Objective This finite element study aimed to biomechanically compare screw fixation vs. K-wire fixation for adolescent tibial tubercle avulsion fractures (TTAF), investigating the differential biomechanical outcomes and physeal insult associated with each fixation method. Methods A finite element model of an adolescent tibia with a Modified Ogden type III fracture was developed. Three fixation types—(A) screws, (B) two non-crossing K-wires, and (C) four crossing K-wires—were tested both as standalone constructs and in their tension band-augmented counterparts. Simulations applied a 1,654 N tensile load to simulate patellar tendon force, with outcomes assessed by fragment displacement, bone and epiphyseal von Mises stress. Results Screw fixation (Type C3) demonstrated the highest stability, with fragment displacement of 1.97 mm and the lowest bone stress (295.79 MPa). K-wire constructs showed greater displacement and stress. The addition of a third fixator provided minimal stability improvement compared to two. Tension bands increased stability in K-wire models but raised bone stress to approximately 1,100 MPa and increased physeal stress. Conclusion Biomechanical analysis of TTAF reveals that screw fixation provides enhanced stability and reduced bone stress compared to K-wire fixation. Furthermore, the stability achieved with dual screws is comparable to that of triple screws, implying that adding more implants offers a limited advantage in fracture fixation stability. Considering the greatest physeal insult, particularly in skeletally immature individuals with retained growth potential, tension band wiring should be used sparingly. Based on these results, screw fixation is recommended as the optimal approach for adolescent TTAF.

Mapping tendon stiffness: Two-dimensional versus point shear wave elastography.

Prolonged passive vibration of Achilles and patellar tendons decreases effort perception during subsequent cycling tasks.

The infrapatellar fat pad (IPFP), or Hoffa fat pad, is frequently resected during total knee arthroplasty (TKA) to improve surgical exposure. However, its removal may affect patellar tendon integrity, vascular supply, and long-term functional outcomes. The role of the IPFP in osteoarthritis and its contribution to anterior knee pain remain topics of debate. To compare radiological and functional outcomes of patients undergoing TKA with either preservation or complete resection of the IPFP. This retrospective, observational study was conducted at a single institution between 2018 and 2021. Patients undergoing primary TKA for idiopathic osteoarthritis were divided into 2 groups according to the operating surgeon’s routine practice: IPFP preserved or IPFP resected. The primary outcomes were Insall–Salvati ratio, Oxford Knee Score, and Visual Analog Scale for anterior knee pain. Radiological and clinical evaluations were performed at 6 and 12 weeks, and annually up to 3 years postoperatively. At final follow-up, baseline demographics were comparable between groups. Postoperative Insall–Salvati ratio was 1.077 ± 0.12 in the excision group and 1.076 ± 0.12 in the preservation group (P = .93). Knee flexion improved similarly (115.8 ± 10.2° vs 116.0 ± 10.5°, P = .86). At 3 years, mean Oxford Knee Score was 20.3 ± 5.1 in the excision group and 19.9 ± 5.4 in the preservation group (P = .45), while mean Visual Analog Scale for anterior knee pain was 3.27 ± 0.4 versus 3.17 ± 0.4 (P = .064). Surgical time was shorter in the excision group (88 ± 8 vs 90 ± 6 minutes, P = .022); however, this small difference is unlikely to be clinically meaningful. Both groups demonstrated significant improvement in functional outcomes from baseline, with no long-term superiority of either approach. IPFP management during TKA does not significantly influence mid-term radiological or functional outcomes. Preservation may help maintain tendon integrity, whereas excision may modestly reduce operative time without affecting long-term patient-reported results. The choice to resect or preserve should therefore be based on intraoperative exposure and surgeon preference rather than expectations of improved outcomes.

Patellar Tendon Z-plasty Approach for Comminuted Tibial Plateau Fractures

Objectives: The role of internal bracing in lower limb tendon repairs and reconstructions is not widely published. We report our techniques for internal brace-augmented tendon repair (IBA-TR) in the surgical treatment of acute ruptures of the patellar tendon, the quadriceps tendon and the Achilles tendon. Methods: The outcomes of 100 cases of IBA-TR treated by a single surgeon over an 8-year period (2014–2022) were retrospectively analysed with a minimum follow-up of 6 months. Results: The mean time to mobilisation without a brace was 32 days. Three cases of infection were reported and treated with antibiotics, with no cases of deep infection requiring return to theatre. There were no cases of venous thromboembolism. No cases of failure of tendon repair were observed. Of the 100 patients, 98 returned to their pre-injury level of activity. Conclusions: This study represents the largest cohort of tendon repairs augmented with an internal brace to date. With no reported failures or returns to theatre, this repair technique has been demonstrated to be safe and clinically effective, dispensing with the need for cast immobilisation. Level of evidence: III.

The study analysed unique data on anterior cruciate ligament (ACL) injuries among German professional female and male team sports over seven consecutive seasons with the aim of identifying sex specific differences regarding ACL injury risk, burden and treatment strategies. This prospective observational open cohort study analysed unique insurance data on all complete ACL ruptures from female and male players with at least one competitive match appearance in the two highest divisions of German professional football. The long-term study covered seven consecutive seasons between 2014/15 and 2020/21 and included complete ACL ruptures registered by clubs or physicians with the German statutory accidental insurance for professional athletes (VBG) as part of occupational accident reporting. In total, 131 out of 2965 female players (4.4%) and 95 out of 2639 male players (3.6%) sustained an ACL injury. Mean ACL injury prevalence in female football was 3.0% (95% confidence interval [CI] 1.8-4.3) with an increasing trend over time. Mean ACL injury prevalence in men's professional football was 1.6% (95% CI 0.8-2.3). The overall match incidence in female players was 0.91 ACL injuries per 1000 h of match exposure (95% CI 0.72-1.11). The overall match incidence in male football was 2.5-fold smaller (0.37 ACL injuries per 1000 h of match exposure (95% CI 0.28-0.47). Almost all ACL injuries (99.2%) were treated surgically. Patellar tendon grafts were used more often in male players compared to female players (p < 0.001). The mean period between the day of an ACL injury and the day of surgery was significant longer in female (median 19 days [interquartile range {IQR} 22]) than in male players (median 6 days (IQR 8, p < 0.001). Overall, female players had significant longer time loss after ACL injury and after ACLR compared to men (p < 0.001). The total secondary ACL injury rate after RTP was 31.7% for female players and 32.1% for male players. Female players were significantly younger at their retirement compared to males (26.7 ± 4.2 vs. 33.5 ± 3.3, p < 0.001). The ACL prevalence and match injury risk is higher in female players compared with males. Moreover, the present study shows an increasing trend for both parameters in German female professional football. One out of three players, irrespective of sex, sustained a second ACL injury over a median follow-up of six years. However, women end their careers earlier than men after an ACL injury, which could understate the actual extent of the second ACL injury rate in women. While sex-specific care would be advisable, access to medical treatment still seems to be limited in women's football. Therefore, the therapeutic and medical framework conditions in women's football should be aligned first. Level II.

We investigated the effects of 8-weeks of eccentric resistance exercise (RE) with hydrolyzed collagen supplementation on patellar tendon (PT) cross-sectional area (CSA), vastus lateralis (VL)muscle size, maximum voluntary force (MVF), and peak rate of force development (pRFD) in international female field hockey Master athletes. Twenty-two premenopausal women (37 ± 2years, 68.9 ± 8.0kg, and 1.68 ± 0.04m) were randomly assigned to collagen (COL; n = 10) and placebo (PLA; n = 12) cohorts in a triple-blind design. They completed three eccentric RE sessions per week for 8weeks in addition to their regular hockey training. Before each RE session, participants ingested 30g hydrolyzed COL or 32.9g maltodextrin (PLA), together with 500mg vitamin C. Pre- and postintervention, we assessed MVF and pRFD during a voluntary multijoint isometric muscle contraction and countermovement jump height, and VL thickness and PT CSA were measured with ultrasonography. MVF increased from 892 ± 366 to 1,011 ± 420N (p = .020) and VL thickness increased from 21 ± 3 to 22 ± 3mm (p = .015), with no Group × Time interactions (p > .05), whereas countermovement jump height did not change (p = .238). PT CSA increased in both groups (p < .001) but more in COL (116 ± 12 to 121 ± 13mm2) than PLA (109 ± 22 to 111 ± 22mm2, p = .014). Similarly, pRFD increased in both groups (p = .002) but more in COL (7.9 ± 1.3 to 10.1 ± 2.4kN/s) than PLA (8.2 ± 2.4 to 9.6 ± 2.9kN/s, p = .039). Therefore, hydrolyzed collagen supplementation enhanced gains in PT CSA and pRFD following 8weeks of eccentric RE in elite female field hockey Master athletes, thus providing an effective strategy to improve physical performance in this underresearched population.

Anatomical reconstruction of the patellar tendon with coverage using a perforator LGAP flap in ballistic trauma: The importance of interdisciplinary collaboration.

Predicting spontaneous tendon rupture in dialysis: a parsimonious clinical model on the frailty and CKD-MBD axis.

MRI manifestations and associated injuries in adolescent tibial tuberosity fractures: A retrospective study.

Short-term results of metaphyseal sleeves in total knee arthroplasty for severe bone defects of the tibia.

Background:The management of revision anterior cruciate ligament reconstruction (ACLR) presents unique challenges that require careful consideration of graft selection and the role of anterolateral complex (ALC) augmentation. Although surgical techniques continue to evolve, there is variability in clinical practice patterns for revision ACLR.Purpose:To assess current trends in revision ACLR, including ALC augmentation indications, preferred augmentation techniques, and choice of graft type.Study Design:Cross-sectional study; Level of evidence, 3.Methods:A survey was distributed by email to all members of the American Orthopaedic Society for Sports Medicine (AOSSM). The survey included a demographics section (5 questions) and a revision ACLR section (12 questions). Descriptive statistics were performed.Results:There were 469 responses (response rate, 14%), with respondents more commonly being male (90%), fellowship-trained (95%), and in private practice (42%). The revision ACLR volume rose with the number of years in practice (P = .008). The autograft patellar tendon (47%) was the most frequently selected revision graft, followed by the quadriceps tendon (22%). The graft choice was associated with fellowship training (P = .006), years of experience (P < .001), and type of practice (P = .015). ALC augmentation was used by 70% of respondents, mostly for multiple (52%) or single (37%) previous ACLR failures and contact athlete status (17%). Its use was more common among early-career (88%; P = .006) and academic (87%; P < .001) surgeons. Practice setting correlated with the choice between lateral extra-articular tenodesis (LET) and anterolateral ligament reconstruction (ALL) (P = .03), with academic surgeons utilizing LET at the highest rate. ALL was favored in patients with a body mass index of >35 kg/m2 (P = .003) and LET in contact sport athletes (P = .006). Altogether, 80% of the surgeons preferred LET over ALL as their primary choice for augmentation.Conclusion:Revision ACLR practices vary widely, with no uniform consensus on graft choice and indications for ALC augmentation. ALC augmentation is most frequently indicated for patients with multiple previous failures. LET is the preferred augmentation technique, and the autograft patellar tendon is the most utilized graft in revision ACLR. Long-term outcomes of revision ACLR should be further studied to define ideal indications for augmentation and graft selection to address the relatively poor outcomes observed in patients undergoing revision ACLR.

Preoperative stiffness in the knee joint significantly compromises outcomes after total knee arthroplasty (TKA). Robotic-assisted TKA (raTKA) using the imageless CORI system may offer precision in alignment and gap balancing, especially in difficult cases with limited range of motion (ROM). We present a case series of 25 knees in 22 patients with preoperative ROM < 50°, all treated using the imageless CORI robotic system (Smith & Nephew). All patients had advanced osteoarthritis or inflammatory arthritis and underwent primary TKA through a standard medial parapatellar approach with posterior cruciate-sacrificing implants. Postoperative follow-ups were conducted at 15days, 3months, 6months, 1year, and 2years, with evaluation of ROM, Knee Society Score (KSS), and Visual Analog Score (VAS). Mean preoperative ROM was 38.7° ± 5.4 (range: 28°-45°). At final follow-up, all patients showed significant improvement in ROM, with a mean of 110.2° ± 6.2. KSS improved from a mean of 32 to 84, and VAS decreased from a mean of 8.2 to 1.6. Varus deformity was corrected in all patients. No cases of postoperative neurovascular complications, patellar tendon injuries, or manipulations under anesthesia were noted. The CORI robotic system offers a promising strategy for managing preoperatively stiff knees. It allows precise bone cuts and real-time soft tissue balancing with minimal releases, reducing complications, and improving functional outcomes. Further controlled studies are needed to establish its long-term advantages.

ABSTRACTTendon structural and mechanical integrity is essential for overall joint function. Establishment of tendon structure–function is regulated by coordinated processes between cells and the extracellular matrix. However, the cell–cell and cell–matrix interactions necessary for re‐creating the native tendon structure following injury remain unelucidated. Collagen XII is a fibril‐associated collagen with key structural roles in modulating collagen fibrillogenesis, matrix protein interactions, and forming bridges between fibrils. Collagen XII has also been shown to regulate cell structure and organization, suggesting that collagen XII coordinates cell‐ and matrix‐mediated processes necessary for proper tendon formation. Therefore, the study objective was to define the temporal roles of collagen XII in regulating cell arrangement and matrix assembly during tendon development. To investigate the cumulative effects of manipulating collagen XII expression in tendon with respect to cell organization, scleraxis‐Cre collagen XII knockout mice were evaluated for patellar tendon morphology, cell organization, matrix structure and function, and gene expression. At postnatal day 0, disruptions to cell and matrix organization due to collagen XII knockout were profound. F‐actin organization in knockout tendons lacked parallelism with areas of high density, and cell membrane protrusions did not make contact with neighboring cells. Disrupted matrix structure was also observed at later postnatal ages, indicating a critical cell‐mediated role of collagen XII. Collagen XII knockout also inhibited the formation of a proper tibial attachment, resulting in altered collagen organization and mechanical properties at the insertion site. To investigate the specific matrix assembly role of collagen XII, knockdown was induced at postnatal day 0. Mechanical changes at the tibial insertion site were similar, but overall effects on matrix organization and structure were minimal. Together, our findings indicate a more substantial role of collagen XII for regulating cell arrangement rather than matrix assembly in the establishment of tendon structure–function.

The objective of this study was to compare the ultimate tissue strength of the rectus femoris (RF) and patellar tendons using paired soft-tissue grafts obtained from fresh organ donors, simulating clinical graft preparation. Fourteen paired RF and patellar tendon (PT) grafts were harvested from seven organ donors and tested within 12 h postmortem. The RF was folded and mounted as a double-stranded graft to simulate its clinical use. All grafts underwent uniaxial tensile testing using a standardised protocol. Primary outcomes included ultimate stress (MPa), load to failure (N) and elongation at failure (%). Data distribution was assessed with the Shapiro-Wilk test, and paired t-tests or Wilcoxon signed-rank tests were applied accordingly. A post hoc power analysis was conducted to determine the minimum detectable difference in stress with the given sample size. Ultimate stress did not differ significantly between RF and PT grafts (46.4 ± 10.5 MPa vs. 52.9 ± 9.7 MPa, p = 0.184). RF grafts showed significantly lower load to failure (885.9 ± 52.3 N vs. 1278.7 ± 207.5 N, p < 0.001) and greater elongation (1.2 ± 0.2% vs. 0.2 ± 0.1%, p < 0.001). This study found that the double-stranded RF tendon exhibits ultimate tissue strength comparable to the patellar tendon, despite differences in load to failure and elongation. These results highlight the RF as a biomechanically viable graft option that merits further investigation. Given its consistent dimensions and soft-tissue-only harvest, the RF tendon represents a reproducible and potentially less invasive alternative for knee ligament reconstruction. N/A.

Tendinopathy is a complex, painful condition that affects up to 5% of the general population in their lifetime. Antibiotic treatment with fluoroquinolones has been associated with the onset of tendinopathy and tendon rupture. The mechanisms behind fluoroquinolone induced tendinopathy remain unclear. To probe activation of potentially causative pathways, we treated juvenile mice with ciprofloxacin in drinking water for 4 weeks and performed RNA sequencing on tail tendons. We discovered that ciprofloxacin-treated mice had upregulated genes relating to nerve development. Additionally, treated mice showed downregulation of genes associated with extracellular matrix (ECM) processes. We further explored ECM changes using histological and mechanical testing methods on patellar tendons. We found that ciprofloxacin treatment led to altered cell morphology and proteoglycan density. These changes translated to a decrease in mechanical properties of the patellar tendons. Furthermore, ciprofloxacin-treated mice had a higher percentage of apoptotic cells, and we confirmed increased presence of nerve cells (Plexin B1+) in the patellar tendons compared to controls. Taken together, we showed that ciprofloxacin treatment in juvenile mice induces structural and biological phenotypes commonly associated with fluoroquinolone-induced tendinopathy and identify the axis of pathological neural activation as a promising area for further exploration. Clinical significance: Oral administration of ciprofloxacin in mice presents a clinically relevant model for studying mechanisms of tendinopathy in humans.

Background: Approximately 55% of individuals return to previous sports levels after anterior cruciate ligament (ACL) reconstruction (ACLR), but the duration of their sporting life post-ACLR and how this differs from uninjured sports participants is unknown. Purpose: To trace the 25-year trajectory of sports participation in individuals who have undergone ACLR and compare sporting activity between graft types and between ACLR individuals and uninjured controls. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 62 individuals (44 males; mean age, 27 years) underwent ACLR (31 bone–patellar tendon–bone grafting, 31 semitendinosus/gracilis grafting). Sporting activity was assessed preinjury, at 6 and 25 years after surgery on a 6-point scale based on pivoting demands. A total of 30 uninjured individuals matched for age, sex, and sporting activity were assessed at equivalent time points. Pearson chi-square and Student t tests were used to compare outcomes between graft types and between ACLR individuals and controls. Results: In total, 50 (81%) individuals (35 males) with ACLR and 20 (67%) uninjured controls were followed up after 25 years. Overall, 88% of the ACLR group were active in sports, 22% in vigorous pivoting sports. Three ACLR individuals had total knee replacements, 9 ruptured their contralateral ACL, and 8 ruptured their graft. There was no significant difference between graft types in sports level played presurgery (P = .442), 6 years after surgery (P = .511), or 25 years after surgery (P = .100). At 25 years after surgery, ACLR individuals participated in sports at higher levels (P = .005) and over longer periods (P = .032) than controls. Conclusion: Interestingly, after ACLR, patients were more engaged in sports than uninjured controls. Although the level of sports activity typically decreased over 25 years, findings highlight the potential for longevity in sports after an ACLR, irrespective of graft type.

Background:The optimal graft choice and fixation technique remain a topic of ongoing debate in both primary and revision anterior cruciate ligament (ACL) reconstruction (ACLR). Cortical tibial press-fit fixation offers known advantages such as eliminating the need for hardware, thereby reducing cost and avoiding complications related to implants, while also potentially minimizing bone tunnel enlargement.Purpose:To investigate the time-zero biomechanical properties (cyclic displacement, stiffness, and load to failure) of cortical tibial press-fit technique using bone–patellar tendon (BPT) graft for ACLR and compare with metal interference screw fixation to determine the potential clinical benefit of this technique.Study Design:Controlled laboratory study.Methods:A total of 24 skeletally mature porcine knees were used. After determining the bone mineral density (BMD) of each specimen, the specimens were randomly assigned to their respective groups. One group underwent interference screw (9 mm–diameter × 25 mm–length) fixation using a BPT autograft, while the other group underwent implant-free cortical tibial press-fit fixation. Biomechanical testing included 3 loading phases: (1) preconditioning (10-50 N for 10 cycles); (2) submaximal cyclic loading (50-200 N for 1500 cycles); and (3) load to failure testing at a 20 mm/min loading rate. Groups were compared for stiffness, cyclic displacement and ultimate load to failure using Mann-Whitney U tests and for failure mode using a Fisher exact test.Results:Both groups of specimens showed similar BMD characteristics (P = .59). There was no significant difference in cyclic displacement (interference screw group, 5.73 ± 1.71 mm; press-fit group, 5.03 ± 1.70 mm; P = .38), or total displacement (interference screw group, 11.02 ± 3.37 mm; press-fit group, 10.33 ± 3.70 mm; P = .76). The mean cyclic displacement of the bone plugs was not significantly different between groups (interference screw group, 0.06 ± 0.05 mm; press-fit group, 0.03 ± 0.05 mm; P = .19). Stiffness at the last submaximal loading cycle was comparable between the groups (interference screw group, 65.32 ± 11.16 N/mm; press-fit group, 70.27 ± 13.39 N/mm; P = .76). Mean ultimate load at failure was 586.4 ± 75.9 N (range, 467.9-745.9 N) for the interference screw fixation group and 639.0 ± 149.2 N (range, 485.1-1050.5 N) for the press-fit group and (P = .51). All specimens failed due to tendon avulsion at the tendon-bone junction or tendon rupture at the midsubstance.Conclusion:In this porcine patellar tendon ACLR tibial fixation model, cortical tibial press-fit fixation provided adequate primary stability, demonstrating similar cyclic displacement, construct stiffness, and ultimate load characteristics compared with interference screw fixation.Clinical Relevance:Cortical tibial press-fit technique may represent an effective method for ACLR.

Tendon injury is one of the most frequently encountered soft tissue injuries with slow repair and poor functional recovery. Over the past few years, there’s been a buzz about how exosomes might boost tissue repair and regeneration. This research dive delves into the question of whether Schwann cell-derived exosomes (SCDEs) can jumpstart tendon healing by tweaking the PTEN/PI3K/Akt signaling chain.been concentrated on the effects of exosomes in promoting tissue regeneration and repair. In the present study, we would like to explore whether exosomes derived from Schwann cells (SCDE) could promote tendon repair via modulation of PTEN/PI3K/Akt signaling cascade. This study integrates experiments performed both in vitro and in vivo. Tendon cells were categorized into the NC and SCDE groups, with a scratch assay employed.vitro and in vivo conditions tendo cells were divided into the NC group and SCDE group, and scratch assay, Transwell migration assay, flow cytometry for cell cycle detection, and Western blot and qRT-PCR analyses were performed to measure SCX, DCN, COL1A1, p-AKT, PTEN, and other markers.In the in vivo experiments, a rat model of 1/3 patellar tendon defect was established, and hydrogel or hydrogel + SCDE was injected. Tissues were gathered at 2, 4, and 8 weeks following the surgical procedure, and HE, Masson, and Sirius Red stains were applied to gauge the healing process. Important protein levels were assessed at the 2 week mark after the operation.Masson, and Sirius Red staining were performed to evaluate tissue repair. Key protein expression was measured at 2 weeks post-surgery.