Spiked metallic washer and screw for reattachment of the Achilles tendon after repair of a distal rupture

Repair of Achilles tendon rupture using autologous semitendinosus graft in a kidney transplant recipient

Insertional Achilles tendon injuries can be difficult to treat when minimal tendon tissue remains for anastomosis. Moreover, in the chronic case with tendon shortening, operative repair can be more difficult than acute rupture. It is particularly desirable to reinforce the tendons, in addition to performing primary repair, in patients with renal or systemic diseases because of the accelerated collagen degeneration. Many techniques have been described for the surgical management of Achilles tendon rupture; however, none has shown clear superiority. We report the case of a 50-year-old renal transplant patient with a spontaneous distal Achilles tendon injury that we repaired using the pull-out technique reinforced with an autologous semitendinosus graft. At 2 years postoperatively, the ankle-hindfoot scale score was 92 points, and the postoperative course was without complication. We believe that the free hamstring tendon autograft is advantageous for this repair, because it is easy to handle, has limited donor site morbidity, and preserves the structures around the ankle.

Direct tendon attachment and healing to porous tantalum: an experimental animal study

BACKGROUND

The ability to directly attach soft-tissue to metal would have broad clinical application. Previous attempts to obtain normal tendon-to-bone attachment strength have been unsuccessful. In the present study, we hypothesized that when the initial interface mechanical environment is carefully controlled, a highly porous form of tantalum metal would allow the ingrowth of tendon tissue with clinically relevant tendon-to-implant fixation strength approaching that of an intact tendon-to-bone insertion.

METHODS

Supraspinatus tendons from forty skeletally mature dogs were reattached to the greater tuberosity between two custom-designed porous tantalum washers. Clinical function as judged on the basis of gait analysis, reattachment fixation strength and stiffness, and tendon function as seen through muscle volume were evaluated preoperatively, immediately postoperatively, and at three, six, and twelve weeks after surgery. Qualitative and quantitative histomorphologic evaluation was performed at three, six, and twelve weeks after surgery.

RESULTS

Gait analysis with use of force-plate measurements demonstrated return to a normal gait pattern by three weeks after surgery. Tendon-implant strength as a percentage of normal, contralateral controls increased significantly, from 39% at the time of surgery to 67% at three weeks, 99% at six weeks, and 140% at twelve weeks (p < 0.0014). The stiffness of the construct also increased and approached that of normal tendon, measuring 47% at the time of surgery, 62% at three weeks, 94% at six weeks, and 130% at twelve weeks (p < 0.0299). Supraspinatus muscle volume initially decreased by 33% but recovered to 92% of normal by twelve weeks (p < 0.01). Histomorphologic evaluation showed Sharpey-like fibers inserting onto the surface of the porous tantalum. Quantitative histomorphometric analysis revealed a time-dependent increase in the density of the collagen tissue filling the metal voids below the implant surface of first the bottom washer and then the top washer.

CONCLUSIONS

Robust biologic ingrowth of tendon into a porous tantalum implant surface can be achieved under conditions of secure initial mechanical fixation. The strength and stiffness of the tendon-implant construct reached normal levels by six to twelve weeks in this animal model.

Achilles rupture in the athlete. Current science and treatment

Achilles tendon ruptures became increasingly common in the latter half of the 20th century. Once the diagnosis is made, the patient's goals and objectives should be clearly stated. The treatment choice should incorporate the patient's needs, desires, objectives, and functional goals to assure an optimal result.

A comparison of soft-tissue anchors in tendo achilles reattachment

This prospective study evaluated four soft-tissue fixation modalities, used in seven different combinations, to reattach the tendo Achilles in 34 cadaveric specimens. Ultimate loads, elastic moduli, and modes of failure were evaluated by loading the specimen in a cantilevered fashion on an Instron. Mann-Whitney U tests were performed to compare the failure load data for statistical significance. Although the use of two Mitek SuperAnchors showed better load resistance than one anchor (p < .01), there was no significant improvement between using two or three anchors (one anchor 116 +/- 24 N, two anchors 234 +/- 21 N, three anchors 277 +/- 80 N). Two Bionx Bankart Tacks demonstrated no significant difference over using a single tack (one tack 178 +/- 57 N, two tacks 214 +/- 86 N). No statistical difference was observed between the screw and washer systems (screw with polyacetal resin washer 307 +/- 80 N, screw with metal washer 290 +/- 81 N). Both screw and washer systems did show greater stability when compared with a single Mitek SuperAnchor (p < .01) or a single Bionx Bankart Tack (p < .05). Similar analyses using the Mann-Whitney U tests were performed on the elastic modulus data. Analysis of the displacement data among all groups showed no statistical difference. Observations of the mode of failure exhibited 86% of Mitek SuperAnchor failed secondary to suture, and 70% of the Bionx Bankart Tack and 90% of the screw and washer systems failed because of the tendon shearing around the fixation. The comparisons of cost-effectiveness among the fixations showed the Synthes screw and polyacetal resin spiked washer to have the lowest cost to load ratio ($0.15/N).