Matthew D. Beal

Can the American College of Surgeons Risk Calculator Predict 30-Day Complications After Knee and Hip Arthroplasty?

Accurate risk stratification of patients undergoing total hip (THA) and knee (TKA) arthroplasty is essential in the highly scrutinized world of pay-for-performance, value-driven healthcare. We assessed the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) surgical risk calculators ability to predict 30-day complications using 1066 publicly-reported Medicare patients undergoing primary THA or TKA. Risk estimates were significantly associated with complications in the categories of any complication (P = .005), cardiac complication (P < .001), pneumonia (P < .001) and discharge to skilled nursing facility (P < .001). However, predictability of complication occurrence was poor for all complications assessed. To facilitate the equitable provision and reimbursement of patient care, further research is needed to develop accurate risk stratification tools in TKA and THA surgery.

The Effect of BMI on 30 Day Outcomes Following Total Joint Arthroplasty

Hip and knee arthroplasty (THA, TKA) are safe, effective procedures with reliable, reproducible outcomes. We aim to investigate obesitys effect on complications following arthroplasty surgery. Using the American College of Surgeons-National Surgical Quality Improvement Program database, 13,250 subjects were stratified into 5 groups based on BMI and matched for gender, age, surgery type and ASA class. Matched, multivariable generalized linear models adjusting for demographics and comorbidities demonstrated an association between elevated BMI and overall (P<0.001), medical (P=0.005), surgical complications (P<0.001), including superficial (P=0.019) and deep wound infection (P=0.040), return to OR (P=0.016) and time from OR to discharge (P=0.003). Elevated BMI increases risk for post-operative complications following total joint arthroplasty.

Preoperative Risk Stratification and Risk Reduction for Total Joint Reconstruction: AAOS Exhibit Selection.

Demand for primary total hip arthroplasty and demand for total knee arthroplasty in the United States are anticipated to grow by 174% and 673%, respectively, over the next twenty years1. Satisfaction rates are good to excellent in most patients2-4. Modern techniques and perioperative care have reduced systemic and local complications5-7. Nevertheless, the risks of major adverse outcomes (2.2% to 7.4%)8-10 and death (0.1% to 0.8%)5,7-9,11-19 remain real. Careful preoperative clearance and targeted therapeutic interventions are necessary to minimize complications. Studies have demonstrated total joint arthroplasty to be a highly cost-effective procedure. Nevertheless, many payers, especially the U.S. Centers for Medicare & Medicaid Services (CMS), have targeted total joint arthroplasty for cost control20. Adoption of a pay-for-performance program by CMS21 has created a zero-sum game to reward overachievers and penalize underachievers. The current literature lacks a detailed, comprehensive approach for risk-stratifying total joint arthroplasty patients and a systematic method for preoperatively allaying these risks. Popular tools such as the American Society of Anesthesiologists (ASA) classification system may be effective in predicting the overall outcome of surgery, but they cannot predict specific complications22 and they do not facilitate further preparatory action23-25. Although medical evaluation should be performed in collaboration with the internist, evidence-based guidelines provide standardization and comprehensiveness. Conditions necessitating postponement or cancellation of total joint arthroplasty are present in approximately 4% of patients26. Complications related to the cardiovascular system represent 42% to 75% of major systemic adverse events and deaths following total joint arthroplasty7,13,27,28, and cardiovascular comorbidities are a significant risk factor for these events14,29. Intramedullary instrumentation …

Do Patients With Insulin-dependent and Noninsulin-dependent Diabetes Have Different Risks for Complications After Arthroplasty?

BackgroundPatients with diabetes are known to be at greater risk for complications after arthroplasty than are patients without diabetes. However, we do not know whether there are important differences in the risk of perioperative complications between patients with diabetes who are insulin-dependent (Type 1 or 2) and those who are not insulin-dependent. Questions/purposes The purpose of our study was to compare (1) medical complications (including death), (2) surgical complications, and (3) readmissions within 30 days between patients with insulin-dependent and noninsulin-dependent diabetes, and with patients who do not have diabetes.MethodsA total of 43,299 patients undergoing THA or TKA between 2005 and 2011 were selected from the American College of Surgeon’s National Surgical Quality Improvement Program’s (ACS-NSQIP®) database. Generalized linear models were used to assess the relationship between diabetes status and outcomes (no diabetes [n = 36,574], insulin dependent [n = 1552], and noninsulin dependent [n = 5173]). Multivariate models were established adjusting for confounders including age, sex, race, BMI, smoking, steroid use, hypertension, chronic obstructive pulmonary disease, and anesthesia type. Post hoc comparisons between patient groups were made using a Bonferroni correction.ResultsPatients who were insulin dependent had increased odds of experiencing a medical complication (OR, 1.6; 95% CI, 1.2–2.0; p < 0.001), as did patients who were noninsulin dependent (OR, 1.2; 95% CI, 1.1–1.4; p< 0.001). An increased likelihood of 30-day mortality was found only for patients who were insulin dependent (OR, 3.74; 95% CI, 1.6–8.5; p = 0.007). However, neither diabetic state was associated with surgical complications. Finally, readmission was found to be independently associated with insulin-dependent diabetes (OR, 1.6; 95% CI, 1.1–2.1; p = 0.023).ConclusionsPatients with insulin-dependent diabetes are most likely to have a medical complication or be readmitted within 30 days after total joint replacement. However, patients who are insulin dependent or noninsulin dependent are no more likely than patients without diabetes to have a surgical complication. Physicians and hospitals should keep these issues in mind when counseling patients and generating risk-adjusted outcome reports.Level of EvidenceLevel III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Single-Dose Adductor Canal Block With Local Infiltrative Analgesia Compared With Local Infiltrate Analgesia After Total Knee Arthroplasty: A Randomized, Double-Blind, Placebo-Controlled Trial.

Background and Objectives A single-dose adductor canal block can provide postoperative analgesia for patients undergoing total knee arthroplasty (TKA). The purpose of this study was to assess postoperative opioid consumption after ultrasound-guided single-injection bupivacaine compared with saline adductor canal block for patients undergoing TKA. Methods After institutional review board approval, written informed consent was obtained from patients (>18 years old) undergoing elective TKA. Subjects were randomized into 2 groups as follows: adductor canal blockade with 10 mL of bupivacaine 0.25% with epinephrine 1:300,000 or 10 mL of normal saline. All patients received a periarticular infiltration mixture intraoperatively with scheduled and patient requested oral and IV analgesics postoperatively for breakthrough pain. Personnel blinded to group allocation recorded pain scores and opioid consumption every 6 hours. Pain burden, area under the numeric rating score for pain, was calculated for 36 hours. The primary outcome was postoperative IV-IM morphine (mg morEq) consumption at 36 hours after surgery. Results Forty (28 women-12 men) subjects were studied. Postoperative opioid consumption was reduced in the bupivacaine 48 (39 to 61) mg morEq compared with saline 60 (49 to 85) mg morEq, difference −12 (−33 to −2) mg morEq (P = 0.03). Pain burden at rest was decreased in the bupivacaine 71 (37 to 120) score · hours compared with saline 131 (92 to 161) score · hours, difference −60 (−93 to −14) score · hours (P = 0.009). Conclusions Adductor canal blockade with bupivacaine 0.25% with epinephrine 1:300,000 effectively reduces pain and opioid requirement in the postoperative period after TKA. Adductor canal blockade is an effective pain management adjunct for patients undergoing TKA.

Design and Cadaveric Validation of a Novel Device to Quantify Knee Stability During Total Knee Arthroplasty

The success of total knee arthroplasty depends, in part, on the ability of the surgeon to properly manage the soft tissues surrounding the joint, but an objective definition as to what constitutes acceptable postoperative joint stability does not exist. Such a definition may not exist due to lack of suitable instrumentation, as joint stability is currently assessed by visual inspection while the surgeon manipulates the joint. Having the ability to accurately and precisely measure knee stability at the time of surgery represents a key requirement in the process of objectively defining acceptable joint stability. Therefore, we created a novel sterilizable device to allow surgeons to measure varus-valgus, internal-external, or anterior-posterior stability of the knee during a total knee arthroplasty. The device can be quickly adjusted between 0 deg and 90 deg of knee flexion. The device interfaces with a custom surgical navigation system, which records the resultant rotations or translations of the knee while the surgeon applies known loads to a patients limb with a handle instrumented with a load cell. We validated the performance of the device by having volunteers use it to apply loads to a mechanical linkage that simulated a knee joint; we then compared the joint moments calculated by our stability device against those recorded by a load cell in the simulated knee joint. Validation of the device showed low mean errors (less than 0.21 ± 1.38 Nm and 0.98 ± 3.93 N) and low RMS errors (less than 1.5 Nm and 5 N). Preliminary studies from total knee arthroplasties performed on ten cadaveric specimens also demonstrate the utility of our new device. Eventually, the use of this device may help determine how intra-operative knee stability relates to postoperative function and could lead to an objective definition of knee stability and more efficacious surgical techniques.

Relationships between varus-valgus laxity of the severely osteoarthritic knee and gait, instability, clinical performance and function.

Increased varus–valgus laxity has been reported in individuals with knee osteoarthritis (OA) compared to controls. However, the majority of previous investigations may not report truly passive joint laxity, as their tests have been performed on conscious participants who could be guarding against motion with muscle contraction during laxity evaluation. The purpose of this study was to investigate how a measure of passive knee laxity, recorded when the participant is under anesthesia, is related to varus–valgus excursion during gait, clinical measures of performance, perceived instability, and self‐reported function in participants with severe knee OA. We assessed passive varus–valgus knee laxity in 29 participants (30 knees) with severe OA, as they underwent total knee arthroplasty (TKA). Participants also completed gait analysis, clinical assessment of performance (6‐min walk (6 MW), stair climbing test (SCT), isometric knee strength), and self‐reported measures of function (perceived instability, Knee injury, and Osteoarthritis Outcome Score (KOOS) a median of 18 days before the TKA procedure. We observed that greater passive varus–valgus laxity was associated with greater varus–valgus excursion during gait (R2 = 0.34, p = 0.002). Significant associations were also observed between greater laxity and greater isometric knee extension strength (p = 0.014), farther 6 MW distance (p = 0.033) and shorter SCT time (p = 0.046). No relationship was observed between passive varus–valgus laxity and isometric knee flexion strength, perceived instability, or any KOOS subscale. The conflicting associations between laxity, frontal excursion during gait, and functional performance suggest a complex relationship between laxity and knee cartilage health, clinical performance, and self‐reported function that merits further study.

Inter-Rater and Intra-Rater Repeatability and Reliability of EOS 3-Dimensional Imaging Analysis Software

BACKGROUND Quantifying ideal component position for the acetabulum and stem during total hip arthroplasty (THA) has been described by many methods. A new imaging method using low-dose digital stereoradiography, the EOS imaging system, is a biplanar low-dose X-ray system that allows for 3-dimensional modeling of lower limbs and semiautomated measurement of pelvic parameters and implant alignment. METHODS Twenty-five patients who underwent primary THA by a single surgeon between October 2014 and December 2014 were retrospectively selected. Only patients with unilateral THA without associated spine pathologies were included, totaling 16 right hips and 9 left hips. There were 8 men and 17 women in the cohort, with a mean age of 67 years (range, 53-82). Three individuals performed measurements of pelvic parameters and implant alignment on 3 separate occasions. An interclass correlation of >0.75 was accepted as evidence of excellent agreement and a confirmation of measurement reliability. RESULTS Before reviewing patient radiographs, 4 pelvic phantom models were analyzed using the EOS 3-dimensional software to verify accuracy. All anatomic and implant measurements performed by the 3 independent reviewers showed interobserver and intraobserver agreement with interclass correlation >0.75. CONCLUSION Three-dimensional modeling of hip implants with the EOS imaging system is a reasonable option for the evaluation of component position after THA.

Improving outcomes in total knee arthroplasty-do navigation or customized implants have a role?

Modern total knee arthroplasty is effective at treating the pain and disability associated with osteoarthritis. The number of total knee replacements done in the USA continues to increase. Despite the great care taken during all of these procedures, some patients remain dissatisfied with their outcome. While this dissatisfaction is likely multifactorial, malalignment of the prosthetic components is a major cause of postoperative complications. A neutral mechanical axis plus or minus 3° is felt to have a positive impact on the survivorship of the prosthesis. Conventional instrumentation has been shown to have a significant number of total knee replacements that lie well outside a neutral coronal alignment. With that in mind, significant effort has been placed into the development of technology to improve the overall alignment of the prosthesis. In order to reduce the number of outliers, several companies have developed cost-effective systems to aid the surgeon in achieving a more predictably aligned prosthesis in all three planes. We will review the literature that is available regarding several of these tools to examine if navigation or custom guides improve outcomes in total knee arthroplasty. Our review supports that while both navigation and custom implants guides seem to be a cost effective way to achieve a predictable mechanical alignment of a total knee prosthesis therefore reducing the number of outliers, the cost may be increased operative times with no perceived difference in patient satisfaction with navigation custom guides.

Estimating patient-specific soft-tissue properties in a TKA knee.

Surgical technique is one factor that has been identified as critical to success of total knee arthroplasty. Researchers have shown that computer simulations can aid in determining how decisions in the operating room generally affect post‐operative outcomes. However, to use simulations to make clinically relevant predictions about knee forces and motions for a specific total knee patient, patient‐specific models are needed. This study introduces a methodology for estimating knee soft‐tissue properties of an individual total knee patient. A custom surgical navigation system and stability device were used to measure the force–displacement relationship of the knee. Soft‐tissue properties were estimated using a parameter optimization that matched simulated tibiofemoral kinematics with experimental tibiofemoral kinematics. Simulations using optimized ligament properties had an average root mean square error of 3.5° across all tests while simulations using generic ligament properties taken from literature had an average root mean square error of 8.4°. Specimens showed large variability among ligament properties regardless of similarities in prosthetic component alignment and measured knee laxity. These results demonstrate the importance of soft‐tissue properties in determining knee stability, and suggest that to make clinically relevant predictions of post‐operative knee motions and forces using computer simulations, patient‐specific soft‐tissue properties are needed.