Severe lower extremity trauma often results in the loss of bone, muscle, and skin. Reconstruction of these injuries is extremely challenging due to the amount of bone that must be reconstructed and the size of wounds that must be closed. Wound coverage is usually achieved with the use of a microvascular free flap procedure performed by plastic surgeons. In this technique, healthy tissue is brought to the damaged region and attached to the local blood vessels to allow it to live and grow. Restoration of the lost bone can be accomplished with repeated massive bone grafting, but this is often unreliable.
J. Spence Reid, M.D., Penn State Hershey Bone and Joint Institute explains, “The Ilizarov technique, coupled with the recently developed Taylor spatial frame offers an alternative approach, that while labor intensive, is very reliable and precise in restoring missing bone.” This technique was pioneered by the Soviet orthopaedic surgeon, Gavriil Abramovich Ilizarov and employs a circular external fixation frame (figure A) with percutaneous wires and pins attached to metal rings to move bone segments from the outside of the skin. The Taylor spatial frame is a refinement of the original frame and differs from the original in that the rings are connected by six angled struts that are adjusted by the patient. The daily position of each strut is determined by the use of a computer program providing accuracy down to one millimeter.
Among the nearly 8 million fractures that occur annually in the United States, approximately 10 percent of these, or 800,000 show impaired healing or non-union. According to J. Spence Reid, M.D., Penn State Hershey Bone and Joint Institute, “Although we know that certain factors like smoking and diabetes, and some medications are associated with impaired bone healing; in some cases it’s unexplained. Impaired fracture healing, regardless of the cause, is expensive to treat and significantly delays the patient’s return to normal activities. Because Penn State Hershey is a tertiary referral center, we frequently see this problem in our clinic. In many cases, patients with delayed healing will require a bone graft and revision of fixation hardware at the fracture site.”
Reid and his colleagues have begun to study the possibility that genetic factors predispose certain patients to poor bone healing. In an exploratory study conducted at Penn State Milton S. Hershey Medical Center, bucomocosal tissue samples were obtained from patients with normal healing fractures of the tibia, femur, humerus, or forearm and a matching group of patients with similar fractures that showed impaired healing. Tissue sample DNA was genotyped for 144 single nucleotide polymorphisms (SNPs) the researchers considered potentially involved in bone healing. The presence of each SNP was then tested for an association with fracture nonunion. Preliminary data from this study were presented at the 2012 annual meeting of the Orthopedic Research Society1 and is currently being reviewed for publication. “The initial data from our small exploratory study have been very encouraging. In particular, significant associations between impaired bone healing and SNPs related to bone morphogenetic protein, type 7 (BMP7) and inducible nitric oxide synthase (iNOS) have been found,” notes Reid. Continue reading
Charles M. Davis, III, M.D., Ph.D.
Infection of a total arthroplasty is a serious complication that typically requires complex treatment of the infection and frequently revision surgery. Charles Davis, III, M.D, Ph.D., Penn State Hershey Bone and Joint Institute, says, “Infection is highly suspected in any patient with a recent total joint arthroplasty, when the site continues to drain for more than seven days post-operatively, as well as in a patient with a long-standing arthroplasty that shows a pattern of recurrent drainage, or with a sudden onset of severe joint pain, swelling, redness, and heat.” As the chief of hip and knee joint arthroplasty, Davis sees many suspected cases of total joint arthroplasty infections. “Management of patients with infections is difficult for both the physician and the patient. Treating the infection, placement of a new device, and postoperative recovery may take six to twelve months.”
The heavy disease burden of this problem has led Davis and his team to launch an aggressive protocol aimed at prevention. An infectious disease specialist, Crystal Zalonis, D.O., has been central in planning and implementing all preventive and infection treatment efforts. We focus on preoperative, intraoperative, and postoperative measures to prevent infection. Perioperative preventive steps focus on optimizing blood glucose levels and reducing bacterial carriage. “One key to minimizing infection risk is maintaining tight blood glucose control. In diabetic patients, if preoperative hemoglobin A1c (HbA1c) is more than seven, we defer surgery for a time, until better glucose control is achieved. In the acute postoperative period, blood glucose levels are monitored for all total arthroplasty patients, diabetic and non-diabetic alike. Blood glucose levels are carefully managed for all patients after surgery,” explains Davis. Continue reading
Showing contracture and post-aponeurotomy of a patient who has been able to resume full activity.
Duputyren’s contracture, a genetically-influenced disease marked by overgrowth of fascia in the palm and fingers, can lead to markedly diminished hand function. Currently there is no cure; even with open surgery, contracture can recur. A nonsurgical approach toward Duputyren’s contracture, needle aponeurotomy, is gaining acceptance as a low-risk, low cost treatment strategy. Michael Darowish, M.D., Penn State Hershey Bone and Joint Institute, trained at the Cleveland Clinic with Avrum Froimson, M.D., a leading expert in aponeurotomy. Darowish explains, “Aponeurotomy is performed in the clinic. I use a fine, 25-gauge needle inserted under the skin. This is swept back and forth to divide the collagen cords that cause finger contracture. I begin distally, injecting a small amount of lidocaine into the skin over the cord, then inserting the needle and dividing the cord. This is repeated at a number of sites, proceeding proximally toward the palm. A small amount of kenalog is injected at the conclusion to soften any remaining nodules.” Continue reading
Club foot is a congenital deformity that, if left untreated, can cause lifelong disability. William L. Hennrikus, M.D., explains, “Club foot is relatively common, affecting about one of every 1,000 newborns and occurs more often in boys. Siblings are also at higher risk (about four in 100).” The deformity involves the bones, blood vessels, muscles, and tendons of the lower leg (see figure A) and is linked to genetic and environmental factors. Infants with club foot can have other conditions, such as spina bifida or arthrogryposis. Continue reading
With the prevalence of osteoporosis expected to rise in the coming years, early recognition and management of bisphosphonate-related atypical femur fractures will become increasingly important. Edward J. Fox, M.D., explains, “In many cases, osteoporosis is treated with long-term bisphosphonate therapy, which suppresses osteoclastmediated bone turnover. With prolonged bisphosphonate use (more than five years), some patients (about one in 1,000) develop atypical femur fractures.” Atypical femur fractures are stress fractures that usually occur in the proximal one-third of the diaphyseal bone, but can occur more distally, too; beginning in the lateral cortex and gradually progressing medially (see figure below).
Fox adds, “With atypical fractures, a small ‘beak’ of bone forms on the lateral femur surface and this is where the fracture begins.” This contrasts with more typical stress fractures that occur in the medial portion of bone and progress laterally. “Clinically, when a patient with osteoporosis presents complaining of thigh and hip pain that’s unrelated to any acute injury, I always ask about history of bisphosphonate treatment. It’s important to obtain X-rays not only of the hip joint but also the femur shaft; otherwise the problem may go undetected or misdiagnosed,” advises Fox. In most cases, conservative treatment is effective. Continue reading
Solution: an elegantly “simple” biomimetic film coating.
Critical-size bone defects are challenging to bridge and successfully treat. A research team at Penn State Hershey Bone and Joint Institute, led by Henry J. Donahue, Ph.D., postdoctoral fellow Alayna Loiselle, Ph.D., and Akhlesh Lakhtakia, Ph.D., the Charles Godfrey Binder Professor of Engineering Science and Mechanics, Pennsylvania State University, is exploring new biotechnologies to enhance bone integration in such patients. Donahue explains, “While traditionally used allographic bone implants can be effective for bridging critical-size defects, patients encounter postoperative complications, such as ongoing pain, increased risk of bone fracture and infection at the implant site, and need for additional surgeries. Allograft bone often is not well integrated into host tissue and lacks the strength of native bone.”
Part of the problem seems to arise from the processing of cadaveric bone, which removes all host cells and disease particles prior to implantation. While helping to ensure safety, the process, however, destroys the naturally rough, nanotopographic features of the bone’s outer surface, rendering it less steoconductive, thus hindering cell migration to the repair site and discouraging osteoblast differentiation. Continue reading