A 67-year-old male with a history of bilateral total hip arthroplasties (THA) several years ago presents with left hip pain after a fall. He was walking downstairs and slipped, twisting his leg internally and with adduction and flexion of the hip to catch himself. He denies falling but felt an immediate pop in his left hip and could no longer bear weight. AP and lateral radiographs of the pelvis and left hip were obtained and are shown above (Image 1. Case courtesy of Dr Andrew Taylor, Radiopaedia.org, rID: 67457).

 

Posterosuperior prosthetic hip dislocation. 
  • Pearl: In native joints, posterosuperior hip dislocations are the most common (~90%) with anterior dislocations being much less common [1]. These trends are similar in total hip arthroplasties (THA) especially due to the common posterior approach breaching the posterior soft-tissue stabilizers.
  • Pearl: Periprosthetic hip fractures can also occur with or without dislocations and can be easily missed if there is an obvious dislocation distracting you!
prosthetic hip dislocation

Figure 2: AP and lateral radiographs of the pelvis and left hip, notice the superior and posterior displacement of the artificial femoral head in relation to the glenoid (green annotation): Case courtesy of Dr. Andrew Taylor, Radiopaedia.org, rID: 67457.

In native hips, common complications of hip dislocations include avascular necrosis of the femoral head, post-traumatic arthritis, and sciatic nerve injury. In a prosthetic hip, the major complication is a sciatic nerve injury, which occurs in approximately 10% of cases [1].
  • Pearl: In native hips, the time from dislocation to reduction is critical as the risk for avascular necrosis of the femoral head increases significantly after 6 hours of dislocation [2].
  • Pearl: The sciatic nerve has many functions but can be tested quickly by assessing the sensation of the lateral lower leg and the sole of the foot and/or by checking the extensor hallucis longus muscle (EHL) by asking the patient to extend their great toe against resistance.

Management in the ED includes expedited reduction with neurovascular status checked before and after. There are numerous techniques for the reduction but all will require some form of moderate sedation to facilitate maximal relaxation of the large, strong muscles of the pelvis to optimize the chance of successful reduction. All reduction techniques for a posterior dislocation focus on flexion at the hip and in-line traction. There are several described techniques; a great review article describing them is listed below. Generally speaking, 1-2 attempts with each method are enough to determine whether it will work, and subsequent attempts using the same method are discouraged.

  • Pearl: A review article on many of the described hip reduction techniques (including photos) [3].

For an uncomplicated native hip dislocation that is successfully reduced, orthopedics does not need to be consulted in the ED. For a prosthetic hip dislocation with successful reduction, they also don’t NEED to be consulted, but this is highly dependent on institutional policies. If the hip was operated on by a surgeon at your facility, they typically want to be involved in the case. All cases should be referred to orthopedics for outpatient follow-up.

Resources & References:

Check out ALiEM’s Paucis Verbis cards to brush up on other can’t-miss orthopedic injuries, and SplintER Series or EMrad for more cases.

  1. Masiewicz S, Mabrouk A, Johnson DE. Posterior Hip Dislocation. [Updated 2022 Feb 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459319/
  2. Dawson-Amoah K, Raszewski J, Duplantier N, Waddell BS. Dislocation of the Hip: A Review of Types, Causes, and Treatment. Ochsner J. 2018;18(3):242-252. PMID: 30275789.
  3. Waddell BS, Mohamed S, Glomset JT, Meyer MS. A Detailed Review of Hip Reduction Maneuvers: A Focus on Physician Safety and Introduction of the Waddell Technique. Orthop Rev (Pavia). 2016;8(1):6253. Published 2016 Mar 21. PMID: 27114811.
R. Conner Dixon, MD

R. Conner Dixon, MD

Clinical Instructor
Sports Medicine Fellow
Department of Emergency Medicine
Georgetown University/Medstar Washington Hospital Center
R. Conner Dixon, MD

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Katherine WD Dolbec, MD, FACEP, CAQSM

Katherine WD Dolbec, MD, FACEP, CAQSM

Assistant Professor
Department of Surgery, Division of Emergency Medicine
University of Vermont Larner College of Medicine
Katherine WD Dolbec, MD, FACEP, CAQSM

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Alexander J. Tomesch, MD

Alexander J. Tomesch, MD

Primary Care Sports Medicine Fellow
Department of Orthopedic and Sports Medicine
University of Arizona - Tucson
Alexander J. Tomesch, MD

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