Robotic Arm-assisted Total Hip Arthroplasty Reduces Postoperative Trochanteric Bursitis and Changes in Hip Offset.

We investigated the effect of robotic assistance in a postoperative change in hip offset and the incidence of trochanteric bursitis among total hip arthroplasty (THA) patients. As part of a retrospective study of a consecutive series of patients over a 3-year period, 211 patients (102 traditional; 109 robotic) between 2013 and 2016 who underwent posterior-lateral THA were reviewed. Hip offset was measured on preoperative and postoperative anterior-posterior (AP) pelvis radiographs. The absolute change in total hip offset was higher in patients undergoing non-robotic THA than in patients undergoing robotic THA (5.98 ± 4.47 mm vs 4.33 ± 3.98 mm; p = 0.008). The rate of symptomatic trochanteric bursitis (p = 0.02) and cortisone injection was higher in non-robotic THA patients than in robotic THA patients (p = 0.002). Robotic arm-assisted THA is associated with a decreased postoperative change in hip offset, incidence of symptomatic trochanteric bursitis, and bursal steroid injections. (Journal of Surgical Orthopaedic Advances 32(4):112-116, 2023).

Varus-Valgus Constraint in Primary Total Knee Arthroplasty: A Short-Term Solution but Will It Last?

BACKGROUND: Prostheses with varus-valgus constraint (VVC) are increasingly utilized in primary total knee arthroplasty (TKA) to address coronal malalignment and instability though little is known regarding the association between added constraint and aseptic loosening. We sought to systematically review the literature for reports of VVC in primary TKA and meta-analyze clinical results and implant survival. METHODS: PubMed was searched using broad terms to identify articles reporting VVC in primary TKA. Any article reporting clinical or survival outcomes was included. Clinical scores, close to 2 years postoperatively were converted to standardized mean differences, and the latest survival estimates were weighted using the inverse of their variance and meta-analyzed. RESULTS: Three hundred ninety-two search results were reviewed identifying 30 relevant articles reporting on 3620 knees in total. The estimate for the improvement in clinical scores postoperatively was 3.1 standard deviations (95% confidence interval 2.6-3.6). The estimate for implant revision slowly increased from 1% at 2 years to 2% at 6 years and then began to increase more rapidly beyond this point. The estimated revision rate was 9% by 12 years and 28% by 20 years. This revision rate estimate was stable with and without the inclusion of outlying studies. CONCLUSION: VVC in primary TKA is associated with significant clinical improvement without significant risk of early failure. Meta-regression estimates raise concerns for significant revision risk with extended follow-up, especially beyond 5 years. In the absence of new data, VVC should continue to be used cautiously in the primary TKA.

Stratifying Venous Thromboembolism Risk in Arthroplasty: Do High-Risk Patients Exist?

BACKGROUND: While there are many possible complications associated with total joint arthroplasty (TJA), venous thromboembolism (VTE) is both frequent and potentially severe. Despite this importance, there are inconsistent recommendations for prophylaxis based on patient risk factors. METHODS: A predictive model was constructed to compare low-molecular-weight heparin(LMWH) and aspirin (ASA) for prevention of VTE-associated complications following TJA.The model used risks from prior prophylaxis studies to estimate the risk of developing a symptomatic deep vein thrombosis, pulmonary embolism, thrombocytopenia, and operative or nonoperative site bleeding. We also evaluated the progression to 4 possible final health states: postphlebitis syndrome, intracranial hemorrhage, death, or baseline health. Within published ranges, we selected assumptions that were favorable to LMWH such that these analyses represent a best case scenario for LMWH or an alternative more aggressive low-molecular-weight heparin alternative (LMWHA). Events and outcomes were assigned quality-adjusted life-year (QALY) losses according to prior studies to determine the effect on patients' outcomes for ASA and LMWHA prophylaxis. RESULTS: Assessing VTE risk populations from 0.2% to 2% with life expectancies ranging from 5 to 40 years postoperatively, patients with a risk ratio less than 3.7 showed increased expected QALY with ASA compared to LMWHA. For patients with a baseline VTE risk of 1% and a 15 year life expectancy, a risk ratio of 13.4 was needed to identify patients that would benefit from LMWHA. With life expectancy increased to 30 years, the risk ratio needed to idetify these patients was 7.4. CONCLUSION: Patients undergoing TJA should receive ASA chemoprophylaxis in nearly all situations, unless the patient has a significantly increased VTE risk compared to the baseline population and a long life expectancy.

The Association of Opioid Utilization and Patient Satisfaction Following Outpatient Orthopaedic Surgery: More May Not Be Better.

Postoperative analgesia remains an important area of research in orthopaedics. There remains a lack of information on the complex interplay between opioid utilization postoperatively, pain and patient satisfaction. This study aims to describe the relationship between opioid utilization, postoperative pain, and patient satisfaction following outpatient orthopaedic surgery in a multispecialty orthopaedic practice. As a part of an ongoing quality control project at our institution patients were instructed to monitor utilization of postoperative opioids. The results of a convenience sample of 139 patients representing a 53% response rate among eligible patients that completed the survey following outpatient orthopaedic surgery are reported. Among patients undergoing outpatient orthopaedic surgery, there was no clinically significant association between opioid utilization and patient satisfaction. This association appeared largely independent of the patient's actual pain. While lower pain scores were associated with increasing patient satisfaction, this appeared to be independent of opioid utilization. (Journal of Surgical Orthopaedic Advances 29(2):88-93, 2020).

Time to Dislocation Analysis of Lumbar Spine Fusion Following Total Hip Arthroplasty: Breaking Up a Happy Home.

BACKGROUND: Although a history of lumbar spine fusion (LSF) is associated with increased dislocation risk following total hip arthroplasty (THA), the effect of LSF following THA is not well described. This study sought to describe the dislocation-free survival experience of patients with THA undergoing LSF, compare this to similar patients not undergoing LSF, and assess factors associated with dislocation risk following LSF. METHODS: Center for Medicare Service billing data from 2005 to 2014 was analyzed utilizing the PearlDiver platform. Patients without evidence of hip instability, defined as no dislocation event within at least 6 months following THA, were identified and stratified by having subsequent LSF. Kaplan-Meier curves were used to describe dislocation-free survival of these groups and assess factors associated with dislocation. RESULTS: Among 17,223 patients without history of hip instability following THA, there was no spike in dislocations following LSF with patients having a persistent and stable rate of dislocation of 0.7% per year. This experience was of similar shape but increased hazard when compared to that of 863,182 patients not undergoing LSF who had a dislocation rate of 0.4% per year (P < .001). Dislocations were not strongly associated with gender, age, comorbidities, or fusion length. CONCLUSION: Patients without evidence of hip instability following THA subsequently undergoing LSF do not have a spike in dislocations in the perioperative period but do assume a persistently elevated risk of dislocation. Future research should identify factors responsible for this increased risk to determine whether they may be modifiable.

Thymidine kinase suicide gene-mediated ganciclovir ablation of autologous gene-modified rhesus hematopoiesis.

Despite the genotoxic complications encountered in clinical gene therapy trials for primary immunodeficiency diseases targeting hematopoietic cells with integrating vectors; this strategy holds promise for the cure of several monogenic blood, metabolic and neurodegenerative diseases. In this study, we asked whether the inclusion of a suicide gene in a standard retrovirus vector would allow elimination of vector-containing stem and progenitor cells and their progeny in vivo following transplantation, using our rhesus macaque transplantation model. Following stable engraftment with autologous CD34(+) cells transduced with a retrovirus vector encoding a highly sensitive modified Herpes simplex virus thymidine kinase SR39, the administration of the antiviral prodrug ganciclovir (GCV) was effective in completely eliminating vector-containing cells in all hematopoietic lineages in vivo. The sustained absence of vector-containing cells over time, without additional GCV administration, suggests that the ablation of TkSR39 GCV-sensitive cells occurred in the most primitive hematopoietic long-term repopulating stem or progenitor cell compartment. These results are a proof-of-concept that the inclusion of a suicide gene in integrating vectors, in addition to a therapeutic gene, can provide a mechanism for later elimination of vector-containing cells, thereby increasing the safety of gene transfer.

Transitioning a Practice to Robotic Total Knee Arthroplasty Is Correlated with Favorable Short-Term Clinical Outcomes-A Single Surgeon Experience.

BACKGROUND: This study sought to evaluate the patient experience and short-term clinical outcomes associated with the hospital stay of patients who underwent robotic arm-assisted total knee arthroplasty (TKA). These results were compared with a cohort of patients who underwent TKA without robotic assistance performed by the same surgeon prior to the introduction of this technology. MATERIALS AND METHODS: A cohort of consecutive patients undergoing primary TKA for the diagnosis of osteoarthritis by a single fellowship trained orthopaedic surgeon over a 39-month period was identified. Patients who underwent TKA during the year that this surgeon transitioned his entire knee arthroplasty practice to robotic assistance were excluded to eliminate selection bias and control for the learning curve. All patients received the same prosthesis and postoperative pain protocol. Patients that required intubation for failed spinal anesthetic were excluded. A final population of 492 TKAs was identified. Of these, 290 underwent TKA without robotic assistance and 202 underwent robotic arm-assisted TKA. Patient demographic characteristics and short-term clinical data were analyzed. RESULTS: Robotic arm-assisted TKA was associated with shorter length of stay (2.3 vs. 2.6 days, p < 0.001), a 50% reduction in morphine milligram equivalent utilization (from 214 to 103, p < 0.001), and a mean increase in procedure time of 9.3 minutes (p < 0.001). There was one superficial infection in the nonrobotic cohort and there were no deep postoperative infections in either cohort. There were no manipulations under anesthesia in the robotic cohort while there were six in the nonrobotic cohort. Additionally, there were no significant differences in emergency department visits, readmissions, or return to the operating room. CONCLUSION: This analysis corroborates existing literature suggesting that robotic arm-assisted TKA can be correlated with improved short-term clinical outcomes. This study reports on a single surgeon's experience with regard to analgesic requirements, length of stay, pain scores, and procedure time following a complete transition to robotic arm-assisted TKA. These results underscore the importance of continued evaluation of clinical outcomes as robotic arthroplasty technology continues to grow.

Distinguishing Periprosthetic Crystalline Arthropathy from Infection in Total Knee Arthroplasty: A Systematic Review.

Distinguishing periprosthetic crystalline arthropathy from periprosthetic joint infection (PJI) remains a diagnostic challenge as both symptom presentation and diagnostic tests overlap. Accurate differentiation is important as treatment plans vary significantly. We sought to systematically review all cases of total knee arthroplasty (TKA) periprosthetic crystalline arthropathy reported in the literature and summarize clinical, diagnostic, and operative findings in the context of guidelines for diagnosing PJI. The goal of this systematic review is to determine the amount of diagnostic overlap and to identify best practices for differentiating between these two diagnoses. MEDLINE and Google Scholar were searched to identify cases of crystalline arthropathy following TKA. Case reports were reviewed for patient characteristics, clinical symptoms, physical exam, laboratory results, and treatment outcomes. These findings were summarized across patients and dichotomized based on current thresholds for diagnosing PJI according to Musculoskeletal Infection Society criteria. Twenty-six articles were identified which included 42 cases of periprosthetic crystalline arthropathy (17 gout, 16 pseudogout, one both, and eight not specified). Of these cases, 25 presented over 1 year after their index arthroplasty and 15 had no prior history of crystalline arthropathy. Only six cases had a superimposed infection based on aspiration or intraoperative cultures. For cases without a culture-positive infection, several diagnostic tests overlap with PJI thresholds: 95% of patients had C-reactive protein greater than 1 mg/dL, 76% had an erythrocyte sedimentation rate greater than 30 mm/hour, 91% had a synovial white blood cell greater than 3,000 cells, and 76% had a synovial polymorphonuclear cells percent greater than 80%. Patients without co-infection were managed with non-steroidal anti-inflammatory drugs, colchicine, allopurinol, steroids, or a combination of these treatments and most had complete resolution of symptoms within 1 week. Commonly used markers of PJI fail to reliably distinguish periprosthetic crystalline arthropathy from infection. Though clinical judgement and consideration of the implications of delayed treatment for acute PJI remain paramount, in the setting of synovial crystals, surgeons may wish to consider this alternate etiology as the source of the patient's clinical symptoms.

Gout in primary total knee arthroplasty: Prevalent but not independently associated with complications.

BACKGROUND: Gout is a common synovial pathology, but its prevalence in patients undergoing total knee arthroplasty (TKA) and potential association with complications such as periprosthetic infection (PJI) and revision are unknown. METHODS: Medicare data from 2009 to 2013 was retrospectively reviewed using PearlDiver. All patients 65 years of age or older and undergoing primary TKA with at least 3 years of pre-TKA records were included. The prevalence of gout was based on ICD-9 codes. Univariable associations of gout with PJI and revision at 1 year were assessed using odds ratios with 95% confidence intrervals (C.I.). To control for potential confounding, patients with a history of gout were matched on age, gender, smoking history, and Elixhauser Comorbidity Index (ECI) to patients without gout and associations reassessed. RESULTS: The prevalence of gout in Medicare patients undergoing primary TKA was 5.7%. On univariable analysis, patients with a history of gout were more likely to develop PJI (O.R., 1.58; 95% C.I., 1.45-1.72) and undergo revision (O.R., 1.33; 95% C.I., 1.25-1.41) at 1 year. After matching for confounders, a history of gout was no longer associated with developing PJI (O.R., 0.98; 95% C.I., 0.90-1.06) or undergoing revision (O.R., 0.94; 95% C.I., 0.89-1.00) at 1 year. CONCLUSIONS: Gout is a relatively common pathology in patients undergoing TKA. While gout is associated with increased complications, this appears to be driven by confounding through its association with other medical comorbidities. Gout does not appear to be an independent risk factor for complications following TKA.

Opioid Naive Surgeons and Opioid-Tolerant Patients: Can Education Alter Prescribing Patterns to Total Knee Arthroplasty Patients?

Patterns of opioid overprescribing following arthroplasty likely developed given that poor pain control can diminish patient satisfaction, delay disposition, and lead to complications. Recently, interventions promoting responsible pain management have been described, however, most of the existing literature focuses on opioid naive patients. The aim of this study was to describe the effect of an educational intervention on opioid prescribing for opioid-tolerant patients undergoing primary total knee arthroplasty (TKA). As the start to a quality improvement initiative to reduce opioid overprescribing, a departmental grand rounds was conducted. Prescribing data, for the year before and after this intervention, were retrospectively collected for all opioid-tolerant patients undergoing primary TKA. Opioid prescribing data were standardized to mean morphine milligram equivalents (MME). Segmented time series regression was utilized to estimate the change in opioid prescribing associated with the intervention. A total of 508 opioid-tolerant patients underwent TKA at our institution during the study period. The intervention was associated with a statistically significant decrease of 468 mean MME (23%) from 2,062 to 1,594 (p = 0.005) in TKA patients. This study demonstrates that an educational intervention is associated with decreased opioid prescribing among opioid-tolerant TKA patients. While the effective management of these patients is challenging, surgeon education should be a key focus to optimizing their care.

Periprosthetic Hip Fractures Outside the Initial Postoperative Period: Does Time from Diagnosis to Surgery Matter?

BACKGROUND: Despite an increasing incidence and associated morbidity, the optimal timing for the surgical management of periprosthetic hip fractures remains unknown. This study sought to explore whether time to surgery was associated with medical or surgical complications. METHODS: A retrospective review of Medicare data from 2010 to 2014 was performed using PearlDiver. All patients with a periprosthetic hip fracture greater than 90 days from surgery and undergoing open reduction internal fixation (ORIF) or revision total hip arthroplasty (RTHA) were included. Time to surgery was measured from diagnosis and dichotomized at 48 hours. RESULTS: Of 342 patients undergoing ORIF, 269 (79%) had surgery within 48 hours. Of 255 patients undergoing RTHA, 142 (56%) had surgery within 48 hours. For ORIF, surgery more than 48 hours after diagnosis was associated with an increased rate of 30-day deep vein thrombosis or pulmonary embolism (15% vs 7%, P = .03), which remained after adjustment (odds ratio [OR]: 2.71, 95% confidence interval [CI]: 1.11-6.45). A similar association was seen for RTHA (12% vs 6%, P = .09 and OR: 2.61, 95% CI 1.01-7.24). For RTHA, surgery more than 48 hours after diagnosis was associated with an increased rate of 90-day periprosthetic joint infection (12% vs 4%, P = .007), which remained after adjustment (OR: 3.86, 95% CI: 1.36-12.72). A similar but not significant association was seen for ORIF (7% vs 3%, P = .18 and OR: 2.65, 95% CI: 0.73-8.91). CONCLUSIONS: Among Medicare patients with a periprosthetic hip fracture, time to surgery greater than 48 hours was associated with increased medical and surgical complications.