Non-suppurative Tissue Reaction to Polyether Ether Ketone Anchor in Rotator Cuff Repair

Abstract

Introduction: Interferential screws and anchors have played a major role in fixation of soft tissue to bony tunnel. With advent of time, there developed metal anchors, biodegradable anchors, bioinert anchors, etc. Biodegradable anchors had complications such as reactive synovitis, cyst formation, soft-tissue inflammation, and local osteolysis. Polyether ether ketone (PEEK) which was biologically inert and radiolucent was introduced to overcome the disadvantages of anchors. We present a case of non-suppurative tissue reaction to PEEK anchor following rotator cuff repair.

Case report: A 58-year-old male patient presented to us with signs of rotator cuff tear following injury to his shoulder. Magnetic resonance imaging depicted a massive cuff tear with retraction of cuff. Considering the degree of cuff tear, cuff was repaired with mini open method using two metallic suture anchor and two PEEK knotless bioraptor foot print suture anchor. Surgical wound healing was uneventful and suture was removed on 14th day following surgery. Three weeks following surgery, the patient had pain and rise in temperature over shoulder with raised erythrocyte sedimentation rate and C-reactive protein which subsided in 7 days with empirical antibiotics. Later, at 3 months, the patient had serous discharge from surgical site, on which exploration revealed pale yellow material vicinity to PEEK anchor. Other than pus cells in smear, discharge was negative to routine culture, grams stain, and cartridge-based nucleic acid amplification test for tuberculosis. Surprisingly, surrounding muscles were healthy, red in color, and contracting to stimulation. Following removal of both the PEEK anchors, local symptoms subsided with improvement in patients shoulder function.

Conclusion: There were cases of tissue reaction to PEEK material in the literature such as osteolysis and cyst formation. In addition, non-suppurative inflammation can occur in response to PEEK material. Awareness about the non-suppurative inflammation property of PEEK material may help future surgeons to manage the condition better than us.

Keywords: Polyether ether ketone; anchor; inflammation; non-suppurative.

Figure 1

Magnetic resonance imaging of shoulder, full-thickness tear of supraspinatus (white arrow).

Figure 2

Post-operative X-ray (White arrow: PEEK foot print anchor).

Figure 3

Skin inflammation after 106 days of index surgery.

Figure 4

(a) Intraoperative picture showing necrotic material on the PEEK screw (white arrow), (b) PEEK screw after removal.

Figure 5

Healed skin after PEEK screw removal.

Figure 6

Satisfactory shoulder function at 2 years follow-up.