The emu, a large bipedal bird with hip joint biomechanics similar to humans, was used to establish an experimental model of femoral head osteonecrosis and subsequent femoral head collapse. Focal lesions were induced in 20 adult male emus using an alternating liquid nitrogen freezing and radiofrequency heating insult. At 2, 4, 8, 12 and 16 weeks post-surgery, hip magnetic resonance imaging (MRI) was performed. Before the emus were sacrificed, barium sulphate was infused to the lower extremity to study blood vessel distribution patterns. Femoral samples were scanned by micro-computed tomography (micro-CT) and evaluated histologically. Hip MRI showed changes from broad oedema to femoral head collapse. Emus developed a crippled gait from post-operative week 6. Micro-CT scans and histology showed human-like osteonecrotic changes with an impaired local blood supply. The protocol resulted in consistent full-range osteonecrosis of the femoral head that may serve as a model for testing potential treatments.
LaverniaCJSierraRJGriecoFR: Osteonecrosis of the femoral head. J Am Acad Orthop Surg1999; 7: 250–261.
2.
MontMAJonesLCEinhornTA: Osteonecrosis of the femoral head. Potential treatment with growth and differentiation factors. Clin Orthop Relat Res1998; 355 (suppl): S314–S335.
3.
MontMARajadhyakshaADHungerfordDS: Outcomes of limited femoral resurfacing arthroplasty compared with total hip arthroplasty for osteonecrosis of the femoral head. J Arthroplasty2001; 16 (8 suppl 1): 134–139.
4.
NichCSarialiel-HHannoucheD: Long-term results of alumina-on-alumina hip arthroplasty for osteonecrosis. Clin Orthop Relat Res2003; 417: 102–111.
5.
YuanBLiuZ: Treatment of osteonecrosis of the femoral head: Combination of operation and multiple cellular mediators. Med Hypotheses2007; 68: 502–505.
6.
MalizosKNKarantanasAHVaritimidisSE: Osteonecrosis of the femoral head: Etiology, imaging and treatment. Eur J Radiol2007; 63: 16–28.
7.
TroyKLBrownTDConzemiusMG: Contact stress distributions on the femoral head of the emu (Dromaius novaehollandiae). J Biomech2009; 42: 2495–2500.
8.
QinLZhangGShengH: Multiple bioimaging modalities in evaluation of an experimental osteonecrosis induced by a combination of lipopolysaccharide and methylprednisolone. Bone2006; 39: 863–871.
9.
ZhangGShengHHeYX: Continuous occurrence of both insufficient neovascularization and elevated vascular permeability in rabbit proximal femur during inadequate repair of steroid-associated osteonecrotic lesions. Arthritis Rheum2009; 60: 2966–2977.
10.
ConzemiusMGBrownTDZhangY: A new animal model of femoral head osteonecrosis: One that progresses to human-like mechanical failure. J Orthop Res2002; 20: 303–309.
11.
ReedKLBrownTDConzemiusMG: Focal cryogen insults for inducing segmental osteonecrosis: Computational and experimental assessments of thermal fields. J Biomech2003; 36: 1317–1326.
12.
MartelJBuenoADominguezMP: Percutaneous radiofrequency ablation: Relationship between different probe types and procedure time on length and extent of osteonecrosis in dog long bones. Skeletal Radiol2008; 37: 147–152.
13.
LeTXAndrewsRT: Thermal osteonecrosis of the rib after radiofrequency ablation in the thorax. J Vasc Interv Radiol2008; 19: 940–944.
14.
EncaladaIRichmondJC: Osteonecrosis after arthroscopic meniscectomy using radiofrequency. Arthroscopy2004; 20: 632–636.
15.
CetikOCiftHComertB: Risk of osteonecrosis of the femoral condyle after arthroscopic chondroplasty using radiofrequency: A prospective clinical series. Knee Surg Sports Traumatol Arthrosc2009; 17: 24–29.
16.
BonuttiPMSeylerTMDelanoisRE: Osteonecrosis of the knee after laser or radiofrequency-assisted arthroscopy: Treatment with minimally invasive knee arthroplasty. J Bone Joint Surg Am2006; 88 (suppl 3): 69–75.
17.
GageAMMontesMGageAA: Destruction of hepatic and splenic tissue by freezing and heating. Cryobiology1982; 19: 172–179.
18.
SunJZhangAXuL: Evaluation of alternate cooling and heating for tumor treatment. Int J Heat Mass Transfer2008; 51: 5478–5485.
19.
SunJLuoXZhangA: A new thermal system for tumor treatment. Conf Proc IEEE Eng Med Biol Soc2005; 1: 474–477.
20.
OhzonoKTakaokaKSaitoS: Intraosseous arterial architecture in nontraumatic avascular necrosis of the femoral head. Microangiographic and histologic study. Clin Orthop Relat Res1992; 277: 79–88.
21.
TroyKLLundbergHJConzemiusMG: Habitual hip joint activity level of the penned emu (Dromaius novaehollandie). Iowa Orthop J2007; 27: 17–23.
22.
BayBKHamelAJOlsonSA: Statically equivalent load and support conditions produce different hip joint contact pressures and periacetabular strains. J Biomech1997; 30: 193–196.
23.
ChenCCLinCLChenWC: Vascularized iliac bone-grafting for osteonecrosis with segmental collapse of the femoral head. J Bone Joint Surg Am2009; 91: 2390–2394.
24.
PlenkHJrGstettnerMGrossschmidtK: Magnetic resonance imaging and histology of repair in femoral head osteonecrosis. Clin Orthop Relat Res2001; 386: 42–53.
25.
MontMAEinhornTASponsellerPD: The trapdoor procedure using autogenous cortical and cancellous bone grafts for osteonecrosis of the femoral head. J Bone Joint Surg Br1998; 80: 56–62.
26.
LiYHanRGengC: A new osteonecrosis animal model of the femoral head induced by microwave heating and repaired with tissue engineered bone. Int Orthop2009; 33: 573–580.
27.
HoffmannNEBischofJC: The cryobiology of cryosurgical injury. Urology2002; 60 (2 suppl 1): 40–49.
28.
HofferFADawNCXiongX: A phase 1/pilot study of radiofrequency ablation for the treatment of recurrent pediatric solid tumors. Cancer2009; 115: 1328–1337.
29.
FarrellMACharboneauWJDiMarcoDS: Imaging-guided radiofrequency ablation of solid renal tumors. AJR Am J Roentgenol2003; 180: 1509–1513.
30.
MirzaANFornageBDSneigeN: Radiofrequency ablation of solid tumors. Cancer J2001; 7: 95–102.
31.
HamazoeRMaetaMMurakamiA: Heating efficiency of radiofrequency capacitive hyperthermia for treatment of deep-seated tumors in the peritoneal cavity. J Surg Oncol1991; 48: 176–179.
32.
Hines-PeraltaAHollanderCYSolazzoS: Hybrid radiofrequency and cryoablation device: Preliminary results in an animal model. J Vasc Interv Radiol2004; 15: 1111–1120.
33.
LiuTZhouYYuT: Minimally invasive probe system capable of performing both cryosurgery and hyperthermia treatment on target tumor in deep tissues. Minim Invasive Ther Allied Technol2004; 13: 47–57.
34.
LafforgueP: Pathophysiology and natural history of avascular necrosis of bone. Joint Bone Spine2006; 73: 500–507.
