Faculty Bibliography

BACKGROUND:Periprosthetic joint infection following total knee arthroplasty (TKA) is a serious complication often related to obesity which leads to poor patient outcomes and increased resource utilization. A periarticular soft tissue index (PASTI) may help predict postoperative wound complications than BMI alone. METHODS:Three hundred seventy-six TKA patients with a preoperative, lateral knee X-ray radiograph and 1 year of follow up were analyzed. We used 2 pairs of soft tissue and bony measurements, one referencing the femur and the other the tibia. A high PASTI was defined as a ratio >3.0. Minor complications involved clinical interventions related to the surgical wound. Major complications involved return to the operating room. RESULTS:More minor complications occurred in high PASTI for both tibial (20.9% vs 6.4%; odds ratio 3.89, 95% confidence interval 1.94-7.79, P < .001) and femoral measurements (15.3% vs 7.2%; odds ratio 2.09, 95% confidence interval 1.06-4.15, P = .013). Major complications were also more frequent in high PASTI, though not statistically significant. The proportion of obesity (BMI > 30) in both minor (12.4% vs 7.7%, P = .140) and major complications (2.8% vs 3.3%, P = .788) was not statistically different. CONCLUSION/CONCLUSIONS:More wound complications occurred in patients with high PASTI, while no difference was seen using BMI. BMI has traditionally approximated patient size, but does not describe variations in body habitus. PASTI is a more reliable and direct way to assess the periarticular soft tissue envelope size, which is associated with postoperative wound complications in the knee.

BACKGROUND:At our institution, all postoperative total hip arthroplasty (THA) candidates have received home health services (HHS), consisting of visiting nurses, physical and occupational therapists. However, with a more technologically inclined patient population, electronic patient rehabilitation applications (EPRAs) can be used to deliver perioperative care at the comfort of the patient's home. The aim of this study is to investigate the clinical utility and economic burden associated with digital rehabilitation applications in primary THA recipients. METHODS:We conducted a single-center, retrospective review of patients operated between November 2016 and November 2017. Before surgery, and at the discretion of the surgeon, patients were assigned to EPRA with HHS or EPRA alone. Patient baseline demographics, EPRA engagement, and validated patient-reported outcomes (PROs) were (Veterans Rand 12-Item Health Survey [VR-12] and Hip Disability and Osteoarthritis Outcome Score Junior) at baseline and 12 weeks. These PRO scores were correlated with cohort assignments to assess noninferiority of EPRA alone. RESULTS:In total, 268 patients received either EPRA-HHS (n = 169) or EPRA (n = 99) alone. Patients receiving EPRA only were on average younger (60.8 vs 65.8; P < .0001), but otherwise similar to patients in the EPRA-HHS cohort. EPRA-only patients demonstrated no differences in VR-12 (P > .05) and Hip Disability and Osteoarthritis Outcome Score Junior (P > .05) when compared with EPRA-HHS. CONCLUSION/CONCLUSIONS:The integration of electronic rehabilitation tools is gaining acceptance within the orthopedic community. Our study demonstrated that EPRA alone was clinically noninferior while substantially less costly than EPRA-HHS.

BACKGROUND:Some patients have mid-flexion instability despite stability at 0° and 90° of flexion. This study aims to determine the effects of total knee arthroplasty (TKA) stability while changing femur implant size and position. METHODS:A computational analysis was performed simulating knee flexion of posterior stabilized (PS) and cruciate retaining (CR) TKA designs. Deviations from the ideal TKA implant position were simulated by adjusting tibiofemoral proximal-distal position and femur anterior-posterior position as well as implant size. Forces in ligaments connecting the femur and tibia were collected. Total tibiofemoral ligament load for mid-knee flexion of 15°-75° was analyzed vs proximal-distal implant position, implant size, implant design, and knee flexion for PS and CR knees. Posterior cruciate ligament load was also analyzed for CR knees. RESULTS:Total tibiofemoral ligament load was significantly reduced by a more proximal tibiofemoral and anterior femur position (P < .001). Implant size did not have a significant effect on tibiofemoral ligament load (P > .1). Implant design and knee flexion significantly influenced total tibiofemoral ligament load (P < .001), but the interactions with implant proximal-distal position were not significant (P > .2), indicating that implant proximal-distal position had a similar effect across the 15°-75° knee flexion range for both studied PS and CR implant designs. CONCLUSION/CONCLUSIONS:PS and CR TKA can be well-balanced at 0° and 90° knee flexion and have instability in mid-flexion. Elevating the joint line and shifting the femur anteriorly can cause the knee to be too loose in mid-flexion.

Obesity is an epidemic in the health care system. Obesity poses several challenges and raises unique issues for the arthroplasty surgeon. Obese patients are at higher risk for infection and dislocation. Additionally, obese patients have poorer implant survivorship and functional scores postoperatively. Obesity is a modifiable risk factor and weight loss preoperatively should be strongly considered. Obese patients must be counseled so that they have realistic expectations after total joint arthroplasty.

Although bariatric surgery is a proven means of weight loss and treatment of obesity-related comorbidities in morbidly obese patients, it is not yet clear how it affects outcomes after total joint arthroplasty in this high-risk patient population. This article explores the effects of obesity and bariatric surgery on osteoarthritis and total joint arthroplasty, and also discusses the financial and ethical implications of use of bariatric surgery for risk reduction before total joint arthroplasty.

BACKGROUND:Irrigation and debridement (I&D) is performed for early management of periprosthetic joint infection (PJI) following total knee arthroplasty (TKA). Symptom reporting is a subjective measure and may miss direct management of PJI. Utilizing an objective time interval from index procedure to I&D may better inform treatment decisions. METHODS:From 2009 to 2017, retrospective review was performed of 55 knee PJI cases at our institution. All patients underwent polyethylene liner exchange and I&D for PJI. Patients were stratified by time from index procedure to I&D (≤2 weeks, >2 weeks). Success was defined as eradication of infection and resolution of presenting symptoms. Failed cases required subsequent procedures due to infection. RESULTS:Average follow-up time after index TKA was 2.5 years. Among patients with I&D within 2 weeks of index TXA, 14 patients (82%) were successfully treated while 3 (18%) had infection recurrence. These outcomes were significantly improved compared to patients with I&D after 2 weeks: 19 (50%) successes and 19 (50%) failures (P = .024). Staphylococcal species were the most frequent pathogen in patients treated before and after 2 weeks of index TKA (39% and 50%, respectively). Outcomes were pathogen-independent in PJIs treated before or after 2 weeks of index TKA (P = .206 and .594, respectively). CONCLUSION/CONCLUSIONS:Our results demonstrate that patients with early PJI managed with I&D and liner exchange within 2 weeks of index TKA had higher rates of treatment success when compared to those with I&D beyond 2 weeks. These findings suggest that time from index TKA to I&D is an objective and reliable indicator of treatment success when considering I&D in acute onset knee PJI.

Background/UNASSIGNED:Underweight patients undergoing total hip arthroplasty have been largely overlooked. The purpose of this study was to evaluate their complications profiles compared to normal weight individuals. Methods/UNASSIGNED:Patients were selected from the NSQIP database, matched, and arranged into 2 groups based on BMI. Complications were recorded and analyzed to determine differences in outcomes. Results/UNASSIGNED:Multivariate analysis demonstrated increased length of hospital stay (LOS) (p = 0.006) for underweight patients but failed to demonstrate higher rates of medical or surgical complications. Conclusion/UNASSIGNED:There are no increased rates of infectious or medical complications in underweight patients undergoing THA. However, increased LOS was demonstrated.

PURPOSE/OBJECTIVE:To assess changes in the patterns of T2 and T1rho values within grade 1 cartilage lesions of osteoarthritis (OA) patients compared to healthy controls. MATERIALS AND METHODS/METHODS:Twenty healthy knees and 25 OA knees were examined on a 3 T scanner. Areas of signal heterogeneity within the cartilage of the distal femur were identified using fat suppressed proton density-weighted imagines. T2 and T1rho values in each OA patient with grade 1 lesions were compared to average T2 and T1rho values of the corresponding areas in healthy subjects. RESULTS:A total of 28 areas including grade 1 lesion were identified. Compared to normal cartilage, the majority of grade 1 cartilage lesions demonstrated either no significant change or a statistically significant increase in both T2 values (18/28, 64%) and T1rho values (23/28, 82%). Compared to T2, T1rho demonstrated a greater proportion of statistically significantly higher values in OA patients than those from the normal controls. However, T2 and T1rho values in grade 1 lesions can be decreased, or demonstrate mixed patterns compared to those in healthy cartilage. CONCLUSION/CONCLUSIONS:Our results suggest that early degenerative cartilage lesions can demonstrate various patterns of T2 and T1rho changes.

BACKGROUND: Bariatric surgery is frequently recommended prior to total joint arthroplasty (TJA) for morbidly obese patients with end-stage arthropathy. Current published data on the efficacy of bariatric surgery for preoperative medical optimization has yielded mixed results, and the effect of time from bariatric surgery to TJA on the preoperative risk profile is not well defined. Our study evaluated the effect of time from bariatric surgery to TJA on 90-day complication and readmission rates. METHODS: We utilized the Healthcare Cost and Utilization Project (HCUP) California State Inpatient Database (SID) to identify patients who underwent TJA following bariatric surgery between 2007 and 2011. Primary endpoints were 90-day complication rates and all-cause 90-day readmission rates following TJA. RESULTS: We identified 330 cases of bariatric surgery followed by total hip arthroplasty (THA) and 1017 cases followed by total knee arthroplasty (TKA). There were no significant demographic differences among patients who underwent TJA greater than or less than 6 months after bariatric surgery. Patients undergoing THA more than 6 months after bariatric surgery were significantly less likely to be readmitted within 90 days for any cause. There was no association between time from bariatric surgery to THA or TKA and 90-day complications. DISCUSSION: Delaying THA at least 6 months after bariatric surgery may help reduce the rate of 90-day readmissions in this high-risk patient population. Arthroplasty surgeons recommending bariatric surgery as preoperative risk modification should consider the patient's overall nutritional status, medical comorbidities, and overall response to surgery prior to booking for TJA.

CASE/METHODS:We review the case of a 44-year-old man with Camurati-Engelmann disease, who presented with chronic right hip pain that did not improve following intra-articular hip injections. He was functionally debilitated because of the worsening pain. Routine radiographs demonstrated severe right hip osteoarthritis and severe diaphyseal sclerosis of the femur. To address the narrowed medullary cavity, appropriate reaming of the diaphysis and broaching to fill the metaphysis were performed. The patient underwent an uncemented total hip arthroplasty that resulted in an excellent recovery with no complications. CONCLUSION/CONCLUSIONS:Uncemented total hip arthroplasty serves as a good option for patients with hip osteoarthritis secondary to Camurati-Engelmann disease. Anticipation of potential operative challenges is the key to avoiding complications and achieving an optimal, durable outcome.