TKA is More Durable Than UKA for Morbidly Obese Patients: A Two-Year Minimum Follow-Up Study.

BACKGROUND: Unicompartmental knee arthroplasty (UKA) indications have expanded during the past two decades to include some morbidly obese patients (body mass index (BMI) > 40 kg/m2). Few published studies have compared UKA and total knee arthroplasty (TKA) in this unique patient subgroup with conflicting observations. METHODS: We retrospectively compared 89 mobile bearing UKA (71 patients) and 201 TKA (175 patients) performed at a single institution with a minimum 2-year follow-up (mean 3.4 years). Demographic characteristics were similar for both patient cohorts. A detailed medical record review was performed to assess the frequency of component revision, revision indications, minor secondary procedures (components retained), and infections. RESULTS: UKA was more frequently associated with clinical failure (29.2% vs 2.5%, P < .001) and component revision (15.7% vs 2.5%, P < .001), TKA was more frequently associated with extensor mechanism complications or knee manipulation (5.5% vs 0.0%, P = .02), and there was no difference in the infection rate (3.0% vs 2.2%, P = 1.0). CONCLUSION: Early complications were lower following UKA but were outweighed by higher component revision rates for arthritis progression and implant failure. The study findings suggest that TKA provides a more predictable mid-term outcome for morbidly obese patients considering knee arthroplasty surgery.

High Failure Rates for Unicompartmental Knee Arthroplasty in Morbidly Obese Patients: A Two-Year Minimum Follow-Up Study.

BACKGROUND: Several recent studies have recommended offering unicompartmental knee arthroplasty (UKA) to all patients regardless of body mass index (BMI). The aim of this investigation was to evaluate the proposition that UKA can indeed be offered to the morbidly-obese and super-obese (morbidly-obese, BMI ≥ 40 kg/m2) without compromising results or survivorship. METHODS: We retrospectively reviewed mobile-bearing medial UKA procedures performed at our facility from January 2012 to May 2015 with a minimum of 2-year follow-up. The study cohort was divided into patients with morbid obesity (BMI ≥ 40 kg/m2) and those without morbid obesity (BMI < 40 kg/m2). A detailed medical record review was performed. Extracted outcome data included the frequency of (1) major revision procedures (components revised), (2) minor secondary procedures (components not revised), (3) infection procedures, and (4) recommendations for revision. RESULTS: We found 152 patients (190 knees) who met criteria for inclusion. Mean follow-up duration was 3.4 years (range: 2.0-6.8 years). Major revision surgery occurred more frequently in the morbid-obesity UKA group (15.7% vs 3.0%, P < .01). Rates of minor secondary surgery and infection were comparable for both groups. Most failures in the morbid-obesity UKA group (85.7%) were due to disease progression involving other compartments or mobile-bearing instability. CONCLUSION: We found the rate of early major revision surgery in morbidly-obese patients undergoing UKA to be over 5-times greater than that of other patients. Failure was predominantly due to disease progression in other compartments or mobile-bearing instability. Further study is warranted and needed before expanding UKA indications to the morbidly-obese population.

Arthroplasty Rates Not Increasing in Young Patients With Rheumatoid Arthritis: A National Database Review, 2005 Versus 2014.

BACKGROUND: For 20 years, authors have predicted an expansion in total knee arthroplasty (TKA) and total hip arthroplasty (THA) utilization. Over this same period, the introduction of biological disease-modifying antirheumatic drugs has dramatically altered the treatment of rheumatoid arthritis (RA) with hopes of preventing articular damage and obviating the need for prosthetic replacement. The goal of our investigation was to evaluate TKA and THA utilization in young patients with RA (<65 years) in 2005 vs 2014 compared to patients with osteoarthritis (OA). METHODS: Using relevant International Classification of Disease Ninth Revision (ICD-9) and Current Procedural Terminology codes, the Truven MarketScan Database (over 46 million enrollees) was queried to determine THA and TKA incidence rates for RA and OA patients aged <65 years during the final decade of ICD-9 use. Patients with potentially confounding ICD-9 codes were excluded to limit coding variation. Statistical analysis consisted of student t-tests, Pearson's chi-square tests, and Breslow-Day tests. RESULTS: For patients with OA, TKAs increased substantially from 0.07% in 2005 to 0.1% in 2014 (+42.9% change, P < .001). Similarly for patients with OA, THAs increased from 0.04% to 0.06% over the same time period (+66.0% change, P < .001). For young patients with RA, the rate of TKA remained relatively stable-1.06% in 2005 to 1.04% in 2014 (-1.7% change, P = .65)-as did THA-0.44% to 0.48% (+9.0% change, P = .14). CONCLUSIONS: Dramatic increases in THA and TKA rates for OA patients aged <65 years were indeed observed from 2005 to 2014. This trend, however, was not seen in the RA population where TKA and THA rates remained unchanged.

Patients, pictures, and privacy: managing clinical photographs in the smartphone era.

It is easy to capture and share clinical photographs and x-ray images using modern smartphones. This technology affords health-care providers the ability to rapidly collaborate and facilitate care for their patients. This improvement, however, has increased concerns regarding patient privacy and the safeguarding of protected health information. Health-care providers should understand the deidentification process for patient photographs because this process fundamentally changes the expectations and requirements for how providers are to handle this information. Properly deidentified patient photographs (and other data) are no longer considered identifiable protected health information and are not subject to the handling requirements mandated by the Health Insurance Portability and Accountability Act. This article addresses patient privacy concerns attendant to the acquisition, transmission, and sharing of clinical photographs among health-care providers. It provides guidelines for providers seeking to minimize the risk of noncompliance with privacy requirements as they adopt these new technologies into their practices.

Femoral Component Malrotation Produces Quadriceps Weakness and Impaired Ambulatory Function following Total Knee Arthroplasty: Results of a Forward-Dynamic Computer Model.

Proper placement of the prosthetic components is believed to be an important factor in successful total knee arthroplasty (TKA). Implant positioning errors have been associated with postoperative pain, suboptimal function, and inferior patient-reported outcome measures. The purpose of this study was to investigate the biomechanical effects of femoral component malrotation on quadriceps function and normal ambulation. For the investigation, publicly available data were used to create a validated forward-dynamic, patient-specific computer model. The incorporated data included medical imaging, gait laboratory measurements, knee loading information, electromyographic data, strength testing, and information from the surgical procedure. The ideal femoral component rotation was set to the surgical transepicondylar axis and walking simulations were subsequently performed with increasing degrees of internal and external rotation of the femoral component. The muscle force outputs were then recorded for the quadriceps musculature as a whole, as well as for the individual constituent muscles. The quadriceps work requirements during walking were then calculated for the different rotational simulations. The highest forces generated by the quadriceps were seen during single-limb stance phase as increasing degrees of femoral internal rotation produced proportional increases in quadriceps force requirements. The individual muscles of the quadriceps displayed different sensitivities to the rotational variations introduced into the simulations with the vastus lateralis showing the greatest changes with rotational positioning. Increasing degrees of internal rotation of femoral component were also seen to demand increasing quadriceps work to support normal ambulation. In conclusion, internal malrotation of the femoral component during TKA produces a mechanically disadvantaged state which is characterized by greater required quadriceps forces (especially the vastus lateralis) and greater quadriceps work to support normal ambulation.

Articulating spacers for the treatment of infected total knee arthroplasty: effect of antibiotic combinations and concentrations.

Performing 2-stage procedures using articulating antibiotic cement spacers to eradicate infection while providing pain relief and maintaining function has become common among many surgeons. Despite the efficacy of antibiotic cement spacers in the treatment of infected total knee arthroplasty, questions remain regarding the dosing of the antibiotic cement. The authors assessed their experience with different antibiotic regimens and concentrations for the eradication of infection. Sixty-nine infected total knee arthroplasties with an average follow up of 31 months (range, 6-70 months) treated with articulating antibiotic spacers were retrospectively reviewed. Treatment groups were divided according to spacer antibiotic agents used and the amount of antibiotics added to the cement. Low-dose spacers were defined as those incorporating less than 4 g of antibiotic per 40-g bag of cement, and high-dose spacers were defined as those incorporating 4 g or more of antibiotic per 40-g bag of cement. High- vs low-dose spacers using a single or multiple antibiotic agents were compared. The overall rate of infection eradication was 88%. Dose dependency was not detected for spacers that incorporated single or multiple antibiotic agents, and multiple-agent spacers produced comparable success rates despite more frequent use in patients with impaired immune function. Further study of optimal combinations and concentrations of antibiotic agents incorporated into these spacers is needed to help minimize treatment failures while maximizing treatment efficacy.

Metacarpal neck fractures: results of treatment with traction reduction and cast immobilization.

Although fractures of the fifth metacarpal neck (boxer's fractures) are common, their treatment can be problematic. A description of a technique utilizing traction reduction is presented in this paper. The records and radiographs of 59 patients who underwent reduction using longitudinal traction and subsequent immobilization in a specially molded cast were retrospectively reviewed. On average, 80% of initial fracture angulation in the sagittal plane was corrected, and only 1 degrees of this correction was lost at the discontinuation of casting (3-4 weeks). We have found this technique to be highly effective in the treatment of boxer's fractures. Advantages of this treatment include its efficacy, ease, and improved patient tolerance over other casting techniques.