OBJECTIVE: The aim is to assess performance characteristics in jumps and functionality in participants with patellar tendinopathy and compare changes with various tendinopathy treatments in the short and medium term. As a secondary objective, the study aims to verify the relationship between changes in knee functionality assessed by the VISA-P and jump capacity in the different treatment groups.
METHODS: A double-blinded randomized controlled trial.
METHODS: Recruitment was conducted at sport clubs, with 48 participants with patellar tendinopathy included in the study. Participants were randomized into groups: dry needling (DN), percutaneous electrolysis (PNE), and sham needling as the control group (CG), all combined with eccentric exercise (EE). Functionality and performance during jumps, including squat jump (SJ) and counter movement jump (CMJ), were assessed.
RESULTS: Significant differences were found in functionality between the pre-test and post-test evaluations, as well as between the pre-test and follow-up evaluations, in all three groups (p < 0.001). The DN group experienced an improvement in eccentric power (p = 0.021). A moderate correlation was found between the pre-test and post-test changes in functionality and SJ maximum concentric force (r = 0.63, p < 0.01, CI: 0.1; 0.8), CMJ maximum concentric force (r = 0.52, p = 0.05, CI: -0.01; 0.8), and CMJ eccentric power in the DN group (r = 0.63, p = 0.01, CI: 0.1; 0.8).
CONCLUSIONS: Eccentric exercise could be effective in improving functionality in patellar tendinopathy and DN could improve eccentric power in jumps performance. Moreover, the DN group experienced an increase in functionality that correlated with the improvements found in jump performance in eccentric power and concentric strength.

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.

Graft failure is a common postoperative complication after anterior cruciate ligament (ACL) reconstruction. Recently, a theory has emerged that histological and microstructural factors of autografts may be related to graft failure. We simultaneously collected the semitendinosus tendon (ST), quadriceps tendon (QT), and patellar tendon (PT) from a 22-year-old patient to provide insights into the differences in the collagen-type composition of the three tendons in skeletally mature patients. These findings may serve as a basis for selecting autografts for ACL to reduce graft failure rates. The patient was a 22-year-old female who required the removal of artificial ligament, screws, and washers and medial patellofemoral ligament (MPFL) reconstruction with an ST autograft after two surgeries for recurrent dislocation of the left patella. The ST, QT, and PT obtained during necessary intraoperative procedures were used as samples. The tissues were processed and immunostained; this was followed by confocal microscopy. Evaluation was performed by calculating the percentage of areas positive for collagen types I and III.The percentage of type I collagen in the ST, QT, and PT groups was 88%, 85%, and 88%, respectively.The collagen-type composition was examined following simultaneous collection of the ST, QT, and PT. The results revealed no significant differences in the content of physically strong type I collagen, which supports previous findings showing that the clinical outcomes after ACL reconstruction do not vary with the autograft used.

UNASSIGNED: The extensor mechanism and patellar tendon (PT) are considered essential components. Adult PT avulsion from the tibial tubercle is uncommon, with little information in the literature. Technical challenges arise during injury management. Knotless anchors have several applications in treating tendon injuries, such as the rotator cuff, distal biceps, and quadriceps tendons but were not used to repair distal PT avulsions.
UNASSIGNED: A 50-year-old male patient, an active adult, presented to emergency department with significant right knee pain, giving away and limitation of range of motion (ROM) that had started after he sustained direct trauma with a ground-level fall on his knee that morning.
UNASSIGNED: In this paper, we report a case and describe a technique to manage a rare presentation of pure distal PT rupture without an avulsion fracture using knotless anchors with FiberTape®, which showed excellent results. To the best of our knowledge, this technique has never been used before in such injury and anatomical location. At 2 years of follow-up, the patient is free of complaints with almost full ROM at the knee and back to his standard daily life activity.

BACKGROUND: Pain provocation tests are recommended for assessing pain severity and as an outcome measure for individuals with patellar tendinopathy.
OBJECTIVE: To evaluate floor and ceiling effects, sensitivity to change, and responsiveness cut-offs of two provocative load tests among athletes with patellar tendinopathy.
METHODS: Athletes (N = 41) performed six repetitions for the single leg decline squat (SLDS) and resisted knee extension (KE) at baseline and 12 weeks. Participants rated their pain during each test on a visual analog scale (VAS). Sensitivity to change was assessed by calculating effect size (ES) and the standardized response mean (SRM). The responsiveness cut-offs were assessed using a combination of anchor and distribution- based methods to determine the minimal clinically important difference (MCID) for each test.
RESULTS: A floor or ceiling effect was observed in only a small number of participants for both tests except for KE, for which approximately one third of participants had a floor effect at week 12. There was higher sensitivity to change for SLDS (ES: 1.93/SRM: 1.43) compared with KE (ES:0.96/SRM: 1.09). The MCID corresponded to a decrease of 1.6 points for SLDS and 1.0 for KE, while the distribution-based method estimated 1.2 points for SLDS and 1.1 for KE.
CONCLUSIONS: This study found moderate to high sensitivity to change and established MCID values for the SLDS and KE test in athletes with patellar tendinopathy before and after rehabilitation. Both tests may be useful as pain on loading outcomes as athletes progress with their rehabilitation, but the KE test results in higher floor effects and has lower sensitivity to change.

Background: The treatment of patellar tendon injury has always been an unsolved problem, and mechanical characterization is very important for its repair and reconstruction. Elastin is a contributor to mechanics, but it is not clear how it affects the elasticity, viscoelastic properties, and structure of patellar tendon. Methods: The patellar tendons from six fresh adult experimental pigs were used in this study and they were made into 77 samples. The patellar tendon was specifically degraded by elastase, and the regional mechanical response and structural changes were investigated by: (1) Based on the previous study of elastase treatment conditions, the biochemical quantification of collagen, glycosaminoglycan and total protein was carried out; (2) The patellar tendon was divided into the proximal, central, and distal regions, and then the axial tensile test and stress relaxation test were performed before and after phosphate-buffered saline (PBS) or elastase treatment; (3) The dynamic constitutive model was established by the obtained mechanical data; (4) The structural relationship between elastin and collagen fibers was analyzed by two-photon microscopy and histology. Results: There was no statistical difference in mechanics between patellar tendon regions. Compared with those before elastase treatment, the low tensile modulus decreased by 75%-80%, the high tensile modulus decreased by 38%-47%, and the transition strain was prolonged after treatment. For viscoelastic behavior, the stress relaxation increased, the initial slope increased by 55%, the saturation slope increased by 44%, and the transition time increased by 25% after enzyme treatment. Elastin degradation made the collagen fibers of patellar tendon become disordered and looser, and the fiber wavelength increased significantly. Conclusion: The results of this study show that elastin plays an important role in the mechanical properties and fiber structure stability of patellar tendon, which supplements the structure-function relationship information of patellar tendon. The established constitutive model is of great significance to the prediction, repair and replacement of patellar tendon injury. In addition, human patellar tendon has a higher elastin content, so the results of this study can provide supporting information on the natural properties of tendon elastin degradation and guide the development of artificial patellar tendon biomaterials.

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The aim of this study was to investigate the effect of aging and resistance training with a moderate load on the size and mechanical properties of the patellar (PT) and Achilles tendon (AT) and their associated aponeuroses; medial gastrocnemius (MG) and vastus lateralis (VL). Young (Y55; 24.8 ± 3.8 yrs, n = 11) and old men (O55; 70.0 ± 4.6 yrs, n = 13) were assigned to undergo a training program (12 weeks; 3 times/week) of moderate slow resistance training [55% of one repetition maximum (RM)] of the triceps surae and quadriceps muscles. Tendon dimensions were assessed using 1.5 T magnetic resonance imaging before and after 12 weeks. AT and PT cross sectional area (CSA) were determined every 10% of tendon length. Mechanical properties of the free AT, MG aponeurosis, PT, and VL aponeurosis were assessed using ultrasonography (deformation) and tendon force measurements. CSA of the AT but not PT was greater in O55 compared with Y55. At baseline, mechanical properties were generally lower in O55 than Y55 for AT, MG aponeurosis and VL aponeurosis (Young\'s modulus) but not for PT. CSA of the AT and PT increased equally in both groups following training. Further, for a given force, stiffness and Young\'s modulus also increased equally for VL aponeurosis and AT, for boths groups. The present study highlights that except for the PT, older men have lower tendon (AT, MG aponeurosis, and VL aponeurosis) mechanical properties than young men and 12-weeks of moderate slow resistance training appears sufficient to improve tendon size and mechanical adaptations in both young and older men. New and Noteworthy: These novel findings suggest that short-term moderate slow resistance training induces equal improvements in tendon size and mechanics regardless of age.

The surgical treatment of anterior cruciate ligament (ACL) injuries dates back over 100 years from the present day [2022]. While open repair of the torn ACL was popularized in the early 1900s, the first ACL reconstructions utilized the fascia lata as a graft and other extra-articular stabilizing techniques. The first free tendon graft reported for ACL reconstructions was the quadriceps tendon (QT) in the 1930s, followed by the hamstrings tendon (HT), and then the patellar tendon. With improved understanding of the ACL anatomy and biomechanics and the invention of the arthroscope, ACL reconstruction evolved from open procedures to arthroscopic. Similarly, with the help of many surgeon-scientists who reported patient outcomes following ACL reconstruction with various techniques, graft choice evolved with the hamstrings and patellar tendon grafts becoming the dominant and preferred choice of both surgeons and patients. In present day, we see a resurgence of one of the original grafts reported, the QT, as well as primary ACL repair. Future research will result in continued advancements of ACL surgical techniques and graft harvesting, which will allow the orthopedic community (including patients and surgeons) to benefit from such innovations and advanced technologies.