Previous Anterior Cruciate Ligament Research Articles

Bone Tunnel Enlargement after ACL Reconstruction with Hamstring Autograft Is Dependent on Original Bone Tunnel Diameter.

Background Bone tunnel enlargement is a well-established phenomenon following anterior cruciate ligament (ACL) reconstruction, and is related to soft tissue grafts, suspension fixation devices, and absorbable implants. Severe tunnel enlargement can lead to reconstruction failure. The correlation between bone tunnel enlargement following ACL reconstruction and original bone tunnel diameter has not been elucidated. Purpose To determine whether bone tunnel enlargement after ACL reconstruction with hamstring autograft is dependent on original tunnel diameter established during primary ACL reconstruction. Materials and Methods A retrospective review was conducted on 56 patients scheduled for ACL revision surgery who had undergone computed tomography (CT) scanning as part of their preoperative evaluation. All patients had undergone previous hamstring ACL reconstruction. Original femoral and tibial bone tunnel diameters were extracted from operative reports, and femoral and tibial bone tunnel enlargement was assessed on CT serial sections. The correlation between original tunnel diameter and bone tunnel enlargement was investigated using regression analysis. Results Mean tibial bone tunnel enlargement was significantly and inversely dependent on the original tibial bone tunnel diameter with a correlation coefficient of −0.55 per unit (7 mm = +1.93 mm, 8 mm = +1.43 mm, 9 mm = 0.83 mm, p = 0.007). Thus, every additional increase (mm) in diameter of the original tibial bone tunnel reduces the extend of tunnel widening by 0.55 mm. Conclusions The results of this study indicate that tibial bone tunnel enlargement following ACL reconstruction is dependent on original tibial bone tunnel diameter with smaller diameter tunnels developing more tunnel enlargement than larger tunnels. The contributing factors remain unclear and need to be further investigated.

Knee Osteoarthritis Is Associated With Previous Meniscus and Anterior Cruciate Ligament Surgery Among Elite College American Football Athletes.

Background:Football puts athletes at risk for knee injuries such meniscus and anterior cruciate ligament (ACL) tears, which are associated with the development of osteoarthritis (OA). Previous knee surgery, player position, and body mass index (BMI) may be associated with knee OA.Hypothesis:In elite football players undergoing knee magnetic resonance imaging at the National Football League’s Invitational Combine, the prevalence of knee OA is associated with previous knee surgery and BMI.Study Design:Retrospective cohort.Level of Evidence:Level 4.Methods:A retrospective review was performed of all participants of the National Football League Combine from 2005 to 2009 who underwent magnetic resonance imaging of the knee because of prior knee injury, surgery, or knee-related symptoms or concerning examination findings. Imaging studies were reviewed for evidence of OA. History of previous knee surgery—including ACL reconstruction, meniscal procedures, and articular cartilage surgery—and position were recorded for each athlete. BMI was calculated based on height and weight.Results:There was a higher prevalence of OA in knees with a history of previous knee surgery (23% vs 4.0%, P < 0.001). The prevalence of knee OA was 4.0% in those without previous knee surgery, 11% in those with a history of meniscus repair, 24% of those with a history of ACL reconstruction, and 27% of those with a history of partial meniscectomy. Among knees with a previous ACL reconstruction, the rate of OA doubled in tibiofemoral compartments in which meniscal surgery was performed. BMI >30 kg/m2 was also associated with a higher risk of OA (P = 0.007) but player position was not associated with knee OA.Conclusions:Previous knee surgery, particularly ACL reconstruction and partial meniscectomy, and elevated BMI are associated with knee OA in elite football players. Future research should investigate ways to minimize the risk of OA after knee surgery in these athletes.Clinical Relevance:Treatment of knee injuries in football athletes should consider chondroprotection, including meniscal preservation and cartilage repair, when possible.

Arthroscopic refixation of acute proximal anterior cruciate ligament rupture using suture anchors

Arthroscopic assisted suture anchor refixation combined with microfracturing of the femoral ACL insertion zone in cases of acute proximal anterior cruciate ligament (ACL) rupture to restore anatomical and biomechanical properties of the native ACL. Acute proximal ACL rupture/avulsion, multiligament injury of the knee CONTRAINDICATIONS: Chronic (>6weeks) proximal ACL rupture, intraligamentary rupture, as well as previous ACL surgery. Arthroscopic examination of the knee joint, debridement of the femoral insertion zone, examination of the ligament quality by aprobe, insertion of acurved lasso through the ACL to place the sutures and use of adrill guide to place the anchor in the middle of the femoral ACL insertion. Microfracturing holes around the femoral footprint were made by an awl to enhance healing properties of the ACL. Partial weight bearing was permitted and crutches were used for 6weeks, knee brace limited for the first 2weeks 0‑0-0°, then 0‑0-90° for the following 4weeks. Atotal of 20patients who underwent acute proximal ACL suture anchor refixation were evaluated after amean follow-up of 28months. Regarding stability, mean values of the KT-1000 arthrometer indicated stable results (<3mm), 3patients had a1+ Lachman and 4patients had a1+ pivot shift. IKDC (International Knee Documentation Committee) score indicated that 17 cases were very good to good (12A, 4B) and in 3 cases the results were satisfactory (3C). Magnetic resonance imaging showed that the ALC was found to be intact in 17cases. The total rate of revision was 15 % (3/20) because of recurrent instability.

Relationship Between Posterior-Inferior Tibial Slope and Bilateral Noncontact ACL Injury.

Is there a correlation between increased posterior-inferior tibial slope angle and noncontact anterior cruciate ligament (ACL) injury? Does increasing the posterior-inferior tibial slope angle increase the risk of bilateral ACL injury? A computerized relational database (Access 2007; Microsoft Inc, Redmond, Washington) was used to conduct a retrospective review of patients undergoing bilateral or unilateral ACL reconstruction surgery or treatment by a single surgeon between 1995 and 2013. Included in the study were patients with bilateral and unilateral ACL injuries and patellofemoral pain syndrome with no associated ACL deficiency. Exclusion criteria included concomitant ligament injury, previous ACL reconstruction, and previous knee surgery. Also excluded were patients who did not have plain lateral radiographs. Fifty patients were randomly selected from each group. After controlling for age and Tegner activity level, the authors found that the posterior-inferior tibial slope angle was a significant predictor (P=.002) of noncontact ACL injury. Mean posterior-inferior tibial slope angle for the bilateral, unilateral, and control groups was 11.8°±2.3°, 9.3°±2.4°, and 7.5°±2.3°, respectively. In the group with unilateral ACL injury vs the group without ACL deficiency, a 1° increase in posterior-inferior tibial slope angle (P=.03) was associated with a 20% increase in unilateral ACL injury. In those with bilateral ACL injury vs those without ACL deficiency, a 1° increase in posterior-inferior tibial slope angle (P=.001) increased bilateral knee injury by 34%. The difference between the mean angles of the control group without ACL deficiency and both the bilateral injury and unilateral injury cohorts was statistically significant (P=.003). Increased posterior-inferior tibial slope angle is associated with an increased risk of noncontact bilateral and unilateral ACL injury. [Orthopedics. 2017; 40(1):e136-e140.].

Comparison of Gait Characteristics Between Patients With Nontraumatic and Posttraumatic Medial Knee Osteoarthritis

To compare knee kinematics and kinetics during walking in patients with posttraumatic versus nontraumatic medial compartment knee osteoarthritis (OA). Participants with medial compartment knee OA were classified as nontraumatic (n = 122) or posttraumatic (n = 93) based on evidence of previous anterior cruciate ligament tear, confirmed arthroscopically. Kellgren/Lawrence severity scores and mechanical axis angle (MAA) were determined from radiographs. Knee flexion and adduction angles and external moments were calculated from gait analysis using a 3-dimensional optical motion capture system and force plate. Peak values were identified and principal component (PC) analysis determined waveform characteristics (PC scores). Linear regression models examined whether the OA group (posttraumatic or nontraumatic) predicted peak values and PC scores after controlling for age, gait speed, and severity. Models were repeated with and without controlling for MAA. The knee OA group was a significant predictor of peak knee adduction angles (P = 0.04) and moments (P = 0.05). Similarly, it was a significant predictor for some knee adduction angle (P = 0.02 to 0.64) and moment (P = 0.02 to 0.25) PC scores. The nontraumatic OA group had higher adduction angles and moments. There were no significant relationships between OA group and knee flexion angles and moments. After controlling for MAA, only one significant relationship remained between knee adduction moment shape characteristics and OA group. Frontal plane knee kinematics and kinetics during walking differ between patients with posttraumatic versus nontraumatic medial compartment knee OA, with posttraumatic OA showing relatively decreased adduction.

Risk Factors for Radiographic Progression of Osteoarthritis After Meniscus Allograft Transplantation

To identify risk factors that predict radiographic progression of osteoarthritis after meniscus allograft transplantation (MAT) using multivariate logistic regression. Inclusion criteria were consecutive patients who underwent medial or lateral MATs from January 2005 to September 2012 by one surgeon. Exclusion criteria were lack of postoperative magnetic resonance image, loss to follow-up for a minimum of 3years, and simultaneous surgery on articular cartilage or the anterior cruciate ligament. According to the change of Kellgren-Lawrence (KL) grade at the mean final follow-up of 56.2months, the enrolled MATs were sorted into the no progression of osteoarthritis (NOA) and progression of osteoarthritis (POA) groups. Multivariate logistic regression was used to analyze risk factors, including age, sex, body mass index, time from previous meniscectomy to MAT, extent of previous meniscectomy, previous anterior cruciate ligament reconstruction, knee alignment angle, KL grade, side of transplanted meniscus, Outerbridge grade, posterior repair technique, and relative percentage of extrusion. In comparison between the NOA (n= 38) and the POA (n= 31) groups, a significant risk factor for radiographic progression of osteoarthritis after MAT was medial MAT compared with lateral MAT. Medial MAT compared with lateral MAT was also a significant risk factor (adjusted odds ratio, 3.763; 95% confidence interval, 1.212-11.683). Patients need to be counseled about the increased risk of osteoarthritis progression after MAT over time, particularly for medial MAT. Level III, retrospective case control study.

Meniscal and Articular Cartilage Predictors of Clinical Outcome After Revision Anterior Cruciate Ligament Reconstruction

Background: Revision anterior cruciate ligament (ACL) reconstruction has been documented to have worse outcomes compared with primary ACL reconstructions. Purpose/Hypothesis: The purpose of this study was to determine if the prevalence, location, and/or degree of meniscal and chondral damage noted at the time of revision ACL reconstruction predicts activity level, sports function, and osteoarthritis symptoms at 2-year follow-up. The hypothesis was that meniscal loss and high-grade chondral damage noted at the time of revision ACL reconstruction will result in lower activity levels, decreased sports participation, more pain, more stiffness, and more functional limitation at 2 years after revision surgery. Study Design: Cohort study; Level of evidence, 2. Methods: Between 2006 and 2011, a total of 1205 patients who underwent revision ACL reconstruction by 83 surgeons at 52 hospitals were accumulated for study of the relationship of meniscal and articular cartilage damage to outcome. Baseline demographic and intraoperative data, including the International Knee Documentation Committee (IKDC) subjective knee evaluation, Knee injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Marx activity score, were collected initially and at 2-year follow-up to test the hypothesis. Regression analysis was used to control for age, sex, body mass index, smoking status, activity level, baseline outcome scores, revision number, time since last ACL reconstruction, incidence of having a previous ACL reconstruction on the contralateral knee, previous and current meniscal and articular cartilage injury, graft choice, and surgeon years of experience to assess the meniscal and articular cartilage risk factors for clinical outcomes 2 years after revision ACL reconstruction. Results: At 2-year follow-up, 82% (989/1205) of the patients returned their questionnaires. It was found that previous meniscal injury and current articular cartilage damage were associated with the poorest outcomes, with prior lateral meniscectomy and current grade 3 to 4 trochlear articular cartilage changes having the worst outcome scores. Activity levels at 2 years were not affected by meniscal or articular cartilage pathologic changes. Conclusion: Prior lateral meniscectomy and current grade 3 to 4 changes of the trochlea were associated with worse outcomes in terms of decreased sports participation, more pain, more stiffness, and more functional limitation at 2 years after revision surgery, but they had no effect on activity levels. Registration: NCT00625885

Extra-articular procedures for the ACL-deficient knee: a state of the art review

Some patients have continued rotatory instability following intra-articular anterior cruciate ligament (ACL) reconstruction, which limits their functional abilities. Advanced surgical techniques, such as double-bundle reconstruction and anteromedial portal drilling, have not solved this problem. This has led many surgeons to revisit the use of extra-articular procedures to control rotatory laxity. Multiple anatomic studies have confirmed the presence of an anterolateral ligament (ALL) that attaches to the tibia at the site of the Segond fracture. The biomechanical importance of this ligament is still being debated. Extra-articular reconstructions decrease the forces produced by intra-articular ACL grafts. Patients likely to benefit from additional extra-articular reconstruction are: (1) those with high-grade pivot shifts; (2) patients with previous failed ACL reconstructions without an obvious cause; (3) participants in contact sports and (4) patients in subgroups that have a high risk of failure (eg, generalised laxity). A variety of extra-articular reconstructions have been developed. Those techniques that have long-term follow-up data were described before most current orthopaedic surgeons were in practice. The available evidence suggests that performing an additional extra-articular reconstruction can improve rotational stability in patients undergoing intra-articular ACL reconstructions. Newer ‘anatomic’ reconstructions of the ALL have recently been proposed but there are limited data on their effectiveness. Currently, there are no studies comparing different extra-articular procedures.

Athletic Performance at the National Basketball Association Combine After Anterior Cruciate Ligament Reconstruction.

Background:Anterior cruciate ligament (ACL) injuries are significant injuries in elite-level basketball players. In-game statistical performance after ACL reconstruction has been demonstrated; however, few studies have reviewed functional performance in National Basketball Association (NBA)–caliber athletes after ACL reconstruction.Purpose:To compare NBA Combine performance of athletes after ACL reconstruction with an age-, size-, and position-matched control group of players with no previous reported knee injury requiring surgery. We hypothesized that there is no difference between the 2 groups in functional performance.Study Design:Cross-sectional study; Level of evidence, 3.Methods:A total of 1092 NBA-caliber players who participated in the NBA Combine between 2000 and 2015 were reviewed. Twenty-one athletes were identified as having primary ACL reconstruction prior to participation in the combine. This study group was compared with an age-, size-, and position-matched control group in objective functional performance testing, including the shuttle run test, lane agility test, three-quarter court sprint, vertical jump (no step), and maximum vertical jump (running start).Results:With regard to quickness and agility, both ACL-reconstructed athletes and controls scored an average of 11.5 seconds in the lane agility test and 3.1 seconds in the shuttle run test (P = .745 and .346, respectively). Speed and acceleration was measured by the three-quarter court sprint, in which both the study group and the control group averaged 3.3 seconds (P = .516). In the maximum vertical jump, which demonstrates an athlete’s jumping ability with a running start, the ACL reconstruction group had an average height of 33.6 inches while the controls averaged 33.9 inches (P = .548). In the standing vertical jump, the ACL reconstruction group averaged 28.2 inches while the control group averaged 29.2 inches (P = .067).Conclusion:In athletes who are able to return to sport and compete at a high level such as the NBA Combine, there is no significant difference in any combine performance test between players who have had primary ACL reconstruction compared with an age-, size-, and position-matched control group.Clinical Relevance:Athletes with previous ACL reconstruction who are able to return to high-level professional basketball have equivalent performance measures with regard to speed, quickness, and jumping ability as those athletes who have not undergone knee surgery.

Multivariate Analysis of Risk Factors of Graft Extrusion After Lateral Meniscus Allograft Transplantation

To identify risk factors that predict major graft extrusion (>3 mm in relation to the margin of the tibial plateau) on magnetic resonance imaging (MRI) after lateral meniscus allograft transplantation (MAT) using multivariate logistic regression. In this retrospective trial, inclusion criteria were consecutive lateral MATs from January 2004 to June 2013. Exclusion criteria were the lack of postoperative MRI, loss to follow-up for minimum 2 years, and simultaneous surgery of the articular cartilage or anterior cruciate ligament. According to the measured extent of graft extrusion in postoperative MRI, the lateral MATs were sorted into minor extrusion and major extrusion groups. Multivariate logistic regression was used to analyze risk factors including age, gender, body mass index, time from previous meniscectomy to MAT, extent of previous meniscectomy, previous anterior cruciate ligament reconstruction, knee alignment angle, Kellgren-Lawrence grade, lateral peripheral osteophyte, Outerbridge grade, posterior repair technique the position of bony bridge, and axial plane trough angle. Enrolled 72 lateral MATs were sorted into minor extrusion (n= 34) and major extrusion groups (n= 38). As time from previous meniscectomy to lateral MAT increased, the risk of the major graft extrusion after lateral MAT increased (adjusted odds ratio: 1.554, 95% confidence interval: 1.089 to 2.218). Increased axial plane trough angle was also a significant risk factor (adjusted odds ratio: 8.449, 95% confidence interval: 1.710 to 42.250). The other parameters were not significant risk factors. Most meniscal grafts after lateral MATs showed major graft extrusion. Significant risk factors for the major graft extrusion included delayed time from previous meniscectomy to MAT and increased axial plane trough angle. Level III, retrospective comparative study.

Biceps Femoris Architecture and Strength in Athletes with a Previous Anterior Cruciate Ligament Reconstruction.

This study aimed to determine whether limbs with a history of anterior cruciate ligament (ACL) injury reconstructed from the semitendinosus display different biceps femoris long head (BFlh) architecture and eccentric strength, assessed during the Nordic hamstring exercise, compared with the contralateral uninjured limb. The architectural characteristics of the BFlh were assessed at rest and at 25% of a maximal voluntary isometric contraction (MVIC) in the control group (n = 52) and in the group who had previous ACL injury (n = 15) using two-dimensional ultrasonography. Eccentric knee flexor strength was assessed during the Nordic hamstring exercise. Fascicle length was shorter (P = 0.001; d range, 0.90-1.31) and pennation angle (P range, 0.001-0.006; d range, 0.87-0.93) was greater in the BFlh of the ACL-injured limb compared with those in the contralateral uninjured limb at rest and during a 25% MVIC. Eccentric strength was lower in the ACL-injured limb when compared with the contralateral uninjured limb. Fascicle length, MVIC, and eccentric strength were not different between the left and right limb in the control group. Limbs with a history of ACL injury reconstructed from the semitendinosus have shorter fascicles and greater pennation angles in the BFlh compared with those of the contralateral uninjured side. Eccentric strength during the Nordic hamstring exercise of the ACL-injured limb is significantly lower than that of the contralateral side. These findings have implications for ACL rehabilitation and hamstring injury prevention practices, which should consider altered architectural characteristics.

Anterior Cruciate Ligament Injuries in National Football League Athletes From 2010 to 2013: A Descriptive Epidemiology Study.

Background:There is a high incidence of anterior cruciate ligament (ACL) injuries among National Football League (NFL) athletes; however, the incidence of reinjury in this population is unknown.Purpose:This retrospective epidemiological study analyzed all publicly disclosed ACL tears occurring in NFL players between 2010 and 2013 to characterize injury trends and determine the incidence of reinjury.Study Design:Descriptive epidemiological study.Methods:A comprehensive online search identified any NFL player who had suffered an ACL injury from 2010 to 2013. Position, playing surface, activity, and date were recorded. Each player was researched for any history of previous ACL injury. The NFL games database from USA Today was used to determine the incidence of ACL injuries on artificial turf and grass fields. Databases from Pro Football Focus and Pro Football Reference were used to determine the injury rate for each position.Results:NFL players suffered 219 ACL injuries between 2010 and 2013. Forty players (18.3%) had a history of previous ACL injury, with 27 (12.3%) retears and 16 (7.3%) tears contralateral to a previous ACL injury. Five players (2.28%) suffered their third ACL tear. Receivers (wide receivers and tight ends) and backs (linebackers, fullbacks, and halfbacks) had significantly greater injury risk than the rest of the NFL players, while perimeter linemen (defensive ends and offensive tackles) had significantly lower injury risk than the rest of the players. Interior linemen (offensive guards, centers, and defensive tackles) had significantly greater injury risk compared with perimeter linemen. ACL injury rates per team games played were 0.050 for grass and 0.053 for turf fields (P > .05).Conclusion:In this retrospective epidemiological study of ACL tears in NFL players, retears and ACL tears contralateral to a previously torn ACL constituted a substantial portion (18.3%) of total ACL injuries. The significant majority of ACL injuries in players with a history of previous ACL injury were retears. Skilled offensive players and linebackers had the greatest injury risk, and significantly more ACL tears occurred among interior linemen than perimeter linemen. The month of August had the highest incidence of ACL injuries, probably because of expanded roster sizes at that point in the NFL season.

The Vertical Drop Jump Is a Poor Screening Test for ACL Injuries in Female Elite Soccer and Handball Players

Background: The evidence linking knee kinematics and kinetics during a vertical drop jump (VDJ) to anterior cruciate ligament (ACL) injury risk is restricted to a single small sample. Still, the VDJ test continues to be advocated for clinical screening purposes. Purpose: To test whether 5 selected kinematic and kinetic variables were associated with future ACL injuries in a large cohort of Norwegian female elite soccer and handball players. Furthermore, we wanted to assess whether the VDJ test can be recommended as a screening test to identify players with increased risk. Study Design: Cohort study; Level of evidence, 2. Methods: Elite female soccer and handball players participated in preseason screening tests from 2007 through 2014. The tests included marker-based 3-dimensional motion analysis of a drop-jump landing. We followed a predefined statistical protocol in which we included the following candidate risk factors in 5 separate logistic regression analyses, with new ACL injury as the outcome: (1) knee valgus angle at initial contact, (2) peak knee abduction moment, (3) peak knee flexion angle, (4) peak vertical ground-reaction force, and (5) medial knee displacement. Results: A total of 782 players were tested (age, 21 ± 4 years; height, 170 ± 7 cm; body mass, 67 ± 8 kg), of which 710 were included in the analyses. We registered 42 new noncontact ACL injuries, including 12 in previously ACL-injured players. Previous ACL injury (relative risk, 3.8; 95% CI, 2.1-7.1) and medial knee displacement (odds ratio, 1.40; 95% CI, 1.12-1.74 per 1-SD change) were associated with increased risk for injury. However, among the 643 players without previous injury, we found no association with medial knee displacement. A receiver operating characteristic curve analysis of medial knee displacement showed an area under the curve of 0.6, indicating a poor-to-failed combined sensitivity and specificity of the test, even when including previously injured players. Conclusion: Of the 5 risk factors considered, medial knee displacement was the only factor associated with increased risk for ACL. However, receiver operating characteristic curve analysis indicated a poor combined sensitivity and specificity when medial knee displacement was used as a screening test for predicting ACL injury. For players with no previous injury, none of the VDJ variables were associated with increased injury risk. Clinical Relevance: VDJ tests cannot predict ACL injuries in female elite soccer and handball players.

Rates and Determinants of Return to Play After Anterior Cruciate Ligament Reconstruction in National Collegiate Athletic Association Division I Soccer Athletes

Background: Factors and details regarding return to play in elite, collegiate female soccer athletes after an anterior cruciate ligament (ACL) injury and reconstruction have not been well studied. Purpose: To evaluate return to play among collegiate female soccer players, specifically examining the effect of surgical and individual athlete characteristics on the return-to-play rate. Study Design: Descriptive epidemiology study. Methods: Sports medicine and athletic training staff at institutions from the National Collegiate Athletic Association Southeastern Conference (SEC) were contacted to request participation in the study. All institutions were sent a standardized spreadsheet with response choices and instructions regarding athlete inclusion criteria. Athlete, injury, surgical technique, and return-to-play data were requested for ACL reconstructions performed on female soccer athletes at the participating institutions over the previous 8 years. χ2 analyses were used to compare the return-to-play rate by year in school, scholarship status, position, depth chart status, procedure, graft type, graft fixation, concomitant procedures, and previous ACL injuries. Results: All 14 of the SEC institutions chose to participate and provided data. A total of 80 ACL injuries were reported, with 79 surgical reconstructions and return-to-play data for 78 collegiate soccer athletes. The overall return-to-play rate was 85%. There was a statistical significance in return-to-play rates favoring athletes in earlier years of eligibility versus later years (P < .001). Athletes in eligibility years 4 and 5 combined had a return-to-play rate of only 40%. Scholarship status likewise showed significance (P < .001), demonstrating a higher return-to-play rate for scholarship athletes (91%) versus nonscholarship athletes (46%). No significant differences in return-to-play rates were observed based on surgical factors, including concomitant knee procedures, graft type, and graft fixation method. Conclusion: Collegiate female soccer athletes have a high initial return-to-play rate. Undergoing ACL reconstruction earlier in the college career as well as the presence of a scholarship had a positive effect on return to play. Surgical factors including graft type, fixation method, tunnel placement technique, concomitant knee surgeries, and revision status demonstrated no significant effect on the return-to-play rate.

Eccentric Knee Flexor Strength and Risk of Hamstring Injuries in Rugby Union

Background: Hamstring strain injuries (HSIs) represent the most common cause of lost playing time in rugby union. Eccentric knee flexor weakness and between-limb imbalance in eccentric knee flexor strength are associated with a heightened risk of HSIs in other sports; however, these variables have not been explored in rugby union. Purpose: To determine if lower levels of eccentric knee flexor strength or greater between-limb imbalance in this parameter during the Nordic hamstring exercise are risk factors for HSIs in rugby union. Study Design: Cohort study; Level of evidence, 2. Methods: This prospective study was conducted over the 2014 Super Rugby and Queensland Rugby Union seasons. In total, 178 rugby union players (mean age, 22.6 ± 3.8 years; mean height, 185.0 ± 6.8 cm; mean weight, 96.5 ± 13.1 kg) had their eccentric knee flexor strength assessed using a custom-made device during the preseason. Reports of previous hamstring, quadriceps, groin, calf, and anterior cruciate ligament injuries were also obtained. The main outcome measure was the prospective occurrence of HSIs. Results: Twenty players suffered at least 1 HSI during the study period. Players with a history of HSIs had a 4.1-fold (95% CI, 1.9-8.9; P = .001) greater risk of subsequent HSIs than players without such a history. Between-limb imbalance in eccentric knee flexor strength of ≥15% and ≥20% increased the risk of HSIs by 2.4-fold (95% CI, 1.1-5.5; P = .033) and 3.4-fold (95% CI, 1.5-7.6; P = .003), respectively. Lower eccentric knee flexor strength and other prior injuries were not associated with an increased risk of future HSIs. Multivariate logistic regression revealed that the risk of reinjuries was augmented in players with strength imbalances. Conclusion: Previous HSIs and between-limb imbalance in eccentric knee flexor strength were associated with an increased risk of future HSIs in rugby union. These results support the rationale for reducing imbalance, particularly in players who have suffered a prior HSI, to mitigate the risk of future injuries.

A Modified Transtibial Technique Was Similar to an Anteromedial Portal Technique for Anterior Cruciate Ligament Reconstruction.

Youm YS, Cho SD, Lee SH, Youn CH. Modified Transtibial Versus Anteromedial Portal Technique in Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction: Comparison of Femoral Tunnel Position and Clinical Results. Am J Sports Med. 2014 Dec;42(12):2941-7. ### Question: In patients having single-bundle anterior cruciate ligament (ACL) reconstruction, how does a modified transtibial technique compare with an anteromedial portal technique for femoral tunnel positioning? ### Design: Randomized (allocation concealed), blinded (patients and outcome assessor), controlled trial with a mean follow-up of 24 months. ### Setting: A university hospital in Ulsan, Korea. ### Patients: 40 patients (mean age, 29 years; 98% men) who were undergoing anatomic single-bundle ACL reconstruction with fresh-frozen Achilles tendon allograft. Exclusion criteria were previous ACL reconstruction, posterior cruciate ligament ruptures or posterolateral rotatory instability, or fractures around the knee joint. All patients completed follow-up. ### Intervention: Patients were allocated to reconstruction with the modified transtibial technique (n = 20) or the anteromedial portal technique (n = 20). For the modified transtibial technique, the knee was flexed to 80°. For the anteromedial portal technique, the knee was fully flexed. The procedures were otherwise the same. ### Main outcome measures: Subjective evaluations were the 2000 International Knee Documentation Committee (IKDC) subjective knee score, the Lysholm knee score, and the Tegner activity …

Knee joint subchondral bone structure alterations in active athletes: a cross-sectional case–control study

It has been shown that trabecular bone structure parameters extracted from radiographs known as fractal signature analysis (FSA) are able to predict structural outcomes such as radiographic osteoarthritis (OA) progression. Little is known about their involvement in early disease or about differences between subjects exposed to increased joint loading such as young active athletes compared to non-athletes. Aim was to compare horizontal and vertical dimensions of bone texture considering athlete status, gender, previous anterior cruciate ligament (ACL) surgery and age. Included were 685 patients of which 135 consecutive athletes (82% soccer players) 18-36 years old and 550 non-athletes controls in the same age range had knee radiography for assessment of subacute or chronic knee complaints. Regions of interest (ROI) were placed in the subchondral medial and lateral tibial plateaus. Fractal signatures were calculated in the horizontal and vertical dimensions. Curve fitting algorithms were applied taking into account all four risk factors in the same model adjusting for each other. For the horizontal dimensions significant differences were observed for gender (estimate (E) 0.098 (95% confidence interval(CI)) (-0.009, 0.008), P<.0001), previous ACL surgery (E-0.031, 95% CI (-0.043,-0.019), P<.0001) and highest age group (E-0.039, 95% CI (-0.048,-0.029), P<.0001). For vertical dimensions, significant differences were shown for athletes (E-0.012, 95% CI (-0.020,-0.004), P<.0001), gender (E 0.056, 95% CI (0.049, 0.062), P<.0001), and age range from 28 to 32 years (E-0.028, 95% CI (-0.037,-0.019), P<.0001). Trabecular bone structure differs between athletes and non-athletes, in regard to previous ACL surgery, gender and higher age.

Biomechanical jumping differences among elite female handball players with and without previous anterior cruciate ligament reconstruction: a novel inertial sensor unit study

Persistent biomechanical and jumping capacity alterations have been observed among female athletes who have sustained anterior cruciate ligament (ACL) injuries. The purpose of this study was to examine if biomechanical jumping differences persist among a cohort of elite female handball players with previous ACL reconstruction several years after return to top-level competition. In order to achieve this goal, a direct mechanics simplified analysis by using a single Inertial Sensor Unit (IU) was used. Twenty-one elite female (6 anterior cruciate ligament reconstructed and 15 uninjured control players) handball players were recruited and evaluated 6.0 ± 3.5 years after surgical anterior cruciate ligament reconstruction. Bilateral and unilateral vertical jumps were performed to evaluate the functional performance and a single inertial sensor unit was employed in order to collect 3D acceleration and 3D orientation data. Previously ACL-reconstructed analysed athletes demonstrated significant (p < 0.05) alterations in relation to the three-dimensional axis (X–Y–Z) supported accelerations and differing jump phase durations, including jumping performance values, in both bilateral and unilateral jumping manoeuvres several years after ACL reconstruction. Identification of the encountered deficits through the use of an IU devise could provide clinicians with a new reliable tool for movement analysis in a clinical setting.

Acceleration and Orientation Jumping Performance Differences Among Elite Professional Male Handball Players With or Without Previous ACL Reconstruction: An Inertial Sensor Unit-Based Study

BackgroundHandball is one of the most challenging sports for the knee joint. Persistent biomechanical and jumping capacity alterations can be observed in athletes with an anterior cruciate ligament (ACL) injury. Commonly identified jumping biomechanical alterations have been described by the use of laboratory technologies. However, portable and easy-to-handle technologies that enable an evaluation of jumping biomechanics at the training field are lacking. ObjectiveTo analyze unilateral/bilateral acceleration and orientation jumping performance differences among elite male handball athletes with or without previous ACL reconstruction via a single inertial sensor unit device. DesignCase control descriptive study. SettingAt the athletes' usual training court. ParticipantsTwenty-two elite male (6 ACL-reconstructed and 16 uninjured control players) handball players were evaluated. MethodsThe participants performed a vertical jump test battery that included a 50-cm vertical bilateral drop jump, a 20-cm vertical unilateral drop jump, and vertical unilateral countermovement jump maneuvers. Main outcome measurementsPeak 3-dimensional (X, Y, Z) acceleration (m·s−2), jump phase duration and 3-dimensional orientation values (°) were obtained from the inertial sensor unit device. Two-tailed t-tests and a one-way analysis of variance were performed to compare means. The P value cut-off for significance was set at P < .05. ResultsThe ACL-reconstructed male athletes did not show any significant (P < .05) residual jumping biomechanical deficits regarding the measured variables compared with players who had not suffered this knee injury. A dominance effect was observed among non-ACL reconstructed controls but not among their ACL-reconstructed counterparts (P < .05). ConclusionsElite male handball athletes with previous ACL reconstruction demonstrated a jumping biomechanical profile similar to control players, including similar jumping performance values in both bilateral and unilateral jumping maneuvers, several years after ACL reconstruction. These findings are in agreement with previous research showing full functional restoration of abilities in top-level male athletes after ACL reconstruction, rehabilitation and subsequent return to sports at the previous level.

Previous Anterior Cruciate Ligament Injury Compromises Bone and Muscle Strength in Collegiate Athletes

A growing body of research has shown that recreationally active individuals have decreased bone and muscle strength following anterior cruciate ligament (ACL) injury and reconstruction; largely attributed to immobility following reconstructive surgery. However, little research has examined musculoskeletal adaption to ACL injury among collegiate athletes. PURPOSE: To examine limb-to-limb differences in muscle and bone strength parameters in collegiate athletes with a history of ACL injury and reconstruction. METHODS: Peripheral quantitative computed tomography (pQCT) and a series of muscle function tests were used to assess bone and muscle strength, respectively, among 12 Division III college athletes (5 males, 7 females; age=20.7 ± 0.5 years) with an ACL injury in the previous five years. Total and cortical bone volumetric density (ToD and CoD), and cortical bone mineral content (CoCnt), bone area (CoA), thickness (CoTh) and estimated bone strength (SSIp), along with muscle cross-sectional area (MCSA) were measured using pQCT at the proximal tibia (66%), patella midline, and distal femur (20%) sites. Muscle function assessment included single-leg hop and isometric manual muscle tests. A Lysholm Knee Scoring Scale was also administered. Both limbs were measured and a leg symmetry index (LSI) was calculated for all assessments. RESULTS: Tibia CoCnt (LSI=97.3%) was lower in the injured limb, along with patella ToD (LSI=89.7%; both p<0.05). At the femur, CoA (LSI= 94.4%) and CoTh (LSI= 94.4%) were lower in the injured limb (both p<0.05). MCSA was lower at the tibia (LSI=96.2%) and femur (LSI= 87.1%) of the injured limb, along with performance on the single leg (LSI= 78.2%) and cross hop (LSI=85.3%) patterns of the hop test (all p<0.05). No limb differences were found for manual muscle tests. CONCLUSIONS: Our results showed less robust bone density and geometry parameters, along with lower muscle strength outcomes in ACL-injured limbs among collegiate athletes up to five years following injury. These differences, however, were less pronounced than deficits previously reported among older, recreational athletes. Future research should investigate the effect of pre-injury health and fitness status in athletes compared to the general population. Supported by University of St. Thomas Young Scholar Grant.