Emerging Hipsters James Webley, MD, FACEP

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1 Hip dislocations Posterior Hip Dislocation 85% of hip dislocations High energy injuries MVA most common mechanism Symptoms Pain hip or thigh Short leg Flexion of hip Internal rotation Adduction Numbness posterior thigh possible Emerging Hipsters James Webley, MD, FACEP X-rays Look carefully for fracture of the femoral neck The dislocated hip has the ligamentum teres torn and, thus, the foveal artery. Further it is thought the femoral head is squishing the capsular arteries or stretching them or perhaps kinking them. As such, undoing this situation will help restore some of the blood flow to the femoral head that is believed to be ischemic while dislocated. Avascular necrosis occurs in 2-10% of cases if the hip is reduced within 6 hours. The rate of AVN increases to 50% as time passes. Treatment Urgent reduction with ortho consult if possible. Multiple techniques are possible. It is perhaps easiest to use those techniques that allow the surgeon to use their lower extremity muscle groups. Adequate anesthesia is the key to any hip reduction. Emergency OR if the hip is not reducible or if the sciatic nerve is trapped by the reduction. Anterior Inferior Hip Dislocation 10% of hip dislocations Mechanism Abduction Extension Hip flexion

2 Striking the dashboard in an MVA with the abducted knee is a typical mechanism of injury. Physical exam Large external rotation Flexion Abduction Short Reduction is urgent for the same reasons that it is in posterior dislocations. The only significant difference in the technique is that the femoral head must be disengaged from the obturator foramen with lateral traction before the other maneuvers are embarked upon. Bibliography Foulk DM, Mullis BH. Hip Dislocation: Evaluation and Management JAAOS 2010;18: Samuel Sanders, M.D., Nirmal Tejwani, M.D., and Kenneth A. Egol, M.D. Traumatic Hip Dislocation A Review Bulletin of the NYU Hospital for Joint Diseases 2010;68(2):91-96

3 Gregory W. Hendey, MD, Arturo Avila, PA-C. The Captain Morgan Technique for the Reduction of the Dislocated Hip Ann Em Med 2011;6: Travis E. Clegg, Craig S. Roberts *, Joseph W. Greene, Brad A. Prather Hip dislocations Epidemiology, treatment, and outcomes Injury 2010;41: Shim SS Circulatory and Vascular Changes in the Hip Following Traumatic Dislocation Clin Ortho Related Res. 1979;140: Apneic Oxygenation 1959 Frumin demonstrated that a patient could stay oxygenated while not breathing for up to 55 minutes. Weingart and Levine in 2012 advocated nasal cannula at 15 L/min as an adequate delivery method for apneic oxygenation. Many other articles corroborate this idea. The body passively uses oxygen at 250ml/min. It makes carbon dioxide at a rate of 20ml/min. This makes a negative pressure in the alveoli of 230ml/min. This space is filled with gas from the more proximal airway. If the upper airway is filled with 100% oxygen this will be the gas that is transported to the alveoli allowing a passive maintenance of excellent oxygenation in healthy patients. It is interesting that the use of a nasal cannula will work even if the mouth is open. This will allow much longer periods of adequate oxygenation should there be any trouble during the procedure. Many minutes may pass without any intervention other than, perhaps, a jaw thrust or chin lift to clear the airway. I find this is a wonderful technique to use when doing procedural sedation. It buys all the time one needs to do the procedure and takes all the anxiety out it at the same time. Bibliography Frumin MJ, et al. Apneic Oxygenation in Man Anesthesiology 1959;20: Weingart SD, Levitan RM Preoxygenation and Prevention of Desaturation During Emergency Airway Management Ann EM 2012;59: Miguel-Montanes, et al. Use of High-Flow Nasal Cannula Oxygen Therapy to Prevent Desaturation During Tracheal Intubation of Intensive Care Patients With Mild-to-Moderate Hypoxemia. Crit Care Med 2015;43:574-83

4 Dislocated Hip Prosthesis 80% are posterior Incidence 3% of first hip replacements 16% of second hip replacements 25% after multiple replacements Typically levered out where the stem impinges on the edge of the acetabluar cup. Bending deeply at the waist is one of many versions of what activities cause the dislocation. 20% are anterior Mechanism is: Excessive extension, adduction, and external rotation i.e. when taking a long stride the extending leg may lever it out Hip precautions include: Do not cross your legs at least 6-8 weeks Do not flex hip beyond 90 degrees Do not sit on sofas or in low chairs Do not lean forward while you sit down Don't try to pick up something on the floor while you are sitting. Don't turn your feet excessively inward or outward when you bend down. Don't reach down to pull up blankets when lying in bed. Increased risk of dislocation Elderly (decreased muscle mass) Female 2:1 Psychosis, alcoholism Second arthroplasty Signs and Symptoms After a sudden vigorous movement Painful "pop" Pain with motion Pain may be less if after several dislocation Typically assume the same position as a dislocated native hip First dislocation usually occurs within 3 weeks of initial surgery Recurrent dislocations After first dislocation 25%

5 After second dislocation 50% After third dislocation 80% Consequently, corrective surgery usually performed after third dislocation. German in 2005 showed emergency physicians were just as likely to be successful reducing a prosthetic hip dislocation as were orthopedists. A constrained prosthesis is designed to entrap the stems femoral head in the acetabular cup. These are frequently used as a replacement device when there have been previous prosthetic hip dislocations. When constraining devices dislocate it would be very difficult to reduce them and they should be left to the orthopedist to relocate. Look for the metallic ring that is the indicator of the constraining device. Treatment Reduction Check nerve and artery function Post reduction films Place in brace Bibliography Carl A. Germann MD, Daniel A. Geyerb, Andrew D. Perron MD. Closed reduction of prosthetic hip dislocation by emergency physicians Am J Em Med 2005;23: Soong M, et al. Dislocation After Total Hip Arthroplasty J Am Acad Orthop Surg 2004;12:

6 Su EP, Pellicci PM. The role of constrained liners in total hip arthroplasty. Constrained hip Clin Orthop Relat Res. 2004;420: Williams JT, et al. Constrained components for the unstable hip following total hip arthroplasty: a literature review Int Orthop 2007;31: