BACKGROUND:Stable osteochondritis dissecans (OCD) lesions are primarily treated nonoperatively. Nonoperative treatment includes several recommendations, including the use of an unloader brace. However, little is known about the clinical effectiveness of unloader bracing and its influence on OCD healing, return to sports, and patient-reported outcomes (PROs). The purpose of this investigation was to evaluate the impact of unloader bracing on patients with stable medial femoral condyle (MFC) OCD lesions treated nonoperatively. PURPOSE:To investigate the influence of valgus unloader bracing on the success of treating stable MFC OCD with nonoperative treatment strategies. STUDY DESIGN:Cohort study; Level of evidence, 2. METHODS:The authors used a prospective cohort of patients receiving nonoperative care for stable MFC knee OCD lesions. The primary variable of interest was the efficacy of bracing. The primary outcomes were transition from nonoperative care to surgical intervention, return-to-play (RTP) clearance, and PROs. Bivariate testing was used to determine if there were differences between groups. Chi-square testing was used to determine if there were differences in rates of transition to surgery by group. The timing of the transition by each group was assessed using a Wilcoxon rank-sum test, given the nonparametric nature of the data. Kaplan-Meier survival analysis was used to calculate time at risk, incidence rate, and survival times for each group. RESULTS:A total of 185 knees (bracing group: 123 [66.5%] knees; no-bracing group: 62 [33.5%] knees) were analyzed. Overall, 142 (76.8%) knees were successfully treated nonoperatively. Transition to surgery occurred in 43 (23.2%) knees. There were no differences in transition to surgery by groups, with no differences seen by group. Of the knees that did not transition to surgical care, 65 (71.4%) in the bracing group and 38 (74.5%) in the no-bracing group received RTP clearance (P = .693). PRO scores were similar between the 2 groups at the time of RTP clearance. CONCLUSION:The inclusion of an unloader brace in the nonoperative treatment for stable MFC OCD lesions did not decrease the likelihood of patients undergoing surgical intervention or improve their PRO scores at the time of RTP clearance. REGISTRATION:NCT02771496 (ClinicalTrials.gov identifier).

Objective:Anterior cruciate ligament (ACL) tears increase the risk for developing posttraumatic osteoarthritis (PTOA). Females have greater risk for both. However, studies defining sex-specific protein responses in human cartilage after ACL injury are lacking. We hypothesize that articular cartilage's response to an injurious environment differs depending on sex. Design:We compared the proteomic profiles of normal cartilage with injured cartilage harvested from the intercondylar area during ACL surgery. Sex-specific injury effects were estimated through contrasts between Injured Male and Normal Male and between Injured Female and Normal Female. Pathway enrichment analysis was done using gene ontology (GO) and compared against the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Extracellular matrix (ECM) proteins were further analyzed using the Matrisome AnalyzeR. Results:From the 2,188 proteins identified, males and females shared 1,121 upregulated and 23 downregulated proteins in injured compared to normal cartilage. Analysis of ECM proteins and enriched pathways revealed mostly similar male and female responses to an injurious environment, with evidence of early cartilage remodeling in both sexes. Nevertheless, more than 240 proteins were affected specifically by sex, and significant sex differences were found in inflammation, ECM-related, and metabolic pathways. Males were enriched mostly in "ECM-receptor interaction", while females were enriched in "Citrate cycle (TCA cycle)", "Fatty acid degradation", and "Fatty acid metabolism" pathways. Conclusion:Articular cartilage shows signs of remodeling soon after ACL injury, even when only exposed to an injurious environment rather than being physically impacted. Sex differences were observed in inflammation, metabolic pathways, and ECM synthesis.

Lateral patellar instability is one of the most common knee conditions among adolescents, with an estimated incidence of approximately 43 per 100,000 individuals. Trochlear dysplasia has been identified as the most common anatomic risk factor for patellar instability and may be present in up to 90

BACKGROUND:Root fixation for medial meniscal transplantation can be performed with or without bone plugs. Bone plug fixation has generally been shown to have superior time-zero biomechanical characteristics. Little is known about the biomechanics of peripheral stabilization for meniscal allograft transplantation (MAT) and its ability to improve time-zero biomechanics. PURPOSE/HYPOTHESIS:The purpose was to compare the biomechanical effectiveness of modern soft tissue (ST) root fixation versus bone plug (BP) root fixation as well as peripheral stabilization in MAT. The hypothesis was that, while BP root fixation likely has better time-zero biomechanical characteristics with regard to contact forces and laxity, the addition of peripheral stabilization would mitigate these differences for either type of root fixation in a cadaveric model. STUDY DESIGN:Controlled laboratory study. METHODS:A total of 8 matched-pair cadaveric knees with a mean age of 55 ± 10 years (5 female and 3 male) were used. The knees were tested in the following states: intact, meniscectomy, MAT (with either BP or ST root fixation) with peripheral stabilization, and MAT (with either BP or ST root fixation) without peripheral stabilization. Medial tibiofemoral joint contact area and pressure as well as knee laxity for anterior-posterior tibial translation, external-internal rotation, and varus-valgus were quantified at 0°, 30°, 60°, and 90° of knee flexion. A paired t test with a significance level at .05 was used for statistical analysis. RESULTS:There were small but significant differences between ST and BP MAT with or without peripheral stabilization in contact forces and most laxity measurements. While both groups demonstrated improved stability with peripheral stabilization, the BP MAT group exhibited greater influence from stabilization in laxity with internal-external rotation (P = .010), contact area with internal-external rotation (P = .022), and contact area with varus (P < .005). CONCLUSION:This study demonstrated the slight superiority of BP versus ST root fixation and that the addition of peripheral stabilization for ST and BP MAT decreased medial tibiofemoral joint contact pressure and increased medial tibiofemoral joint contact area at time zero. While the time-zero biomechanical characteristics of BP MAT were more influenced by peripheral stabilization than the ST technique, this is most likely because of graft size mismatch. CLINICAL RELEVANCE:With current root fixation devices, both ST and BP MAT had generally similar biomechanical characteristics at time zero, and peripheral stabilization seemed to improve both modes of fixation.

Background:Because of congenital abnormal collagenous structures and peripheral attachments, discoid lateral meniscus (DLM) is often associated with tears and instability and a risk of premature compartmental articular degeneration. Typically, surgery is indicated for symptomatic patients. Several surgical techniques have been described in the literature, but no studies have examined surgeon variation. Purpose:To determine the intersurgeon agreement for DLM surgical planning and postoperative restriction after arthroscopic assessment. Study Design:Cross-sectional study. Methods:Sixteen orthopaedic surgeons from an international pediatric meniscus study group were shown 4 different videos of a DLM arthroscopic procedure. Each surgeon completed a survey for each arthroscopic video. The survey included questions about operative planning, such as peripheral rim preservation, repair and stabilization technique, and postoperative restrictions. Descriptive statistics were used to characterize the variables collected. Results:One of the 4 arthroscopic videos showed a complete discoid meniscus with no instability or tearing. For this specific meniscus, consensus was generally good, with 87.5% to 93.8% agreement for all the categories, except peripheral rim preservation, with 31.3% agreement. However, for the other 3 videos with tears and/or instability, consensus was generally low. Depending on the categories, the highest percentage of intersurgeon agreement varied between 25.0% and 62.5%, while being >50% only 2 of 27 times. Conclusion:Agreement regarding the surgical technique and postoperative rehabilitation among surgeons with experience in the treatment of DLM is poor in the event of tears and instability, which represent the greatest technical challenges with the most significant functional effect. Given the relative rarity of the condition and the implications on a child's long-term joint health, prospective, comparative multicenter studies regarding treatment algorithms and outcomes are warranted.

Purpose: To compare outcomes of anterior cruciate ligament reconstruction (ACLR) with and without suture tape augmentation (STA) in adolescent patients. Methods: Retrospective review of patients between 12 and 18 years of age who had ACLR with quadriceps tendon autograft between 2017 and 2022 with a minimum 2-year follow-up. Charts were reviewed for demographics and surgical data. Two groups were created: ACLR with STA (+STA) and ACLR without STA (–STA). Comparisons between continuous variables were performed using Student t tests or Mann-Whitney U tests. Comparisons between categorical variables were performed using χ2 or Fisher exact test. Results: In total, 110 patients were included in analysis. There was no significant difference in demographics between groups. There was a significant difference between the percentage of extra-articular procedures with 4% in the –STA group and 29% in the +STA group (P < .001). No difference was seen in femoral tunnel size (P = .27), tibial tunnel size (P = .20), or concomitant meniscal repair or resection (P = .88) between groups. There was no significant difference in the number of anterior cruciate ligament graft failures (P = .61) or time to failure between groups (P = .62). There were 9 failures (13.2%) in the –STA group and 7 failures (16.6%) in the +STA group, with a median of time to failure of 698 days and 355 days in the –STA and +STA group, respectively. Of the patients, 19.1% in the –STA group and 31.0% in the +STA group underwent lysis of adhesions (P = .16). Conclusions: In our study population of adolescents undergoing primary, unilateral ACLR with quadriceps tendon autograft, we found no difference in the number of graft failures or time to failure based on the use of suture tape augmentation. Additionally, we found no difference in arthrofibrosis rates between groups. Level of Evidence: Level III, retrospective cohort study.

Background: Considerable variability exists in the described clinical and radiographic indications for use, surgical techniques, postoperative management, and risk profile after trochleoplasty for the management of patellofemoral instability (PFI). In areas of clinical uncertainty, a cohesive summary of expert opinion and identification of areas of variation in current practice can be useful in guiding current practice and future research efforts. Purpose: To assess the current indications for use, surgical techniques, postoperative rehabilitation practices, and observed complication profile for trochleoplasty in the management of PFI among surgeons who perform this procedure. Study Design: Cross-sectional study. Methods: A 21-item cross-sectional survey was developed to evaluate trochleoplasty in its current practice among surgeons around the world. The survey was distributed between December 2021 and April 2022 to the orthopaedic surgeon membership of multiple national and international knee, arthroscopy, and sports medicine societies to identify any surgeon with experience performing the trochleoplasty procedure in practice for the management of PFI. Descriptive statistics of survey responses were performed to address study aims, and univariate analyses were performed to compare differences between high- and low-volume trochleoplasty surgeons. Results: Survey distribution identified 32 orthopaedic surgeons with experience performing the trochleoplasty procedure. Procedural indications were most commonly felt to be met with Dejour classification of B or D on magnetic resonance imaging. Trochleoplasty was felt by most to be appropriate as a primary surgical intervention for PFI. A majority of surgeons utilized a Bereiter (thin-flap) trochleoplasty technique with suture-based fixation and performed concurrent medial patellofemoral ligament reconstruction, but other concomitant procedures varied. Range-of-motion precautions and bracing practices varied among respondents, and arthrofibrosis was the most frequently cited observed complication. High- and low-volume trochleoplasty surgeons differed in their radiographic and age-based indications for the procedure. Conclusion: Study findings indicated that variation exists in the surgical indicators, technique, and postoperative rehabilitation practices of trochleoplasty surgeons, with specific differences noted between high- and low-volume trochleoplasty surgeons. The results of this survey identified areas of equipoise and treatment variation that should direct future research efforts in the study of the trochleoplasty procedure.

Background:Trochlear dysplasia is frequently seen in young patients and can be a cause of patellar instability (PI). A lateral trochlear inclination (LTI) of 11° or less has long been utilized to discriminate between patients with and without some degree of trochlear dysplasia that is likely to contribute to recurrent PI. The traditional methodology for this radiographic measure has been described via a single-image technique. Recently, a 2-image technique was introduced to better account for distal femoral orientation relative to proximal trochlear cartilage. However, further work is required to determine the validity of the 2-image LTI technique in introducing a new diagnostic threshold value for trochlear dysplasia. Purpose/Hypothesis:The purpose of this study was to evaluate the validity of the novel 2-image LTI measurement technique in determining a diagnostic cut-off value for trochlear dysplasia that is likely to result in recurrent PI. It was hypothesized that this would yield a different value than the historical 11° cutoff determined through the single-image technique. Study Design:Cohort study (Diagnosis); Level of evidence, 3. Methods:After institutional review board approval, medical records were retrospectively reviewed to form a PI group and a control (no PI) group. The 2-image LTI was first measured by 2 raters to determine intrarater and interrater reliability. A receiver operating characteristic curve was created to determine a diagnostic cut-off value. After applying this cutoff between the groups, the resultant sensitivity and specificity were calculated. Results:The 2-image LTI measurements demonstrated excellent intrarater and interrater reliability. The PI group had a mean LTI of 2.58°, while the control group had a mean LTI of 17.26°. A diagnostic threshold LTI value of 13.7° was determined, discriminating between patients with and without recurrent PI due to trochlear dysplasia, with a sensitivity of 0.889 and a specificity of 0.780. The area under the curve was 0.887. Conclusion:Utilizing the 2-image LTI measurement technique, a threshold value of 13.7° was determined as optimal for discerning between patients with and without trochlear dysplasia that is likely to lead to recurrent PI. This value can thus be used for accurate diagnoses of trochlear dysplasia, which can help to inform management, patient counseling, and research in the future.

Background:A lateral dislocation of the patella is a common injury in adolescents and young adults that is largely caused by underlying anatomic risk factors. Surgically managed patients have a significantly lower risk of recurrent dislocations. However, determining the optimal surgical treatment remains a challenge, with patients sometimes undergoing multiple surgical procedures before achieving successful stabilization. Purpose:To computationally evaluate patients who have undergone multiple surgical procedures to treat recurrent lateral patellar dislocations and predict their clinical outcomes. Study Design:Controlled laboratory study. Methods:Our cohort consisted of 16 patients with trochlear dysplasia and recurrent lateral patellar dislocations. We used magnetic resonance imaging to create 3-dimensional patient-specific finite element models of the knee joint and evaluated patellofemoral stability before and after surgery. We applied these models to computationally predict the clinical outcome of each surgical procedure. We simulated a knee extension activity coupled with external tibial torsion to assess patellofemoral stability. We also included a healthy control group of 12 participants in the computational evaluation. Finally, we developed and trained a logistic regression model based on anatomic risk factors and applied this model to classify whether patients had a likelihood of a dislocation to efficiently differentiate between surgical outcomes. Results:Of 12 control, 12 preoperative, and 9 postoperative scans, the finite element model correctly predicted 29 of 33 surgical outcomes (87.9% accuracy). Postoperative simulations predicted patellofemoral stability metrics similar to those of the control group. Specifically, patients after trochleoplasty were associated with increased constraint force on the patellar lateral facet and lower involvement of the medial patellofemoral ligament. The logistic regression model demonstrated 81.8% accuracy in classification. Conclusion:Preliminary results are promising, but an improvement of the model and a larger clinical dataset are necessary to increase accuracy and comprehensively validate model performance. Clinical Relevance:The aim of this study was to provide surgeons with a useful computational tool that can predict the likelihood of a patellar dislocation and differentiate, before a clinical intervention, between successful versus unsuccessful surgery to determine the optimal treatment pathway for individual patients.

Meniscus repair has increased in frequency, especially among surgeons who focus on youth sports injuries. The aim of this study was to determine current trends in meniscus repair among a specific subset of meniscus repair surgeons. A cross-sectional survey utilizing several clinical vignettes was administered to orthopaedic surgeon members of the Pediatric Research in Sports Medicine (PRiSM) Society to investigate surgeon experience and training, number of meniscus repair procedures performed, and surgical and rehabilitation preferences. A statistical analysis of the responses was performed to determine associations between years in practice or type of fellowship training and the number of meniscus repair procedures performed, surgical indications, and rehabilitation preferences. The response rate to various questions ranged from 61.5 (59/96) to 63.5% (61/96). In all vignettes, a majority favored repair as well as some degree of weight-bearing and range-of-motion restrictions. Surgeons who had been in practice for 6 to 10 years performed significantly more meniscus repairs per year than those who had been in practice for greater than 20 years ( p = 0.009) and those who had been in practice for 0 to 5 years ( p = 0.05). Surgeons who had been in practice for greater than 20 years performed a significantly higher percentage of meniscectomies relative to meniscus repairs, compared with those in practice for 0 to 5 years ( p = 0.002) or 6 to 10 years ( p = 0.0003). When surgeons were grouped into those with less than 10 years of experience and those with greater than 10 years of experience, the former group performed a significantly higher number of meniscus repairs relative to meniscectomies than the latter group of surgeons ( p < 0.0001). Less experienced surgeons are more likely to perform meniscus repair than meniscectomy, but all surgeons surveyed had a general preference for repair in all clinical vignettes. Repair technique preferences as well as rehabilitation protocols varied widely among surgeons.

Lateral patellar instability is one of the most common knee disorders among adolescents. Numerous anthropometric features, including trochlear dysplasia, patella alta, high tibial tubercle-to-trochlear groove distance, and coronal and rotational plane malalignment, are considered primary risk factors for patellar dislocation, and the understanding of their complex interplay is continuously evolving. Because of the multifactorial nature of patellar instability, there is a lack of consensus regarding many aspects of surgical intervention. Medial patellofemoral ligament reconstruction is considered to be the essential procedure in preventing recurrent instability. However, there is growing interest in addressing underlying anatomic risk factors that contribute to patellar instability. It is important to discuss the diagnosis and management of patellar instability, surgical considerations in medial patellofemoral ligament reconstruction, mitigation/correction of anatomic risk factors, and treatment of associated chondral lesions.

Management of meniscal radial and root tears and extrusion is complex and has changed significantly over recent years. It is important to provide a comprehensive overview of the management of radial and root tears and meniscal extrusion and be aware of the currently available evidence on repair techniques, rehabilitation, and outcomes following radial and root repairs.

Background/Objective: To share technical pearls of a basic knee arthroscopy in a pediatric patient by presenting tips and tricks used by experienced pediatric arthroscopists. Indications: Knee arthroscopy is a common procedure performed by most orthopedic surgeons. However, technical considerations and equipment should be considered before performing this procedure in a pediatric patient. This video provides information on indications, equipment, and patient positioning, as well as outlining a systematic approach to diagnostic arthroscopy and pertinent pediatric anatomy. Discussion/Conclusion: This video provides an excellent overview as well as specific pathology-dependent considerations for the inexperienced orthopedic surgeon, or the orthopedic surgeon who rarely performs knee arthroscopy. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Purpose:To determine the extent of variability in meniscus size and anthropometric data between donors (supply) and patients (demand), to evaluate potential factors that may contribute to size discrepancies, and to determine whether the discrepancies lead to longer patient wait times.Methods:Lateral and medial meniscal measurements, anthropometric data, and time to match a donor graft were extracted from a tissue supplier database. The frequency and distribution of meniscus size were analyzed. Body mass index (BMI), relative meniscus area, body mass to meniscus area index, and height to meniscus area index were compared between patient and donor pools via χ2 tests and independent samples t-test. The effect of size on time to match was analyzed using analysis of variance and post-hoc Tukey test.Results:The lateral meniscus patient population showed a greater frequency of larger size requirements compared to the donor population (P < .001) and the medial meniscus patient population showed a higher frequency of smaller meniscus size requirements (P < .001). The medial meniscus analysis showed significantly smaller meniscus areas (P < .001) in the patient population contributing to the observed trend of an increased body mass to meniscus area index and height to meniscus area index. The time to match a donor meniscus was affected by the patient meniscus size.Conclusions:This analysis demonstrates variations in frequency of meniscus sizes between donor and patient populations. This variation is attributed to differences in anthropometric data between patient and donor populations. This work identifies a mismatch between demand and supply for certain patient sizes contributing to longer times to match.Clinical Relevance:This work associated donor and patient mismatches with longer wait times. This can be useful for patient counseling as well as provide a framework to determine whether there are solutions within the current meniscus donor pool that can be used to meet this clinical need.

Lateral patellar inclination (LPI) measures patellar tilt and is historically described on axial X-ray or a single magnetic resonance image (MRI). Given the variability in patellar height, LPI may be better represented by performing this measurement on two separate axial MRI images. We hypothesized that a two-image LPI measurement would be different from the current single-image LPI and have similar, if not superior reliability. Sixty-five patients treated for patellar instability (PI) between 2014 and 2017 were identified. Single image and two-image LPI were measured on axial MRI images. All measurements were performed by two independent observers. Reliability analysis was based on three observers' measurements of 30 randomly selected patients. Both the one image and two image LPI showed good inter-rater reliability (intraclass correlation coefficient [ICC] = 0.71 and 0.89, respectively), although the two image LPI had less variability. Both single image and two image LPI had near perfect intra-rater reliability (ICC = 0.98 and 0.98, respectively). Average single image LPI (14.6 +/- 9.9 degrees) was 6.1 +/- 3.4 degrees less than the average two image LPI (19.6 +/- 9.4 degrees) ( p = 0.037). Referencing a previously described 13.5 degrees maximum threshold, 54% of the patients had excessive patellar tilt based on single image LPI, while 73% had pathologic patellar tilt based on two image LPI. Two image LPI has similar reliability with less inter-rater variability compared with the historical single image LPI measurement. Significantly greater patellar tilt was identified with two image LPI that was found with single image LPI. A larger percentage of patients were classified as having pathologic patellar tilt based on two image LPI than single image LPI. The two image LPI provides more consistent and representative measurements of patellar tilt. Previously described threshold values for patellar tilt should be re-examined using this new measurement technique to appropriately risk stratify patients with PI and patellofemoral pain.

PURPOSE:Bone tunnel widening (TW) is a well-described complication after anterior cruciate ligament reconstruction (ACLR). The purpose of this study was to evaluate radiographic bone TW and clinical outcomes in patients with ACLR performed with suspensory fixation on both the femoral and tibial tunnels using different soft tissue grafts.METHODS:Patients who underwent primary ACLR with a soft tissue graft (hamstring autograft or allograft or quadriceps autograft) using an all-inside technique were included for analysis. Anterior cruciate ligament tunnel width was measured postoperatively on anteroposterior and lateral plain radiographs at a minimum of 12 months of follow-up. Clinical outcomes were assessed using the International Knee Documentation Committee (IKDC) subjective knee form as well as assessing patient records for complication data.RESULTS:Fifty patients (15 quadriceps autografts, 24 hamstring autografts, 11 hamstring allografts) were included in this study. The quadriceps autograft cohort was the youngest, (16.6 ± 2.8 years), followed by the hamstring autograft cohort (27.7 ± 9.0 years), and the hamstring allograft cohort (48.2 ± 9.4 years; p < 0.001) for all comparisons. Quadriceps autografts experienced less tibial tunnel-widening (0.6 ± 0.6 mm) than hamstring autografts (2.0 ± 1.1 mm; p = 0.011), which, in turn, experienced less widening than hamstring allografts (3.9 ± 2.3 mm; p < 0.001). Quadriceps autografts also experienced less femoral tunnel widening (0.3 ± 0.6 mm) than hamstring autografts (2.1 ± 1.2 mm; p < 0.001) which, in turn, experienced less tunnel-widening than hamstring allografts (4.0 ± 2.1; p < 0.001). At follow-up, mean IKDC for hamstring autografts, quadriceps autografts, and hamstring allografts were 79.9 ± 17.9, 88.5 ± 7.1, and 77.7 ± 20.4, respectively (p = 0.243). There was no statistically significant difference between groups with respect to postoperative complications; p = 0.874.CONCLUSIONS:Anterior cruciate ligament reconstruction with quadriceps autograft resulted in the least tunnel widening compared to hamstring autograft and allograft when using an all-inside suspensory fixation device. Both autograft groups resulted in less widening than the allograft group. Despite the greatest increased radiographic tunnel widening in the allograft group, there was no significant difference in clinical outcomes or knee laxity.

Discoid lateral meniscus (DLM) is a well-known meniscus variant, and comprises excess and thickened meniscal tissue, altered collagen ultrastructure, and peripheral instability. This article presents a comprehensive review on current knowledge of DLM, focusing on pathology in parallel with surgical techniques and outcomes. A paradigm shift in surgical management of DLM is taking place as knee surgeons are seeing more patients with long-term sequelae of partial lateral meniscectomy, the standard treatment for DLM for many years. Surgical treatment has evolved alongside the understanding of DLM pathology. A new classification system has been proposed and optimal surgical techniques described in recent years. This article highlights up-to-date evidence and techniques in management of both acute DLM tears and joint restoration following subtotal meniscectomy for DLM. Surgical management of DLM must be tailored to individual pathology, which is variable within the diagnosis of DLM. We present an algorithm for management of DLM and discuss future directions for the understanding and treatment of this debilitating condition.

Background: Blood flow restriction training (BFRT) after anterior cruciate ligament reconstruction (ACLR) is rising in popularity because of its benefits in reducing muscle atrophy and mitigating knee strength deficits. Purpose: To investigate the impact BFRT has on adolescent knee strength after ACLR at 2 postoperative time points: at 3 months and the time of return to sport (RTS). Study Design: Cohort study; Level of evidence, 3. Methods: A prospective intervention (BFRT) group was compared to an age-, sex-, and body mass index–matched retrospective control group. Patients aged 12 to 18 years who underwent primary ACLR with a quadriceps tendon autograft were included. Along with a traditional rehabilitation protocol, the BFRT group completed a standardized BFRT protocol (3 BFRT exercises performed twice weekly for the initial 12 weeks postoperatively). Peak torque values for isometric knee extension and flexion strength (at 3 months and RTS) and isokinetic strength at 180 deg/s (at RTS) as well as Pediatric International Knee Documentation Committee (Pedi-IKDC) scores were collected. Differences between the BFRT and control groups were compared with 2-way mixed analysis of variance and 1-way analysis of variance. Results: The BFRT group consisted of 16 patients (10 female; mean age, 14.84 ± 1.6 years) who were matched to 16 patients in the control group (10 female; mean age, 15.35 ± 1.3 years). Regardless of the time point, the BFRT group demonstrated significantly higher isometric knee extension torque compared to the control group (2.15 ± 0.12 N·m/kg [95% CI, 1.90-2.39] vs 1.74 ± 0.12 N·m/kg [95% CI, 1.49-1.98], respectively; mean difference, 0.403 N·m/kg; P = .024). The BFRT group also reported significantly better Pedi-IKDC scores compared to the control group at both 3 months (68.91 ± 9.68 vs 66.39 ± 12.18, respectively) and RTS (89.42 ± 7.94 vs 72.79 ± 22.81, respectively) ( P = .047). Conclusion: In adolescents, the addition of a standardized BFRT protocol to a traditional rehabilitation protocol after ACLR significantly improved knee strength and patient-reported function compared to a traditional rehabilitation program alone.