Effect of Graft Type on Thigh Circumference, Knee Range of Motion, and Lower-Extremity Strength in Pediatric and Adolescent Males Following Anterior Cruciate Ligament Reconstruction

in Journal of Sport Rehabilitation

Context: To treat anterior cruciate ligament (ACL) injury, ACL reconstruction (ACLR) surgery is currently a standard of the care. However, effect of graft type including bone–patellar tendon–bone (BTB), hamstring tendon, or iliotibial band (ITB) on thigh size, knee range of motion (ROM), and muscle strength are understudied. Objective: To compare postoperative thigh circumference, knee ROM, and hip and thigh muscle strength in adolescent males who underwent ACLR, based on the 3 different autograft types: BTB, hamstring (HS), and ITB. Setting: Biomechanical laboratory. Participants: Male ACLR patients who are younger than 22 years of age (total N = 164). Intervention: At 6- to 9-month postoperative visits, thigh circumference, knee ROM, and hip and thigh muscle strength were measured. Main Outcome Measures: Deficits of each variable between the uninvolved and ACLR limb were compared for pediatric and adolescent ACLR males in the BTB, HS, and ITB cohorts. Baseline characteristics, including physical demographics and meniscus tear status, were compared, and differences identified were treated as covariates and incorporated in analysis of covariance. Results: Data were from 164 adolescent male ACLR patients [mean age 15.7 (1.2) years]. There were no statistical differences in thigh circumference, knee ROM, hip abductor, and hip-extensor strength among the 3 autografts. However, patients with BTB demonstrated 12.2% deficits in quadriceps strength compared with 0.5% surplus in HS patients (P = .002) and 1.2% deficits in ITB patients (P = .03). Patients with HS showed 31.7% deficits in hamstring strength compared with 5.4% deficits in BTB (P = .001) and 7.7% deficits in ITB (P = .001) groups at 6- to 9-month postoperative visits. Conclusion: Adolescent male ACLR patients with BTB and HS autografts demonstrated significant deficits in quadriceps and hamstring strength, respectively, at 6 to 9 months postoperatively. Minimal lower-extremity strength deficits were demonstrated in pediatric male ACLR patients undergoing ITB harvest.

The incidence rate of anterior cruciate ligament (ACL) injuries among pediatric and adolescent athletes has continued to increase over the years.13 Currently, ACL reconstruction (ACLR) surgery remains the standard of care for young athletes seeking a return to cutting and pivoting sports activity.4 In the United States alone, ACLR surgeries have ranged from 80,000 to 350,000 cases annually,4,5 with associated medical costs estimated at $2 billion.6 Utilized criteria for success following ACLR surgery have ranged from absence of instability episodes, satisfactory return to sports status, the absence of knee joint effusion, quadriceps muscle strength symmetry, and “good-to-excellent” patient-reported functional outcome measure scores.7,8 One particularly controversial and understudied component of achieving such measures of success is the optimization of “return-to-play” criteria, as early graft failure represents a relatively common finding in younger ACLR populations.9 There are many variations in “return-to-play” tests, and commonly applied basic physical measurements include thigh circumference, knee range of motion (ROM), muscular strength, and hop tests.1016

However, deficits in these parameters have been shown to be prevalent for much longer following ACLR surgery than previously assumed.14,1719 Following ACLR surgery, knee ROM deficits are often reported2022 along with strength deficits in quadriceps and hamstring muscles.14,23 The quadriceps and hamstrings muscles represent the primary dynamic stabilizers of the knee joint. Anterior shear force generated during knee extension, as well as the contact phase of landing, is mainly determined by the quadriceps muscle action via the patella tendon-tibia shaft angle.24,25 During landing, the hamstrings, antagonists of the quadriceps, provide posterior shear forces on the tibia; thereby, counterbalancing the anterior shear force generated by the quadriceps and protecting the ACL from excessive loads. Thus, the specific balance between quadriceps and hamstrings strength is particularly important because the ACL bundle is under maximum tension in the final 30° of knee extension.26

The implications of graft type on thigh size, knee ROM, and muscle strength have not been well studied, particularly in comparative fashion in the pediatric and adolescent population. Bone–patellar tendon–bone (BTB) and hamstring (HS) autografts have emerged as the 2 primary graft types in young athletes at or near skeletal maturity undergoing ACLR.27 While various techniques are utilized, Micheli et al28 developed a combined intra-articular/extra-articular physeal-sparing procedure that utilizes the tendinous iliotibial band (ITB) autograft. The ITB autograft was tailored for children and adolescents with significant growth remaining, and the main objective of this physeal-sparing autograft technique is to stabilize the knee while protecting the continued growth of the physes of the distal femur and proximal tibia (Figure 1). This technique is primarily used for skeletally immature pediatric athletes with significant (>2 y) growth remaining.29,30 It is unknown if graft type positively or negatively influences thigh circumference, knee ROM, and muscle strength following ACLR, especially in skeletally immature youth.

Figure 1
Figure 1

—Illustration of physeal-sparing autograft technique.

Citation: Journal of Sport Rehabilitation 29, 5; 10.1123/jsr.2018-0272

Therefore, our purpose is to compare the thigh circumference, knee ROM, quadriceps, hamstrings, hip abductor, and hip-extensor strength at 6 to 9 months postoperatively in pediatric and adolescent patients who underwent ACLR utilizing BTB, HS, or ITB grafts. We hypothesized that there would be no difference in thigh circumference and knee ROM among these groups, but differences would exist in muscle strength. More specifically, muscle groups that were directly affected by the graft harvest, specifically quadriceps strength following BTB, hamstring strength following HS, and hip abductor strength following ITB, were hypothesized to demonstrate postoperative weakness that could persist beyond the 6- to 9-month follow-up mark.

Methods

Study Design

An institutional review board of the Boston Children’s Hospital approved the current study study protocol. A retrospective case-control study design was used. Thigh circumference, knee ROM, and quadriceps, hamstring, and hip abductor strength were measured at an institutional injury prevention center as a standardized feature of the 6-month post-ACLR follow-up regimen for all patients undergoing surgery by surgeon-investigators in the current study (Heyworth MD, Kramer MD, Kocher MD, MPH, and Micheli MD). A review of the patient’s electronic medical records allowed for collection of demographic information, such as height, weight, and age. Status of meniscus tear and duration from ACLR to testing were examined, documented, and analyzed.

Patient Selection

Inclusion criteria for the current study consisted of patients who were under 21 years of age (including 21 y), sustained an ACL injury, and underwent ACLR surgery from 2015 to 2017 at the study institution. Patients older than 22 years of age were excluded. Because there were extremely limited number of female patients who had an ACLR with BTB and ITB autografts, and past studies indicated sex differences in ACL mechanics and outcome,3137 only male patients were included in a current analysis. This approach helps eliminating the potential confounder of “sex” between comparative cohorts. Also, only primary ACLR patients were included, and revisions were excluded because using 2 different grafts on the same knee would confound the purpose of this study. After applying the exclusion criteria, there were a total of 164 patients who met the inclusion criteria.

Measurements

The following measurements were taken by 3 health-care practitioners (board-certified athletic trainers)

Thigh Circumference Measures

Patients were asked to be in supine position with the knee extended. Then, patients were asked to relax their lower-extremity muscles, and a tape measure was applied to the thigh at 10 cm from proximal patella bilaterally.15,38

Range of Motion Test

A goniometer was positioned lateral to the knee joint to measure passive knee extension and flexion ROMs. Pivot of the goniometer was placed at the joint line of the femur and tibia. For knee extension, patients were in the supine position, and a foam roller was located at distal lower leg. In this position, the knee joint was passively moved from flexion to extension (Figure 2A). For knee flexion, patients were assessed in a prone position. The knee joint was then passively moved from extension and flexion (Figure 2B).15,39,40

Figure 2
Figure 2

—Images of knee extension (A) and flexion (B) range of motion measurements.

Citation: Journal of Sport Rehabilitation 29, 5; 10.1123/jsr.2018-0272

Muscle Strength Test

Quadriceps strength was assessed while patients were seated on the edge of treatment table with 90° of knee flexion. Then, a handheld dynamometer (Hoggan Scientific LLC, Salt Lake City, UT) was applied to the anterior side of distal tibia above the dome of talus, and patients were asked to extend their knees with maximum effort. For hamstrings strength, patients were in a prone position with 90° of knee flexion. A handheld dynamometer was applied at posterior side (Achilles tendon side) of the distal tibia, and patients were asked to further flex their knees toward the hip with maximum effort. For hip abductor strength, patients were asked to lay down on the side, with the targeted leg was slightly pulled toward posterior and downward directions. A handheld dynamometer was applied right above of lateral malleolus, and patients were asked to move their legs toward the ceiling with maximum effort (direction of hip abduction). For hip-extensor strength, patients were in a prone position with 90° of knee flexion. A handheld dynamometer was applied at middle 1/3 of the posterior thigh (hamstrings side), and patients were asked to move the flexed legs toward ceiling.15,41 A handheld dynamometer was held by examiners, and a hold test method was used to measure the isometric strength. Duplicate measures (2 times per each muscle group) of the isometric strength were taken for each muscle group bilaterally. Mean values of 2 measurements from each muscle group were recorded, and data were normalized by body weight.

To ensure reliability of the 3 testers, the interrater reliability of the 3 raters was measured using intraclass correlation values. The intraclass correlation values of the 3 raters in thigh circumference, knee ROM, and muscular strength were 97.8% (95% confidence interval [CI], 83.0%–100.0%), 99.2% (95% CI, 90.0%–99.9%), 96.6% (95% CI, 88.6%–99.3%), respectively. The intrarater reliability was also measured using a combination of the 3 measures (thigh circumference, knee ROM, and muscular strength) and generated intraclass correlation values of: tester A: 90.8% (95% CI, 71.6%–97.0%), tester B: 98.9% (95% CI, 96.8%–99.7%), and tester C: 99.5% (95% CI, 98.5%–99.8%).

Statistical Analysis

Dependent variables analyzed included thigh circumference, knee ROM, and normalized quadriceps, hamstring, hip abductors, and hip-extensor strength. In order to identify asymmetry in thigh circumference, a lack of knee ROM, and weakness in lower-extremity strength, deficits (in percentage), which were calculated as [(ACLR limb)/(uninvolved limb) − 1], were used. Independent variables analyzed included autograft type (BTB, HS, and ITB). One-way analysis of variance was performed to examine the differences in patients’ characteristics, including demographics (age, height, weight, and body mass index [BMI]) and duration from ACLR to the physical measurements. Chi-square (χ2) was used to compare the status of meniscus tears among the 3 graft types. If any differences were detected, the variable was treated as a covariate. To account for those differences (detected covariates), analysis of covariance (ANCOVA) was employed to compare the effects of the 3 different graft types on thigh circumference, knee ROMs, quadriceps, hamstrings, hip abductor, and hip extensor. When statistical significance was indicated, pairwise Bonferroni post hoc comparisons (BTB vs HS, HS vs ITB, and ITB vs BTB) were performed to correct inflated P values and to identify statistical significance within the pairs. A priori statistical significance was set as P < .05, and the IBM SPSS statistical software (version 21; SPSS Inc, Chicago, IL) was used for all analyses.

Results

Patients’ characteristics, including demographic information, meniscus tear status, presurgical functional knee outcome scores, and duration from ACLR surgery to the physical measurements, are listed on Table 1. Covariance analysis indicated statistically significant differences in patients’ ages, heights, weights, and BMIs. As age, height, weight, and BMI were all colinear among each other, BMI was selected as a representable variable and entered in the ANCOVA model. The ANCOVA indicated there were no statistically significant differences in thigh circumferences (Table 2) and knee ROM measurements (Table 3). For muscle strength measurements, the ANCOVA detected significant differences between the deficits of quadriceps strength (P = .003) and hamstrings strength (P = .001) among the 3 autograft types (Table 4). The Bonferroni post hoc analyses confirmed significantly greater quadriceps strength deficits (12.2%) in the BTB cohort compared with the HS (P = .002) and ITB (P = .03) groups. Also, hamstrings strength deficits (31.7%) were statistically significant in patients with HS group compared with the BTB (P = .001) and ITB (P = .001) groups. No significant deficits were found in hip abductor and hip-extensor strength among the 3 autograft cohort.

Table 1

Patient Characteristics

Graft typesBTB (n = 20)HS (n = 111)ITB (n = 33)P values
Demographics
 Age, y17.1 (4.8)17.0 (2.2)13.3 (1.3).001*
 Height, cm176.5 (19.0)174.9 (8.1)160.3 (11.5).001*
 Weight, kg91.1 (21.2)73.2 (15.2)57.3 (19.2).001*
 BMI30.3 (11.7)23.9 (4.3)22.1 (5.8).001*
Meniscus tears
 No84817
 Yes126016.68
Duration from ACLR to measurements
 Months6.5 (1.5)6.4 (1.1)6.2 (0.7).55

Abbreviations: ACLR, anterior cruciate ligament reconstruction; BMI, body mass index; BTB, bone–patellar tendon–bone; HS, hamstring; ITB, iliotibial band. Note: Values are represented as mean (SD). Age: participants with ITB are significantly different from BTB and HS (P = .001 in ITB vs BTB comparison and P = .001 in ITB vs HS comparison). Height: participants with ITB are significantly different from BTB and HS (P = .001 in ITB vs BTB comparison and P = .01 in ITB vs HS comparison). Weight: participants with BTB, HG, and IT band are significantly different among each other (P = .001 in BTB vs ITB comparison, P = .001 in HS vs ITB comparison, and P = .001 in BTB vs HS comparison). BMI: participants with BTB are significantly different from HS and ITB (P = .001 in BTB vs HS comparison and P = .001 in BTB vs ITB comparison).

*P < .05.

Table 2

Thigh Circumference Deficits Based on the 3 Graft Types

Graft typeBTB (n = 20)HS (n = 111)ITB (n = 33)P values
Thigh circumference
 Uninvolved limb47.7 (45.8 to 49.7)46.3 (45.4 to 47.1)43.1 (41.7 to 44.6)
 ACLR limb46.2 (44.2 to 48.3)44.8 (43.9 to 45.6)42.6 (41.1 to 44.0)
Deficits, %−3.1 (−4.5 to −1.7)−3.2 (−3.8 to −2.6)−1.3 (−2.3 to −0.2).06

Note: Values are mean and 95% confidence interval.

Table 3

ROM Deficits in Knee Extension and Flexion Based on the 3 Graft Types

Graft typeBTB (n = 20)HS (n = 111)ITB (n = 33)P values
Knee extension ROM, deg
 Uninvolved limb3.99 (2.65 to 5.32)3.74 (3.18 to 4.30)4.95 (3.96 to 5.94)
 ACLR limb2.47 (1.07 to 3.88)2.51 (1.91 to 3.10)3.99 (2.95 to 5.03)
Deficits, %−22.5 (−48.1 to 0.3)−30.0 (−40.8 to −19.2)−19.9 (−38.8 to −1.1).60
Knee-flexion ROM, deg
 Uninvolved limb130.4 (123.2 to 137.5)131.2 (128.2 to 134.1)133.2 (128.1 to 138.4)
 ACLR limb128.7 (124.2 to 133.3)128.8 (127.0 to 130.7)134.4 (131.2 to 137.7)
Deficits, %6.6 (−6.6 to 19.8)−2.1 (−48.6 to 44.5)80.3 (−1.0 to 61.6).22

Abbreviation: ACLR, anterior cruciate ligament reconstruction; ROM, range of motion. Note: Values are mean and 95% confidence interval. ROM was measured passively. Values are hyperextension (greater than 0° or 180°) of knee extension.

Table 4

Strength Deficits in Normalized Quadriceps, Hamstrings, Hip Abductors, and Hip-Extensor Muscular Strength Based on the 3 Graft Types

Graft typeBTB (n = 20)HS (n = 111)ITB (n = 33)P values
Quadriceps strength, N/kg
 Uninvolved limb5.2 (4.6 to 5.8)4.7 (4.4 to 4.9)4.4 (4.0 to 4.8)
 ACLR limb4.6 (3.9 to 5.2)4.7 (4.4 to 4.9)4.3 (3.9 to 4.7)
Deficits, %−12.2 (−18.9 to −5.5)0.5 (−2.1 to 3.2)−1.2 (−6.0 to 3.5).003*
Hamstrings strength, N/kg
 Uninvolved limb2.4 (2.1 to 2.8)2.4 (2.2 to 2.5)2.5 (2.4 to 2.8)
 ACLR limb2.3 (1.9 to 2.6)1.6 (1.5 to 1.8)2.3 (2.1 to 2.6)
Deficits, %−5.4 (−14.8 to 3.9)−31.7 (−35.5 to −28.0)−7.7 (−14.4 to −1.0).001*
Hip abductor strength, N/kg
 Uninvolved limb2.3 (1.9 to 2.6)2.0 (1.9 to 2.1)1.6 (1.4 to 1.8)
 ACLR limb2.2 (1.9 to 2.5)2.0 (1.9 to 2.2)1.6 (1.4 to 1.8)
Deficits, %−2.6 (−11.7 to 6.6)3.4 (−0.5 to 7.3)1.3 (−5.4 to 8.0).47
Hip-extensor strength, N/kg
 Uninvolved limb3.5 (2.9 to 4.0)3.1 (2.9 to 3.4)3.2 (2.8 to 3.6)
 ACLR limb3.5 (2.9 to 4.1)3.2 (3.0 to 3.5)3.3 (2.9 to 3.7)
Deficits, %0.3 (−4.8 to 11.1)0.3 (−0.7 to 0.6)0.3 (−0.3 to 0.9).10

Abbreviations: ACLR, anterior cruciate ligament reconstruction; BTB, bone–patellar tendon–bone; HS, hamstring; ITB, iliotibial band. Note: Values are mean and 95% confidence interval. Quadriceps strength deficits: BTB group was significantly different compared with HS (P = .002) and ITB (P = .03) groups. Hamstrings strength deficits: ACLR limb in HS was significantly different from BTB (P = .001) and ITB (P = .001) groups. Deficits in HS was significantly different compared with BTB (P = .001) and ITB (P = .001) groups.

*P < .05.

Discussion

The most salient finding of this study was that graft type significantly influenced deficits in quadriceps and hamstrings strength. Children and adolescents who underwent ACLR with BTB and HS autografts demonstrated significantly greater quadriceps and hamstring strength deficits than the other respective graft type (ITB), respectively. The strength deficits were directly related to where the graft was harvested: those who had BTB showed 12.2% deficits in quadriceps strength, and patients with HS also demonstrated 31.7% hamstring deficits (Table 4). The current study focused on male ACLR patients younger than 22 of age. A previous study compared strength deficits by HS and ITB grafts in a skeletally immature population (mean age range 12.5–13.6 y) following ACLR surgery.15 The findings of this study were consistent with the previous study and suggest that the HS graft significantly influences hamstring strength deficits (32.2%) regardless of skeletal maturity.15 Both studies indicated significant effects of HS graft on hamstring strength deficits regardless status of skeletal maturity.

Patients with BTB showed 12.2% of strength deficits relative to the uninvolved side, which was significant compared with HS and ITB (Table 4). Several studies reported that quadriceps strength is directly associated with functional tasks, such as dynamic postural stability,42 jump-landing tasks,4345 and gait.46 In addition, quadriceps strength deficits have been shown to be linked to increased fear and a lack of confidence, which may further have an effect on the safe return to preinjury sports participation.47 Also, recently published consensus criteria for a successful outcome following ACLR stated that greater than 90% of quadriceps strength, compared with the uninvolved side, is ideal.7 Therefore, recovery of quadriceps strength is an important priority. However, long-term quadriceps strength deficits after ACLR have been reported at 2–3 years postoperatively in ACLR patients.17 The long-term effect of graft choice on strength deficits is unknown at this point, however, and it remains an important area of continuing investigation. The current results suggest that youth patients who had BTB procedure exhibited an average of 12.2% strength deficits at 6- to 9-month post-ACL follow-up visits.

Another unexpected finding was quadriceps strength differences in the uninvolved limb in the 3 graft cohorts (Table 4). Quadriceps strength was notably greater in BTB group compared with HS and ITB groups (Table 4). Also, the pediatric and adolescent males who underwent BTB procedures were relatively older, taller, and heavier (Table 1). The ITB autograft technique was developed for skeletally immature ACLR patients, and a clinical algorithm of the ACLR graft selections, based on various physical maturation phases, was previously depicted.30 In order to reduce the difference in uninvolved limb among the 3 graft groups, limb symmetry index was employed, and the deficits (in percentage) were calculated. Also, in order to control effects of physical variability (Table 1), the ANCOVA model was used, and BMI was treated as a covariate. Thus, effects of referenced limb and baseline differences on the current results were considered minimal.

The greatest deficits were observed in hamstring strength among patients with a HS autograft, who demonstrated a mean deficit of 31.7% compared with the uninvolved side (Table 4). This value was significantly greater than those seen in the BTB and ITB (Table 4). The hamstring strength deficits were greater than quadriceps strength deficits of patients with BTB. The HS procedure usually requires harvesting 2 distal tendons, which are the gracilis and semitendinosus.48 Using 2 different distal tendons may potentially influence the greater deficits of hamstring strength rather than a tendon from one muscle group. Furthermore, the hamstring strength deficits in the HS cohort contributed a lower hamstring to quadriceps strength ratio compared with BTB and ITB cohorts. In the HS group, hamstring strength was only 34% of quadriceps strength, compared with 52% and 54% in both BTB and ITB groups, respectively. This is concerning because a decreased hamstring to quadriceps strength ratio was found as a risk factor for ACL graft rupture.10 In this study, young adult (no ACL graft rupture group: 21 [4] y; ACL graft rupture group: 22 [5] y) male soccer players who had ACLR surgeries with either BTB or HS autografts were followed after their return to sport (mean follow-up time after ACLR surgery: 229 d, range: 116–513 d).10 During the follow-up period, the decreased hamstring to quadriceps strength ratio was identified as one of the 2 major risk factors of ACL graft rupture.10 The hamstrings to quadriceps strength ratio was 58% in those who did not sustain graft rupture, whereas the value was 55% among those who suffered ACL graft rupture.10 In our study, both BTB and ITB patients were closer to reaching the threshold (BTB group: 52% and ITB group: 54%); however, the HS group showed considerably low hamstring to quadriceps strength ratio (34%).

Based on our findings of the current research, some components of the post-ACLR strength deficits stem from the effect of graft type and donor site morbidity. Patients who underwent a BTB autograft demonstrated the greatest quadriceps deficits compared with other 2 graft cohorts. Similarly, hamstring strength deficits in patients with HS autograft were greater than that in the other 2 graft groups. Interestingly, those who had ITB autograft did not demonstrate significant deficits in hip abductor strength at 6 to 9 months post-ACLR. Instead, patients in ITB demonstrated 1.3% greater hip abductor strength in ACLR side in relation to the uninvolved side at 6 months postoperatively (Table 4). It may be speculated that such findings are the result of different developmental phases, because those who had ITB autograft were significantly younger (Table 1). However, those factors were adjusted in the ANCOVA as covariates. Patients in ITB autograft demonstrated either minimum deficits or actually gain in muscular strength even though a part of the ITB was used as an autograft. Further investigation is necessary to understand the underlying mechanism and explore long-term outcomes. However, the current results indicate that ITB autograft may be an ideal graft option to allow for reconditioning and optimization of lower-extremity recovery after ACLR.

Limitations

A few limitations need to be stated. First, the current study was not a randomized, controlled trial. However, in order to adjust for potential differences in our participants, we employed an ANCOVA model. The ANCOVA model can control potential covariates, such as age and body size differences, which were identified as significantly different parameters in participants at the baseline. Thus, this approach ensured a quality result presented in this study. Second, this project initially aimed to include both male and female populations. However, there were only few cases of ACLR surgeries utilizing BTB and ITB grafts in the female population, which led to focusing on only males. This approach helped maintain a homogeneous population. Sex differences have been identified in patients with ACL injuries and reconstructions3137; therefore, analyzing only the male population in this study makes the results nongeneralizable to female populations. This may be a notable weakness of this study, because physically active teenage females sustained ACL injury at a greater rate compared with their male counterparts.2,49 Third, detailed information of physical therapy was lacking in our study. It is logical to consider that muscle strength improvement may be reflective of duration and the effectiveness of the postoperative physical rehabilitation program. We generally provide a rehabilitative protocol, developed by the MOON group, to our ACLR patients.50 In addition, most of our ACLR patients performed more than 20 physical therapy sessions before their tests. However, the contents of rehabilitation, such as specific exercises, sets × repetitions, and clinical modalities, were not included in the current study. Finally, other limitations include the absence of follow-up information in the same patients at subsequent strength testing periods, such as at 12 and 24 months. The periods may be more applicable to modern standard of care time points for a full return to sport, thereby making the 6- to 9-month metrics somewhat less clinically applicable. If all groups recover to reasonable degrees over the 3- to 6-month period following the current testing, concerns about graft harvest may be allayed, to a degree.

Conclusion

The main findings of this study are that there are no significant differences in thigh circumferences and knee ROM among the 3 graft types. However, in muscle strength measurements, pediatric and adolescent male ACLR patients who had BTB and HS procedures show significant deficits in quadriceps (12.2%) and hamstring (31.7%) strength, respectively. The anatomical sites where the graft was harvested likely influenced strength recovery at the 6- to 9-month post-ACLR measures, with the exception of patients with ITB autografts, who do not exhibit significant strength deficits. The results of the current study may assist surgeon and families, both in the application of graft selection criteria, as well as in the determination of appropriate timing of return to play. Future studies are necessary to overcome the limitations listed earlier and to investigate the optional approach to ACL injury treatment and prevention in the growing population of youth athletes.

Acknowledgments

There is no funding source. The authors declare that they have no conflict of interest. Ethical approval was obtained from institutional review board of the hosting institution.

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    Edwards PK, Ebert JR, Joss B, et al. Patient characteristics and predictors of return to sport at 12 months after anterior cruciate ligament reconstruction: the importance of patient age and postoperative rehabilitation. Orthop J Sports Med. 2018;6(9):2325967118797575. PubMed ID: 30263898 doi:10.1177/2325967118797575

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    Sousa PL, Krych AJ, Cates RA, Levy BA, Stuart MJ, Dahm DL. Return to sport: does excellent 6-month strength and function following ACL reconstruction predict midterm outcomes? Knee Surg Sports Traumatol Arthrosc. 2017;25(5):13561363. doi:10.1007/s00167-015-3697-2

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    Greenberg EM, Greenberg ET, Ganley TJ, Lawrence JT. Strength and functional performance recovery after anterior cruciate ligament reconstruction in preadolescent athletes. Sports Health. 2014;6(4):309312. PubMed ID: 24982702 doi:10.1177/1941738114537594

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    Sugimoto D, Heyworth BE, Collins SE, Fallon RT, Kocher MS, Micheli LJ. Comparison of lower extremity recovery after anterior cruciate ligament reconstruction with transphyseal hamstring versus extraphyseal iliotibial band techniques in skeletally immature athletes. Orthop J Sports Med. 2018;6(4):2325967118768044. PubMed ID: 29780839 doi:10.1177/2325967118768044

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    Sugimoto D, Heyworth BE, Brodeur JJ, Kramer DE, Kocher MS, Micheli LJ. Effect of graft type on balance and hop tests in adolescent males following anterior cruciate ligament reconstruction [published online ahead of print February 21, 2018]. J Sport Rehabil. 2018;127. doi:10.1123/jsr.2017-0244

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    Otzel DM, Chow JW, Tillman MD. Long-term deficits in quadriceps strength and activation following anterior cruciate ligament reconstruction. Phys Ther Sport. 2015;16(1):2228. PubMed ID: 24933688 doi:10.1016/j.ptsp.2014.02.003

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    Thomas AC, Villwock M, Wojtys EM, Palmieri-Smith RM. Lower extremity muscle strength after anterior cruciate ligament injury and reconstruction. J Athl Train. 2013;48(5):610620. PubMed ID: 24067150 doi:10.4085/1062-6050-48.3.23

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    Hsiao SF, Chou PH, Hsu HC, Lue YJ. Changes of muscle mechanics associated with anterior cruciate ligament deficiency and reconstruction. J Strength Cond Res. 2014;28(2):390400. PubMed ID: 23669818 doi:10.1519/JSC.0b013e3182986cc1

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    Tan SHS, Huh LBP, Krishna L. Outcomes of Anterior Cruciate Ligament Reconstruction in females using patellar-tendon-bone versus hamstring autografts: a systematic review and meta-analysis [published online ahead of print September 13, 2018]. J Knee Surg. 2018. doi:10.1055/s-0038-1669916

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    Herbst E, Hoser C, Gfoller P, et al. Impact of surgical timing on the outcome of anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc. 2017;25(2):569577. PubMed ID: 27549214 doi:10.1007/s00167-016-4291-y

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    Halinen J, Lindahl J, Hirvensalo E. Range of motion and quadriceps muscle power after early surgical treatment of acute combined anterior cruciate and grade-III medial collateral ligament injuries. A prospective randomized study. J Bone Joint Surg Am. 2009;91(6):13051312. PubMed ID: 19487506 doi:10.2106/JBJS.G.01571

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    Della Villa S, Boldrini L, Ricci M, et al. Clinical outcomes and return-to-sports participation of 50 soccer players after anterior cruciate ligament reconstruction through a sport-specific rehabilitation protocol. Sports health. 2012;4(1):1724. PubMed ID: 23016064 doi:10.1177/1941738111417564

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    Yu B, Garrett WE. Mechanisms of non-contact ACL injuries. Br J Sports Med. 2007;41(suppl 1):i47i51. doi:10.1136/bjsm.2007.037192

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    Hashemi J, Breighner R, Jang TH, Chandrashekar N, Ekwaro-Osire S, Slauterbeck JR. Increasing pre-activation of the quadriceps muscle protects the anterior cruciate ligament during the landing phase of a jump: an in vitro simulation. Knee. 2010;17(3):235241. PubMed ID: 19864146 doi:10.1016/j.knee.2009.09.010

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    Amis AA, Dawkins GP. Functional anatomy of the anterior cruciate ligament. Fibre bundle actions related to ligament replacements and injuries. J Bone Joint Surg Br 1991;73(2):260267. PubMed ID: 2005151 doi:10.1302/0301-620X.73B2.2005151

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    Kocher MS, Smith JT, Zoric BJ, Lee B, Micheli LJ. Transphyseal anterior cruciate ligament reconstruction in skeletally immature pubescent adolescents. J Bone Joint Surg Am. 2007;89(12):26322639. PubMed ID: 18056495 doi:10.2106/JBJS.F.01560

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    Micheli LJ, Rask B, Gerberg L. Anterior cruciate ligament reconstruction in patients who are prepubescent. Clin Orthop Relat Res. 1999(364):4047.

    • Search Google Scholar
    • Export Citation
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    Kocher MS, Garg S, Micheli LJ. Physeal sparing reconstruction of the anterior cruciate ligament in skeletally immature prepubescent children and adolescents. J Bone Joint Surg Am. 2005;87(11):23712379. PubMed ID: 16264110

    • PubMed
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    • Export Citation
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    Kocher MS, Garg S, Micheli LJ. Physeal sparing reconstruction of the anterior cruciate ligament in skeletally immature prepubescent children and adolescents. Surgical technique. J Bone Joint Surg Am. 2006;88(suppl 1, pt 2):283293. doi:10.2106/00004623-200609001-00012

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    Asaeda M, Deie M, Fujita N, et al. Gender differences in the restoration of knee joint biomechanics during gait after anterior cruciate ligament reconstruction. Knee. 2017;24(2):280288. PubMed ID: 28173988 doi:10.1016/j.knee.2017.01.001

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    Webster KE, Feller JA. Return to level I sports after anterior cruciate ligament reconstruction: evaluation of age, sex, and readiness to return criteria. Orthop J Sports Med. 2018;6(8):2325967118788045. PubMed ID: 30116761 doi:10.1177/2325967118788045

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    Kanamoto T, Tanaka Y, Yonetani Y, et al. Sex differences in the residual patellar tendon after harvesting its central third for anterior cruciate ligament reconstruction. J Ultrasound Med. 2018;37(3):755761. PubMed ID: 28945278 doi:10.1002/jum.14419

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    Kim DK, Park WH. Sex differences in knee strength deficit 1 year after anterior cruciate ligament reconstruction. J Phys Ther Sci. 2015;27(12):38473849. PubMed ID: 26834366 doi:10.1589/jpts.27.3847

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    Kluczynski MA, Marzo JM, Rauh MA, Bernas GA, Bisson LJ. Sex-specific predictors of intra-articular injuries observed during anterior cruciate ligament reconstruction. Orthop J Sports Med. 2015;3(2):2325967115571300. PubMed ID: 26535384 doi:10.1177/2325967115571300

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    Teitsma XM, van der Hoeven H, Tamminga R, de Bie RA. Impact of patient sex on clinical outcomes: data from an anterior cruciate ligament reconstruction registry, 2008–2013. Orthop J Sports Med. 2014;2(9):2325967114550638. PubMed ID: 26535365 doi:10.1177/2325967114550638

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If the inline PDF is not rendering correctly, you can download the PDF file here.

Sugimoto, Heyworth, Yates, Kramer, Kocher, and Micheli are with The Micheli Center for Sports Injury Prevention, Waltham, MA; and the Division of Sports Medicine, Department of Orthopedics, Boston Children’s Hospital, Boston, MA. Sugimoto, Heyworth, Kramer, Kocher, and Micheli are also with Harvard Medical School, Boston, MA.

Sugimoto (dai.sugimoto@childrens.harvard.edu) is corresponding author.
  • View in gallery

    —Illustration of physeal-sparing autograft technique.

  • View in gallery

    —Images of knee extension (A) and flexion (B) range of motion measurements.

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    Sousa PL, Krych AJ, Cates RA, Levy BA, Stuart MJ, Dahm DL. Return to sport: does excellent 6-month strength and function following ACL reconstruction predict midterm outcomes? Knee Surg Sports Traumatol Arthrosc. 2017;25(5):13561363. doi:10.1007/s00167-015-3697-2

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    Greenberg EM, Greenberg ET, Ganley TJ, Lawrence JT. Strength and functional performance recovery after anterior cruciate ligament reconstruction in preadolescent athletes. Sports Health. 2014;6(4):309312. PubMed ID: 24982702 doi:10.1177/1941738114537594

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15.

    Sugimoto D, Heyworth BE, Collins SE, Fallon RT, Kocher MS, Micheli LJ. Comparison of lower extremity recovery after anterior cruciate ligament reconstruction with transphyseal hamstring versus extraphyseal iliotibial band techniques in skeletally immature athletes. Orthop J Sports Med. 2018;6(4):2325967118768044. PubMed ID: 29780839 doi:10.1177/2325967118768044

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    • Search Google Scholar
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  • 16.

    Sugimoto D, Heyworth BE, Brodeur JJ, Kramer DE, Kocher MS, Micheli LJ. Effect of graft type on balance and hop tests in adolescent males following anterior cruciate ligament reconstruction [published online ahead of print February 21, 2018]. J Sport Rehabil. 2018;127. doi:10.1123/jsr.2017-0244

    • Search Google Scholar
    • Export Citation
  • 17.

    Otzel DM, Chow JW, Tillman MD. Long-term deficits in quadriceps strength and activation following anterior cruciate ligament reconstruction. Phys Ther Sport. 2015;16(1):2228. PubMed ID: 24933688 doi:10.1016/j.ptsp.2014.02.003

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18.

    Thomas AC, Villwock M, Wojtys EM, Palmieri-Smith RM. Lower extremity muscle strength after anterior cruciate ligament injury and reconstruction. J Athl Train. 2013;48(5):610620. PubMed ID: 24067150 doi:10.4085/1062-6050-48.3.23

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19.

    Hsiao SF, Chou PH, Hsu HC, Lue YJ. Changes of muscle mechanics associated with anterior cruciate ligament deficiency and reconstruction. J Strength Cond Res. 2014;28(2):390400. PubMed ID: 23669818 doi:10.1519/JSC.0b013e3182986cc1

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20.

    Tan SHS, Huh LBP, Krishna L. Outcomes of Anterior Cruciate Ligament Reconstruction in females using patellar-tendon-bone versus hamstring autografts: a systematic review and meta-analysis [published online ahead of print September 13, 2018]. J Knee Surg. 2018. doi:10.1055/s-0038-1669916

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 21.

    Herbst E, Hoser C, Gfoller P, et al. Impact of surgical timing on the outcome of anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc. 2017;25(2):569577. PubMed ID: 27549214 doi:10.1007/s00167-016-4291-y

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 22.

    Halinen J, Lindahl J, Hirvensalo E. Range of motion and quadriceps muscle power after early surgical treatment of acute combined anterior cruciate and grade-III medial collateral ligament injuries. A prospective randomized study. J Bone Joint Surg Am. 2009;91(6):13051312. PubMed ID: 19487506 doi:10.2106/JBJS.G.01571

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 23.

    Della Villa S, Boldrini L, Ricci M, et al. Clinical outcomes and return-to-sports participation of 50 soccer players after anterior cruciate ligament reconstruction through a sport-specific rehabilitation protocol. Sports health. 2012;4(1):1724. PubMed ID: 23016064 doi:10.1177/1941738111417564

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 24.

    Yu B, Garrett WE. Mechanisms of non-contact ACL injuries. Br J Sports Med. 2007;41(suppl 1):i47i51. doi:10.1136/bjsm.2007.037192

  • 25.

    Hashemi J, Breighner R, Jang TH, Chandrashekar N, Ekwaro-Osire S, Slauterbeck JR. Increasing pre-activation of the quadriceps muscle protects the anterior cruciate ligament during the landing phase of a jump: an in vitro simulation. Knee. 2010;17(3):235241. PubMed ID: 19864146 doi:10.1016/j.knee.2009.09.010

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 26.

    Amis AA, Dawkins GP. Functional anatomy of the anterior cruciate ligament. Fibre bundle actions related to ligament replacements and injuries. J Bone Joint Surg Br 1991;73(2):260267. PubMed ID: 2005151 doi:10.1302/0301-620X.73B2.2005151

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 27.

    Kocher MS, Smith JT, Zoric BJ, Lee B, Micheli LJ. Transphyseal anterior cruciate ligament reconstruction in skeletally immature pubescent adolescents. J Bone Joint Surg Am. 2007;89(12):26322639. PubMed ID: 18056495 doi:10.2106/JBJS.F.01560

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 28.

    Micheli LJ, Rask B, Gerberg L. Anterior cruciate ligament reconstruction in patients who are prepubescent. Clin Orthop Relat Res. 1999(364):4047.

    • Search Google Scholar
    • Export Citation
  • 29.

    Kocher MS, Garg S, Micheli LJ. Physeal sparing reconstruction of the anterior cruciate ligament in skeletally immature prepubescent children and adolescents. J Bone Joint Surg Am. 2005;87(11):23712379. PubMed ID: 16264110

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 30.

    Kocher MS, Garg S, Micheli LJ. Physeal sparing reconstruction of the anterior cruciate ligament in skeletally immature prepubescent children and adolescents. Surgical technique. J Bone Joint Surg Am. 2006;88(suppl 1, pt 2):283293. doi:10.2106/00004623-200609001-00012

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 31.

    Asaeda M, Deie M, Fujita N, et al. Gender differences in the restoration of knee joint biomechanics during gait after anterior cruciate ligament reconstruction. Knee. 2017;24(2):280288. PubMed ID: 28173988 doi:10.1016/j.knee.2017.01.001

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 32.

    Webster KE, Feller JA. Return to level I sports after anterior cruciate ligament reconstruction: evaluation of age, sex, and readiness to return criteria. Orthop J Sports Med. 2018;6(8):2325967118788045. PubMed ID: 30116761 doi:10.1177/2325967118788045

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 33.

    Kanamoto T, Tanaka Y, Yonetani Y, et al. Sex differences in the residual patellar tendon after harvesting its central third for anterior cruciate ligament reconstruction. J Ultrasound Med. 2018;37(3):755761. PubMed ID: 28945278 doi:10.1002/jum.14419

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 34.

    Kim DK, Park WH. Sex differences in knee strength deficit 1 year after anterior cruciate ligament reconstruction. J Phys Ther Sci. 2015;27(12):38473849. PubMed ID: 26834366 doi:10.1589/jpts.27.3847

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 35.

    Kluczynski MA, Marzo JM, Rauh MA, Bernas GA, Bisson LJ. Sex-specific predictors of intra-articular injuries observed during anterior cruciate ligament reconstruction. Orthop J Sports Med. 2015;3(2):2325967115571300. PubMed ID: 26535384 doi:10.1177/2325967115571300

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 36.

    Teitsma XM, van der Hoeven H, Tamminga R, de Bie RA. Impact of patient sex on clinical outcomes: data from an anterior cruciate ligament reconstruction registry, 2008–2013. Orthop J Sports Med. 2014;2(9):2325967114550638. PubMed ID: 26535365 doi:10.1177/2325967114550638

    • PubMed
    • Search Google Scholar
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