Community-based Heel Ultrasound Screening Leads to Osteoporosis Follow-up and Treatment Recommendations

“Providing calcaneal quantitative ultrasound (US) scanning as a free screening can be an effective strategy for improving osteoporosis detection and treatment,” says Edward Fox, M.D., Penn State Hershey Bone and Joint Institute. In a recent study of adults who received free calcaneal US screening at community health fairs and telephone follow-up, Fox, Frances Tepolt, M.D., and Susan Hassenbein, CCRP, demonstrated that nearly half of those identified as high-risk for osteoporosis (T-score less than or equal to -1) sought evaluation from a health care professional within three months. The large majority of these individuals also received recommendations for further bone density evaluation and treatment (Figure).

Heel Ultrasound ScreeningParticipants, none of which had ever had a fragility fracture, were also given access to informational pamphlets about bone health and osteoporosis. Fox emphasizes, “This study is among the first to examine individuals, access to osteoporosis screening results and disease information, prior to the occurrence of any overt signs of disease, like a fragility fracture. With about half of the high-risk individuals seeking follow-up, this study supports that heel US screening has the potential to increase osteoporosis diagnosis and intervention.” Continue reading

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Pigment Epithelium Derived Factor (PEDF) Influences Matrix Mineralization: Implications for Osteogenesis Imperfecta and Beyond

Patients with type VI Osteogenesis Imperfecta (OI) have mutations in the serpfin1 gene that lead to an absence of pigment epithelium derived factor (PEDF) production, and experience bone defects and frequent fracturing. A series of in vitro experiments performed by Feng Li, M.D., Ph.D., instructor, Penn State Hershey Orthopaedics and Rehabilitation, under the guidance of Christopher Niyibizi, Ph.D., are among the first to demonstrate a direct link between PEDF and a broad array of gene expression changes associated with increased osteoblast differentiation and matrix mineralization (Figure 1). The findings, recently published in Stem Cells¹ and Journal of Cellular Physiology², help to explain why patients with this rare subtype of OI experience bone fractures despite normal type 1 collagen expression and formation. The implications of the findings, however, extend to other conditions marked by decreased mineralization, like osteoporosis.

Osteogenesis Imperfecta (OI)

FIGURE 1. PEDF increases mineral deposition by mineralizing osteoblasts and suppresses sclerostin production by osteocytes. A) Osteoblasts were cultured in osteogenic medium in presence or absence of exogenous PEDF for twenty-one days. Analysis of mineral deposition by Alizarin red S staining (AR-S) showed increased mineral deposition in cultures supplemented with PEDF. B) Sclerostin production by osteocytes in mineralizing cultures was detected beginning at two weeks, and cultures supplemented with exogenous PEDF reduced production of sclerostin by osteocytes.

For the experiments, exogenous PEDF was added to the osteogenic culture medium of adult human mesenchymal stem cells, PEDF enhanced the cells’ differentiation and increased mineralization in vitro¹. According to Niyibizi, “Among the more pronounced effects of exogenous PEDF were the 70 to 75 percent reductions in sclerostin and matrix extracellular phosphoglycoprotein expression (MEPE) by osteocytes².” Sclerostin is a strong inhibitor of bone formation and MEPE inhibits matrix mineralization; with addition of PEDF to the mineralizing medium, matrix mineralization significantly increased, compared to cultures without exogenous PEDF. Continue reading

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Choosing Between Total Hip Arthroplasty and Hemiarthroplasty for Femoral Neck Fractures: Patient Selection is the Key

Q: Is there a general consensus among orthopaedic surgeons about how best to choose between total hip arthroplasty (THA) versus hemiarthroplasty for their patients with femoral neck fractures?

Davis: No. There are conflicting opinions about which of these procedures is best suited to particular patients. Studies from individual centers tend to emphasize the improved functional outcomes in patients who have a THA, while national registry data tends to demonstrate the lower complication rate with hemiarthroplasty. The differences may relate to the patient populations in each study and the technical skills of the surgeons. Outcomes from each type of study are valuable. Surgeons and patients should balance the risks and benefits to determine the best approach for each individual patient.

Q: Based on your interpretation of the available registry data, what are the main advantages and disadvantages of THA?

Davis: Compared to hemiarthroplasty, THA yields better pain relief and patients are able to walk farther, on average. Disadvantages, however, include longer surgical time, increased dislocation risk, and potential for acetabular component loosening. Several countries have registry data that suggest rates of complications, including dislocation, are higher with THA versus hemiarthroplasty. Also in most hip fracture cases, the acetabular bone stock is softer and the acetabular fixation is less secure than in arthritic hips with denser bone. In my opinion, the literature supports THA as the procedure of choice for younger more active patients and those with pre-existing arthritis. (Figure 1)

Total Hip Arthroplasty (THA)

FIGURE 1A: Patient with femoral neck fracture for THA. FIGURE 1B: Patient X-ray after surgery. FIGURE 2: Appropriate candidate for hemiarthroplasty; 64-year-old man who fell on ice.

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Limitations for Headless Compression Screws in Distal Interphalangeal Arthrodesis in Patients, Especially Women, with Small Fingers

Headless Compression Screws

LEFT: A well-placed and appropriately
sized headless compression screw in a
female patient.
RIGHT: An oversized and slightly dorsal
placed screw has cut out of the dorsal
cortex of the distal phalanx in this female,
putting her at risk of fingernail injury and
nonunion.

Arthrodesis of distal interphalangeal (DIP) joints using headless compression screws for internal fixation is often used to relieve arthritis-related pain, instability, and deformity. New findings highlight important limitations in the broad use of this hardware in female patients and others with smaller bones. In women, 65 percent of small fingers and approximately 25 percent of women’s index and ring finger distal phalanges were too small to safely accommodate the 2.8 millimeter trailing thread diameter of commonly used commercially available cannulated compression screws.1 By contrast, less than 8 percent of male distal phalanges were too small for such screws. The findings are based on analysis of distal phalanges height and width from digital radiographs of 200 hands from 200 patients at Penn State Hershey Bone and Joint Institute.1

The lead investigator, Michael Darowish, M.D., explains, “Achieving DIP arthrodesis safely with headless compression screws in patients with smaller bones, particularly women, has been a concern, but the true extent of the issue wasn’t objectively investigated until now. That more than half of all female patients undergoing DIP arthrodesis may be affected is probably much greater than most surgeons would have guessed.”

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Management of a Complex Open Pelvic Injury: A Coordinated Team Approach

A man in his forties was brought to the Penn State Hershey Medical Center trauma unit. The patient sustained an open pelvic fracture, as well as an irreducible hip dislocation; he had a significant injury to his lower intestinal tract and massive soft tissue loss.

“Open pelvic fractures have a mortality rate of 50 percent. If you combine this with the spectrum of additional injuries this patient presented with, that number is probably closer to 75 percent,” says Henry Boateng, M.D., an orthopaedic trauma surgeon with Penn State Hershey Bone and Joint Institute. A team of trauma, colorectal, orthopaedic, and plastic surgeons joined together to improve the odds for this patient. “For cases like this, we take a very aggressive approach, and prioritize the treatments needed. The goal in the early stages is to prevent infection and provide stability,” explains Boateng. The abdomen was emergently addressed, the hip was emergently reduced, and the pelvis was then stabilized. Continue reading

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Superior Labral Tears in Patients Older Than 40: What is the Best Treatment?

Intraoperative arthroscopic image of an acute, traumatic SLAP tear.

Intraoperative arthroscopic image of an acute, traumatic SLAP tear.

Superior labrum anterior-posterior (SLAP) repair in young athletes has a well-established record of success, marked by relief of pain, improved range of motion, and return to normal levels of activity. Over the past ten years, however, there has been a remarkable five-fold increase in SLAP repairs in older patients. According to Aman Dhawan, M.D., Penn State Hershey Bone and Joint Institute, “Recently there’s been a lot of controversy about performing arthroscopic SLAP repair in patients older than 40 years of age. I often see these older patients experience SLAP repair-related complications.” The SLAP repair literature is marked by conflicting reports, some showing very good outcomes and others describing poor outcomes in older patients. Continue reading

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Sarcopenia and Increased Body Fat in Sclerostin-deficient Mice: Interactions between Muscle and Bone and Potential Implications for Osteoporosis Management

In the absence of mechanical load (off-loading), as may occur following injury, bone and muscle tissue are lost, increasing the risk of low-impact bone fracture and musculoskeletal weakness and injury. Henry J. Donahue, Ph.D., Michael and Myrtle Baker Professor of Orthopaedics at Penn State College of Medicine, observes, “While bone loss following disuse is fairly well-understood, relatively little is known about how bone and muscle tissues interact during off-loading.”

Sclerostin [a glycoprotein encoded by the SOST gene that inhibits the Wnt signaling pathway], a key factor that mediates bone loss, exhibits increased expression by osteocytes during off-loading and inhibits bone formation by osteoblasts. Donahue, and anatomy graduate student Andrew Krause, along with Charles Lang, Ph.D., distinguished professor of cellular and molecular physiology, conducted an experiment in SOST-knockout mice, globally deficient in sclerostin, and subjected to off-loading, to examine effects on muscle tissue, as well as bone. Donahue explains, “In the SOST-knockout mice, as we predicted, trabecular bone loss from two weeks of off-loading was largely mitigated, compared to the loss seen in wild-type mice. What was interesting and unexpected was that at baseline, even though both groups of mice were of similar weight, the sclerostin-deficient mice had significantly less lean muscle tissue and more adipose tissue; off-loading led to further and dramatic loss of muscle [e.g., sarcopenia] and gain of fat.” (see figure)

Osteoporosis Management

Sclerostin-deficient mice (right) have bigger bone than normal wild type mice (left). However, muscle mass actually decreases in sclerostin-deficient mice.

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