Two-year postoperative MRI appearances of anterior cruciate ligament hamstrings autografts are not correlated with functional outcomes, anterior laxity, or patient age

Aims MRI has been suggested as an objective method of assessing anterior crucate ligament (ACL) graft “ligamentization” after reconstruction. It has been proposed that the MRI appearances could be used as an indicator of graft maturity and used as part of a return-to-sport assessment. The aim of this study was to evaluate the correlation between MRI graft signal and postoperative functional scores, anterior knee laxity, and patient age at operation. Methods A consecutive cohort of 149 patients who had undergone semitendinosus autograft ACL reconstruction, using femoral and tibial adjustable loop fixations, were evaluated retrospectively postoperatively at two years. All underwent MRI analysis of the ACL graft, performed using signal-to-noise quotient (SNQ) and the Howell score. Functional outcome scores (Lysholm, Tegner, International Knee Documentation Committee (IKDC) subjective, and IKDC objective) were obtained and all patients underwent instrumented side-to-side anterior laxity differential laxity testing. Results Two-year postoperative mean outcome scores were: Tegner 6.5 (2 to 10); Lysholm 89.8 (SD 10.4; 52 to 100); and IKDC subjective 86.8 (SD 11.8; 51 to 100). The objective IKDC score was 86% A (128 patients), 13% B (19 patients), and 1% C (two patients). Mean side-to-side anterior laxity difference (134 N force) was 0.6 mm (SD 1.8; -4.1 to 5.6). Mean graft SNQ was 2.0 (SD 3.5; -14 to 17). Graft Howell scores were I (61%, 91 patients), II (25%, 37 patients), III (13%, 19 patients), and IV (1%, two patients). There was no correlation between either Howell score or SNQ with instrumented anterior or Lysholm, Tegner, and IKDC scores, nor was any correlation found between patient age and ACL graft SNQ or Howell score. Conclusion The two-year postoperative MRI appearances of four-strand, semitendinosus ACL autografts (as measured by SNQ and Howell score) do not appear to have a relationship with postoperative functional scores, instrumented anterior laxity, or patient age at surgery. Other tools for analysis of graft maturity should be developed. Cite this article: Bone Jt Open 2021;2(8):569–575.

Neither Residual Anterior Knee Laxity Up to 6 mm nor a Pivot Glide Predict Patient-Reported Outcome Scores or Subsequent Knee Surgery Between 2 and 6 Years After ACL Reconstruction

Background: A primary goal of anterior cruciate ligament reconstruction (ACLR) is to reduce pathologically increased anterior and rotational laxity of the knee, but the effects of residual laxity on patient-reported outcomes (PROs) after ACLR remain unclear. Hypothesis: Increased residual laxity at 2 years postoperatively is predictive of a higher risk of subsequent ipsilateral knee surgery and decreases in PRO scores from 2 to 6 years after surgery. Study Design: Cohort study; Level of evidence, 2. Methods: From a prospective multicenter cohort, 433 patients aged <36 years were identified at a minimum 2 years after primary ACLR. These patients underwent a KT-1000 arthrometer assessment and pivot-shift test and completed PRO assessments with the Knee injury and Osteoarthritis Outcome Score and International Knee Documentation Committee (IKDC) scores. Patients completed the same PROs at 6 years postoperatively, and any subsequent ipsilateral knee procedures during this period were recorded. Subsequent surgery risk and change in PROs from 2 to 6 years postoperatively were compared based on residual side-to-side KT-1000 arthrometer differences (<−1 mm, −1 to 2 mm, 2 to 6 mm, and >6 mm) in laxity at 2 years postoperatively. Multiple linear regression models were built to determine the relationship between 2-year postoperative knee laxity and 2- to 6-year change in PROs while controlling for age, sex, body mass index, smoking status, meniscal and cartilage status, and graft type. Results: A total of 381 patients (87.9%) were available for follow-up 6 years postoperatively. There were no significant differences in risk of subsequent knee surgery based on residual knee laxity. Patients with a difference >6 mm in side-to-side anterior laxity at 2 years postoperatively were noted to have a larger decrease in PROs from 2 to 6 years postoperatively ( P < .05). No significant differences in any PROs were noted among patients with a difference <6 mm in side-to-side anterior laxity or those with pivot glide (IKDC B) versus no pivot shift (IKDC A). Conclusion: The presence of a residual side-to-side KT-1000 arthrometer difference <6 mm or pivot glide at 2 years after ACLR is not associated with an increased risk of subsequent ipsilateral knee surgery or decreased PROs up to 6 years after ACLR. Conversely, patients exhibiting a difference >6 mm in side-to-side anterior laxity were noted to have significantly decreased PROs at 6 years after ACLR.

Incidence and Risk Factors of Subsequent Meniscal Surgery After Successful Anterior Cruciate Ligament Reconstruction: A Retrospective Study With a Minimum 2-Year Follow-up

Background: One of the goals of anterior cruciate ligament (ACL) reconstruction is a meniscal protective effect on the knee. Despite the advancement of ACL reconstruction techniques, subsequent meniscal tears after ACL reconstruction remain a problem, and the risk factors for recurring lesions are still unclear. Purpose: To investigate the incidence of subsequent meniscal surgery after primary ACL reconstruction without revision ACL surgery and to determine the risk factors associated with this reoperation. Study Design: Case series; Level of evidence, 4. Methods: Overall, 518 patients who underwent primary ACL reconstruction between 2004 and 2012 at one instution participated in this study. Data on body mass index, graft type and femoral tunnel-drilling technique of ACL reconstruction, and location and type of meniscal injury and its treatment at ACL reconstruction were collected from medical records. Clinical outcomes were investigated, including side-to-side difference of anterior laxity, pivot-shift grade, and subsequent meniscal surgery without ACL insufficiency (at minimum 2-year follow-up). Results: The prevalence of tears to the medial meniscus (MM) at the primary ACL reconstruction was 43.6% (226/518), 140 of which were repaired; on the contrary, tears of the lateral meniscus (LM) had a prevalence of 55.8% (289/518), 42 of which were repaired. At a mean 30.3 months (range, 8-124 months) after ACL reconstruction, 20 patients (3.9%; 14 MM tears, 3 LM tears, 3 MM + LM tears) required meniscal surgery without ACL reinjury or recurrence of instability. Of these, 14 MMs and 3 LMs had been repaired at primary ACL reconstruction. The failure rates of repaired MM and LM were 10.0% (14/140) and 7.1% (3/42), respectively. The failure rate of MM repair using the all-inside technique (6/36) was significantly higher compared with no treatment, inside-out repair, or partial resection ( P = .045). In multiple regression analysis, the presence of MM injury at the time of ACL reconstruction (odds ratio [OR], 7.81; P = .003), the side-to-side difference of postoperative anterior tibial translation (OR, 1.91; P = .032), and follow-up period after ACL reconstruction (OR, 1.02; P = .003) were risk factors of subsequent meniscal surgery after ACL reconstruction. Conclusion: Incidence of subsequent meniscal surgery after successful ACL reconstruction was <5%. Presence of MM tear at the time of ACL reconsturuction, small amount of increased anterior laxity, and long-term period after ACL reconstruction were predictive of subsequent meniscal surgery.

Lateral Extra-articular Tenodesis Reduces Anterior Cruciate Ligament Graft Force and Anterior Tibial Translation in Response to Applied Pivoting and Anterior Drawer Loads

Background: The biomechanical effect of lateral extra-articular tenodesis (LET) performed in conjunction with anterior cruciate ligament (ACL) reconstruction (ACLR) on load sharing between the ACL graft and the LET and on knee kinematics is not clear. Purpose/Hypothesis: The purpose was to quantify the effect of LET on (1) forces carried by both the ACL graft and the LET and (2) tibiofemoral kinematics in response to simulated pivot shift and anterior laxity tests. We hypothesized that LET would decrease forces carried by the ACL graft and anterior tibial translation (ATT) in response to simulated pivoting maneuvers and during simulated tests of anterior laxity. Study Design: Controlled laboratory study. Methods: Seven cadaveric knees (mean age, 39 ± 12 years [range, 28-54 years]; 4 male) were mounted to a robotic manipulator. The robot simulated clinical pivoting maneuvers and tests of anterior laxity: namely, the Lachman and anterior drawer tests. Each knee was assessed in the following states: ACL intact, ACL sectioned, ACL reconstructed (using a bone–patellar tendon–bone autograft), and after performing LET (the modified Lemaire technique after sectioning of the anterolateral ligament and Kaplan fibers). Resultant forces carried by the ACL graft and LET at the peak applied loads were determined via superposition. ATT was determined in response to the applied loads. Results: With the applied pivoting loads, performing LET decreased ACL graft force up to 80% (44 ± 12 N; P < .001) and decreased ATT of the lateral compartment compared with that of the intact knee up to 7.6 ± 2.9 mm ( P < .001). The LET carried up to 91% of the force generated in the ACL graft during isolated ACLR (without LET). For simulated tests of anterior laxity, performing LET decreased ACL graft force by 70% (40 ± 20 N; P = .001) for the anterior drawer test with no significant difference detected for the Lachman test. No differences in ATT were deteced between ACLR with LET and the intact knee on both the Lachman and the anterior drawer tests ( P = .409). LET reduced ATT compared with isolated ACLR on the simulated anterior drawer test by 2.4 ± 1.8 mm ( P = .032) but not on the simulated Lachman test. Conclusion: In a cadaveric model, LET in combination with ACLR transferred loads from the ACL graft to the LET and reduced ATT with applied pivoting loads and during the simulated anterior drawer test. The effect of LET on ACL graft force and ATT was less pronounced on the simulated Lachman test. Clinical Relevance: LET in addition to ACLR may be a suitable option to offload the ACL graft and to reduce ATT in the lateral compartment to magnitudes less than that of the intact knee with clinical pivoting maneuvers. In contrast, LET did not offload the ACL graft or add to the anterior restraint provided by the ACL graft during the Lachman test.

Moderately Increased Post-Operative Anterior Knee Laxity does not Predict Decreases in Patient-Reported Outcome Scores or Subsequent Knee Surgery between 2 and 6 Years after ACL reconstruction

Objectives: A primary goal of anterior cruciate ligament reconstruction is to reduce pathologically increased anterior and rotational laxity of the knee. The impact of residual anterior laxity on patient-reported outcomes and the risk of subsequent ipsilateral knee surgery has not been clearly elucidated. The goal of this study is to determine the influence of residual anterior knee laxity on changes in patient-reported outcomes from 2 to 6 years following ACL reconstruction and risk of subsequent ipsilateral knee surgery during that period. Methods: From a prospective multi-center cohort of patients, 429 patients under age 35 years injured in sports with no history of concomitant ligament surgery, revision ACL surgery, or surgery of the contralateral knee were identified at a minimum 2 years following primary ACL reconstruction. These patients underwent a KT-1000 assessment of anterior knee laxity examination relative to the contralateral normal knee by an independent examiner and completed patient-reported outcome assessments with KOOS and IKDC scores. Patients were followed until the 6-year mark following ACL reconstruction and any ipsilateral knee surgeries performed during this period were noted. Patients completed the same patient-reported outcome assessments at 6 years post-operative. Subsequent surgery risk was calculated and compared between those patients with side-to-side KT-1000 differences between -1 and 2 mm and those with a side-to-side KT-1000 differences between 2 and 6mm. Multiple linear regression models were built to determine the relationship between KT-1000 and 2 to 6 year change in patient-reported outcome score while controlling for age, sex, BMI, smoking status, meniscus and cartilage status, and graft type. Results: Thee hundred seventy-seven patients (87.9%) were available for follow-up at the six year mark post-operative. There were 36 patients with a side to side KT-1000 difference less than -1 mm (tighter than contralateral) that were excluded from the analysis. Side-to-side KT-1000 difference was between -1 and 2 mm (IKDC A) in 153 patients, between 2 and 6 mm (IKDC B) in 162 patients, and greater than 6 mm in 26 patients. Subsequent knee surgery was performed significantly more patients in the IKDC A group (23 of 153 patients, 15%) than in the IKDC B group (13 of 162 patients, 8%) (p = 0.05). Increased side-to-side KT-1000 differences at 2-year post-operative were correlated with decreases in subjective IKDC score (β = -0.67, p = 0.038) and KOOS-sport subscale (β = -0.90, p = 0.029) but not with other KOOS subscales. A 5mm increase in anterior laxity at 2 years would predict a 3.4 point decrease in IKDC subjective score and a 4.5 point decrease in the KOOS sport subscale at 6 years post-operative. Conclusion: Three presence of 2 to 6 mm of residual side-to-side KT-1000 difference is not associated with an increased risk of subsequent ipsilateral knee surgery or clinically relevant decrease in patient-reported outcome score up to 6 years following ACL reconstruction.

Impact of Medial Meniscotibial Ligament Disruption Compared to Peripheral Medial Meniscal Tear on Knee Biomechanics

Medial meniscotibial ligament (MTL) lesions may go unrecognized and untreated and have detrimental impact on knee biomechanics and joint pathology. Therefore, this study was designed to compare the biomechanical impact of midbody MTL disruption to corresponding peripheral medial meniscal (PMM) tears in anterior cruciate ligament (ACL) intact and ACL-deficient cadaveric knees. Cadaveric knees (n = 12; 6 matched pairs) were tested for laxity and ACL strain under anterior, valgus, and external rotation loading at 0, 30, and 90 degree of flexion. Knees were randomly assigned to ACL-intact (n = 6) or ACL-deficient (n = 6) groups. Large midbody MTL disruption or corresponding PMM tears were created (n = 3/group) and knees retested. PMM tears were repaired arthroscopically with inside-out suturing, and MTL lesions were repaired with suture anchors via an open approach. Knees were retested after repair. Biomechanical testing data were compared for statistically significant differences. Large MTL and PMM lesions were associated with significant increases in ACL strain, anterior laxity at 0, 30, and 90 degrees (p = 0.006), valgus laxity (p = 0.0012), and external rotation laxity (p = 0.0003) compared with intact knees. Repair of each lesion restored knee stability and reduced ACL strain to intact levels. In ACL-deficient knees, there was significantly increased anterior, valgus, and external rotation laxity compared with the ACL-intact state and MTL and PMM lesions further increased laxity at all angles. However, differences were not statistically significant and repair of meniscal lesions alone did not restore stability to ACL-deficient knees. These results highlight the need to recognize medial MTL injury and perform an appropriate repair procedure to restore knee stability and protect against excessive ACL strain.

Engagement of the Secondary Ligamentous and Meniscal Restraints Relative to the Anterior Cruciate Ligament Predicts Anterior Knee Laxity

Background: Patients with high-grade preoperative side-to-side differences in anterior laxity as assessed via the Lachman test after unilateral anterior cruciate ligament (ACL) rupture are at heightened risk of early ACL graft failure. Biomechanical factors that predict preoperative side-to-side differences in anterior laxity are poorly understood. Purpose: To assess, in a cadaveric model, whether the increase in anterior laxity caused by sectioning the ACL (a surrogate for preoperative side-to-side differences in anterior laxity) during a simulated Lachman test is associated with two biomechanical factors: (1) the tibial translation at which the secondary anterior stabilizers, including the remaining ligaments and the menisci, begin to carry force, or engage, relative to that of the ACL or (2) the forces carried by the ACL and secondary stabilizers at the peak applied anterior load. Study Design: Controlled laboratory study. Methods: Seventeen fresh-frozen human cadaveric knees underwent Lachman tests simulated through a robotic manipulator with the ACL intact and sectioned. The net forces carried by the ACL and secondary soft tissue stabilizers (the medial meniscus and all remaining ligaments, measured as a whole) were characterized as a function of anterior tibial translation. The engagement points of the ACL (with the ACL intact) and each secondary stabilizer (with the ACL sectioned) were defined as the anterior translation at which they began to carry force, or engaged, during a simulated Lachman test. Then, the relative engagement point of each secondary stabilizer was defined as the difference between the engagement point of each secondary stabilizer and that of the ACL. Linear regressions were performed to test each association ( P < .05). Results: The increase in anterior laxity caused by ACL sectioning was associated with increased relative engagement points of both the secondary ligaments (β = 0.87; P < .001; R2 = 0.75) and the medial meniscus (β = 0.66; P < .001; R2 = 0.58). Smaller changes in anterior laxity were also associated with increased in situ medial meniscal force at the peak applied load when the ACL was intact (β = −0.06; P < .001; R2 = 0.53). Conclusion: The secondary ligaments and the medial meniscus require greater anterior tibial translation to engage (ie, begin to carry force) relative to the ACL in knees with greater changes in anterior laxity after ACL sectioning. Moreover, with the ACL intact, the medial meniscus carries more force in knees with smaller changes in anterior laxity after ACL sectioning. Clinical Relevance: Relative tissue engagement is a new biomechanical measure to characterize in situ function of the ligaments and menisci. This measure may aid in developing more personalized surgical approaches to reduce high rates of ACL graft revision in patients with high-grade laxity.

Impact of Surgical Timing on Clinical Outcomes in Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction Using Hamstring Tendon Autografts

Background: To date, no studies have analyzed the influence on clinical outcomes of the interval between an anterior cruciate ligament (ACL) injury and double-bundle (DB) reconstruction with hamstring tendon autografts. Hypotheses: (1) Performing ACL reconstruction sooner after an injury will reduce postoperative anterior and rotatory knee instability, (2) postoperative range of knee motion or functional results will not be affected by different intervals between injury and surgery, and (3) preoperative isokinetic peak torque of the quadriceps and hamstring muscles will be lower in patients undergoing surgery earlier, while postoperative muscle strength will not be affected by surgery timing. Study Design: Cohort study; Level of evidence, 3. Methods: This study was conducted on a total of 171 patients who had undergone anatomic DB ACL reconstruction with hamstring tendon autografts. The patients were divided into 3 groups based on the time to surgery: (1) ≤1 month after the injury (group E; n = 25), (2) between 1 and 3 months after the injury (group M; n = 72), and (3) >3 months after the injury (group D; n = 74). Patients were assessed for a minimum of 2 years after surgery. Results: Concerning postoperative anterior laxity, 1-way analysis of variance demonstrated a significant difference ( P = .0274) among the 3 groups. Anterior laxity was significantly less in group E than in group D ( P = .0206). Spearman rank correlation analysis showed a significant correlation (ρ = 0.200; P = .0327) between anterior knee laxity and time to surgery. Also, a significant correlation ( P = .0461) was found between the degree of the pivot-shift phenomenon and time to surgery. There were no significant differences in loss of knee extension or flexion among the 3 groups, nor were there any differences in the Lysholm knee score or International Knee Documentation Committee grade. Postoperatively, there were no significant differences in peak torque of the quadriceps or hamstring muscles among the 3 groups. Conclusion: Early DB reconstruction led to significantly less anterior laxity compared with delayed reconstruction. There were no significant differences in postoperative range of knee motion or functional results among the 3 time intervals between injury and surgery in this study.

Influence of a posteromedial meniscocpsular injury on the tibiofemoral joint laxity: A cadaveric study

Objectives Up to 61% of meniscal tears can be associated with ACL ruptures. These lesions lead to anterior and rotary laxity increase. Posterior peripheral meniscocaspsular tear of medial meniscus is also called ramp lesion. Prevalence of this kind of lesion is 9% to 17% in adults and up to 23% in pediatric popultation. The aim of this study was to determined anterior laxity of cadaveric ACL deficient knees. Hypothesis was to find a correlation between size of ramp lesion and laxity in order to determine a threshold of size for which reparation is mandatory. Methods Twelve fresh cadaveric knees were explored for the study. Two knees was excluded because they presented major lesions of osteoarthritis and ACL and meniscal tears. 10 remaining knees were from 3 males and 2 females. Mean age at time of death was 86 years old. Dynamic laximetry with GNRB device was made in several conditions: Knee without any intervention, full of water knee, after ACL rupture and after ACL rupture and increasing sizes of ramp lesions up to 30 mm. Anteroposterior laxity was measured at each time with 3 kind of loading charge (134 N, 200 N and 250 N). Results After ACL section only, tibiofemoral joint anterior laxity was significatively increased. Mean increasing was 156% whatever is the loading force. No statistical laxity difference was find between knees with ACL tears only and knees with ACL and meniscal tears for each size of ramp lesions. Increasing size of ramp lesion was not correlated to increasing of laxity. We could not be able to determine a threshold for ramp lesion reparation. Conclusion: GNRB® is a valid device of knee laxity measure, escpecially for ACL deficient knee. Despite use of this performing tool, we can’t confirm our hypothesis. Stephen et al in 2015 have shown, with cadaveric study, significant increase of anterior tibial translation and rotary laxity in knees with extended ramp lesions. There is no data about a ramp lesion size threshold with clinical relevance. GNRB gives reliable measures of laxity in ACL deficient knees. We could not find a threshold size of ramp lesion which increase tibial anterior laxity. Cadaveric rotary laxity has to be also studied to find this threshold.

DO TIBIAL EMINENCE FRACTURES AND ANTERIOR CRUCIATE LIGAMENT TEARS HAVE SIMILAR OUTCOMES?

Background: Avulsion fractures involving the tibial eminence are considered equivalent in etiology to anterior cruciate ligament tears, however there is limited data comparing outcomes of adolescent patients undergoing surgical fixation of tibial eminence fractures to those undergoing anterior cruciate ligament (ACL) reconstruction. Purpose: The purpose of this study was to compare clinical outcomes, subsequent ACL injury rates, and activity levels between adolescent patients who underwent tibial eminence fracture fixation to patients with mid-substance ACL tears who required acute ligament reconstruction. Methods: This study included a group of patients with tibial eminence fractures treated with surgical fixation matched to a group of similar patients with ACL tears treated with reconstruction between the years of 2001 and 2015. Data regarding initial injury, surgical intervention, ACL/ACL graft injury rates, and physical examination findings were recorded. Clinical and functional outcomes were obtained using physical examination, IKDC subjective scores, Lysholm scores, and Tegner Activity levels. Results: Sixty patients with a mean follow-up of 57.7 (24-206) months were included. 20 patients (11 M:9 F) who underwent surgical fixation for tibial eminence fractures (TEF) with a mean age of 11.9 (7-15) years were matched to a group of 40 patients (23 M:17 F) who underwent ACL reconstruction for ACL tears with a mean age of 12.5 (8-15) years. The TEF group demonstrated significantly lower postoperative IKDC (TEF group: 94.0, ACL group: 97.2 (p=0.04)) and Lysholm scores (TEF group: 92.4, ACL group: 96.9 (p=0.02)). The TEF group returned to sport 121 days sooner (p<0.01), but there was no difference in postoperative Tegner scores (TEF group: 7.3, ACL group: 7.6 (p=0.16)). The TEF group demonstrated increased postoperative anterior laxity (p=0.02) and a higher rate of postoperative arthrofibrosis (p=0.04). There was no difference in subsequent ACL injury (p=0.41). Conclusion: Patients with tibial eminence fractures demonstrated lower mean clinical outcome scores compared to patients with ACL tears at minimum 2-year follow up. Additionally, they experienced more postoperative anterior laxity and had a higher rate of postoperative arthrofibrosis. There was no difference in subsequent ACL injury rate. The TEF group returned to sport sooner than the ACL group, but the postoperative activity level was similar.