Patient and Operative Risk Factors for Osteoarthritis After Primary Anterior Cruciate Ligament Reconstruction: A Cohort Study of 41,976 Patients.

BACKGROUND: The reported incidence of posttraumatic knee osteoarthritis (PTOA) after primary anterior cruciate ligament reconstruction (ACLR) varies considerably. Further, there are gaps in identifying which patients are at risk for PTOA after ACLR and whether there are modifiable factors. PURPOSE: To (1) determine the incidence of PTOA in a primary ACLR cohort and (2) identify patient and perioperative factors associated with the development of PTOA after primary ACLR. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Data from the Kaiser Permanente ACLR Registry were used to conduct a cohort study. Patients who had undergone primary ACLR without a previous diagnosis of osteoarthritis were identified (2009-2020). The crude incidence of PTOA was calculated using the Aalen-Johansen estimator with a multistate model. The association of patient and operative factors with the development of PTOA after primary ACLR was modeled as a time to event using multistate Cox proportional hazards regression. Models stratified by age (<22 and ≥22 years) were also conducted because of the effect modification of age. RESULTS: The study sample included 41,976 cases of primary ACLR. The incidence of PTOA was 1.7%, 5.1%, and 13.6% at 2, 5, and 10 year follow-ups, respectively. Risk factors for PTOA that were consistently identified in the overall cohort and age-stratified groups included a body mass index ≥30 versus <30 and an allograft or quadriceps tendon autograft versus a hamstring tendon autograft. Patients presenting with knee pain after ACLR were further identified when considering postoperative factors. Other risk factors for PTOA in the overall cohort included age ≥22 versus <22 years, bone-patellar tendon-bone autograft versus hamstring tendon autograft, hypertension, cartilage injury, meniscal injury, revision after primary ACLR with concomitant meniscal/cartilage surgery, multiligament injury, other activity at the time of injury compared with sport, and tibial tunnel drilling technique rather than the anteromedial portal. CONCLUSION: Knee pain after ACLR may be an early sign of PTOA. Surgeons should consider the adverse associations of a higher body mass index and an allograft or quadriceps tendon autograft with the development of PTOA, as these were factors identified with a higher risk, regardless of a patient's age at the time of primary ACLR.

An Interrupted Time Series Analysis Measuring the Impact of Research and Education on Clinical Practice: Decreasing Allograft Use in Young Patients Using a Registry to Track Outcomes.

BACKGROUND: We sought to evaluate whether allograft utilization for primary anterior cruciate ligament reconstruction (ACLR) within our health-care system changed following the implementation of an allograft reduction intervention and whether revision rates within the health-care system changed following the initiation of the intervention. METHODS: We conducted an interrupted time series study using data from Kaiser Permanente's ACL Reconstruction Registry. In our study, we identified 11,808 patients who were ≤21 years of age and underwent primary ACLR from January 1, 2007, through December 31, 2017. The pre-intervention period (15 quarters) was January 1, 2007, through September 30, 2010, and the post-intervention period (29 quarters) was October 1, 2010, through December 31, 2017. Poisson regression was used to evaluate trends over time in 2-year revision rates according to the quarter in which the primary ACLR was performed. RESULTS: Allograft utilization increased pre-intervention from 21.0% in 2007 Q1 to 24.8% in 2010 Q3. Utilization decreased post-intervention from 29.7% in 2010 Q4 to 2.4% in 2017 Q4. The quarterly 2-year revision rate increased from 3.0 to 7.4 revisions per 100 ACLRs pre-intervention and decreased to 4.1 revisions per 100 ACLRs by the end of the post-intervention period. Poisson regression found an increasing 2-year revision rate over time pre-intervention (rate ratio [RR], 1.03 [95% confidence interval (CI), 1.00 to 1.06] per quarter) and a decreasing rate over time post-intervention (RR, 0.96 [95% CI, 0.92 to 0.99]). CONCLUSIONS: In our health-care system, we saw a decrease in allograft utilization following the implementation of an allograft reduction program. During the same period, a decrease in the ACLR revision rate was observed. LEVEL OF EVIDENCE: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Optimizing anterior cruciate ligament reconstruction: Individualizing the decision-making process using data from the Kaiser Permanente ACLR Registry: 2018 OREF award paper.

Despite years of study, controversy remains regarding the optimal graft for anterior cruciate ligament reconstruction (ACLR), suggesting that a single graft type is not ideal for all patients. A large community based ACLR Registry that collects prospective data is a powerful tool that captures information and can be analyzed to optimize surgery for individual patients. The studies highlighted in this paper were designed to optimize and individualize ACLR surgery and have led to changes in surgeon behavior and improvements in patient outcomes. Kaiser Permanente (KP) is an integrated health care system with 10.6 million members and more than 50 hospitals. Every KP member who undergoes an ACLR is entered into the Registry, and prospectively monitored. The Registry uses a variety of feedback mechanisms to disseminate Registry findings to the ACLRR surgeons and appropriately influence clinical practices and enhance quality of care. Allografts were found to have a 3.0 times higher risk of revision than bone-patellar tendon-bone (BPTB) autografts. Allograft irradiation >1.8 Mrad, chemical graft processing, younger patients, BPTB allograft, and male patients were all associated with a higher risk of revision surgery. By providing feedback to surgeons, overall allograft use has decreased by 27% and allograft use in high-risk patients ≤21 years of age decreased 68%. We have identified factors that influence the outcomes of ACLR. Statement of Clinical Significance: We found that information derived from an ACLR Registry and shared with the participating surgeons directly decreased the use of specific procedures and implants associated with poor outcomes.

The Association Between Tibial Slope and Revision Anterior Cruciate Ligament Reconstruction in Patients ≤21 Years Old: A Matched Case-Control Study Including 317 Revisions.

BACKGROUND: There is evidence that tibial slope may play a role in revision risk after anterior cruciate ligament reconstruction (ACLR); however, prior studies are inconsistent. PURPOSE: To determine (1) whether there is a difference in lateral tibial posterior slope (LTPS) or medial tibial posterior slope (MTPS) between patients undergoing revised ACLR and those not requiring revision and (2) whether the medial-to-lateral slope difference is different between these 2 groups. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: We conducted a matched case-control study (2006-2015). Cases were patients aged ≤21 years who underwent revision surgery after primary unilateral ACLR; controls were patients aged ≤21 years without revision who were identified from the same source population. Controls were matched to cases by age, sex, body mass index, race, graft type, femoral fixation device, and post-ACLR follow-up time. Tibial slope measurements were made by a single blinded reviewer using magnetic resonance imaging. The Wilcoxon signed rank test and McNemar test were used for continuous and categorical variables, respectively. RESULTS: No difference was observed between revised and nonrevised ACLR groups for LTPS (median: 6° vs 6°, P = .973) or MTPS (median: 4° vs 5°, P = .281). Furthermore, no difference was found for medial-to-lateral slope difference (median: -1 vs -1, P = .289). A greater proportion of patients with revised ACLR had an LTPS ≥12° (7.6% vs 3.8%) and ≥13° (4.7% vs 1.3%); however, this was not statistically significant after accounting for multiple testing. CONCLUSION: We failed to observe an association between revision ACLR surgery and LTPS, MTPS, or medial-to-lateral slope difference. However, there was a greater proportion of patients in the revision ACLR group with an LTPS ≥12°, suggesting that a minority of patients who have more extreme values of LTPS have a higher revision risk after primary ACLR. A future cohort study evaluating the angle that best differentiates patients at highest risk for revision is needed.

Femoral-tibial fixation affects risk of revision and reoperation after anterior cruciate ligament reconstruction using hamstring autograft.

PURPOSE: Newer fixation devices for hamstring (HS) autograft have been introduced over the years, yet the impact of these devices on ACLR outcomes requiring surgical intervention remains unclear. We sought to evaluate the risk of aseptic revision and reoperation after HS autograft ACLR according to various femoral-tibial fixation methods. METHODS: A cohort study was conducted using the Kaiser Permanente ACLR Registry. Primary isolated unilateral ACLR patients who received a HS autograft were identified (2007-2014). Fixation devices were categorized as crosspin, interference, suspensory, or combination (defined as more than one fixation device used on the same side) and femoral-tibial fixation groups used in more than 500 ACLR were evaluated. Cox proportional-hazard regression was used to evaluate the association between femoral-tibial fixation method and outcomes while adjusting for confounders. RESULTS: 6,593 primary ACLR were included. Four femoral-tibial fixation groups had more than 500 ACLR: suspensory-interference (n = 3004, 45.6%), interference-interference (n = 1659, 25.2%), suspensory-combination (n = 1103, 16.7%), and crosspin-interference (n = 827, 12.5%). After adjusting for covariates, revision risk was lower for crosspin-interference (HR = 0.43, 95% CI 0.29-0.65) and interference-interference (HR = 0.63, 95% CI 0.41-0.95) methods compared to the suspensory-interference. In contrast, reoperation risk was higher for crosspin-interference (HR = 2.13, 95% CI 1.37-3.32) and suspensory-combination (HR = 1.68, 95% CI 1.04-2.69) methods compared to suspensory-interference. CONCLUSIONS: ACLR using HS autograft appears to have the lowest risk of aseptic revision when crosspin or interference fixation is used on the femoral side and is coupled with an interference screw on the tibial side. LEVEL OF EVIDENCE: III.

Analysis of 2019 Patients Undergoing Revision Anterior Cruciate Ligament Reconstruction From a Community-Based Registry.

BACKGROUND: Knowledge of patient characteristics, surgical fixation, graft choice, outcomes, and concurrent injuries of revision anterior cruciate ligament reconstruction (ACLR) is limited. PURPOSE: To describe the current cohort of revision ACLR captured by a community registry and the outcomes observed in the registered patients. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Patients who underwent revision ACLR registered between February 2005 and June 2014, by 200 surgeons in 46 hospitals, were evaluated. The Kaiser Permanente ACLR Registry (KPACLRR) collected data intraoperatively and postoperatively using paper forms, electronic medical records, administrative claims data, and patient-reported outcomes. The KPACLRR cohort was longitudinally followed, and outcomes were prospectively ascertained. Outcomes (ie, revisions, subsequent operative procedures, deep surgical site infections, and deep venous thrombosis) were adjudicated via a chart review. Descriptive statistics were employed. RESULTS: Of 2019 patients who underwent revision ACLR, at a median follow-up of 2.2 years (interquartile range, 1.0-3.8 years), 212 (10.5%) required subsequent operative procedures, and 86 (4.3%) were revised a second time. At the time of revision, 55.1% of the patients had at least 1 concurrent meniscal injury, and 26% of those were repairable. Cartilage injuries were present in 42.0% of patients. Deep surgical site infections occurred in 12 patients (0.6%), deep venous thrombosis occurred in 5 patients (0.3%), and 1 patient (0.1%) had a pulmonary embolism. CONCLUSION: Revision ACLR can be performed with a low short-term revision rate and relatively few complications. At the time of revision, nearly half of these patients had an irreparable meniscal injury, and slightly less than half had a cartilage injury. A large community-based ACLR registry is useful in informing surgeons of current treatment practices, prevalence of concurrent injuries, and outcomes associated with the procedures, especially infrequent procedures such as revision ACLR.

Increased Risk of Revision After Anterior Cruciate Ligament Reconstruction With Bone-Patellar Tendon-Bone Allografts Compared With Autografts.

BACKGROUND: The use of allograft tissue for anterior cruciate ligament reconstruction (ACLR) remains controversial. PURPOSE: To compare the risk of aseptic revision between bone-patellar tendon-bone (BPTB) autografts and BPTB allografts. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A retrospective cohort study of prospectively collected data was conducted using the Kaiser Permanente ACLR Registry. A cohort of patients who underwent primary unilateral ACLR with BPTB autografts and BPTB allografts was identified. Aseptic revision was the endpoint. The type of graft and allograft processing method (nonprocessed, <1.8-Mrad, and ≥1.8-Mrad irradiation) were the exposures of interest evaluated. Age (≤21 and ≥22 years) was evaluated as an effect modifier. Analyses were adjusted for age, sex, and race. Kaplan-Meier curves and Cox proportional hazards models were employed. Hazard ratios (HRs) and 95% CIs are provided. RESULTS: The BPTB cohort consisted of 5586 patients: 3783 (67.7%) were male, 2359 (42.2%) were white, 1029 (18.4%) had allografts (nonprocessed: 155; <1.8 Mrad: 525; ≥1.8 Mrad: 288), and 4557 (81.6%) had autografts. The median age was 34.9 years (interquartile range [IQR], 25.4-44.0) for allograft cases and 22.0 years (IQR, 17.6-30.0) for autograft cases. The estimated cumulative revision rate at 2 years was 4.1% (95% CI, 2.9%-5.9%) for allografts and 1.7% (95% CI, 1.3%-2.2%) for autografts. BPTB allografts had a significantly higher adjusted risk of revision than BPTB autografts (HR, 4.54; 95% CI, 3.03-6.79; P < .001). This higher risk of revision was consistent with all allograft processing methods when compared with autografts and was also consistently higher in patients with allografts regardless of age. CONCLUSION: When BPTB allograft tissue was used for ACLR, an overall 4.54 times adjusted higher risk of revision was observed compared with surgery performed with a BPTB autograft. Whether the tissue was irradiated with either high- or low-dose radiation, chemically processed, or not processed at all made little difference in the risk of revision. The differences in the revision risk were also consistent in younger and older patients. Surgeons and patients should be aware of the increased risk of revision when a BPTB allograft is used for ACLR.

Increased Risk of Revision After Anterior Cruciate Ligament Reconstruction With Soft Tissue Allografts Compared With Autografts: Graft Processing and Time Make a Difference.

BACKGROUND: The optimal graft for anterior cruciate ligament reconstruction (ACLR) remains controversial. PURPOSE: To compare the risk of aseptic revision between bone-patellar tendon-bone (BPTB) autografts, hamstring autografts, and soft tissue allografts. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Prospectively collected ACLR cases reconstructed with BPTB autografts, hamstring autografts, and soft tissue allografts were identified using the Kaiser Permanente ACLR Registry. Aseptic revision was the endpoint. The type of graft and allograft processing method (nonprocessed, <1.8-Mrad irradiation with and without chemical processing [Allowash or AlloTrue], ≥1.8-Mrad irradiation with and without chemical processing, and chemical processing alone [BioCleanse]) were the exposures evaluated. Analyses were adjusted for age, sex, and race. Kaplan-Meier curves and Cox proportional hazards models were employed. RESULTS: The cohort included 14,015 cases: there were 8924 (63.7%) male patients, there were 6397 (45.6%) white patients, 4557 (32.5%) ACLRs used BPTB autografts, 3751 ACLRs (26.8%) used soft tissue allografts, and 5707 (40.7%) ACLRs used hamstring autografts. The median age was 34.6 years for soft tissue allografts, 24.3 years for hamstring autografts, and 22.0 years for BPTB autografts. The crude nonadjusted revision rates were 85 (1.9%) in BPTB autograft cases, 132 (2.3%) in hamstring autograft cases, and 83 (2.2%) in soft tissue allograft cases. After adjusting for age, sex, and race, compared with hamstring autografts, a higher risk of revision was found with allografts with ≥1.8 Mrad without chemical processing after 2.5 years (hazard ratio [HR], 3.88; 95% CI, 1.48-10.12) and ≥1.8 Mrad with chemical processing after 1 year (HR, 3.43; 95% CI, 1.58-7.47) and with BioCleanse processed grafts at any time point (HR, 3.02; 95% CI, 1.40-6.50). Nonprocessed allografts and those irradiated with <1.8 Mrad with or without chemical processing were not found to have a different risk of revision compared with hamstring autografts. Compared with BPTB autografts, a higher risk of revision was seen with hamstring autografts (HR, 1.51; 95% CI, 1.15-1.99) and BioCleanse processed allografts (HR, 4.67; 95% CI, 2.15-10.16). Allografts irradiated with <1.8 Mrad with chemical processing (Allowash or AlloTrue) (HR, 2.19; 95% CI, 1.42-3.38) and without chemical processing (HR, 2.31; 95% CI, 1.40-3.82) had a higher risk of revision, as did allografts with ≥1.8 Mrad without chemical processing after 2 years (HR, 6.30; 95% CI, 3.18-12.48) and ≥1.8 Mrad with chemical processing (Allowash or AlloTrue) after 1 year (HR, 5.03; 95% CI, 2.30-11.00) compared with BPTB autografts. Nonprocessed allografts did not have a higher risk of revision compared with autografts. With the numbers available, direct comparisons between the specific allograft processing methods were not possible. CONCLUSION: When soft tissue allografts are used for ACLR, processing and time from surgery affect the risk of revision. Tissue processing has a significant effect on the risk of revision surgery, which is most profound with more highly processed grafts and increases with increasing follow-up time. Surgeons and patients need to be aware of the increased risks of revision with the various soft tissue allografts used for ACLR.

Surgical Technique Trends in Primary ACL Reconstruction from 2007 to 2014.

BACKGROUND: The surgical technique for anterior cruciate ligament (ACL) reconstruction has evolved as a result of improved understanding of ligament biomechanics, anatomy, device development, and failed reconstructions. Studies on surgical technique preferences have been limited to surgeon surveys, which are subject to selection and recall bias. The purpose of this study was to evaluate ACL reconstruction surgical technique and yearly revision rate trends in a community-based setting. METHODS: A population-based epidemiological study was conducted using data on primary ACL reconstruction procedures registered in an ACL reconstruction registry from 2007 to 2014. Changes in the incidence rates of different types of femoral tunnel drilling methods, different types of grafts and graft fixation, and revisions were studied. Adjusted incidence rate ratios (IRRs) are provided. RESULTS: Of the 21,686 ACL reconstructions studied, 72.4% were performed by sports medicine fellowship-trained surgeons. The incidence rate of femoral tunnel drilling via a tibial tunnel decreased at an adjusted rate of 26% per year (IRR = 0.74, 95% confidence interval [CI] = 0.71 to 0.78), from 56.4% to 17.6% during the study period. The incidence rate of medial portal drilling increased from 41.3% to 65.1% at an adjusted rate of 11% per year (IRR = 1.11, 95% CI = 1.09 to 1.13), and the incidence rate of drilling through a lateral approach increased from 2.3% to 17.3% at an adjusted rate of 53% per year (IRR = 1.53, 95% CI = 1.39 to 1.67). There was no change in the use of hamstring autograft, bone-patellar tendon-bone autograft, or tibial tendon allograft. Use of first-generation bioabsorbable femoral and tibial fixation decreased for all graft types. For soft-tissue grafts, usage of suspensory metal femoral fixation increased 12% to 13% per year (IRR = 1.12, 95% CI = 1.09 to 1.15 for tibial tendon grafts; IRR = 1.13, 95% CI = 1.10 to 1.15 for hamstring grafts). For bone-patellar tendon-bone autografts, the use of femoral fixation with interference biocomposite screws increased 7% per year (IRR = 1.07, 95% CI = 1.04 to 1.10). On the tibial side, utilization of biocomposite screws increased for all graft types. No association was found between revision rate and the year of the primary operation. CONCLUSIONS: Surgeons changed their femoral tunnel drilling technique over the study period, whereas the incidence rates of specific graft utilization remained stable. There has been a shift away from first-generation bioabsorbable fixation and increasing use of biocomposite fixation across all graft types. Early cumulative revision rates remained stable.

Type and frequency of healthcare encounters can predict poor surgical outcomes in anterior cruciate ligament reconstruction patients.

BACKGROUND: Several challenges are associated with collecting clinically meaningful post-operative outcomes. The widespread implementation of electronic medical records (EMR) offers a new opportunity to evaluate surgical outcomes using routinely collected data in these systems. This study evaluated whether surgical outcomes can be ascertained from EMR's hospital and outpatient encounters. Specifically, we evaluated anterior cruciate ligament reconstructions (ACLR) outcomes. METHODS: A retrospective cohort study of 6985 ACLRs performed between 2/2005-9/2012 was conducted. Patient encounters during days 1-90 and days 91-180 after ACLR surgery were the exposures of interest. Nine hospital and eight outpatient encounter types were evaluated. The main endpoint of the study was revision surgery six months after ACLR. RESULTS: The cohort was 66.7% male, the mean age was 28 (standard deviation=11) years-old, and the incidence of revision was 1.5% (n=105). After adjustments, in days 1-90 post-ACLR, compared to patients with 0-4 orthopedic office visits, patients with 5-9 (hazard ratio (HR)=9.9, 95% confidence interval(CI), 4.3-23.2) and those with 10 or more (HR=13.8, 95%CI, 5.6-33.8) visits had a higher risk of revision. In days 91-180, patients with any outpatient hospital encounters (HR=2.5, 95%CI 1.4-4.5) had a higher risk of revision than patients without visits. Additionally, patients with 4-5 regular office visits (HR=3.8 times, 95%CI, 2.0-7.0) had a higher risk of revision surgery than those with 0-1 visits. DISCUSSION: The number of post-operative outpatient visits was associated with ACLR revision surgery. Using EMR encounters to assess surgical outcomes is a viable option for monitoring ACLR patients. The simple assessment of visit types and number of encounters alone can provide valuable information regarding the normal course of rehabilitation of a surgical patient and possible deviation from this normal course. In large cohorts of patients, this type of patient surveillance can assist surgeons with monitoring their patients.

A comparison of revision and rerupture rates of ACL reconstruction between autografts and allografts in the skeletally immature.

PURPOSE: Anterior cruciate ligament reconstructions (ACLRs) in skeletally immature patients are increasing. The purpose of this study is to describe the demographics, graft usage, revision, and re-operation rates in skeletally immature ACLRs in the Kaiser Permanente healthcare system. METHODS: Skeletally immature patients (<17.0 years old with open physes) were identified using the Kaiser Permanente ACLR registry. Multi-ligament reconstructions and physeal-sparing ACLRs were excluded. Aseptic revision and same-knee re-operation were the outcomes of interest. Exposure of interest was graft type; bone-patellar-tendon-bone (BPTB) autograft, hamstring autograft, and any type of allograft. Age, gender, body mass index (BMI), and race were evaluated as confounders. Cox proportional hazard models stratified by surgeon were used to analyse the risk of revision and re-operation. RESULTS: A total of 534 primary ACLR cases were evaluated with a mean follow-up of 2.9 years. The majority were hamstring autografts (n = 388, 72.7%), male (n = 339, 63.9%), and White (n = 232, 43.4%). Median age was 14.9 years, and median BMI was 21.9 kg/m(2). There were 44 (8.2%) aseptic revisions and 48 (9.0%) same-knee re-operations. The incidence rate for revision was BPTB autograft 5.5%, hamstring autograft 7.5%, and allograft 13.2%. After adjusting for confounders and surgeon clustering effect, the risk of aseptic revision and revision between allograft and hamstring autograft did not reach statistical significance. CONCLUSION: Graft selection differs in skeletally immature patients with a preponderance of surgeries being performed with hamstring tendon autografts. High revision rates were identified for all graft types used, though differences in revision rates across different graft types did not reach statistical significance. Surgeons should be aware of high rates of revision in this skeletally immature young population, although type of graft used did not appear to make a difference. LEVEL OF EVIDENCE: III.

Age-Related Risk Factors for Revision Anterior Cruciate Ligament Reconstruction: A Cohort Study of 21,304 Patients From the Kaiser Permanente Anterior Cruciate Ligament Registry.

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/m(2) (HR, 0.75; 95% CI, 0.59-0.95) and BMI >35 kg/m(2) (HR, 0.49; 95% CI, 0.34-0.70) compared with those with a BMI <30 kg/m(2), 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.

Revision Risk After Allograft Anterior Cruciate Ligament Reconstruction: Association With Graft Processing Techniques, Patient Characteristics, and Graft Type.

BACKGROUND: Allograft tissue is a common graft choice for anterior cruciate ligament reconstruction (ACLR). Allograft sterilization methods vary widely across numerous commercial tissue vendors. Multiple studies, despite being limited in sample size, have suggested a higher rate of clinical failure associated with the use of allograft tissue in ACLR when compared with autograft. PURPOSE: To examine the association of graft processing techniques, patient characteristics, and graft type with risk of revision surgery after allograft ACLR. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A retrospective cohort study was conducted that used an integrated United States health care system's ACLR registry to identify primary unilateral cases in which allografts were used. Aseptic revision was the endpoint of the study. Allograft type, processing methods (irradiation dose, AlloWash, AlloTrue, BioCleanse), and graft donor age were assessed as potential risk factors for revision, with adjustment for patient age, sex, and body mass index (BMI) by use of survival analysis. Hazard ratios (HR) and 95% confidence intervals (CIs) were calculated. RESULTS: A total of 5968 primary ACLR cases with allograft were included in the study, of which 3688 (61.8%) were male patients. The median age of the cohort at the time of surgery was 34.1 years (interquartile range, 24.1-42.9 years). The mean time to follow-up (±SD) was 2.1 ± 1.5 years. There were 3751 (62.9%) allograft ACLRs using soft tissue, 1188 (19.9%) with Achilles tendon, and 1029 (17.2%) with bone-patellar tendon-bone (BPTB). Graft processing groups included BioCleanse (n = 367), AlloTrue or AlloWash (n = 2278), irradiation greater than 1.8 Mrad (n = 1146), irradiation up to 1.8 Mrad (n = 3637), and no irradiation (n = 1185). There were 156 (2.6%) aseptic revisions. After adjustment for patient age, sex, and BMI, the use of BioCleanse (HR = 2.45; 95% CI, 1.36-4.40) and irradiation greater than 1.8 Mrad (HR = 1.64; 95% CI, 1.08-2.49) were associated with a higher risk of revision when compared with all other methods of processing. BPTB allografts were at higher risk of revision (HR = 1.79; 95% CI, 1.20-2.66) when compared with soft tissue allografts. Conversely, with every 5-year increase in age, the risk of revision was 0.67 (95% CI, 0.61-0.73) times lower. Male patients were found to be at higher risk of revision when compared with females (HR = 1.47; 95% CI, 1.04-2.07). The use of AlloWash or AlloTrue processing, patient BMI, and graft donor age did not affect revision rate significantly. CONCLUSION: In the largest known study of its kind examining outcome after primary allograft ACLR, graft irradiation greater than 1.8 Mrad, BioCleanse graft processing, younger patient age, male patients, and BPTB allograft were all associated with a higher risk of clinical failure and subsequent revision surgery.

Risk factors associated with revision and contralateral anterior cruciate ligament reconstructions in the Kaiser Permanente ACLR registry.

BACKGROUND: Patients generally choose to undergo anterior cruciate ligament reconstruction (ACLR) to return to their active lifestyles. However, returning to their previous activity level may result in a retear of their reconstructed knee or an injury to their contralateral anterior cruciate ligament (CACL). PURPOSE: To determine the risk factors associated with revision ACLR and contralateral ACLR (CACLR), compare the survival of the reconstructed ACL with the CACL, and determine how the risk factors associated with revision ACLR compare with those for CACLR. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A retrospective cohort study of prospectively collected data from the Kaiser Permanente ACLR registry between February 1, 2005, and September 30, 2012, was conducted. Primary ACLR cases without history of contralateral knee ACL injury were included. The study endpoints included revision ACLR and CACLR. Graft type (bone-patellar tendon-bone [BPTB] autograft, hamstring autograft, and allograft) was the main exposure of interest, and patient characteristics were evaluated as risk factors for revision ACLR and CACLR. Survival analyses were conducted. RESULTS: A total of 17,436 ACLRs were evaluated. The median age was 27.2 years (interquartile range, 18.7-37.7 years), and 64% were males. The 5-year survival for index ACLR was 95.1% (95% CI, 94.5%-95.6%), and for CACL it was 95.8% (95% CI, 95.2%-96.3%). Overall, the cohort had a mean of 2.4 ± 1.7 years of follow-up; 18.2% were lost to follow-up. There were fewer CACLRs per 100 years of observation (0.83) than there were revision ACLRs (1.05) during the study period (P < .001). There was a statistically significant difference in the density of revision ACLR and CACL in BPTB autografts (0.74 vs 1.06, respectively; P = .010), hamstring autografts (1.07 vs 0.81; P = .042), and allografts (1.26 vs 0.67; P < .001). The risk factors for revision ACLR and contralateral surgery were different (P < .05). After adjusting for covariates, factors associated with higher risk of revision ACLR were as follows: allografts, hamstring autografts, male sex, younger age, lower body mass index (BMI), and being white as opposed to black. Factors associated with higher risk of CACLR were as follows: younger age, female sex, and lower BMI. CONCLUSION: The 5-year revision-free and CACLR-free survival rate in this study was 95.1% and 95.8%, respectively. Allografts and hamstring autografts had a higher risk of revision ACLR surgery, and BPTB autografts had a higher risk of CACLR. Males were found to have a higher risk of revision ACLR, and females had a higher risk of CACLR. Increasing age and increasing BMI decreased the risk of both revision and CACLR.

The effect of osteoporosis management on proximal humeral fracture.

HYPOTHESIS AND BACKGROUND: Proximal humeral fractures comprise 10% of fractures in the Medicare population. The effect, if any, of treating osteoporosis to prevent these fractures has not been determined. The primary objective is to determine the effectiveness of a systematic osteoporosis screening and treatment program on the hazard of developing a fracture over the treatment period. The secondary aim is to determine demographic risk factors. METHODS: This is a retrospective cohort study in a health care organization serving 3.3 million members. Individuals selected for dual-energy x-ray absorptiometry screening were (1) women aged 65 years or older; (2) men aged 70 years or older; and (3) individuals aged 50 years or older who have a history of fragility fracture, use glucocorticoids, have a parental history of hip fracture, have rheumatoid arthritis, use alcohol at a high rate, or are cigarette smokers. Treatment consisted primarily of pharmacologic intervention with bisphosphonates. RESULTS: Individuals diagnosed with osteoporosis had a hazard ratio of 7.43 for sustaining a fracture over the study period. Patients screened with dual-energy x-ray absorptiometry had a hazard ratio of 0.17 whereas those treated medically had a hazard ratio of 0.55 versus untreated controls. Risk factors that significantly increased the risk of a fracture developing included age, female gender, white race, diabetes mellitus, and history of a distal radius fracture. DISCUSSION AND CONCLUSION: Over the study period, screening and treatment for osteoporosis significantly decreased the hazard ratio for proximal humeral fracture. This information broadens the impact of such programs because current best practices are primarily based on prevention of spine and hip fractures.

Anterior cruciate ligament injuries in adolescents with open physis: effect of recurrent injury and surgical delay on meniscal and cartilage injuries.

BACKGROUND: Treatment choices for skeletally immature patients sustaining anterior cruciate ligament (ACL) injuries have been controversial. The main dilemma is whether surgical treatment should be provided before patients reach skeletal maturity or whether nonoperative treatment should be provided until the physis has closed. Surgical reconstruction risks physeal damage, while delaying surgery may increase menisci and cartilage damage. PURPOSE: To identify patients at the onset of ACL injury and follow them longitudinally to surgery or final follow-up to describe differences between nonoperative and operative patients and to analyze the effect of delayed reconstruction. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A retrospective review of patients enrolled at a large integrated health care system (IHS) between January 1, 2005, and December 31, 2008, was performed. The study sample included all females ≤12 years old and males ≤14 years old who were evaluated with an ACL injury. The incidence of ACL injuries in each age group was calculated using the number of covered lives by the IHS system per age category as the denominator. Each patient was longitudinally followed using an electronic health record that captures all patient encounters. Every encounter was reviewed for symptoms associated with the index knee, and encounters were considered significant if new-onset pain or swelling was reported. Patients were instructed to restrict their activities while awaiting skeletal maturity to undergo reconstruction by not participating in activities that included any cutting or pivoting movements that would risk injury to the knee. Cartilage and meniscal injuries were recorded for patients who underwent reconstruction. RESULTS: A total of 71 patients were identified during the study period (66 males, 4 females). At the completion of this study, 47 (66.2%) patients had undergone ACL reconstruction, and 24 (33.8%) were being treated nonoperatively. While there were no significant associations between time to surgery and meniscal or cartilage injury, there was a positive association between the number of significant encounters and the likelihood of a combined cartilage and meniscal injury (P = .01). CONCLUSION: This is the first study to measure the incidence of ACL injuries in a skeletally immature population. For patients undergoing ACL reconstruction, an increased number of significant encounters was statistically significantly associated with combined meniscal and cartilage injuries, while increased time from injury to surgery was not significantly associated with additional injuries. In addition, one-third of the patients continued nonoperative treatment without symptoms that warranted surgical interventions during the follow-up period.

Risk factors of subsequent operations after primary anterior cruciate ligament reconstruction.

BACKGROUND: The incidence of nonrevision reoperations after anterior cruciate ligament reconstruction (ACLR) is less commonly studied and quantified. PURPOSE: To describe the incidence of short-term reoperations after primary ACLR for the 4 most common procedures and to evaluate the risk factors associated with these reoperations. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Patients who underwent ACLRs and were enrolled in an ACLR registry between February 2005 and September 2011 were evaluated. First reoperations after primary ACLR performed for the 4 most common procedures (meniscal procedures, cartilage procedures, hardware removal procedures, and arthrofibrosis procedures) were the primary end points of the study. Patient, surgical, surgeon, and hospital risk factors associated with reoperations were evaluated, and Cox regression models were employed. Hazard ratios (HRs) and 95% confidence intervals (CIs) are reported. RESULTS: A total of 14,522 ACLRs were identified. The patients had a mean age of 29.4 ± 11.5 years and were mostly male (63.3%) and white (48.3%). The mean follow-up was 1.9 ± 1.5 years (range, 0-6.7 years), and the median time to reoperation was 301 days (interquartile range, 172-515 days). The reoperation rate per 100 person-years of follow-up was 1.1 for meniscal reoperations, 0.3 for cartilage reoperations, 0.4 for hardware removal reoperations, and 0.4 for arthrofibrosis reoperations. Meniscal repair at the index ACLR was a significant risk factor for subsequent meniscal procedures (HR, 4.19; 95% CI, 3.10-5.67). Sports medicine fellowship training of the surgeon (HR, 2.17; 95% CI, 1.01-4.62) and older patient age (≤17 vs ≥26 years) (HR, 0.32; 95% CI, 0.12-0.81) were significant risk factors for cartilage reoperations. Use of allografts (HR, 1.90; 95% CI, 1.10-3.30) and female sex (HR, 1.75; 95% CI, 1.16-2.64) were risk factors for hardware removal reoperations. Female sex (HR, 2.48; 95% CI, 1.66-3.71) and prior surgery (HR, 3.02; 95% CI, 1.39-6.53) were risk factors for subsequent surgery for arthrofibrosis. CONCLUSION: Overall short-term reoperation rates after ACLR are relatively low. Risk factors for subsequent surgery vary depending on the type of surgery evaluated. Some of the risk factors observed for reoperations include previous meniscal repair, female sex, allografts, prior surgery, older patient age, and being operated on by a sports medicine fellowship-trained surgeon.

Sport-specific injury pattern recorded during anterior cruciate ligament reconstruction.

BACKGROUND: Anterior cruciate ligament (ACL) injuries are more commonly seen with certain cutting and pivoting sports. However, injury patterns associated with these sports have not been well described. PURPOSE: (1) To describe the patient demographics and injury pattern at the time of ACL reconstruction (ACLR) by activities that lead to ACL injuries and (2) to estimate the association of activities at the time of injury with the odds of isolated ACL injuries as well as with meniscus, cartilage, and multiligament injuries diagnosed at the time of ACLR. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: This study combined 2 ACLR registry cohorts, from Norway and the United States, from 2004 to 2011. A cohort of 10,958 primary ACLRs was included. The most prevalent sports activities at the time of injury were the following: soccer, skiing, American football, basketball, and team handball. The end points were the concurrent injury patterns at the time of ACLR: isolated ACL, meniscus, cartilage, and multiligament injuries. RESULTS: All sports were compared with the most prevalent injury mechanism: soccer. Skiing injuries were 1.13 (95% confidence interval [CI], 1.01-1.27) times more likely to result in isolated ACL tears, 2.05 (95% CI, 1.01-4.16) times more likely to result in posterior cruciate ligament tears, 1.94 (95% CI, 1.51-2.49) times more likely to result in medial collateral ligament (MCL) tears, and 1.73 (95% CI, 1.38-2.17) times more likely to result in multiligament injuries. Athletes playing American football were 2.72 (95% CI, 1.32-5.62) times more likely to have MCL tears. Those injured playing basketball were 1.28 (95% CI, 1.06-1.54) times more likely to have lateral meniscus tears, 1.23 (95% CI, 1.01-1.51) times more likely to have cartilage damage, and 1.38 (95% CI, 1.11-1.72) times more likely to have meniscus and cartilage injuries. Athletes injured playing team handball were less likely to have MCL tears (odds ratio [OR], 0.68; 95% CI, 0.46-0.99) and more likely to have lateral meniscus injuries (OR, 1.27; 95% CI, 1.10-1.48). CONCLUSION: Injury patterns were associated with certain sports. Compared with soccer, American football has a higher likelihood of resulting in multiligament injuries, whereas basketball has a higher likelihood of resulting in cartilage and lateral meniscus injuries. Injury patterns seen at the time of surgery may reflect the forces applied to the knee by the specific sports performed.

Analysis of 16,192 anterior cruciate ligament reconstructions from a community-based registry.

BACKGROUND: Orthopaedic registries have shown value in tracking and surveillance of patients, implants, and outcomes associated with procedures. No current anterior cruciate ligament reconstruction registry (ACLRR) exists in the United States. PURPOSE: To describe the current cohort captured by an institutional ACLRR and describe the outcomes observed in the registered patients and how findings from the ACLRR are disseminated. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: The anterior cruciate ligament reconstructions (ACLRs) registered between February 2005 and September 2011 by 244 surgeons in 48 medical centers were evaluated. The ACLRR collected data intra- and postoperatively using paper forms and electronic medical records. The ACLRR cohort was longitudinally followed and outcomes were prospectively ascertained. Outcomes (ie, revisions, subsequent operations, venous thromboembolism, and surgical site infections) were adjudicated via chart review. Descriptive statistics are used to describe the cohort and Kaplan-Meier curves to evaluate survival. RESULTS: During the study period, 16,192 ACLRs (15,101 primary and 1091 revisions) with a median follow-up of 1.6 years (interquartile range, 0.7-2.8 years) were registered. Male patients received 64% of both primary and revision ACLRs. The mean age at surgery was 29.5 years (SD, 11.4 years) for primary and revision reconstructions. Cartilage injuries were noted in 25.2% of primary and 37.5% of revision ACLRs, and meniscal injuries were identified in 60.8% and 53.2%, respectively. Autografts were used in 57.6% of primary ACLRs and 20.9% of revisions. Allografts were used in 42.4% of primaries and 78.8% of revisions. In primary ACLR, the most common femoral and tibial fixation types were interference screws (42.2% and 79.7%, respectively). Fixation type distribution was nearly identical in primaries and revisions. Of the primary ACLRs, 3.7% had subsequent operations on the same knee and 1.7% on the contralateral knee. Deep surgical site infection developed in 0.3% of primaries and 0.8% of revisions. Symptomatic deep vein thromboses were seen in 0.2% of both primaries and revisions. The overall revision rate was 1.7%. Lower rates of graft survival were identified in younger patients and those with allografts. CONCLUSION: Large, community-based ACLRRs are useful in informing participating surgeons of current treatment practices, prevalence of concurrent injuries, and outcomes associated with the procedures. Information from the ACLRR can be used to develop interactive patient and surgeon tools that can be used to optimize patient care.

Anterior cruciate ligament reconstruction in patients with open physes: early outcomes.

Both nonoperative and operative treatments for anterior cruciate ligament (ACL) deficient knees in skeletally immature patients have reported potentially negative outcomes. This study describes primary ACL reconstruction patients with open physes and their concurrent injuries and evaluates whether these patients are at a higher early risk of revision and reoperation than closed physes patients. A retrospective analysis of prospectively collected data was performed. Patients were identified using an ACL Reconstruction Registry. Summary statistics comparing open and closed physes patients of similar ages in regard to patient characteristics and incidence of early revision and reoperation are provided. Adjusted Cox regression models assessed risk of early revision and reoperation for open physes patients. Of 1,867 patients identified, 232 (12.4%) patients had open physes and 1,635 (87.6%) patients had closed physes. Patients with open physes were younger, less likely to be women, and had less medial meniscal injuries than closed physes patients. No significant differences were observed in cartilage injury, overall menisci injury and repair, and early revision and reoperation rate. According to the our results, no significant differences in risk of early revision or early reoperation in open physes compared with closed physes patients when adjusting for age were observed, nor were there any reoperations for physeal closure.