Achilles tendon elastic properties remain decreased in long term after rupture.

PURPOSE: Rupture of the Achilles tendon results in inferior scar tissue formation. Elastography allows a feasible in vivo investigation of biomechanical properties of the Achilles tendon. The purpose of this study is to investigate the biomechanical properties of healed Achilles tendons in the long term. MATERIALS AND METHODS: Patients who suffered from Achilles tendon rupture were recruited for an elastographic evaluation. Unilateral Achilles tendon ruptures were included and scanned in the mid-substance and calcaneal insertion at least 2 years after rupture using shear wave elastography. Results were compared to patients' contralateral non-injured Achilles tendons and additionally to a healthy population. Descriptive statistics, reliability analysis, and correlation analysis with clinical scores were performed. RESULTS: Forty-one patients were included in the study with a mean follow-up-time of 74 ± 30; [26-138] months after rupture. Significant differences were identified in shear wave elastography in the mid-substance of healed tendons (shear wave velocity 1.2 ±1.5 m/s) compared to both control groups [2.5 ±1.5 m/s (p < 0.01) and 2.8 ±1.6 m/s (p < 0.0001) contralateral and healthy population, respectively]. There was no correlation between the measurements and the clinical outcome. CONCLUSIONS: This study shows that the healed Achilles tendon after rupture has inferior elastic properties even after a long-term healing phase. Differences in elastic properties after rupture mainly originate from the mid-substance of the Achilles tendon, in which most of the ruptures occur. Elastographic results do not correspond with subjective perception. Clinically, sonoelastographical measurements of biomechanical properties can be useful to provide objective insights in tendon recovery.

Rehabilitation of Achilles tendon ruptures: is early functional rehabilitation daily routine?

INTRODUCTION: Ruptures of the Achilles tendon are the most common tendon injuries of the lower extremities. Besides the initial operative or non-operative treatment, rehabilitation of patients plays a crucial role for tendon healing and long-term outcome. As only limited evidence is available for optimized rehabilitation regimen and guidelines for the initial (e.g., first 6 weeks) rehabilitation are limited, this study investigated the current rehabilitation concepts after Achilles tendon rupture. MATERIALS AND METHODS: We analyzed 213 written rehabilitation protocols that are provided by orthopedic and trauma surgery institutions throughout Germany in terms of recommendations for weight-bearing, range of motion (ROM), physiotherapy, and choice of orthosis. All protocols for operatively and non-operatively treated Achilles tendon ruptures were included. Descriptive analysis was carried out and statistical analysis applied where appropriate. RESULTS: Of 213 institutions, 204 offered rehabilitation protocols for Achilles tendon rupture and, therefore, 243 protocols for operative and non-operative treatment could be analyzed. While the majority of protocols allowed increased weight-bearing over time, significant differences were found for durations of fixed plantar flexion between operative (o) and non-operative (n) treatments [fixed 30° (or 20)° to 15° (or 10)°: 3.6 weeks (±0.1; o) vs 4.7 weeks (±0.3; n) (p ≤ 0.0001) and fixed 15° (or 10)° to 0°: 5.8 weeks (±0.1; o) vs 6.6 weeks (±0.2; n) (p ≤ 0.001)]. The mean time of the recommended start of physiotherapy is at 2.9 weeks (±0.2; o) vs 3.3 weeks (±0.4; n), respectively. CONCLUSION: Our study shows that a huge variability in rehabilitation after Achilles tendon rupture exists. This study shows different strategies in rehabilitation of Achilles tendon ruptures using a convertible vacuum brace system. To improve patient care, further clinical as well as biomechanical studies need to be conducted. This study might serve as basis for prospective randomized controlled trials to optimize rehabilitation for Achilles tendon ruptures.

Comparison of tenocytes and mesenchymal stem cells seeded on biodegradable scaffolds in a full-size tendon defect model.

In order to investigate cell-based tendon regeneration, a tendon rupture was simulated by utilizing a critical full-size model in female rat achilles tendons. For bridging the defect, polyglycol acid (PGA) and collagen type I scaffolds were used and fixed with a frame suture to ensure postoperatively a functional continuity. Scaffolds were seeded with mesenchymal stem cells (MSC) or tenocytes derived from male animals, while control groups were left without cells. After a healing period of 16 weeks, biomechanical, PCR, histologic, and electron microscopic analyses of the regenerates were performed. Genomic PCR for male-specific gene was used to detect transplanted cells in the regenerates. After 16 weeks, central ossification and tendon-like tissue in the superficial tendon layers were observed in all study groups. Biomechanical test showed that samples loaded with tenocytes had significantly better failure strength/cross-section ratio (P < 0.01) compared to MSC and the control groups whereas maximum failure strength was similar in all groups. Thus, we concluded that the application of tenocytes improves the outcome in this model concerning the grade of ossification and the mechanical properties in comparison to the use of MSC or just scaffold materials.