Postoperative ileus in the lower extremity arthroplasty patient.

Postoperative ileus is a recognized complication of lower extremity surgery. In a review of 21,589 patients who underwent either total hip or total knee arthroplasty between 1988 and 1997, 0.32% developed postoperative ileus. The ileus lasted >3 days in 46% of patients. The purpose of this study was to investigate the risk factors associated with ileus during 3 days after total joint arthroplasty. The average age of the patients with prolonged ileus was 69.1 years, and 70% were male. The development of a prolonged ileus was associated significantly with younger age (P<.005) and male gender (P<.02). In total knee arthroplasty, more cases of postoperative ileus were seen in bilateral surgery. Patients who are younger, male, and undergoing bilateral total knee arthroplasty are at an increased risk of having a more prolonged postoperative ileus and should be monitored closely.

In-line skating injuries.

In-line skating has remained a popular recreational activity all over the world. The number of injuries seemingly reached a plateau in the late 1990s. However, there are still more injuries caused by in-line skating than from skateboarding, hockey or lacrosse and rugby. In 1997, the estimated annual cost of medical treatment for these injuries in the US was over $US4 billion. Adolescence still represents the largest group of skaters, both in participation and injury. Although 10- to 14-year-olds account for 60% of injuries, in 1996 the US Consumer Product Safety Commission reported nearly 1500 injuries in individuals 65 years and over. Risk factors for injury include inexperience, aggressive skating and amount of time spent skating. There are also more recent data to suggest that self-reported expert skaters are more likely to sustain an injury. Reluctance to use personal protective equipment (PPE) by in-line skaters remains high. The general consensus is that PPE is effective in reducing the incidence and severity of in-line skating injuries. Therefore, efforts should be made to increase awareness of risk factors for injury in all skaters; to increase use of safety equipment; to provide safe environments for skating; and to legislate skating laws that will protect skaters from injuries.

Determining femoral rotational alignment in total knee arthroplasty: reliability of techniques.

Several anatomic axes routinely are used for determining femoral rotational alignment in total knee arthroplasty. The purpose of this study was to determine the reliability of these techniques. The transepicondylar axis, anteroposterior axis, and balanced flexion gap tension line were identified relative to the posterior condylar axis in 8 fresh frozen cadaver knees by 3 independent observers. The flexion-extension axis was defined in each knee for comparison. The anteroposterior and balanced tension axes defined most reliably the flexion-extension axis and best balanced the flexion gap with no significant interobserver differences. The transepicondylar axis was less predictable and significantly more externally rotated than the anteroposterior axis (P < .005) and the balanced tension line (P < .00001). Flexion gap tensioning may offer superior reliability because of its independence of obscured or distorted bone landmarks.

Anatomy, histologic features, and vascularity of the adult acetabular labrum.

Acetabular labrum tears have been implicated as a cause of hip pain in adult patients. Few studies describe the anatomy, histologic features, and microvasculature of the acetabular labrum and labral tears. Fifty-five embalmed and 12 fresh-frozen adult hips with a mean age of 78 years (range, 61-98 years) were studied. Of these, 96 % (53 of 55) of the hips had labral tears, with 74% of the tears located in the anterosuperior quadrant. Histologically, the fibrocartilaginous labrum was contiguous with the acetabular articular cartilage through a 1- to 2-mm zone of transition. A consistent projection of bone extends from the bony acetabulum into the substance of the labrum that is attached via a zone of calcified cartilage with a well-defined tidemark. Two distinct types of tears of the labrum were identified histologically. The first consisted of a detachment of the fibrocartilaginous labrum from the articular hyaline cartilage at the transition zone. The second consisted of one or more cleavage planes of variable depth within the substance of the labrum. Both types of labral tears were associated with increased microvessel formation seen within the tear. The acetabular labrum tear appears to be an acquired condition that is highly prevalent in aging adult hips. Labral tears occur early in the arthritic process of the hip and may be one of the causes of degenerative hip disease.

Contribution of acetabular labrum to articulating surface area and femoral head coverage in adult hip joints: an anatomic study in cadavera.

The purpose of our study was to describe the gross anatomy of the adult acetabular labrum and to determine its contribution to the depth, surface area, and volume of the acetabulum. Fifty-five embalmed hips were studied. Each hip was disarticulated, and standardized measurements were taken. Calculations of the acetabular articulating surface area and volume, with and without the labrum, were performed based on these measurements. Average width of the acetabular labrum was 5.3 mm (SD, 2.6 mm). The labrum was wider anteriorly and superiorly than posteriorly. The surface area of the acetabulum without the labrum was 28.8 cm2; with the labrum, it was 36.8 cm2 (P < .0001). The volume of the acetabulum without the labrum was 31.5 cm3; with the labrum, it was 41.1 cm3 (P < .0001). There was no side-to-side difference in contribution of the labrum to either surface area or volume between right and left hips. Comparison of these indices for males and females showed statistically significant differences in absolute but not relative increases.

Well-leg compartment pressures during hemilithotomy position for fracture fixation.

OBJECTIVE: To evaluate the relationship between the well-leg compartment pressures and time during hemilithotomy position for fracture fixation. DESIGN: Prospective. SETTING: Level 1 trauma center. PATIENTS/PARTICIPANTS: Ten patients who underwent intramedullary nailing of a fractured femur in the hemilithotomy position (with a well-leg holder). INTERVENTION: Continuous pressure monitoring was achieved with in-dwelling slit catheters inserted into the calf compartments of the well leg. Baseline measurements were obtained in the supine position. After the leg was placed in the hemilithotomy position, compartment pressures were monitored throughout surgery. MAIN OUTCOME MEASUREMENTS: Calf compartment pressures at baseline, during hemilithotomy position, and post-hemilithotomy were compared. The association between body mass index and compartment pressure was analyzed. RESULTS: A consistent pattern was observed between compartment pressures and time. The curve was that of a step function in which the pressure increased as soon as the leg was placed in the well-leg holder and remained elevated until the leg was taken down. The pressure jumped from a baseline of 9.2 to 27.3 millimeters of mercury (mm Hg) (p<0.0001). While in the hemilithotomy position, the leg pressure trended slightly upward. Once the leg was taken down, the pressure immediately returned to a near-baseline level of 8.1 mm Hg (p<0.0001). A significant correlation was also found between the body mass index and leg pressure (R2 = 0.713; F = 0.002). CONCLUSIONS: The use of the well-leg holder to maintain hemilithotomy position increases the calf compartment pressures dramatically and significantly. Therefore, we recommend avoiding this position for fracture fixation in at-risk patients.

Total knee arthroplasty for steroid-induced osteonecrosis.

There have been only a few reports that evaluate the outcome of total knee arthroplasty in patients with steroid-induced osteonecrosis of the knee. We retrospectively reviewed 31 total knee arthroplasties in 24 patients with confirmed steroid-induced osteonecrosis of the knee. The average follow-up was 64 months. Of surviving knees, 92% had significant improvement in knee scores. Five knees (16%) required a revision procedure. Reasons for revision were aseptic loosening in 3 knees and sepsis in 2 knees. Complications not requiring revision occurred in 6 of 31 knees (19%). Survivorship of total knee arthroplasty to revision in patients with steroid-induced avascular necrosis of the knee was 84% at 5 years. Although there was a slightly higher complication rate, this may, in part, be due to the severity of the patients' underlying disease processes. Total knee arthroplasty can be a successful procedure for chronically ill patients with steroid-induced osteonecrosis.

Predictors of injury among adult recreational in-line skaters: a multicity study.

OBJECTIVES: This study examined risk factors for injury, injury prevalence, safety gear use, and skating habits of adult recreational in-line skaters. METHODS: Randomly selected in-line skaters in 6 major US cities were interviewed. RESULTS: Only 6% of skaters consistently wore all 4 recommended types of safety gear. Skaters with greater skating experience were more likely to perform tricks, wear less safety gear, and sustain an injury. CONCLUSION: More experienced adult recreational in-line skaters are at increased risk for injury. Safety gear use in alarmingly low in adult recreational in-line skaters, especially experienced skaters. Safe skating education programs should consider targeting this newly recognized at-risk skating population.

The increased level of PDGF-A contributes to the increased proliferation induced by mechanical stimulation in osteoblastic cells.

Mechanical stimulation can prompt healing of bone fractures. However, it is largely unknown how osteogenesis is promoted by mechanical stimulation. In this study, we found that mechanical strain-induced proliferation of osteoblastic cells (MC3T3-E1) accompanied increased levels of platelet-derived growth factor-A (PDGF-A) mRNA, determined by quantitative reverse transcription/polymerase chain reaction. In addition, neomycin and W-7, which blocked mechanical strain-induced proliferation of the osteoblast cells, also blocked mechanical stimulation-induced elevation of PDGF-A mRNA. Finally, an antibody against PDGF can inhibit physical stimulation-induced proliferation of MC3T3-E1 cells, suggesting that the increased MC3T3-E1 cells produced by mechanical stimulation at least partially depends on the increased activity of PDGF.

Electrical stimulation induces the level of TGF-beta1 mRNA in osteoblastic cells by a mechanism involving calcium/calmodulin pathway.

It is well-known that electrical stimulation can prompt healing of bone fractures. However, the mechanism involved is less clear. In this study, we found that capacitively coupled electric field-induced proliferation of osteoblastic cells (MC3T3-E1) accompanied increased levels of transforming growth factor-beta 1 (TGF-beta1) mRNA determined by quantitative reverse transcription/polymerase chain reaction. Previous reports have shown that verapamil and W-7, both of which block voltage gated calcium channels and inhibit the activation of cytosolic calmodulin, respectively, blocked capacitively coupled electric field-induced proliferation of the osteoblast cells. Interestingly, we found that verapamil and W-7 can also block capacitively coupled electric field-induced elevation of TGF-beta1 mRNA. This result suggested that electrical stimulation induces the level of TGF-beta1 mRNA in osteoblastic cells by a mechanism involving calcium/calmodulin pathway. The potential roles of TGF-beta in the electrical signal-induced osteogenesis was discussed.