Biomechanical and histologic comparison of Achilles tendon ruptures reinforced with intratendinous and peritendinous plantaris tendon grafts in rabbits: an experimental study

Biomechanical comparison of new Achilles tendon rupture repair technique the "Giftbox" versus the Krackow technique in New Zealand white rabbits: An experimental animal study

INTRODUCTION

To compare the strength between the Achilles tendons repaired with the "Giftbox" and the Krackow techniques in New Zealand white rabbits post six weeks of tendon healing.

MATERIALS AND METHODS

Eight rabbits were randomized into Giftbox and Krackow groups. Tenotomy was performed on the Achilles tendon of one side of the lower limb and repaired with the respective techniques. The contralateral limb served as control. Subjects were euthanized six weeks post-operative, and both repaired and control Achilles tendons were harvested for biomechanical tensile test.

RESULTS

The means of maximum load to rupture and tenacity in the Giftbox group (156.89 ± 38.49 N and 159.98 ± 39.25 gf/tex) were significantly different than Krackow's (103.55 ± 27.48 N and 104.91 ± 26.96 gf/tex, both p = 0.043).

CONCLUSION

The tendons repaired with Giftbox technique were biomechanically stronger than those repaired with Krackow technique after six weeks of tendon healing.

Repair of acute Achilles tears with plantaris augmentation

PURPOSE

To determine the benefits associated with using the fanned out plantaris tendon as a membrane to cover and augment the acute Achilles tendon midportion end-to-end suture repair.

METHODS

Between 2014 and 2018, 31 (67.4%) patients had plantaris augmented reconstruction and 15 simple end-to-end suture. The clinician filled out the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot scale and the patient the Achilles tendon total rupture score (ATRS). Examination included clinical examination, limb symmetry index (LSI) using the heel rise test, and ultrasound determination of cross-sectional area (CSA).

RESULTS

80.4% were males, mean age 41 (SD 6.7, range 29-57), of which 82.6% were sports accidents. 39/46 were operated in less than two weeks from injury. 82.6% were available at the two year follow-up. Duration of surgery (62.3 min vs 58, p = 0.45), AOFAS (89.6 vs 88.4, p = 0.61 and 97.2 vs 96.8, p = 0.72), ATRS (86.3 vs 83.8, p = 0.33 and 95.6 vs 93.6, p = 0.12), LSI (60.8% vs 58.75, p = 0.24 and 80.5 vs 79, p = 0.29), CSA (3.39cm² vs 3.36, p = 0.82 and 2.57 vs 2.59, p = 0.87), return to sport (80% vs 57, p = 0.15 and 84.6 vs 85.7, p = 1.00), and complications at six months and two years were comparable between the two techniques.

CONCLUSION

Fanned out plantaris augmentation of acute Achilles tendon tears yields excellent and comparable clinical and ultrasonographic results to end-to-end suture at mid-term follow-up.

Quantitative US Elastography Can Be Used to Quantify Mechanical and Histologic Tendon Healing in a Rabbit Model of Achilles Tendon Transection

Purpose To determine the time-dependent change in strain ratios (SRs) at the healing site of an Achilles tendon rupture in a rabbit model of tendon transection and to assess the correlation between SRs and the mechanical and histologic properties of the healing tissue. Materials and Methods Experimental methods were approved by the institutional animal care and use committee. The Achilles tendons of 24 New Zealand white rabbits (48 limbs) were surgically transected. The SRs of Achilles tendons were calculated by using compression-based quantitative ultrasonographic elastography measurements obtained 2, 4, 8, and 12 weeks after transection. After in vivo elastography, the left Achilles tendon was harvested for mechanical testing of ultimate load, ultimate stress, elastic modulus, and linear stiffness, and the right tendons were harvested for tissue histologic analysis with the Bonar scale. Time-dependent changes in SRs, mechanical parameters, and Bonar scale scores were evaluated by using repeated-measures analysis of variance. The correlation between SRs and each measured variable was evaluated by using the Spearman rank correlation coefficient. Results Mean SRs and Bonar scale values decreased as a function of time after transection, whereas mechanical parameters increased (P < .001). SR correlated with ultimate stress (ρ = 0.68, P <.001,) elastic modulus (ρ = 0.74, P <.001), and the Bonar scale (ρ = 0.87, P <.001). Conclusion Quantitative elastography could be a useful method with which to evaluate mechanical and histologic properties of the healing tendon. ^© RSNA, 2017 Online supplemental material is available for this article.

Treating Achilles tendon rupture in rats with bone-marrow-cell transplantation therapy

BACKGROUND

Bone marrow cells possess multipotentiality and have been used for several treatments. We hypothesized that bone marrow cells might differentiate into regenerated tendon and that several cytokines within bone marrow cells might accelerate tendon healing. Therefore, we treated Achilles tendon ruptures in a rat model with transplantation of whole bone marrow cells.

METHODS

Nine F344/Nslc (Fisher) rats were the source of bone marrow cells and mesenchymal stem cells as well as normal Achilles tendons. Eighty-seven Fisher rats were used for the experiments. The rats were divided into three groups: the BMC group (bone marrow cells injected around the tendon), the MSC group (mesenchymal stem cells injected around the tendon), and the non-treated control group (incision only). Outcome measures included mechanical testing, collagen immunohistochemistry, histological analysis, and reverse transcription-polymerase chain reaction to detect expression of transforming growth factor-β (TGF-β) and vascular endothelial growth factor (VEGF).

RESULTS

The ultimate failure load in the BMC group was significantly greater than that in the non-treated or the MSC group at seven days after incision (3.8 N vs. 0.9 N or 2.1 N, p < 0.016) and at fourteen days after incision (10.2 N vs. 6.1 N or 8.2 N, p < 0.016). The ultimate failure load in the BMC group at twenty-eight days after incision (33.8 N) was the same as that of normal tendon (34.8 N). The BMC group demonstrated stronger staining for type-III collagen at seven days after incision and stronger staining for type-I collagen at twenty-eight days than did the MSC group. Expression of TGF-β and VEGF in the BMC group was significantly increased compared with that in the other groups at four days after incision (TGF-β: 1.6 vs. 1.3 or 0.6, p < 0.01; VEGF: 1.7 vs. 1.1 or 0.9, p < 0.01).

CONCLUSIONS

Transplantation of whole bone marrow cells may be a better and more readily available treatment for Achilles tendon rupture than cultured mesenchymal stem cells.