Objective quantification of tendon structural changes through imaging is only achieved by evaluating tendon structure using ultrasound tissue characterization (UTC) technology. This study compares the effects of bone marrow mesenchymal stromal cells (BM-MSC) and leukocyte-poor platelet-rich plasma (Lp-PRP) on tendon structure and clinical outcomes in male patients with patellar tendinopathy measured with UTC at 3, 6, and 12 months after treatment. This is a double-blinded clinical trial with a randomized active control study with 20 male patients diagnosed with patellar tendinopathy who underwent BM-MSC and Lp-PRP. Bilateral ultrasound tissue characterization scans of the patellar tendon were carried out after 3, 6, and 12 months, as well as tests for strength and pain. UTC patellar tendon was analyzed at the insertion, proximal, and mid-tendon. BM-MSC showed a greater capacity to promote further positive changes than Lp-PRP. Lp-PRP presented higher disorganized echo-type II in the mid-tendon (p = 0.04; ES = 1.06) and III (p = 0.02; ES = -1.47) after 3 months in the Lp-PRP group. Similar results were seen after 6 and 12 months. Pain and strength data show improvement in the treated tendon. BM-MSC treatment demonstrates a superior capacity to promote tendon regeneration and organization, restore strength, and reduce pain compared to Lp-PRP, after 3, 6, and 12 months in male patients with patellar tendinopathy.

For decades, needling interventions have been performed based on manual palpation and anatomic knowledge. The increasing use of real-time ultrasonography in clinical practice has improved the accuracy and safety of needling techniques. Although currently ultrasound-guided procedures are routinely used for patellar tendon pathology, e.g., during percutaneous electrolysis, the accuracy of these procedures is still unknown. This study used a cadaveric model to compare and evaluate both the accuracy and safety of ultrasound-guided and palpation-guided needling techniques for the patellar tendon. A total of five physical therapists performed a series of 20 needle insertion task each (n = 100), 10 insertions based on manual palpation (n = 50) and 10 insertions guided with ultrasound (n = 50) to place a needle along the interface between the patellar tendon and Hoffa\'s fat pad. All procedures were performed on cryopreserved knee specimens. Distance to the targeted tissue, time of the procedure, accurate rate of insertions, number of passes, and unintentional punctured structures between both applications (with and without ultrasound guiding) were compared. The results revealed higher accuracy (100% vs. 80%), a lower distance from needle to the targeted tissue (0.25 ± 0.65 vs. 2.5 ± 1.9 mm), longer surface of contact with the needle (15.5 ± 6.65 vs. 4.7 ± 7.5 mm), and a lower frequency of patellar tendon puncture (16% vs. 52%, p < 0.001) with the ultrasound-guided procedure as opposed to palpation-guided one. Nevertheless, the ultrasound-guided procedure took longer (54.8 ± 26.8 vs. 23.75 ± 15.4 s) and required more passes (2.55 ± 1.9 vs. 1.5 ± 0.95) to be conducted than the palpation-guided procedure (all, p < 0.001). According to these findings, the accuracy of invasive procedures applied on the patellar tendon is higher when conducted with ultrasound guidance than when conducted just on manual palpation or anatomical landmark. These results suggest that ultrasound could improve the clinical application of invasive procedures at the fat-patellar tendon interface. Due to the anatomical features of the targeted tissue, some procedures require this precision, so the use of ultrasound is recommended.

The purpose of this study was to analyze the changes in the elasticity and temperature of the patellar tendon produced by the application of a radiofrequency at 448 kHz (CRMR) just after and 7 days after the intervention. An open controlled clinical trial was used with participants being recruited from a private clinic. The experimental group (n = 22) received a 448 kHz CRMR treatment while the control group (n = 22) did not receive any type of intervention. Quantitative ultrasound strain elastography (SEL) and thermography were used to collect data from 4 different areas of the patellar tendon. These areas were measured at the start (T0), just after (T1), and seven days after (T2) the intervention. There were thermal changes immediately after the intervention (p < 0.001). In addition, when the measurements were collected just after the intervention and seven days after they were analyzed, significant changes (p < 0.001) in temperature were observed in the tendons of both groups. Finally, a low but significant association (r = 0.434, p < 0.04) was observed between the elastic properties of the tendon at its insertion in the patella and thermal changes just after the 448 kHz intervention.

BACKGROUND: Adolescent patellar tendinopathy is reported but the pubertal-stage of onset of abnormal tendon structure has not been investigated with grayscale ultrasound.
OBJECTIVE: To investigate abnormal tendon structure using grayscale ultrasound and its association with pubertal-stage and pain.
METHODS: Forty-three male basketball players aged 13.7 years (SD 1.0) had patellar tendon ultrasound scans every 6 months for 2.5 years. Pubertal-stage (peak height velocity) was calculated using the Mirwauld equation. Tendon thickness, hypoechogenicity and pain during single leg decline squat (SLDS) were recorded. Tendons were classified: hypoechoic, normal or immature.
RESULTS: Two tendons were hypoechoic at baseline. Six developed hypoechogenicity over 2.5 years (eight tendons [9%], six participants [14%]), all in peri and post-PHV players. Twenty-six tendons (17 participants) were classified as immature during the study. Hypoechoic tendons were thicker (5.3 mm SD 1.2) than normal (3.9 mm SD 0.7) tendons (p < 0.001). There was no difference in the proportion of participants reporting pain during SLDS in the hypoechoic (N = 3) and normal (N = 11) groups (p = 0.33), or in hypoechoic tendon thickness between those reporting pain (6.5 mm, SD 1.7) or not (5.2 mm, SD 0.9, p = 0.17).
CONCLUSIONS: This study using grayscale ultrasound found that basketball players with hypoechogenicity were peri or post-PHV. Abnormal structure was not always associated with pain.

UNASSIGNED: In Professional Athletes, quadriceps and patellar tendon ruptures are devastating injuries, often resulting in the loss of a season or a decreased return to the pre-injury level of sport. This study aimed to perform a comprehensive Video Analysis on extensor mechanism rupture (EMR) to describe the body postures and related mechanism in Professional Athletes.
UNASSIGNED: Using publicly available data on quadriceps tendon and patellar tendon ruptures from between 2000 and 2020, 52 elite athletes were identified. Of these, twenty-eight injuries with adequate video data were analyzed for Injury Mechanism, body posture, as well as player and sports characteristics.
UNASSIGNED: Of the 27 athletes included in the study, with an average age of 28.18 ± 4.96 years, there were injuries in 28 extremities (1 case bilateral). The patellar tendon was ruptured in 20 cases (71.4%), and the quadriceps tendon in 8 cases (28.6%). There was total tendon rupture in 13 cases, and partial rupture in 6 cases (data for 1 case was not available). In 20 cases (70.4%), there was no contact resulting in the injury. Four of the contact injuries occurred in American football (3 direct, one indirect), 3 in basketball (1 direct, two indirect), and 1 in baseball (direct).
UNASSIGNED: The results of this research indicate that EMR occurs most commonly when the knee is in flexion and the ankle is in plantar flexion. There is the tendency for the knee to be in valgus at the time of injury. This information can guide physical therapy techniques, including neuromuscular training, proprioception, and balance training in the prevention of EMR in elite athletes.

Tendons play a crucial role in the musculoskeletal system. In humans, tendon injuries, especially chronic tendinopathy, are very common and the patellar tendon is a frequent location for tendinopathy or injuries. The biomechanical characteristics of the patellar tendon, such as elasticity and stiffness, are of paramount importance and constitute major outcome measures in research studies. We aimed to assess whether the stiffness of the healthy ovine patellar tendon changes with age and weight in a population of normal animals. Sixty-eight \'patella-patellar tendon-tibial tuberosity\' units from thirty-four Ile-de-France ewes of body mass 65 to 95 kg, euthanized for reasons other than musculoskeletal diseases, underwent a tensile test providing a measure of the tendon stiffness. Animals were sorted into three categories of age (1-2 yo, 3-5 yo, 6-10 yo). We found a positive but not significant correlation between age category and stiffness (r = 0.22, p = 0.27). There was a significantly positive correlation between weight and stiffness (r = 0.39, p = 0.04). In conclusion, the study characterized biomechanical properties of healthy tendons, provided useful reference values, and established the basis for future biomechanical tests on healing tendons in sheep. The most appropriate sheep population for those future studies would be non-overweight young adults presenting with no lameness.

The tip of the tibial tubercle (TTT) is used to assess tibial baseplate rotation in total knee arthroplasty (TKA); however, it can be difficult to palpate and visualize intraoperatively. Several more easily accessible soft-tissue structures have been proposed as intraoperative assessments, including the patellar tendon\'s medial border (MBPT) and the junction of the medial third of the patellar tendon (mt-PT). No studies have described the relationship between the TTT and these proposed landmarks. The aims of the study were to (1) determine the relationship of the soft-tissue landmarks to the TTT and (2) identify any sex differences in these measures. Measurements of the position of these soft-tissue landmarks relative to the TTT were made on 56 cadaveric knees (28 female) by two observers at the level of the standard tibial cut (10 mm distal to the lateral tibial plateau). The results obtained were compared by sex and side. On average, 50.7% (SD 6.79, range 33.1%-63.1%) of the patellar tendon footprint was medial to the TTT. There were no significant differences between the sexes or left and right lower limbs. However, there was large variability in the position of all the soft-tissue landmarks relative to the TTT. The results indicate that, on average, the patellar tendon footprint is evenly spread around the TTT. However, there is a large variability in the anatomical relationship between the soft-tissue landmarks and the TTT. Caution is advised if relying on these structures intraoperatively.

OBJECTIVE: The three most commonly used autografts for anterior cruciate ligament reconstruction (ACL) are: bone-patellar tendon-bone (BTB), hamstring tendons (HT), and quadriceps tendon (QT). A cadaveric study was performed to determine if there were any differences in mechanical and structural properties under biomechanical testing.
METHODS: Twenty-seven graft specimens were harvested from 9 human cadaveric legs. Mean donor age was 75.2 years (range 53-85 years). Twenty-two specimens (8 HT, 7 QT, and 7 BTB) completed cyclic preconditioning from 50 to 800 N for 200 cycles and a load to failure test at an extension rate of 1 mm/s. Structural and mechanical properties of BTB, HT, and QT grafts were compared using a one-way ANOVA and Tukey\'s honest significant difference.
RESULTS: There was no difference in the ultimate load to failure (N) across all 3 graft types (p = 0.951). Quadriceps tendon demonstrated greater cross-sectional area (mm2) when compared to both HT and BTB (p = 0.001) and was significantly stiffer (N/mm) than HT but not BTB (p = 0.004). Stress (N/mm2) of the HT at ultimate load was greater than QT but not BTB (p = 0.036). Elastic modulus (MPa) of HT was greater than both QT and BTB (p = 0.016).
CONCLUSIONS: There was no difference in the ultimate load to failure of BTB, HT, and QT grafts harvested from the same specimens. All 3 grafts had similar loads to failure with a significant increase in stiffness when compared to the native ACL. Furthermore, QT demonstrated more favourable structural properties compared to HT and BTB with greater cross-sectional area to both HT and BTB and greater stiffness compared to HT.

The objective of this study is to analyse differences in the thickness of the patellar (PT) and Achilles tendons (AT) among athletes with different number of meals per day. The design is a cross-sectional, observational study. A total of thirty-six male athletes (with mean age groups ranging from 31 to 40) were recruited and divided into three groups based on the number of daily meals they had (3, 4 or 5 meals). PT and AT were assessed by ultrasound. There were statistically significant differences in PT when comparing groups 1 and 3, at both longitudinal (p < 0.03) and transversal (p < 0.002) planes. There were no differences when comparing groups 1 and 2 or groups 2 and 3. There was a negative correlation between the number of meals per day and tendon thicknesses in both PT (longitudinal plane: r = -0.384; p = 0.02/transversal plane: r = -0.406; p = 0.01) and AT (transversal plane: r = -0.386; p = 0.02). In conclusion, there were patellar tendon thickness differences between participants and the number of daily meals could play a key role in tendon thickness, healing and performance.

OBJECTIVE: Morphometric analysis of the patella and the patellar ligament is crucial in diagnosing and surgical corrections of knee injuries and patellofemoral joint disorders. Dimensions of the patella and the patellar ligament are frequently used in implant design and ACL reconstruction. This study aims to obtain detailed morphometric data on the patellar ligament and its localization based on gross anatomical dissections in the adult cadavers.
METHODS: The present study consisted of 50 lower limbs from formalin-fixed male adult cadavers aged about 70 years (45-85) belonging to the South Indian population. Total length of the quadriceps tendon, patellar height, patellar ligament height, proximal width, distal width and thickness of the patellar ligament were measured meticulously. Mean, standard deviation, median scores of each parameter were computed for groups using SPSS 16.0. Level of significance was considered as p < 0.05. Wilcoxon signed-rank test was used to compare the various parameters on the right and left limbs. The relationships between all parameters were analyzed using Spearman\'s rank correlation test.
RESULTS: There was no statistically significant difference in the various measurements of the patella and patellar ligament between the right and left lower limbs. Patellar ligament length showed positive correlation with ligament thickness (r = 0.36; p = 0.078 for right limb and r = 0.33; p = 0.104 for left limb). Proximal width of ligament showed significant positive correlation with distal width (r = 0.41; p = 0.041 for right limb and r = 0.54; p = 0.006 for left limb).
CONCLUSIONS: This morphometric data and analysis might be fundamental in understanding various knee conditions in situ and necessary to orthopedic surgeons for successful planning and execution for ACL reconstruction using patellar ligament graft and other patellofemoral joint disorders.
METHODS: I.