Hip joint center lateralization minimally affects the biomechanics of patient-specific flanged acetabular components: A computational model

Patient-specific flanged acetabular components are utilized to treat failed total hip arthroplasties with large acetabular defects. Previous clinical studies from our institution showed that these implants tend to lateralize the acetabular center of rotation. However, the clinical impact of lateralization on implant survivorship is debated. Our goal was to develop a finite element model to quantify how lateralization of the native hip center affects periprosthetic strain and implant-bone micromotion distributions in a static level gait loading condition. To build the model, we computationally created a superomedial acetabular defect in a computed tomography 3D reconstruction of a native pelvis and designed a flanged acetabular implant to address this simulated bone defect. We modeled two implants, one with ~1 cm and a second with ~2 cm of hip center lateralization. We applied the maximum hip contact force and corresponding abductor force observed during level gait. The resulting strains were compared to bone fatigue strength (0.3% strain) and the micromotions were compared to the threshold for bone ingrowth (20 µm). Overall, the model demonstrated that the additional lateralization only slightly increased the area of bone at risk of failure and decreased the areas compatible with bone ingrowth. This computational study of patient-specific acetabular implants establishes the utility of our modeling approach. Further refinement will yield a model that can explore a multitude of variables and could be used to develop a biomechanically-based acetabular bone loss classification system to guide the development of patient-specific implants in the treatment of large acetabular bone defects.

Telemedicine in Arthroplasty Patients: Which Factors Are Associated With High Satisfaction?

Background

During the initial coronavirus pandemic lockdown period, remote hip and knee arthroplasty care was heavily employed out of necessity. However, data on patient satisfaction with telemedicine specific to hip and knee arthroplasty patients remains unknown.

Methods

All patients who had a telemedicine visit in the hip and knee arthroplasty department and completed a telemedicine satisfaction survey at a specialty hospital from April 1, 2020, to December 31, 2020, were identified. Patient satisfaction with telemedicine, gauged through a series of questions, were analyzed and evaluated over time. Independent factors associated with high satisfaction, defined as the "Top Box" response to the survey question "Likelihood of your recommending our video visit service to others," were identified.

Results

Overall, 29,003 patients who had an in-person or telemedicine visit in the hip and knee arthroplasty department during the study period were identified. During the initial coronavirus pandemic lockdown period, defined as April 1, 2020-May 31, 2020, rate of overall telemedicine utilization was approximately 84%. After the initial lockdown period, the rate of overall telemedicine utilization was approximately 8% of all visits per month. Average satisfaction scores for a series of 14 questions were consistently above 4.5 out of 5. Multivariable regression revealed younger age, particularly 18-64 years old, to be the only independent factor associated with high satisfaction with telemedicine. The rate of high satisfaction remained statistically similar throughout the study period (P > .05).

Conclusions

Patient satisfaction with telemedicine was consistently high in various domains and remained high throughout the study period, regardless of loosened pandemic restrictions. This technology will most likely continue to be utilized, but perhaps it should be targeted at patients younger than 65 years of age.

Does Approach Matter in Robotic-Assisted Total Hip Arthroplasty? A Comparison of Early Reoperations Between Direct Anterior and Postero-Lateral Approach

BACKGROUND

There is no consensus on whether direct anterior approach (DAA) or postero-lateral approach (PLA) total hip arthroplasty (THA) confers a lower risk of postoperative complications. Robotic assistance in THA results in a more consistently accurate component position compared to manual THA. The objective of this study was to compare rates of dislocation, reoperation, revision, and patient-reported outcome measures between patients undergoing DAA and PLA robotic-assisted primary THA.

METHODS

We identified 2,040 consecutive robotic-assisted primary THAs performed for primary osteoarthritis, using DAA (n = 497) or PLA (n = 1,542) between 2017 and 2020. The mean follow-up was 18 months. Kaplan-Meier analysis estimated survivorship free of dislocation, reoperation, and revision. Achievement of patient acceptable symptom state and minimum clinically important difference were used to compare changes in the Hip Disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS JR) and Visual Analog Scale.

RESULTS

Dislocation was rare in this series (14 in 2,040, 0.7%), including 1 of 497 (0.2%) in the DAA cohort and 13 of 1,542 (0.8%) in the PLA cohort (P = .210). There was no difference in 2-year reoperation-free survivorship (97.8 versus 98.6%, P = .59) or revision-free survivorship (98.8 versus 99.0%, P = .87) at any time point. After controlling for age, sex, and body mass index, there was no difference in dislocation, reoperation, or revision. At 6-week follow-up, after controlling for age, sex, and body mass index, patients in the DAA cohort had higher odds of achieving HOOS JR minimum clinically important difference (odds ratio = 2.01, P = .012) and HOOS JR patient acceptable symptom state (odds ratio = 1.72, P = .028). There were no differences in patient-reported outcome measures by 3 months.

CONCLUSIONS

For robotic-assisted primary THA, DAA may confer enhanced early (<6 weeks) functional recovery compared to the PLA, but there was no significant difference in postoperative dislocation, reoperation, or revision rates.

The John N. Insall Award: Does Melatonin Improve Subjective Sleep Quality After Total Knee Arthroplasty? A Randomized, Placebo-Controlled Trial

BACKGROUND

Sleep disturbance is a common problem following total knee arthroplasty (TKA). The objective of this study was to determine if exogenous melatonin improves sleep quality following primary TKA.

METHODS

A randomized, double-blind, placebo-controlled trial was conducted. A total of 172 patients undergoing unilateral TKA for primary knee osteoarthritis were randomized to receive either 5 mg melatonin (n = 86) or 125 mg vitamin C placebo (n = 86) nightly for 6 weeks. The primary outcome was the Pittsburgh Sleep Quality Index (PSQI) at 6 weeks and 90 days postoperatively. Secondary outcomes included 6-week and 90-day patient-reported outcome measures (PROMs), morphine milligram equivalents prescribed, medication compliance, adverse events, and 90-day readmissions.

RESULTS

Mean PSQI scores worsened at 6 weeks before returning to the preoperative baseline at 90 days in both groups. There were no differences in PSQI scores between melatonin and placebo groups at 6 weeks (10.2 ± 4.2 versus 10.5 ± 4.4, P = .66) or 90 days (8.1 ± 4.1 versus 7.5 ± 4.0, P = .43). Melatonin did not improve the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, Lower Extremity Activity Scale, Visual Analog Scale for pain, or Veterans Rand 12 Physical Component Score or Mental Component Score at 6 weeks or 90 days. Poor sleep quality was associated with worse PROMs at 6 weeks and 90 days on univariate and multivariable analyses, but melatonin did not modify these associations. There were no differences in morphine milligram equivalents prescribed, medication compliances, adverse events, or 90-day readmissions between both groups.

CONCLUSIONS

Exogenous melatonin did not improve subjective sleep quality or PROMs at 6 weeks or 90 days following TKA. Poor sleep quality was associated with worse patient-reported function and pain. Our results do not support the routine use of melatonin after TKA.

Survivorship and Clinical Outcomes of Primary Total Knee Arthroplasty Performed in Patients 35 Years of Age and Younger

BACKGROUND

Total knee arthroplasties (TKAs) for patients aged ≤35 years are rare but necessary for patients who have diseases such as juvenile idiopathic arthritis, osteonecrosis, osteoarthritis, and rheumatoid arthritis. Few studies have examined the 10-year and 20-year survivorship and clinical outcomes of TKAs for young patients.

METHODS

A retrospective registry review identified 185 TKAs in 119 patients aged ≤ 35 years performed between 1985 and 2010 at a single institution. The primary outcome was implant survivorship free of revision. Patient-reported outcomes were assessed at 2 time points: 2011 to 2012 and 2018 to 2019. The average age was 26 years (range, 12 to 35). Mean follow-up was 17 years (range, 8 to 33).

RESULTS

Survivorship decreased from 84% (95% confidence interval [CI]: 79 to 90) at 5 years to 70% (95% CI: 64 to 77) at 10 years and to 37% (95% CI: 29 to 45) at 20 years. The most common reasons for revision were aseptic loosening (6%) and infection (4%). Risk factors for revision included increasing age at time of surgery (Hazards Ratio [HR] 1.3, P = .01) and use of constrained (HR 1.7, P = .05) or hinged prostheses (HR 4.3, P = .02). There were 86% of patients reporting that their surgery resulted in "a great improvement" or better.

CONCLUSION

Survivorship of TKAs in young patients is less favorable than expected. However, for the patients who responded to our surveys, TKA demonstrated substantial pain relief and improvement in function at 17-year follow-up. Revision risk increased with older age and higher levels of constraint.

2023 American College of Rheumatology and American Association of Hip and Knee Surgeons Clinical Practice Guideline for the Optimal Timing of Elective Hip or Knee Arthroplasty for Patients With Symptomatic Moderate-to-Severe Osteoarthritis or Advanced Symptomatic Osteonecrosis With Secondary Arthritis for Whom Nonoperative Therapy Is Ineffective

OBJECTIVE

To develop evidence-based consensus recommendations for the optimal timing of hip and knee arthroplasty to improve patient-important outcomes including, but not limited to, pain, function, infection, hospitalization, and death at 1 year for patients with symptomatic and radiographic moderate-to-severe osteoarthritis or advanced symptomatic osteonecrosis with secondary arthritis of the hip or knee who have previously attempted nonoperative therapy, and for whom nonoperative therapy was ineffective, and who have chosen to undergo elective hip or knee arthroplasty (collectively referred to as TJA).

METHODS

We developed 13 clinically relevant population, intervention, comparator, outcomes (PICO) questions. After a systematic literature review, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to rate the quality of evidence (high, moderate, low, or very low), and evidence tables were created. A Voting Panel, including 13 physicians and patients, discussed the PICO questions until consensus was achieved on the direction (for/against) and strength (strong/conditional) of the recommendations.

RESULTS

The panel conditionally recommended against delaying TJA to pursue additional nonoperative treatment including physical therapy, nonsteroidal antiinflammatory drugs, ambulatory aids, and intraarticular injections. It conditionally recommended delaying TJA for nicotine reduction or cessation. The panel conditionally recommended delay for better glycemic control for patients who have diabetes mellitus, although no specific measure or level was identified. There was consensus that obesity by itself was not a reason for delay, but that weight loss should be strongly encouraged, and the increase in operative risk should be discussed. The panel conditionally recommended against delay in patients who have severe deformity or bone loss, or in patients who have a neuropathic joint. Evidence for all recommendations was graded as low or very low quality.

CONCLUSION

This guideline provides evidence-based recommendations regarding the optimal timing of TJA in patients who have symptomatic and radiographic moderate-to-severe osteoarthritis or advanced symptomatic osteonecrosis with secondary arthritis for whom nonoperative therapy was ineffective to improve patient-important outcomes, including pain, function, infection, hospitalization, and death at 1 year. We acknowledge that the evidence is of low quality primarily due to indirectness and hope future research will allow for further refinement of the recommendations.

Correcting Hip Dysplasia in Young Adults: Intraoperative Navigation and Outcomes

Developmental dysplasia of the hip (DDH) often leads to characteristic acetabular dysplasia and typical femoral anomalies. There are numerous treatments for skeletally mature patients with DDH including hip arthroscopy, pelvic and femoral osteotomies, as well as total hip arthroplasty. Before proceeding to an arthroplasty procedure, it can be helpful to obtain an opinion of a hip preservation specialist to ascertain if alternative surgical treatments could contribute to the patient's care. In general, the use of robotic navigation has been associated with a higher proportion of cups placed in the Lewinnek safe zone, larger improvements in Harris Hip Scores, and no difference in overall complication rates in comparison to manual total hip arthroplasty. The use of robotic navigation allows for both 2-dimensional and 3-dimensional preoperative templating, enabling the surgeon to plan the position of the construct such that it achieves maximum bony purchase and hip stability. In complex DDH cases, surgeons can work with a biomechanics department to complete a fit check assessment, which utilizes 3-dimensional templating software to ascertain the appropriateness of the implant's geometry with the patient's anatomy. Furthermore, a 3-dimensional printed plastic model of the pelvis and/or femur can be constructed in order to complete a rehearsal procedure, which may be particularly helpful for those cases involving osteotomies. The literature on the use of robotic-assisted total hip arthroplasty in patients with DDH demonstrates improved component positioning in comparison to navigated as well as manual methods; however, studies with long-term follow-up in this patient population are lacking.

2023 American College of Rheumatology and American Association of Hip and Knee Surgeons Clinical Practice Guideline for the Optimal Timing of Elective Hip or Knee Arthroplasty for Patients With Symptomatic Moderate-to-Severe Osteoarthritis or Advanced Symptomatic Osteonecrosis With Secondary Arthritis for Whom Nonoperative Therapy Is Ineffective

OBJECTIVE

To develop evidence-based consensus recommendations for the optimal timing of hip and knee arthroplasty to improve patient-important outcomes including, but not limited to, pain, function, infection, hospitalization, and death at 1 year for patients with symptomatic and radiographic moderate-to-severe osteoarthritis or advanced symptomatic osteonecrosis with secondary arthritis of the hip or knee who have previously attempted nonoperative therapy, and for whom nonoperative therapy was ineffective, and who have chosen to undergo elective hip or knee arthroplasty (collectively referred to as TJA).

METHODS

We developed 13 clinically relevant population, intervention, comparator, outcomes (PICO) questions. After a systematic literature review, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to rate the quality of evidence (high, moderate, low, or very low), and evidence tables were created. A Voting Panel, including 13 physicians and patients, discussed the PICO questions until consensus was achieved on the direction (for/against) and strength (strong/conditional) of the recommendations.

RESULTS

The panel conditionally recommended against delaying TJA to pursue additional nonoperative treatment including physical therapy, nonsteroidal antiinflammatory drugs, ambulatory aids, and intraarticular injections. It conditionally recommended delaying TJA for nicotine reduction or cessation. The panel conditionally recommended delay for better glycemic control for patients who have diabetes mellitus, although no specific measure or level was identified. There was consensus that obesity by itself was not a reason for delay, but that weight loss should be strongly encouraged, and the increase in operative risk should be discussed. The panel conditionally recommended against delay in patients who have severe deformity or bone loss, or in patients who have a neuropathic joint. Evidence for all recommendations was graded as low or very low quality.

CONCLUSION

This guideline provides evidence-based recommendations regarding the optimal timing of TJA in patients who have symptomatic and radiographic moderate-to-severe osteoarthritis or advanced symptomatic osteonecrosis with secondary arthritis for whom nonoperative therapy was ineffective to improve patient-important outcomes, including pain, function, infection, hospitalization, and death at 1 year. We acknowledge that the evidence is of low quality primarily due to indirectness and hope future research will allow for further refinement of the recommendations.

Total Hip Arthroplasty: An Update on Navigation, Robotics, and Contemporary Advancements

While total hip arthroplasty (THA) remains effective for improvement of pain and function in patients with osteoarthritis and avascular necrosis, there remain areas of continued pursuit of excellence, including decreasing rates of dislocation, leg length discrepancy, implant loosening, and infection. This review article covers several bearing surfaces and articulations, computer-assisted navigation and robotic technology, and minimally invasive surgical approaches that have sought to improve such outcomes. Perhaps the most significant improvement to THA implant longevity has been the broad adoption of highly cross-linked polyethylene, with low wear rates. Similarly, navigation and robotic technology has proven to more reproducibly achieve intraoperative component positioning, which has demonstrated clinical benefit with decreased risk of dislocation in a number of studies. Given the projected increase in THA over the coming decades, continued investigation of effective incorporation of technology, soft tissue-sparing approaches, and durable implants is imperative to continued pursuit of improved outcomes in THA.

2023 American College of Rheumatology and American Association of Hip and Knee Surgeons Clinical Practice Guideline for the Optimal Timing of Elective Hip or Knee Arthroplasty for Patients With Symptomatic Moderate-to-Severe Osteoarthritis or Advanced Symptomatic Osteonecrosis With Secondary Arthritis for Whom Nonoperative Therapy Is Ineffective

OBJECTIVE

To develop evidence-based consensus recommendations for the optimal timing of hip and knee arthroplasty to improve patient-important outcomes including, but not limited to, pain, function, infection, hospitalization, and death at 1 year for patients with symptomatic and radiographic moderate-to-severe osteoarthritis or advanced symptomatic osteonecrosis with secondary arthritis of the hip or knee who have previously attempted nonoperative therapy, and for whom nonoperative therapy was ineffective, and who have chosen to undergo elective hip or knee arthroplasty (collectively referred to as TJA).

METHODS

We developed 13 clinically relevant population, intervention, comparator, outcomes (PICO) questions. After a systematic literature review, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to rate the quality of evidence (high, moderate, low, or very low), and evidence tables were created. A Voting Panel, including 13 physicians and patients, discussed the PICO questions until consensus was achieved on the direction (for/against) and strength (strong/conditional) of the recommendations.

RESULTS

The panel conditionally recommended against delaying TJA to pursue additional nonoperative treatment including physical therapy, nonsteroidal antiinflammatory drugs, ambulatory aids, and intraarticular injections. It conditionally recommended delaying TJA for nicotine reduction or cessation. The panel conditionally recommended delay for better glycemic control for patients who have diabetes mellitus, although no specific measure or level was identified. There was consensus that obesity by itself was not a reason for delay, but that weight loss should be strongly encouraged, and the increase in operative risk should be discussed. The panel conditionally recommended against delay in patients who have severe deformity or bone loss, or in patients who have a neuropathic joint. Evidence for all recommendations was graded as low or very low quality.

CONCLUSION

This guideline provides evidence-based recommendations regarding the optimal timing of TJA in patients who have symptomatic and radiographic moderate-to-severe osteoarthritis or advanced symptomatic osteonecrosis with secondary arthritis for whom nonoperative therapy was ineffective to improve patient-important outcomes, including pain, function, infection, hospitalization, and death at 1 year. We acknowledge that the evidence is of low quality primarily due to indirectness and hope future research will allow for further refinement of the recommendations.

Hemostatic Agents in Orthopedic Surgery

Controlling blood loss is a crucial aspect of orthopedic surgery. Hemostatic agents can be used intraoperatively in combination with antifibrinolytics as part of an overall strategy to limit blood loss. Several new hemostatic agents have recently come to the market designed specifically for vascular surgery but have found uses in other surgical fields, including orthopedics. This article reviews the mechanisms of action and best uses of various mechanical hemostats, active hemostats, flowable hemostats, and fibrin sealants for achieving hemostasis in orthopedic surgery. Mechanical and active hemostats have been reported to successfully decrease blood loss from cancellous bone, capillaries, and venules. Flowable hemostats are generally favorable for use in small spaces where the swelling capabilities of mechanical and active hemostats can be detrimental to surrounding structures. Sealants are best used for closing defects in tissues.

Outcomes After Revision Total Knee Arthroplasty from a Specific, Now-recalled Implant System

BACKGROUND

A specific total knee arthroplasty (TKA) implant system was recently recalled for high incidence of early polymeric wear and osteolysis. We analyzed the early outcomes of aseptic revision with these implants.

METHODS

We identified 202 aseptic revision TKAs of this implant system performed at a single institution between 2010 and 2020. Revision indications included aseptic loosening (n=120), instability (n=55), and polymeric wear/osteolysis (n=27). In 145 cases (72%) components were revised and 57 cases (28%) were isolated polyethylene insert exchange. Kaplan-Meier and Cox proportional hazards analyses were used to determine survivorship free from all-cause re-revision and re-revision risk factors.

RESULTS

At 2 and 5 years, survivorship free from all-cause re-revision was 89 and 76% in the polyethylene exchange cohort versus 92 and 84% in the component revision cohort (P=0.5). At 2 and 5 years, survivorship in revision with components from the same manufacturer was 89 and 80% compared to 95 and 86% in revision with components from a different manufacturer (P=0.2). Among re-revisions (n=30), cones (37%), sleeves (7%), hinge/distal femoral replacement implants were frequently used (13%). Men had increased risk for re-revision (Hazard Ratio=2.3, P=0.04).

CONCLUSIONS

In this series of aseptic revision TKAs performed on a now-recalled implant system, survivorship free from re-revision was lower than expected when components from the same manufacturer were utilized, but comparable to contemporary reports when both components were revised with an alternative implant system. Metaphyseal fixation with cones and sleeves as well as highly constrained implants were frequently utilized at time of re-revision TKA.

Unicompartmental Knee Arthroplasty Patients Have Lower Joint Awareness and Higher Function at 5 Years Compared to Total Knee Arthroplasties: A Matched Comparison

BACKGROUND

The purpose of this study was to evaluate postoperative outcomes at minimum 5-year follow-up in patients following unicompartmental knee arthroplasty (UKA) compared to a matched cohort of total knee arthroplasty (TKA) patients.

METHODS

Patients who had primarily medial compartment osteoarthritis (OA) who met criteria for medial UKA underwent TKA or medial UKA between 2014 and 2015 at a single institution, matched for age, sex, and body mass index. There were 127 UKAs in 120 patients and 118 TKAs in 116 patients included with minimum 5-year follow-up (range, 6 to 8). Mean age was 69 years (range, 59 to 79) and 71 years (range, 62 to 80) in the UKA and TKA groups, respectively (P = .049).

RESULTS

Patients who underwent UKA had significantly higher mean (±SD) Forgotten Joint Scores (87 ± 20 versus 59 ± 34, P < .001); higher Knee Society Scores (88 ± 14 versus 75 ± 21, P < .001); and lower Numeric Pain Rating Scores (0.8 ± 1.6 versus 1.9 ± 2.2, P < .001). Survivorship free from all-cause revision was 96% (95% CI = 93%-99%) and 99% (95% CI = 97%-100%) at 5 years for TKA and UKA, respectively (P = .52). There were 8 both component revisions in the TKA group within 5 years from the date of surgery and 2 UKA conversions to TKA after 5-year follow-up.

CONCLUSION

Patients who have medial compartment OA and underwent UKA had significantly lower joint awareness, decreased pain, improved function, and higher satisfaction compared to matched TKA patients at minimum 5-year follow-up while maintaining excellent survivorship.

Survivorship and Risk Factors for Re-Revision after Aseptic Revision Total Hip Arthroplasty in Patients Aged ≤55 Years

BACKGROUND

There is a relative paucity of literature on the outcomes after revision total hip arthroplasty (rTHA) in young patients. This study reports the survivorship and risk factors for re-revision in patients aged ≤55 years.

METHODS

We identified 354 patients undergoing aseptic nononcologic rTHA at mean follow-up of 5 years after revision, with mean age of 48 years, body mass index of 28 kg/m², and 64% female. Thirty-five (10%) patients underwent at least 1 previous rTHA. The main indications for rTHA included wear/osteolysis (21%), adverse local tissue reaction (21%), recurrent instability (20%), acetabular loosening (16%), and femoral loosening (7%); and included acetabular component-only rTHA in 149 patients (42%), femoral component-only rTHA in 46 patients (13%), both component rTHA in 44 patients (12%), and head/liner exchanges in patients 115 (33%). The Kaplan-Meier method was used to measure survivorship free from re-revision THA, and multivariate regression was used to identify risk factors for re-revision THA.

RESULTS

Sixty-two patients (18%) underwent re-revision THA at the mean time of 2.5 years, most commonly for instability (37%), aseptic loosening (27%), and prosthetic joint infection (15%). The rTHA survivorship from all-cause re-revision and reoperation was 83% and 79% at 5 years, respectively. Multivariate analysis demonstrated that patients undergoing femoral component only (hazard ratio 4.8, P = .014) and head/liner exchange rTHA (hazard ratio 2.5, P = .022) as risk factors for re-revision THA.

CONCLUSION

About 1 in 5 patients aged ≤55 years undergoing rTHA required re-revision THA at 5 years, most commonly for instability. The highest risk group included patients undergoing head/liner exchanges and isolated femoral component revisions.

Decreased Implant Survival is Associated With Younger Patients Undergoing Total Knee Arthroplasty

Background: Younger patients are undergoing total knee arthroplasty (TKA) at increasing rates and may face multiple revisions during their lifetimes due to mechanical complications or infections. Questions/Purposes: We sought to compare the early complication rates and revision-free implant-survival rates across age groups of patients undergoing TKA, with particular focus on implant survival in younger patients. Methods: We conducted a retrospective analysis of data taken from a national insurance database on patients who underwent primary TKA from 2007 to 2015. Kaplan-Meier curve survival analysis and log rank test were performed to evaluate revision rates in 7 age groups (younger than 40, 40-49, 50-59, 60-69, 70-79, 80-89, and 90 or more years of age). Complication rates were compared to rates in the age 60 to 79 years age groups using multiple logistic regression, controlling for baseline demographics and comorbidities. Results: There were 114,698 patients included in the analysis. Patients in the younger than 40 years, 40 to 49 years, and 50 to 59 years age groups had increased rates of early mechanical complications; 90-day readmission rates were significantly higher in those age groups as well. Revision-free implant survival at 5 years was significantly worse in patients younger than 60 years of age, particularly those less than 40 years, who had a 77% revision-free implant-survival rate at 5 years. Conclusions: Younger patients had a higher risk of early revision after TKA, as well as an increased rate of mechanical complications and readmissions at 90 days. These outcomes suggest more study is needed to better understand these discrepancies and to better guide preoperative counseling for young patients considering TKA.

Predicting Implant Size in Total Hip Arthroplasty

Background

Efficient resource management is becoming more important as the demand for total hip arthroplasty (THA) increases. The purpose of this study is to evaluate the ability of linear regression and Bayesian statistics in predicting implant size for THA using patient demographic variables.

Material and methods

A retrospective, single-institution joint-replacement registry review was performed on patients who underwent primary THA from 2005 to 2019. Demographic information was obtained along with primary THA implant data. A total of 11,730 acetabular and 8536 femoral components were included. A multivariable regression model was created on a training cohort of 80% of the sample and applied to the validation cohort (remaining 20%). Bayesian posterior probability methods were applied to the training cohort and then tested in the validation cohort to determine the 1%, 5%, and 10% error tolerance thresholds.

Results

The most predictive regression model included height, weight, and sex (cup: R² = 0.57, all P < .001; stem mediolateral size [M/L]: R² = 0.32, all P < .001). Removing weight had a minimal effect and resulted in a more parsimonious model (cup: R² = 0.56, all P < .001; stem M/L: R² = 0.32, all P < .001). Applying the posterior probability estimate to the validation cohort in the Bayesian model using height, weight, and sex demonstrated high accuracy in predicting the range of required implant sizes (95.3% cup and 90.4% stem M/L size).

Conclusion

Implant size in THA is correlated with demographic variables to accurately predict implant size using Bayesian modeling. Predictive models such as linear regression and Bayesian modeling can be used to improve operating room efficiency, supply chain inventory management, and decrease costs associated with THA.

High Satisfaction and Activity Levels After Total Hip Arthroplasty in Patients Under Age 21

BACKGROUND

With improved materials and bearing surfaces, the use of total hip arthroplasty (THA) in young patients is increasing. Functional outcomes and activity level are particularly relevant in this higher-demand patient population. There is a paucity of data on patient-reported outcomes and activity levels after THA in extremely young (<21 years old) patients.

METHODS

We identified 196 patients (222 hips) who underwent THA at age <21 years at our institution from 1982 to 2018. After applying exclusion criteria, 113 of 160 (70.6%) patients (129 hips) were available for follow-up. Patient activity levels and functional outcomes were evaluated using the UCLA activity score, Forgotten Joint Score (FJS), Hip Disability and Osteoarthritis Outcome Score for Joint Replacement, and a validated 5-question satisfaction survey. Survivorship and reasons for revision were recorded.

RESULTS

The mean age at surgery was 17.0 ± 2.8 years, and the mean follow-up was 13.2 years (range 2-38 years). The most common indications for THA were osteonecrosis (34%) and juvenile idiopathic arthritis (30%). The mean UCLA activity score was 5.9 ± 2.0, and 64% of patients reported a score ≥6. The mean FJS was 57.9 ± 31.0. The mean Hip Disability and Osteoarthritis Outcome Score for Joint Replacement score was 84.6 ± 16.6. Ninety percent of patients reported that they were very or somewhat satisfied with their surgery. At final follow-up, 27 of 129 (20.9%) hips had undergone revision surgery.

CONCLUSION

THA performed in patients under 21 years of age with end-stage hip disease allows for high levels of activity and satisfaction postoperatively, with most patients being able to participate in moderate recreational activities. These data may be useful for surgeons in planning for and counseling extremely young patients indicated for THA.

Contemporary Distal Femoral Replacements for Supracondylar Femoral Fractures Around Primary and Revision Total Knee Arthroplasties

BACKGROUND

There is a paucity of data on the outcomes of distal femoral replacements (DFRs) in patients with total knee arthroplasty (TKA) periprosthetic fractures. We sought to characterize these patients' survivorship free from rerevision.

METHODS

We retrospectively identified 49 patients, including 34 after primary TKA (primary cohort), 9 after revision TKA, and 6 conversions for failed open reduction and internal fixation (revision cohort) that underwent DFR for a periprosthetic femur fracture. The mean age was 76 years, and 40 patients (82%) were female. The mean follow-up was 4 years. Femoral fixation included 44 cemented stems (90%) and 5 cementless stems (10%). Survivorship free from rerevision was characterized by the Kaplan-Meier method; cox proportional regression was used to analyze the risk factors for rerevision.

RESULTS

Survivorship free from any rerevision at 5 years in the primary and revision cohort was 93% and 18%, respectively. The revision cohort had a 5.3× higher risk of re-revision (P = .008). Survivorship free from re-revision for aseptic loosening at 5 years in the primary and revision cohort was 93% and 53%, respectively. Two of the 3 patients with cementless stems in the primary cohort underwent early rerevision for aseptic loosening, but patients with prior primary TKAs treated with cemented femoral fixation (n = 31) had a 97% 5-year survivorship free from re-revision.

CONCLUSION

Patients with periprosthetic fractures around prior primary TKAs treated with DFRs with cemented femoral fixation had a 97% 5-year survivorship free from any re-revision. DFRs for periprosthetic femur fractures around revision TKAs or conversions of failed open reduction and internal fixations have a 5× increased risk of rerevision.

What Are the Benefits of Hip Resurfacing in Appropriate Patients? A Retrospective, Propensity Score-Matched Analysis

BACKGROUND

Hip arthritis is one of the major causes of disability worldwide. Hip resurfacing arthroplasty (HRA) has emerged in recent years as an alternative to total hip arthroplasty (THA), but complications of HRA have limited the patient population to younger male patients with primary osteoarthritis and large hip anatomy. How the functional benefits of HRA in this population compare with those of THA is not entirely clear.

QUESTIONS/PURPOSES

The primary aim of this study was to determine whether there were differences in hip disability and patient satisfaction with surgery between these two groups at 2 years after surgery, using patient-reported outcome measures (PROMs) and subjective measures of patient satisfaction. Additionally, we sought to determine whether there were differences in post-operative discharge disposition, revision rates, or adverse events.

METHODS

We searched an institutional database to identify patients undergoing unilateral HRA or THA between January 2007 and July 2011 who met today's recommended criteria for HRA: younger male patients with large-enough hip anatomy to make surgery viable (a femoral head of at least 48 mm in HRA patients and, in THA patients, an acetabular shell size of 54 mm, the minimum outer shell size that could accommodate a femoral head component of 48 mm; for matching purposes, acetabular shell size in THA was used as a surrogate for the femoral head size used in HRA). We used propensity score matching to control for potentially confounding pre-operative variables and administered the Hip Disability and Osteoarthritis Outcome Score (HOOS) survey, including its subdomains, at the 2-year mark. We also assessed differences between groups in Lower Extremity Activity Scale scores, 12-item Short Form Health Survey results, and answers regarding satisfaction with surgery. We calculated minimal detectable change, minimum clinically important change, and substantial clinical benefit using anchor-based techniques for multiple outcome measures.

RESULTS

There were 251 patients in each group. HRA patients scored significantly higher than THA patients on the 2-year HOOS sports and recreation (92 versus 87, respectively) and on rates of overall satisfaction (94% versus 89%, respectively). The HRA group also had a greater chance of achieving minimum clinically important change (18.75 points) in the HOOS sports and recreation subdomains than the THA group (97% versus 91%). No significant difference was found in 6-month adverse event rates. HRA patients also had a significantly shorter mean hospital stay, a higher rate of discharge to home, and a lower incidence of a "significant" limp after surgery.

CONCLUSION

HRA may provide a functional benefit in sports and recreation and greater satisfaction in patients who meet the current criteria for HRA. Because these benefits may be small, pre-operative counseling should focus on balancing the possible functional benefits against the longer-term risks associated with metal-on-metal bearings.

General Principles of the Surgical Management of Juvenile Inflammatory Arthritis

Surgical management of Juvenile Inflammatory Arthritis (JIA) presents many challenges for the patient, healthcare team and especially the orthopedic surgeon. Collaborative care efforts must be endorsed early on in order to facilitate maximal postoperative functional ability. Developmental levels, both physically and emotionally must be established preoperatively. It is important to determine bone age and growth plate closure to establish the best surgical intervention and avoid leg-length discrepancies later in life. Emotional maturity may impede the ability of the patient to manage pain or follow directions throughout the recuperative process. Surgical challenges require a team approach that includes rheumatologists who can manage disease modifying agents and the effects of discontinuing medications or planning surgery around dosing regimens in order to decrease immunosuppression. Managing multiple joint issues will require an expert team of occupational and physical therapists to prepare adaptive devices and rehabilitate patients who have significant functional limitations and decreased muscular strength. Because of an anticipated longer and more difficult recovery for JIA patients, case managers must engage in support systems and plan for postoperative care prior to surgery. Implant specific devices need to accommodate small bone structure, bone loss and complex deformities along with diaphyseal or epiphyseal dysplasia. Neurologic assessments will avoid cervical spine compromise during anesthesia administration. Bilateral procedures in the lower extremities should be considered whenever flexion contractures are present and should take place prior to upper extremity joint replacements. Restoring function to the hand and wrist takes priority over elbow and shoulder replacement, respectively. The key factors of appropriate surgical management in JIA patients are to decrease pain, restore function and avoid loss of ambulation at a young age. Extensive preoperative planning and communication with the patient, support system and healthcare team are warranted to address the complexities in this patient population.

Surgical Games: A Simulation-Based Structured Assessment of Orthopedic Surgery Resident Technical Skill

BACKGROUND

Simulation-based education and objective evaluation of surgical skill have been incorporated into many surgical training programs. We describe the development and implementation of a timed, multitask, station-based Surgical Games to evaluate orthopedic resident surgical skills.

METHODS

Participants in the study were postgraduate-year 2 to 5 orthopedic surgery residents from a single institution. Residents completed 4-timed simulated tasks: cadaveric carpal tunnel release (CTR), Sawbones model of total knee arthroplasty (TKA), Sawbones model of ankle fracture open reduction internal fixation (ORIF), and knee arthroscopy simulator (KAS) of removal of loose body. Evaluations were performed using standardized score sheets by attending surgeons. Resident performance was analyzed by postgraduate-year and number of weeks of prior task-related residency training.

RESULTS

A total of 32 residents were assessed at the 4 stations. Total scores were significantly different for CTR (p = 0.006), TKA (p = 0.05), and the KAS (p = 0.004) by year of training, but not for the ankle ORIF task. Residents with more task-specific experience performed significantly better on the KAS (p < 0.001), TKA (p = 0.002), and CTR (p = 0.02) tasks but not on the ankle ORIF task (p = 0.1). Overall, residents rated the exercise valuable to their education with mean scores of 3.9 ± 0.54 on a 5-point Likert Scale.

CONCLUSIONS

This Surgical Games exercise provided an objective evaluation of surgical skill that correlated with year-in-training and prior experience in skill-specific rotations for the KAS, TKA, and CTR tasks. This surgical skills assessment provided an opportunity for effective structured feedback and identification of areas for improvement.

Outcomes and complications following non-oncologic total femoral replacement

BACKGROUND

Non-oncologic total femoral replacement (TFR) is utilised as a limb-salvage option in the setting of massive bone loss during revision total hip arthroplasty (THA) and total knee arthroplasty (TKA). However, complication rates, including infection and reoperation, remain a concern.

METHODS

In this study, 16 consecutive TFRs from a single institution with an average clinical follow-up of 4 years were retrospectively reviewed. Indications for TFR, previous surgeries, implants used, complications, reoperations, and ambulatory status at final follow-up were recorded.

RESULTS

The reoperation rate was 50%, and those patients averaged 2 additional surgeries after TFR. The most common reason for reoperation was infection with a 33% incidence of a new periprosthetic infection and an overall infection rate of 44% (7/16). 6/7 were managed with irrigation and debridement and implant retention. Dual-mobility and constrained acetabular liners were used consistently, and no patient experienced a subsequent dislocation. At final follow-up, 81% were ambulatory but only 2 patients (13%) could walk without an assistive device. No patient required amputation.

CONCLUSIONS

While TFR achieved limb salvage in all patients with fair clinical outcomes, patients were at high risk for new or persistent infection and reoperation. Dual-mobility and constrained acetabular liners were effective in preventing dislocation is this cohort.

Predicting implant size in total knee arthroplasty using demographic variables

AIMS

The purpose of this investigation was to determine the relationship between height, weight, and sex with implant size in total knee arthroplasty (TKA) using a multivariate linear regression model and a Bayesian model.

METHODS

A retrospective review of an institutional registry was performed of primary TKAs performed between January 2005 and December 2016. Patient demographics including patient age, sex, height, weight, and body mass index (BMI) were obtained from registry and medical record review. In total, 8,100 primary TKAs were included. The mean age was 67.3 years (SD 9.5) with a mean BMI of 30.4 kg/m² (SD 6.3). The TKAs were randomly split into a training cohort (n = 4,022) and a testing cohort (n = 4,078). A multivariate linear regression model was created on the training cohort and then applied to the testing cohort . A Bayesian model was created based on the frequencies of implant sizes in the training cohort. The model was then applied to the testing cohort to determine the accuracy of the model at 1%, 5%, and 10% tolerance of inaccuracy.

RESULTS

Height had a relatively strong correlation with implant size (femoral component anteroposterior (AP) Pearson correlation coefficient (ρ) = 0.73, p < 0.001; tibial component mediolateral (ML) ρ = 0.77, p < 0.001). Weight had a moderately strong correlation with implant size, (femoral component AP ρ = 0.46, p < 0.001; tibial ML ρ = 0.48, p < 0.001). There was a significant linear correlation with height, weight, and sex with implant size (femoral component R² = 0.607, p < 0.001; tibial R² = 0.695, p < 0.001). The Bayesian model showed high accuracy in predicting the range of required implant sizes (94.4% for the femur and 96.6% for the tibia) accepting a 5% risk of inaccuracy.

CONCLUSION

Implant size was correlated with basic demographic variables including height, weight, and sex. The linear regression and Bayesian models accurately predicted required implant sizes across multiple manufacturers based on height, weight, and sex alone. These types of predictive models may help improve operating room and implant supply chain efficiency. Level of Evidence: Level IV Cite this article: Bone Joint J 2020;102-B(6 Supple A):85-90.

Postoperative outcomes of total knee arthroplasty compared to unicompartmental knee arthroplasty: A matched comparison

BACKGROUND

The purpose of this study was to evaluate early postoperative outcomes in patients following UKA (unicompartmental knee arthroplasty) compared to a matched cohort of TKA (total knee arthroplasty) patients.

METHODS

Patients who met radiographic criteria for a medial UKA who underwent either a TKA or UKA at a single institution were matched based on age, gender, and BMI.

RESULTS

One hundredy and fifty UKA in 138 patients and 150 TKA in 148 patients were included in this retrospective analysis. Mean age was 62.6 ± 9 years and 65.2 ± 9 years in the UKA and TKA groups respectively (p = .01). Patients who underwent UKA had significantly less pain at two and six weeks postoperatively compared to TKA patients with mean Numeric Pain Rating Scale (NPRS) scores of 3.7 ± 1.1 vs. 7.8 ± 1.2, p < .001 and 2.6 ± 1.3 vs. 4.6 ± 1.6, p < .001 respectively. Knee Society Scores (KSS) were higher in the UKA group at six weeks and two years postoperative (86.5 ± 2.8 vs. 81.4 ± 3.6, p < .001 and 89.5 ± 2.4 vs. 84.5 ± 3.3, p < .001 respectively). Return to work was faster in the UKA group (mean 20.6 ± 7.89 vs. 38.6 ± 6.23 days, p < .001). The UKA group also had higher mean Forgotten Joint Scores of 90.5 ± 3.6 vs. 79.5 ± 9.5 (p < .001).

CONCLUSIONS

Patients with primarily medial compartment OA who underwent UKA had less postoperative pain, earlier return to work, and higher KSS compared to a matched group who underwent TKA.

Complications associated with staged versus simultaneous bilateral total knee arthroplasty: An analysis of 7747 patients

BACKGROUND

Benefits of simultaneous bilateral total knee replacement (TKR) include lower costs, decreased hospital stay, and shorter rehabilitation. This study evaluated complications associated with simultaneous versus staged bilateral TKR within 12 months. We hypothesized that after controlling for comorbidities, the simultaneous group would have the highest rate of complications.

METHODS

This retrospective study analyzed the Humana subset of the PearlDiver Patient Records Database. CPT 27447 and associated modifiers were used to identify patients who underwent simultaneous or staged bilateral primary TKRs. Staged bilateral TKRs were performed within 12 months and were stratified by the time between procedures. Primary outcomes were the Centers for Medicare & Medicaid Services' publicly reported complications. Risks of complications were compared using multivariate logistic regression controlling for age, gender, and comorbidities.

RESULTS

Seven thousand seven hundred forty-seven patients underwent simultaneous or staged bilateral TKRs between January 2007 and April 2015. There were lower odds of transfusion and all-cause 90-day readmission but higher odds of mechanical complications and infection for all staged groups compared to the simultaneous. Patients whose staged surgeries were ≪3 months apart had significantly higher odds of undergoing manipulation under anesthesia (MUA).

CONCLUSIONS

Higher rates of blood transfusion and readmission were associated with simultaneous bilateral TKR, while higher rates of mechanical complications and infection were associated with staged bilateral TKR. MUA risk was highest in patients staged ≪3 months apart. While there are inherent risks to simultaneous bilateral TKR, surgeons and patients should also be aware of risks associated with staging the procedures.

LEVEL OF EVIDENCE

III.

Conversion of Hip Resurfacing With Retention of Monoblock Acetabular Shell Using Dual-Mobility Components

BACKGROUND

Retention of the acetabular component is an option during conversion from hip resurfacing arthroplasty (HRA) to total hip arthroplasty (THA). The purpose of this study was to compare clinical outcomes of conversion of the femoral resurfacing component with retained acetabular components (RAC) and use of dual-mobility femoral heads to outcomes of patients treated with both component (BC) revisions.

METHODS

A retrospective review was performed of the clinical outcomes of HRA to THA conversions performed at a single institution between 2008 and 2017.

RESULTS

Seventy-one conversions were included (27 RAC and 44 BC). Average age at time of conversion was 54.4 years (range, 30-68 years). Median time to conversion was 5.14 (2.77-7.41) years and median follow-up post-conversion was 1.7 (0.33-4.0) years. There were no significant differences in indications for conversion between the 2 groups with the majority performed for complications related to elevated metal ions and aseptic loosening. Harris Hip Scores improved from pre-conversion to post-conversion in both cohorts (P < .01). There were no significant differences in pre-conversion and post-conversion metal ion levels between the RAC and BC groups. Serum metal ion levels decreased significantly in both cohorts (P < .01). There were 6 additional revisions in the cohort (4 in BC, 2 in RAC) at a median 2.94 (1.99-3.85) years post-conversion. Two RAC patients had intraprosthetic dislocations with extensive polyethylene wear requiring acetabular revision at median 3.92 (3.85-3.98) years post-conversion. Overall, there were a higher number of complications in the BC group related to acetabular fracture, failure of osseointegration, and periprosthetic joint infection; however, this did not reach statistical significance (P = .27).

CONCLUSION

Salvage of an appropriately positioned, well-fixed HRA acetabular component is a reasonable option in the setting of conversion to THA using dual-mobility components. This technique avoids the morbidity of acetabular revision and was associated with a decrease in metal ion levels and improvements in short-term functional outcomes comparable to a BC revision.

Comparison of Expectations and Outcomes in Rheumatoid Arthritis Versus Osteoarthritis Patients Undergoing Total Knee Arthroplasty

BACKGROUND

We hypothesized that patients undergoing primary total knee arthroplasty (TKA) for rheumatoid arthritis (RA) would have different preoperative expectations compared to osteoarthritis (OA) patients, and that postoperative satisfaction would correlate with specific postoperative pain and functional domains.

METHODS

This is a retrospective cohort study of RA patients matched based on age, gender, American Society of Anesthesiologists score, and Charlson Comorbidity Index score 1:2 with OA patients (76 RA, 152 OA) who underwent primary TKA. The Hospital for Special Surgery Knee Replacement Expectations Survey, Visual Analogue Scale for Pain (VAS), Knee injury and Osteoarthritis Outcome Score (KOOS), and the Short Form-12 (SF-12) were compared at baseline and at 2 years postoperatively. Minimum clinically important differences (MCIDs) were calculated for KOOS and SF-12 subdomains.

RESULTS

Preoperatively, RA patients had lower expectations, worse VAS Pain, and worse KOOS Pain, Symptoms, and Activities of Daily Living (P < .05). However, at 2 years, RA patients had significantly larger improvements in VAS (P = .01) and these 3 KOOS subdomains (P < .05), achieving comparable absolute scores to OA patients. Overall, 86.1% of RA and 87.1% of OA patients were either somewhat or very satisfied with their TKA. Patient satisfaction correlated with VAS Pain and KOOS outcome scores in both groups. RA and OA patients had high rates of achieving MCID in SF-12 physical component scores and all 5 KOOS subdomains. A higher proportion of RA patients achieved MCID in KOOS Symptoms (98.4% vs 77.2%, P < .001).

CONCLUSION

RA patients had lower baseline expectations compared to OA patients. However, RA patients had greater improvements in KOOS and SF-12 subdomains, and there was no difference in satisfaction compared to OA patients after TKA.

Improving Estimates of Annual Survival Rates for Medial Unicompartmental Knee Arthroplasty, a Meta-Analysis

BACKGROUND

Medial unicompartmental knee arthroplasty (mUKA) is an increasingly popular treatment option for medial compartment knee osteoarthritis. Published mUKA survival rates have varied. The purpose of this meta-analysis was to provide pooled estimates of mUKA survival 5 and 10 years postoperatively.

METHODS

We included studies in English within the last 15 years with a clear description of mUKA failure. Random-effects models were used to pool complementary log-log transformed implant survival estimates at 5 and 10 years postoperatively. Between-study variance was estimated using the restricted maximum likelihood method. Between-study heterogeneity was tested using the χ2 test and quantified using the I² statistic. I² values <25%, 25%-75%, and >75% were considered low, moderate, and high, respectively. Multivariable meta-regression was used to assess the potential association of mean patient age and study start year with survival estimates at 5 and 10 years. All analyses were performed using the metafor and meta packages implemented in R software version 3.3.4 (R Foundation for Statistical Computing, Vienna, Austria).

RESULTS

Twenty-six studies met inclusion criteria, representing 42,791 knees. Study-level and pooled 5- and 10-year mUKA survival estimates were 95.3% (95% confidence interval, 93.6-96.6) and 91.3% (88.9-93.3), respectively. Between-study heterogeneity was high (>88%) for all years. Mean patient age and study start year explained only 12.3% and 30.7% of between-study heterogeneity at 5 and 10 years, respectively.

CONCLUSION

Five- and 10-year pooled mUKA survival estimates were 95.3% and 91.3%, respectively. These data establish better estimates of mUKA survivorship and can help when counseling patients considering mUKA.

Diagnosing Prosthetic Joint Infections in Patients With Inflammatory Arthritis: A Systematic Literature Review

BACKGROUND

Patients with inflammatory arthritis (IA) are at increased risk of prosthetic joint infections (PJI), yet differentiating between septic and aseptic failure is a challenge. The aim of our systematic review is to evaluate synovial biomarkers and their efficacy at diagnosing PJI in patients with IA.

METHODS

A comprehensive literature search was performed in the following databases from inception to January 2018: Ovid MEDLINE, Ovid EMBASE, and the Cochrane Library. Searches across the databases retrieved 367 results. Two of 5 reviewers independently screened a total of 298 citations. Discrepancies were resolved by a third reviewer. Twenty articles fit our criteria, but due to methodological differences findings could not be pooled for meta-analysis. For 5 studies, raw data were provided, pooled, and used to derive optimal diagnostic cut points.

RESULTS

Our final analysis included 1861 non-IA patients, including 426 patients with PJI, and 90 IA patients of whom 26 had PJI. There was a significant difference among the 4 groups for serum C-reactive protein (CRP), erythrocyte sedimentation rate, and synovial CRP, polymorphonuclear neutrophil percent, white blood cells, interleukin (IL)-6, IL-8, and IL-1b. Polymorphonuclear neutrophil percent had the highest sensitivity (95.2%) and specificity (85.0%) to detect infections with an optimum threshold of 78%.

CONCLUSION

While levels of synovial white blood cells, IL-6, IL-8, and serum CRP appear higher in patients with IA, there is overlap with those who are not infected. Further studies are needed to explore diagnostic tests that will better detect PJI in patients with IA.

A Novel Mobile Phone Text Messaging Platform Improves Collection of Patient-Reported Post-operative Pain and Opioid Use Following Orthopedic Surgery

BACKGROUND

Prospective collection of patient-reported opioid consumption and pain levels post-surgically may hold value in highlighting solutions related to the opioid crisis. Traditional methods for collecting patient-reported outcomes after surgery, such as paper surveys, often have poor response rates, and electronic messaging may offer more convenience and therefore yield more robust data.

QUESTIONS/PURPOSES

The purpose of this study was to evaluate whether a novel mobile phone short message service (SMS) platform would lead to better patient response rates to surveys on pain and opioid use than data-collection tools.

METHODS

An SMS text messaging platform was created and implemented between September 2017 and May 2018 at an orthopedic specialty hospital. The purpose was to collect reports on opioid consumption and pain levels twice a day for 6 weeks post-surgery from patients who had undergone total hip or knee arthroplasty or a single-level lumbar microdiscectomy or decompression spine surgery. Patients who responded to fewer than 50% of the text messages were excluded.

RESULTS

Our mobile phone text messaging platform was used by 183 patients, demonstrating a significantly higher response rate (96.1%) than our institution's post-operative email registry capture, as well as the majority of published response rates for post-operative outcomes captured through electronic and traditional data-collection systems. Response rate remained consistently high among the various surgeons and across patients, regardless of age.

CONCLUSIONS

This application of a widely available technology can improve the measurement of post-operative patient-reported outcomes. Such data can in turn be used in the development of strategies to reduce post-operative opioid use. The adoption of novel technologies at a patient level will play a key role in combating the opioid epidemic.

Short-term Complications After Revision Hip Arthroplasty for Prosthetic Joint Infection Are Increased Relative to Noninfectious Revisions

BACKGROUND

Periprosthetic joint infection (PJI) after total hip arthroplasty (THA) is associated with significant morbidity and cost. The purpose of this study was to determine how rates of perioperative complications, operative duration, and postoperative length of stay (LOS) in patients undergoing revision THA for PJI compare to primary THA and to revision THA for non-PJI.

METHODS

We used the National Surgical Quality Improvement Program registry from 2005 to 2015 to identify all patients who underwent primary and revision THA. Patients were placed into cohorts based on the surgical procedure and by indication, including (1) primary THA, (2) revision THA for PJI, and (3) revision THA for non-PJI. Differences in 30-day postoperative medical complications, hospital readmissions, operative duration, and LOS were compared using bivariate and multivariate analyses.

RESULTS

One lakh fourteen thousand five hundred five THA patients were identified, with 102,460 (89.5%) patients undergoing a primary THA and 12,045 (10.5%) undergoing a revision procedure. Of the 12,045 revision procedures, 10,777 (89.5%) were for non-PJI indications and 1268 (10.5%) were for PJI. Relative to primary THA, patients undergoing revision THA for PJI had an increased rate of total complications (odds ratio [OR] 3.96), sepsis (OR 13.15), deep surgical site infections (SSIs, OR 8.58), superficial SSI (OR 2.14, P = .002), nonhome discharge (OR 1.85), readmissions (OR 2.46), LOS (+3.0 days), and operative duration (+61 minutes). Compared with non-PJI revisions, PJI revisions had an increased rate of total complications (OR 2.42), sepsis (OR 5.51), deep SSI (OR 2.12), nonhome discharge (OR 1.47), and LOS (+1.8 days).

CONCLUSION

Revision THA for PJI is associated with increased postoperative complications, nonhome discharge, and LOS relative to non-PJI revision THA. Separate care pathways and reimbursement bundles should be considered for patients with PJI.

LEVEL OF EVIDENCE

III.

Component Placement Accuracy in Unicompartmental Knee Arthroplasty Is Improved with Robotic-Assisted Surgery: Will It Have an Effect on Outcomes?

Bell et al.'s "Improved Accuracy of Component Positioning with Robotic-Assisted Unicompartmental Knee Arthroplasty: Data from a Prospective, Randomized Controlled Study" compared the accuracy of a robotic-assisted unicompartmental knee arthroplasty (UKA) using the MAKO Robotic Interactive Orthopedic Arm (RIO) system to a conventional UKA using standardized instrumentation. This review examines the authors' findings and their relevance to clinical practice. Bell et al. conclude that the MAKO RIO system leads to more accurate implantation of both the tibial and femoral components in UKA in the sagittal, coronal, and axial planes. This well-designed, level I study suggests what many arthroplasty surgeons assume about robotic assistance, which admittedly is of unknown clinical significance at this time. Evaluating this article in the context of the current literature provides valuable insight into areas in need of future investigation. The effect of implant positioning on long-term clinical outcomes and implant survivorship remains unclear. Long-term follow-up studies are needed to determine the role of robotic-assisted arthroplasty in the future.

Authorship Trends in 30 Years of the Journal of Arthroplasty

BACKGROUND

While various studies have investigated trends in characteristics of authors in other medical literature, no study has examined these characteristics in the field of arthroplasty.

METHODS

A database was created of all articles published in The Journal of Arthroplasty in 1986, 1990, 1995, 2000, 2005, 2010, and 2015. Degree(s) of authors, number of authors, number of references, and region of institution were recorded.

RESULTS

A total of 1343 original articles were assessed over the study period. There was a significant increase in the number of authors per publication from 3.45 in 1986 to 4.98 in 2015 (P < .001) and number of references per article from 17.36 to 29.76 (P < .001). There was a significant increase in proportion of first authors with a bachelor's degree (P = .001), MD/PhD (P < .001), and MD/MBA (P = .016), with a significant decrease in first authors with an MD degree only (P < .001). There was a significant increase in number of last authors with an MD/PhD (P = .001) and MD/MBA (P = .003). There has been a significant growth in papers from outside North America (P = .007), with a decrease in articles from the UK/Ireland (P = .003) and an increase in contributions from the Far East (P < .001).

CONCLUSION

Trends of authorship characteristics in the arthroplasty literature largely mirror those seen in other medical literature including increased number of authors per article over time, changes in author qualifications, and increased contributions from international author groups.

Template-Directed Instrumentation Reduces Cost and Improves Efficiency for Total Knee Arthroplasty: An Economic Decision Analysis and Pilot Study

Template-directed instrumentation (TDI) for total knee arthroplasty (TKA) may streamline operating room (OR) workflow and reduce costs by preselecting implants and minimizing instrument tray burden. A decision model simulated the economics of TDI. Sensitivity analyses determined thresholds for model variables to ensure TDI success. A clinical pilot was reviewed. The accuracy of preoperative templates was validated, and 20 consecutive primary TKAs were performed using TDI. The model determined that preoperative component size estimation should be accurate to ±1 implant size for 50% of TKAs to implement TDI. The pilot showed that preoperative template accuracy exceeded 97%. There were statistically significant improvements in OR turnover time and in-room time for TDI compared to an historical cohort of TKAs. TDI reduces costs and improves OR efficiency.

Patient-Reported Allergies Are Associated With Poorer Patient Satisfaction and Outcomes After Lower Extremity Arthroplasty: A Retrospective Cohort Study

Anecdotal evidence suggests that patient-reported allergies (PRAs) may exhibit prognostic value for patient-reported outcomes after lower extremity arthroplasty. This study's purpose was to investigate associations between PRAs, patient satisfaction and outcomes after total hip arthroplasty (THA) and total knee arthroplasty (TKA). PRAs in 274 patients undergoing primary THA and 257 patients receiving primary TKA were reviewed retrospectively. Satisfaction scores, baseline Western Ontario and McMaster Universities Arthritis Index (WOMAC), 2-year postoperative WOMAC and length-of-stay (LOS) were analyzed with PRAs. Increasing number of PRAs was significantly associated with worse satisfaction scores and worse WOMAC scores for TKA and THA, and it was significantly associated with increased LOS for TKA. These results may have implications for patient counseling and risk-adjusted outcome models.