Risk Of Revision Anterior Cruciate Ligament Reconstruction Research Articles

Poster 314: Hamstring Autograft Diameter Effect on Surgical Outcome in a Prospective ACL Reconstruction Patient Cohort

Objectives: The purpose was to investigate the effect of hamstring autograft diameter on risk of graft failure and subsequent either knee surgery following ACLR in a prospective cohort. Background: Optimization of graft selection and incorporation in anterior cruciate ligament (ACL) reconstruction (ACLR) is an evolving science. Recent studies suggest hamstring tendon autograft diameter may influence outcomes in primary ACLR, with a larger diameter acting as a protective factor against ACL graft rupture. Further evidence using a prospective patient database is valuable in corroborating the association between ACL autograft diameter and patient outcomes. Methods: Prospective data was collected for a cohort of patients undergoing primary ACLR from February 2015 to February 2018. Exclusion criteria included non-hamstring graft selection, allograft augmentation, skeletally immature patients, revision ACLR, prior contralateral ACLR, and multiligament injuries. Cases from 10 fellowship-trained surgeons within a single institution were included. Recorded tunnel size was utilized as a surrogate for autograft diameter. The contribution of age, sex, BMI and operating surgeon on autograft diameter was studied via mixed effect modeling. The effect of hamstring tendon autograft diameter on risk of subsequent surgery was measured using multivariable linear regression modeling that controlled for patient and surgery characteristics including age, sex, BMI, Marx activity score, and graft diameter. Two-year outcomes were collected for incidence of subsequent surgery to either knee, including ipsilateral revision ACLR and contralateral primary ACLR. Results: Of the patients undergoing ACLR with hamstring autograft who met inclusion criteria, there was 90.5% follow up for subsequent surgery outcomes at minimum of 2 years, resulting in 381 patients. Female sex and lower BMI was associated with smaller autograft diameter and operating surgeon had a significant effect on autograft diameter. 59 patients (15.5%) had subsequent ipsilateral surgery and 27 patients (7.09%) had revision ACLR within 2 years. 29 patients (7.61%) had contralateral subsequent knee surgery and 20 patients (5.25%) had primary contralateral ACLR within 2 years. After controlling for age, sex, BMI, and baseline Marx activity score, hamstring autograft diameter was not associated with risk of all ipsilateral subsequent knee surgery (odds ratio (OR) 0.87, 95% confidence interval (CI) 0.56 - 1.36, p = 0.536). Baseline Marx score greater than or equal to 12 was associated with risk of all ipsilateral subsequent knee surgery with OR 2.55 (CI 1.41 – 4.59, p = 0.002). After controlling for age, sex and BMI, hamstring autograft diameter was not associated with risk of revision ACLR (OR 0.71, CI 0.38 - 1.33, p = 0.286). Age was associated with risk of ipsilateral revision ACLR with OR 0.16 (CI 0.05 – 0.51, p = 0.002). After controlling for age, sex and BMI, hamstring autograft diameter was not associated with risk of all contralateral subsequent knee surgery (OR 0.89, CI 0.50 - 1.59, p = 0.703) including contralateral ACLR (OR 0.78, CI 0.39 - 1.59, p = 0.501). Age was found to be a significant prognostic variable of contralateral ACLR with OR 0.30 (CI 0.10 – 0.93, p = 0.037). No variables within the model were associated with risk of all contralateral subsequent surgery events. Conclusions: Hamstring autograft diameter greater than 8mm was not associated with risk of revision ACLR or other subsequent surgery in the ipsilateral or contralateral knee in a multivariable logistic regression analysis of a prospective patient cohort. Lower age was associated with risk of ipsilateral revision ACLR and contralateral ACLR. Baseline Marx activity score greater than or equal to 12 was associated with risk of all subsequent ipsilateral knee surgery. [Table: see text][Table: see text][Table: see text][Table: see text]

Incidence and risk factors for revision and contralateral anterior cruciate ligament reconstruction: A population-based retrospective cohort study.

There is a limited data on epidemiology of primary and recurrent anterior cruciate ligament reconstruction (ACLR) in Canada. The objectives of this study were to examine the incidence and factors associated with recurrent ACLR (revision and contralateral ACLR) in a western Canadian province of Alberta. We conducted a retrospective cohort study with an average follow up of 5.7 years. Albertans aged 10 to 60 years with a history of primary ACLR between 2010/11 to 2015/16 were included in the study. Participants were followed up until March 2019 to observe outcomes: Ipsilateral revision ACLR and contralateral ACLR. Kaplan Meir approach was used to estimate event free survival and Cox proportional hazard regression analysis was conducted to identify associated factors. Of the total participants with a history of primary ACLR on a single knee (n = 9292), n = 359, 3.9% (95% confidence interval: 3.5-4.3) underwent a revision ACLR. A similar proportion among those having primary ACLR on either knee (n = 9676), n = 344, 3.6% (95% confidence interval: 3.2-3.9) underwent a contralateral primary ACLR. Young age (<30 years) was associated with increased risk of contralateral ACLR. Similarly, young age (<30 years), having initial primary ACLR in winter and having allograft were associated with a risk of revision ACLR. Clinicians can use these findings in their clinical practice and designing rehabilitation plans as well as to educate patients about their risk for recurrent anterior cruciate ligament tear and graft failure.

LOWER RISK OF REVISION WITH SUSPENSORY TIBIAL FIXATION VERSUS INTERFERENCE TIBIAL FIXATION OF HAMSTRING TENDON AUTOGRAFTS IN ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

The optimal method of tibial fixation when using a hamstring tendon autograft in anterior cruciate ligament (ACL) reconstruction is unclear. This study aimed to compare the risk of revision ACL reconstruction between suspensory and interference devices on the tibial side.Prospective data on primary ACL reconstructions recorded in the New Zealand ACL Registry between April 2014 and December 2019 were analyzed. Only patients with a hamstring tendon autograft fixed with a suspensory device on the femoral side were included. The rate of revision ACL reconstruction was compared between suspensory and interference devices on the tibial side. Univariate Chi-Square test and multivariate Cox regression was performed to compute hazard ratios (HR) and 95% confidence intervals (CI) with adjustment for age, gender, time-to-surgery, activity at the time of injury, number of graft strands and graft diameter.6145 cases were analyzed, of which 59.6% were fixed with a suspensory device on the tibial side (n = 3662), 17.6% fixed with an interference screw with a sheath (n = 1079) and 22.8% fixed with an interference screw without a sheath (n = 1404). When compared to suspensory devices (revision rate = 3.4%), a higher risk of revision was observed when using an interference screw with a sheath (revision rate = 6.2%, adjusted HR = 2.05, 95% CI 1.20 – 3.52, p = 0.009) and without a sheath (revision rate = 4.6%, adjusted HR = 1.81, 95% CI 1.02 – 3.23, p = 0.044). The number of graft strands and a graft diameter of ≥8 mm did not influence the risk of revision.When reconstructing the ACL with a hamstring tendon autograft, the use of an interference screw, with or without a sheath, on the tibial side has a higher risk of revision when compared to a suspensory device.

Suspensory Versus Interference Tibial Fixation of Hamstring Tendon Autografts in Anterior Cruciate Ligament Reconstruction: Results From the New Zealand ACL Registry

Background: The hamstring tendon is frequently used to reconstruct the anterior cruciate ligament (ACL), but there is a lack of consensus on the optimal method of fixation. Registry studies have shown that the type of femoral fixation device can influence the risk of revision ACL reconstruction (ACLR), but it is unclear whether the type of tibial fixation has an effect. In New Zealand, over 95% of hamstring tendon grafts are fixed with an adjustable loop suspensory device on the femoral side, with variable usage between suspensory and interference devices, with or without a sheath, on the tibial side. Purpose: To investigate the association between the type of tibial fixation device and the risk of revision ACLR. Study Design: Cohort Study; Level of evidence, 2. Methods: Prospective data recorded in the New Zealand ACL Registry were analyzed. Only primary ACLRs performed with a hamstring tendon autograft fixed with a suspensory device on the femoral side were included. A Cox regression survival analysis with adjustment for patient factors was performed to analyze the effects of the type of tibial fixation device, the number of graft strands, and graft diameter on the risk of revision. Results: A total of 6145 primary ACLRs performed between 2014 and 2019 were analyzed. A total of 59.6% of hamstring tendon autografts were fixed with a suspensory device on the tibial side (n = 3662), 17.6% with an interference screw with a sheath (n = 1079), and 22.8% with an interference screw without a sheath (n = 1404). When compared with suspensory devices, a higher revision risk was observed when using an interference screw with a sheath (adjusted hazard ratio [HR], 2.05; P = .009) and without a sheath (adjusted HR, 1.81; P = .044). The number of graft strands and a graft diameter of ≥8 mm were associated with the rate of revision on the univariate analysis; however, after adjusting for confounding variables on the multivariate analysis, they did not significantly influence the risk of revision. Conclusion: In this study of hamstring tendon autografts fixed with an adjustable loop suspensory device on the femoral side during primary ACLR, the use of an interference screw, with or without a sheath, on the tibial side resulted in a higher revision rate when compared with a suspensory device.

Delaying ACL reconstruction beyond 6 months from injury impacts likelihood for clinically significant outcome improvement

BackgroundThe effect of surgical latency on outcomes of anterior cruciate ligament reconstruction (ACLR) is a topic that is heavily debated. Some studies report increased benefit when time from injury to surgery is decreased while other studies report no benefit. The purpose of our analysis was to compare achievement of clinically significant outcomes (CSOs) in patients with greater than six months of time from injury to ACLR to those with less than or equal to six months of time to surgery. MethodsPatients undergoing primary ACLR between January 2017 and January 2018 with minimum one year follow-up were included. International Knee Documentation Committee (IKDC) score and Knee Injury and Osteoarthritis Outcomes Score (KOOS) were collected. Multivariate logistic regression was performed for outcome achievement and risk of revision ACLR and Weibull parametric survival analysis was performed for relative time to outcome achievement. The level of significance was set at α = 0.05. Results379 patients were included of which, 140 patients sustained ACL injury greater than six months prior to surgery. This group of patients experienced reduced likelihood to achieve patient-acceptable symptomatic state (PASS) on the IKDC (p = 0.03), KOOS Pain (p = 0.01) and a greater likelihood to undergo revision ACLR (p = 0.001). There was no impact of surgical timing on minimal clinically important difference (MCID). ConclusionPatients with greater than 6 months from injury to ACLR reported reduced likelihood to achieve CSOs, delayed achievement of CSOs, and increased rates of revision surgery.

Risk Factors for Failure After Anterior Cruciate Ligament Reconstruction in a Pediatric Population: A Prediction Algorithm.

Background:Anterior cruciate ligament reconstruction (ACLR) in pediatric patients is becoming increasingly common. There is growing yet limited literature on the risk factors for revision in this demographic.Purpose:To (1) determine the rate of pediatric revision ACLR in a nationally representative sample, (2) ascertain the associated patient- and injury-specific risk factors for revision ACLR, and (3) examine the differences in the rate and risks of revision ACLR between pediatric and adult patients.Study Design:Case-control study; Level of evidence, 3.Methods:The PearlDiver patient record database was used to identify adult patients (age ≥20 years) and pediatric patients (age <20 years) who underwent primary ACLR between 2010 and 2015. At 5 years postoperatively, the risk of revision ACLR was compared between the adult and pediatric groups. ACLR to the contralateral side was also compared. Multivariate logistic regression was used to determine the significant risk factors for revision ACLR and the overall reoperation rates in pediatric and adult patients; from these risk factors, an algorithm was developed to predict the risk of revision ACLR in pediatric patients.Results:Included were 2055 pediatric patients, 1778 adult patients aged 20 to 29 years, and 1646 adult patients aged 30 to 39 years who underwent ACLR. At 5 years postoperatively, pediatric patients faced a higher risk of revision surgery when compared with adults (18.0 % vs 9.2% [adults 20-29 years] and 7.1% [adults 30-39 years]; P < .0001), with significantly decreased survivorship of the index ACLR (P < .0001; log-rank test). Pediatric patients were also at higher risk of undergoing contralateral ACLR as compared with adults (5.8% vs 1.6% [adults 20-29 years] and 1.9% [adults 30-39 years]; P < .0001). Among the pediatric cohort, boys (odds ratio [OR], 0.78; 95% CI, 0.63-0.96; P = .0204) and patients >14 years old (OR, 0.62; 95% CI, 0.45-0.86; P = .0035) had a decreased risk of overall reoperation; patients undergoing concurrent meniscal repair (OR, 1.84; 95% CI, 1.43-2.38; P < .0001) or meniscectomy (OR, 2.20; 95% CI, 1.72-2.82; P < .0001) had an increased risk of revision surgery. According to the risk algorithm, the highest probability for revision ACLR was in girls <15 years old with concomitant meniscal and medial collateral ligament injury (36% risk of revision).Conclusion:As compared with adults, pediatric patients had an increased likelihood of revision ACLR, contralateral ACLR, and meniscal reoperation within 5 years of an index ACLR. Families of pediatric patients—especially female patients, younger patients, and those with concomitant medial collateral ligament and meniscal injuries—should be counseled on such risks.

Outcomes of Anterior Cruciate Ligament Reconstruction in Obese and Overweight Patients: A Systematic Review.

To evaluate the mechanism of injury, outcomes, and complications of anterior cruciate ligament (ACL) reconstruction in overweight and obese patients. MEDLINE, EMBASE, and OVID electronic libraries were systematically searched from inception to December, 2017 for any eligible articles using a combination of the phrases "anterior cruciate ligament," "ACL," "overweight," "obese," and "BMI." Studies that evaluated patients with primary ACL reconstruction, classified patients as overweight or obese, and reported a minimum of 1-year follow-up data were included. Eight cohorts from 9 studies fulfilled the inclusion criteria. There were no significant differences for mechanism of injury, Lysholm scores, Knee injury and Osteoarthritis Outcome Scores values, or return to sports with a body mass index (BMI) above or below 25 kg/m. A significant difference was described in International Knee Documentation Committee (IKDC) scores when comparing obese patients (BMI >30 kg/m) to patients with BMI <25 kg/m (P <0.01). In patients with BMI >25 kg/m, the risk for arthritis was significantly higher but the risk for revision surgery or contralateral ACL tear was lower (P <0.05). There was no significant difference in complication rates (P = 0.77). Patient-reported outcome measures were similar for patients with BMI above and below 25 kg/m, but there is evidence that obese patients have lower IKDC scores. There is a consistent association between overweight status and developing arthritis among patients having an ACL reconstruction. Overweight and obese patients have a lower risk of revision ACL reconstruction and contralateral ACL tear. There is insufficient data to make any conclusions regarding mechanism of injury or complications. More research is needed to better understand what is the appropriate counsel and treatment for overweight or obese patients with ACL tears. CRD42017055594.

Effect of High-Grade Preoperative Knee Laxity on 6-Year Anterior Cruciate Ligament Reconstruction Outcomes

Background: Knee laxity in the setting of anterior cruciate ligament (ACL) injury is often assessed through physical examination using the Lachman, pivot shift, and anterior drawer tests. The degree of laxity noted on these examinations may influence treatment decisions and prognosis. Hypothesis: Increased preoperative knee laxity is associated with increased risk of revision ACL reconstruction, increased risk of contralateral ACL reconstruction, and poorer patient-reported outcomes at 6 years postoperatively. Study Design: Cohort study; Level of evidence, 2. Methods: 2333 patients who underwent primary isolated ACL reconstruction without additional ligament injury were identified. Patients reported by the operating surgeons to have an International Knee Documentation Committee (IKDC) grade D Lachman, anterior drawer, or pivot shift examination were classified as having a high-grade laxity. Multiple logistic regression models were used to evaluate whether having high-grade preoperative laxity was predictive of increased odds of undergoing subsequent revision or contralateral ACL reconstruction within 6 years of the index procedure, controlling for patient age, sex, body mass index, Marx activity level, sport, graft type, medial meniscal treatment, and lateral meniscal treatment. Multiple linear regression modeling was used to evaluate whether having high-grade preoperative laxity was predictive of poorer IKDC or Knee injury and Osteoarthritis Outcome Score Knee-Related Quality of Life (KOOS-QOL) scores at 6 years postoperatively, after controlling for baseline score, patient age, ethnicity, sex, body mass index, marital status, smoking status, sport participation, competition level, Marx activity rating score, graft type, and articular cartilage and meniscal status. Results: In total, 743 of 2325 patients (32.0%) were noted to have high-grade laxity on at least 1 physical examination test. High-grade Lachman was noted in 334 patients (14.4%), high-grade pivot shift was noted in 617 patients (26.5%), and high-grade anterior drawer was noted in 233 patients (10.0%). Six-year revision and contralateral ACL reconstruction data were available for 2129 patients (91.6%). High-grade prereconstruction Lachman was associated with significantly increased odds of ACL graft revision (odds ratio [OR], 1.76; 95% CI, 1.10-2.80, P = .02) and contralateral ACL reconstruction (OR, 1.68; 95% CI, 1.09-2.69; P = .019). High-grade prereconstruction pivot shift was associated with significantly increased odds of ACL graft revision (OR, 1.75; 95% CI, 1.19-2.54, P = .002) but not with significantly increased odds of contralateral ACL reconstruction (OR, 1.30; 95% CI, 0.89-1.87; P = .16). High-grade prereconstruction laxity was associated with statistically significantly lower 6-year IKDC (β = −2.26, P = .003), KOOS-QOL (β = −2.67, P = .015), and Marx activity scores (β = −0.54, P = .020), but these differences did not approach clinically relevant differences in patient-reported outcomes. Conclusion: High-grade preoperative knee laxity is predictive of increased odds of revision ACL reconstruction and contralateral ACL reconstruction 6 years after ACL reconstruction. Poorer patient-reported outcome scores in the high-grade laxity group were also noted, but the difference did not reach a level of clinical relevance.

Graft fixation influences revision risk after ACL reconstruction with hamstring tendon autografts

Background and purpose — A large number of fixation methods of hamstring tendon autograft (HT) are available for anterior cruciate ligament reconstruction (ACLR). Some studies report an association between fixation method and the risk of revision ACLR. We compared the risk of revision of various femoral and tibial fixation methods used for HT in Scandinavia 2004–2011.Materials and methods — A register-based study of 38,666 patients undergoing primary ACLRs with HT, with 1,042 revision ACLRs. The overall median follow-up time was 2.8 (0–8) years. Fixation devices used in a small number of patients were grouped according to design and the point of fixation.Results — The most common fixation methods were Endobutton (36%) and Rigidfix (31%) in the femur; and interference screw (48%) and Intrafix (34%) in the tibia. In a multivariable Cox regression model, the transfemoral fixations Rigidfix and Transfix had a lower risk of revision (HR 0.7 [95% CI 0.6–0.8] and 0.7 [CI 0.6–0.9] respectively) compared with Endobutton. In the tibia the retro interference screw had a higher risk of revision (HR 1.9 [CI 1.3–2.9]) compared with an interference screw.Interpretation — The choice of graft fixation influences the risk of revision after primary ACLR with hamstring tendon autograft.

Age-Related Risk Factors for Revision Anterior Cruciate Ligament Reconstruction

Background: It is not clear whether risk factors for revision anterior cruciate ligament reconstruction (ACLR) are the same throughout patients’ lives. Purpose: To assess (1) the risk of revision ACLR by age and (2) age-specific risk factors for revision ACLR. Study Design: Cohort study; Level of evidence, 2. Methods: A cohort study using patients having undergone primary ACLR who were registered in the Kaiser Permanente ACLR Registry (February 2005 to June 2013) was conducted. Aseptic revision was the main endpoint. Age was evaluated as a risk factor for revision. The cohort was stratified into 4 age groups: <21, 21-30, 31-40, and >40 years. Graft type, sex, body mass index (BMI), and race were assessed as revision risk factors within each group. Survival analyses were conducted. Results: Of the 21,304 patients evaluated, 7026 (33%) patients were aged <21 years, 5762 (27%) were 21-30 years, 4656 (22%) were 31-40 years, and 3860 (18%) were >40 years. Allografts were used in 8671 (41%) patients, hamstring autografts in 6823 (32%), and bone–patellar tendon–bone (BPTB) autografts in 5260 (25%). The 5-year revision probability was highest in patients <21 years old (9.0%; 95% CI, 8.0%-10.1%) and lowest in those >40 years old (1.9%; 95% CI, 1.3%-2.7%). Compared with patients aged >40 years, the adjusted revision risk for patients aged <21 years was 7.76 (95% CI, 5.52-10.90). In patients aged <21 years, a lower revision risk was seen in female patients (hazard ratio [HR], 0.76; 95% CI, 0.61-0.93) compared with male patients, patients with a BMI of 30-35 kg/m2 (HR, 0.75; 95% CI, 0.59-0.95) and BMI >35 kg/m2 (HR, 0.49; 95% CI, 0.34-0.70) compared with those with a BMI <30 kg/m2, and black patients (HR, 0.55, 95% CI, 0.36-0.85) compared with white patients. Sex, BMI, and race were not associated with the risk of revision in older patients. In patients ≤40 years old, those with allografts had a higher risk of revision than those with BPTB autografts (HR, 2.69, 2.35, and 3.04 for patients aged <21, 21-30, and 31-40 years, respectively). Patients <21 years old with hamstring autografts had a 1.61 times (95% CI, 1.20-2.17) higher risk of revision than did patients with BPTB autografts; these differences were not identified in older patients. Conclusion: Age at the time of ACLR surgery is a strong risk factor for revision ACLR. Other risk factors for revision ACLR, such as graft type, sex, race, and BMI, may vary in strength and significance over a patient’s life. Understanding the age-related risk factors associated with revision ACLR may help with appropriate patient counseling and optimal graft choice when performing ACLR.

Effect of High-Grade Pre-operative Knee Laxity on Outcomes of Anterior Cruciate Ligament Reconstruction

Objectives:Knee laxity in the setting of suspected anterior cruciate ligament (ACL) injury is frequently assessed through physical examination using the Lachman, pivot-shift, and anterior drawer tests. The degree of laxity noted on these examinations may influence treatment decisions and prognosis. We hypothesized that increased pre-operative knee laxity (Grade 3+ pivot-shift, Lachman > 10mm, or anterior drawer greater than 10mm) are associated with increased risk of revision ACL reconstruction and poorer patient-reported outcomes at two years post-operative.Methods:From an ongoing prospective cohort study, 1394 patients that underwent primary isolated ACL reconstruction within 3 months of injury with autograft tissue without medial collateral, lateral collateral, or posterior cruciate injury requiring treatment or prior contralateral ACL injury were identified. Demographic data, physical examination findings under anesthesia at the time of ACL reconstruction, information regarding meniscus status and treatment, and pre-operative and 2 year post-operative International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Outcome Score Knee Related Quality of Life subscale (KOOS-QOL), and Marx activity scores were collected. Patients reported by the operating surgeons as having a Lachman or anterior drawer examination at least 10mm greater than the contralateral side were classified as having a high grade Lachman or anterior drawer respectively. Patients reported by the operating surgeon as having a 3+ pivot-shift were classified as having a high-grade pivot-shift. Patients demonstrating high-grade laxity on any of these examinations were classified as having high-grade pre-operative knee laxity. Multiple logistic regression modeling was used to evaluate whether having high-grade pre-operative laxity was associated with increased odds of undergoing revision ACL reconstruction within 2 years of the index procedure, controlling for patient age, sex, activity level, and graft type. Multiple linear regression modeling was used to evaluate whether having high-grade pre-operative laxity was associated with poorer IKDC or KOOS-QOL scores at 2 years post-operative, controlling for patient age, sex, BMI, and smoking status, baseline score, activity level, graft type, and the presence and treatment of meniscal tears.Results:Two year revision data were available for 1333 patients (95.4%) and patient-reported outcomes were available for 1205 patients (86.4%). High-grade pre-operative laxity was noted in 395 patients (29.6%), including high grade pivot-shift in 24.9%, high-grade Lachman in 11.5%, and high-grade anterior drawer in 8.1%. ACL graft revision was performed in 59 patients (4.4%). The mean post-operative IKDC score was 84.1 ± 14.4 and the mean KOOS-QOL score was 75.1 ± 20.4. The presence of high grade pre-laxity was not associated with increased odds of ACL graft revision (OR=1.47, 95% CI: 0.85 - 2.55, p = 0.17). Similarly, the presence of high-grade pre-laxity was not associated with any difference in post-operative IKDC (β = -0.33, p = 0.71) or KOOS-QOL (β = -0.51, p = 0.70).Conclusion:The presence of high-grade pre-operative knee laxity as assessed by physical examination under anesthesia (Grade 3+ pivot-shift, Lachman > 10mm, or anterior drawer greater than 10mm) is not associated increased odds of revision ACL surgery or poorer patient-reported outcome scores at 2 years following ACL reconstruction.

Smaller Graft Size is Associated with Poorer Outcomes and Increased Risk of Revision 2 Years After Primary ACL Reconstruction with Hamstring Autograft: A MOON Cohort Study

Smaller hamstring autograft size is correlated with lower KOOS and subjective IKDC scores two years following ACL reconstruction and graft size less than 8.5 mm is associated increased risk of revision ACL reconstruction, especially in younger patients. Hamstring autografts are frequently utilized for anterior cruciate ligament (ACL) reconstruction. Commonly used 4-strand grafts average about 8 mm in diameter but significant variation among patients has been noted. Previous retrospective studies have demonstrated increased failure rates with smaller grafts, particularly in younger patients. No studies have evaluated the effect of graft size on patient-reported outcomes following ACL reconstruction. We hypothesize that decreased hamstring autograft size is associated with poorer patient reported outcome scores and increased risk of revision ACL reconstruction. Through use of prospectively collected cohort data augmented with retrospective chart review, 263 of 320 consecutive patients (82.2%) undergoing primary ACL reconstruction with hamstring autograft at two academic centers were evaluated. Graft size, patient sex, femoral tunnel drilling technique, patient age and BMI at the time of ACL reconstruction, pre-operative and 2-year post-operative KOOS and IKDC scores, and whether each patient underwent revision ACL reconstruction during the 2 year follow-up period were recorded. The 263 patients included 144 males (54.8%) and ranged in age from 13 to 58 years (mean, 25.6 years). After controlling for age, sex, operative side, surgeon, BMI, and femoral tunnel drilling technique, a 1mm decrease in ACL graft size predicted a decrease the in KOOS-pain subscale by 3.0 points (p = 0.009), a decrease in the KOOS-sport/recreation function subscale by 4.6 points (p = 0.015), and a decrease in the subjective IKDC score by 2.9 points (p = 0.05). Fifteen of the 263 patients (5.7%) underwent revision ACL reconstruction. Two revisions were performed in the 178 patients over age 18 (1.1%), but 13 revisions were required in the 85 patients age 18 and under (15.3%) (p < 0.0001). Revision was required in 0 of 61 patients (0.0%) with grafts greater than 8mm in diameter and 14 of 202 patients (6.5%) with 8 mm or smaller grafts (p = 0.037). Among patients age 18 and under, revision was required in 0 of 14 patients (0.0%) with grafts greater than 8mm in diameter and 13 of 71 patients (18.3 %) with 8 mm or smaller grafts. Most failures (13 of 15) were noted to occur in patients age 18 and under with grafts 8mm in diameter or less. The revision rate in this population was 18.3% (13 of 71 patients). Smaller hamstring autograft size is a predictor of poorer patient-reported outcome scores 2 years following primary ACL reconstruction. Larger sample size is required to confirm the relationship between smaller graft size and increased risk of revision ACL reconstruction.

Risk factors for Recurrent Anterior Cruciate Ligament Reconstruction: A Population Study in Ontario, Canada with 5-year Follow-up

Objectives:Anterior cruciate ligament reconstruction (ACLR) is routinely performed to treat symptomatic instability. Despite being a common procedure, significant variation persists in technique and graft choice. How patient, provider and surgical factors influence the risk of revision or contralateral primary ACLR has not been investigated using administrative data. The goal of our study was to define the rate and risk factors for ACL re-operation in Ontario.Methods:All primary elective ACLR performed in Ontario, Canada from July 2003 to March 2008 in patients aged 15 to 60 years were identified via billing, diagnosis and procedural databases. The main outcomes were revision and contralateral ACLR, sought until January 2012. Patient factors (age, gender, co-morbidity, income quintile, and length of index hospital admission), provider factors (surgeon volume, academic hospital status) and surgical factors (allograft vs. autograft; fixation: screw, button, staple; concomitant operative procedures) were used as covariates in a Cox Proportional Hazards survivorship model to generate Hazard Ratios (HR) with confidence intervals (alpha 0.05). Kaplan-Meier survivorship curves to revision were generated.Results:A total of 12,967 ACLR with a mean follow-up of 5.2 years were identified. The revision rate was 2.6% [after a median 2.72 years (interquartile range 1.38, 4.11)]. The rate of primary contralateral ACLR was 4.6% [after a median 2.71 years (interquartile range 1.49, 4.22)]. In the Cox model, younger age [15-19 years; HR=2.1 (95% CI: 1.5-2.9), p<0.001], ACLR performed at an academic hospital [HR=1.6 (95% CI: 1.2-2.1), p<0.001] and the use of allograft [HR=1.7 (95% CI: 1.1-2.6), p=0.02] significantly increased the risk of revision ACLR. The K-M curves to revision ACLR for allograft and autograft demonstrated equivalent survivorship for approximately 3 years, after which allograft ACLR were more commonly revised (Figure 1). Only younger age [15-19 years; HR=2.1, (95% CI: 1.6-2.7), p<0.001] was associated with an increased risk of contralateral ACLR.Conclusion:Contralateral ACLR was more frequent than revision ACLR in this population, while both re-operations were significantly more common in patients <20 years old. Academic hospital status but not surgeon volume, and the use of allograft also increased the risk of revision ACLR. Late failure of allograft ACLR is a novel finding.

Incidence and Outcome After Revision Anterior Cruciate Ligament Reconstruction

Background: Revision anterior cruciate ligament (ACL) reconstruction is poorly described because of its rare incidence and mainly small case series presented in the literature. The Danish ACL reconstruction registry has monitored the development in revision ACL reconstruction since 2005. Hypothesis: We hypothesized that younger patients had a higher risk of revision ACL reconstruction than older patients and that subjective clinical outcome was worse after revision ACL reconstruction than after primary ACL reconstruction. Study Design: Cohort study; Level of evidence, 2. Methods: All clinics performing ACL reconstructions in Denmark report to the national ACL reconstruction registry. The revision rate after primary ACL reconstruction (n = 12,193 procedures) and re-revision rate after revision ACL reconstruction (n = 1099 procedures) were calculated for the period of 2005 to 2010. Outcome at 1-year follow-up for the revision cohort was reported using the Knee Injury and Osteoarthritis Outcome Score (KOOS), Tegner function score, and objective knee stability measurement. Results: The rate of revision ACL reconstruction was 4.1% after 5 years. Revision occurred most frequently after 1 to 2 years. Patients below 20 years of age at the time of primary ACL reconstruction had a higher risk of revision (8.7%) than did patients older than 20 years of age (2.8%) (adjusted relative risk, 2.58; 95% confidence interval, 2.02-3.30). The KOOS scores 1 year after revision ACL reconstruction (mean ± standard deviation) were 73 ± 18 for symptoms, 78 ± 17 for pain, 84 ± 16 for activities of daily living, 52 ± 28 for sports, and 48 ± 21 for quality of life. All these scores were significantly lower than for primary ACL reconstruction: 77 ± 17 for symptoms, 84 ± 15 for pain, 89 ± 13 for activities of daily living, 62 ± 25 for sports, and 59 ± 21 for quality of life. Side-to-side difference in knee laxity improved from 5.8 mm before revision ACL reconstruction to 1.9 mm 1 year after revision ACL surgery. The use of allograft tissue for the revision procedure resulted in a higher risk of re-revision than did autograft tissue (relative risk, 2.05; 95% confidence interval, 1.5-2.4) (P < .01). The rate of re-revision after 5 years was 5.4%. Conclusion: In this observational population-based study, the 5-year revision ACL reconstruction rate was 4.1%. Despite achieving acceptable knee stability after revision ACL reconstruction, subjective outcome is less favorable than after primary ACL reconstruction.