Alterations in structure of the muscle-tendon unit and gait pattern after percutaneous repair of Achilles tendon rupture with the Dresden instrument

Paratenon preserving repair of the midsubstance acute Achilles tendon rupture: a systematic review and meta-analysis with best- and worst-case analyses for rerupture rates

INTRODUCTION

Paratenon preserving techniques to facilitate acute Achilles tendon rupture repair (AATR) functions by maintaining vascularity and biology for optimal healing response. Therefore, the purpose is to evaluate the outcomes following paratenon preserving repair of the midsubstance AATR. The hypothesis was that paratenon-preserving techniques demonstrate high return to play rates and low complication rates for the repair of the midsubstance AATR.

MATERIALS AND METHODS

A systematic review of the PubMed, Embase, and the Cochrane Library databases was performed by two authors using specific search terms and eligibility criteria. The assessment of the evidence was two-fold: level and quality of evidence. A meta-analysis of proportions for the various complication rates was performed using the restricted maximum likelihood method following the Freeman-Tukey double-arcsine transformation. Fixed effects models were employed if I2 < 25% (low heterogeneity), and random effects models were employed if I2 ≥ 25% (moderate to high heterogeneity).

RESULTS

The pooled return to play rate was 90.3%. The pooled rerupture rate as reported was 0.9% (best-case scenario 0.8% and worst-case scenario 6.8%). No meaningful subgroup analysis for rerupture rates could be performed based on the meta-regression. The pooled complication rate other than reruptures was 4.8%. The pooled infection rates were 0.3%, DVT rates were 1.6%, and sural nerve injury rates were 0.3%.

CONCLUSIONS

Paratenon preserving techniques that are minimally invasive in nature demonstrated safe and favorable outcomes with high return to play rates and low complication rates for the repair of the midsubstance AATR.

Effects of tendon elongation on plantar pressure and clinical outcomes: A comparative analysis between open repair and minimally invasive surgery

PURPOSE

The aim of this study was to assess whether variances in Achilles tendon elongation are linked to dissimilarities in the plantar pressure distribution following two different surgical approaches for an Achilles tendon rupture (ATR).

METHODS

All patients who were treated with open or minimally invasive surgical repair (MIS) and were over 2 years post their ATR were eligible for inclusion. A total of 65 patients with an average age of 43 ± 11 years were included in the study. Thirty-five patients were treated with open repair, and 30 patients were treated with MIS. Clinical outcomes were evaluated using the American Orthopedic Foot and Ankle Society (AOFAS) and ATR Score (ATRS). Achilles tendon elongation was measured using axial and sagittal magnetic resonance imaging scans. Plantar pressure measurements for the forefoot, midfoot and hindfoot during gait were divided into percentages based on total pressure, measured in g/cm2 for each area.

RESULTS

The average AOFAS score was found 'excellent' (93 ± 2.8) in the MIS group, while it was found 'good' (87.4 ± 5.6) in the open repair group. In addition, the MIS group showed significantly superior ATRS scores (78.8 ± 7.4) compared to the open repair group (56.4 ± 15.4) (p < 0.001). The average tendon elongation in the MIS group was 11.3 ± 2 mm, while it was 17.3 ± 4.3 mm (p < 0.001) in the open repair group. While the open repair group showed significantly higher plantar pressure distribution in the initial contact and preswing phases compared to uninjured extremities, there was no significant difference between the uninjured extremities and the MIS group.

CONCLUSION

In conclusion, the findings of this study demonstrated that minimally invasive surgery was associated with less tendon elongation, more proximity to the plantar pressure distributions of the uninjured extremity and superior clinical outcomes compared to open surgical repair. Therefore, minimally invasive surgery may be considered a more suitable option for acute Achilles tendon repair to achieve overall better outcomes.

LEVEL OF EVIDENCE

Level III.

Postoperative Long-Term Monitoring of Mechanical Characteristics in Reconstructed Soft Tissues Using Biocompatible, Immune-Tolerant, and Wireless Electronic Sutures

Accurate postoperative assessment of varying mechanical properties is crucial for customizing patient-specific treatments and optimizing rehabilitation strategies following Achilles tendon (AT) rupture and reconstruction surgery. This study introduces a wireless, chip-less, and immune-tolerant in vivo strain-sensing suture designed to continuously monitor mechanical stiffness variations in the reconstructed AT throughout the healing process. This innovative sensing suture integrates a standard medical suturing thread with a wireless fiber strain-sensing system, which incorporates a fiber strain sensor and a double-layered inductive coil for wireless readout. The winding design of Au nanoparticle-based fiber electrodes and a hollow core contribute to the fiber strain sensor's high sensitivity (factor of 6.2 and 15.1 pF for revised sensitivity), negligible hysteresis, and durability over 10,000 stretching cycles. To ensure biocompatibility and immune tolerance during extended in vivo periods, an antibiofouling lubricant layer was applied to the sensing suture. Using this sensing system, we successfully monitored the strain responses of the reconstructed AT in an in vivo porcine model. This facilitated the postoperative assessment of mechanical stiffness variations through a well-established analytical model during the healing period.

Total rupture of Achilles tendon induces inflammatory response and glial activation on the spinal cord of mice

Rupture of Achilles tendon is a common accident affecting professional and recreational athletes. Acute and chronic pain are symptoms commonly observed in patients with rupture. However, few studies have investigated whether Achilles tendon rupture is able to promote disorders in the central nervous system (CNS). Therefore, the current study aimed to evaluate nociceptive alterations and inflammatory response in the L5 lumbar segment of Balb/c mice spinal cord after Achilles tendon rupture. We found increased algesia in the paw of the ruptured group on the 7th and 14th days post-tenotomy compared with the control group. This phenomenon was accompanied by overexpression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase-2 (NOS-2) as well as hyperactivation of astrocytes and microglia in nociceptive areas of L5 spinal cord as evidenced by intense GFAP and IBA-1 immunostaining, respectively. Biochemical studies also demonstrated increased levels of nitrite in the L5 spinal cord of tenotomized animals compared with the control group. Thus, we have demonstrated for the first time that total rupture of the Achilles tendon induced inflammatory response and nitrergic and glial activation in the CNS in the L5 spinal cord region.

Case study: The influence of Achilles tendon rupture on knee joint stress during counter-movement jump - Combining musculoskeletal modeling and finite element analysis

BACKGROUND

Presently, the current research concerning Achilles tendon rupture repair (ATR) is predominantly centered on the ankle joint, with a paucity of evidence regarding its impact on the knee joint. ATR has the potential to significantly impede athletic performance and increase tibiofemoral contact forces in athletes. The purpose of this study was to prognosticate the distribution of stress within the knee joint during a countermovement jump through the use of a simulation method that amalgamated a musculoskeletal model of a patient who underwent Achilles tendon rupture repair with a finite element model of the knee joint.

METHODS

A male elite badminton player who had suffered an acute Achilles tendon rupture in his right leg one year prior was selected as our study subject. In order to analyze his biomechanical data, we employed both the OpenSim musculoskeletal model and finite element model to compute various parameters such as joint angles, joint moments, joint contact forces, and the distribution of knee joint stress.

RESULTS

During the jumping phase, a significantly lower knee extension angle (p < 0.001), ankle dorsiflexion angle (p = 0.002), peak vertical ground reaction force (p < 0.001), and peak tibiofemoral contact force (p = 0.009) were observed on the injured side than on the uninjured side. During the landing phase, the ankle range of motion (ROM) was significantly lower on the injured side than on the uninjured side (p = 0.009), and higher peak vertical ground reaction forces were observed (p = 0.012). Additionally, it is logical that an injured person will put higher load on the uninjured limb, but the finite element analysis indicated that the stresses on the injured side of medial meniscus and medial cartilage were significantly greater than the uninjured side.

CONCLUSIONS

An Achilles tendon rupture can limit ankle range of motion and lead to greater joint stress on the affected area during countermovement jumps, especially during the landing phase. This increased joint stress may also transfer more stress to the soft tissues of the medial knee, thereby increasing the risk of knee injury. It is worth noting that this study only involves the average knee flexion angle and load after ATR in one athlete. Caution should be exercised when applying the conclusions, and in the future, more participants should be recruited to establish personalized knee finite element models to validate the results.

Muscle fascicle and sarcomere adaptation in response to Achilles tendon elongation in an animal model

Permanent loss of muscle function seen after an Achilles tendon rupture may partly be explained by tendon elongation and accompanying shortening of the muscle. Muscle fascicle length shortens, serial sarcomere number is reduced, and the sarcomere length is unchanged after Achilles tendon transection (ATT), and these changes are mitigated with suturing. The method involved in this study was a controlled laboratory study. Two groups of rats underwent ATT on one side with a contralateral control (CTRL): A) ATT with 3 mm removal of the Achilles tendon and no suturing (substantial tendon elongation), and B) ATT with suture repair (minimal tendon elongation). The operated limb was immobilized for 2 wk to reduce load. Four weeks after surgery the rats were euthanized, and hindlimbs were analyzed for tendon length, gastrocnemius medialis (GM) muscle mass, length, fascicle length, sarcomere number and length. No differences were observed between the groups, and in both groups the Achilles tendon length was longer (15.2%, P < 0.001), GM muscle mass was smaller (17.5%, P < 0.001), and muscle length was shorter (8.2%, P < 0.001) on the ATT compared with CTRL side. GM fascicle length was shorter (11.2%, P < 0.001), and sarcomere number was lower (13.8%, P < 0.001) on the ATT side in all regions. Sarcomere length was greater in the proximal (5.8%, P < 0.001) and mid (4.2%, P = 0.003), but not distal region on the ATT side. In this animal model, regardless of suturing, ATT resulted in tendon elongation, loss of muscle mass and length, and reduced serial sarcomere number, which resulted in an "overshoot" lengthening of the sarcomeres.NEW & NOTEWORTHY Following acute Achilles tendon rupture, patients are often left with functional deficits. The specific reason remains largely unknown. The shortened muscle leads to reduced fascicle length, in turn leading to adaptation by reduced serial sarcomere numbers. Surprisingly, this adaptation appears to "overshoot" and lead to increased sarcomere length. The present animal model advances understanding of how muscle sarcomeres, which are difficult to measure in humans, are affected when undue elongation takes place after tendon rupture.

In Vivo Strain Patterns in the Achilles Tendon During Dynamic Activities: A Comprehensive Survey of the Literature

Achilles' tendon (AT) injuries such as ruptures and tendinopathies have experienced a dramatic rise in the mid- to older-aged population. Given that the AT plays a key role at all stages of locomotion, unsuccessful rehabilitation after injury often leads to long-term, deleterious health consequences. Understanding healthy in vivo strains as well as the complex muscle-tendon unit interactions will improve access to the underlying aetiology of injuries and how their functionality can be effectively restored post-injury. The goals of this survey of the literature with a systematic search were to provide a benchmark of healthy AT strains measured in vivo during functional activities and identify the sources of variability observed in the results. Two databases were searched, and all articles that provided measured in vivo peak strains or the change in strain with respect to time were included. In total, 107 articles that reported subjects over the age of 18 years with no prior AT injury and measured while performing functional activities such as voluntary contractions, walking, running, jumping, or jump landing were included in this review. In general, unclear anatomical definitions of the sub-tendon and aponeurosis structures have led to considerable confusion in the literature. MRI, ultrasound, and motion capture were the predominant approaches, sometimes coupled with modelling. The measured peak strains increased from 4% to over 10% from contractions, to walking, running, and jumping, in that order. Importantly, measured AT strains were heavily dependent on measurement location, measurement method, measurement protocol, individual AT geometry, and mechanical properties, as well as instantaneous kinematics and kinetics of the studied activity. Through a comprehensive review of approaches and results, this survey of the literature therefore converges to a united terminology of the structures and their common underlying characteristics and presents the state-of-knowledge on their functional strain patterns.

Achilles tendon gait dynamics after rupture: A three-armed randomized controlled trial comparing an individualized treatment algorithm vs. operative or non-operative treatment

BACKGROUND

Individual treatment selection has been proposed as the key to optimized treatment. The purpose was to investigate if treatment selection using the individualized treatment algorithm Copenhagen Achilles Rupture Treatment Algorithm (CARTA) differs between patients treated as usual regarding gait dynamics and tendon elongation.

METHODS

The patients were randomized to one of three parallel groups: 1) intervention group: participants treated according to CARTA, 2) control group: participants treated non-operatively, 3) control group: participants treated operatively. The primary outcome was ankle peak power during push off during walking at 12 months.

RESULTS

156 patients were assessed for eligibility. 21 were allocated to the intervention group, and 20 and 19 to the control groups. The results indicated no statistically significant differences between the intervention group and the control groups.

CONCLUSIONS

Individualized treatment selection based on CARTA did not demonstrate less affected gait dynamics or less tendon elongation than patients treated as usual.

1.7 cm elongated Achilles tendon did not alter walking gait kinematics 4.5 years after non-surgical treatment

PURPOSE

The aim of the present study was to evaluate Achilles tendon length after non-surgical treatment of acute Achilles tendon rupture (aATR), and to evaluate indirect effects of possible persistent elongation on kinematics.

METHODS

The study was performed as a cross-sectional study based on a population of patients from an RCT regarding non-operative treatment of aATR. Thirty-seven patients out of the 56 in the original RCT participated with at a follow up of 4-5 years after aATR. Primary outcome was Achilles tendon elongation. Additional outcomes were Achilles tendon resting angle (ATRA), calf circumference, passive ankle plantar and dorsiflexion and loading pattern. Foot pressure mapping was performed to measure plantar loading distribution pattern; medial and lateral forefoot peak pressure, heel peak pressure, medial versus lateral loading pattern and timing of heel lift during roll over process. The healthy leg was used as a control.

RESULTS

The injured Achilles tendon was significantly elongated by 1.7 (SD 1.6) cm compared to the non-injured leg. A slight delay of 2.6% (SD 6.0) was measured in heel lift in the injured side compared to the non-injured leg. We found no significant difference in forefoot peak pressure, medial and lateral peak pressure as well as heel peak pressure, and no correlation was found between Achilles tendon length and pressure measurements. Finally, dorsiflexion was 1.9°(SD1.28) larger, ATRA 8.1°(SD6.7) larger, and calf circumference 1.6 cm (SD1.1) lower on the injured leg.

CONCLUSION

The Achilles tendon was 1.7 cm elongated 4.5 years after the initial injury and significant changes in ATRA, calf circumference and passive dorsiflexion was present. Except for a slight delay in heel lift-off, kinematics during walking was symmetrical between injured and healthy leg, even with an elongated tendon on the injured leg. The clinical relevance of the Achilles tendon elongation is uncertain.

LEVEL OF EVIDENCE

II.

CLINICAL TRIALS IDENTIFIER

NCT02760784.

No effects of early functional mobilization on gait patterns after acute Achilles tendon rupture repair

This study aimed to compare recovery of gait patterns in patients treated with early functional mobilization (EFM) or standard treatment (ST) after Achilles tendon rupture repair. Second, this study aimed to explore associations between gait patterns and tendon elongation and calf muscle atrophy, respectively. Forty-seven patients (12 females), mean age 38.7 (7.3) years, were included. Patients were postoperatively randomized to EFM (n = 29), including immediate weightbearing and ankle motion for 6 weeks, or ST (n = 18), with 2 weeks of unloading in a plaster cast followed by 4 weeks of weightbearing in an orthosis. Three-dimensional gait analyses were performed at 8 weeks and 6 months postoperatively to evaluate ankle and knee kinematics and kinetics. Ultrasound imaging was performed to assess tendon length and calf muscle atrophy. At 8 weeks, there were no significant group differences in ankle and knee kinematics and kinetics, while side-to-side differences between injured and uninjured side were present within both groups. At 6 months, the ST group exhibited higher generating ankle power and greater peak moments in ankle and knee compared to the EFM group. In both groups, peak ankle dorsiflexion angle was greater on the injured side compared to the uninjured side. No correlations were found between ankle joint gait deviations and degree of tendon elongation or muscle atrophy. Clinical significance: The accelerated rehabilitation regimen with EFM did not result in a more symmetrical gait pattern. The gait pattern deviations in the ankle joint were not related to the degree of muscle atrophy or tendon elongation.

Persistent Deficits after an Achilles Tendon Rupture: A Narrative Review

Persistent muscle weakness, tendon elongation, and incomplete return to preinjury level are frequent sequelae after acute Achilles tendon rupture, and evidence-based knowledge of how to best rehabilitate the injury is largely absent in the literature. The objective of this review is to illuminate and discuss to what extent an Achilles tendon rupture affects muscle, tendon, and function when assessed with the Achilles tendon total rupture score (ATRS), muscle strength, muscle cross-sectional area, tendon length, and the heel-rise test. The patient-reported outcome measures (PROM) data in the literature suggest that the recovery takes longer than 6 months (ATRS, 70 out of 100), that one-year postinjury, the ATRS only reaches 82, and that this does not appear to noticeably improve thereafter. Loss of muscle mass, strength, and function can in some cases be permanent. Over the first 6 months postinjury, the tendon undergoes elongation, which appears to be negatively correlated to heel-rise function. More recently, there has been some interest in how muscle length and excursion is related to the reduced function. The available literature indicates that further research is highly warranted and that efforts to restore normal tendon length may improve the likelihood of returning to preinjury level after an Achilles tendon rupture.

Greater heel-rise endurance is related to better gait biomechanics in patients surgically treated for chronic Achilles tendon rupture

PURPOSE

To determine the relationships among calf muscle function, tendon length and gait biomechanics in patients surgically treated for chronic Achilles tendon rupture.

METHODS

Twenty-one patients with chronic Achilles tendon rupture (mean age 62 ± 13 years) were evaluated by heel-rise endurance test, Achilles Tendon Resting Angle (ATRA), ultrasound measurement of tendon length and three-dimensional gait analysis. A bivariate two-sided correlation test was performed on all variables in all patients.

RESULTS

Better performance across all parameters of the heel-rise endurance test correlated with faster walking speed (r = 0.52-0.55), greater peak ankle power (r = 0.56-0.64), shorter stance phase (r = -0.52 to -0.76) and less peak ankle dorsiflexion angle (r = -0.49 to -0.64) during gait. Greater ATRA correlated with longer stance time (r = 0.47), greater peak ankle dorsiflexion angle (r = 0.48), less heel-rise repetitions (r = -0.52) and less heel-rise total work LSI (r = -0.44 to -0.59).

CONCLUSION

Greater calf muscle endurance, especially heel-rise total work, is moderately correlated (r = 0.49-0.76) to better ankle biomechanics during gait in patients surgically treated for CATR. The heel-rise endurance test may be a clinical proxy for power development in the ankle joint during gait.

LEVEL OF EVIDENCE

IV.

Modified triple Kessler with least risk of elongation among Achilles tendon repair techniques: a systematic review and network meta-analysis of human cadaveric studies

PURPOSE

Current treatment recommendations emphasize early loading, with preservation of tendon length and physiologic tension. The objective of this systematic review and network meta-analysis was to compare failure load and elongation after cyclic loading of Achilles tendon repair techniques at time-zero.

METHODS

The databases PubMed, CENTRAL and Web of Science were searched for all published in-vitro studies comparing Achilles tendon repair techniques, or augmentation with autografts/biomaterials, and reports of failure load or elongation after cyclic loading. Only studies using human cadaveric Achilles tendons and matched pairs, or randomized specimen allocation, were selected for quantitative synthesis. A network meta-analysis per primary outcome was performed. Results were summarized as P score rankings and their validity was assessed using statistical methods.

RESULTS

Sixteen studies, comprising 367 tendon repairs, were included. The following repair techniques were used (n = number of studies): Krackow (n = 8), Achillon (n = 4), double Krackow (n = 3), Bunnell (n = 3), Percutaneous Achilles Repair System (n = 3), Percutaneous Achilles Repair System Midsubstance (n = 2), Kessler (n = 3), double Kessler (n = 1), modified triple Kessler (n = 1), triple bundle (n = 1), a multifilament stainless steel cable-crimp technique (n = 1) and a double loop knot stitch (n = 1). Five studies assessed augmentation with autografts/biomaterials. Regarding the failure load, biomaterial augmented Krackow repairs occupied the first four positions in the ranking, followed by the multifilament stainless steel cable-crimp and Percutaneous Achilles Repair System Midsubstance techniques. Concerning elongation after cyclic loading, the triple Kessler was ranked first, followed by the Achillon and Percutaneous Achilles Repair System Midsubstance techniques. A negligible correlation between ranks was found (r_s = 0.11; p = 0.75n.s.), meaning that a higher repair tensile strength is not necessarily related to improved performance in regard to avoidance of elongation.

CONCLUSION

In the failure load network meta-analysis, biomaterial augmented Krackow repairs ranked highest, but noticeable statistical heterogeneity was found. Regarding elongation with cyclic loading, the modified triple Kessler stitch showed the highest probability of ranking first.

LEVEL OF EVIDENCE

Level IV.

Achilles tendon elongation after acute rupture: is it a problem? A systematic review

PURPOSE

Rupture of the Achilles tendon (AT) is a common injury. Strength deficits may persist over the long term, possibly owing to elongation of the tendon or inferior mechanical properties. This study aimed to provide a systematic review of the literature on the prevalence and consequences of tendon elongation in patients after acute AT rupture treatment. It was hypothesized that an elongated tendon would be associated with a worse clinical outcome.

METHODS

The databases for MEDLINE, CENTRAL and Web of Science were searched. Clinical studies related to AT rupture reporting tendon elongation and clinical or functional outcomes, with a minimum follow-up of 6 months, were eligible for inclusion. Only studies testing for statistical correlations (SCs) between AT elongation and other outcomes were eligible, with the exception of biomechanical studies in which statistically significant AT elongation was found to be a generalized finding in the study group. For these studies to be eligible, the study group had to be compared with a healthy control group, or the injured limb compared with the uninjured limb, regarding biomechanical parameters.

RESULTS

Twenty-eight papers were selected for inclusion. Mean AT elongation measured with imaging techniques ranged from 0.15 to 3.1 cm (n = 17). Ten studies investigated SCs with Patient Reported Outcome Measures (PROMs), in which two found SCs with tendon elongation. Five studies reported strength and power evaluations and their correlation with AT elongation, with two having found SCs between decreased strength and tendon elongation. In ten studies reporting data on biomechanical tests, nine found influence of tendon elongation. In this group, four out of five studies found SCs with biomechanical parameters.

CONCLUSION

Fair evidence of the influence of tendon elongation in biomechanical parameters was found. In a general population, evidence of a detrimental effect of tendon elongation on PROMs or functional strength at follow-up was not found in this review.

LEVEL OF EVIDENCE

Level IV.

Morphological and functional outcomes of operatively treated Achilles tendon ruptures

Objectives: Achilles tendon rupture leads to functional impairments and these may be underpinned by morphological changes in the muscle-tendon unit. The functional performance of the injured limb will be impaired regardless of time since surgery and these impairments occur alongside changes in muscle-tendon morphology. Methods: Following operative treatment of Achilles tendon rupture and short-term immobilization, 12 patients completed a battery of tests during a single visit to the laboratory (performed an average of 4.4 ± 2.6 years post-surgery). Patients completed the Achilles' tendon rupture score (ATRS), tests of the ankle and hip range of motion (ROM) and ultrasound measurements of muscle-tendon architecture. Data on isokinetic (30°/s, 60°/s) plantar flexion strength, jumping performance and walking-running were also collected on the same visit. Percentage deficits were expressed relative to the non-injured limb and determined for statistical significance (p < 0.05). Relationships between outcome measures and time since surgery were tested using Pearson's correlation coefficients (p < 0.05). Results: The repaired limb showed a shorter muscle fascicle length (12.1-19.6%), increased fascicle pennation (18.0 ± 22.14%) and reduced muscle thickness (9.1-20.1%) in the gastrocnemius and/or soleus along with greater tendon cross-sectional area (46.7 ± 34.47%). Functionally, the repaired limb displayed lower countermovement jump height (-12.6 ± 15.68%) and longer drop jump contact times (5.5 ± 5.7%). Also, the repaired limb showed reduced hip internal-external ROM (6.3 ± 8.2%) but no differences existed between limbs for plantar flexion ROM and strength or gait characteristics. Good ATRS outcomes were reported (mean: 87.9 ± 16.2, range: 43-100) which related to time since surgery (r = 0.79) but individual ATRS items did not correlate with corresponding objective measures. Conclusion: Plantar flexor atrophy following surgically treated Achilles tendon rupture is partially compensated for by remodeling of the fascicles; however, impairments may still persist many years into the postoperative period although these may be more pronounced in high-velocity activities.

Age and Tightness of Repair Are Predictors of Heel-Rise Height After Achilles Tendon Rupture

Background:

Achilles tendon rupture leads to weakness of ankle plantarflexion. Treatment of Achilles tendon rupture should aim to restore function while minimizing weakness and complications of management.

Purpose:

To determine the influence of factors (age, sex, body mass index [BMI], weight, time from injury to operative repair, and tightness of repair) in the initial surgical management of patients after an acute Achilles tendon rupture on 12-month functional outcome assessment after percutaneous and minimally invasive repair.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

From May 2012 to January 2018, patients sustaining an Achilles tendon rupture receiving operative repair were prospectively evaluated. Tightness of repair was quantified using the intraoperative Achilles tendon resting angle (ATRA). Heel-rise height index (HRHI) was used as the primary 12-month outcome variable. Secondary outcome measures included Achilles tendon total rupture score (ATRS) and Tegner score. Stepwise multiple regression was used to create a model to predict 12-month HRHI.

Results:

A total of 122 patients met the inclusion criteria for data analysis (mean ± SD age, 44.1 ± 10.8 years; 78% male; mean ± SD BMI, 28.1 ± 4.3 kg/m²). The elapsed time to surgery was 6.5 ± 4.0 days. At 12-month follow-up, patients had an HRHI of 82% ± 16% and performed 82% ± 17% of repetitions compared with the noninjured side. Participants had a mean ATRS of 87 ± 15 and a median Tegner score of 5 (range, 1-9), with a reduction in Tegner score of 2 from preinjury levels. The relative ATRA at 12 months was –4.8° ± 3.9°. Multiple regression identified younger age (B = ±0.006; P < .001) and greater intraoperative ATRA (B = 0.005; P = .053) as predictors of more symmetrical 12-month HRHI (R² = 0.19; P < .001; n = 120).

Conclusion:

Age was found to be the strongest predictor of outcome after Achilles tendon rupture. The most important modifiable risk factor was the tightness of repair. It is recommended that repair be performed as tight as possible to optimize heel-rise height 1 year after Achilles tendon rupture and possibly to reduce tendon elongation.

Proximal and Distal Failure Site Analysis in Percutaneous Achilles Tendon Rupture Repair

BACKGROUND

Different techniques have been described for percutaneous Achilles tendon rupture repair, but no biomechanical evaluation has been performed separately for proximal and distal suturing techniques. The purpose of this study was to biomechanically analyze proximal versus distal percutaneous Achilles suture configurations during cyclic loading and load to failure.

METHODS

A simulated, midsubstance rupture was created 6 cm proximal to the calcaneal insertion in fresh-frozen cadaveric Achilles tendons. Fifteen proximal specimens were divided into 3 groups: (A1) triple locking technique, (A2) Bunnell-type technique, and (A3) double Bunnell-type technique. Twelve distal specimens were divided into 2 groups: (B1) triple nonlocking technique and (B2) oblique technique. Repairs were subjected to cyclic testing and load to failure. Load to failure, cause of failure, and tendon elongation were evaluated.

RESULTS

None of the proximal specimens and 7/12 of the distal ones failed in cyclic testing. The proximal fixation groups demonstrated significantly more strength than the distal groups (P = .001), achieving up to 710 N of failure load in Group A3. Groups B1and B2 failed on average at 380 N with no difference between them (P > .05). The majority of all repairs failed in the suture-tendon interface. Distal groups had more elongation during cyclic testing (13.7 mm) than proximal groups (9.4 mm) (P = .02).

CONCLUSION

The distal fixation site in this Achilles tendon repair was significantly weaker than the proximal fixation site. A proximal modified suture configuration increased resistance to cyclic loading and load to failure significantly.

CLINICAL RELEVANCE

A modification can be suggested to improve strength of the Achilles repair.