Preoperative MRI-Based Assessment of the Quadriceps Tendon Autograft and Its Implications for Patient-Personalized Approaches in Anterior Cruciate Ligament Reconstruction

This study aimed to clarify the clinical relevance of quadriceps tendon alignment (QTA), focusing on the quadriceps tendon axial angle (QTAx), in patients undergoing 'physiological total knee arthroplasty (TKA)'. This concept combines unrestricted kinematic alignment (KA) with a medial pivot implant to alter as little as possible the individual knee anatomy and kinematics. It was hypothesised that QTAx would not significantly influence patient-reported outcomes. A retrospective cohort analysis was performed on 54 knees in 50 patients who underwent physiological TKA performed with a non-KA-optimised implant design and without patella resurfacing between September 2022 and April 2024. Patient-reported outcomes, including the Oxford knee score, forgotten joint score, patient's joint perception, pain visual analogue scale and satisfaction visual analogue scale, were evaluated before surgery and at 1 year postoperatively. QTAx was measured on preoperative computed tomography scans. Patients were categorised into three groups according to their QTAx angle: low (<mean -1 SD), middle (within mean ±1 SD) and high (>mean +1 SD). Significant improvements were observed in all patient-reported outcomes 1 year after surgery. QTAx demonstrated no significant correlation with any outcome. Clinical results did not differ significantly among the three QTAx alignment groups, although the high-angle group tended to show slightly better outcomes. Two patients (3.7%) underwent secondary patellar resurfacing for persistent anterior knee pain. This study found that variation in QTA, as assessed by QTAx, was not significantly associated with 1-year clinical outcomes following physiological TKA performed with a non-KA-optimised implant and without patellar resurfacing. Our findings suggest that specific surgical techniques to counteract high QTA may not be necessary within the context of physiological TKA. Level III.

Quadriceps tendon (QT) autografts are increasingly used worldwide in anterior cruciate ligament (ACL) reconstruction (ACLR). However, comparative outcome studies across graft types, particularly by sex, remain limited. To compare patient-reported outcomes (PROs) and revision rates after primary ACLR with QT autografts in relation to patellar tendon (PT) and hamstring tendon (HT) autografts, stratified by sex. Cohort study; Level of evidence, 3. Patients who underwent primary ACLR (2008-2022) were identified in the Swedish Knee Ligament Registry. The primary outcome was 2-year patient-reported knee function, assessed using the Knee injury and Osteoarthritis Outcome Score (KOOS). Clinical relevance was evaluated using the KOOS4 (mean of KOOS Pain, Symptoms, Sports/Recreation, and Quality of Life subscales), with thresholds for minimal important change (MIC, ≥9), patient acceptable symptom state (PASS, ≥79), and treatment failure (TF, ≤42). Adjusted logistic regression analyses assessed factors associated with MIC, PASS, and TF. The secondary outcome was 2-year revision ACLR, reported as rates and analyzed using Cox regression to estimate hazard ratios. A total of 18,920 patients (44%) had 2-year KOOS data available. Women receiving QT grafts had a lower proportion of MICs achieved than those with HT grafts (61% vs 71%; P = .027). Among men, PASS was more frequently achieved with QT (51%) and HT grafts (48%) than with PT grafts (40%) (both P≤ .030). In the regression analyses, women with HT grafts had higher odds of achieving MIC (odds ratio [OR], 1.69 [95% CI, 1.19-2.42]; P = .004) and PASS (OR, 1.81 [95% CI, 1.28-2.58]; P < .001), and lower odds of TF (OR, 0.53 [95% CI, 0.31-0.88]; P = .015) compared with QT grafts. Additionally, no significant differences were observed between QT and PT grafts in women or among graft types in men.Of 44,513 patients, 1019 (2.3%) underwent revision ACLR within 2 years: QT graft, 2.2% (28/1274); PT graft, 2.5% (50/2019); and HT graft, 2.3% (941/41,220) (P = .830). QT revision rates were 2.7% in women and 1.8% in men (P = .288). Graft type was not associated with revision hazard in adjusted Cox regression. QT autografts were associated with lower PROs compared with HT autografts in women, whereas no such differences were observed when compared with PT autografts or among men. Revision rates were similar across graft types, both overall and by sex.

Anterior cruciate ligament reconstruction (ACLR) is a known risk factor for ipsilateral and contralateral anterior cruciate ligament (ACL) tear, influenced by patient age, activity level, and graft choice. The Multicenter Orthopaedic Outcome Network (MOON) calculator predicts risks post-ACLR, aiding in graft selection and prognosis. The MOON calculator is only validated for those patients under 22 years of age and with patellar bone-tendon-bone (BTB) or hamstring tendon graft options, restricting its applicability. This study assessed the MOON calculator's accuracy in a more diverse patient population, including quadriceps tendon (QT) recipients and patients > 22. With institutional review board approval, registry data were reviewed for patients with primary ACLR at our institution over the past 10 years. Patient information was entered into the MOON calculator, adjusting ages over the calculator's maximum to "22 years" for entry. Patients with QT grafts were entered as BTB. MOON retear and contralateral tear risk predictions were recorded. True outcomes were extracted from medical records. A Brier score of <0.25 was chosen a priori as indicative of acceptable model calibration. An area under the curve (AUC) threshold of 0.70 was determined to indicate acceptable discrimination. A total of 78 patients (49 ≤22 years, 29 23+ years), fulfilled inclusion criteria for analyses. A total of 64 patients received QT grafts (82.1%) and 14 received BTB (17.9%). There were three ACL retears, two QT (3.1%), and one BTB (7.1%) patients. MOON predicted a retear rate of 8.3% for the combined BTB + QT graft group. Brier and receiver operating characteristic curve results suggest poor model calibration, but good discrimination-QT Brier score: 0.89, AUC 0.782, and BTB Brier score: 0.84, AUC 0.846. Analysis restricted to those >22years-QT Brier: 0.84, AUC 0.525, showed poor accuracy and poor outcome discrimination. BTB Brier score: 0.81, AUC 0.778, demonstrated acceptable discrimination. The MOON calculator was not effective in predicting ipsilateral ACL retear risk with the inclusion of patients >22 years and QT grafts. Validating the MOON calculator for a broader age range and QT grafts could enhance its clinical applicability.

Data on the clinical outcomes of combined medial patellofemoral ligament (MPFL) and medial quadriceps tendon femoral ligament (MQTFL) reconstruction for patellar instability remain scarce. A systematic literature search was conducted in Web of Science, Embase, and PubMed on June 9, 2025. All studies reporting clinical outcomes after combined MPFL/MQTFL reconstruction for patellar instability were included. Methodological quality was assessed using the Methodological Index for Non-Randomized Studies (MINORS). General characteristics, surgical technique, clinical outcomes, satisfaction, and complications were recorded. Five studies comprising 180 patients (188 knees) were included. The mean age was 14.8 years (range 12-22 years), and the mean follow-up was 34.6 months (range 24-49 months). Children and adolescents accounted for 67.8% of the cohort (n = 122). The mean Insall-Salvati ratio (ISR) or Caton-Deschamps index (CDI) was 1.2, and the mean tibial tubercle-trochlear groove (TT-TG) distance was 16.6mm. Trochlear dysplasia was present in 86.2% of knees (162/180). Allografts were the most commonly used grafts (n = 103, 54.8%). Methods of quadriceps tendon fixation included soft tissue tunnel fixation (n = 61, 37.2%), and soft tissue suture fixation (n = 103, 62.8%). The overall complication rate was 8.0% (15/188), with recurrent dislocation occurring in 2.1%. No patellar fractures or growth distrubances were reported. Combined MPFL and MQTFL reconstruction is a safe and effective technique for treating patellar instability in both pediatric and adult patients, demonstrating low rates of recurrent dislocation and complications. However, the optimal surgical technique remains controversial.

The quiet revolution in anterior cruciate ligament grafting: An international survey of current global practices in quadriceps tendon use.

Background:Anterior cruciate ligament (ACL) injuries are among the most common sports-related injuries, accounting for about half of all knee injuries, and most athletes opt to undergo ACL reconstruction (ACLR). The quadriceps tendon (QT) ACLR has only recently been gaining popularity, and therefore few studies exist for evaluating the healing, or ligamentization, timeline of the QT autograft.Purpose:To evaluate the signal intensity (SI) ratio of the tendon QT autograft after ACLR during the first postoperative year.Study Design:Case series; Level of evidence, 4.Methods:A prospective case series of 19 athletes (mean age = 15.63 years) with ACL rupture who underwent ACLR with a QT autograft underwent knee magnetic resonance imaging (MRI) at 4 time points: presurgery (PRE), 3 months postoperative (3M), 6 months postoperative (6M), and 12 months postoperative (12M). SI ratio was calculated across different anatomic landmarks, specifically the intra-articular tissue of the native ACL of the contralateral knee from the PRE time point; the QT graft in the intra-articular space at 3M, 6M, and 12M time points; and the posterior cruciate ligament at each visit, to be used as a reference value and account for visit-to-visit variations in the MRI signal. Means of the SI ratio were calculated at the full graft level, as well as segmented into either 4 or 24 segments for analysis.Results:At the full-graft level, there was a significantly higher SI ratio in the QT graft at 3M and 6M compared with the native contralateral ACL. By 12M, the full graft was most like the native contralateral ACL. Similarly at the 4 subsegment level, all regions except the distal segment had significantly higher SI ratios at 3M and 6M as compared with the native contralateral ACL. By 12M, all subsections of the graft were not significantly different from the native contralateral ACL.Conclusion:The SI ratio of QT graft was increased at 3M and 6M after surgery and then returned close to that of the native ACL by 12M after surgery, which is largely consistent with the published maturational timeline of patellar tendon and hamstring tendon autografts.

Variations in graft maturity between quadriceps tendon and semitendinosus tendon at 6 months after anterior cruciate ligament reconstruction: A quantitative assessment using UTE-T2* mapping.

Beyond four heads: Should the quadriceps femoris be reclassified as multiceps muscle?

PurposeQuadriceps tendon (QT) autograft is increasingly used for anterior cruciate ligament reconstruction (ACLR), yet rehabilitation guidelines remain extrapolated from patellar tendon (PT) or hamstring tendon (HT) protocols. This cross‑sectional study evaluated publicly available postoperative rehabilitation protocols from academic orthopaedic programmes to describe their content, assess variability and identify key trends.MethodsAccredited orthopaedic residency programmes were identified through the Electronic Residency Application Service (ERAS) and Canadian Resident Matching Service (CaRMS). A three‐step systematic web‐based search was conducted to identify publicly available QT‐ACLR rehabilitation protocols. Protocols were included if specific to QT autografts and excluded if addressing concomitant meniscal repairs. Two independent reviewers extracted data on rehabilitation components and timelines. The proportion of protocols including each component and the median initiation time were calculated.ResultsOf 219 programmes screened, 16 eligible protocols were identified. Nine were QT‐specific and seven were general ACLR protocols. Key trends included: (1) use of a hinged brace locked in extension for 2–4 weeks (86.7%); (2) initiation of icing, cryotherapy and patellar mobilizations immediately postoperatively (68.8%); (3) neuromuscular electrical stimulation use within the first 4 weeks (56.2%); (4) target of full extension by 2–4 weeks and flexion by 3–4 months (100%); (5) strengthening, balance and proprioceptive training beginning between 1–3 months (93.8%–100%) and (6) return‑to‑sport (RTS) testing between 5 and 9 months, using time‐based and/or criterion‐based recommendations (100%). Substantial variability existed in exercise prescriptions, adjunctive therapy use and RTS criteria.ConclusionsPublicly available QT‐ACLR rehabilitation protocols from academic programmes emphasize early weight‐bearing, range of motion restoration and progressive strengthening but reveal considerable variability in timing, adjunctive therapies and RTS guidelines. Many protocols mirror those for PT and HT autografts rather than being tailored to QT‐specific considerations. Standardized, evidence‐based rehabilitation guidelines that address graft‐specific risks, psychological readiness and telehealth delivery are needed to optimize outcomes following QT‐ACLR.Level of EvidenceLevel IV.

Background:Perioperative nerve blocks are commonly used for regional analgesia with anterior cruciate ligament (ACL) reconstruction (ACLR). Liposomal bupivacaine (LB) is a long-acting anesthetic agent providing up to 72 hours of nerve blockade. It is theorized that the addition of dexamethasone to LB (LB+dex) may prolong the analgesic duration.Purpose:To characterize pain control and opioid consumption with adductor canal block (ACB), interspace between the popliteal artery and capsule of the posterior knee (iPACK), and suprasartorial infiltration (SSI) regional anesthetic techniques utilizing LB after ACLR and to compare LB versus LB+dex.Study Design:Randomized controlled trial; Level of evidence, 1.Methods:Patients undergoing primary ACLR using bone–patellar tendon–bone or quadriceps tendon autograft were included. All patients received an ACB, iPACK, and SSI preoperatively. Patients were randomized to receive either LB or LB+dex for their anesthetic agent. Opioid consumption, visual analog scale (VAS) scores, pain control satisfaction, and duration of block effect were recorded postoperatively.Results:A total of 131 patients were included in the analysis. The mean opioid consumption for all patients was 1.20 ± 2.42 five-mg oxycodone tablets (8.97 ± 18.12 morphine milliequivalents [MME]). We did not observe a significant difference in oxycodone consumption between cohorts during the study period (1.42 ± 2.92 vs 0.97 ± 1.91; 10.65 ± 21.90 MME vs 7.28 ± 14.33 MME; P = .76). An estimated 95.2% of opioids prescribed went unused and 77.1% (101/131) of patients consumed no opioids. There was no significant difference in VAS score, patient satisfaction, or duration of block effect between cohorts.Conclusion:A single shot of LB with or without dexamethasone via ACB, SSI, and iPACK block provided excellent pain control and minimized opioid consumption after autograft ACLR. Nearly 80% of patients did not require opioids postoperatively, making opioid-free ACLR a realistic possibility for many patients. When narcotics were required, the dose of opioids was minimal; patients required 1.2 tablets of oxycodone on average, and >95% of the opioids prescribed went unused. Despite previous reports suggesting a prolonged duration of anesthetic effect when LB is combined with dexamethasone, we found no difference in opioid consumption, VAS score, patient satisfaction, or duration of block effect when patients received dexamethasone with their regional block. The utilization of regional anesthetic techniques such as ACB, SSI, and iPACK blocks in conjunction with LB-based anesthetics could allow providers to curtail or potentially eliminate opioid prescriptions after ACL surgery.Registration:NCT06006624 (ClinicalTrials.gov identifier).

Prognostic indicators of lower extremity functional recovery after anterior cruciate ligament reconstruction.

This study aimed to quantitatively assess relative arterial contributions to the quadriceps tendon (QT) using 7-Tesla quantitative magnetic resonance imaging (7T-qMRI), histology and high-resolution computed tomography (micro-CT) in a fresh-frozen human cadaveric model. Six human cadaveric knee pairs were obtained (mean age: 43 years; range: 23-61 years). Pre- and post-contrast 7T-qMRI scans were performed to quantify tendonous vascularity. Subsequent algorithm-based quantitative histologic analysis was performed using hematoxylin and eosin staining, with validation by CD31 immunohistochemistry. Qualitative analysis was performed on two additional knee specimens using 98 μm micro-CT imaging. The distal QT demonstrated higher median arterial contributions versus central and proximal regions (distal, 47.4% [interquartile range: 30.8%-64.1%]; central, 28.6% [20.4%-41.5%]; proximal, 11.6% [8.7%-18.4%]), with significantly greater contributions distally versus proximally (Cohen's d = 1.58; p = 0.021). These findings aligned with the sagittal sub-analysis (deep-proximal 17.2 ± 19.3% vs. deep-distal 43.4 ± 20.3%; Cohen's d = 1.32; p = 0.050). Histologic analysis (interobserver-reliability: r = 0.95) corroborated the MRI results (distal QT, 43.5 ± 7.9%; central, 30.7 ± 6.4%; proximal, 25.8 ± 4.1%), with significant differences between distal and both proximal (Cohen's d = 2.81; p < 0.001) and central (Cohen's d = 1.78; p = 0.012) regions. The deep layer was found to have significantly higher arterial contributions (61.6 ± 14.2%) versus the superficial layer (38.4 ± 14.2%) (Cohen's d = 1.64; p = 0.018). The medial and lateral QT demonstrated lower arterial contributions versus middle QT (Cohen's d = 0.96-1.26; p > 0.050). 7T-qMRI and algorithm-based histological analysis of arterial QT contributions revealed significantly greater arterial contributions in the distal compared to the proximal as well as in the deep compared to the superficial region. While the central region demonstrated higher arterial contributions than the medial and lateral aspects, these differences were not statistically significant. Given that the majority of injuries affect the distal and central portions of the QT, these findings reinforce the rationale for direct tendon-to-bone repair; however, clinical studies are necessary to confirm these findings. Level V, cadaveric study.

Quadriceps tendon malalignment has been closely linked to chronic lateral patella tracking and the development of lateral patellar facet osteoarthritis. The underlying deformity of the quadriceps muscle associated with quadriceps tendon malalignment is unknown. A common assumption is that patella maltracking is associated with wasting of the vastus medialis. The purpose was to: (1) determine the association of the alignment of the quadriceps musculature with quadriceps tendon alignment, (2) assess the torsional deformity of the quadriceps along the femur and (3) determine the association of quadriceps deformity with the relative volume of the four components of the quadriceps. Quadriceps tendon axial angle (QTAx) was measured in 176 computed tomography scans. Ten cases with the most lateralised and medialised QTAx were respectively grouped into the Lateralised and Medialised groups while 10 cases around the median were grouped into the Normal group. The quadriceps muscle torsional angle (QMuscle) was measured along the femur and compared to the QTAx groups. The mean cross-sectional area of the quadriceps muscle bellies was also measured and compared between QTAx groups. There were significant differences in QMuscle between the QTAx groups at all seven points along the femur, with the lateralised group having the largest mean angle of 46.6° (±7.5°) external rotation across all sections, compared to normal and medalised groups (p < 0.001). The ratio of the vastus medialis to the total quadriceps muscle was significantly greater in the lateralised group when compared to the normal group (p < 0.001). Lateralisation of the quadriceps tendon is highly correlated with the external rotation of the quadriceps muscle along the femur. Quadriceps malalignment is also associated with a larger vastus medialis muscle volume. These results demonstrate that chronic lateral patella tracking is likely to be due to a rotational deformity of the quadriceps muscle and not to wasting of the vastus medialis. Level III, case-control study.

Introduction The use of hamstring tendon (HT) autografts in anterior cruciate ligament (ACL) reconstruction has reduced in New Zealand after registry data demonstrated a higher revision rate. In contrast, the use of quadriceps tendon (QT) autografts has increased, but it is unclear whether it has a lower revision rate than the bone-patellar tendon-bone (BTB) autograft. Methods Prospective data from the New Zealand ACL Registry were analyzed. Primary ACL reconstructions performed between 2014 and 2022 with a minimum follow-up of two-years were eligible. The primary outcome was revision. Secondary outcomes included patient-reported kneeling difficulty, the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Marx activity score. Multivariable analysis was performed via Cox regression survival analysis to calculate hazard ratios (HR) adjusted for age, gender, timing of surgery and meniscal injuries. Results 15,687 primary ACL reconstructions were analyzed, of which 4,424 used a BTB graft (28%), 574 used a QT graft (4%) and 10,689 used a HT graft (68%). The BTB graft had the lowest revision rate of 3.1% compared to 4.4% with the QT graft and 6.1% with the HT graft (p&lt;0.001). On multivariable analysis, the QT graft (HR = 1.7, p = 0.01) and the HT graft (HR = 2.3, p&lt;0.001) had a higher risk of revision when compared to the BTB graft. The BTB graft had the highest incidence of kneeling difficulty at 2-year follow-up (16.4%) when compared to the QT (13%) and HT (9.8%, p&lt;0.001) grafts. Despite this, the BTB graft had better KOOS and Marx activity scores when compared to the QT and HT grafts. Discussion/Conclusion The BTB graft has a lower revision rate than both the QT and HT grafts. Patients with a BTB graft are more likely to report difficulty with kneeling, but still report better KOOS and Marx activity scores at 2-year follow-up.

Background. Thyroid hormone regulates energy metabolism in the musculoskeletal system. Patients with hypothyroidism (HT) commonly complain of muscle and joint pain. The interaction between thyroid dysfunction and autoimmune diseases can be attributed to common autoimmune mechanisms and systemic inflammation. This observational cross-sectional study aimed to detect articular and extra-articular changes by musculoskeletal ultrasonography (MSUS), then score them using the combined OMERACT score for joints and the Madrid Sonographic Enthesitis Index (MASEI) in patients with chronic hypothyroidism to help early detection of associated autoimmune diseases. Results. MSUS revealed hypoechogenicity (MASEI-inflammatory score) as the most frequent finding, mainly in the plantar fascia, Achilles, quadriceps tendons and the common extensor tendons (CXT). Calcifications (enthesophytes) indicated by the MASEI-damage score were common in the Achilles, quadriceps, and CXT. Grade I synovitis predominated in the wrist, MCP, and knee joints, while Grade II synovitis with power Doppler (PD) positivity was seen in 21% of wrists and in 41% of knee joints (7% with PD). Paratenonitis was found in 27% of patients. OMERACT and MASEI scores correlated positively with TSH and CRP (p &lt; 0.001) and negatively with fibromyalgia (p &lt; 0.001), which was present in 52% of cases. Homocysteine correlated significantly with MASEI (p &lt; 0.001). Conclusions. Musculoskeletal ultrasonography may be a helpful tool to reveal inflammatory pattern changes and coexisting rheumatologic conditions in hypothyroidism. We suggest further controlled studies for follow-up of the serial changes and MSUS findings in patients with chronic hypothyroidism.

Background:Restoring knee extensor strength after anterior cruciate ligament (ACL) reconstruction using a quadriceps tendon (QT) autograft remains challenging. Whether altered quadriceps neuromuscular activity contributes to this weakness is unclear.Hypothesis:Quadriceps strength recovery after ACL reconstruction using QT would be impaired owing to altered quadriceps neuromuscular activity.Study Design:Cross-sectional study; Level of evidence, 3.Methods:A total of 31 patients (Tegner activity scale score ≥7) who had undergone ACL reconstruction 4 months earlier were enrolled into either the QT group (n = 15) or hamstring tendon (HT) group (n = 16). Knee extensor strength was assessed using maximum voluntary isometric and isokinetic (60 deg/s) force. Neuromuscular activity of the vastus lateralis (VL) and vastus medialis (VM) during isometric contraction was recorded with high-density surface electromyography to evaluate motor unit discharge rate (MU DR). A generalized linear mixed-effects model was used to test side (involved and uninvolved limbs) and task (25%, 50%, and 70% of isometric contraction) effects, and regression analysis was used to examine associations between side-to-side isometric strength and MU DR differences.Results:Baseline characteristics did not differ significantly between the QT (9 males, 6 females; mean age, 17.1 ± 3.9 years) and HT (10 males, 6 females; mean age, 18.2 ± 2.7 years) groups. The mean time from surgery to testing was also similar (QT group: 120.8 ± 8.0 days; HT group: 121.3 ± 7.2 days). The limb symmetry index for isometric strength showed no difference (QT group: 75.0% ± 19.6%; HT group: 78.2% ± 14.3%; P = .63). In contrast, isokinetic strength at 60 deg/s was significantly lower in the QT group (70.5% ± 13.2%) than in the HT group (83.9% ± 11.6%) (P < .01). In the QT group, MU DR showed a side × task interaction, with higher discharge in the involved (11.7 ± 3.2 pluse per second [pps]) versus uninvolved (10.4 ± 1.9 pps) limbs during 70% isometric contraction in VM (P < .01). Correlations were observed between isometric strength differences and MU DR in both VL (r = 0.65; P = .01) and VM (r = 0.67; P = .01).Conclusion:Neuromuscular changes were evident in the QT group, particularly in the VM, but not in the HT group. Notably, in the QT group, altered MU activity was correlated with muscle strength decline.

Anatomical variability in the quadriceps tendon: structural layering and patellar insertion patterns.

Changes in MRI T2 mapping value in quadriceps tendon harvest donor site after anterior cruciate ligament reconstruction reflects tendon maturation and correlates with clinical scores.

Background:The COVID-19 pandemic led to increased sedentary behavior and body mass index during 2020, which may decondition musculotendinous units and lead to increased risk for injury. As patients return to pre-COVID levels of activity, we hypothesize that there will be a resultant rebound increase in tendon ruptures.Level of Evidence:III, descriptive epidemiology study.Methods:The electronic medical record was queried for current procedural terminology codes for tendon ruptures (Achilles, patella, quadriceps, hamstring, distal biceps, triceps, and pectoralis major) from January 2017 to December 2021 at a single academic urban center. Data were reviewed to ensure only acute tendon rupture repairs were included. The years 2017–2019 were used as a proxy for pre-COVID rates, 2020 as a proxy for the COVID quarantine, and 2021 as a proxy for “post-COVID” activity. Univariate analysis was performed for comparative data.Results:A total of 1,879 patients (82.8% male, mean age 47.8 years) who sustained tendon injuries and underwent surgical repair were identified. There were 589 (31.3%) Achilles tendon repairs, 181 (9.6%) patella tendon repairs, 414 (22.0%) quadriceps tendon repairs, 100 (5.3%) hamstring tendon repairs, 397 (21.1%) distal biceps repairs, 105 (5.6%) triceps repairs, and 93 (4.9%) pectoralis tendon repairs. The total number of tendon injuries per year was 2017—357 (19.0%), 2018—380 (20.2%), 2019—380 (20.2%), 2020—308 (16.4%), and 2021—454 (24.2%). The rates in 2017, 2018, and 2019 were within 1% of each other, but there were a 3.8% decrease in rate of tendon injuries from 2019 to 2020 and a 7.8% increase in rate of tendon injuries from 2020 to 2021. When analyzed by quarter, a linear regression model demonstrated a statistically significant increase in case counts over the period from Q2 2020 to Q2 2021 (β = 21.20; 95% confidence interval = 13.62–28.78, P-value < .01).Conclusions:A “COVID rebound” of tendon rupture repairs in 2021 from a prolonged period of inactivity during 2020 occurred at a single academic center. As patients return to pre-COVID levels of activity that may be unsuitable to their deconditioned state, healthcare providers should counsel patients appropriately on return to activity or sport following long periods of induced inactivity.