Clinical Outcomes After Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction: Comparison of Extreme Knee Hyperextension and Normal to Mild Knee Hyperextension

Quadriceps Tendon With Bone Autograft Has Better Stability and Magnetic Resonance Imaging Maturation Than Hamstring Tendon Autograft After Anterior Cruciate Ligament Reconstruction in Patients With Knee Hyperextension

PURPOSE

To compare the clinical outcomes of anterior cruciate ligament (ACL) reconstruction between methods using quadriceps tendon with bone (QTB) and hamstring tendon (HT) in patients with hyperextension of the knee.

METHODS

The medical records of patients with knee hyperextension greater than 8° who underwent arthroscopic ACL reconstruction between October 2010 and October 2020 with follow-up for at least 2 years (median, 3 years; interquartile range [IQR], 2.0-4.6 years) were retrospectively reviewed. Side-to-side difference in anterior translation, pivot-shift test grade, Lysholm score, and graft intensity using the Howell grade on magnetic resonance imaging at final follow-up were compared between the QTB and HT groups.

RESULTS

The HT and QTB groups consisted of 42 patients and 21 patients, respectively. The overall mean age was 21.5 years (range, 14-48 years), and the median Tegner Activity Scale score was 6 (range, 3-9). Postoperatively, the median side-to-side difference in anterior translation was 1.75 mm (IQR, 1-3 mm) in the HT group and 1.0 mm (IQR, 0-1.75 mm) in the QTB group (P = .01). Pivot-shift testing showed grade 0 in 74.7%, grade 1 in 18.7%, and grade 2 in 6.6% of patients in the HT group and grade 0 in 85.7% and grade 1 in 14.3% of those in the QTB group (P = .03). The median postoperative Lysholm score was 99 in both groups. Graft signal intensity showed a significant between-group difference: grade I in 52%, grade II in 36%, and grade III in 12% of patients in the HT group versus grade I in 85.7%, grade II in 9.5%, and grade III in 4.8% of those in the QTB group (P = .03).

CONCLUSIONS

In patients who underwent ACL reconstruction for hyperextension of the knee, QTB yielded better clinical outcomes than HT with respect to anterior stability, rotational stability, and graft signal intensity on median 2-year follow-up magnetic resonance imaging.

LEVEL OF EVIDENCE

Level III, retrospective case-control study.

Predictors of Graft Failure in Young Active Patients Undergoing Hamstring Autograft Anterior Cruciate Ligament Reconstruction With or Without a Lateral Extra-articular Tenodesis: The Stability Experience

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction (ACLR) has higher failure rates in young active patients returning to sports as compared with older, less active individuals. Augmentation of ACLR with an anterolateral procedure has been shown to reduce failure rates; however, indications for this procedure have yet to be clearly defined.

PURPOSE/HYPOTHESIS

The purpose of this study was to identify predictors of ACL graft failure in high-risk patients and determine key indications for when hamstring ACLR should be augmented by a lateral extra-articular tenodesis (LET). We hypothesized that different preoperative characteristics and surgical variables may be associated with graft failure characterized by asymmetric pivot shift and graft rupture.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Data were obtained from the Stability 1 Study, a multicenter randomized controlled trial of young active patients undergoing autologous hamstring ACLR with or without a LET. We performed 2 multivariable logistic regression analyses, with asymmetric pivot shift and graft rupture as the dependent variables. The following were included as predictors: LET, age, sex, graft diameter, tear chronicity, preoperative high-grade knee laxity, preoperative hyperextension on the contralateral side, medial meniscal repair/excision, lateral meniscal repair/excision, posterior tibial slope angle, and return-to-sports exposure time and level.

RESULTS

Of the 618 patients in the Stability 1 Study, 568 with a mean age of 18.8 years (292 female; 51.4%) were included in this analysis. Asymmetric pivot shift occurred in 152 (26.8%) and graft rupture in 43 (7.6%). The addition of a LET (odds ratio [OR], 0.56; 95% CI, 0.37-0.83) and increased graft diameter (OR, 0.62; 95% CI, 0.44-0.87) were significantly associated with lower odds of asymmetric pivot shift. The addition of a LET (OR, 0.40; 95% CI, 0.18-0.91) and older age (OR, 0.83; 95% CI, 0.72-0.96) significantly reduced the odds of graft rupture, while greater tibial slope (OR, 1.15; 95% CI, 1.01-1.32), preoperative high-grade knee laxity (OR, 3.27; 95% CI, 1.45-7.41), and greater exposure time to sport (ie, earlier return to sport) (OR, 1.18; 95% CI, 1.08-1.29) were significantly associated with greater odds of rupture.

CONCLUSION

The addition of a LET and larger graft diameter were significantly associated with reduced odds of asymmetric pivot shift. Adding a LET was protective of graft rupture, while younger age, greater posterior tibial slope, high-grade knee laxity, and earlier return to sport were associated with increased odds of graft rupture. Orthopaedic surgeons should consider supplementing hamstring autograft ACLR with a LET in young active patients with morphological characteristics that make them at high risk of reinjury.

Knee Hyperextension Greater Than 5° Is a Risk Factor for Failure in ACL Reconstruction Using Hamstring Graft

Background:

The degree of knee hyperextension in isolation has not been studied in detail as a risk factor that could lead to increased looseness or graft failure after anterior cruciate ligament (ACL) reconstruction.

Purpose:

To analyze whether more than 5° of passive knee hyperextension is associated with worse functional outcomes and greater risk of graft failure after primary ACL reconstruction with hamstring tendon autograft.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A cohort of patients who had primary ACL reconstruction with hamstring tendon autografts was divided into 2 groups based on passive contralateral knee hyperextension greater than 5° (hyperextension group) and less than 5° (control group) of hyperextension. Groups were matched by age, sex, and associated meniscal tears. The following data were collected and compared between the groups: patient data (age and sex), time from injury to surgery, passive knee hyperextension, KT-1000 arthrometer laxity, pivot shift, associated meniscal injury and treatment (meniscectomy or repair), contralateral knee ligament injury, intra-articular graft size, follow-up time, occurrence of graft failure, and postoperative Lysholm knee scale and International Knee Documentation Committee subjective form scores.

Results:

Data from 358 patients initially included in the study were analyzed; 22 were excluded because the time from injury to surgery was greater than 24 months, and 22 were lost to follow-up. From the cohort of 314 patients, 102 had more than 5° of knee hyperextension. A control group of the same size (n = 102) was selected by matching among the other 212 patients. Significant differences in the incidence of graft failure (14.7% vs 2.9%; P = .005) and Lysholm knee scale score (86.4 ± 9.8 vs 89.6 ± 6.1; P = .018) were found between the 2 groups.

Conclusion:

Patients with more than 5° of contralateral knee hyperextension submitted to single-bundle ACL reconstruction with hamstring tendons have a higher failure rate than patients with less than 5° of knee hyperextension.

Risk factors for postoperative graft laxity without re-injury after double-bundle anterior cruciate ligament reconstruction in recreational athletes

BACKGROUND

Although high activity is a risk factor for graft failure after anterior cruciate ligament (ACL) reconstruction, the risk factors for postoperative laxity after ACL reconstruction in recreational athletes are unknown.

METHODS

We enrolled 91 patients (40 males, 51 females; mean age 29.2 years; mean follow-up 4.3 years) who scored ≤ 6 on the Tegner activity scale, underwent double-bundle ACL reconstruction between 2010 and 2018, and did not experience re-injury. In the stable group (75 patients, <3.0 mm side-to-side difference (SSD) in anterior translation, grade 0 or 1 pivot shift 1 year after surgery) and unstable group (16 patients, ≥3.0 mm SSD, ≥grade 2 pivot shift), multivariate logistic regression analyses adjusted for factors showing P ≤ 0.3 on univariate analysis assessed risk factors for graft laxity. Lysholm score and graft intensity on MRI (Howell grade) were compared at final follow-up.

RESULTS

Mean SSD in anterior translation was 0.7 mm (stable group) and 3.3 mm (unstable group). Pivot shift grades were 0 (88%) and 1 (12%) in the stable group, and 0 (12.5%), 1 (50%), and 2 (37.5%) in the unstable group. Multivariate regression analyses showed that younger age and knee hyperextension were significant risk factors for graft laxity (P = 0.018 and 0.0016; cutoffs 18 years old and 8°, respectively). Lysholm scores in both groups were comparable, but graft intensity on MRI demonstrated significantly worse Howell grade in the unstable group (P = 0.002).

CONCLUSION

Younger age and knee hyperextension were risk factors for postoperative graft laxity without re-injury in recreational athletes.

Anatomic femoral tunnel placement is difficult by the transtibial technique: comparison of three different femoral tunnel drilling techniques in double-bundle anterior cruciate ligament reconstructions

PURPOSE

To compare the position and direction of femoral and tibial tunnels for both the anteromedial bundle (AMB) and posterolateral bundle (PLB) among three different femoral tunnel drilling techniques, transtibial (TT), transportal (TP), and outside-in (OI) techniques, in anatomic double-bundle ACL reconstruction to clarify advantages and disadvantages of each technique.

METHODS

One-hundred and thirty-nine patients underwent primary ACL reconstruction with an autologous semitendinosus tendon in our institution between 2014 and 2016. Thirteen patients were excluded according to the exclusion criteria. Of the 126 patients, 98 patients agreed to be included in this study. Patients were then randomized into three groups according to the femoral tunnel drilling technique; the TT, TP, and OI groups. Femoral and tibial tunnel angles and positions were measured using three-dimensional computed tomography.

RESULTS

Of patients who agreed to be included in this study, eight patients (seven in TT and one in OI) were excluded since the femoral tunnel could not be created at the intended position. Eighty-six patients (29 in TT, 29 in TP, and 28 in OI) were included for the analyses. Tunnel angles, as well as tunnel lengths, had significant differences among different techniques depending on each technique's characteristics. In terms of tunnel position, femoral tunnel positions of both the AMB and PLB in the TT group were significantly higher than those in the TP group (AMB: p = 0.003, PLB: p = 0.001), and the PLB tunnel position in the TP group had significantly smaller vaciance than that in the TT group (p = 0.004) and OI group (0.002).

CONCLUSIONS

The femoral tunnel positions created by the TT technique were significantly higher, with larger variance, than the TP technique in double-bundle ACL reconstruction, although the positions seemed to be within anatomical footprint. In addition, there were several cases in which femoral tunnels could not be created at the intended position by the TT technique.

LEVEL OF EVIDENCE

I.

Contribution of Additional Anterolateral Structure Augmentation to Controlling Pivot Shift in Anterior Cruciate Ligament Reconstruction

BACKGROUND

Several types of anterolateral structure (ALS) augmentation procedures in anterior cruciate ligament (ACL) reconstruction have been reported. However, information is limited regarding the effect of additional ALS augmentation on rotatory stability in a clinical setting.

PURPOSE/HYPOTHESIS

This study aimed to investigate the contribution of additional ALS augmentation in ACL reconstruction in cases with a high risk of residual pivot shift. The 2 hypotheses were as follows. First, additional ALS augmentation would improve rotatory stability as compared with solely reconstructing the ACL. Second, graft tension changes would be different between the ACL and ALS during knee range of motion and against anterior or rotatory loads.

STUDY DESIGN

Controlled laboratory study.

METHODS

Fifteen patients who met at least 1 of the following criteria were included: (1) revision ACL reconstruction, (2) preoperative high-grade pivot shift, or (3) hyperextended knee. The pivot-shift test was performed preoperatively and during surgery after ACL reconstruction and after additional ALS augmentation with acceleration measurements from a triaxial accelerometer. The tension changes of the ACL and ALS grafts were also measured during knee range of motion and against manual maximum anterior tibial translation, internal rotation, and external rotation.

RESULTS

After ACL reconstruction, the pivot-shift acceleration was still greater than that of the uninjured knee. However, additional ALS augmentation further reduced acceleration when compared with ACL reconstruction alone in both primary and revision cases (P < .05 vs preoperative, P < .05 vs ACL). During knee flexion-extension, the tension of the ACL increased as the knee was extended, whereas that of the ALS did not change. Graft tension of the ACL and ALS became higher with internal rotation and lower with external rotation as compared with the neutral position. Tension of the ACL was significantly increased against anterior tibial translational loads, whereas that of the ALS was not.

CONCLUSION

Additional ALS augmentation further improved the rotatory stability during ACL reconstruction in patients with a high risk of residual pivot shift at the time of surgery. Significant differences in graft tension changes were also observed between the ACL and ALS against different loads. Additional ALS augmentation may be considered to eliminate the pivot shift in patients with a high risk of residual pivot shift.

Risk factors for residual pivot shift after anterior cruciate ligament reconstruction: data from the MAKS group

PURPOSE

To investigate the risk factors for residual pivot shift test after anterior cruciate ligament (ACL) reconstruction based on a multicenter prospective cohort study.

METHODS

This study included patients who were registered in the Multicenter Arthroscopic Knee Surgery Study, a prospective longitudinal multicenter cohort study, and who underwent primary ACL reconstruction using autologous hamstring tendon graft between 2013 and 2016. The exclusion criteria included prior injuries or surgeries in the contralateral knee, prior ligamentous injuries in the involved knee, grade 2 or 3 concomitant ligament injuries, and inflammatory or other forms of osteoarthritis. Data from the preoperative period and at 1-year follow-up were used for further analysis, and patients with incomplete data, re-injury and loss to follow-up were also excluded. Logistic regression analysis was conducted with age, gender, Lachman test, pivot shift test, KT measurement, hyperextension, single-bundle vs. double-bundle, meniscus injury sites, and meniscus treatments as the independent variables, and postoperative pivot shift test was used as the dependent variable.

RESULTS

Three hundred and sixty-eight patients were included in the study. Hyperextension knee (P = 0.025) and a preoperative pivot shift test under anesthesia (P = 0.040) were identified as risk factors for a postoperative pivot shift via logistic regression analysis. There were no statistically significant differences in the other variables.

CONCLUSIONS

The results from a multicenter cohort study indicated that knee hyperextension and greater preoperative pivot shift under anesthesia were risk factors for residual pivot shift at 1 year after ACL reconstruction. In cases with a preoperative high-grade pivot shift and knee hyperextension, additional anterolateral structure augmentation might be considered in order to eliminate pivot shift and eventually obtain better outcomes after ACL reconstruction.

LEVEL OF EVIDENCE

II.

Physiologic Preoperative Knee Hyperextension Is a Predictor of Failure in an Anterior Cruciate Ligament Revision Cohort: A Report From the MARS Group

BACKGROUND

The occurrence of physiologic knee hyperextension (HE) in the revision anterior cruciate ligament reconstruction (ACLR) population and its effect on outcomes have yet to be reported. Hypothesis/Purpose: The prevalence of knee HE in revision ACLR and its effect on 2-year outcome were studied with the hypothesis that preoperative physiologic knee HE ≥5° is a risk factor for anterior cruciate ligament (ACL) graft rupture.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Patients undergoing revision ACLR were identified and prospectively enrolled between 2006 and 2011. Study inclusion criteria were patients undergoing single-bundle graft reconstructions. Patients were followed up at 2 years and asked to complete an identical set of outcome instruments (International Knee Documentation Committee, Knee injury and Osteoarthritis Outcome Score, WOMAC, and Marx Activity Rating Scale) as well as provide information regarding revision ACL graft failure. A regression model with graft failure as the dependent variable included age, sex, graft type at the time of the revision ACL surgery, and physiologic preoperative passive HE ≥5° (yes/no) to assess these as potential risk factors for clinical outcomes 2 years after revision ACLR.

RESULTS

Analyses included 1145 patients, for whom 2-year follow-up was attained for 91%. The median age was 26 years, with age being a continuous variable. Those below the median were grouped as "younger" and those above as "older" (age: interquartile range = 20, 35 years), and 42% of patients were female. There were 50% autografts, 48% allografts, and 2% that had a combination of autograft plus allograft. Passive knee HE ≥5° was present in 374 (33%) patients in the revision cohort, with 52% being female. Graft rupture at 2-year follow-up occurred in 34 cases in the entire cohort, of which 12 were in the HE ≥5° group (3.2% failure rate) and 22 in the non-HE group (2.9% failure rate). The median age of patients who failed was 19 years, as opposed to 26 years for those with intact grafts. Three variables in the regression model were significant predictors of graft failure: younger age (odds ratio [OR] = 3.6; 95% CI, 1.6-7.9; P = .002), use of allograft (OR = 3.3; 95% CI, 1.5-7.4; P = .003), and HE ≥5° (OR = 2.12; 95% CI, 1.1-4.7; P = .03).

CONCLUSION

This study revealed that preoperative physiologic passive knee HE ≥5° is present in one-third of patients who undergo revision ACLR. HE ≥5° was an independent significant predictor of graft failure after revision ACLR with a >2-fold OR of subsequent graft rupture in revision ACL surgery. Registration: NCT00625885 ( ClinicalTrials.gov identifier).

Y-reconstruction could be better for ACL reconstruction in knee hyperextension versus double-bundle double-tunnel technique: a retrospective comparative study of 56 patients

PURPOSE

To compare the clinical outcomes of double-bundle (DB) single-tibial tunnel technique and double-tunnel technique for ACL reconstruction in patients with knee hyperextension.

METHODS

Defined as having constitutional hyperextension of greater than 10°, 56 patients with knee hyperextension who underwent ACL reconstruction were included in this study. To exclude concomitant lesions, preoperative magnetic resonance imaging (MRI) was performed in all knees. 24 patients (Group A) were treated with the anatomic DB/single-tibial tunnel ACL reconstruction and 32 patients (Group B) were treated with DB/double-tibial tunnel ACL reconstruction, all the included patients had knee hyperextension. Clinical results were evaluated by the extension angle, ROM, IKDC 2000 subjective score, rotational stability, pivot-shift test and anterior-posterior translation test before the operation and at the end of follow-up. MRI scan of the knee positioned in full extension was performed after 6 months post-operation. Location of tibial tunnels and graft signal intensity were assessed according to the MRI.

RESULTS

Postoperative extension deficit was detected in Group B, ROM of the injured knee in Group A was from extension angle 8.91 ± 3.16° to flexion angle 115.58 ± 10.53°. ROM of the injured knee in Group B was from extension angle - 2.13 ± 5.88° to flexion angle 119.25 ± 12.63°. Flexion angles of two groups did not show any significant difference (p = 0.24), while extension angles were quite different (p < 0.0001). Group A was slightly higher than Group B in IKDC subjective scores, but without significant difference (Group A 45.1 ± 6.5, Group B 42.4 ± 4.8, p = 0.09). There was no significant difference between two groups in pivot-shift test. Post-operational MRI showed more anterior located tibial tunnel and higher graft signal intensity in Group B when compared with Group A. One patient in the Group B had ligament retear, and required revision surgery.

CONCLUSION

DB/single-tibial tunnel technique restored the knee stability and overcame the shortcomings (such as knee extension deficit and graft impingement) of DB/double tibial tunnel, which might be more suitable for ACL reconstruction in knees with hyperextension.

LEVEL OF EVIDENCE

Level II to III.

Knee hyperextension does not adversely affect dynamic in vivo kinematics after anterior cruciate ligament reconstruction

PURPOSE

To evaluate the effect of knee hyperextension on dynamic in vivo kinematics after anterior cruciate ligament reconstruction (ACL-R).

METHODS

Forty-two patients underwent unilateral ACL-R. Twenty-four months after surgery, subjects performed level walking and downhill running on a treadmill while dynamic stereo radiographs were acquired at 100 (walking) and 150 Hz (running). Tibiofemoral motion was determined using a validated model-based tracking process, and tibiofemoral translations/rotations were calculated. The range of tibiofemoral motions from 0 to 10% of the gait cycle (heel strike to early stance phase) and side-to-side difference (SSD) were calculated. Maximum knee extension angle of ACL-reconstructed knees during walking was defined as active knee extension angle in each subject. Correlations between maximum knee extension angle and tibiofemoral kinematics data were evaluated using Spearman's rho (P < 0.05).

RESULTS

No significant correlation was observed between maximum knee extension angle and the range of anterior tibial translation during functional activities in the ACL-R knees. Maximum knee extension angle was weakly correlated with internal tibial rotation range in ACL-R knee during running (ρ = 0.376, P = 0.014); however, maximum extension angle was not correlated with SSD of internal tibial rotation. SSD of internal tibial rotation was -0.4° ± 1.9° (walking), -1.6° ± 3.1° (running), indicating ACL-R restored rotatory knee range of motion during functional movements.

CONCLUSION

Knee hyperextension was not significantly correlated with greater SSD of anterior translation and internal rotation. The clinical relevance is that knee hyperextension does not adversely affect kinematic outcomes after ACL-R and that physiologic knee hyperextension can be restored after ACL-R when knee hyperextension is present.

LEVEL OF EVIDENCE

III.

The Impact of Osseous Malalignment and Realignment Procedures in Knee Ligament Surgery: A Systematic Review of the Clinical Evidence

Background:

Failure rates of knee ligament surgery may be high, and the impact of osseous alignment on surgical outcome remains controversial. Basic science studies have demonstrated that osseous malalignment can negatively affect ligament strain and that realignment procedures may improve knee joint stability.

Hypothesis/Purpose:

The purpose of this review was to summarize the clinical evidence concerning the impact of osseous malalignment and realignment procedures in knee ligament surgery. The hypotheses were that lower extremity malalignment would be an important contributor to knee ligament surgery failure and that realignment surgery would contribute to increased knee stability and improved outcome in select cases.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

According to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a systematic electronic search of the PubMed database was performed in November 2015 to identify clinical studies investigating (A) the influence of osseous alignment on postoperative stability and/or failure rates after knee ligament surgery and (B) the impact of osseous realignment procedures in unstable knees with or without additional knee ligament surgery on postoperative knee function and stability. Methodological quality of the studies was assessed using the Oxford Centre for Evidence-Based Medicine Levels of Evidence and the Coleman Methodological Score (CMS).

Results:

Of the 1466 potentially relevant articles, 28 studies fulfilled the inclusion and exclusion criteria. Average study quality was poor (CMS, 40). For part A, studies showed increased rerupture rate after anterior cruciate ligament (ACL) replacement in patients with increased tibial slope. Concerning the posterior cruciate ligament (PCL)/posterolateral corner (PLC)/lateral collateral ligament (LCL), varus malalignment was considered a significant risk factor for failure. For part B, studies showed decreased anterior tibial translation after slope-decreasing high tibial osteotomy in ACL-deficient knees. Correcting varus malalignment in PCL/PLC/LCL instability also showed increased stability and better outcomes.

Conclusion:

In cases of complex knee instability, the 3-dimensional osseous alignment of the knee should be considered (eg, mechanical weightbearing line and tibial slope). In cases of failed ACL reconstruction, the tibial slope should be considered, and slope-reducing osteotomies are often helpful in the patient revised multiple times. In cases of chronic PCL and/or PLC instability, osseous correction of the varus alignment may reduce the failure rate and is often the first step in treatment. Changes in the mechanical axis should be considered in all cases of instability accompanied by early unicompartmental osteoarthritis.

The Degree of Knee Extension Does Not Affect Postoperative Stability or Subsequent Graft Tear Rate After Anterior Cruciate Ligament Reconstruction With Patellar Tendon Autograft

BACKGROUND

There is concern that high degrees of hyperextension may lead to an increase in graft laxity or graft failure after anterior cruciate ligament (ACL) reconstruction.

HYPOTHESIS

Patients with a high degree of hyperextension will have a higher rate of graft tear/failure and lower subjective scores after surgery compared with patients with less knee extension.

STUDY DESIGN

Cohort study, Level of evidence, 2.

METHODS

Of 2329 patients who underwent ACL reconstruction with patellar tendon autograft between 1998 and 2008, there were 625 patients who met the inclusion criteria of having primary ACL surgery, no bilateral ACL injuries, no existing osteoarthritis, and having either ≥6° of knee hyperextension before and after surgery (group A: n = 318; mean hyperextension, 8° ± 2° [range, 6°-15°]) or ≤3° of knee hyperextension before and after surgery (group B: n = 307; mean hyperextension, 0° ± 3° [range, 3° hyperextension to -4° short of 0° neutral]). KT-1000 arthrometer manual maximum difference between knees, range of motion measurements, and subjective follow-up with International Knee Documentation Committee (IKDC) and Cincinnati Knee Ratings Scale (CKRS) surveys were used to evaluate results. Subsequent graft tear related to specific injury within 5 years of surgery was recorded. Graft failure was defined as a KT-1000 manual maximum difference of >5 mm.

RESULTS

Follow-up was obtained from 278 (87%) in group A and 275 (90%) in group B at a mean of 4.1 ± 1.1 years after surgery. The KT-1000 arthrometer manual maximum difference between knees was 2.0 ± 1.4 in group A and 2.1 ± 1.6 in group B (P = .701). Subsequent ACL graft tear/failure occurred in 22 patients (6.9%) in group A and 30 patients (9.8%) in group B (P = .246). Further subanalysis showed that the graft tear/failure rate was 6 of 81 (7.4%) for patients with ≥10° of hyperextension versus 16 of 237 (6.8%) for patients with 6° to 9° of hyperextension. There was no difference in IKDC or CKRS scores between groups after surgery (P = .933 and .155, respectively).

CONCLUSION

Obtaining full hyperextension that is anatomically normal for most patients does not affect objective stability, ACL graft tear/failure rates, or subjective scores after ACL reconstruction with patellar tendon autograft.