Tendon Length Research Articles

Investigation of the Tissue Degenerative Impact of Increased BMI in Achilles Tendon via Strain Elastography and Finite Element Analysis.

This study is focused on establishing a relationship between poor muscle activity faced by obese individuals due to the change in stiffness of the intramuscular mass of the lower limb. This issue is also common among athletes and physically active teenagers. The study is aimed at a subject assessment diagnosis technique named as Strain Elastography (SE) to measure muscle strain. Further, Finite Element Modelling (FEM) technique is used to investigate the strain and/or deformations generated in the Achilles Tendon (AT) models, which were categorized according to their Body Mass Index (BMI) through computationally applied loadings. Total 54 volunteers with an average age of 21.85 ± 1.28 years were categorized into three groups according to their BMI (kg/m2); under BMI < 18.5 (n=14), normal BMI = 18.5-24.9 (n=20) and over BMI/obese > 25.0 (n=20). Additionally, multiple correlational analyses were performed between full range of BMI values and SE outcome. The presence of significant difference (p<0.05) was measured between different categories for BMI, BFMI, FFMI, DLFC, tendon length, tendon thickness and SR. Moreover, multiple correlational analyses and scatter plot strengthen the results. For FEM simulations, the maximum deformation was observed at the proximal end of the tendon in all three groups. It can be concluded that change in tendon stiffness and the resulting change in tendon structure was visualized with increased BMI. Moreover, obese individuals are more prone to tendon injury due to the increment in tendon thickness which causes bulging of the AT due to higher loads.

Is the muscle–tendon architecture of non-athletic Kenyans different from that of Japanese and French males?

BackgroundIn endurance running, elite Kenyan runners are characterized by longer thigh, shank, and Achilles tendon (AT) lengths combined with shorter fascicles and larger medial gastrocnemius (MG) pennation angles than elite Japanese runners. These muscle-tendon characteristics may contribute to the running performance of Kenyans. Furthermore, these specific lower-leg musculoskeletal architectures have been confirmed not only in elite Kenyan runners but also in non-athletic Kenyans since early childhood. However, it remains questionable whether the differences in muscle-tendon architecture between Kenyans and Japanese differ from those of European Caucasians. Therefore, this study aimed to compare anthropometry and muscle–tendon architecture of young non-athletic Kenyan males with their Japanese and French counterparts.MethodsA total of 235 young non-athletic males, aged 17–22 years, volunteered. The anthropometric measures, thigh, and shank lengths, as well as AT and MG muscle architecture, were measured using ultrasonography and a tape measure. Inter-group differences in anthropometry and muscle-tendon architecture were tested using one-way ANOVA and ANCOVA analyses controlling for shank length and muscle thickness.ResultsThe anthropometric and muscle-tendon characteristics of the non-athletic French were closer to those of the Kenyans than to those of the Japanese. However, the ultrasonography analysis confirmed that the non-athletic Kenyans had the longest AT as well as the shortest MG fascicles and the largest pennation angle compared to the French and Japanese, even after controlling for shank length and muscle thickness with ANCOVA, respectively.ConclusionsThese results confirmed the specificity of the muscle-tendon architecture of the triceps surae in Kenyans in comparison to their Japanese and French counterparts in non-athletic adults. This study provides additional support to the fact that Kenyans may have musculotendinous advantages in endurance running.

Lie Group Formulation and Sensitivity Analysis for Shape Sensing of Variable Curvature Continuum Robots With General String Encoder Routing

This article considers a combination of actuation tendons and measurement strings to achieve accurate shape sensing and direct kinematics of continuum robots. Assuming general string routing, a methodical Lie group formulation for the shape sensing of these robots is presented. The shape kinematics is expressed using arc-length-dependent curvature distributions parameterized by modal functions, and the Magnus expansion for Lie group integration is used to express the shape as a product of exponentials. The tendon and string length kinematic constraints are solved for the modal coefficients and the configuration space and body Jacobian are derived. The noise amplification index for the shape reconstruction problem is defined and used for optimizing the string/tendon routing paths, and a planar simulation study shows the minimal number of strings/tendons needed for accurate shape reconstruction. A torsionally stiff continuum segment is used for experimental evaluation, demonstrating mean (maximal) end-effector absolute position error of less than 2% (5%) of total length. Finally, a simulation study of a torsionally compliant segment demonstrates the approach for general deflections and string routings. We believe that the methods of this article can benefit the design process, sensing, and control of continuum and soft robots.

Evaluation of patellar tendon morphology in Turkish population: a cross-sectional study

Aim: This study aims to investigate the length, width and thickness of the patellar tendon and the type and length of the patella with MRI and to reveal the normal values ​​of patellar tendon morphology specific to the Turkish population.&#x0D; Material and Method: The study was conducted with 348 individuals (137 males, 211 females) who applied to our hospital, had no anterior knee pathology, and had knee MRIs. The length, proximal and distal width and thickness of the patellar tendon, patella type, prepatellar and infrapatellar fat pad signal characteristics and Insall-Salvati ratio were evaluated on knee MRI images of these individuals.&#x0D; Results: Type I patella was detected in 23.9%, type II in 57.2%, type III in 16.1%, and type IV in 2.9% of individuals. The mean length of the patella was 41.26±4.36 mm, the patellar tendon length was 47.36±6.70 mm, the proximal width was 28.86±3.49 mm, the distal width was 23.53±2.69 mm, the proximal thickness was 3,62±1.47 mm, and distal thickness was 5.21±1.1 mm. It was determined that the Insall-Salvati ratio did not cause a statistical difference according to age, but the patella type showed significance with the Insall-Salvati classification.&#x0D; Conclusion: While evaluating MRI images, the effect of social differences on measurements should not be ignored; normal measurement values ​​of the tendon should be known to evaluate pathological measurements.

PIEZO1 gain-of-function gene variant is associated with elevated tendon stiffness in humans.

Prolonged periods of increased physical demands can elicit anabolic tendon adaptations that increase stiffness and mechanical resilience or conversely can lead to pathological processes that deteriorate tendon structural quality with ensuing pain and potential rupture. Although the mechanisms by which tendon mechanical loads regulate tissue adaptation are largely unknown, the ion channel PIEZO1 has been implicated in tendon mechanotransduction, with human carriers of the PIEZO1 gain-of-function variant E756del displaying improved dynamic vertical jump performance compared to noncarriers. Here, we sought to examine whether increased tendon stiffness in humans could explain this increased performance. We assessed tendon morphological and mechanical properties with ultrasound-based techniques in 77 participants of Middle- and West-African descent, and we measured their vertical jumping performance to assess potential functional consequences in the context of high tendon strain-rate loading. Carrying the E756del gene variant (n = 30) was associated with 46.3 ± 68.3% (p = 0.002) and 45.6 ± 69.2% (p < 0.001) higher patellar tendon stiffness and Young's modulus compared to non-carrying controls, respectively. While these tissue level measures strongly corroborate the initial postulate that PIEZO1 plays an integral part in regulating tendon material properties and stiffness in humans, we found no detectable correlation between tendon stiffness and jumping performance in the tested population that comprised individuals of highly diverse physical fitness level, dexterity, and jumping ability.

Rotator cuff repair with an interposition polypropylene mesh: A biomechanical ovine study.

Chronic large to massive rotator cuff tears are difficult to treat and re-tears are common even after surgical repair. We propose using a synthetic polypropylene mesh to increase the tensile strength of rotator cuff repairs. We hypothesize that using a polypropylene mesh to bridge the repair of large rotator cuff tears will increase the ultimate failure load of the repair. To investigate the mechanical properties of rotator cuff tears repaired with a polypropylene interposition graft in an ovine ex-vivo model. A 20 mm length of infraspinatus tendon was resected from fifteen fresh sheep shoulders to simulate a large tear. We used a polypropylene mesh as an interposition graft between the ends of the tendon for repair. In seven specimens, the mesh was secured to remnant tendon by continuous stitching while mattress stitches were used for eight specimens. Five specimens with an intact tendon were tested. The specimens underwent cyclic loading to determine the ultimate failure load and gap formation. The mean gap formation after 3000 cycles was 1.67 mm in the continuous group, and 4.16 mm in the mattress group (P = 0.001). The mean ultimate failure load was significantly higher at 549.2 N in the continuous group, 426.4 N in the mattress group and 370 N in the intact group (P = 0.003). The use of a polypropylene mesh is biomechanically suitable as an interposition graft for large irreparable rotator cuff tears.

The adductor magnus tendon is a viable option for medial patellofemoral ligament reconstruction, but with a busy surrounding neurovascular topography.

To describe the proximity of the neurovascular structures surrounding the adductor magnus (ADM), to delineate a safe boundary focusing on the techniques used during graft harvest and to evaluate whether the length of the ADM tendon is sufficient for safe medial patellofemoral ligament (MPFL) reconstruction. Sixteen formalin-fixed cadavers were dissected. The area surrounding the ADM, the adductor tubercle (AT) and the adductor hiatus was exposed. The following measurements were performed: the (1) total length of MPFL, (2) distance between the AT and the saphenous nerve, (3) the point where the saphenous nerve pierces the vasto-adductor membrane, (4) the point where the saphenous nerve crosses the ADM tendon, (5) the musculotendinous junction of the ADM tendon, and (6) the point where the vascular structures exit the adductor hiatus. Additionally, (7) the distance between the ADM musculotendinous junction and the nearest vessel (popliteal artery), (8) the distance between the ADM (at the level where the saphenous nerve crosses) and the nearest vessel, (9) the length between the AT and the superior medial genicular artery, and finally (10) the depth between the AT and the superior medial genicular artery were analyzed. The in situ length of the native MPFL was 47.6 ± 42.2mm. The saphenous nerve pierces the vasto-adductor membrane at a mean distance of 100mm, although it crosses the ADM itself at an average of 67.6mm. The vascular structures, on the other hand, become vulnerable at a distance of 89.1 ± 114.0mm from the AT. After harvesting the ADM tendon, the mean length was found to be 46.9mm, which was insufficient for fixation. Partial release from the AT resulted in a more adequate length for fixation (65.4 ± 88.7mm). The adductor magnus tendon is a viable option for the dynamic reconstruction of the MPFL. Knowledge of the surrounding busy neurovascular topography is paramount for a procedure typically performed in a minimally invasive way. The study results are clinically relevant, as they suggest that tendons should be shorter than the minimum distance from the nerve. If in some cases the length of the MPFL is longer than the distance of the ADM from the nerve, the results suggest that a partial dissection of the anatomical structures might be needed. Direct visualization of the harvesting region might be considered in such cases.

Medial gastrocnemius muscle fascicle function during heel-rise after non-operative repair of Achilles tendon rupture

BackgroundTo better understand muscle remodelling in dynamic conditions after an Achilles tendon rupture, this study examined the length of medial gastrocnemius muscle fascicles during a heel-rise at 6- and 12-months after non-operative ATR treatment. MethodsParticipants (15 M, 3F) were diagnosed with acute Achilles tendon rupture. Medial gastrocnemius subtendon length, fascicle length and pennation angle were assessed in resting conditions, and fascicle shortening during bi- and unilateral heel-rises. FindingsFascicle shortening was smaller on the injured side (mean difference [95% CI]: −9.7 mm [−14.7 to −4.7 mm]; −11.1 mm [−16.5 to −5.8 mm]) and increased from 6- to 12 months (4.5 mm [2.8–6.3 mm]; 3.2 mm [1.4–4.9 mm]) in bi- and unilateral heel-rise, respectively. The injured tendon was longer compared to contralateral limb (2.16 cm [0.54–3.79 cm]) and the length decreased over time (−0.78 cm [−1.28 to −0.29 cm]). Tendon length correlated with fascicle shortening in bilateral (r = −0.671, p = 0.002; r = −0.666, p = 0.003) and unilateral (r = −0.773, p ≤ 0.001; r = −0.616, p = 0.006) heel-rise, at 6- and 12-months, respectively. In the injured limb, the change over time in fascicle shortening correlated with change in subtendon length in unilateral heel-rise (r = 0.544, p = 0.02). InterpretationThis study showed that the lengths of the injured tendon and associated muscle can adapt throughout the first year after rupture when patients continue physiotherapy and physical exercises. For muscle, measures of resting length may not be very informative about adaptations, which manifest themselves during functional tasks such as unilateral heel-rise.

Constant force muscle stretching induces greater acute deformations and changes in passive mechanical properties compared to constant length stretching

Stretching is applied to lengthen shortened muscles in pathological conditions such as joint contractures. We investigated (i) the acute effects of different types of stretching, i.e. constant length (CL) and constant force (CF) stretching, on acute deformations and changes in passive mechanical properties of medial gastrocnemius muscle (MG) and (ii) the association of acute muscle–tendon deformations or changes in mechanical properties with the impulse or maximal strain of stretching. Forty-eight hindlimbs from 13 male and 12 female Wistar rats (13 weeks old, respectively 424.6 ± 35.5 and 261.8 ± 15.6 g) were divided into six groups (n = 8 each). The MG was initially stretched to a length at which the force was 75%, 95%, or 115% of the force corresponding to estimated maximal dorsiflexion and held at either CF or CL for 30 min. Before and after the stretching protocol, the MG peak force and peak stiffness were assessed by lengthening the passive muscle to the length corresponding to maximal ankle dorsiflexion. Also, the muscle belly length and tendon length were measured. CF stretching affected peak force, peak stiffness, muscle belly length, and tendon length more than CL stretching (p < 0.01). Impulse was associated only with the decrease in peak force, while maximal strain was associated with the decrease in peak force, peak stiffness, and the increase in muscle belly length. We conclude that CF stretching results in greater acute deformations and changes in mechanical properties than CL stretching, which appears to be dependent predominantly on the differences in imposed maximal strain.

The Use of Plantaris Muscle Flap for Facial Reanimation: A Comprehensive Anatomical Study.

Background: Functional facial reanimation remains challenging and the quest for optimization continues. Objective: To characterize the anatomical conditions of the plantaris muscle for facial reanimation. Study Design and Methods: Forty-two plantaris muscle specimens were obtained from 23 post-mortem chemically fixed cadavers. The muscles were dissected, evaluated, and measured. Mock facial reanimation was performed on three cadaver heads. Results: The plantaris muscle was a consistently available muscle. Mean muscle belly length was 10.1 cm (standard deviation [SD] 1.4), and mean width was 1.7 cm (SD 0.4). The mean tendon length of 30.1 cm (SD 2.8) is unique in the human body. The main artery supplying the muscle had a mean length of 1.4 cm (SD 0.4). The mean nerve length was 2.2 cm (SD 0.7). Sixteen variations of vascular supply were identified. Mock facial reanimations demonstrated a good size match, and great versatility of the long tendon for oral fixation. Conclusions: The plantaris muscle as a free flap for facial reanimation could offer new possibilities in terms of oral fixation and volumetric aesthetic conditions.

ANKLE LIGAMENT REPAIR FOR RESTORATION OF FUNCTION: EXPLORING THE APPLICATION OF DECELLULARIZED GRAFTS

Ligament integrity is directly associated with ankle stability. Nearly 40% of ankle sprains result in chronic ankle instability, affecting biomechanics and potentially causing osteoarthritis. Ligament replacement could restore stability and avoid this degenerative pathway, but a greater understanding of ankle ligament behaviour is required. Additionally, autograft or allograft use is limited by donor-site morbidity and inflammatory responses respectively. Decellularised porcine grafts could address this, by removing cellular material to prevent acute immune responses, while preserving mechanical properties.This project will characterise commonly injured ankle ligaments and damage mechanisms, identify ligament reconstruction requirements, and investigate the potential of decellularised porcine grafts as a replacement material.Several porcine tendons were evaluated to identify suitable candidates for decellularisation. The viscoelastic properties of native tissues were assessed using dynamic mechanical analysis (DMA), followed by ramp to ‘sub-rupture’ at 1% strain/s, and further DMA. Multiple samples (n=5) were taken along the graft to assess variation along the tendon.When identifying suitable porcine tendons, a lack of literature on human ankle ligaments was identified. Inconsistencies in measurement methods and properties reported makes comparison between studies difficult.Preliminary testing on porcine tendons suggested there is little variation in viscoelastic properties along the length of tendon. Testing also suggested strain rates of 1%/s sub-rupture was not large enough to affect viscoelastic properties (no changes in storage or loss moduli or tanẟ). Further testing is underway to improve upon low initial sample numbers and confirm these results, with varying strain rates to identify suitable sub-rupture sprain conditions.This work highlights need for new data on human ankle ligaments to address knowledge gaps and identify suitable replacement materials. Future work will generate this data and decellularise porcine tendons of similar dimensions. Collagen damage will be investigated using histology and lightsheet microscopy, and viscoelastic changes through DMA.

Clinical and radiologic outcomes after tendon insertion medialized repair of large-to-massive rotator cuff tears

To evaluate the effectiveness of tendon insertion medialized repair in treatment of large-to-massive rotator cuff tears (L/MRCT). The clinical and imaging data of 46 L/MRCT patients who underwent arthroscopic insertion medialized repair between October 2015 and June 2019 were retrospectively analyzed. There were 26 males and 20 females with an average age of 57.7 years (range, 40-75 years). There were 20 cases of large rotator cuff tears and 26 cases of massive rotator cuff tears. Preoperative imaging evaluation included fatty infiltration (Goutallier grade), tendon retraction (modified Patte grade), supraspinatus tangent sign, acromiohumeral distance (AHD), and postoperative medializaiton length and tendon integrity. The clinical outcome was evaluated by visual analogue scale (VAS) score, American Society for Shoulder and Elbow Surgery (ASES) score, shoulder range of motion (including anteflexion and elevation, lateral external, and internal rotation) and anteflexion and elevation muscle strength before and after operation. The patients were divided into two groups (the intact tendon group and the re-teared group) according to the integrity of the tendon after operation. According to the medializaiton length, the patients were divided into group A (medialization length ≤10 mm) and group B (medialization length >10 mm). The clinical function and imaging indexes of the patients were compared. All patients were followed up 24-56 months, with an average of 31.8 months. At 1 year after operation, MRI showed that the medializaiton length of supraspinatus tendon was 5-15 mm, with an average of 10.26 mm, 33 cases in group A and 13 cases in group B. Eleven cases (23.91%) had re-teared, including 5 cases (45.45%) of Sugaya type Ⅳ and 6 cases (54.55%) of Sugaya type Ⅴ. At last follow-up, the VAS score, ASES score, shoulder anteflexion and elevation range of motion, lateral external rotation range of motion, and anteflexion and elevation muscle strength significantly improved when compared with those before operation ( P<0.05); there was no significant difference in internal rotation range of motion between pre- and post-operation ( P>0.05). The Goutallier grade and modified Patte grade of supraspinatus muscle in the re-teared group were significantly higher than those in the intact tendon group, and the AHD was significantly lower than that in the intact tendon group ( P<0.05). There was no significant difference in other baseline data between the two groups ( P>0.05). Except that the ASES score of the intact tendon group was significantly higher than that of the re-teared group ( P<0.05), there was no significant difference in the other postoperative clinical functional indicators between the two groups ( P>0.05). There was no significant difference in the incidence of re-tear, VAS score, ASES score, range of motion of shoulder joint, and anteflexion and elevation muscle strength between group A and group B ( P>0.05). Tendon insertion medialized repair may be useful in cases with L/MRCT, and shows good postoperative shoulder function. Neither tendon integrity nor medialization length shows apparent correlations with postoperative shoulder function.

Exploration of muscle–tendon biomechanics one year after Achilles tendon rupture and the compensatory role of flexor hallucis longus

Achilles tendon (AT) rupture leads to long-term structural and functional impairments. Currently, the predictors of good recovery after rupture are poorly known. Thus, we aimed to explore the interconnections between structural, mechanical, and neuromuscular parameters and their associations with factors that could explain good recovery in patients with non-surgically treated AT rupture. A total of 35 patients with unilateral rupture (6 females) participated in this study. Muscle-tendon structural, mechanical, and neuromuscular parameters were measured 1-year after rupture. Interconnections between the inter-limb differences (Δ) were explored using partial correlations, followed by multivariable linear regression to find associations between the measured factors and the following markers that indicate good recovery: 1) tendon length, 2) tendon non-uniform displacement, and 3) flexor hallucis longus (FHL) normalized EMG amplitude difference between limbs. Δmedial gastrocnemius (MG) (β = −0.12, p = 0.007) and Δlateral gastrocnemius (β = −0.086, p = 0.030) subtendon lengths were associated with MG tendon Δstiffness. MG (β = 11.56, p = 0.003) and soleus (β = 2.18, p = 0.040) Δsubtendon lengths explained 48 % of variance in FHL EMG amplitude. Regression models for tendon length and non-uniform displacement were not significant. Smaller inter-limb differences in Achilles subtendon lengths were associated with smaller differences in the AT stiffness between limbs, and a smaller contribution of FHL muscle to the plantarflexion torque. In the injured limb, the increased contribution of FHL appears to partially counteract a smaller contribution from MG due to the elongated tendon, however the role of FHL should not be emphasized during rehabilitation to allow recovery of the TS muscles.

RELATIONSHIP OF THE TRICEPS TENDON AND OLECRANON PLATES: AN ANATOMIC STUDY

Olecranon plates used for the internal fixation of complex olecranon fractures are applied directly over the triceps tendon on the posterior aspect of the olecranon. The aim of the study is to describe the relationship of the plates and screws to the triceps tendon at the level of the olecranon.Eight cadaveric elbows were used. Dimensions of the triceps tendon at the insertion and 1cm proximal were measured. A long or a short olecranon plate was then applied over the olecranon and the most proximal screw applied. The length of the plate impinging on the tendon and the level of the screw tract on the tendon and bone were measured.The mean olecranon height was 24.3cm (22.4-26.9cm) with a tip-to-tendon distance of 14.5cm (11.9-16.2cm). The triceps tendon footprint averaged 13.3cm (11.7-14.9cm) and 8.8cm (7.6-10.2cm) in width and length, respectively. The mean width of the central tendon 1 cm proximal to the footprint was 6.8 cm. The long olecranon plate overlay over more movable tendon length than did the short plate and consequently the superior screw pierced the triceps tendon more proximally with the long plate. Using the Mann-Whitney U test, the differences were significant.The long olecranon plates encroach on more triceps tendon than short plates. This may be an important consideration for olecranon fractures with regards implant loosening or triceps tendon injury.

Preoperative ultrasound can accurately predict the diameter of double-stranded peroneus longus tendon autografts.

This study aimed to determine the correlation between the intraoperative diameter of double-stranded peroneus longus tendon (2PLT) and length of the PLT autograft and preoperative ultrasound (US) measurements, as well as radiographic and anthropometric measurements. The hypothesis was that US can accurately predict the diameter of 2PLT autografts during operation. Twenty-six patients underwent ligament reconstruction with 2PLT autografts were included. Preoperative US was used to calculate the in situ PLT cross-sectional area (CSA) at seven levels (0, 1, 2, 3, 4, 5, 10cm proximal to the harvest start point). Femoral width, notch width, notch height, maximum patellar length, and patellar tendon length were determined on preoperative radiographs. Intraoperative measurements of PLT were made, including all fiber lengths of PLT and diameters of 2PLT using sizing tubes calibrated to 0.5mm. CSA at 1cm proximal to the harvest site had the highest correlation with the diameter of 2PLT (r = 0.84, P < 0.001). Calf length had the highest correlation with PLT length (r = 0.65, P < 0.001). The diameter of the 2PLT autografts could be predicted by the following formula: 4.6 + 0.2 × [sonographic CSA of PLT at 1cm level]; the length of PLT could be predicted by the following formula: 5.6 + 0.5 × Calf length. The diameter of 2PLT and length of PLT autografts can be accurately predicted by preoperative US and calf length measurements, respectively. Accurate preoperative prediction of the diameter and length of autologous grafts can provide the most suitable and individualized graft for patients. IV.

Measurements of tendon length changes during stretch–shortening cycles in rat soleus

The muscle force attained during concentric contractions is augmented by a preceding eccentric contraction (the stretch–shortening cycle (SSC) effect). At present, tendon elongation is considered the primary mechanism. However, we recently found that the magnitude of the SSC effect was not different, even after removing the Achilles tendon. To resolve these discrepant results, direct measurement of changes in Achille tendon length is required. Therefore, this study aimed to elucidate the influence of tendon elongation on the SSC effect by directly measuring the changes in Achilles tendon length. The rat soleus was subjected to pure concentric contractions (pure shortening trials) and concentric contractions with a preceding eccentric contraction (SSC trials). During these contractions, the Achilles tendon length was visualized using a video camera. The muscle force attained during the concentric contraction phase in the SSC trial was significantly larger than that in the pure shortening trial (p = 0.022), indicating the existence of the SSC effect. However, the changes in Achilles tendon length were not different between trials (i.e., the magnitude of tendon shortening attained during the shortening phase was 0.20 ± 0.14 mm for the SSC trial vs. 0.17 ± 0.09 mm for the pure shortening trial), indicating that the observed SSC effect is difficult to be explained by the elastic energy stored in tendons or muscle–tendon interaction. In conclusion, the effect of tendon elongation on the SSC effect should be reconsidered, and other factors may contribute to the SSC effect.

Acquired changes in thickness and length of patellar tendon after primary total knee arthroplasty: a prospective ultrasonographic study with over 4 years of follow-up.

Previous literature has reported changes in the length or thickness of the patellar tendon (PT) following primary total knee arthroplasty (TKA). This study aims to determine the structural changes in both the length and thickness of the PT after primary TKA using ultrasound (US) and to investigate the association between these changes and clinical outcomes after a minimum follow-up of 48 months. This prospective study used the US on 60 knees of 32 patients (aged 54-80, mean 64.8±7 years) before and after primary TKA to evaluate changes in both the length and thickness of the patellar tendon. Clinical outcomes were assessed with HSS and Kujala scores. At the latest follow-up evaluation, there was a significant overall shortening of PT by 9.1% (p<0.001), in addition to significant global thickening by 20% (p<0.001). Besides, there was significant thickening by 30% in the proximal 1/3 (p<0.01) and 27% in the middle 1/3 (p<0.01) segments of PT. There was a significant negative correlation between the thickening identified in all three parts of the tendon and both clinical outcome measures (p<0.05). The results show the presence significant changes in PT in terms of length and thickness after primary TKA; in addition, increased thickness in PT was more strongly and significantly associated with inferior clinical outcomes, including functionality and anterior knee pain, than shortness in PT. This study also suggests that the US is a viable, non-invasive method for documenting PT changes in both length and thickness after TKA with serial scans.

Thigh Length as the Most Consistent Anthropometric Parameter in Predicting the Size of Hamstring Tendon Autografts in Patients Undergoing Anterior Cruciate Ligament Reconstruction: A Cross-Sectional Study.

Individual variability in the length and thickness of hamstring tendon autografts is a serious drawback in using these tendons for anterior cruciate ligament reconstruction (ACLR). In this study, we aimed to determine the correlation between the anthropometric parameters and the size of hamstring tendon autografts. In a cross-sectional study, 52 male ACLR candidates were included. The length of semitendinosus and gracilis tendons and the diameter of single, doubled, and quadrupled tendons were measured. A graft sizing block device with an incremental size change of 0.5 mm (range 4.5-12) was used to measure the tendon graft diameter. The evaluated anthropometric parameters included age, gender, height, weight, BMI, thigh length and diameter, calf length, thigh-to-calf ratio, wrist diameter, and ankle diameter. A Pearson's or Spearman's correlation coefficient test was used for evaluating the correlation of anthropometric factors with graft characteristics. The mean age of the patients was 27.1 ± 6.4 years. The semitendinosus length was significantly correlated with the patient's height (r = 0.373, P = 0.007), thigh length (r = 0.364, P = 0.009), and calf length (r = 0.340, P = 0.015). The gracilis length was significantly correlated with thigh length (r = 0.278, P = 0.049). The mean quadruple diameter was 8.56 ± 1.15 mm (range 6.5-11). The quadruple diameter was significantly correlated with the thigh length (r = 0.283, P = 0.044). No other significant correlation was found between the tendons' size and evaluated anthropometric parameters. Thigh length was correlated with the semitendinosus length, gracilis length, and quadruple diameter. Therefore, it could be regarded as the most consistent and promising anthropometric factor in the prediction of hamstring autograft size.

Ultrasonographic Assessment of Normal Achilles Tendon Thickness and Width in the Asymptomatic Sudanese Population

Background: The goal of this study was to measure normal Achilles tendon (AT) thickness and width in adult asymptomatic Sudanese people using high-resolution ultrasound. Methods and Results: The study was conducted on members of a healthy Sudanese population (120 volunteers: 73/60.8% women and 47/39.2% men), who were chosen using simple random sampling. The study cases were all healthy people with no history of AT injuries or abnormalities. All patients were examined using a Toshiba Xairo200 linear transducer with a frequency range of 7-10MHz. All measurements were taken from a transverse scan at the calcaneus bone level of the AT insertion and 2 to 3cm above the calcaneus. The age group 20-27 had the most participants (44.2%), followed by 36-43 years (19.2%), 28-35 years (15.8%), 52-60 years (14.2%), and 44-51 years (6.7%). The study revealed that the mean age of participants was 34.19±12.29 years, height - 164±0.081 cm, weight - 67.22±15.97 kg, and BMI - 24.38±5.84 kg/m2. The mean thickness and width of the AT were 4.36±0.81 mm and 21.85±3.23 mm, respectively, at its insertion into the calcaneus, and 4.63±0.77 mm and 12.20±1.37 mm, respectively, at the level 2-3 cm above the insertion. We found significant differences according to gender between the AT thickness and width at insertion into the calcaneus and above insertion and no statistically significant differences between the AT measurement's right and left side data. Conclusion: The study found gender differences in the AT thickness and width at insertion into the calcaneus and 2-3 cm above the insertion. No statistically significant differences were detected between the AT measurement’s right and left side data.Age, weight, height, and BMI correlated with the thickness and width of the AT at its insertion into the calcaneus and 2-3 cm above. Furthermore, additional research should be conducted using an extended field-of-view technology to measure the length of the AT tendon in the Sudanese population.

Morphometry of the patellar tendon using a simple tracing method: a gold standard for anterior cruciate ligament reconstruction.

The anterior cruciate ligament (ACL) is mostly damaged in sporting activities. To reconstruct the damaged ACL, a patellar tendon (PT) is often the most preferred graft due to its fast healing and bone integration i.e. bone-patellar tendon-bone graft. Suitability of the PT often depends on the morphometric profile of the tendon. This study reported on the harvestable surface area (SA) of the tendon using a simple tracing method. The PT of 79 adult formalin-fixed cadavers of South Africans of European Ancestry were dissected, and the margins of the PT were traced on a wax paper before the tracings were scanned. The SA, straight proximal width (SPW), curved proximal width (CPW), straight distal width (SDW), curved distal width (CDW) and length of tendon (LOT) from the digitized image of the PT was measured. In addition, the length of the lower limbs was measured to normalize the measurements. The results showed no significant side differences, and the measurements were not sexually dimorphic. A strong correlation was reported for SA vs. LOT, SPW vs. CPW and SDW vs. CDW for both sexes and sides. The presented morphological profile provides additional information on the usability of the graft and with respect to healing and recovery.