Purpose: Identification of novel therapeutics to accelerate acute fracture healing remains critical. A prostaglandin EP-2 receptor agonist (CP-533,536) has demonstrated acceleration of fracture healing in preclinical models.

Method: In a phase II randomized, blinded, placebo-controlled trial the efficacy of a single local injection of three doses of CP-533,536 (0.5mg, 1.5mg and 15mg) was compared to both placebo and a standard of care arm in patients with closed tibial shaft fractures treated with reamed inter-locked intramedullary nails. Patients were followed at two week intervals to six months with a final evaluation at one year. Fracture healing was independently adjudicated by a radiologist panel and an orthopedic surgeon panel.

Results: Ninety-nine patients were enrolled ranging in age from 17–76 years. Baseline characteristics were comparable across treatment groups. No statistically significant differences in median healing time between any of the CP-533,536 treatment groups and placebo were observed based on radiology panel assessment, however significant differences were demonstrated by an orthopedic panel. At weeks eight, 10, 12, 14 and 16 a higher percentage of subjects in the CP-533,536 1.5 and 0.5 mg groups were considered healed compared to the placebo and the 15 mg groups by the orthopedic panel assessment. Moreover, the CP-533,536 – 0.5 mg group showed a statistically higher (p≤0.05) mean radiographic healing score than placebo treated group at weeks eight, 14, 16, 18, and 24.

Conclusion: CP-533,536 demonstrated accelerated healing in patients with acute tibia fractures by an orthopedic panel. Confirmatory trials are required to assure validity of the observed treatment effects.

Antegrade femoral nailing through the greater trochanter, using nails designed for piriformis entry, is associated with varus and iatrogenic comminution. Nails designed for greater trochanter insertion theoretically reduce these complications, but clinical outcomes comparing these to piriformis entry remain unknown. We compared femoral shaft fracture repair with a nail designed for trochanteric entry to an identical nail without a trochanteric bend inserted through the piriformis fossa.

The trochanteric nail was easier to insert with decreased operative and fluoroscopy time. It resulted in equally high union rates, low complication rates, and functional results similar to conventional nailing through the piriformis fossa.

Trochanteric antegrade nailing of the femur is thought to be advantageous over conventional antegrade nailing due to improved ease of insertion, but is unproven. This study compares results of femoral shaft fracture treatment using a nail designed specifically for trochanteric entry, Trigen TAN, to results using an identical nail without a trochanteric bend inserted through the piriformis fossa, Trigen FAN.

A femoral nail specially designed for trochanteric insertion resulted in equally high union rates, equally low complication rates, and functional results similar to conventional antegrade femoral nailing through the piriformis fossa. As a result of increased ease of insertion, decreased operative time and decreased fluoroscopy time, the greater trochanter entry portal, coupled with an appropriately designed nail, represents a rational alternative for antegrade femoral nailing.

Insertion of a specially designed femoral nail though the trochanter is faster, easier, and requires less fluoroscopy time than conventional antegrade nailing through the piriformis fossa.

Overall, there was < 10° malalignment and no iatrogenic fracture comminution. The average operative time was 21% greater using the FAN nail than using the TAN nail, (p=.08). The average fluoroscopy time was 61% greater for the FAN group than for the TAN group, (p< .05). Trends in functional outcome (Lower Extremity Measure) were similar for both groups.

One hundred and eight patients treated for a femoral shaft fracture were included in this study. Ninety-eight patients were treated with either a Trigen TAN nail (n=38) or Trigen FAN nail (n=53); seventeen patients with insufficient follow-up were excluded from analysis.

Funding:Smith & Nephew, Memphis TN

Reducing exposure to radiation is a concern to physicians and supporting staff. Little is known about the factors leading to increased exposure in intramedullary nailing of long bone fractures. This study examines antegrade and retrograde nailing of femur and tibia fractures. Factors that increased radiation exposure were obesity, severely comminuted fractures, nails inserted through the piriformis fossa, and insertion of more locking bolts in femoral nails. In addition, femoral nails required more radiation exposure than tibial nails.

Exposure to radiation is a concern to physicians. The purpose of this study was to determine factors associated with increased radiation exposure with intramedullary nailing of long bone fractures.

Femoral nailing through the piriformis fossa, highly comminuted fractures, insertion of more locking bolts (femur), and obesity are each associated with the higher radiation exposure.

Factors associated with increased radiation exposure are identified for tibial and femoral nailing.

Radiation exposure was higher for nailing of femur fractures (ninety-two seconds) compared to nailing of tibia fractures (sixty seconds). Exposure was greatest for insertion through the piriformis fossa (one hundred and twenty-one seconds) and least for retrograde insertion (seventy-four seconds) and intermediate for insertion through the trochanter (eighty-seven seconds). Obese patients (BMI > 30) had higher exposure times for both femoral (obese-one hundred and sixty seconds, non-obese-eighty-five seconds) and tibial nailing (obese-seventy-nine seconds, non-obese-fifty-five seconds). Only the most severely comminuted fracture patterns (Winquist IV) were associated with increased fluoroscopy time. Increasing number of interlocking bolts was associated with higher exposure for the femur but not the tibia.

One hundred and thirty-nine consecutive patients treated with intramedullary nailing for either a femoral shaft (OTA 32, n=71) or tibial shaft (OTA 42, n=68) fracture were prospectively evaluated in this IRB approved study. Radiation exposure (c-arm fluoroscopy time) was measured. Femur fractures were treated with either a retrograde nail (n=24), an antegrade nail inserted through the piriformis fossa (n=20), or an antegrade nail inserted through the tip of the greater trochanter (n=27).

Funding: Smith & Nephew