Close to 30% of the surgical causes of readmission within 90 days post-total knee arthroplasty (TKA) and nearly half of those occurring in the first 2 years are caused by instability, arthrofibrosis, and malalignment, all of which may be addressed by improving knee balance. Furthermore, the recently launched Comprehensive Care for Joint Replacement (CJR) initiative mandates that any increase in post-acute care costs through 90-days post-discharge will come directly from the bundle payment paid to providers. Post-discharge costs, including the cost of readmissions for complications are one of the largest drivers of the 90-day cost of care. It is hypothesized that balanced knees post-TKA will lower the true provider costs within the 90-day bundle. Cost, outcomes and resource utilization data were collected from three independent surgeons pre- and post- adoption of intraoperative technology developed to provide real-time, quantitative load data within the knee. In addition, data were collected from Medicare claims, hospital records, electronic medical records (EMR), clinical, and specialty databases. The cohorts consisted of 932 patients in the pre-adoption group and 709 patients in the post-adoption group. These 2 groups were compared to the CMS national average data from 291,201 cases. The groups were controlled for age, sex, state, and BMI with no major differences between cohorts. The cost factors considered were the length of hospital stay, physician visits and physical therapy visits in addition to post-operative complications (e.g., manipulation under anesthesia (MUA) and aseptic revision).Introduction
Methods
Soft tissue balance and alignment have long been known to play an essential role in the long-term success of primary total knee arthroplasty (TKA). Until recently balance was confirmed based on intra-operative feel and experience. In this study we analyzed short-term outcomes of cruciate retaining TKA (CR-TKA) performed with a smart tibial trial device (STT), which provides real-time, intra-operative compartmental load and rotational congruency readings, to a comparable cohort of patients receiving conventional TKA where the same surgeon balanced the compartments based on feel and experience. Seventy patients received CR-TKA with STT and were matched to one-hundred and eighty non-STT consecutive controls using the same anesthesia, surgical approach, and post-operative rehabilitation and pain management protocol. Both groups were evaluated preoperatively and then post-operatively at three months and one year using Short Form 12 (SF12) and the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) questionnaires. T-tests were used to compare average scores within each cohort, as well as between the two cohorts, for each time interval. The average age and BMI for the STT cohort were 70.9 ± 9.2 years and 29.8 ± 6.1 kg/m2. Operation length was seen to be 12.0 minutes greater for the STT cohort compared to the conventional cohort (p = 0.0012). The average difference in pressure between medial and lateral compartments was 8.30, 11.49, and 8.65 lbs at 10°, 45°, and 90° respectively. Only 10 cases had a difference greater than 15 lbs between compartments. At 3 months, the STT cohort had significantly higher average function scores on the WOMAC (p=0.046) and higher change from baseline pain scores on the WOMAC (p=0.0016). When scores were stratified into the top 50% and the bottom 50% and the coronal balance was compared, SF12 pain scores and WOMAC function scores at 1 year in the top 50% had greater coronal balance indicated by pressure differences ≤ 15 lbs (p<0.002) Given the results of this case-control study, we conclude that STT can indeed help the surgeon balance compartmental loads and femoral-tibial rotational congruency and lead to improved short-term physical and functional outcomes in primary CR-TKA.
Traditional medial soft tissue release for balancing of the varus knee in total knee arthroplasty can lead to an inconsistent reduction in medial tension. The purpose of this study is to establish whether sequential needle puncturing of the medial collateral ligament (MCL) can be a safe and predictable method for medial release. Total knee prostheses were implanted in 14 cadaveric specimens by a single surgeon. Medial tension was measured in flexion and extension by a pressure sensor with implants in place, and calipers after removal of implants and gap distraction under constant tension. Measurements were performed after each of 5 sets of 5 punctures of the MCL with an 18-gauge needle and following 5 transverse perforations with an 11-blade. A consistent valgus force was applied after each set of MCL punctures with a pneumatic cylinder. Pearson's correlation was used to compare pressure sensor measurement with gap distance measurement under tension. The pressure as detected by the sensor after each set of 5 punctures was analyzed by a repeated measures two-way ANOVA and a Tukey multiple comparisons test to determine a significant decreases between puncture sets. The pressure sensor device correlated more closely with systematic tissue release (r=0.59 for % change from baseline) than did measurements of gap increase under tension (r= −0.22). All knees had ≤5mm of medial opening with up to 25 needle punctures. Two knees had <5mm of medial opening in flexion after blade perforation. The mean pressure decreases in 90 degrees flexion, mid-flexion and extension were 11.2, 9.4 and 9.9 lbs respectively after 5 needle punctures and 8.1, 11.5 and 9.6 lbs between 5 and 15. Significant pressure decreases were seen after 5 and 10 needle punctures and again after blade perforation (p<0.05) Needle puncture of the deep and superficial MCL leads to a significant and reliable decrease in medial tension over the first 15, with diminishing effect up to 25 punctures. This method may be employed when up to 20 lbs reduction in medial pressure is desired. Blade perforation after needle puncture should be approached with caution.
Total hip arthroplasty (THA) is extremely effective in treating debilitating arthritic conditions of the hip. With the many modular prosthetic designs available, surgeons can now precisely construct mechanical parameters such as femoral offset (FO). Although several studies have investigated relationships between offset choice and hip abductor strength, hip range of motion, and prosthetic wear rate, there is scarce data on the effect of FO on pain and functional outcomes following THA. The objective of this study was to assess the effect of restoring FO (within varying degrees compared to the contralateral non-diseased hip [CL]) on physical function, mental well-being, pain, and stiffness outcomes as measured by the Short Form 12 Health Survey (SF-12) and Western Ontario and McMaster University Osteoarthritis Index (WOMAC) at post-operative follow-up. We prospectively collected data on 249 patients that underwent unilateral THA with no or minimal disease of the contralateral hip. Baseline data collection included: age, gender, diagnosis, femoral head size, type of stem, and pre-operative SF-12 and WOMAC scores. Post-operative SF-12 and WOMAC scores were recorded during annual follow-up visits. Post-operative FO was retrospectively measured on standard anteroposterior (AP) pelvis radiographs and compared to FO of CL. FO was measured as the perpendicular distance from the femoral head center of rotation to the anatomic axis of the femur with appropriate adjustments made for image magnification. Patients were categorized into one of three groups: decreased femoral offset (dFO, less than −5 mm compared to CL), normal femoral offset (nFO, between −5 and +5 mm of CL), and increased femoral offset (iFO, greater than +5 mm compared to CL).Introduction:
Methods:
Unicompartmental knee arthroplasty (UKA) has been proven to be an effective treatment for degenerative joint disease confined to a single tibiofemoral compartment. Recently, UKAs have been performed with robotic-arm assistance (RAA) devices to build and improve upon previous computer-assisted navigation. As a pilot study, we have analyzed short term outcomes for a series of robotic-arm assisted medial UKAs and compared them to a comparable cohort of traditionally instrumented medial UKAs. Ninety-eight fixed-bearing medial UKAs were isolated in our prospective data collection database for short-term analysis for this study. Included patients completed pre and post-operative Short Form 12 version 1 Health Survey (SF12), Western Ontario and McMaster University Outcome Scores (WOMAC), and Knee Society Function Score (KSFS) questionnaires. Forty-eight RAA UKAs were performed using the MAKO RIO system with Restoris implants, and fifty manual UKAs were performed with the Zimmer® Unicompartmental High-Flex Knee System (ZUK).Introduction:
Methods:
Indications for UKA for isolated osteoarthritis of the knee remain controversial. 229 UKA that were performed at our institution were evaluated for which factors was associated with a poor outcome. BMI > 35 was correlated with lower KSS scores than patients with BMI < 35. In contrast to prior reports, patients younger than 60 years old had higher scores than patients 60 years and older at 2 years. Women had an unacceptably high short-term revision rate for any reason of 6.5%. Popularity for UKA has increased, and a more in depth investigation of predictors of poor outcomes demonstrates that younger patients appear to have better results. Obese patients continue to improve up to 2 years after surgery and should not be precluded from undergoing UKA.
The study is a prospective series of the functional outcomes of total knee arthroplasty (TKA) with a novel bi-cruciate stabilizing prosthesis (BCS TKA) compared to a Posterior stabilized (PS) TKA. Between 2008 and 2012, 63 BCS TKA were performed on 56 patients (71 knees) and 54 patients underwent 56 PS TKA with a primary diagnosis of degenerative osteoarthritis, all performed by a single surgeon. Patients completed the Short-Form 12 and WOMAC Index questionnaires pre-operatively and post-operatively at 3 months, 1 year, and 2 years with range of motion determined in the office setting. Regarding the BCS knees, significant improvements in post-operative range of motion were noted, and results of the WOMAC pain component were promising at all intervals tested. However, measures of overall knee function including the WOMAC physical function and stiffness scores in addition to Knee Society Functional Scores saw a slight decline during the second post-operative year. Results from the PS knee implants showed similar trends, and no statistically significant differences were found between the two cohorts throughout functional follow-up; however the ranges of motions appear to be increased in the BCS knee cohort.
