Effect of Posterior Osteophytes on Total Knee Arthroplasty Coronal Soft Tissue Balance: Do They Matter?

BACKGROUND: Achieving coronal plane balance in total knee arthroplasty (TKA) is of paramount importance. There is concern that obtaining balancing before removal of posterior osteophytes may lead to asymmetrical extension balance once removed. We hypothesized that there is a particular posterior osteophyte size and location that does not result in significant change in coronal gap balancing. METHODS: In this study of 245 robotic arm-assisted TKAs, the size and location of posterior osteophytes were obtained from preoperative computer tomography scans. Gap measurements at 10°-25° and 90° flexion after removal of medial and lateral osteophytes, before and after posterior osteophyte removal and bone resection were compared with respect to the size and location of posterior osteophytes. RESULTS: The largest size posterior osteophytes measured >10 mm in 8.2% of cases, 5-10 mm in 34.7%, <5 mm in 23.7%, and 23.7% had no osteophytes. The mean osteophyte size was 5.7 mm. The cohorts with and without posterior osteophytes were both found to have significant but similar changes in all gaps after osteophyte removal and bone resection (mean 0.8-1.4 mm, P < .0001 and mean 0.7-1.7 mm, P < .0001, respectively). Osteophyte size and location had no significant effect on the change in postresection gaps. This included osteophytes greater than 10 mm, but their incidence was small. CONCLUSION: There is a small significant change in gaps between initial assessment and subsequent TKA bone resections, with or without posterior osteophytes. Our study found that where the surgeon thoroughly removes the medial and lateral osteophytes on initial exposure, posterior osteophytes <10 mm can be ignored during initial knee coronal balancing.

Global Budget Revenue on a Single Institution's Costs, Outcomes, and Patient Quality Metrics in Patients Undergoing Total Knee Arthroplasty.

BACKGROUND: Maryland was granted a waiver to implement a Global Budget Revenue (GBR) reimbursement model. Statewide results for combined medical and surgical services have been reported for fiscal years 2015 and 2016. A paucity of studies exists exploring the change in care costs and outcomes for total knee arthroplasty (TKA) recipients under GBR. This study aims to assess the effects of GBR on cost of care and resource utilization related to TKA at a single institution before and after GBR. METHODS: The Maryland Center for Medicare and Medicaid Services database was used to find Medicare patients who underwent TKA at a single institution before (2012-2013) and after (2014-2015) GBR. A total of 150 and 161 TKAs were performed in 2012 and 2015. Cost differences were compared for each inpatient care episode, postacute care period, and readmissions. We also evaluated differences in length of stay, discharge disposition, and complication rates. RESULTS: Mean inpatient cost was significantly lower in 2015 vs 2012 (P = .0014); however, analysis of postacute costs showed a nonsignificant increase in price between years (P = .1008). We demonstrated significant increase in home health (P < .0001) and significant decrease in acute rehabilitation (P = .0481). Durable medical equipment costs significantly decreased (P = .0087). CONCLUSION: We demonstrate lower mean inpatient costs since GBR initiation. We reveal increased mean postacute care costs, which may be due to increased acuity for patients needing postacute care. Our results show nonsignificant reductions in length of stay, complications, and increased rate of home discharge, suggesting GBR may be effective in orchestrating reduced costs for TKA at high-volume institutions.

An Analysis of Centers for Medicare & Medicaid Service Payment in Maryland: Can a Global Budget Revenue Model Save Money in Lower Extremity Arthroplasty?

BACKGROUND: Maryland is the only state utilizing the Global Budget Revenue (GBR) model to reduce costs. The purpose of this study is to evaluate whether the GBR payment model effectively reduced the following: (1) costs of inpatient hospital stays; (2) post-acute care costs; (3) lengths of stay (LOS); (4) readmission rates; and (5) discharge disposition in patients who underwent primary total hip and knee arthroplasty (THA and TKA). METHODS: We evaluated the Maryland Centers for Medicare & Medicaid Service database for THAs and TKAs performed at 6 hospitals 1 year prior to (2012) and after the initiation of GBR (2015). We compared differences in costs for each inpatient care episode, post-acute care periods (total costs, acute rehabilitation, short-term nursing facility, home health, durable medical equipment), readmissions, LOS, and discharge disposition. RESULTS: Hospitals had a significant reduction in mean inpatient care costs for THA and TKA (P < .0001). There was a significant reduction in total post-acute care costs following THA (P < .001). Home healthcare had a significant increase in cost following THA and TKA (P < .0001). There was a significant reduction in durable medical equipment costs for THA (P < .0001). There was a significant decrease in LOS for THA and TKA (P < .0001). There was a significant increase in patients discharged home (THA, P = .0262; TKA, P = .0058). CONCLUSION: The Maryland healthcare model may be associated with a reduction in inpatient and post-acute care costs. Furthermore, implementation of GBR may result in reductions in LOS and readmission rates.

Global Budget Revenue on a Single Institution's Costs and Outcomes in Patients Undergoing Total Hip Arthroplasty.

BACKGROUND: The state of Maryland was granted a waiver by the Center for Medicare and Medicaid Services to implement a Global Budget Revenue (GBR) reimbursement model. This study aims to compare (1) costs of inpatient hospital stays; (2) postacute care costs; (3) lengths of stay (LOS); and (4) discharge disposition who underwent primary total hip arthroplasty at a single Maryland-based orthopedic institution before and after the implementation of GBR. METHODS: The Maryland Center for Medicare and Medicaid Services database was queried to obtain all Medicare patients who underwent total hip arthroplasty at a single institution before and after the implementation of GBR. We compared the differences in costs for the following: inpatient care, the postacute care period, and readmissions. In addition, we evaluated differences in LOS, discharge disposition, and complication rates. RESULTS: There was a significant decrease in inpatient costs ($26,575 vs $23,712), an increase in mean home health costs ($627 vs 1608), and a decrease in mean durable medical equipment costs ($604 vs $82) and LOS (2.92 days vs 2.33 days). There was an increase in discharge to home rates (72.3% vs 78.9%) and a decrease in discharge to acute rehabilitation (4.3% vs 1.8%) CONCLUSION: Under the GBR model, our institution experienced significant cost savings during the inpatient and postacute care episodes. Thus, GBR may serve as a viable solution to reducing costs to Medicare for high-volume arthroplasty institutions with a large Medicare population. Multicentered studies are needed to verify our results.

The Difficult Primary Total Knee Arthroplasty.

Primary total knee arthroplasty (TKA) for the treatment of knee arthritis has substantially increased over the past decade. Because of its success, the indications for primary TKA have expanded to include younger patients who are more active, elderly patients who have multiple comorbidities, and patients who have more complex issues, such as posttraumatic arthritis and severe deformity. TKA also has been used to salvage failed unicondylar arthroplasty and osteotomies about the knee. Exposure may be challenging and outcomes may not be as successful in patients with soft-tissue contractures, such as a stiff knee, who undergo TKA. Bone graft or augments may be required to correct deformity and attain proper knee alignment in patients who have a substantial varus or valgus deformity. TKA is somewhat challenging in patients who have deformity, bone loss, contracture, or multiple comorbidities, or have had prior surgery; therefore, it is necessary for surgeons to be aware of some general principles that may help minimize complications and improve outcomes.

The Economic Impact of Periprosthetic Infections After Total Hip Arthroplasty at a Specialized Tertiary-Care Center.

BACKGROUND: Periprosthetic infections after total hip arthroplasty represent an increased risk for patient morbidity and mortality, and an increased economic burden. The purpose of this study was to compare a group of patients who had periprosthetic infections after total hip arthroplasty to a matched group of patients who underwent primary total hip arthroplasty in terms of the associated costs, length of hospitalization, and number of readmissions (within 1 year). METHODS: Between 2007 and 2011, 16 consecutive infected patients were matched to 32 noninfected patients (1:2 ratio). RESULTS: The mean episode cost, length of hospitalization, and median readmissions was significantly higher in the infected group when compared to the matched cohort: $88,623 vs $25,659, 7.6 vs 3.29 days, and 2 vs 0, respectively. CONCLUSION: Periprosthetic infections after THA resulted in an increased episode cost by approximately 3-fold, mean hospitalization period 2-fold, and led to a higher median number of readmissions.

Histopathological Evaluation of the Anterior Cruciate Ligament in Patients Undergoing Primary Total Knee Arthroplasty.

This study assessed gross and histopathological ACL changes in arthritic knees (n=174) undergoing total knee arthroplasty. Histopathological changes were assessed and graded as absent (0), mild (1), moderate (2), or marked (3). These were correlated to demographic and clinical factors, and radiographic evaluations. The ACL was intact in 43, frayed in 85, torn in 15, and absent in 31 knees. Eighty-five percent had histological changes. Overall, there were significant associations between greater age and BMI, and histological changes. Grade IV knees had significantly greater calcium pyrophosphate deposits, microcyst formation, and number of pathologic changes. These correlations may aid decision-making when determining suitability for unicompartmental or bicruciate-retaining arthroplasties, though further studies should correlate these histological findings to mechanical and functional knee status.

How to Approach a Recalled Dual Modular Hip Implant: An Update.

BACKGROUND: The aim of this study was to provide an update on the "Modular taper junction corrosion and failure: how to approach a recalled total hip arthroplasty implant" (Pivec et al JOA 2014) publication. METHODS: We performed a comprehensive review of the literature in English, with search terms referencing to the diagnosis, management, and outcomes of patients who underwent total hip arthroplasty with a recalled dual modular hip implant. RESULTS: Based on this review and the new guidelines by the American Academy of Orthopedic Surgeons and the Hip Society, we propose an updated algorithm for the diagnosis and management of patients with these recalled implants. CONCLUSION: When encountering patients with these prostheses, it is imperative to take a step-by-step approach to evaluate whether patients are having potential complications. We hope that this has further clarified the appropriate steps that need to be carried out when confronted with these recalled devices.

Bilateral Symmetrical Comparison of Femoral and Tibial Anatomic Features.

BACKGROUND: Variability in morphologic features of the human lower extremity within and across populations has been reported, but limb asymmetry within individuals is often overlooked. For example, in 19 studies of version of the lower extremity in the literature, 6 document asymmetry in the population, but none of these reports document asymmetry in an individual. The aim of this study was to identify the (a)symmetry and quantify variability in the tibiae and femora of matched pairs of limbs. More specifically, using a computed tomography scan database tool, we (1) identified (a)symmetry between paired left and right legs for angulation, version, and alignment features and (2) calculated the percentage of paired limbs with >1° of (a)symmetry for each evaluated parameter. METHODS: Computerized axial tomographic scans (<1.0 mm slices) from bilateral lower limbs of 361 skeletally mature subjects without bone pathology were prospectively acquired. Bones were segmented and morphologic features were measured. RESULTS: Angular features are symmetric left to right, but rotational features are not, with 7° of mean asymmetry in femoral anteversion (range: 0°-23°) and 3° of asymmetry in tibial version (range: 0°-8°). CONCLUSIONS: This study disproves the hypothesis that human limbs are absolutely symmetric, confirming instead that there is asymmetry in version between left and right paired limbs. Surgeons strive for symmetry in lower extremity reconstruction, and they often compare side to side in outcome studies, believing that normal limbs are absolutely symmetric when this is not necessarily true. These assumptions concerning lower extremity symmetry need to be reassessed.

Can We Really "Feel" a Balanced Total Knee Arthroplasty?

BACKGROUND: Balancing techniques in total knee arthroplasty are often based on surgeons' subjective judgment. However, newer technologies have allowed for objective measurements of soft tissue balancing. This study compared the use of sensor technology to the 30-year surgeon experience regarding (1) compartment loads, (2) soft tissue releases, and (3) component rotational alignments. METHODS: Patients received either sensor-guided soft tissue balancing (n = 10) or manual gap balancing (n = 12). Wireless, intraoperative sensor tibial inserts were used to measure intracompartmental loads. The surgeon was blinded to values in the manual gap-balancing cohort. In the sensor cohort, the surgeon was unblinded, and implant trials were placed after normal releases were performed to guide further ligament releases after femoral and tibial resections, as needed. Load measurements were taken at 10°, 45°, and 90°. RESULTS: The sensor cohort had lower medial and lateral compartment loading at 10°, 45°, and 90°. The sensor group had lower mean differences in intercompartment loading at 10° (-5.6 vs -51.7 lbs), 45° (-9.8 vs -45.9 lbs), and 90° (-4.3 vs -27 lbs) compared to manually balanced patients. There were 10 additional soft tissue releases in the sensor cohort (2 initial ones before sensor use), compared to 2 releases in the gap-balanced cohort. In the gap-balanced cohort, tibial trays were positioned at a mean 9° external rotation, compared to a mean 1° internal rotation in the sensor-guided cohort. CONCLUSION: Sensor-balanced total knee arthroplasties provide objective feedback to perform releases and potentially improve knee balancing and rotational alignment. Future work may clarify whether these changes are beneficial for our patients.

Cementless Tapered Femoral Stems for Total Hip Arthroplasty in Octogenarians.

BACKGROUND: The use of cementless femoral components has become the standard in younger patients due to increased implant survivorship and decreased loosening. However, it remains controversial whether these femoral stems can provide comparable results in elderly patients. Therefore, our purpose was to compare the (1) incidence of revisions; (2) clinical outcomes; (3) incidence of postoperative blood transfusions; and (4) differences in complications between the 2 cohorts. METHODS: Seventy-four consecutive patients (78 hips) aged 80 years or older, who underwent primary total hip arthroplasty using a cementless, tapered, femoral stem were retrospectively compared with a matched cohort of 76 patients (78 hips) who were less than 80 years. Mean age was 83 years (range, 80-91 years) vs 59 years (range, 17-79 years) for the matched group. Minimum follow-up was 2 years. Revision rates, clinical outcomes using the Harris Hip Score, incidences of complications, and postoperative transfusion rates were evaluated. RESULTS: In the octogenarian cohort, the aseptic survivorship was 99%, compared with 95% in the matched group. There were 2 aseptic loosenings (2.6%): 1 femoral implant loosening (1.3%) and 1 acetabular loosening, but only 1 revision was performed, as one of the patients declined revision surgery. In the matched cohort, there were 6 revisions (7.7%). There were no significant differences in revision rates between the 2 cohorts, and no significant differences in final Harris Hip Score scores. The incidence of blood transfusion in the study group was 42% vs 19% in control group (P < .01). CONCLUSION: The use of cementless, tapered, femoral stems yielded excellent results in the octogenarian group, although adequate patient preoperative optimization is necessary given the significantly higher transfusion incidence.

A Meta-Analysis of Transcutaneous Electrical Nerve Stimulation for Chronic Low Back Pain.

OBJECTIVE: Transcutaneous electrical nerve stimulation (TENS) may provide a safe alternative to current side-effect-heavy narcotics and anti-inflammatories utilized in chronic low back pain. Therefore, we performed a meta-analysis to evaluate the efficacy of TENS for the treatment of chronic low back pain. MATERIALS AND METHODS: We included randomized controlled trials (RCTs), cohort studies, and randomized crossover studies on TENS for the management of low back pain. We utilized a visual analogue scale (VAS) for pain as our primary outcome. Effectiveness of treatment was quantified using improvement in outcome scores for each study. Of the studies that met the criteria, 13 allowed for calculation of weighted mean differences in pain reduction. We used a random model effect to evaluate changes in pain produced by the intervention. RESULTS: Included were nine level I and four level II, encompassing 267 patients (39% male) who had a mean follow-up of seven weeks (range; 2 to 24 weeks). The mean duration of treatment was six weeks (range; 2 to 24 weeks). The standardized mean difference in pain from pre- to post-treatment for TENS was 0.844, which demonstrated significant improvement of TENS on pain reduction. When subdividing treatment duration, patients that were treated for < 5 weeks had significant effects on pain, while those treated for > 5 weeks did not. CONCLUSION: Treatment of chronic low back pain with TENS demonstrated significant pain reduction. The application of TENS may lead to less pain medication usage and should be incorporated into the treatment armamentarium for chronic low back pain.

Is the use of thin, highly cross-linked polyethylene liners safe in total hip arthroplasty?

PURPOSE: Due to the high number of total hip arthroplasties (THA) revised due to instability, the use of large femoral heads to reduce instability is justifiable. It is critical to determine whether or not large femoral heads used in conjunction with thin polyethylene liners lead to increased wear rates, which can lead to osteolysis. Therefore, by using validated wear-analysis software, we evaluated linear wear rates in a consecutive cohort of patients who underwent primary THA with thin polyethylene liners. METHODS: All patients were selected from a consecutive, prospectively collected database of 241 THAs performed at a single institution by two fellowship-trained joint-reconstruction surgeons between July 2007 and June 2011. These patients were 1:1 matched to a cohort of patients who had conventional-thickness polyethylene liners. RESULTS: No significant differences were observed between linear wear rates of thin or conventional-thickness liners. The Kaplan-Meier survivorship for both cohorts was 100 %, and no cases of polyethylene fracture were observed in either cohort. CONCLUSIONS: Our results suggest that according to a mean follow-up of 4 years, the use of thin liners in THA is promising. Longer follow-up is required to assess whether these outcomes are observed later.

What Host Factors Affect Aseptic Loosening After THA and TKA?

BACKGROUND: Aseptic loosening is the most common cause for revisions after lower-extremity total joint arthroplasties, however studies differ regarding the degree to which host factors influence loosening. QUESTIONS/PURPOSE: We performed a systematic review to determine which host factors play a role in the development of clinical and/or radiographic failure from aseptic loosening after (1) THA and (2) TKA. METHODS: Two searches on THA and TKA, respectively, using four electronic databases (EMBASE, CINAHL Plus, PubMed, and Scopus) were conducted. We identified a total of 209 reports that encompassed nine potential host factors affecting aseptic loosening. Inclusion criteria for consideration of scientific clinical reports were that 20 or more patients were involved, with more than 1-year followup, with at least three studies pertaining to each factor, and at least six of the Methodological Index for Non-randomized Studies criteria met, and with raw data for odds ratio (OR) calculations. Twenty-one studies (16 THA studies with 45,779 hips and five TKA studies with 288 knees, respectively) were used to calculate weighted OR and CIs (using the random effects theory) and study heterogeneity for four different host factors in THAs (male sex, high activity level, obesity defined as BMI≥30 kg/m2, and current or former tobacco use) and one factor in TKA (BMI≥30 kg/m2), which were placed in a forest plot. RESULTS: For THA, male sex (OR, 1.39; 95% CI, 1.22-1.58; p=0.001) and high activity level (University of California Los Angeles [UCLA] activity score≥8 points; OR, 4.24; 95% CI, 2.46-7.31; p=0.001) were associated with aseptic loosening. However, obesity (OR, 1.01; 95% CI, 0.73-1.40; p=0.96), and tobacco use (OR, 1.96; 95% CI, 0.43-8.97; p=0.39) were not associated with an increased risk of aseptic loosening after THA with the numbers available. For TKA, we found no host factors associated with loosening. In particular, obesity (BMI≥30 kg/m2) was not associated with aseptic loosening with the numbers available (OR, 2.28; 95% CI, 0.60-8.62; p=0.22). CONCLUSIONS: Patients undergoing a lower-extremity total joint arthroplasty who engage in impact sports should be counseled regarding their potential increased risk of aseptic loosening; however, given the weak evidence available, we believe that higher-level studies are necessary to clearly define the risk factors, particularly with newer-generation constructs. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Does Co-Existing Lumbar Spinal Canal Stenosis Impair Functional Outcomes and Activity Levels after Primary Total Hip Arthroplasty?

Degenerative lumbar spinal stenosis (LSS) is a cause for substantial morbidity in the elderly population: many often undergo total hip arthroplasty for associated hip arthritis. With a matched cohort we investigated the effect of co-existing LSS on aseptic survivorship, functional outcomes, activity levels, overall subjective physical and mental health status, and satisfaction rates in patients undergoing primary THA. The aseptic-implant survivorship was similar in LSS and non-stenosis cohort. Although both cohorts significantly improved, the LSS cohort achieved lower improvements in HHS, UCLA, SF-36 physical, and satisfaction rates than the matched non-stenotic cohort. Surgeons should consider cautioning patients with LSS that although they can expect relief of their arthritic symptoms following THA, they may continue to expect limitations in function, physical-status, activity-levels, and satisfaction rates.

Long-Term Survivorship and Clinical Outcomes Following Total Knee Arthroplasty.

Total knee arthroplasty (TKA) is one of the most successful commonly performed orthopedic procedures; as such, the purpose was to assess the long-term outcomes and survivorship of primary TKAs with a dual-radius prosthesis. We evaluated 125-patients (145-knees), with a mean age of 63 years (37-90 years) for a mean 11-year follow-up (10-13 years). Outcomes were assessed with KSS, UCLA, SF-36, satisfaction scores, and aseptic survivorship analysis. At 10-year follow-up, the UCLA (6-points), KSS objective (84-points) and functional (73-points), SF-36 physical (41-points) and mental (51-points), and patient satisfaction (14-points) scores were reported to be good to excellent. The 10-year Kaplan-Meier survivorship rate was 99%; one TKA demonstrated radiographic loosening. At a minimum 10-year follow-up, this device demonstrated satisfactory outcomes and outstanding aseptic-survivorship rates.

A Prospective, Longitudinal Study of Outcomes Following Total Knee Arthroplasty Stratified by Gender.

This study aimed to compare temporal trends in outcomes between men and women following TKA. A database of 272 TKAs at 7 years follow-up were evaluated for survivorship, functional, activity, and quality of life outcomes. Evaluation of implant survivorship, KSS scores, and ROM showed no significance differences between men and women, but both functional KSS scores and LEAS showed that men had significantly higher functional scores. The SF-36 physical component was found to be significantly better in men at multiple time points, whereas, the mental component was significantly better in men at pre-operative and 2 years. Both men and women benefit from TKA, however, men have higher levels of function and activity both prior to and after TKA than women.

Strength and Functional Improvement Using Pneumatic Brace with Extension Assist for End-Stage Knee Osteoarthritis: A Prospective, Randomized trial.

Pneumatic unloader bracing with extension assists have been proposed as a non-operative modality that may delay the need for knee surgery by reducing pain and improving function. This prospective, randomized trial evaluated 52 patients who had knee osteoarthritis for changes in: (1) muscle strength; (2) objective functional improvements; (3); subjective functional improvements; (4) pain; (5) quality of life; and (6) conversion to total knee arthroplasty (TKA) compared to standard of care. Patient outcomes were evaluated at a minimum 3 months. Braced patient's demonstrated significant improvements in muscle strength, several functional tests, and patient reported outcomes when compared to the matched cohort. These results are encouraging and suggest that this device may represent a promising alternative to standard treatment methods for knee osteoarthritis.

A Current Review of Mechanical Compression and Its Role in Venous Thromboembolic Prophylaxis in Total Knee and Total Hip Arthroplasty.

Interest in mechanical compression for venous thromboembolic disease prophylaxis has increased over the last several years because of concerns related to bleeding complications associated with chemoprophylaxis. However, the research evaluating compression is clearly not definitive. Therefore, this review aims to: (1) summarize methods of compression; (2) compare AAOS, ACCP, and SCIP guidelines; and (3) make recommendations regarding usage. Below-the-knee devices have demonstrated the most efficacy with multiple guidelines recommending usage. Efficacy and compliance may be improved with the use of mobile devices.

Determining Health-Related Quality-of-Life Outcomes Using the SF-6D Preference-Based Measure in Patients Following Total Knee Arthroplasty.

The SF-6D, a health-related quality-of-life measure, assigns value to patients' perception of their health. We determined SF-6D values of 844 TKA patients, deduced clinical relevance of value changes using effect size, and compared these to clinical and functional improvements 6weeks, 3months, and 1 through 5years post-operatively. The SF-6D significantly improved at all follow-ups after 6weeks. The effect size indicated clinical relevance at every follow-up. The KSS improved at all follow-ups (+43, +51, +56, +57, +57 points), and LEAS scores improved at follow-ups after 6weeks (+1 point at 3months, +2 points thereafter), correlating with SF-6D changes. Deducing utility scores facilitates cost analyses, allowing clinicians to deduce quality-adjusted life-years and economic impacts of treatments.