Tadashi T. Funahashi

Incidence of atypical nontraumatic diaphyseal fractures of the femur

Bisphosphonates reduce the rate of osteoporotic fractures in clinical trials and community practice. “Atypical” nontraumatic fractures of the diaphyseal (subtrochanteric or shaft) part of the femur have been observed in patients taking bisphosphonates. We calculated the incidence of these fractures within a defined population and examined the incidence rates according to duration of bisphosphonate use. We identified all femur fractures from January 1, 2007 until December 31, 2011 in 1,835,116 patients older than 45 years who were enrolled in the Healthy Bones Program at Kaiser Southern California, an integrated health care provider. Potential atypical fractures were identified by diagnostic or procedure codes and adjudicated by examination of radiographs. Bisphosphonate exposure was derived from internal pharmacy records. The results showed that 142 patients had atypical fractures; of these, 128 had bisphosphonate exposure. There was no significant correlation between duration of use (5.5 ± 3.4 years) and age (69.3 ± 8.6 years) or bone density (T‐score −2.1 ± 1.0). There were 188,814 patients who had used bisphosphonates. The age‐adjusted incidence rates for an atypical fracture were 1.78/100,000/year (95% confidence interval [CI], 1.5–2.0) with exposure from 0.1 to 1.9 years, and increased to 113.1/100,000/year (95% CI, 69.3–156.8) with exposure from 8 to 9.9 years. We conclude that the incidence of atypical fractures of the femur increases with longer duration of bisphosphonate use. The rate is much lower than the expected rate of devastating hip fractures in elderly osteoporotic patients. Patients at risk for osteoporotic fractures should not be discouraged from initiating bisphosphonates, because clinical trials have documented that these medicines can substantially reduce the incidence of typical hip fractures. The increased risk of atypical fractures should be taken into consideration when continuing bisphosphonates beyond 5 years.

The International Consortium of Orthopaedic Registries: Overview and Summary

FDA Post-Market Efforts and Interest in Orthopaedics The United States Food and Drug Administration (FDA) Center for Devices and Radiological Health (CDRH) monitors both mandatory and voluntary post-market reporting to identify adverse events and problems associated with medical devices. Although the manufacturers of medical devices are required to report deaths, injuries, and malfunctions directly to the FDA, the device users are required to report these events to the manufacturer and are required to report only deaths to the FDA. Voluntary reporting systems such as the MedWatch program, the MAUDE (Manufacturer and User Facility Device Experience) database, and the MedSun (Medical Product Safety Network) enhanced surveillance network provide nationwide medical device surveillance in the U.S. However, these reporting systems have important weaknesses, such as incomplete, inaccurate, or nonvalidated data, reporting biases related to event severity, concerns that reporting may result in adverse publicity or litigation, and general underreporting of events. Most importantly, denominator data are missing, which makes evaluation of the incidence or prevalence of a safety-related event impossible. The FDA’s interest in orthopaedic device safety and in the development of infrastructure for enhanced safety monitoring is natural and timely; the lack of such safety evidence is particularly troubling for the most commonly used implants. Over 700,000 joint replacements involving implantable devices are conducted annually in the U.S. alone, and the annual volume is projected to increase twofold for hip joint replacements and sevenfold for knee joint replacements, to a total of more than 3 million annually, in just the next twenty years. Moreover, these surgical procedures are expected to become more expensive, with costs tripling in just the next five years. Despite remarkable advancements in orthopaedics, including new devices and improved surgical techniques, the value of many therapeutic devices has not been established in clinical trials or in real-world settings. Several factors contribute to this shortcoming: (1) rapidly changing device technology coupled with an enormous number of devices on the market; (2) the need for large numbers of patients and long-term follow-up to adequately evaluate the primary safety end point, which is longterm device failure or need for revision; and (3) the need for prospective data collection, planning, and substantial funding to evaluate short and long-term patient-reported outcomes, which are the primary effectiveness end points. The poor state of research and the resulting inability to learn about a device’s benefits, its potential harms, and the balance between them hinder decision-making by the FDA and other stakeholders such as the Centers for Medicare & Medicaid Services (CMS) and commercial insurers.

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.

Are Meniscus and Cartilage Injuries Related to Time to Anterior Cruciate Ligament Reconstruction

Background: Functional instability after anterior cruciate ligament injury can be successfully treated with ligament reconstruction. However, the associated meniscus and cartilage lesions often cannot be repaired and may have long-term detrimental effects on knee function. Purpose: The authors used the large database within the Kaiser Permanente Anterior Cruciate Ligament Reconstruction Registry to evaluate time to surgery, age, and gender as risk factors for meniscus and cartilage injury and associations with meniscus repair rates in patients. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A retrospective review of the Kaiser Permanente Anterior Cruciate Ligament Reconstruction Registry was performed. The associations between time to surgery, age, and gender with meniscus and cartilage lesions and meniscus repair were analyzed using binary logistic regression modeling to calculate odds ratios (ORs) while adjusting for potential confounding variables. Results: A total of 1252 patients met the inclusion criteria. The risk of medial meniscus injury increased only with time to surgery (6–12 months: OR = 1.81, 95% confidence internal [CI] 1.29-2.54, P = .001; and >12 months: OR = 2.19, 95% CI 1.58-3.02, P < .001). The risk of lateral meniscus injury decreased only with female gender (OR = 0.65, 95% CI 0.51-0.83, P = .001). The risk of cartilage injury increased with age (OR = 1.05 per year, 95% CI 1.04-1.07, P < .001) and time to surgery >12 months (OR = 1.57, 95% CI 1.12-2.20, P = .009), but decreased with female gender (OR = 0.71, 95% CI 0.54-0.92, P = .009). Medial meniscus repairs relative to medial meniscus injury decreased with increasing time to surgery (3-6 months: OR = 0.61, 95% CI 0.37-1.00, P = .050; and >12 months: OR = 0.41, 95% CI 0.25-0.67, P < .001) and increasing age (OR = 0.96 per year, 95% CI 0.94-0.98, P < .001). Conclusion: Increased risk of medial meniscus injury and decreased repair rate were strongly associated with increasing time to surgery. Increased risk of cartilage injury was associated with increasing age, increasing time to surgery, and male gender.

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.

Incidence of Postoperative Anterior Cruciate Ligament Reconstruction Infections Graft Choice Makes a Difference

Background: Infections after anterior cruciate ligament reconstruction (ACLR) can be devastating. Hamstring tendon autografts may be more susceptible to infections than other graft types. Purpose: To determine the incidence of surgical site infections (SSIs) in a large sample of patients who underwent ACLR and to evaluate the risk of superficial and deep SSIs associated with grafts used for ACLR. Study Design: Cohort study; Level of evidence, 2. Methods: All primary ACLRs performed between February 2005 and September 2010 registered in the Kaiser Permanente ACLR registry were included in the study. The graft types evaluated included the bone–patellar tendon–bone (BPTB) autograft, hamstring tendon autograft, and allograft (all types). The main end point of the study, SSIs (deep and superficial), was prospectively ascertained using an electronic screening algorithm and adjudicated by the principal investigator. Descriptive statistics were used to describe the cohort, and logistic regression models were used to evaluate the likelihood of an infection. Results: There were 10,626 cases that fit the study criteria. The overall cohort was 64% male, mean age was 29 ± 11 years, and mean body mass index (BMI) was 27 ± 5 kg/m2. The overall incidence of SSIs was 0.48% (n = 51), with 17 (0.16%) superficial infections and 34 (0.32%) deep infections. Hamstring tendon autografts (n = 20; 0.61%) had the highest incidence of deep SSIs of the graft types (BPTB autograft, n = 2 [0.07%]; allograft, n = 12 [0.27%]; P < .001). After adjusting for age, sex, and BMI, the likelihood of a patient with a hamstring autograft having a deep SSI was 8.24 times higher (95% CI, 1.91-35.55; P = .005) than someone receiving a BPTB autograft. The risk of infections in allografts was not statistically significantly higher than BPTB autografts. Conclusion: The overall SSI rate after ACLR was 0.48%. Deep SSIs were identified in 0.32% of the ACLR cases and superficial SSIs in 0.16%. An 8.2-times higher risk of SSIs was observed in hamstring tendon autografts compared with BPTB autografts. No difference in SSI incidence was identified between allografts and BPTB autografts. Surgeons should bear in mind that although the overall infection rates after ACLR are low, there is an increased risk of deep infections with hamstring tendon autografts.

Comparison of Community-Based ACL Reconstruction Registries in the U.S. and Norway

INTRODUCTION Joint registries have demonstrated value as a resource for the study of large numbers of patients, providing the opportunity to study rare occurrences and identify early failures of surgical procedures. Anterior cruciate ligament (ACL) reconstruction registries have been established in Norway and the U.S. In this study, we compared the preoperative characteristics of the Norwegian National Knee Ligament Registry (NKLR) and the Kaiser Permanente Anterior Cruciate Ligament Reconstruction Registry (KP ACLRR) cohorts. METHODS A cross-sectional comparison of the NKLR and KP ACLRR cohorts registered between 2005 and 2010 was performed. Aggregate level data including preoperative patient characteristics, mechanisms of injury, preoperative Knee Injury and Osteoarthritis Outcome Score (KOOS), intraoperative findings, and adjusted revision rates were shared between the two registries, and a descriptive analysis was conducted. RESULTS During the study period, 10,468 primary ACL reconstructions were entered in the NKLR and 10,394, in the KP ACLRR. The age at the time of surgery was similar between the two cohorts (twenty-seven years in the NKLR versus twenty-eight years in the KP ACLRR), although the KP ACLRR had a higher proportion of males (65% versus 58%, p < 0.001). The revision rate per follow-up year was 0.9% in the NKLR and 1.5% in the KP ACLRR. Soccer was the most common mechanism of injury in both registries (40.0% in the NKLR and 26.6% in the KP ACLRR). The preoperative KOOS was statistically different, but the difference was not clinically relevant (defined as a change of >10 points). A higher prevalence of meniscal tears was seen in the KP ACLRR (61% versus 49%, p < 0.001). CONCLUSIONS Baseline findings are so congruent between the NKLR and the KP ACLRR cohorts that comparisons between these two registries will likely provide information to the orthopaedic community that can be generalized.

Kaiser Permanente Implant Registries Benefit Patient Safety, Quality Improvement, Cost-Effectiveness

BACKGROUND In response to the increased volume, risk, and cost of medical devices, in 2001 Kaiser Permanente (KP) developed implant registries to enhance patient safety and quality, and to evaluate cost-effectiveness. METHODS Using an integrated electronic health record system, administrative databases, and other institutional databases, orthopedic, cardiology, and vascular implant registries were developed in 2001, 2006, and 2011, respectively. These registries monitor patients, implants, clinical practices, and surgical outcomes for KPs 9 million members. Critical to registry success is surgeon leadership and engagement; each geographical region has a surgeon champion who provides feedback on registry initiatives and disseminates registry findings. RESULTS The registries enhance patient safety by providing a variety of clinical decision tools such as risk calculators, quality reports, risk-adjusted medical center reports, summaries of surgeon data, and infection control reports to registry stakeholders. The registries are used to immediately identify patients with recalled devices, evaluate new and established device technology, and identify outlier implants. The registries contribute to cost-effectiveness initiatives through collaboration with sourcing and contracting groups and confirming adherence to device formulary guidelines. Research studies based on registry data have directly influenced clinical best practices. CONCLUSIONS Registries are important tools to evaluate longitudinal device performance and safety, study the clinical indications for and outcomes of device implantation, respond promptly to recalls and advisories, and contribute to the overall high quality of care of our patients.

Incidence of Symptomatic Venous Thromboembolism After Elective Knee Arthroscopy

BACKGROUND Knee arthroscopy is the most commonly performed orthopaedic procedure in the United States and is usually considered to be a low-risk procedure. The purposes of this study were to describe the incidence of symptomatic deep venous thrombosis, symptomatic pulmonary embolism, and mortality after elective knee arthroscopy performed without thromboembolic prophylaxis, as well as to investigate the association of age, sex, procedure type, and oral contraceptive use with the odds of developing a venous thromboembolism. METHODS A retrospective cohort study of elective arthroscopic knee procedures during a twenty-seven-month period (January 1, 2006, through March 31, 2008) was performed with use of the administrative database of a large health maintenance organization. Use of ICD-9-CM (International Classification of Diseases, Ninth Revision, Clinical Modification) procedure codes for arthroscopic surgery identified 21,794 arthroscopic knee procedures. The occurrence of a symptomatic deep venous thrombosis or pulmonary embolism within ninety days after surgery was identified by reviewing administrative and electronic medical record data for inpatient, outpatient, urgent care, and emergency encounters. Mortality and the cause of death were captured with use of electronic medical records, Social Security Administration Death Master Files, and county death certificates. Patient charts were reviewed for confirmation of the deep venous thrombosis, pulmonary embolism, or death. Patients who had a history of a venous thromboembolism or who had received anticoagulation therapy within fourteen days prior to the index surgery were excluded. RESULTS The study cohort comprised 20,770 patients who met the inclusion criteria. Fifty-one patients (0.25%; 95% confidence interval, 0.18% to 0.31%) developed a deep venous thrombosis, and thirty-five (0.17%; 95% confidence interval, 0.11% to 0.22%) developed a pulmonary embolism. The incidence of venous thromboembolism was higher in patients who were fifty years of age or older (0.51% compared with 0.34% in younger patients), and the incidence in female patients was higher if they had been prescribed oral contraceptive medication (0.63% compared with 0.30% in female patients with no such prescription). No differences in the incidence of deep venous thrombosis or pulmonary embolism on the basis of sex or arthroscopic procedure code were noted. Nine patients (0.04%) died within ninety days of surgery, although only one death was confirmed to have resulted from a pulmonary embolism. CONCLUSIONS The ninety-day incidence of symptomatic venous thromboembolism after elective knee arthroscopy was relatively low, with a 0.25% incidence of deep venous thrombosis and a 0.17% incidence of pulmonary embolism. The overall ninety-day mortality after arthroscopic knee surgery was 0.04%.

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.