Liposomal Bupivacaine vs Plain Bupivacaine in Periarticular Injection for Control of Pain and Early Motion in Total Knee Arthroplasty: A Randomized, Prospective Study.

BACKGROUND: The use of multimodal pain regimens has been shown to be an effective technique for the treatment of postoperative pain after total knee arthroplasty. Periarticular injections, of both short-acting and long-acting anesthetics, have emerged as an additional method of providing significant improvement in postoperative pain relief. The purpose of this study is to compare the efficacy of periarticular injection using long-acting vs short-acting preparations. METHODS: A randomized, prospective study of 80 consecutive patients was performed comparing liposomal bupivacaine vs plain bupivacaine periarticular injection. The primary outcomes included pain relief, total narcotic usage, and completion of physical therapy goals, specifically range of motion. RESULTS: No significant improvements were noted between liposomal bupivacaine and plain bupivacaine injection groups in overall pain reduction, range of motion, or total narcotic usage. At 24 hours, small statistically significant differences in physical therapy pain scores were noted with liposomal bupivacaine vs plain bupivacaine and control patients, but these differences did not persist at later time points. Both preparations demonstrated statistically significant improvements in range of motion when compared to historical controls, but no differences were noted between preparations. CONCLUSION: Overall, minimal significant differences were noted between liposomal bupivacaine and plain bupivacaine at early and late time points. Both preparations of periarticular injection demonstrated superiority over control pain regimens but were relatively equivalent to one another in direct comparison.

Trunnion Failure of the Recalled Low Friction Ion Treatment Cobalt Chromium Alloy Femoral Head.

BACKGROUND: Gross trunnion failure (GTF) is a rare complication in total hip arthroplasty (THA) reported across a range of manufacturers. Specific lots of the Stryker low friction ion treatment (LFIT) anatomic cobalt chromium alloy (CoCr) V40 femoral head were recalled in August 2016. In part, the recall was based out of concerns for disassociation of the femoral head from the stem and GTF. METHODS: We report on 28 patients (30 implants) with either GTF (n = 18) or head-neck taper corrosion (n = 12) of the LFIT CoCr femoral head and the Accolade titanium-molybdenum-zirconium-iron alloy femoral stems. All these cases were associated with adverse local tissue reactions requiring revision of the THA. RESULTS: In our series, a conservative estimate of the incidence of failure was 4.7% (n = 636 total implanted) at 8.0 ± 1.4 years from the index procedure. Failures were associated with a high-offset 127° femoral stem neck angle and increased neck lengths; 43.3% (13 of 30) of the observed failures included implant sizes outside the voluntary recall (27.8% [5 of 18] of the GTF and 75.0% [8 of 12] of the taper corrosion cases). Serum cobalt and chromium levels were elevated (cobalt: 8.4 ± 7.0 µg/mL; chromium: 3.4 ± 3.3 µ/L; cobalt/chromium ratio: 3.7). The metal artifact reduction sequence magnetic resonance imaging demonstrated large cystic fluid collections typical with adverse local tissue reactions. During revision, a pseudotumor was observed in all cases. Pathology suggested a chronic inflammatory response. Impending GTF could be diagnosed based on aspiration of black synovial fluid and an oblique femoral head as compared with the neck taper on radiographs. CONCLUSION: In our series of the recalled LFIT CoCr femoral head, the risk of impending GTF or head-neck taper corrosion should be considered as a potential diagnosis in a painful LFIT femoral head and Accolade titanium-molybdenum-zirconium-iron alloy THA with unknown etiology. Almost half of the failures we observed included sizes outside of the voluntary recall.

Optimizing PROM Implementation in Orthopedic Clinics for Longitudinal Outcome Monitoring: Lessons from a Multisite Study.

BACKGROUND: Systematic patient-reported outcome measure (PROM) collection is challenging for clinics, particularly when patients are not in the office. The Arthritis care through Shared Knowledge (ASK) study deployed multimodal approaches to collect PROMs using a clinical microsystem framework. CONCEPTUAL MODEL: Informed by the clinical microsystem model, the authors coached 12 orthopedic practices to implement shared processes to support best practices for PROM collection and use. Orthopedic sites collected PROMs from new patients before the first office visit; patients completed the PROM from home via an online assessment in a personalized e-mail. Site staff placed follow-up phone reminders. At 6 and 12 months after the visit, PROMs were collected from home, prompted by an e-mail or phone call. PERFORMANCE OUTCOMES: Of the 25,043 new patients identified by clinical sites during the study enrollment, approximately 60% completed a pre-visit PROM-36.6% completed the online PROM after receiving a single automated e-mail, and an additional 31.1% completed the PROM after receiving a text, an e-mail, or a phone call from the staff. The remaining 32.2% of PROMs were collected on arrival at the office. Of patients completing PROMs, 11,140 were eligible to participate in longitudinal collection, and 51.3% consented. Of these, approximately 84% completed a 6-month survey, more than 83% completed a 12-month survey, and more than 91% completed either a 6-month PROM, a 12-month PROM, or both. LEARNING: This study illustrates that a multimodal approach to PROM collection using a clinical microsystem approach sustainably supports PROM completion rates. Further efforts are needed to define strategies to engage all patients in understanding and reporting PROMs to inform their care.

Measurements of acetabular cup position and pelvic spatial orientation after total hip arthroplasty using computed tomography/radiography matching.

This study presents a clinical validation of postoperative measurements of acetabular cup alignment following total hip arthroplasty (THA). The methodology was based on concurrent anatomic three-dimensional (3D) measurements of both the acetabular cup alignment and pelvic orientation, using an original CT/X-ray matching algorithm named Xalign. The subjects were 19 patients who had undergone bilateral THA using CT-based surgical navigation. All patients had postoperative pelvic CT scans and multiple antero-posterior (AP) pelvic X-rays. Using a proprietary software algorithm, the X-rays included in the study were matched with the corresponding postoperative CT scans. The goal of this method was to allow 3D anatomic pelvic and acetabular measurements on two-dimensional AP X-rays. The postoperative cup abduction, version and pelvic flexion angles were determined in three different ways: using CT images directly, applying the Xalign method, and finally by performing conventional (abduction only) measurements on AP pelvic X-rays. The cup orientation measured on CT images was taken as the ground truth. The Xalign measurement errors were defined as the difference between the CT cup values and those obtained by applying the matching method. The mean cup abduction error was 0.85 degrees +/- 1.3 degrees (+/- standard deviation) and the mean version error was 0.01 degrees +/- 1.99 degrees . Conventionally measured cup abduction ranged from 44 degrees to 62 degrees and correlated significantly (p = 0.001, r = -0.5) with pelvic flexion angle, proving the linear negative correlation between pelvic flexion and the error in conventional radiographic cup measurements. The Xalign method offered reasonable accuracy for cup orientation, and allowed cup and pelvic 3D anatomic measurements at different times.

Dose-Associated Changes in Gait Parameters in Response to Exercise Programs after Total Knee Arthroplasty: Secondary Analysis of Two Randomized Studies.

BACKGROUND: Rehabilitation plays an important role to improve the outcomes of total knee arthroplasty (TKA). Evidence about the appropriate dose of exercise to recover gait dysfunction after TKA is limited. We posed the research question: In patients during the post-acute stage after TKA, is increased dose of exercise associated with larger improvements in gait parameters such as step length and single support time? METHODS: This was a secondary analysis from two randomized studies on exercise after TKA to investigate dose-dependence of gait parameters in response to exercise. Participants were 50 years or older who underwent unilateral TKA at least two months prior. They participated in 2 months of supervised exercises followed by 4 months of a home exercise program. The primary outcome was change in gait parameters from baseline to 6 months. Participants were divided in three groups according to the dose of exercise: group 1 (light-to-moderate intensity exercise), group 2 (high intensity + functional exercise), and group 3 (high intensity + functional + balance exercise). Jonckheere-Terpstra test was used to test if the magnitude of changes in gait parameters increased from group 1 to group 3 in an ordered fashion. RESULTS: Increased dose of exercise was associated with progressive increases in step length in the operated-limb (p=0.008) and decreases in step length in the non-operated limb (p=0.011). Increased dose of exercise was associated with ordinal decreases in loading response time (p=0.049) and increases in single-leg support time (p=0.021) on the operated- limb, but not on the non-operated-limb. Increased dose of exercise was associated with decreases in unloading time on the non-operated-limb (p=0.011) but not on the operated-limb (p=0.400). CONCLUSIONS: Significant dose-response of exercise on gait parameters support the promotion of more intensive exercise programs that combine functional and balance training programs after TKA.

Less invasive total hip arthroplasty using navigational tools.

Although traditional total hip arthroplasty offers good visualization of bony landmarks and allows for the accurate orientation and fixation of implants, these benefits are achieved at the expense of extensive soft-tissue dissection and can result in postoperative complications and a delayed return to full function. To address these disadvantages, navigational tools were coupled with a mini-incision technique that allowed accurate bone preparation and orientation of the implant components without direct visualization of the bony landmarks. Additionally, image-guided systems provide three-dimensional information before and during surgery, making it possible to know, in real time, the orientation of implants and to visualize the full bony anatomy. This "computer-enhanced vision" allows surgeons to perform less invasive and eventually minimally invasive total hip arthroplasty with improved accuracy.

Contribution of hip abductor strength to physical function in patients with total knee arthroplasty.

BACKGROUND: Investigating modifiable factors that contribute to functional limitations in patients with total knee arthroplasty (TKA) may guide changes in rehabilitation protocols and improve functional outcomes. Whereas quadriceps muscle weakness has been demonstrated to contribute to functional limitations in TKA, the role of hip abductor weakness has not received attention. OBJECTIVE: The purpose of this study was to determine whether hip abductor strength (force-generating capacity) contributes to physical function beyond what can be explained by quadriceps muscle strength in patients after a TKA. DESIGN: A cross-sectional design was used in the study. SETTING: The study was conducted in a clinical laboratory at an academic center. PATIENTS: Thirty-one people with TKA (74% female; mean age=68 years, SD=8; mean body mass index=31 kg/m(2), SD=5) participated in the study. MEASUREMENTS: Strength of quadriceps muscles and hip abductors was measured using an isokinetic dynamometer. Performance-based physical function was assessed with 4 measures: self-selected walking speed, the Figure-of-8 Walk Test, the Stair Ascend/Descend Test, and the 5-Chair Rise Test. Self-reported physical function was assessed with the Western Ontario and McMaster Universities Osteoarthritis Index Physical Function Subscale. RESULTS: In hierarchical regression models, after accounting for demographic and anthropometric factors, quadriceps muscle strength was associated with performance on the Stair Ascend/Descend Test. After accounting for demographic, anthropometric, and quadriceps strength, hip abductor strength was associated with performance on the Stair Ascend/Descend Test, the Figure-of-8 Walk Test, and the 5-Chair Rise Test. LIMITATIONS: The study design precluded ascertainment of causal relationships. CONCLUSIONS: After TKA, hip abductor strength influenced physical function in participants more than did demographic or anthropometric measures or quadriceps strength. Longitudinal studies with larger samples are warranted. If findings are replicated, they will justify targeting the hip abductors during rehabilitation after TKA.

A balance exercise program appears to improve function for patients with total knee arthroplasty: a randomized clinical trial.

BACKGROUND: Patients with total knee arthroplasty (TKA) have impaired balance and movement control. Exercise interventions have not targeted these impairments in this population. OBJECTIVES: The purposes of this study were: (1) to determine the feasibility of applying a balance exercise program in patients with TKA, (2) to investigate whether a functional training (FT) program supplemented with a balance exercise program (FT+B program) could improve physical function compared with an FT program alone in a small group of individuals with TKA, and (3) to test the methods and calculate sample size for a future randomized trial with a larger study sample. DESIGN: This study was a double-blind, pilot randomized clinical trial. SETTING: The study was conducted in the clinical laboratory of an academic center. PARTICIPANTS: The participants were 43 individuals (30 female, 13 male; mean age=68 years, SD=8) who underwent TKA 2 to 6 months prior to the study. INTERVENTIONS: The interventions were 6 weeks (12 sessions) of a supervised FT or FT+B program, followed by a 4-month home exercise program. MEASUREMENTS: Feasibility measures included pain, stiffness, adherence, and attrition. The primary outcome measure was a battery of physical performance tests: self-selected gait speed, chair rise test, and single-leg stance time. Secondary outcome measures were the Western Ontario and McMaster Universities Osteoarthritis Index and the Lower Extremity Functional Scale. RESULTS: Feasibility of the balance training in people with TKA was supported by high exercise adherence, a relatively low dropout rate, and no adverse events. Both groups demonstrated clinically important improvements in lower-extremity functional status. The degree of improvement seemed higher for gait speed, single-leg stance time, and stiffness in the FT+B group compared with the FT group. LIMITATIONS: Due to the pilot nature of the study, differences between groups did not have adequate power to show statistical significance. CONCLUSIONS: There is a need for conducting a larger randomized controlled trial to test the effectiveness of an FT+B program after TKA.

Patient and family-centered collaborative care: an orthopaedic model.

Despite both longstanding and recent interest in patient-centered care, there are few published models or methods for defining and implementing patient-centered care in the office and hospital setting through a full cycle of care from the patient's perspective. We describe patient- and family-centered collaborative care as a low-technology, systems-based solution to many current problems and suggest ways to provide safe, effective, timely, and efficient health care. We presumed such a patient- and family-centered collaborative care model would provide high quality health care. We prospectively collected data on 618 consecutive patients undergoing THA or TKA within a dedicated patient- and family-centered collaborative care program. We found a high level of patient satisfaction with an overall satisfaction score of 91.4 using the Press Ganey Survey. Infection and mortality rates were 0.3% and 0.1%, respectively. Average length of stay was 2.8 days for TKA and 2.7 days for THA with 91% of all patients being discharged directly home and 93% walking without handheld assistance at the time of discharge. The patient- and family-centered collaborative care model is not just another clinical pathway but a comprehensive systems-based approach that focuses on the full cycle of care while placing patients and their families as the top priority to provide high quality health care.

Functional pelvic orientation measured from lateral standing and sitting radiographs.

We prospectively obtained preoperative and 3-month postoperative lateral pelvic radiographs in the standing and sitting positions from 84 patients who underwent total hip arthroplasty. We measured pelvic orientation (flexion extension) using the anterior pelvic plane as defined by the anterior superior iliac spines and pubic tubercles as references. There was a trend towards upright pelvic alignment when standing, with a mean anterior pelvic plane angle of 1.2 degrees (range, -22 degrees - +27 degrees). In the sitting position the pelvis tended to extend posteriorly, with a mean anterior pelvic plane angle of -36.2 degrees (range, -64 degrees - +4 degrees). There was a wide variation in the arc of pelvic flexion extension as patients moved from standing to sitting, with are of pelvic motion in some patients as mobile as 70 degrees and in others as stiff as 5 degrees. There was no significant variation between males and females or between preoperative and postoperative pelvic flexion extension. There were substantial variations in pelvic orientation when comparing standing and sitting for an individual patient and between different patients. This variation can be unpredictable, and may influence implant alignment and stability after total hip arthroplasty.

Accuracy of pelvic flexion measurements from lateral radiographs.

Variations in pelvic orientation affect preoperative planning decisions, intraoperative navigation, and postoperative measurements. By providing the means to measure pelvic flexion at low cost and reporting pelvic flexion using the standard reference system, a lateral radiograph technique based on the pubic tubercles and anterior superior iliac spines may be useful for studying functional pelvic orientation and functional alignment and for improving accuracy of postoperative measurement. We evaluated the accuracy of this method by synthesizing 50 lateral pelvic radiographs. Six observers performed manual landmark-based pelvic flexion measurements on the resultant radiographs. Pelvic flexion measurement errors were small (0.004 masculine +/- 1.38 masculine). Apart from one outlier with an error of 12.4 masculine, the errors ranged from -4.0 masculine to 3.0 masculine. The data suggest that accurate measurements of pelvic flexion can be made from lateral radiographs with respect to the standard anatomic reference system. However, failure to correctly observe a landmark can introduce large errors. Therefore, the clarity of the relevant landmarks should be considered carefully before applying this technique. Lateral radiographs can be easily acquired and analyzed, making this technique convenient and inexpensive.

Mini-incision technique for total hip arthroplasty with navigation.

This prospective study compares a mini-incision technique and traditional posterior approach for total hip arthroplasty (THA). Thirty-three patients who had undergone a mini-incision THA were matched by diagnosis, gender, average age, and preoperative Harris Hip Score (HHS) to 33 patients who had undergone THA using the traditional posterior approach. The average length of the incision for group 1 was 11.7 cm (range, 7.3-13.0) and for group 2 was 20.2 cm (range, 14.8-26.0). At the 3-month follow-up, patients in the mini-incision group had significant improvement in limp (P<.05) and ability to climb stairs (P <.01) compared with the traditional group. At the 6 month follow-up, the mini-incision group was significantly better in terms of limp (P <.05), distance walked (P<.001), and stairs (P < 0.001). There was no significant difference between groups for pain, function, or range of motion at the 1-year follow-up examination.

Comparison of a mechanical acetabular alignment guide with computer placement of the socket.

We hypothesized that use of mechanical acetabular guides for intraoperative alignment leads to variations between the actual and desired implant orientation. Acetabular implant orientation using only the mechanical guide was studied in 78 patients (82 hips) undergoing primary total hip arthroplasty. A computer-assisted navigation system was used to measure alignment and to monitor the orientation of the pelvis during surgery. When using the mechanical guide, there was significant variation in cup alignment from the desired goal of 45 degrees of abduction and 20 degrees of flexion, and this would have resulted in unacceptable acetabular alignment in 78% of hips. With the support system used, there was significant variability in pelvic orientation during surgery. The mean anteversion of the pelvis was an average of 18 degrees from the optimal orientation. These results show a clear need to develop more reliable tools than were used or anatomically based alignment strategies to provide reproducible and accurate acetabular alignment.