The Fate of the Inconclusive Periprosthetic Joint Infection Workup and Reliability of Data Points.

In 2018, periprosthetic joint infection (PJI) criteria were revised to include a new category labeled "inconclusive." The purpose of this study was to characterize and describe the fate of the inconclusive PJI workup and to analyze preoperative factors associated with outcomes. We reviewed all PJI workups at our institution during a 3-year period (426 patients). Patients were labeled "infected," "not infected," or "inconclusive" according to 2018 PJI preoperative criteria. In addition to standard diagnostic variables, the presence or absence of clinical elements that increase the pretest probability of infection were collected. Patients with any missing preoperative diagnostic test results and those with clinical follow-up less than 30 days were excluded. Logistic regression was used to identify the factors associated with infection. Two hundred ninety-six workups remained after exclusion criteria were applied, consisting of 66 (22.2%) with a preoperative score of 6 or greater defined as infected, 52 (17.6%) inconclusive (score 2-5), and 178 (60.1%) not infected (score 0-1). Postoperative re-scoring of the inconclusive group based on intraoperative findings as per the 2018 criteria identified 6 of 52 (11.5%) as infected, 12 (23.1%) inconclusive, and 34 (65.4%) not infected. Among those preoperatively scored as inconclusive, variables statistically correlated with the presence of infection included history of PJI, factors that increase skin barrier penetration (eg, psoriasis and venous stasis), and presence of comorbidities predisposing to infection. For patients labeled inconclusive, clinical elements of the pretest probability for infection (eg, history of prior PJI) were as reliable as any diagnostic test, including alpha-defensin, in the diagnosis of PJI. [Orthopedics. 2023;46(5):e291-e297.].

What are the 2-year survivorship outcomes of custom hemipelvis reconstruction after hemipelvectomy and revision arthroplasty? The evolution of a custom ilium "monoflange".

BACKGROUND: Innovations in machined and three-dimensionally (3D) printed implant technology have allowed for customized complex pelvic reconstructions. We sought to determine the survivorship of custom hemipelvis reconstruction using ilium-only fixation at a minimum 2-year follow-up, their modes of failure, and the postoperative complications resulting from the procedure. METHODS: A retrospective review identified 12 consecutive patients treated with custom hemipelvis reconstruction. Indications for surgery were bone tumor requiring internal hemipelvectomy (four patients) or multiply revised, failed hip arthroplasty with massive bone loss (eight patients). All patients had a minimum of 2-year follow-up with a mean of 60.5 months. Kaplan-Meier survivorship analysis was determined for all patients. Postoperative complications and reoperations were categorized for all patients. RESULTS: At a mean of 60.5 months, 11 of 12 patients had retained their custom implant (92% survivorship). One implant was removed as a result of an acute periprosthetic joint infection (PJI). There were no cases of aseptic loosening. Seven of 12 patients required reoperation (three PJI; two dislocations; two superficial wound complications), with five patients going on to reoperation-free survival. CONCLUSIONS: Custom hemipelvis reconstruction utilizing an ilium monoflange provides durable short-term fixation at a minimum 2-year follow-up. Reoperation for infection and dislocation is common.

Abnormal Spinopelvic Motion and Spine Deformity are Associated With Native Femoral Retroversion in the Setting of Total Hip Arthroplasty.

Background: The effect of spinopelvic pathology on femoral version is unclear. This study investigated variability in native femoral anteversion in patients undergoing total hip arthroplasty (THA) and its relationship to the patient's underlying spinopelvic pattern. Methods: A retrospective chart review was performed to include in the study all patients undergoing robot-assisted THA over a 3-year period. Native femoral version was measured for each patient using a preoperative computed tomography scan and categorized as excessive, normal, or retroverted. Additionally, a subset analysis was performed for all patients with sit-to-stand dynamic pelvic radiographs available, and cases were classified by spinopelvic pattern. Results: A total of 119 patients were included in the study with a mean age of 68.6 years; 61 (51%) were female. The median femoral anteversion for the entire study group was 6.0° (-32° to 40°, interquartile range 13.5°). Eleven patients (9.2%) had excessive femoral anteversion, 54 of the 119 (45.4%) had normal femoral version, and 54 of the 119 (45.4%) had native retroversion. Forty-two patients (35.3%) had sit-to-stand radiographs available and were subclassified by femoral version type and spinopelvic parameters. Welch's analysis of variance demonstrated a significant difference in femoral version among spinopelvic patterns (F = 7.826, P = .003), with Games-Howell post hoc analysis showing increased retroversion in deformity-stiff patients compared to deformity-normal mobility patients (P = .003). Conclusions: This study demonstrates that native femoral retroversion is present in a significant number of patients undergoing THA and is more common in patients with stiff spine deformities. Based on this observation, currently available spinopelvic classification systems should be modified to account for native femoral version.

Robotic-Assisted Total Knee Arthroplasty Allows for Trainee Involvement and Teaching Without Lengthening Operative Time.

BACKGROUND: Robot-assisted total knee arthroplasty (RA-TKA) is more accurate than mechanical total knee arthroplasty (M-TKA) and can provide real-time feedback about alignment and soft-tissue balancing that may be helpful in trainee education. However, both robotic-assist and trainee involvement potentially increase the surgical time. This study sought to evaluate whether RA-TKA procedures were longer than M-TKA procedures and whether trainee participation added additional surgical time. METHODS: This retrospective cohort study reviewed 220 consecutive primary TKAs (110 M-TKA and 110 RA-TKA) performed by an orthopedic trainee under supervision or performed by the consultant surgeon with an assistant present. For M-TKAs, a measured resection technique was used. For all RA-TKAs, the MAKO robotic system (Stryker, USA) was used. Tourniquet time was measured from inflation immediately prior to skin incision to deflation after placement of the final polyethylene insert. Procedures performed by a consulting surgeon with a surgical assist were used as controls for procedures performed by the trainee. In trainee-conducted procedures, the trainee is responsible for performing all critical aspects of the procedure while the consulting surgeon provides supervision and acts as first assist. RESULTS: 103 M-TKA and 96 RA-TKA were included. Tourniquet time was significantly longer for RA-TKAs vs M-TKAs (100 vs 89 minutes, P < .0001). However, there were no significant differences in tourniquet times between surgery performed by a trainee vs the consulting surgeon with surgical assist for either M-TKA (P = .3452) or RA-TKA (P = .6724). CONCLUSIONS: While RA-TKA takes longer, orthopedic trainees do not add additional time. Trainees at all stages of postgraduate learning can be educated in the use of robotic technology and potentially benefit from real-time feedback without further compromising surgical efficiency or increasing patient risk.

Cost-effectiveness of Single vs Double Debridement and Implant Retention for Acute Periprosthetic Joint Infections in Total Knee Arthroplasty: A Markov Model.

BACKGROUND: Periprosthetic joint infection (PJI) is a common cause of revision total knee surgery. Although debridement and implant retention (DAIR) has lower success rates in the chronic setting, it is an accepted treatment of acute PJI, whether postoperatively or with late hematogenous seeding. There are two broad DAIR strategies: single debridement and planned double debridement. The purpose of this study is to evaluate the cost-effectiveness of single vs double DAIR for acute PJI in total knee arthroplasty. METHODS: A decision tree using single or double DAIR as the treatment strategy for acute PJI was constructed. Quality-adjusted life years and costs associated with the two treatment arms were calculated. Treatment success rates, failure rates, and mortality rates were derived from the literature. Medical costs were derived from both the literature and Medicare data. A cost-effectiveness plane was constructed from multiple Monte Carlo trials. A sensitivity analysis identified parameters most influencing the optimal strategy decision. RESULTS: Double DAIR was the optimal treatment strategy both in terms of the health utility state (82% of trials) and medical cost (97% of trials). Strategy tables demonstrated that as long as the success rate of double debridement is 10% or greater than the success rate of a single debridement, the two-stage protocol is cost-effective. CONCLUSIONS: A double DAIR protocol is more cost-effective than single DAIR from a societal perspective.

A Contemporary Classification System of Femoral Bone Loss in Revision Total Hip Arthroplasty.

BACKGROUND: Current femoral bone loss classification systems in revision total hip arthroplasty were created at a time when the predominant reconstructive methods used cylindrical porous-coated cobalt-chrome stems. As these stems have largely been replaced by fluted-tapered titanium stems, the ability of these classification systems to help guide implant selection is limited. The purpose of this study was to describe a novel classification system based on contemporary reconstructive techniques. METHODS: We reviewed the charts of all patients who underwent femoral component revision at our institution from 2007 through 2019. Preoperative images were reviewed, and FBL was rated according to the Paprosky classification and compared to ratings using our institution's NCS. Rates of reoperation at the time of most recent follow-up were determined and compared. RESULTS: Four-hundred and forty-two femoral revisions in 330 patients with a mean follow-up duration of 2.7 years were identified. Femoral type according to Paprosky and NCS were Paprosky I (36, 8.1%), II (61, 13.8%), IIIA (180, 40.7%), IIIB (116, 26.2%), and IV (49 11.1%) and NCS 1 (35, 7.9%), 2 (364, 82.4%), 3 (8, 1.8%), 4 (27, 6.1%), and 5 (8, 1.8%). Of the 353 nonstaged rTHAs, there were 42 cases requiring unplanned reoperation (11.9%), including infection (18, 5.1%), instability (10, 2.8%), femoral loosening (5, 1.4%), and various other causes (9, 2.5%). The NCS was more predictive of reoperation than the Paprosky classification (Fisher's exact test, P = .008 vs P = ns, respectively). CONCLUSION: We present a novel femoral classification system that can help guide contemporary implant selection.

What Is The Value Of A Star When Choosing A Provider For Total Joint Replacement? A Discrete Choice Experiment.

The past decade witnessed a rapid rise in the public reporting of surgeon- and hospital-specific quality-of-care measures. However, patients' interpretations of star ratings and their importance relative to other considerations (for example, cost, distance traveled) are poorly understood. We conducted a discrete choice experiment in an outpatient setting (an academic joint arthroplasty practice) to study trade-offs that patients are willing to make in choosing a provider for a hypothetical total joint arthroplasty. Two hundred consecutive new patients presenting for hip or knee pain in 2018 were included. The average patient was willing to pay $2,607 and $3,152 extra for an additional hospital or physician star, respectively, and an extra $11.45 to not travel an extra mile for arthroplasty care. History of prior surgery and prior experience with rating systems reduced the relative value of an incremental star by $539.25 and $934.50, respectively. Patients appear willing to accept significantly higher copayments for higher quality of care, and surgeon quality seems relatively more important than hospital quality. Further study is needed to understand the value and trust patients place in publicly reported hospital and surgeon quality ratings.

The July Effect for Total Joint Arthroplasty Procedures.

The "July effect" refers to the assumed increased risk of complications during the months when medical school graduates transition to residency programs. The actual existence of a July effect is controversial. With this study, the authors sought to determine whether evidence exists for the presence of a July effect among total joint arthroplasty (TJA) procedures. The 2013 and 2014 Nationwide Readmission Databases were combined and all index primary and revision arthroplasty procedures were identified, and then patients from December were excluded. Thirty-day readmission rates, time to readmission, and readmission costs were analyzed by index procedure month and index procedure type. A total of 1,193,034 procedures (index primary: n=1,107,657; revision arthroplasty: n=85,377) were identified. Among all procedure types, 46,674 (3.9%) 30-day readmissions were observed. Among all procedures, an index procedure with a discharge in July resulted in the highest monthly readmission rate of the year (4.2%), which was significantly higher than the mean annual readmission rate (P<.0001). This effect was most pronounced for primary total knee arthroplasty (3.9% vs 3.6%, P<.0001). When stratifying results into teaching vs nonteaching hospitals, the highest readmission rate occurred if the index procedure occurred at a nonteaching hospital in July (4.5%, P<.0001). These data provide evidence that a July effect appears to exist for TJA procedures and is most pronounced at nonteaching institutions. Based on published mean readmission costs, the total annualized cost variation attributable to the higher readmission rate for primary TJA procedures in July is approximately $18.6 million. [Orthopedics. 2020;43(6):e543-e548.].

Hip Disarticulation for Periprosthetic Joint Infection: Frequency, Outcome, and Risk Factors.

BACKGROUND: Currently, the largest available series of hip disarticulation (HD) procedures performed for periprosthetic joint infection (PJI) includes only 6 patients. Given the lack of data on this dreadful outcome, we sought to determine the frequency of and risk factors for HD performed for a primary diagnosis of PJI. METHODS: The National Inpatient Sample from 1998 to 2016 was used to estimate the annual incidences of HD associated with PJI, elective primary total joint arthroplasty (control group 1), and other surgical procedures associated with PJI (control group 2) using National Inpatient Sample trend weights. RESULTS: One-hundred forty-eight HDs for PJI, 2,378,313 primary total joint arthroplasty controls, and 51,580 PJI controls were identified. Median length-of-stay (11 days), proportion of patients with ≥5 comorbidities (22.8%), and median hospital costs ($25,895.60) were all greater for patients with HD compared with both control groups. The weighted frequency of HD hospitalizations increased by 366%, whereas the frequency of cases in control groups 1 and 2 increased by 93% and 310%, respectively, during the same timeframe. Upon multivariable logistic regression, age <65 years without private insurance (reference group: age ≥65 years without private insurance, odds ratio [OR]: 1.55; 95% confidence interval [CI]: 1.08-2.24), diabetes with chronic complications (OR: 1.91; 95% CI: 1.12-3.26), and peripheral vascular disease (OR: 2.59; 95% CI: 1.49-4.48) were significantly associated with increased risk of HD among all patients with PJI. CONCLUSION: While the overall frequency of lower extremity amputations may be decreasing, our study documents an alarming increase in the frequency of HD for PJI during the study period. Patients under age 65 years without private insurance were at significantly higher risk of HD among patients with PJI.

Can a Convolutional Neural Network Classify Knee Osteoarthritis on Plain Radiographs as Accurately as Fellowship-Trained Knee Arthroplasty Surgeons?

BACKGROUND: Osteoarthritis (OA) is the leading cause of disability among adults in the United States. As the diagnosis is based on the accurate interpretation of knee radiographs, use of a convolutional neural network (CNN) to grade OA severity has the potential to significantly reduce variability. METHODS: Knee radiographs from consecutive patients presenting to a large academic arthroplasty practice were obtained retrospectively. These images were rated by 4 fellowship-trained knee arthroplasty surgeons using the International Knee Documentation Committee (IKDC) scoring system. The intraclass correlation coefficient (ICC) for surgeons alone and surgeons with a CNN that was trained using 4755 separate images were compared. RESULTS: Two hundred eighty-eight posteroanterior flexion knee radiographs (576 knees) were reviewed; 131 knees were removed due to poor quality or prior TKA. Each remaining knee was rated by 4 blinded surgeons for a total of 1780 human knee ratings. The ICC among the 4 surgeons for all possible IKDC grades was 0.703 (95% confidence interval [CI] 0.667-0.737). The ICC for the 4 surgeons and the trained CNN was 0.685 (95% CI 0.65-0.719). For IKDC D vs any other rating, the ICC of the 4 surgeons was 0.713 (95% CI 0.678-0.746), and the ICC of 4 surgeons and CNN was 0.697 (95% CI 0.663-0.73). CONCLUSIONS: A CNN can identify and classify knee OA as accurately as a fellowship-trained arthroplasty surgeon. This technology has the potential to reduce variability in the diagnosis and treatment of knee OA.

Why Do Patients Stay Longer Than Three Nights Following Hip and Knee Arthroplasty?

BACKGROUND: Prolonged length of stay (PLOS) is frequently cited by secondary data studies as an adverse outcome following hip and knee arthroplasty. Although perhaps indisputable that PLOS increases the cost of hospitalization, it is unknown whether it is an appropriate measure of the quality of an arthroplasty procedure. METHODS: We searched our institution's database for all hip and knee arthroplasty procedures over a 5-year period using MS-DRG (Medicare Severity-Diagnosis Related Group) 469 and 470. Cases with greater than 3 night stays were identified. Charts were manually reviewed by 2 independent reviewers to identify the primary reason for PLOS, and the need for 30-day readmission or reoperation. RESULTS: Of a total 4347 hip and knee arthroplasty cases, 218 (5.0%) were identified with LOS greater than 3 nights. The majority of prolonged stays were due to exclusively medical reasons (81 cases: 37.2%; 95% confidence interval [CI] 31.0-43.7). The second most common cause was inpatient days prior to the arthroplasty procedure (45 cases: 20.6%; 95% CI 15.8-26.5). Orthopedic reasons for PLOS were significantly less common than medical reasons (36 cases: 16.5%; 95% CI 12.2-22.0, P < .0001), most often due to failure to meet therapy goals. Neither readmission (31 cases: 14.2%) nor reoperation (10 cases: 4.6%) was associated with an underlying reason for PLOS. CONCLUSION: When evaluating LOS as a measure of quality of an arthroplasty procedure, readers of secondary "big data" studies should be aware that there are significant limitations to its utility. Even after controlling for potential confounders, we found that PLOS does not necessarily reflect an adverse outcome.

Is There an Optimal Cutoff for Aspiration Fluid Volume in the Diagnosis of Periprosthetic Joint Infection?

BACKGROUND: The diagnosis of periprosthetic joint infection is often challenging in the setting of low aspiration volumes, or in the presence of infection with a slow-growing organism. We sought to determine if an optimal threshold of aspiration fluid volume exists when cultures from the preoperative aspiration are compared to intraoperative cultures. METHODS: All revision total hip and knee arthroplasty procedures over 5 years at our institution were reviewed. Cases were excluded if they underwent joint lavage during aspiration, had an antibiotic spacer in place, were suspected of adverse local tissue reaction to metal debris, did not have an accurate aspiration volume recorded, or if there were no aspiration or operative cultures available. Receiver operating characteristic curves were used to evaluate aspiration volume for identifying cases with identical aspiration and culture results. RESULTS: A total of 857 revision cases were reviewed, among which 294 met inclusion criteria. There were 45 cases (15.3%) with discordant aspiration and operative cultures. The mean aspiration volume for identical cases was significantly higher than for discordant cases (19.1 vs 10.2 mL, P = .02). The proportion of slow-growing organisms was significantly greater among discordant compared to identical operative cultures (52.4% for discordant cases vs 8.2% for identical cases, P < .001). The optimal cutoff value for predicting identical cultures was 3.5 mL for typical organisms and 12.5 mL for slow-growing organisms. CONCLUSION: Aspiration cultures are more likely to correlate with intraoperative cultures with higher aspiration volumes, and the optimal aspiration volume is higher for slow-growing organisms.

Long-Term Trends in Postoperative Opioid Prescribing, 1994 to 2014.

Opioids are routinely prescribed to manage acute postoperative pain, but changes in postoperative opioid prescribing associated with the marketing of long-acting opioids such as OxyContin have not been described in the surgical cohort. Methods: Using a large commercial claims data set, we studied postoperative opioid prescribing after selected common surgical procedures between 1994 and 2014. For each procedure and year, we calculated the mean postoperative morphine milligram equivalents (MME) filled on the index prescription and assessed the proportion of patients who filled a high-dose prescription (≥350 MME). We reported changes in postoperative opioid prescribing over time and identified predictors of filling a high-dose postoperative opioid prescription. Results: We identified 1,321,264 adult patients undergoing selected common surgical procedures between 1994 and 2014, of whom 80.3% filled a postoperative opioid prescription. One in five surgery patients filled a high-dose postoperative opioid prescription. Between 1994 and 2014, the mean MME filled increased by 145%, 84%, and 85% for lumbar laminectomy/laminotomy, total knee arthroplasty, and total hip arthroplasty, respectively. The procedures most likely to be associated with a high-dose opioid fill were all orthopaedic procedures (AOR 5.20 to 7.55, P < 0.001 for all). Patients whose postoperative opioid prescription included a long-acting formulation had the highest odds of filling a prescription that exceeded 350 MME (AOR 32.01, 95% CI, 30.23-33.90). Discussion: After the US introduction of long-acting opioids such as OxyContin, postoperative opioid prescribing in commercially insured patients increased in parallel with broader US opioid-prescribing trends, most notably among patients undergoing orthopaedic surgical procedures. The increase in the mean annual MME filled starting in the late 1990s was driven in part by the higher proportion of long-acting opioid formulations on the index postoperative opioid prescription filled by orthopaedic surgery patients.

Aversion to Total Joint Arthroplasty: Functional Scores Predict Patient Preferences.

Many patients who may benefit from total hip arthroplasty and total knee arthroplasty prefer to avoid surgery. Reasons for avoidance may include, but are not limited to, experience or dissatisfaction with prior treatment, living status, and symptom severity. Taking these variables into account, the authors sought to determine whether preoperatively collected functional scores would predict an aversion to total joint arthroplasty. A prospective cross-sectional survey was administered to consecutive patients during a 5-month period at the initial consultation for osteoarthritis of the hip or knee. Patient demographics, Hip disability and Osteoarthritis Outcome Score (HOOS), Knee injury and Osteoarthritis Outcome Score (KOOS), Veterans RAND 12-Item Health Survey (VR-12) score, radiographic findings, and preference for or against surgical treatment for osteoarthritis were collected. Logistic regression was performed to determine factors associated with aversion to total joint arthroplasty, and receiver operating characteristic curves were used to determine an appropriate functional score cutoff associated with aversion to surgery. Twenty-two of 103 total patients (21.4%) were averse to surgery. The proportion of patients who underwent surgery was significantly smaller for those averse compared with those not averse to surgery (4.6% vs 23.5%, P<.05). Baseline characteristics, including age, radiographic scores, satisfaction with prior treatment, work status, education, living status, and VR-12 scores were similar between the groups. Functional scores were significantly higher for averse patients (KOOS, 66.6 vs 50.6, P<.001; HOOS, 73.2 vs 62.2, P<.05). Univariate logistic regression revealed a significant association between functional scores and aversion. Optimal cutoff values for all patients overall were 57.1 and 58.9, with an area under the curve of 0.73 and 0.68, for KOOS and HOOS, respectively. Initial aversion was a strong predictor of the ultimate method of treatment chosen. When controlling for other clinically important baseline characteristics, prospectively collected functional scores may be useful in predicting surgical aversion. [Orthopedics. 2020;43(3):147-153.].

Frequency, Cost, and Clinical Significance of Incidental Findings on Preoperative Planning Images for Computer-Assisted Total Joint Arthroplasty.

BACKGROUND: The frequency of incidental findings with computer-assisted total joint arthroplasty (CA TJA) preoperative imaging and their clinical significance are currently unknown. METHODS: We reviewed 573 patients who underwent primary CA TJA requiring planning imaging. Incidental findings were defined as reported findings excluding those related to the planned arthroplasty. Secondary outcomes were additional tests or a delay in surgery. Associated charges were obtained from our institution's website. Charge and incidence data were combined with TJA volumes obtained from the 2016 National Inpatient Sample to model costs to the healthcare system. RESULTS: Overall, 262 patients (45.7%) had at least 1 incidental finding, 144 patients (25.1%) had 2, and 65 (11.3%) had 3. The most common finding types were musculoskeletal (MSK, 67.7%), digestive (19.5%), cardiovascular (4.9%), and reproductive (4.7%). Also, 9.3% of patients had at least 1 non-MSK incidental finding. Both MSK and non-MSK incidental findings were more common with total hip arthroplasty compared to total knee arthroplasty (67.9% vs 42.2%, P < .0001, and 15.4% vs 8.3%, P < .05, respectively). Further testing was required in 6 cases (1.0%); 1 case required delay in surgery (0.2%). Using the 2016 volume of TJA procedures and assuming a 10%, 15%, and 25%, utilization rate of image-based CA TJA, the annual cost of additional testing was $2.7 million (95% confidence interval, $1.1-$6.3 million), $4.1 million ($1.6-$9.5 million), and $6.9 million (95% confidence interval, $2.7-$15.8 million), respectively. CONCLUSION: Incidental findings are relatively common on planning images. Stakeholders should be aware of the hidden costs of incidental findings given the increasing popularity of image-based CA TJA.

A novel technique for retrieval of a broken biopsy needle.

A broken needle is a rare complication of bone biopsy. We describe an easily applied technique of retrieval of a retained biopsy needle fragment using a cannulated drill typically used for internal fixation of femoral neck fractures. This approach allows for removal under moderate conscious sedation and can be performed by a radiologist using fluoroscopic or CT-fluoroscopic guidance in the radiology suite.