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Acoustic technique developed to detect knee osteoarthritis

A revolutionary medical technique using sound waves to identify osteoarthritis in the knee has been developed by researchers.

The UK is leading this new field of health research based on listening to the sounds emitted by the body.

Microphones are attached to the knees of patients, and the high frequency sound waves emanating from their knees are measured as they stand up. These acoustic emissions are interpreted by computer software to give information about the health of the patient's knee.

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Pacira Pharmaceuticals Inc. announces new data on the use of EXPAREL to treat postsurgical pain following total knee arthroplasty

Pacira Pharmaceuticals, Inc. has announced results of an independent, physician-initiated study designed to evaluate the difference in postsurgical pain and opioid consumption between patients who received EXPAREL versus a multi-drug analgesic cocktail for pain management following total knee arthroplasty (TKA). The data, presented at the annual meeting of the American Association of Hip and Knee Surgeons (AAHKS), found that patients treated with EXPAREL reported significantly lower patient-perceived pain scores and morphine sulfate equivalence consumption, and reported higher satisfaction with pain control and overall experience, compared with patients who received the multi-drug analgesic cocktail.

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No functional differences found between short-, straight-stem THA implants

Recently published study data indicated short-stem and straight-stem implants for total hip arthroplasty exhibited no significant differences in functional outcome measures.

Researchers conducted a randomized, double-blinded study of 80 patients who underwent total hip arthroplasty (THA). Patients were grouped by whether their THA utilized a short-stem or conventional straight-stem implant. Radiological and functional outcomes were evaluated at 6 weeks postoperatively, and quality of life was quantified via Harris Hip Score, SF-36 and WOMAC scores.

No significant changes in offset differences were observed in either group from before surgery to after surgery. At final follow-up, no significant differences between groups were found in Harris Hip Score, SF-36 or WOMAC values, according to the researchers.

Comparison of long-term survival rates among both cohorts will help determine whether short stems are a viable alternative THA solution, the researchers concluded.

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Chronic kidney disease increases prosthetic joint infection rates after TJA

Patients with stage 1, 2 or 3 chronic kidney disease may have a higher rate of prosthetic joint injection after total joint arthroplasty, according to study results.

Researchers retrospectively reviewed electronic medical records for 377 patients with stage 1 to 2 kidney disease with 402 patients who had stage 3 chronic kidney disease. All patients underwent total hip arthroplasty (THA) or total knee arthroplasty (TKA) between 2004 and 2011.

Patients with stage 3 chronic kidney disease had a greater rate of overall mortality compared with patients with stage 1 to 2 chronic kidney disease, according to the researchers.

When adjusted for comorbid disease, the researchers found no significant increases in joint infection, readmission or early revision between patients with stage 1 to 2 chronic kidney disease compared with patients with stage 3 chronic kidney disease.

Compared with patients with end-stage renal disease, dialysis and kidney transplant, overall incidence of infection was high but much less in chronic kidney disease patients.

In a subgroup analysis, the significant difference in mortality rate persisted between the stage 1 to 2 group vs. the stage 3 group in patients who had undergone THA, but not in patients who had undergone TKA, according to the researchers. 
Study results showed a slightly lower rate of 90-day readmission in patients with stage 1 to 2 chronic kidney disease who underwent TKA than in patients with stage 3 chronic kidney disease, whereas 90-day readmission was slightly higher in the THA subgroup.

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Higher baseline expectations for TJR improved health-related quality of life, satisfaction

Health-related quality of life and satisfaction improved among patients who had higher expectations for total joint replacement at baseline compared with patients who had lower expectations, according to study results.

Researchers recruited 892 patients preparing for total joint replacement (TJR) of the knee or hip due to primary osteoarthritis. Before surgery and for 12 months afterward, patients completed questionnaires with five questions about expectations before surgery; an item to measure satisfaction; WOMAC and SF-12; and questions about sociodemographic information. The researchers performed general linear models and logistic regression analysis to determine the association of patients’ expectations at baseline with satisfaction and changes in health-related quality of life (HRQoL) 12 months after surgery.

Study results showed larger improvements in HRQoL at 12 months among patients who had higher pain relief or ability to walk expectations. WOMAC and SF-12 physical component summary domains also improved more among patients with high expectations regarding the ability to walk, interact with other and psychological wellbeing expectations, according to the researchers.
Patients with very high expectations on the SF-12 physical component summary regarding their ability to walk and with high or very high pain relief expectations on SF-12 mental component summary experienced better improvement compared with patients with low expectations, the researchers found.

The researchers also found patients who had high or very high daily activities expectations were more likely to be satisfied.

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Older patients still fastest-growing demographic for TKA

Despite total knee arthroplasty becoming more prevalent in patients younger than 65 years of age, the main demographic of growth is still among patients older than 65, according to recent study data.

Researchers compared 1999 to 2008 U.S. census data for individuals 18 to 44 years old, 45 to 64 years old, and 65 years and older and the number of total knee arthroplasties (TKAs) performed annually in each age group. Per-capita incidence rates were calculated, and the growth rate in all demographics was determined.

Approximately 305,000 TKAs were performed beyond the number predicted by population growth alone in 2008. Patients older than 65 years of age represented the largest growing cohort, as 151,000 recorded TKA procedures and a per-capita growth rate from 5.2 to 9.1 procedures per 1,000 individuals was observed. Per-capita growth rate also increased from 1.4 to 3.3 procedures per 1,000 individuals among patients 45 to 64 years old.

TKAs were found to have increased 234% during the span of this study, from 264,000 in 1999 and approximately 616,000 in 2008, with fewer than 48,000 of the additional procedures able to be explained by population increase, according to the researchers.

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TKA provides excellent outcomes after lower-extremity amputation

Although total knee arthroplasty is rare after lower-extremity amputation, it can provide excellent functional and clinical outcomes, according to study results.

Researchers reviewed 13 primary total knee arthroplasties (TKAs) in 12 patients with prior lower-extremity amputation, among which 12 TKAs were performed on the contralateral side of the amputated limb and one was performed on the ipsilateral side. Using clinical examinations and patient surveys, the researchers calculated preoperative and postoperative Knee Society scores. The study’s primary endpoint was failure, which was defined as revision for any reason. Average clinical follow-up occurred at 6.8 years.

The researchers observed improvement in Knee Society scores from 30.4 preoperatively to 88.5 following TKA with a prior contralateral amputation.

At final follow-up, radiographic evidence of aseptic loosening of the tibial components was observed in 23.1% of patients, and the researchers recommended augmentation of tibial fixation with a stem during TKA after contralateral amputation.

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Regular physical activity improved patient satisfaction after TKA

Patients who participated in regular physical activity after undergoing total knee arthroplasty experienced improved satisfaction with their outcomes, according to study results.

Researchers evaluated physical activity profiles of 369 patients before and after total knee arthroplasty (TKA) using a questionnaire that contained the University of California — Los Angeles activity scale and types of sports activities. Using subgroup comparisons and partial correlation analyses, the researchers assessed the associations of socio-demographic features and postoperative functional outcomes with the physical activity levels, as well as the effects of regular physical activity on patient satisfaction with replaced knees.

Both before and after TKA, study results showed the three most common sports activities were walking, swimming and bicycling. Although the mean activity level remained similar after TKA, the frequency of moderate activity levels and moderate types of physical activities increased, according to the researchers.

The researchers also found higher postoperative activity levels reported by patients with higher postoperative function scores. However, socio-demographic factors were not associated with activity level. Overall, greater patient satisfaction was associated with regular physical activity.

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Regional anesthesia for hip fracture surgery was not associated with increased 30 day mortality compared to general anesthesia

A hip fracture can mean surgery and a hospital stay. The type of anesthesia used in that surgery might affect the length of the hospital stay and recovery. Researchers compared the two types of surgical anesthesia in hip fracture patients and found that there was no difference in survival a month after surgery. Patients who had regional anesthesia had a slightly shorter hospital stay.

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Prior TKR or revision THR causes increased periprosthetic fractures

Periprosthetic fractures are especially common in patients with prior total knee replacement or revision total hip replacement a decade after primary total hip replacement, according to study results.

Researchers identified 58,521 Medicare beneficiaries who had elective primary total hip replacement (THR) for non-fracture diagnoses between July 1995 and June 1996 and followed them using Medicare Part A claims data through 2008. Using ICD-9 codes, researchers identified periprosthetic femoral fractures occurring from 2006 to 2008. The incidence density method was used to calculate the annual incidence of periprosthetic femoral fractures, and Cox proportional hazards models were used to identify risk factors for periprosthetic fracture. The risk of hospitalization during the subsequent year was also calculated.

Overall, 55% of patients who had elective primary THR between July 1995 and June 1996 survived until January 2006, with 0.7% of these patients developing a periprosthetic femoral fracture between 2006 and 2008. The researchers found an annual incidence of periprosthetic fractures of 26 per 10,000 person-years among these individuals.

According to Cox proportional hazards models, patients had a greater risk of periprosthetic fracture after having a total knee replacement or a revision total hip replacement between the primary THR and 2006. The researchers found a three-fold higher risk of hospitalization in the subsequent year among THR patients who sustained periprosthetic femoral fracture compared with patients without fractures.

“These data will help clinicians as they portray to patients and their families the long-term concerns associated with living with a hip implant,” the researchers wrote. “The message is that periprosthetic fractures are relatively rare, though more frequent in patients with multiple implants. Further, these fractures are typically associated with the need for considerable subsequent medical care, as they are accompanied by a much greater risk hospitalization in the subsequent year than experienced by THR recipients who did not have hip fracture.”

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