Christopher C. Kaeding

Allograft Versus Autograft Anterior Cruciate Ligament Reconstruction: Predictors of Failure From a MOON Prospective Longitudinal Cohort.

Background: Tearing an anterior cruciate ligament (ACL) graft is a devastating occurrence after ACL reconstruction (ACLR). Identifying and understanding the independent predictors of ACLR graft failure is important for surgical planning, patient counseling, and efforts to decrease the risk of graft failure. Hypothesis: Patient and surgical variables will predict graft failure after ACLR. Study Design: Prospective cohort study. Methods: A multicenter group initiated a cohort study in 2002 to identify predictors of ACLR outcomes, including graft failure. First, to control for confounders, a single surgeon’s data (n = 281 ACLRs) were used to develop a multivariable regression model for ACLR graft failure. Evaluated variables were graft type (autograft vs allograft), sex, age, body mass index, activity at index injury, presence of a meniscus tear, and primary versus revision reconstruction. Second, the model was validated with the rest of the multicenter study’s data (n = 645 ACLRs) to evaluate the generalizability of the model. Results: Patient age and ACL graft type were significant predictors of graft failure for all study surgeons. Patients in the age group of 10 to 19 years had the highest percentage of graft failures. The odds of graft rupture with an allograft reconstruction are 4 times higher than those of autograft reconstructions. For each 10-year decrease in age, the odds of graft rupture increase 2.3 times. Conclusion: There is an increased risk of ACL graft rupture in patients who have undergone allograft reconstruction. Younger patients also have an increased risk of ACL graft failure. Clinical Relevance: Given these risks for ACL graft rupture, allograft ACLRs should be performed with caution in the younger patient population.

Risk of Tearing the Intact Anterior Cruciate Ligament in the Contralateral Knee and Rupturing the Anterior Cruciate Ligament Graft During the First 2 Years After Anterior Cruciate Ligament Reconstruction A Prospective MOON Cohort Study

Background The risk of tear of the intact anterior cruciate ligament in the contralateral knee after anterior cruciate ligament reconstruction of the opposite knee and the incidence of rupturing the anterior cruciate ligament graft during the first 2 years after surgery have not been extensively studied in a prospective manner. Clinicians have hypothesized that the opposite normal knee is at equal or increased risk compared with the risk of anterior cruciate ligament graft rupture in the operated knee. Hypothesis The risk of anterior cruciate ligament graft rupture and contralateral normal knee anterior cruciate ligament rupture at 2-year follow-up is equal. Study Design Cohort study; Level of evidence, 2. Methods The Multicenter Orthopaedic Outcome Network (MOON) database of a prospective longitudinal cohort of anterior cruciate ligament reconstructions was used to determine the number of anterior cruciate ligament graft ruptures and tears of the intact anterior cruciate ligament in the contralateral knee at 2-year follow-up. Two-year follow-up consisted of a phone interview and review of operative reports. Results Two-year data were obtained for 235 of 273 patients (86%). There were 14 ligament disruptions. Of these, 7 were tears of the intact anterior cruciate ligament in the contralateral knee (3.0%) and 7 were anterior cruciate ligament graft failures (3.0%). Conclusion The contralateral normal knee anterior cruciate ligament is at a similar risk of anterior cruciate ligament tear (3.0%) as the anterior cruciate ligament graft after primary anterior cruciate ligament reconstruction (3.0%).

The Prognosis and Predictors of Sports Function and Activity at Minimum 6 Years After Anterior Cruciate Ligament Reconstruction A Population Cohort Study

Background: The predictors of anterior cruciate ligament reconstruction (ACLR) outcome at 6 years as measured by validated patient-based outcome instruments are unknown. Hypothesis: Certain variables evaluated at the time of ACLR will predict return to sports function (as measured by the International Knee Documentation Committee [IKDC] questionnaire and the Knee injury and Osteoarthritis Outcome Score [KOOS] Sports and Recreation subscale), knee-related quality of life (KOOS Knee Related Quality of Life subscale), and activity level (Marx Activity Scale). Potential predictor variables include demographic factors, surgical technique and graft choice for ACLR, and intra-articular injuries and treatment. Study Design: Cohort study; Level of evidence, 2. Methods: All patients with unilateral ACLRs from 2002 currently enrolled in the MOON (Multicenter Orthopaedic Outcomes Network) cohort were evaluated. Patients completed the validated outcome instruments preoperatively. Physicians documented intra-articular pathologic abnormalities, treatment, and surgical techniques used at the time of surgery. At 2 and 6 years postoperatively, patients completed the same validated outcome instruments. Results: Follow-up was obtained at 2 years (88%) and at 6 years (84%). The cohort was 57% male with a median age of 23 years at enrollment. The ability to perform sports function was maintained at 6 years, but the Marx activity level continued to decline from baseline. Revision ACLR and use of allograft predicted worse outcomes on the IKDC and both KOOS subscales. Lateral meniscus treatment, smoking status, and body mass index at baseline were each predictors on 2 of 3 scales. The predictors of lower activity level were revision ACLR and female sex. Conclusion: Six years after ACLR, patients could perform sports-related functions and maintain a high knee-related quality of life similar to their 2-year level, although their physical activity level (Marx) dropped over time. Choosing autograft rather than allograft, not smoking, and having normal body mass index are advised to improve long-term outcomes.

Activity Level and Graft Type as Risk Factors for Anterior Cruciate Ligament Graft Failure A Case-Control Study

Background Anterior cruciate ligament (ACL) graft failure is an uncommon but devastating event after reconstruction, and risk factors for graft failure are not well understood. Hypothesis Returning to a high activity level after ACL reconstruction and use of an allograft are risk factors for ACL graft failure. Study Design Case-control study; Level of evidence, 3. Methods Twenty-one patients with ACL graft failure were identified over a 2-year period. Forty-two age- and sex-matched controls were identified over the same period. A 1:2 matched case-control design was used to evaluate activity level after reconstruction and graft type as risk factors for ACL graft failure. Logistic regression analysis was used to determine odds ratios for activity level after reconstruction and for graft type among cases and controls. Association (interaction) between activity level after reconstruction and graft type was evaluated comparing stratum-specific odds ratios. Results Univariate logistic regression models showed an increased odds of ACL graft failure for those with high activity level compared with low activity level (odds ratio [OR], 5.53; 95% confidence interval [CI], 1.18–28.61; P = .03) and for allografts compared with autografts (OR, 5.56; 95% CI 1.55–19.98; P = .009). A bivariate logistic regression model showed a 35% change in the odds ratio for activity level (OR, 4.33; 95% CI, 0.89–21.16; P = .07) and a 13% change in the odds ratio for allograft compared with autograft (OR, 4.93; 95% CI, 1.34–18.20; P = .02). Stratum-specific odds ratios between activity level and graft type show a multiplicative interaction between higher activity level and allograft for much greater odds of ACL graft failure. Conclusion Higher activity level after reconstruction and allograft use for reconstruction are risk factors for ACL graft failure. Stratum-specific odds ratios show a multiplicative interaction between higher activity level after ACL reconstruction and allograft use, greatly increasing the odds for ACL graft failure.

The Influence of Hamstring Autograft Size on Patient- Reported Outcomes and Risk of Revision After Anterior Cruciate Ligament Reconstruction: A Multicenter Orthopaedic Outcomes Network (MOON) Cohort Study

PURPOSE The purpose of this study was to evaluate the effect of graft size on patient-reported outcomes and revision risk after anterior cruciate ligament (ACL) reconstruction. METHODS A retrospective chart review of prospectively collected cohort data was performed, and 263 of 320 consecutive patients (82.2%) undergoing primary ACL reconstruction with hamstring autograft were evaluated. We recorded graft size; femoral tunnel drilling technique; patient age, sex, and body mass index at the time of ACL reconstruction; Knee Injury and Osteoarthritis Outcome Score (KOOS) and International Knee Documentation Committee score preoperatively and at 2 years postoperatively; and whether each patient underwent revision ACL reconstruction during the 2-year follow-up period. Revision was used as a marker for graft failure. The relation between graft size and patient-reported outcomes was determined by multiple linear regression. The relation between graft size and risk of revision was determined by dichotomizing graft size at 8 mm and stratifying by age. RESULTS After we controlled for age, sex, operative side, surgeon, body mass index, graft choice, and femoral tunnel drilling technique, a 1-mm increase in graft size was noted to correlate with a 3.3-point increase in the KOOS pain subscale (P = .003), a 2.0-point increase in the KOOS activities of daily living subscale (P = .034), a 5.2-point increase in the KOOS sport/recreation function subscale (P = .004), and a 3.4-point increase in the subjective International Knee Documentation Committee score (P = .026). Revision was required in 0 of 64 patients (0.0%) with grafts greater than 8 mm in diameter and 14 of 199 patients (7.0%) with grafts 8 mm in diameter or smaller (P = .037). Among patients aged 18 years or younger, revision was required in 0 of 14 patients (0.0%) with grafts greater than 8 mm in diameter and 13 of 71 patients (18.3%) with grafts 8 mm in diameter or smaller. CONCLUSIONS Smaller hamstring autograft size is a predictor of poorer KOOS sport/recreation function 2 years after primary ACL reconstruction. A larger sample size is required to confirm the relation between graft size and risk of revision ACL reconstruction. LEVEL OF EVIDENCE Level III, retrospective comparative study.

The Prognosis and Predictors of Sports Function and Activity at Minimum 6 Years After Anterior Cruciate Ligament Reconstruction

Background: The predictors of anterior cruciate ligament reconstruction (ACLR) outcome at 6 years as measured by validated patient-based outcome instruments are unknown. Hypothesis: Certain variables evaluated at the time of ACLR will predict return to sports function (as measured by the International Knee Documentation Committee [IKDC] questionnaire and the Knee injury and Osteoarthritis Outcome Score [KOOS] Sports and Recreation subscale), knee-related quality of life (KOOS Knee Related Quality of Life subscale), and activity level (Marx Activity Scale). Potential predictor variables include demographic factors, surgical technique and graft choice for ACLR, and intra-articular injuries and treatment. Study Design: Cohort study; Level of evidence, 2. Methods: All patients with unilateral ACLRs from 2002 currently enrolled in the MOON (Multicenter Orthopaedic Outcomes Network) cohort were evaluated. Patients completed the validated outcome instruments preoperatively. Physicians documented intra-articular pathologic abnormalities, treatment, and surgical techniques used at the time of surgery. At 2 and 6 years postoperatively, patients completed the same validated outcome instruments. Results: Follow-up was obtained at 2 years (88%) and at 6 years (84%). The cohort was 57% male with a median age of 23 years at enrollment. The ability to perform sports function was maintained at 6 years, but the Marx activity level continued to decline from baseline. Revision ACLR and use of allograft predicted worse outcomes on the IKDC and both KOOS subscales. Lateral meniscus treatment, smoking status, and body mass index at baseline were each predictors on 2 of 3 scales. The predictors of lower activity level were revision ACLR and female sex. Conclusion: Six years after ACLR, patients could perform sports-related functions and maintain a high knee-related quality of life similar to their 2-year level, although their physical activity level (Marx) dropped over time. Choosing autograft rather than allograft, not smoking, and having normal body mass index are advised to improve long-term outcomes.

Risk Factors and Predictors of Subsequent ACL Injury in Either Knee After ACL Reconstruction: Prospective Analysis of 2488 Primary ACL Reconstructions From the MOON Cohort.

Background: Anterior cruciate ligament (ACL) reinjury results in worse outcomes and increases the risk of posttraumatic osteoarthritis. Purpose: To identify the risk factors for both ipsilateral and contralateral ACL tears after primary ACL reconstruction (ACLR). Study Design: Cohort study; Level of evidence, 3. Methods: Data from the Multicenter Orthopaedic Outcomes Network (MOON), a prospective longitudinal cohort, were used to identify risk factors for ACL retear. Subjects with primary ACLR, no history of contralateral knee surgery, and a minimum of 2-year follow-up data were included. Age, sex, Marx activity score, graft type, lateral meniscal tear, medial meniscal tear, sport played at index injury, and surgical facility were evaluated to determine their contribution to both ipsilateral retear and contralateral ACL tear. Results: A total of 2683 subjects with average age of 27 ± 11 years (1498 men; 56%) met all study inclusion/exclusion criteria. Overall there were 4.4% ipsilateral graft tears and 3.5% contralateral ACL tears. The odds of ipsilateral ACL retear were 5.2 times greater for an allograft (P < .01) compared with a bone–patellar tendon–bone (BTB) autograft; the odds of retear were not significantly different between BTB autograft and hamstring autograft (P = .12). The odds of an ipsilateral ACL retear decreased by 0.09 for every yearly increase in age (P < .01) and increased by 0.11 for every increased point on the Marx score (P < .01). These odds were not significantly influenced by sex, smoking status, sport played, medial or lateral meniscal tear, or consortium site (P > .05). The odds of a contralateral ACL tear decreased by 0.04 for every yearly increase in age (P = .04) and increased by 0.12 for every increased point on the Marx score (P < .01); these odds were not significantly different between sex, smoking status, sport played, graft type, medial meniscal tear, or lateral meniscal tear (P > .05). Conclusion: Younger age, higher activity level, and allograft graft type were predictors of increased odds of ipsilateral graft failure. Higher activity and younger age were found to be risk factors in contralateral ACL tears.

Are Articular Cartilage Lesions and Meniscus Tears Predictive of IKDC, KOOS, and Marx Activity Level Outcomes After Anterior Cruciate Ligament Reconstruction? A 6-Year Multicenter Cohort Study

Background: Identifying risk factors for inferior outcomes after anterior cruciate ligament reconstruction (ACLR) is important for prognosis and future treatment. Hypothesis: Articular cartilage lesions and meniscus tears/treatment would predict International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score (KOOS) (all 5 subscales), and Marx activity level at 6 years after ACLR. Study Design: Cohort study (prognosis); Level of evidence, 1. Methods: Between 2002 and 2004, a total of 1512 ACLR patients were prospectively enrolled and followed longitudinally, with the IKDC, KOOS, and Marx activity score completed at entry, 2 years, and 6 years. A logistic regression model was built incorporating variables from patient demographics, surgical technique, articular cartilage injuries, and meniscus tears/treatment to determine the predictors (risk factors) of IKDC and KOOS scores and Marx activity level at 6 years. Results: A minimum follow-up on 86% (1307/1512) of the cohort was completed at 6 years. The cohort was 56% male and had a median age of 23 years at the time of enrollment, with 76% reporting a noncontact injury mechanism. Incidence of concomitant injury at the time of surgery consisted of the following: articular cartilage (medial femoral condyle [MFC], 25%; lateral femoral condyle [LFC] 20%; medial tibial plateau [MTP], 6%; lateral tibial plateau [LTP], 12%; patella, 20%; trochlear, 9%) and meniscus (medial, 38%; lateral, 46%). Both articular cartilage lesions and meniscus tears were significant predictors of 6-year outcomes on the IKDC and KOOS. Grade 3 or 4 articular cartilage lesions (excluding patella) significantly reduced IKDC and KOOS scores at 6 years. The IKDC demonstrated worse outcomes with the presence of a grade 3 or 4 chondral lesion on the MFC, MTP, and LFC. Likewise, the KOOS score was negatively affected by cartilage injury. The sole significant predictor of reduced Marx activity level was the presence of a grade 4 lesion on the MFC. Lateral meniscus repairs did not correlate with inferior results, but medial meniscus repairs predicted worse IKDC and KOOS scores. Lateral meniscus tears left alone significantly improved prognosis. Small partial meniscectomies (<33%) on the medial meniscus fared worse; conversely, larger excisions (>50%) on either the medial or lateral menisci improved prognosis. Analogous to previous studies, other significant predictors of lower outcome scores were lower baseline scores, higher body mass index, lower education level, smoking, and anterior cruciate ligament revisions. Conclusion: Both articular cartilage injury and meniscus tears/treatment at the time of ACLR were significant predictors of IKDC and KOOS scores 6 years after ACLR. Similarly, having a grade 4 MFC lesion significantly reduced a patient’s Marx activity level score at 6 years.

Intra-articular Findings in Primary and Revision Anterior Cruciate Ligament Reconstruction Surgery A Comparison of the MOON and MARS Study Groups

Background: At the time of anterior cruciate ligament (ACL) reconstruction, there are usually concurrent meniscal and articular cartilage injuries. It is unclear if there is a significant difference between intra-articular injuries at the time of a primary ACL reconstruction compared with revision ACL reconstruction. Purpose: To compare the meniscal and articular cartilage injuries found at the time of primary and revision ACL reconstruction surgery and to determine associations between primary and revision surgery and specific intra-articular findings. Study Design: Cohort study (prevalence); Level of evidence, 2. Methods: Primary and revision ACL surgeries were identified from the Multicenter Orthopedic Outcomes Network (MOON) and Multicenter ACL Revision Study (MARS) study groups, respectively, from January 1, 2007 to November 1, 2008. Demographic data on individual patients were analyzed including age, body mass index (BMI), and gender. Intra-articular findings including the presence of medial or lateral meniscal tears and chondral damage to articular surfaces were analyzed for each patient. Comparisons of intra-articular findings at the time of surgery for the 2 groups were analyzed. Chondral damage in the medial and lateral compartments was analyzed considering previous meniscal tear as a possible confounder. Results: There were 508 patients undergoing primary ACL reconstruction and 281 patients undergoing revision ACL reconstruction who were identified for inclusion. There were no differences in the mean age, BMI, and gender in the 2 study groups. There was a decreased odds ratio (OR) of new untreated lateral meniscal tears (OR, 0.54; P < .01) but not of medial meniscal tears (OR, 0.86; P = .39) in revision compared with primary ACL reconstruction. There was an increased OR of Outerbridge grade 3 and 4 articular cartilage injury in revision compared with primary ACL reconstruction in the lateral compartment (OR, 1.73; P = .04) and in the patellar-trochlear compartment (OR, 1.70; P = .04) but not in the medial compartment (OR, 1.33; P = .23). There was an increased OR of Outerbridge grade 3 and 4 articular cartilage injury in patients from both groups having a prior medial meniscectomy on the medial femoral condyle (OR, 1.44; P < .01) and on the medial tibial plateau (OR, 1.63; P < .01). There was an increased OR of Outerbridge grade 3 and 4 articular cartilage injury in patients from both groups having a prior lateral meniscectomy on the lateral femoral condyle (OR, 1.65; P < .01) and on the lateral tibial plateau (OR, 1.56; P < .01). Conclusion: Meniscal tears are a common finding in both primary and revision ACL reconstruction. These results show a decreased OR of new untreated lateral meniscal tears in revision compared with primary ACL reconstruction. A previous medial or lateral meniscectomy increases the OR of articular cartilage damage in the medial or lateral compartments, respectively. Even when controlling for meniscus status, there is an increased OR in revision compared with primary ACL reconstruction of significant lateral compartment and patellar-trochlear chondral damage but not medial compartment chondral damage.

Bupivacaine use after knee arthroscopy: Pharmacokinetics and pain control study

Bupivacaine (Marcaine) pharmacokinetics were determined in 11 patients receiving the drug intraarticularly after arthroscopic procedures performed on the knee with patients under general anesthesia. Forty milliliters of 0.25% bupivacaine (100 mg) were given as a bolus into the intraarticular space of the knee of each patient. The thigh tourniquet was released 2-3 min after injection and blood samples were obtained 5, 10, 15, 20, 30, 60, 120, 180, 250, and 300 min after tourniquet release. Pharmacokinetic parameters obtained were (mean +/- SD): Vd beta 206 +/- 88 L; Cle 0.816 +/- 0.378 L/min; t 1/2 beta 189 +/- 84 min; ka 9.92 +/- 6.79 x 10/min; Cpmax 0.48 +/- 0.20 micrograms/ml; and tmax 43.4 +/- 23.1 min. Correlations between higher peak plasma concentrations and longer tourniquet times (p = 0.02) and shorter intervals from injection to tourniquet deflation (p = 0.03) were found using multiple linear regression. Our results indicate that injections of 100 mg of bupivacaine intraarticularly after knee arthroscopy will produce peak blood levels within the 1st h after surgery and that these levels will be well below those noted to produce toxic reactions. Peak levels can be minimized with shorter tourniquet inflation times and with longer injection to tourniquet release intervals. Ninety healthy adult outpatient knee arthroscopy patients also were studied to evaluate the effectiveness of bupivacaine in relieving postoperative knee discomfort when injected immediately postoperatively. The subjects were randomized into four groups: (a) intraarticular injection of saline, (b) intraarticular injection of bupivacaine, (c) subcutaneous injection of bupivacaine at the portal sites, and (d) both intraarticular and subcutaneous injection of bupivacaine.(ABSTRACT TRUNCATED AT 250 WORDS)