What is the Value of a Balanced Total Knee Arthroplasty? Getting It Right the First Time.

BACKGROUND: Instability is a leading cause of early failure following total knee arthroplasty (TKA). Enabling technologies can improve accuracy, but their clinical value remains undetermined. The purpose of this study was to determine the value of achieving a balanced knee joint at the time of TKA. METHODS: A Markov model was developed to determine the value from reduced revisions and improved outcomes associated with TKA joint balance. Patients were modeled for the first 5 years following TKA. The threshold to determine cost-effectiveness was set at an incremental cost effectiveness ratio of $50,000/quality-adjusted life year (QALY). A sensitivity analysis was performed to evaluate the influence of QALY improvement (ΔQALY) and Revision Rate Reduction on additional value generated compared to a conventional TKA cohort. The impact of each variable was evaluated by iterating over a range of ΔQALY (0 to 0.046) and Revision Rate Reduction (0% to 30%) and calculating the value generated while satisfying the incremental cost effectiveness ratio threshold. Finally, the impact of surgeon volume on these outcomes was analyzed. RESULTS: The total value of a balanced knee for the first 5 years was $8,750, $6,575, and $4,417 per case, for low, medium, and high-volume surgeons, respectively. Change in QALY accounted for greater than 90% of the value gain with a reduction in revisions making up the rest in all scenarios. The economic contribution of revision reduction was relatively constant regardless of surgeon volume ($500/case). CONCLUSION: Achieving a balanced knee had the greatest impact on ΔQALY over early revision rate. These results can help assign value to enabling technologies with joint balancing capabilities.

Internet-Based Exercise Therapy Using Algorithms for Conservative Treatment of Anterior Knee Pain: A Pragmatic Randomized Controlled Trial.

BACKGROUND: Conservative treatment remains the first-line option, and there is significant medical evidence showing that home-based exercise therapy for the treatment of common causes of knee pain is effective. SimpleTherapy created an online platform that delivers Internet-based exercise therapy for common causes of knee pain. The system is driven by an algorithm that can process the user's feedback to provide an adaptive exercise regimen. This triple-armed, pragmatic randomized pilot was designed to evaluate if this telerehabilitation platform is safe and effective. OBJECTIVE: We hypothesized that a home-based, algorithm-driven exercise therapy program can be safe for use and even improve compliance over the standard of care, the paper handout. METHODS: After an independent internal review board review and approval, the website trial.simpletherapy.com was opened. Once the trial was open for enrollment, no changes to the functionality or user interaction features were performed until the trial had closed. User accrual to the website was done using website optimization and social media postings tied to existence of knee pain. Consent was obtained online through checkboxes with third-party signature confirmation. No fees were charged to any patient. Patients were recruited online from an open access website. Outcomes were self-assessed through questionnaires with no face-to-face clinician interaction. A triple-arm randomized controlled trial was used with arm 1 being a static handout of exercises, arm 2 being a video version of arm 1, and arm 3 being a video-based, algorithm-driven system that took patient feedback and changed the exercises based on the feedback. Patients used household items and were not supervised by a physical therapist or clinician. Patients were reminded at 48-hour intervals to complete an exercise session. RESULTS: A total of 860 users found the trial and initiated the registration process. These 860 were randomized, and the demographic distribution shows the randomization was successful. In all, 70 users completed the 6-week regimen (8.1%): 20 users were in arm 1, 33 users in arm 2, and 17 users in arm 3. There were no adverse events reported in any of the 3 arms. All outcomes were self-assessed. No adverse events were reported during or after the trial. CONCLUSIONS: Because only 8.1% of those who enrolled completed the trial, an intent-to-treat analysis did not reach statistical significance in this pilot trial. However, the completion rates are comparable to those of previous online-only trials. Given an early phase trial, no adverse events were reported. Ongoing data collection continues and will form the basis for further data on the efficacy of this intervention. TRIAL REGISTRATION: Clinicaltrials.gov NCT01696162; https://clinicaltrials.gov/ct2/show/NCT01696162 (Archived by WebCite at http://www.webcitation.org/6lM8jC7Gu).

Percutaneous external fixator pins with bactericidal micron-thin sol-gel films for the prevention of pin tract infection.

Risk of infection is considerable in open fractures, especially when fracture fixation devices are used to stabilize the fractured bones. Overall deep infection rates of 16.2% have been reported. The infection rate is even greater, up to 32.2%, with external fixation of femoral fractures. The use of percutaneous implants for certain clinical applications, such as percutaneous implants for external fracture fixation, still represents a challenge today. Currently, bone infections are very difficult to treat. Very potent antibiotics are needed, which creates the risk of irreversible damage to other organs, when the antibiotics are administered systemically. As such, controlled, local release is being pursued, but no such treatments are in clinical use. Herein, the use of bactericidal micron-thin sol-gel films on metallic fracture fixation pins is reported. The data demonstrates that triclosan (2,4,4'-trichloro-2'-hydroxydiphenylether), an antimicrobial agent, can be successfully incorporated into micron-thin sol-gel films deposited on percutaneous pins. The sol-gel films continuously release triclosan in vitro for durations exceeding 8 weeks (longest measured time point). The bactericidal effect of the micron-thin sol-gel films follows from both in vitro and in vivo studies. Inserting percutaneous pins in distal rabbit tibiae, there were no signs of infection around implants coated with a micron-thin sol-gel/triclosan film. Healing had progressed normally, bone tissue growth was normal and there was no epithelial downgrowth. This result was in contrast with the results in rabbits that received control, uncoated percutaneous pins, in which abundant signs of infection and epithelial downgrowth were observed. Thus, well-adherent, micron-thin sol-gel films laden with a bactericidal molecule successfully prevented pin tract infection.

Saline-coupled bipolar sealing in simultaneous bilateral total knee arthroplasty.

BACKGROUND: The efficacy of saline-coupled bipolar sealing devices in joint arthroplasty is uncertain, and the utility in simultaneous bilateral total knee arthroplasty (TKA) has not been reported. METHODS: This study compares the use of bipolar sealing and conventional electrocautery in 71 consecutive patients. The experimental and control groups were matched for age, sex, body mass index, American Society of Anesthesiologists (ASA) classification, and preoperative hemoglobin. Variables of interest included blood loss, transfusion requirements, and operative characteristics. RESULTS: In comparison to patients treated with conventional electrocautery, those treated with the bipolar sealer were 35% less likely to require transfusion. The median number of transfusions per case was also significantly lower in the experimental group. Hemoglobin change, total blood loss, and length of stay were not significantly different between the groups. The experimental group had longer operative times. CONCLUSIONS: Bipolar sealing shows promise as a blood loss reduction tool in simultaneous bilateral TKA. The marginal savings attributed to reduced transfusion rates with use of the bipolar sealer did not exceed the additional per-case expense of using the device. The decision to use the device with the goal of less blood loss must come with the additional expense associated with its use.

Bactericidal micron-thin sol-gel films prevent pin tract and periprosthetic infection.

Orthopedic injuries constitute the majority of wounds sustained by U.S. soldiers in recent conflicts. The risk of infection is considerable with fracture fixation devices. In this pilot study, we examined the use of unique bactericidal micron-thin sol-gel films on fracture fixation devices and their ability to prevent and eradicate infections. External fixation was studied with micron-thin sol-gel coated percutaneous pins releasing triclosan and inserted medially into rabbit tibiae. A total of 11 rabbits received percutaneous pins that were either uncoated or sol-gel/triclosan coated. Internal fracture fixation was also studied using sol-gel coated intramedullary (IM) nails releasing vancomycin in the intramedullary tibiae. Six sheep received IM nails that were coated with a sol-gel film that either contained vancomycin or did not contain vancomycin. All animals were challenged with Staphylococcus aureus around the implant. Animals were euthanized at 1 month postoperative. Rabbits receiving triclosan/sol-gel coated percutaneous pins did not show signs of infection. Uncoated percutaneous pins had a significantly higher infection rate. In the sheep study, there were no radiographic signs of osteomyelitis with vancomycin/sol-gel coated IM nails, in contrast to the observations in the control cohort. Hence, the nanostructured sol-gel controlled release technology offers the promise of a reliable and continuous delivery system of bactericidals from orthopedic devices to prevent and treat infection.

Periprosthetic fractures around loose femoral components.

The development of periprosthetic fractures around loose femoral components can be a devastating event for patients who have undergone total hip arthroplasty (THA). As indications for THA expand in an aging population and to use in younger patients, these fractures are increasing in incidence. This review covers the epidemiology, risk factors, prevention, and clinical management of periprosthetic femoral fractures. Treatment principles and reconstructive options are discussed, along with outcomes and complications. Femoral revision with a long-stem prosthesis or a modular tapered stem is the mainstay of treatment and has demonstrated good outcomes in the literature. Other reconstruction options are available, depending on bone quality. Surgeons must have a sound understanding of the diagnosis and treatment of periprosthetic femoral fractures.

FDG PET for diagnosing infection in hip and knee prostheses: prospective study in 221 prostheses and subgroup comparison with combined (111)In-labeled leukocyte/(99m)Tc-sulfur colloid bone marrow imaging in 88 prostheses.

PURPOSE: This study aims to assess and compare the value of FDG PET with combined In-labeled leukocyte/Tc-sulfur colloid bone marrow (WBC/BM) imaging for diagnosing infection in hip and knee prostheses. METHODS: In this prospective study, patients with painful hip or knee arthroplasty, who were scheduled to undergo clinical and diagnostic evaluation for prosthesis revision, were included. They have been studied by using FDG PET and WBC/BM scan. This study was institutional review board approved and Health Insurance Portability and Accountability Act compliant. All patients provided written informed consent. RESULTS: A total of 134 hip and 87 knee prostheses, suspected of being either infected or noninfectious loosening, were evaluated. All 221 prostheses underwent FDG PET, whereas both WBC/BM imaging and FDG PET were performed in 88 prostheses. The initial analysis of data from the WBC/BM images demonstrated somewhat suboptimal results compared with those of FDG PET scans on 88 patients. In addition, some patients were not willing to undergo both procedures and therefore participate in this study. Therefore, a decision was made to eliminate WBC/BM imaging from the procedures for the remainder of this research study. This decision was reached partly because of the significant radiation dose delivered from labeled WBC and safety issues related to preparing these labeled cells. Final diagnosis was based on microbiological examinations of the surgical specimens in 125 prostheses and joint aspirations combined with the clinical follow-up of 6 months or more in 86 prostheses. The sensitivity, specificity, positive predictive value, and negative predictive value of FDG PET in hip prostheses were 81.8%, 93.1%, 79.4%, and 94.0%, respectively, and in knee prostheses were 94.7%, 88.2%, 69.2%, and 98.4%, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of WBC/BM imaging in hip prostheses were 38.5%, 95.7%, 71.4%, and 84.6%, respectively, and in knee prostheses were 33.3%, 88.5%, 25.0%, and 92.0%, respectively. In those cases that underwent both FDG PET and WBC/BM imaging, there was a trend (P = 0.0625) toward a higher sensitivity for FDG PET in hip prostheses, whereas other comparisons did not show any significant differences between the 2 imaging modalities. CONCLUSIONS: Based on this study, the diagnostic performance of FDG PET scan in detecting infection in painful hip and knee prostheses is optimal for routine clinical application. Considering the complexity and costs of WBC/BM imaging and related safety issues associated with this preparation, FDG PET seems to be an appropriate alternative for assessing these patients.

Outcomes of long tapered hydroxyapatite-coated stems in revision total hip arthroplasty.

The purpose of this study was to evaluate the outcome of femoral component revisions using a long tapered HA coated femoral revision stem. Between 2001 and 2008, 55 femoral component revisions were performed using this stem. Forty-one patients were available for follow up evaluation at average of 59 months. The clinical results were evaluated using the HHS and serial radiographs were evaluated for loosening. The mean HHS was 71 (range 22-100). Three hips required revision of KAR stem (1 aseptic loosening, 1 infection, 1 limb length discrepancy). Only one prosthesis demonstrated radiographic evidence of subsidence. Our study suggests that long tapered HA coated revision femoral components can provide stable fixation and in-growth in cases where there is good proximal femoral bone stock and favorable canal geometry.

Ceramic-on-ceramic total hip arthroplasty in patients younger than 55 years.

PURPOSE: To review the outcomes of 65 patients younger than 55 years who underwent uncemented total hip arthroplasty (THA) using third-generation ceramic-on-ceramic prostheses. METHODS: Medical records of 30 men and 35 women (80 hips) aged 18 to 55 (mean, 39) years who underwent uncemented THA using third-generation ceramic-onceramic prostheses by a single surgeon were reviewed. 61 THAs used the Reflection cup with the Synergy stem (n=49), Spectron stem (n=7), or Anthology stem (n=5), and 19 THAs used the Trident cup with the Secur-Fit stem. Outcomes were assessed based on the UCLA Activity Score and Harris Hip Score, as well as radiolucency around the implants, malposition, and subsidence on radiographs. Patients were asked about their satisfaction with current activity level (yes/no), activity limitation (no limitation, musculoskeletal limitation, psychological impediments and lack of motivation, and pain or disability of the operative hip), and change in occupational activity level (same or similar, more active, and less active or disability). RESULTS: The mean follow-up period was 54 (range, 24-110) months. Six patients were excluded from the analysis owing to prosthetic failure secondary to ceramic liner fracture after falling (n=2), acetabular component loosening (n=1), intolerable squeak (n=1), periprosthetic fracture (n=1), and instability (n=1). The mean UCLA Activity Score improved from 4.0 (range, 1-10) to 7.7 (range, 2-10) [p<0.001], and the mean Harris Hip Score improved from 52.8 (range, 25-69) to 91.0 (range, 38-100) [p<0.001]. No hip had evidence of subsidence, loosening, or osteolysis. 52 (80%) patients were satisfied with their activity level; 28 (43%) patients reported no activity limitation; and 57 (88%) patients kept the same or similar occupation. CONCLUSION: Ceramic-on-ceramic THA achieved acceptable clinical and radiographic outcomes.

Cement technique for reducing post-operative bursitis after trochanteric fixation.

Post-operative trochanteric bursitis is a known complication secondary to the surgical approach in total hip arthroplasty. This phenomenon may be partially attributable to repetitive microtrauma generated when soft tissues rub against implanted hardware. Significant rates of post-operative trochanteric bursitis have been observed following procedures in which a trochanteric fixation device, such as a bolt-washer mechanism or a cable-grip/claw system, is used to secure the trochanteric fragment after trochanteric osteotomy. We present a simple technique for use with a bolt-washer system or grip plate in which trochanteric components are covered in bone wax followed by a layer of cement to decrease friction and to diminish the risk of post-operative bursitis.

Steinman pin technique for the removal of well-fixed femoral stems.

Femoral stems with the capacity for exuberant bony in-growth, such as hydroxyapatite- or porous-coated stems, pose a challenge in the revision setting if extraction is required. The goal of minimal bone loss is crucial. We present an adjunct technique for the removal of well-fixed femoral stems with the use of Steinman pins.

Bipolar sealing in revision total hip arthroplasty for infection: efficacy and cost analysis.

Saline-coupled bipolar sealing has shown mixed results in primary arthroplasty. However, this technology has not been studied in infected revision total hip arthroplasty (THA), where morbidity is higher and conventional methods of blood management, such as cell salvage, often cannot be used. This case-matched study of 76 consecutive revision THA for infection included an experimental bipolar sealing group and a control group of conventional electrocautery. Groups were matched for gender, body mass index, American Society of Anesthesiologists classification, and surgery type. Total blood loss, intraoperative blood loss, and perioperative hemoglobin drop were significantly less in the experimental group. In addition, operative time was significantly shorter in the experimental group, which translated into gross savings approximately equal to the cost of the device. The decreases in total blood loss and perioperative hemoglobin decline, along with financial savings, may support the use of bipolar sealing in infected revision THA.

Managing massive bone loss after infected total knee arthroplasty with a custom-made spacer.

Periprosthetic infection is an increasingly prevalent and challenging problem in joint reconstruction. We present a technical report of a custom spacer for management of an infected total knee arthroplasty (TKA) and concomitant severe bone loss. The spacer was designed to provide sufficient leg length, soft tissue tension, and limb stability in preparation for ultimate limb reconstruction. This technique and custom spacer serve as an alternative for managing significant bone loss in infected knee arthroplasty.

Porous tantalum patellar components in revision total knee arthroplasty minimum 5-year follow-up.

Revision total knee arthroplasty can be complicated by severe patellar bone loss, precluding the use of standard cemented patellar components. This study evaluated the midterm outcomes of porous tantalum (PT) patellar components. Twenty-three PT components were used in 6 men and 17 women (average age, 62 years). All patellae had less than 10-mm residual thickness. The PT shell was secured to host bone, and a 3-peg polyethylene component was cemented onto the shell. In 2 patients, the PT component was sutured directly to extensor mechanism. Average follow-up was 7.7 years (range, 5-10 years). At follow-up, the Knee Society scores for pain and function averaged 82.7 and 33.3, respectively, whereas the mean Oxford knee score was 32.6. Four patients underwent revision surgery. Survivorship was 19 (83%) of 23 patients. Porous tantalum patellar components can provide fixation where severe bone loss precludes the use of traditional implants. Failures were associated with avascular residual bone and fixation of components to the extensor mechanism.

Prophylactic decompression and bone grafting for small asymptomatic osteonecrotic lesions of the femoral head.

Core decompression and grafting has been shown to relieve pain and possibly prevent disease progression in patients with symptomatic osteonecrosis (ON) of the hip. However, there is a lack of evidence regarding the management of the asymptomatic hip with femoral head ON. The purpose of this study was to evaluate the outcome of core decompression in the asymptomatic hip with ON. We prospectively followed 37 consecutive patients with MRI confirmed ON of the hips that underwent simultaneous bilateral core decompression and bone grafting. Prior to surgery, only one of the hips was symptomatic, and the main indication for surgical decompression of the asymptomatic side was to prevent disease progression. No hip on the asymptomatic side was staged greater than Steinberg IIB classification. Serial radiographs were followed for evidence of disease progression. Six patients were lost to follow-up prior to two years. The remaining 31 patients were followed for an average of 32.6 months. There were 20 men and 11 women with an average age of 40.6 years. Ten patients with asymptomatic hips at the time of surgical decompression had disease progression requiring THA. The mean time to arthroplasty in this group was 15.1 months. Meanwhile, 13 symptomatic hips at the initial surgery progressed to THA at an average of 12.9 months following core decompression. The proportion of hips requiring conversion to THA was similar between the two groups (p=0.30), and the rate of progression to THA was not significantly faster compared to patients with symptomatic hips who subsequently required THA (p=0.18). Core decompression for asymptomatic ON of the femoral head is unpredictable. Based on our results, asymptomatic ON lesions particularly in the setting of bilateral disease should be closely observed and surgery reserved for when symptoms arise.

Autologous blood reinfusion in patients undergoing bilateral total hip arthroplasty.

PURPOSE: To compare the rate and unit of allogeneic blood transfusion in one-stage bilateral total hip arthroplasty (THA) in patients with and without autologous blood reinfusion. METHODS: Records of a consecutive series of 43 men and 33 women aged 25 to 83 (mean, 55) years who underwent one-stage sequential bilateral THA by a single surgeon were reviewed. Their risks of cardiopulmonary complications were minimal. At least 4 weeks prior to surgery, 38 of the patients donated 2 units of autologous blood in 2 stages (one to 2 weeks apart). The remaining 38 patients did not donate blood owing to personal preferences or logistical reasons. All pre-donated autologous blood was transfused back to the patients in the recovery room. Estimated blood loss volume, blood salvaged volume, and complications were recorded, as were pre- and post-operative haemoglobin levels. The 2 groups were compared with respect to the rate and unit of allogeneic blood transfusion. RESULTS: The mean estimated blood loss was 939 (SD, 448; range, 200-2500) ml. The mean volume of blood salvaged was 302 (SD, 196; range, 0-850) ml, representing a collection rate of 32%. In patients with and without autologous blood reinfusion, 16 (42%) and 33 (87%) patients received allogeneic blood transfusion of 0.9 and 2.4 units, respectively (p<0.0001). Four patients developed major cardiopulmonary complications. None had deep venous thrombosis or pulmonary embolism. No complications resulted from blood transfusion. The 2 groups were not significantly different in complication rate (13% vs. 18%, p=0.54) and discharge haemoglobin levels. CONCLUSION: Autologous blood reinfusion was effective in reducing the rate and unit of allogeneic blood transfusion in patients undergoing one-stage bilateral THA.

Prospective results of uncemented tantalum monoblock tibia in total knee arthroplasty: minimum 5-year follow-up in patients younger than 55 years.

A significant increase in younger patients undergoing total knee arthroplasty raises the theoretical concern for revision secondary to micromotion and fixation failure with cemented components. We prospectively studied 100 consecutive tantalum monoblock uncemented tibial components and 312 concurrent cemented controls. Patients younger than 55 years with adequate bone stock were enrolled. This cementless patient group was younger and had higher preoperative functional status. Prostheses were posterior-substituting uncemented femoral and tibial components with a cemented patellar button. Knee Society pain and function scores and radiographs were obtained, and a cost analysis was performed. Knee Society scores were excellent and equivalent beyond 6 months. There was no significant difference in perioperative blood loss, complication rates, or cost. There was a significant decrease in operative time in the uncemented group. Radiographs revealed no failures of ingrowth at last follow-up. There were 3 uncemented group failures, but none were due to failure of fixation. The use of a porous tantalum tibia at minimum 5 years has yielded promising clinical and radiographic results in a younger patient population.

Comparison of surgical outcomes and implant wear between ceramic-ceramic and ceramic-polyethylene articulations in total hip arthroplasty.

The results of a prospective multicenter trial comparing 357 hips randomized to total hip arthroplasty with either ceramic-ceramic or ceramic-polyethylene couplings are presented. No statistically significant difference in clinical outcomes scores between the ceramic-ceramic and ceramic-polyethylene groups was observed at any time interval. The mean linear rate was statistically lower (P < .001) in the ceramic-ceramic group (30.5 µm/year) when compared with the ceramic-polyethylene group (218.2 µm/year). The rates of ceramic implant fracture (2.6%) and audible component-related noise (3.1%) were statistically higher in the ceramic-ceramic group when compared with the ceramic-polyethylene group (P < .05). Lastly, there was no statistically significant difference in the dislocation or revision rate between the groups at the time of last clinical follow-up.