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Normal human bone marrow cells are critical for studies of hematopoiesis and as controls to assess toxicity. As cells from commercial vendors are expensive, many laboratories resort to cancer-free bone marrow specimens obtained during staging or to umbilical cord blood cells, which may be abnormal or reflect a much younger age group compared to the disease samples under study. We piloted the use of femoral heads as an alternative and inexpensive source of normal bone marrow. Femoral heads were obtained from 21 successive patients undergoing elective hip arthroplasty. Mononuclear cells (MNCs) were purified with Ficoll, and CD3+, CD14+, and CD34+ cells were purified with antibody-coated microbeads. The median yield of MNCs was 8.95 × 107 (range, 1.62 × 105–2.52 × 108), and the median yield of CD34+ cells was 1.40 × 106 (range, 3.60 × 105–9.90 × 106). Results of downstream applications including qRT-PCR, colony-forming assays, and ex vivo proliferation analysis were of high quality and comparable to those obtained with standard bone marrow aspirates. We conclude that femoral heads currently discarded as medical waste are a cost-efficient source of bone marrow cells for research use.

Total knee arthroplasty (TKA) improves the quality of life in those suffering from debilitating arthritis of the knee. However, little is known about the influence of TKA on restoring physical function. Prior studies have used artificial means, such as instrumented treadmills, to assess physical function after TKA. In this study an insole sensor device was used to quantify parameters of gait. The purpose of this study was to evaluate the ability of a wearable insole sensor device to measure immediate postoperative gait parameters at 2 weeks and 6 weeks following primary TKA and to determine if the device was suitable and sensitive enough to identify and measure potentially subtle changes in these measures at these early postoperative time periods. Twenty-nine patients with unilateral TKA, without contralateral knee pain, and aid-free walking before surgery were evaluated. An insole force sensor measured the postoperative parameters while walking a distance of 40 m on level ground at 2 and 6 weeks after TKA. The loading rate of the operated lower extremity was an average of 68.7% of the contralateral side at 2 weeks post-surgery and increased to 82.1% at 6 weeks post-surgery (p

Periprosthetic joint infection (PJI) is a devastating complication after total joint arthroplasty, carrying significant economic and personal burden. The goal of this study is to use an established database to analyze socioeconomic variables and assess their relationship to PJI. Additionally, we sought to evaluate whether socioeconomic factors, along with other known risk factors of PJI, when controlled for in a statistical model affected the familial risk of PJI.With approval from our Institutional Review Board we performed a population-based retrospective cohort study on all primary total joint arthroplasty cases of the hip or knee (n = 85,332), within a statewide database, between January 1996 and December 2013. We excluded 9854 patients due to age18 years, missing data, history of PJI prior to index procedure, and no evidence of 2-year follow-up (excluding those with PJI). Cases that developed PJI following the index procedure (n = 2282) were compared to those that did not (n = 73,196).After adjusting for covariates, patients with Medicaid as a primary payer were at greater risk for experiencing PJI (relative risk 1.40, 95% confidence interval [CI] 1.08-1.82, P = .01). There was no difference in risk between the groups associated with education level or median household income (all, P.05). First-degree relatives of patients who develop PJI (hazard ratio 1.66, 95% CI 1.23-2.24, P = .001) and first-degree and second-degree relatives combined (hazard ratio 1.39, 95% CI 1.09-1.77, P = .007) were at greater risk despite controlling for the above socioeconomic factors.Our study provides further support that genetic factors may underlie PJI as we did observe significant familial risk even after accounting for socioeconomic factors and payer status. We did not find a correlation between education level or household income and PJI; however, Medicaid payees were at increased risk. Continued study is needed to define a possible heritable disposition to PJI in an effort to optimize treatment and possibly prevent this complication.

Background We sought to determine the 10-year survivorship and reasons for revision for a fixed-bearing unicompartmental knee arthroplasty (UKA) design. In addition, we report on patient-reported outcomes and satisfaction and compare results of medial vs lateral compartment UKA and cemented vs cementless UKA with the same design. Methods We performed a retrospective cohort study on a single-surgeon case series using a single fixed-bearing UKA design in 158 consecutive patients who underwent 177 UKA procedures between July 2000 and December 2010. Cases missing follow-up within the last year, clinically or via telephone, were excluded (n = 17, 10%). A cumulative incidence competing risk model was used to evaluate the cumulative incidence of failure. Results Cumulative incidence of revision at a mean follow-up of 10 years was 13%. The majority of revisions (43%, 10/23) were for aseptic tibial component loosening, followed by progression of osteoarthritis (5/23, 22%). All Patient Reported Outcomes Measurement Information System measures demonstrated mean T-scores within one standard deviation from the US population norm. The mean Knee Injury and Osteoarthritis Outcome Score for Joint Replacement was 96.9 (range, 40-100). The mean pain score was 3.8 (range, 0-8). Eighty-six percent of patients were satisfied with the UKA. Conclusions At 10-year follow-up, the most common causes for revision were aseptic tibial loosening and adjacent compartment knee arthroplasty, and similar results were found for medial vs lateral compartment and for cemented vs cementless UKA. Surgeons should consider these findings for future UKA designs, and this represents the first study reporting on survivorship and outcomes of this specific UKA design.

Background Controversy continues to exist regarding the advisability of isolated polyethylene exchange (IPE) following total knee arthroplasty (TKA) for aseptic indications. We sought to compare the difference in the cumulative incidence of reoperation after IPE specifically for aseptic failure and to evaluate risk factors for failure. Methods We performed a retrospective cohort study of 122 knees revised for aseptic failure. Reasons for IPE in aseptic knees included: instability, polyethylene wear, arthrofibrosis, patella fracture, patellar resurfacing, patellar maltracking, extensor mechanism failure, patellectomy, and a custom polyethylene for correction of valgus deformity. The relatively high rate of mortality warranted a competing risk model to evaluate the cumulative incidence reoperation. Follow-up time was defined by years from IPE to date of reoperation or last follow-up. Generalized estimating equations were used for comparisons. Results Our analysis demonstrated an 87% (95% CI, 78–92%) survivorship free of reoperation at five years. Re-revision was secondary to aseptic failure, infection, and patellar malalignment. IPE for polyethylene wear was found to be protective and less likely to require reoperation (SHR 0.121 95% CI: 0.016–0.896, p = 0.039). Conclusions The current study suggests that when done for carefully selected indications, IPE may be an acceptable procedure and helpful alternative for aseptic TKA revisions, particularly when the pre-operative diagnosis is polyethylene wear. This is in contrast to prior reports and may represent a need to re-visit the role of isolated polyethylene exchange.

Background Enthusiasm for anterior-based approaches for total hip arthroplasty (THA) continues to increase but there is concern for increased complications during the learning curve period associated. This study aimed to investigate if there was a difference in perioperative variables, intraoperative and immediate postoperative complications, or patient-reported outcomes when transitioning from a mini-posterior approach (mPA) to an anterior-based muscle-sparing (ABMS) approach for THA. Methods Retrospective cohort study on the first 100 primary THA cases (n = 96 patients) of the senior author (August 2016 to August 2017) using the ABMS approach. These cases were compared to primary THA cases done the year prior (July 2015 to July 2016, n = 91 cases in 89 patients) using an mPA. Data were extracted and analyzed via gamma regression with robust standard errors and using generalized estimating equation regression. Results We found no difference in the estimated blood loss (P = .452) and surgical time (P = .564) between the cohorts. The ABMS cases had a slightly shorter length of stay (P = .001) with an adjusted mean length of stay of 1.53 days (95% confidence interval 1.4-1.6) compared to 1.85 days (95% confidence interval 1.8-1.9) in the mPA cases. There was no difference in the frequency of immediate postoperative complications (all, P > .05). There was no difference in the adjusted mean change in patient-reported outcomes (all P > .05). In the ABMS group, there was no difference in surgical time or physical function computerized adaptive test between the first 20 cases (reference) and each subsequent group of 20 cases (all P > .05). Conclusion This study demonstrates no associated learning curve for an experienced senior surgeon when switching routine THA approach from mPA to ABMS. We advise careful interpretation of our results, as they may not apply to all surgeons and practices. Level of Evidence Level III Therapeutic Study: retrospective comparative study.

There is very little literature on whether a simple radiographic measurement of native femoral head size correlates with implanted acetabular cup size. We hypothesized that there would be a high correlation between the radiographically measured native femoral head and implanted acetabular component size in primary total hip arthroplasty (THA). We conducted a retrospective study of 277 consecutive patients who underwent primary THA. Patients with prior contralateral THA or a history of congenital deformity were excluded (n = 95). We used the postoperative anteroposterior (AP) pelvic view to calibrate the image using known implanted femoral head component size. We then measured the diameter of the contralateral native femoral head under the assumption that femoral heads are generally symmetrical in patients. Two of the authors performed all measurements. To determine if native femoral head size was correlated with acetabular component size we used the Pearson correlation coefficient (r). There was a high correlation between contralateral native femoral head size and acetabular component size (r = 0.86, 95% confidence interval [CI]: 0.82–0.89). The median difference in radiographically measured native femoral head size and acetabular component size was 7 mm (interquartile range [IQR] = 5–8). Our data showed a high correlation between acetabular component size and radiographically measured contralateral native femoral head size, with the difference being 7 mm. In addition to verifying the actual femoral head size with calipers during surgery, this simple radiographic measurement, which could be done on the affected or contralateral hip, may help surgeons to plan better and improve preoperative templating in primary THA.

To our knowledge, no papers have reported the results of robotic-assisted surgery for sequential bilateral Total Knee Arthroplasty (TKA). Indeed, sequential bilateral TKA present several benefits, as one single anesthesia, surgical episode, hospitalization, and rehabilitation. The purpose of our study was to evaluate peri-operative outcomes and compare the complication rates, clinical outcomes, and implant positioning of sequential bilateral TKA performed with a robotic-assisted system versus a conventional technique.All patients who underwent a sequential bilateral robotic-assisted primary TKA (raTKA) in our institution between November 2019 and February 2021 were included. Twenty patients met the inclusion criteria and were matched with 20 sequential bilateral TKA performed with a conventional technique. The two groups were comparable for the demographic data and the preoperative parameters, including preoperative anticoagulation and ASA score. The minimum follow-up was 6 months.The operative time was significantly longer in the robotic group ( 0.0001), with a mean additional time of 29 min. There was no significant difference between both groups for postoperative blood loss, rate of blood transfusion, or postoperative pain. The average length of stay was 5 days. There was one early complication in the robotic group due to the tibial trackers. The functional outcomes were similar between both groups, except for the functional KSS score, which was better at 6 months in the robotic group (p 0.0001). The restoration of the knee alignment and the distal femoral anatomy were significantly better in the robotic group than in the conventional group.Despite a longer operative time, the peri-operative parameters of sequential bilateral TKA were similar between robotic and conventional techniques. Further, sequential bilateral raTKA was at least as safe as a conventional technique, without additional risk of medical complications.

BACKGROUND The effect of diabetes type on the risk of periprosthetic joint infection is not well documented. We hypothesized that patients with diabetes mellitus type 1 would be at greater risk for periprosthetic joint infection than those with diabetes mellitus type 2 and that a history of diabetic complications would be associated with an increased risk of periprosthetic joint infection. METHODS We performed a retrospective cohort study, within a statewide database, on all adult patients who underwent hip or knee arthroplasty, with follow-up of ≥2 years, from 1996 to 2013. Of the 75,478 patients included, 1,668 had type-1 diabetes and 18,186 had type-2 diabetes. Risk factors were calculated using Cox regression, adjusting for siblings and stratified by age. Logistic regression was used to analyze the effect of diabetic complications on the risk of periprosthetic joint infection, controlling for other known risks for periprosthetic joint infection. RESULTS There was no difference in age or sex between groups (p > 0.05). The frequency of periprosthetic joint infection in patients without diabetes was 2.6% compared with 4.3% in all patients with diabetes (relative risk, 1.47; p < 0.001). Patients with type-1 diabetes were at a 1.8 times greater risk for periprosthetic joint infection than patients with type-2 diabetes (7% compared with 4%; p < 0.001). The following diabetic complications increased the risk of periprosthetic joint infection: peripheral circulatory disorders (odds ratio [OR], 2.59 [95% confidence interval (CI), 1.70 to 3.94]), ketoacidosis (OR, 2.52 [95% CI, 1.51 to 4.19]), neurological manifestations (OR, 2.33 [95% CI, 1.96 to 2.78]), renal manifestations (OR, 2.15 [95% CI, 1.66 to 2.79]), and ophthalmic manifestations (OR, 1.76 [95% CI, 1.24 to 2.51]). The odds of periprosthetic joint infection increased with each added complication and patients with ≥4 complications were 9 times more likely to have a periprosthetic joint infection than patients with uncomplicated diabetes (OR, 9.47 [95% CI, 4.97 to 18.03]). Overweight and obese patients with type-2 diabetes and underweight patients with type-1 diabetes were at greater risk for periprosthetic joint infection compared with the general population (all p < 0.05). CONCLUSIONS Our data showed an increased risk of periprosthetic joint infection in patients with type-1 diabetes compared with those with type-2 diabetes, along with an increasing risk associated with additional diabetic complications. These findings emphasize the need to better understand the medical history of patients with diabetes for more appropriate risk management. LEVEL OF EVIDENCE Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Background: We evaluated the early outcomes, including all-cause revisions, aseptic revisions, and reoperations after revision total hip arthroplasty (THA) using a single modern modular femoral stem design. Methods: A retrospective cohort study on a consecutive series of 62 patients (65 hips) who underwent revision THA with a modern modular femoral stem system, between January 2011 and October 2015, at a single academic medical center was performed. A cumulative incidence competing risk model was used to evaluate the cumulative incidence of failure with death as the competing risk. Results: The cumulative incidence rate of all-cause revision THA was 14.5% (95% confidence interval [CI], 6%–24%) at 2 years when accounting for the competing risk of death. The rate of aseptic revisions was 6.8% (95% CI, 0.1%–13%), and the rate of all-cause reoperations was 21.6% (95% CI, 11%–31%). Ten THA cases (15%) underwent re-revision THA for any reason: five for infection and five for aseptic failures. The mean time to re-revision was 1 year (range, 0.04–5.34). Patients with a preoperative Mallory classification of 3 or more were at greater risk for reoperation (sub-hazard rate, 3.84; 95% CI, 1.54–9.53; P = .004). Conclusions: Although the high incidence of reoperation illustrates the complexity of the revision THA population, particularly related to infection and joint instability, the relatively low rate of aseptic failures, minimal radiographic subsidence, and the lack of modular junctional failures suggest that the use of this modular revision THA system may provide adequate fixation and could be considered as a viable treatment option in the setting of revision THA. Keywords: Revision total hip arthroplasty, Modular femoral implants, Femoral bone loss, Aseptic loosening, Competing risks survival

Background and objectivesThe objective of the study was to determine if injection of local anesthetic into the vastus medialis and sartorius muscles adjacent to the adductor canal produces sensory changes comparable with adductor canal block (ACB). This could result in a technically easier and potentially safer alternative to ACB.MethodsIn this randomized controlled trial, patients received either ACB (n=20) or a simplified adductor canal (SAC) block performed using a new fenestrated nerve block needle (n=20). The time to perform each block as well as the number of attempts to position the needle were evaluated. A non-inferiority test was used to compare pain scores and opioid requirements for the ACB and the SAC block.ResultsThe SAC block was performed more rapidly, with fewer needle passes, and had a higher success rate than the ACB. Three block failures and two vessel punctures were observed in the ACB group, while none of these events occurred in SAC block patients. Analgesia and opioid consumption for patients treated with the SAC block were not inferior to ACB.ConclusionThe SAC block is technically easier to perform and potentially safer than ACB. This procedure can be performed using easily visible ultrasound landmarks and has the potential for use among a wide range of healthcare providers.Trial registration numberNCT02786888.

We describe 3 cases of DePuy Pinnacle polyethylene dissociations, their presentations, and treatment. A 34-year-old female with arthritis secondary to dysplasia, a 51-year-old male with avascular necrosis of the femoral head, and a 57-year-old female with osteoarthritis were treated with total hip arthroplasty. Acute nontraumatic polyethylene liner dissociations occurred at 31, 42, and 2 months postoperatively. They were treated with component retention and modular femoral head and liner revision. The 51-year-old male subsequently developed a prosthetic joint infection requiring explant of his components. Although dissociation of polyethylene liners from the DePuy Pinnacle acetabular components is an uncommon complication, this problem may increase in prevalence with longer term follow-up, and vigilance is recommended. Keywords: Modular acetabular components, Polyethylene liner dissociation, DePuy, Pinnacle

In complex primary and revision total knee arthroplasty (TKA), rotating-hinge TKA (RH-TKA) prostheses play an important role. Compared to early fixed-hinge knee designs, new implants that include rotating platforms and improved hinge constructs may offer improvements in both survival and clinical outcomes. We sought to evaluate early survival following complex primary and revision TKA with a rotating-hinge knee prosthesis. We retrospectively reviewed a consecutive series of patients (n=47, 48 knees) who underwent revision TKA using an RH-TKA system. The mean age was 73 years (range, 37 - 86). The mean body mass index was 29 (range, 16.3 - 45.9) and the median ASA score was 3 (IQR, 2 - 3). As mortality was high, we performed a Kaplan-Meier analysis to evaluate survival, with death as failure. The median follow-up was 2.5 years (range, 0.07 - 9.8). Revision-free survival was 97% at a median 2.5 years of follow-up. Overall mortality was 46% (17/37) and survival free from death was 69% (49% - 82%) at a median of 2.5 years. Most reoperations were due to infection (5/12), following by wound-related complications (2/12) and hematomas (2/12). A high postoperative complication rate and mortality are evident in TKA using a hinged knee prosthesis in complex revision TKA. If the indication and surgical technique are matched to the complexity of the case, this type of implant offers a feasible salvage procedure.

In complex primary and revision total knee arthroplasty (TKA), rotating-hinge TKA (RH-TKA) prostheses play an important role. Compared to early fixed-hinge knee designs, new implants that include rotating platforms and improved hinge constructs may offer improvements in both survival and clinical outcomes. We sought to evaluate early survival following complex primary and revision TKA with a rotating-hinge knee prosthesis. We retrospectively reviewed a consecutive series of patients (n=47, 48 knees) who underwent revision TKA using an RH-TKA system. The mean age was 73 years (range, 37 – 86). The mean body mass index was 29 (range, 16.3 – 45.9) and the median ASA score was 3 (IQR, 2 – 3). As mortality was high, we performed a Kaplan-Meier analysis to evaluate survival, with death as failure. The median follow-up was 2.5 years (range, 0.07 – 9.8). Revision-free survival was 97% at a median 2.5 years of follow-up. Overall mortality was 46% (17/37) and survival free from death was 69% (49% - 82%) at a median of 2.5 years. Most reoperations were due to infection (5/12), following by wound-related complications (2/12) and hematomas (2/12). A high postoperative complication rate and mortality are evident in TKA using a hinged knee prosthesis in complex revision TKA. If the indication and surgical technique are matched to the complexity of the case, this type of implant offers a feasible salvage procedure.

Background: The purpose of this study was to compare the frequency of postoperative stiffness requiring manipulation under anesthesia (MUA) before and after switching from the intraoperative use of liposomal bupivacaine (LB). Methods: This was an institutional review board (IRB)-exempt retrospective cohort study (IRB#71733) on all patients who underwent primary total knee arthroplasty (TKA) by a single surgeon between April 2016 and December 2017. We compared 169 knees that received LB group to 167 knees that received a modified Ranawat cocktail (MR group). Perioperative care pathways remained consistent during the study period, as were requirements for MUA which included flexion range of motion below approximately 90 at 6–12 weeks. To compare the incidence of MUA between the groups, a population-averaged Poisson regression analysis was used. Results: The two groups were similar, with mean age of 63 (range 31–91) in the LB group and 64 (range 42–84) in the MR group, a preponderance of females in both groups ( p = 0.866), similar preoperative knee flexion between groups ( p = 0.162), and similar Patient-Reported Outcomes Measurement Information System scores. The frequency of MUA, however, was significantly lower in the MR group (LB: 7.7% [95% CI 3.7–12%] vs. MR: 2.4% [95% CI Conclusions: In summary, this is a novel report of a potentially previously unrecognized increased incidence of MUA associated with the use of LB compared with a MR cocktail. Given no other notable changes to the perioperative care or MUA thresholds following TKA, the reasons for these findings are unclear but deserve additional investigation.

Biofeedback following total knee arthroplasty (TKA) seems to be a feasible approach to improve rehabilitation, outcomes, mobility and reduce pain. This systematic review gives the practicing orthopedic surgeon a summary of what is available and how biofeedback affects clinical outcomes. We reviewed the current literature regarding methods, devices and effects of biofeedback in patients who underwent total knee arthroplasty. Embase, Pubmed, Web of Science, and Cochrane Central Register of Controlled Trials were searched from inception to May 2018 for the following keywords: Biofeedback OR Feedback AND Total Knee Arthroplasty OR TKA. Data were extracted according to a predefined setting (see Protocol for systematic review on PROSPEO). Devices used for biofeedback were recorded. Demographics, training methods and effects were also collected. The search resulted in 380 potentially eligible studies from which 11 met all inclusion criteria including 7 randomized controlled trials (RCTs), 3 cohort studies, and 1 cross-sectional study. A total of 416 patients with unilateral TKA were included, with an average of 37.8 patients per study. In patients with TKA, significant improvements in activity scores or pain were reported by 9 of 11 studies. Only two of the studies reported no significant influence of the feedback on the chosen outcome parameters. Devices for biofeedback varied between studies and included the use of a goniometer, force plate, balance board, treadmill, and/or electromyography (EMG). The most common type of feedback was visual followed by audio, with one study mentioning that the audio mode was preferred by the patients as it was easier to handle. Overall, 5 out of 6 different methods demonstrated a potential value for improving mobility and decreasing pain. This review suggests that biofeedback in early postoperative rehabilitation after TKA is effective in improving gait symmetry, reducing pain and increasing activity level. It should be noted that the great variety of devices used for feedback limits comparisons between studies. IIa.

Background Patient delivery of care satisfaction surveys have emerged as instruments to assess the quality of health care at both the hospital and provider levels. We evaluated the correlation between these care satisfaction surveys and patient-reported outcomes (PROs). Methods We reviewed secondary data on 540 patients with 540 random visits who underwent primary total joint arthroplasty between January 2014 and February 2017. The Press Ganey Outpatient Medical Practice Survey was collected from outpatient clinical encounters to measure patient satisfaction with their experience and matched to PRO measures from the same encounter. The PROs evaluated included the Patient-Reported Outcomes Measurement Information System physical function computerized adaptive test, v1.2, and the Patient-Reported Outcomes Measurement Information System Global 10 health survey. In addition to the random selection, we reviewed separate cross-sections of the data including preoperative visits within 90 days of the index procedure, all postoperative visits at least 1 year from the index procedure, and the magnitude of change in PRO scores from preoperative to a minimum 1-year postoperative visit. Data were evaluated using the Spearman correlation coefficient (rs). Results There was little if any correlation between the Press Ganey scores and PROs at all time points evaluated (all, rs: −0.13 to 0.14). When evaluating knee and hip arthroplasty cases separately, the data demonstrated similar results (all, rs: −0.33 to 0.18). Conclusion We found little, if any, correlation between a patient’s satisfaction with their care experience and their own perception of physical function and global health measures at all time points evaluated. These data question the utility of these scores as surrogate measures of health care quality, especially when reimbursements become tied to these metrics.

AimsFor this retrospective cohort study, patients aged ≤ 30 years (very young) who underwent total hip arthroplasty (THA) were compared with patients aged ≥ 60 years (elderly) to evaluate the rate of revision arthroplasty, implant survival, the indications for revision, the complications, and the patient-reported outcomes.Patients and MethodsWe retrospectively reviewed all patients who underwent primary THA between January 2000 and May 2015 from our institutional database. A total of 145 very young and 1359 elderly patients were reviewed. The mean follow-up was 5.3 years (1 to 18). Logistic generalized estimating equations were used to compare characteristics and the revision rate. Survival was evaluated using Kaplan–Meier curves and hazard rates were created using Cox regression.ResultsThe overall revision rate was 11% (16/145) in the very young and 3.83% (52/1359) in the elderly groups (odds ratio (OR) 2.58, 95% confidence interval (CI) 1.43 to 4.63). After adjusting for the American Society of Anesthesiologists (ASA) score, gender, and a history of previous surgery in a time-to-event model, the risk of revision remained greater in the very young (adjusted hazard ratio (HR) 2.48, 95% CI 1.34 to 4.58). Survival at ten years was 82% (95% CI, 71 to 89) in the very young and 96% (95% CI, 94 to 97) in the elderly group (p ConclusionThe overall revision rate was greater in very young THA patients. This was largely explained by the use of MoM bearings. Young patients with non-MoM bearings had high survivorship with similar complication profiles to patients aged ≥ 60 years. Cite this article: Bone Joint J 2018;100-B:867–74.

Background To determine if there was a difference in the change in patient-reported physical function (PF) between nondepressed and medically treated depressed or untreated depressed total joint arthroplasty (TJA) patients. Methods This is an Institutional Review Board exempt retrospective review of 280 TJA cases from March 2014 to May 2016. Patient-reported PF was measured as part of the routine care via the Patient Reported Outcomes Measurement Information System PF computerized adaptive test. Linear generalized estimating equation regression analyses were used. Results Untreated depressed cases demonstrated much smaller gains in PF scores compared to nondepressed patients (P = .020). Additionally, although treated and untreated depressed patients had statistically similar preoperative and postoperative PF scores (P > .05), untreated depressed cases experienced a lower magnitude of change (P = .015). Conclusion Medically treated depressed patients may have similar PF gains as nondepressed patients. Larger prospective studies may help identify whether screening for untreated depression and subsequent treatment leads to improved outcomes.

Background Adding value in a university-based academic health care system provides unique challenges when compared to other health care delivery models. Herein, we describe our experience in adding value to joint arthroplasty care at the University of Utah, where the concept of value-based health care reform has become an embraced and driving force. Methods To improve the value, new resources were needed for care redesign, physician leadership, and engagement in alternative payment models. The changes that occurred at our institution are described. Results Real-time data and knowledgeable personnel working behind the scenes, while physicians provide clinical care, help move clinical pathway redesigns. Engaged physicians are essential to the successful implementation of value creation and care pathway redesign that can lead to improvements in value. An investment of money and resources toward added infrastructure and personnel is often needed to realize large-scale improvements. Alignment of providers, payers, and hospital administration, including by means of gainsharing programs, can lead to improvements. Conclusion Although significant care pathway redesign efforts may realize substantial initial cost savings, savings may be asymptotic in nature, which calls into question the likely sustainability of programs that incentivize or penalize payments based on historical targets.

A step-by-step approach to creating a comprehensive patient education, expectation, and management program is described with the aim of reducing discharges to post-acute care centers (PACs) following total joint arthroplasty (TJA). We hypothesized that by lowering discharges to PACs, readmissions and reoperations would also decrease.Following the implementation of a multi-faceted patient education and management program, we retrospectively reviewed 927 TJAs who underwent surgery 12 months before (n = 465) and after (n = 462) the program was implemented. To assess the exposure of the pathway on discharge disposition as well as institutional 30-day and 90-day readmissions and reoperations, a modified Poisson regression was used.There was a 20% absolute reduction in discharges to PACs (0.001). The frequency of 30-day readmissions was greater in patients who underwent TJA before implementation (incidence rate ratio [IRR] 1.93, 95% confidence interval [CI] 1.01-3.69). The risk for 90-day readmissions (IRR 1.70, 95% CI 1.20-2.40) and reoperations (IRR 1.67, 95% CI 1.12-2.53) was greater prior to implementation. Discharge to PACs was associated with 2.4 and 3.10 times greater risk for 30-day readmissions (95% CI 1.28-4.56) and 30-day reoperations (95% CI 1.40-7.0), respectively. Patients discharged to PACs were also at greater risk for both 90-day readmissions (IRR 1.59, 95% CI 1.08-2.32) and 90-day reoperations (IRR 1.75, 95% CI 1.12-2.73).Our program led to a reduction in the number of patients being discharged to PACs following TJA, while also demonstrating a reduction in readmission and reoperations. Additionally, discharge to these facilities was an independent risk factor for these complications.

Background: Double hindfoot arthrodesis is a reliable treatment option in lower extremity deformity and arthritis. Single (medial) and 2-incision techniques have been described. The purpose of this study was to evaluate the extent of cartilage debrided in each approach and to evaluate the competency of the deltoid ligament. Methods: Eight matched pairs of cadaveric specimens were acquired. One limb from each pair was randomly assigned to the single medial incision and the other to the 2-incision technique. Stress radiographs were obtained prior to dissection to evaluate for valgus tibiotalar tilt. The talonavicular and subtalar articular surfaces were denuded of cartilage and the joints disarticulated. The percentage of cartilage debrided was determined using ImageJ software. Postoperative tibiotalar tilt was measured with a technique and threshold previously described by our group. The intraclass correlation coefficient was calculated to determine inter- and intraobserver reliability. Results: The single medial incision demonstrated significantly less cartilage denuded than the 2-incision technique at the talar head (61.1% ± 20.4% vs 88.1% ± 6.1%, P < .001), and the posterior facets of the talus (53.5% ± 7.6% vs 73.6% ± 7.0%, P < .001) and calcaneus (55.3% ± 16.5% vs 81.0% ± 7.4%, P = .001). Overall, 75% of specimens that underwent a single medial incision approach demonstrated increased valgus tibiotalar tilt postdissection, whereas none that underwent the 2-incision technique developed increased tibiotalar tilt ( P < .01). The average tibiotalar tilt among these specimens was 4.6 ± 1.3 degrees (range 2.5-5.7 degrees). For all measurements, the intraclass correlation coefficient was greater than 0.8. Conclusion: The posterior facet of the subtalar joint and talar head are at risk of subtotal debridement, as well as increased tibiotalar tilt with the single medial incision technique. Adequate debridement may require greater soft tissue dissection, possibly at the expense of medial ankle stability. Level of Evidence: Level III, retrospective cohort study.

Background Developmental dysplasia of the hip (DDH) is a recognized cause of secondary arthritis, which may eventually lead to total hip arthroplasty (THA). An understanding of the common acetabular and femoral morphologic abnormalities will aid the surgeon in preparing for the complexity of the surgical case. Methods We present the challenges associated with acetabular and femoral morphologies that may be present in the dysplastic hip and discuss surgical options to consider when performing THA. In addition, common complications associated with this population are reviewed. Results The complexity of THA in the DDH patient is due to a broad range of pathomorphologic changes of the acetabulum and femur, as well as the diverse and often younger age of these patients. As such, THA in the DDH patient may offer a typical primary hip arthroplasty or be a highly complex reconstruction. It is important to be familiar with all the subtleties associated with DDH in the THA population. The surgeon must be prepared for bone deficiency when reconstructing the acetabulum and should place the component low and medial (at the anatomic hip center), and avoid oversizing the acetabular component. Femoral dysplasia is also complex and variable, and the surgeon must be prepared for different stem choices that allow for decoupling of the metaphyseal stem fit from the implanted stem version. In Crowe III and IV dysplasia, femoral derotation/shortening osteotomy may be required. Many complications associated with THA in the DDH patient may be mitigated with careful planning and surgical technique. Conclusion Performed correctly, THA can yield excellent results in this complex patient population.

BACKGROUND It is estimated that the cost to treat periprosthetic joint infection in the United States will approach $1.62 billion by 2020. Thus, the need to better understand the pathogenesis of periprosthetic joint infection is evident. We performed a population-based, retrospective cohort study to determine if familial clustering of periprosthetic joint infection was observed. METHODS Analyses were conducted using software developed at the Utah Population Database (UPDB) in conjunction with the software package R. The cohort was obtained by querying the UPDB for all patients undergoing total joint arthroplasty and for those patients who had subsequent periprosthetic joint infection. The magnitude of familial risk was estimated by hazard ratios (HRs) from Cox regression models to assess the relative risk of periprosthetic joint infection in relatives and spouses. Using percentiles for age strata, we adjusted for sex, body mass index (BMI) of ≥30 kg/m, and a history of smoking, diabetes, and/or end-stage renal disease. Additionally, we identified families with excess clustering of periprosthetic joint infection above that expected in the population using the familial standardized incidence ratio. RESULTS A total of 66,985 patients underwent total joint arthroplasty and 1,530 patients (2.3%) had a periprosthetic joint infection. The risk of periprosthetic joint infection following total joint arthroplasty was elevated in first-degree relatives (HR, 2.16 [95% confidence interval (CI), 1.29 to 3.59]) and combined first and second-degree relatives (HR, 1.79 [95% CI, 1.22 to 2.62]). Further, 116 high-risk pedigrees with a familial standardized incidence ratio of >2 and a p value of

A less-invasive modification of the approach to periacetabular osteotomy (PAO) has recently been popularized by sparing the rectus femoris origin (RS-PAO). The RS-PAO approach with its lack of intra-articular inspection and associated treatment is novel, and there are few published results on the outcomes following this technique. We report on a consecutive series of RS-PAO cases, including patient reported outcomes (PROs), acetabular fragment reorientation, and complications. We reviewed a consecutive series of 103 patients (103 procedures) who underwent RS-PAO from June 2012 to January 2016 with a mean 2-year follow-up. We collected PROs, radiographic, and clinical outcomes. PROs consisted of PROMIS (Patient Reported Outcomes Measurement Information System) measures covering the domains of physical function, mental health, and a numeric pain score (NPS). Physical function and mental health were reported as standardized T-scores. Appropriate bivariate statistics were used for the analyses. Physical function improved from a preoperative mean of 39.9 (95% confidence interval [CI], 38.0–42.0) to a postoperative value of 50.0 T-score units (95% CI, 47.01–52.7; dav = 1.2). The PROMIS global mental-health T-scores improved from a preoperative median of 45.8 (interquartile range [IQR], 41.1–50.8) to a postoperative value of 53.3 (IQR, 50.8–59.0; p

Intraoperative fluoroscopy is commonly used to both guide the osteotomy and judge correction of the acetabular fragment in periacetabular osteotomy (PAO). Prior studies that have compared intraoperative fluoroscopic correction with postoperative radiographic correction were small studies that did not report intra- or interreader reliability. (1) What is the correlation between intraoperative fluoroscopic correction in PAO compared with the correction seen on postoperative radiographs? (2) What is the reliability of radiographic measures of correction in PAO? We performed a retrospective study of 121 patients (141 hips) who underwent PAO for symptomatic hip dysplasia at a tertiary referral center. Patients were included in the study if they had preoperative radiographs, intraoperative fluoroscopy, and minimum 6-week postoperative radiographs. Of the 272 PAO procedures performed in this time period, 61 patients who underwent PAO for retroversion and five patients with a history of Perthes disease were excluded as a result of the inability for these radiographic measures to judge fragment correction in PAOs for retroversion and the difficulty in measurement in post-Perthes deformity. Of the 206 PAOs performed for symptomatic acetabular dysplasia, 65 (32%) could not be analyzed because they lacked appropriate preoperative films, leaving 141 PAOs in 121 patients for analysis. The patients lacking appropriate preoperative films had them performed at an outside facility or had plain films that have since been destroyed. The lateral center-edge angle (LCEA) and acetabular index (AI) on the fluoroscopic views and postoperative radiographs were measured by two authors. The concordance between the amount of correction on intraoperative fluoroscopy and minimum 6-week postoperative measurements was analyzed using the concordance correlation coefficient (rc) and a Bland–Altman analysis. Intra- and interrater reliability was calculated between measurements. The amount of intraoperative correction of LCEA as measured on fluoroscopic images demonstrated substantial agreement with postoperative radiographs (rc = 0.79; 95% confidence interval [CI], 0.73–0.85; p 0.81). Intraoperative fluoroscopy is an accurate and reliable measure of correction of lateral coverage of the acetabular fragment during PAO. Further studies on measures of anterior coverage and acetabular version are needed to validate intraoperative fluoroscopic correction in these planes. Level III, diagnostic study.

To evaluate the convergent validity, precision, and completion times for the Physical Function Computerized Adaptive Test (PF-CAT) in a sports medicine patient population relative to standard measures of knee and shoulder function.We reviewed all patient visits from April through September 2014 with either knee or shoulder complaints from a university-based sports medicine clinic, during which PF-CAT, Single Assessment Numerical Evaluation (SANE), Simple Shoulder Test (SST), and American Shoulder and Elbow Surgeons (ASES) outcome scores for shoulder patients and PF-CAT, SANE, and International Knee Documentation Committee (IKDC) scores for knee patients were obtained, with an initial visit or one follow-up visit included in the study. Spearman correlation was used to evaluate pairwise agreement among scores. The McNemar χIn total, 415 shoulder and 450 knee clinical evaluations qualified for inclusion in the study. A high correlation was found between IKDC and PF-CAT scores (r = 0.75, P.0001), and a moderately high correlation was found between PF-CAT and both SST (r = 0.68, P.0001) and ASES (r = 0.63, P.0001) scores. Maximum differences in the sum of floor-ceiling values versus the PF-CAT were 15% for the SST (P.0001), 2.5% for the ASES (ceiling only, P = .0133), and 5.8% for the shoulder SANE (floor P = .0012, ceiling P = .0269). The PF-CAT had values of 0.4% for the shoulder and 0.6% for the knee. Zero percent of IKDC scores but 6.9% of knee SANE scores hit floor or ceiling values (floor P = .0019, ceiling P = .0007). The PF-CAT median completion time was lower at 55 seconds versus 268 seconds for the IKDC assessment (P.0001), whereas shoulder patients' times were 61, 139, and 116 seconds for the PF-CAT, SST, and ASES evaluation, respectively (P.0001).The PF-CAT showed a high correlation with IKDC scores and a moderately high correlation with ASES and SST outcomes. The PF-CAT takes significantly less time to complete and exhibits improved or similar floor and ceiling effects in comparison to IKDC, SST, and ASES scores. The PF-CAT can be used in evaluating sports medicine knee and shoulder patients.Level III, cross-sectional study.

With as many as 25% of patients reporting residual knee symptoms after primary total knee arthroplasty (TKA), alternative implant designs and surgical techniques have been proposed to further reduce these symptoms. There is growing evidence that retention of the anterior cruciate ligament (ACL) results in more natural knee kinematics; thus, implants with more normal joint mechanics could provide improved physical function postoperatively and reduce the amount of residual symptoms. Advancements in the bicruciate-retaining (BCR) TKA implant design have been made, and based on these, we wished to compare the BCR with a more traditional cruciate-retaining (CR) implant. (1) Was there a difference in the risk of reoperation after primary TKA between BCR and CR implant designs? (2) Was there a difference in the radiographic findings of radiolucent lines (RLLs) between the implant designs? (3) Was there a difference in patient-reported and clinical outcomes between the two implant designs? Between January 2013 and May 2014, two surgeons performed 475 primary TKAs. During this time, 78 (16%) of these were performed with BCR implants and 294 (62%) with CR implants; the remainder were performed with anterior-stabilized or more constrained designs as a result of increased deformity and/or ligamentous deficiencies. During this period, the general indications for BCR TKA were arthritic knees with only slight to moderate deformity and sufficient ligamentous integrity of both the ACL and posterior cruciate ligament. The indications for CR TKA were similar other than these patients presented with a deficient ACL. A total of 66 (85%) of the BCR and 237 (81%) of the CR TKAs were available for followup at a minimum of 12 months or when reoperation occurred before 12 months (mean, 18 months; range, 2–32 months). With the numbers available, there were no differences between the groups in terms of age and sex, but the patients undergoing CR TKA had a greater mean body mass index (33 ± 7 versus 31 ± 5 kg/m2, p = 0.032). The frequency of early reoperation was compared between the groups as were radiographic evidence of RLL, patient-reported outcomes, and knee range of motion (ROM). Knees in the BCR group had a higher frequency of all-cause revision (5% [three of 66] versus 1.3% [three of 237]; hazard ratio (HR), 7.44; 95% confidence interval [CI], 1.24–44.80; p = 0.028). Knees in the BCR group had a higher frequency of irrigation and debridement with component retention (HR, 0.07; 95% CI, 0.02–0.28; p < 0.001). No differences were found between groups for subsequent manipulation (HR, 0.34; 95% CI, 0.08–1.42; p = 0.137). The proportion of RLLs was greater in the BCR group (HR, 2.93; 95% CI, 1.62–5.32; p < 0.001) compared with the CR group. There were no differences between the groups in terms of the Physical Function Computerized Adaptive Test scores, Global10 scores or knee ROM outcomes. Preliminary short-term findings suggest the BCR implant has inferior survivorship and concerning radiographic findings when compared with a conventional CR implant with respect to complications after primary TKA. These findings raise concerns about the new BCR design; however, further randomized trials are necessary to determine superiority between alternative implant designs. Level III, therapeutic study.

Category: Ankle Arthritis, Hindfoot Introduction/Purpose: Triple arthrodesis is a commonly performed surgical treatment for hindfoot arthritis and deformity. No study has clearly delineated correlates of both clinical and radiographic outcomes in a sample size this large. The purpose of this study is to explore predictive and demographic outcome measures with long-term followup after triple arthrodesis. Methods: With IRB approval, an institutional radiology database was queried for patients undergoing triple arthrodesis between 2004 and 2016, by a single surgeon at a single institution. A total of 465 cases were identified. Pre- and post-operative clinical and radiographic data was collected retrospectively. Demographic and predictive data included: age, Body Mass Index (BMI), American Society of Anesthesiologists Score (ASA), Charleston Comorbidity Index (CCI), diabetic status, osteoporosis, hypothyroidism, and neuromuscular disease status. Clinical outcomes including infection rate, reoperation rate and clinical nonunion were recorded. Unintended return to the operating room defined clinical failure. Radiographic data including non-union rate, pre- and post- operative ankle degenerative joint disease was also recorded. Statistical analysis was then performed to evaluate the relationship between predictive measures and various outcomes including reoperation, infection, and non-union rates. 23 cases were lost to follow-up. Results: A total of 442 feet (397 patients) were analyzed. The average age was 54 years (14 to 85) with the majority of cases being female (60%). Average follow up was 593 days (40 to 4079). Overall failure rate was 13.7% with clinical nonunion rate of 4.5%. Infection rate was 5.9%. Mortality rate was 0% at 2 years post-operatively. Predictors of failure included: increased BMI, elevated ASA, history of diabetes, underlying neuromuscular disorder (Figure 1). We found no significant difference between pre and post-operative degenerative joint disease rates in the midfoot (9.4%, 12.5%) and ankle (11.7%,13.7%), respectively. Conclusion: Triple arthrodesis is a highly effective procedure for treating hindfoot arthritis. Certain predictive measures including BMI, ASA score, diabetic status and underlying neuromuscular disorders significantly correlate with radiographic union. Additionally, diabetic status significantly correlates with infection status postoperatively. An understanding of these predictive measures may help surgeons in their preoperative planning to improve their clinical and radiographic success rates.

Aims The Bundled Payments for Care Improvement (BPCI) initiative has identified pathways for improving the value of care. However, patient-specific modifiable and non-modifiable risk factors may increase costs beyond the target payment. We sought to identify risk factors for exceeding our institution’s target payment, the so-called ‘bundle busters’. Patients and Methods Using our data warehouse and Centers for Medicare and Medicaid Services (CMS) data we identified all 412 patients who underwent total joint arthroplasty and qualified for our institution’s BPCI model, between July 2015 and May 2017. Episodes where CMS payments exceeded the target payment were considered ‘busters’ (n = 123). Risk ratios (RRs) were calculated using a modified Poisson regression analysis. Results An increased risk of exceeding the target payment was significantly associated with increasing age (adjusted RR 1.04, 95% confidence interval (CI) 1.01 to 1.06) and body mass index (adjusted RR 1.03, 95% CI 1.003 to 1.06). Eight comorbid risk factors were also identified (all p < 0.05), only two of which were considered to be potentially modifiable (diabetes with complications and preoperative anaemia). An American Society of Anesthesiologist physical status classification system (ASA) score ≥ 3 (adjusted RR 2.3, 95% CI 1.67 to 3.18) and Charlson Comorbidity Index (CCI) ≥ 3 (adjusted RR 1.94, 95% CI 1.45 to 2.60) were risk factors for bundle busting. Conclusion Non-modifiable preoperative risk factors can increase costs and exceed the target payment. Future bundled payment models should incorporate the stratification of risk. Cite this article: Bone Joint J 2019;101-B(7 Supple C):64–69

Background In patients undergoing total joint arthroplasty (TJA), increasing attention has been directed recently toward identifying specific patient-related risk factors that may predispose patients to periprosthetic joint infection (PJI). Currently, it is unclear whether having a history of a treated native septic arthritis is a risk factor for PJI after TJA in the same joint. Previous studies have reported contradictory evidence and results varied between a substantially higher rates of PJIs to very low or no reported PJIs. Questions/purposes (1) What is the risk of PJI in patients who received TJA and had a history of treated same-joint native joint septic arthritis and (2) What are the associated risk factors for these patients developing PJI? Methods This was a multicenter retrospective analysis of patients who received primary THA or TKA between January 2000 and December 2016 and who had a history of treated native joint septic arthritis in the same joint. Patients were included in the study only if they were considered to have resolved their joint infection based on a preoperative evaluation that included: (1) the absence of clinical symptoms and signs of active infection or local joint inflammation, (2) recent plain radiographs showing only advanced degenerative changes without evidence of active osteolysis or bone infection, (3) preoperative laboratory investigations for infection, including erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and total leukocyte counts within normal ranges. Patients were reviewed for the occurrence of postoperative PJI. The final cohort included 62 patients who had a mean followup of 4.4 years (range, 3 months-17 years) from the time of TJA. A total of 21 patients (34%) had less than 2 years of followup, including six (10%) mortalities. In total, eight patients (13%) died during the study period, none of which were due to PJI. Patient characteristics, time interval from treatment of septic arthritis to TJA, and Charlson comorbidity index adjusted for age were collected. We used a Kaplan-Meier analysis to estimate the overall survivorship among all TJAs as well as those who underwent THA versus TKA, and we performed a statistical comparison using the Mantel-Cox log-rank test. We performed a Cox regression hazard ratio (HR) survival analysis to identify risk factors for PJI. The PJI odds ratios (OR) for patients who underwent TJA within 2 years of septic arthritis were calculated as an additional temporal analysis. Results In patients with a history of treated same-joint native septic arthritis, the proportion of PJI was five of 62 patients (8%). The Kaplan-Meier analysis demonstrated an overall survivorship free from PJI of 92% at 14.5 ± 1.14 years (95% confidence interval [CI] = 12.3-16.8 years). All PJI cases occurred only in patients who underwent TKA, which when analyzed separately, yielded a survivorship of 85% at 10.5 ± 0.9 years (95% CI = 8.7-12.3 years) versus 100% in patients who underwent THA (p = 0.068). Mean time to PJI occurrence was 10 months (range, 2-20 months). After controlling for relevant confounding variables, such as age, sex, affected joint and comorbidities, we found smoking (HR, 8.06; 95% CI, 1.33-48.67; p = 0.023) to be associated with increased risk for PJI development. Conclusion Patients with history of native joint infections are at higher risk of PJI, especially smokers. Despite our limitations, this study suggests careful assessment of several other factors in these patients, including allowing a minimum interval of 2 years from the time of resolving native joint septic arthritis to TJA. Patients who are undergoing TKA seem to be more prone to the PJI risk and may benefit from more aggressive planning. In addition, medical optimization of comorbidities that may confer additional risk, such as diabetes, become exceptionally important in these patients. Level of evidence Level III, therapeutic study.

Background Given the need for continued post-market surveillance, especially on novel implants, the present study attempts to determine the 3-year survivorship and patient-reported outcomes of a contemporary bicruciate-retaining total knee arthroplasty design, and to determine if a learning curve existed which could explain previously reported revision rates. Methods We performed a retrospective review on a consecutive series of 141 bicruciate-retaining total knee arthroplasties performed at our institution between May 2013 and October 2015. Thirty-four knees (19%) missing 2-year follow-up were excluded. Mean follow-up was 3 years (range 0.34-4.9). Patients who died (n = 5) or were revised prior to 2 years (n = 6) were included. A Kaplan-Meier analysis was used to evaluate revision-free survival. Results Survivorship at 3 years was 88% (82%-93%). Revisions were for isolated tibial loosening (5/19), anterior cruciate ligament (ACL) impingement (3/19), pain (4/19), unknown reasons (3/19), femoral and tibial loosening (2/19), ACL deficiency (1/19), and arthrofibrosis (1/19). The mean physical function computerized adaptive test T-score was 45 units (range 23-63). The mean T-scores for Patient-Reported Outcomes Measurement Information System Global measures were 49 (range 27-68) for physical health, 50 (range 28-68) for mental health, and a median 3 (interquartile range 1-8) on the numeric pain scale. Conclusion Revision-free survival of 88% at 3 years was lower than existing traditional TKA designs. The primary failure mechanisms were tibial loosening, ACL impingement, and pain. In the setting of higher than anticipated revision rates, despite patient-reported outcomes that are not different than seen in the general population, it is possible that further refinement in implant design or surgical technique may be needed prior to widespread use of this, or similar implant designs.

Background We sought to assess the prevalence of soft tissue changes seen on magnetic resonance imaging (MRI) after metal-on-metal (MOM) total hip arthroplasty (THA) and determine if the presence of pseudotumors was associated with metal ion levels, acetabular cup position, outcomes scores, and femoral head size. Methods After receiving an institutional review board exemption for secondary data analysis, we performed a cross-sectional study identifying 55 patients (55 hips) that underwent primary THA with a MOM articulation and had subsequent MRI imaging between February 2013 and February 2014 at a single academic medical center. Results Twenty-four patients (44%) had no evidence of pseudotumors, 27 (49%) had type I pseudotumors, and 4 (7%) were classified as having type II pseudotumors. The presence and severity of pseudotumors were associated with higher serum chromium levels ( P = .043). Neither acetabular inclination nor acetabular version was associated with the presence of pseudotumors, the severity of pseudotumors, or elevated serum metal ion levels (all P > .05). Increased metal ion levels were associated with lower Harris Hip Score and higher Harris Hip Score pain subscores (all P Conclusion In conclusion, pseudotumors on metal artifact reduction sequencing MRI may be present in both symptomatic and asymptomatic MOM THAs. Surgeons should therefore exercise caution in placing too much emphasis on isolated studies such as cross-sectional imaging. Instead, a structured approach to evaluation of MOM arthroplasty should be followed.

Abnormal anatomy frequently results in the use of a modular stem in patients undergoing primary total hip arthroplasty (THA) for developmental dysplasia of the hip (DDH). However, because these stems are not always available in the operating room, it would be helpful if standard radiographic views could be analyzed in such a way that patients whose femoral anatomy might call for stem modularity could be anticipated before surgery. To our knowledge, no such parameters have been defined. In the senior author’s practice, we used femoral neck anteversion of more than 25° as a determinant for use of a modular stem. Given this criterion, we asked if we could reliably identify plain film radiographic parameters of the femur that predict the use of modular stems. We looked at the following: (1) the neck-shaft angle based on the anteroposterior (AP) radiograph (alpha); (2) the neck-shaft angle from the crosstable lateral radiograph (beta); and (3) the calculated femoral anteversion angle. We reviewed preoperative radiographs from 50 of 67 patients (79 hips) who had a primary diagnosis of DDH and underwent primary THA from January 1999 to February 2007 inclusive. Hips with prior femoral-sided surgery (n = 2) or without preoperative films (n = 19) were excluded. Furthermore, patients with bilateral hips had the second hip excluded (n = 8). Twenty-one of 50 received a modular femoral stem based on the criterion of intraoperative neck-shaft anteversion of greater than 25° as measured by the senior surgeon (CLP), whereas the remainder received tapered nonmodular stems. There were no differences in age, sex, height, or weight between the modular stem group and tapered stem group. Radiographs were evaluated to record the parameters listed. Patients in whom modular femoral stems were used had a greater mean AP (alpha) neck-shaft angle compared with patients who received tapered nonmodular stem (152°; 95% confidence interval [CI], 146°–157° versus 137°; 95% CI, 134°–141°; p < 0.001) with an optimal cutoff point for determining the use of modular stems of ≥ 142° (receiver operating characteristic [ROC] area = 73%). Hips in which modular femoral stems were chosen had a smaller mean lateral (beta) neck-shaft angle (152°; 95% CI, 148°–157° versus 161°; 95% CI, 158°–164°; p = 0.003) with an optimal cutoff point of ≤ 153° (ROC area = 65%). Hips in which modular femoral stems were used had a higher femoral anteversion angle (mean 45°; 95% CI, 37°–54° versus 21°; interquartile range, 17°–25°; p < 0.001) with an optimal cutoff of ≥ 32° (ROC area = 80%). Preoperative radiographs anticipated the use of modular stems during THA for DDH in a practice where modular stems were chosen on the basis of a neck-shaft angle of greater than 25° measured at surgery. We found that this could be predicted on preoperative radiographs based on smaller lateral neck-shaft angles, steeper AP radiographic neck-shaft angles, and increased femoral anteversion calculated using these angles. Prospective studies are needed to better determine if these cutoff values adequately predict the use of modular stems.