium implants to improve tendon-to-bone healing.