#33 – Hip Disorders #1



Avascular Necrosis of The Hip


  • 200,000-300,000 estimated new cases each year in the United States
  • Cause of approximately 10% of total hip replacements
  • Mean age at time of diagnosis is < 50 years


Pathogenesis and Etiologies

Current thoughts on exact mechanisms are an area of hot debate, but include:

  • Genetic predisposition
  • Metabolic factors
  • Vascular factors
    • Vascular damage
    • Increased intraosseous pressure
    • Mechanical stresses

80% of all atraumatic cases of AVN are due to:

  • Glucocorticoid Use
    • Theories
      • Microemboli in the arteries of the bone from alterations in lipid metabolism
      • Increased bone marrow adipocyte size and number causing decreased venous outlow
      • Changes venous endothelial cells of the bone leading to stasis and necrosis
    • Dose of prednisone < 15-20 mg/day has lowest risk of developing AVN (<3%)
  • Alcohol Use
    • Causes fat emboli, venous stasis, elevated cortisol, and adipocyte hyperrophy
    • While not considered an absolute risk factor, it is associated with up to 31% of AVN cases


Trauma can also predispose patients to develop AVN and most commonly associated with:

  • Femoral neck fracture
  • Hip dislocations


Other atraumatic causes of AVN include sickle cell disease, Gaucher disease, decompression disease, treatment for ALL, and transplantation


Signs and Symptoms

  • Pain
    • Groin, thigh, and/or buttock pain
    • Worse with weightbearing or motion
      • Although 2/3rd may have rest pain
      • 1/3rd may have night pain
    • Decreased ROM with forced internal rotation and abduction
    • Limp



  • Plain Radiographs
    • May not see any changes early in disease course
    • Progression of changes
      • Decreased density –> sclerosis –> subchondral radiolucency (crescent sign) and collapse
  • Magnetic Resonance Imaging
    • Much more sensitive than plain films
      • May see early changes undetectable on plain radiographs
        • T1 – Signal low-density line differentiating healthy and ischemic bone
        • T2 – Second high-density line showing hypervascular granulation


Classification and Staging

In 1993, The Association of Research Circulation Osseous (ARCO) staging system for AVN was developed to unify descriptions for treatment and research purposes.



The goal of treatment is to preserve the native joint for as long as possible.

  • Nonoperative Management
    • Generally ineffective at halting the process
    • Includes bed rest, partial weightbearing, and pharmacotherapeutics
      • Bisphosphonates
        • Slows bone resorption
      • Vasodilators
        • Decrease intraosseous pressure and improve blow flow
      • Statins
      • Anticoagulants
  • Joint-Preserving Procedures
  • Total Joint Replacement


Slipped Capital Femoral Epiphysis (SCFE)


  • Displacement of the capital femoral epiphysis from the neck of the femur through the physeal plate anterolaterally and superiorly


Risk Factors

  • Obesity is #1 risk factor
    • > 60% of patients in > 90th percentile for weight
  • Renal failure
  • History of radiation therapy
  • Endocrine abnormalities
    • Hypothyroidism, GH deficiency


Signs and Symptoms

The most common clinical presentation of SCFE are pain and altered gait, but can be divided into four presentation patterns:

  • Preslip
    • (+) pain, but no radiographical displacement of epiphysis
    • May show widening of the physis
  • Acute
    • < 3 weeks duration
    • (+) joint effusion but no metaphyseal remodeling
    • 10-15% of initially presentation of hip pain and often associated with trauma
  • Acute-on-chronic
    • Worsening symptoms in known SCFE
  • Chronic
    • Most common pattern of presentation
    • Vague, intermittent symptoms > 3 weeks
    • (+) metaphyseal remodeling but no effusion

Pain is classically characterized as dull, aching in the hip, groin, thigh, or knee.  Physical exam reveals decreased internal rotation and abduction ROM with increased pain.  Passively flexing the affected hip while the leg is extended will cause external rotation and abduction.



  • Stable Slips
    • Walking and weightbearing still possible with or without crutches
  • Unstable Slips
    • No ability to weightbear, even with crutches
    • No examination of the ROM of the hip should occur until orthopaedic consultation


Radiographic Evaluation

Most SCFE are diagnosed by plain radiography and have characteristic findings on each view:

  • AP view
    • Mild, widening, lucency, and irregularity of the physis
    • Blurring of the junction between metaphysis and growth plate
    • Klein’s Line
      • Normal = intersecting lateral portion of femoral head from superior femoral neck
      • SCFE = line passes outside of epiphysis
  • Lateral View
    • Usually obtained via frog-leg or cross-table
      • Unstable SCFE should have true lateral
    • Posterior displacements are best seen on lateral views


Grading of Severity

2 ways to grade severity: Displacement of femoral neck or Angle of Southwick.

  • Displacement
    • Mild = < 1/3rd the diameter of the femoral neck
    • Moderate = > 1/3rd, but < 2/3rd the diameter of the femoral neck
    • Severe = > 2/3rd the diameter of the femoral neck
  • Angle of Southwick
    • Mild = < 30o
    • Moderate = 30-60o
    • Severe = > 60o



All SCFEs must be repaired surgically and the goals of surgery are to stabilize the diseased physis to prevent further slippage and avoid complications (AVN).  Treatment of choice is a single cannulated screw placed in the center of the epiphysis.


  1. Moya-Angeler J, Gianakos AL, Villa JC, Ni A, Lane JM. Current concepts on osteonecrosis of the femoral head. World Journal of Orthopedics. 2015; 6(8):590-601. [pubmed]
  2. Mankin HJ. Nontraumatic necrosis of bone (osteonecrosis). The New England journal of medicine. 1992; 326(22):1473-9. [pubmed]
  3. Jones JP. Fat embolism and osteonecrosis. The Orthopedic clinics of North America. 1985; 16(4):595-633. [pubmed]
  4. Dilisio MF. Osteonecrosis following short-term, low-dose oral corticosteroids: a population-based study of 24 million patients. Orthopedics. 2014; 37(7):e631-6. [pubmed]
  5. Fukushima W, Fujioka M, Kubo T, Tamakoshi A, Nagai M, Hirota Y. Nationwide epidemiologic survey of idiopathic osteonecrosis of the femoral head. Clinical orthopaedics and related research. 2010; 468(10):2715-24. [pubmed]
  6. Shigemura T, Nakamura J, Kishida S. The incidence of alcohol-associated osteonecrosis of the knee is lower than the incidence of steroid-associated osteonecrosis of the knee: an MRI study. Rheumatology (Oxford, England). 2012; 51(4):701-6. [pubmed]
  7. Slobogean GP, Sprague SA, Scott T, Bhandari M. Complications following young femoral neck fractures. Injury. 2015; 46(3):484-91. [pubmed]
  8. LaPorte DM, Mont MA, Mohan V, Jones LC, Hungerford DS. Multifocal osteonecrosis. The Journal of rheumatology. 1998; 25(10):1968-74. [pubmed]
  9. Mont MA, Hungerford DS. Non-traumatic avascular necrosis of the femoral head. The Journal of bone and joint surgery. American volume. 1995; 77(3):459-74. [pubmed]
  10. ARCO Staging System. http://arco-intl.org/Newsletters/Gardeniers-1993-5-2/Gardeniers-1993.htm
  11. Loder RT. The demographics of slipped capital femoral epiphysis. An international multicenter study. Clinical orthopaedics and related research. 1996; [pubmed]
  12. Benson EC, Miller M, Bosch P, Szalay EA. A new look at the incidence of slipped capital femoral epiphysis in new Mexico. Journal of pediatric orthopedics. 2008; 28(5):529-33. [pubmed]
  13. Murray AW, Wilson NI. Changing incidence of slipped capital femoral epiphysis: a relationship with obesity? The Journal of bone and joint surgery. British volume. 2008; 90(1):92-4. [pubmed]
  14. Koop S, Quanbeck D. Three common causes of childhood hip pain. Pediatric clinics of North America. 1996; 43(5):1053-66. [pubmed]
  15. Causey AL, Smith ER, Donaldson JJ, Kendig RJ, Fisher LC. Missed slipped capital femoral epiphysis: illustrative cases and a review. The Journal of emergency medicine. 1995; 13(2):175-89. [pubmed]
  16. Reynolds RA. Diagnosis and treatment of slipped capital femoral epiphysis. Current opinion in pediatrics. 1999; 11(1):80-3. [pubmed]


Achilles Tendon


Other Known AliasesCalcaneal tendon

DefinitionThe tendon attaching the gastrocnemius, plantaris, and soleus muscle to the calcaneus.


Clinical Significance The Achilles tendon is the thickest tendon in the body and rupturing this structure takes a tremendous amount of force.  Powerful plantarflexion while jumping is the most common mechanism and most commonly occurs in inflammed or chronically stressed tendons.

History – I am a bit of a mythology geek and I love this eponym.  The Achilles tendon was named after the famous Greek warrior, Achilles, who was the hero of the Trojan War for killing Prince Hector, son of King Priam of Troy.  This is a major part of Homer’s Illiad. 

I digress…..

The reason for this eponym is that Achilles’ mother is Thetis, an immortal sea nymph, who could not bear to see her child injured or killed.  To remedy this, she dipped him in the River Styx to make him invulnerable.  Since he was mortal, she couldn’t just drop him in, so she held him by the heel.  The spot on his heel that was held by Thetis was unprotected and ultimately would be his “Achilles Heel” (get it) when an arrow shot by Paris, brother of Hector, pierced this spot and killed him.

Image result for achilles river styxThetis dipping Achilles in the River Styx by Thomas Banks 02.jpg

Image result for achilles arrow to the ankle



  1. Firkin BG and Whitwirth JA.  Dictionary of Medical Eponyms. 2nd ed.  New York, NY; Parthenon Publishing Group. 1996.
  2. Bartolucci S, Forbis P.  Stedman’s Medical Eponyms.  2nd ed.  Baltimore, MD; LWW.  2005.
  3. Yee AJ, Pfiffner P. (2012).  Medical Eponyms (Version 1.4.2) [Mobile Application Software].  Retrieved http://itunes.apple.com.
  4. Whonamedit – dictionary of medical eponyms. http://www.whonamedit.com

PAINE #PANCE Pearl – Musculoskeletal


What is a good mnemonic for the red flag history and/or symptoms of acute back pain?




The majority of the back pain you will see in clinical practice is non-emergent, but you need to be able to identify the cases that need emergent referral, consultation, or imaging.  Just remember TUNAFISH……


  1. Trauma
    1. Any trauma can cause fracture and cord compromise.  Back pain + trauma = imaging
  2. Unintentional weight loss
    1. Think vertebral metastasis of cancer
  3. Neurologic deficits
    1. Big ones are saddle anesthesia and bowel/bladder dysfunction.  Paresthesias, weakness, and numbness are concerning, but emergent.
  4. Age > 50
    1. New-onset back pain in patients > 50 years old can be cancer, infection, or AAA
  5. Fever
    1. Again…think osteomyelitis, spinal abscess, or cancer
  6. IVDU
    1. Hematogenous infectious seeding of the vertebral bodies or spinal abscess
  7. Steroid Use
    1. Chronic steroid use weakens bones and even low energy mechanisms or spontaneous fractures are possible
  8. History of cancer
    1. Metastases



  1. Della-Giustina D. Evaluation and treatment of acute back pain in the emergency department. Emergency medicine clinics of North America. 2015; 33(2):311-26. [pubmed]
  2. Borczuk P. An evidence-based approach to the evaluation and treatment of low back pain in the emergency department. Emergency medicine practice. 2013; 15(7):1-23; Quiz 23-4. [pubmed]
  3. FoamCast.  Episode 66 – Back pain and spinal epidural abscess.  http://foamcast.org/2017/03/12/episode-66-back-pain-and-spinal-epidural-abscess/
  4. REBEL Review #56.  Red Flags of Back Pain.  https://twitter.com/srrezaie/status/410623799000719361
  5. EM Cases.  Low Back Pain Emergencies. https://emergencymedicinecases.com/episode-26-low-back-pain-emergencies/


Lisfranc Injury


Other Known AliasesTarsometatarsal fracture/dislocation

DefinitionFracture/dislocation of the articulation of the tarsal bones with the metatarsals of the foot.

Clinical Significance The Lisfranc joint of the foot is where the first three metatarsals articulate with the three cuneiforms and the fourth and fifth metatarsals articulate with the cuboid. The Lisfranc ligament attaches the medial cuneiform to the 2nd metatarsal bone on the the plantar surface of the foot.  This is a very serious injury of the foot and sometimes may simple present as a bad sprain.  This injury is most common seen with direct crush injuries and indirect load onto a plantar flexed foot.

Image result for lisfranc jointRelated imageImage result for lisfranc ligament

History – This injury was first described by Jacques Lisfranc de St. Martin (1790-1847), a French surgeon who served in Napoleon’s army in 1813.  He noted this injury pattern in Calvary soldiers who fell from their horse and caught their foot in the stirrup. 


Image result for jacques lisfranc


  1. Firkin BG and Whitwirth JA.  Dictionary of Medical Eponyms. 2nd ed.  New York, NY; Parthenon Publishing Group. 1996.
  2. Bartolucci S, Forbis P.  Stedman’s Medical Eponyms.  2nd ed.  Baltimore, MD; LWW.  2005.
  3. Yee AJ, Pfiffner P. (2012).  Medical Eponyms (Version 1.4.2) [Mobile Application Software].  Retrieved http://itunes.apple.com.
  4. Whonamedit – dictionary of medical eponyms. http://www.whonamedit.com
  5. Welck MJ, Zinchenko R, Rudge B. Lisfranc injuries. Injury. 2015; 46(4):536-41. [pubmed]
  6. Chaney DM. The Lisfranc joint. Clinics in Podiatric Medicine and Surgery. 2010; 27(4):547-60. [pubmed]


Aviator’s Astragalus


Other Known AliasesNone

Definition – Any fracture dislocation of the talus.

Clinical Significance None.  This is an antiquated term for talar injuries

History – First coined in 1919 by Henry Graeme Anderson, who was a consulting surgeon for the Royal Flying Corps during World War I.  He described 18 cases of fracture and dislocation of the talus in pilots between 1914-1919.  During the early history of flight, planes did not reach lethal speeds and when they crashed, the rudder bar (which was controlled by the pilot’s feet) would get driven up into the instep of the foot just anterior to the calcaneous.

Image result for plane rudder bar world war one

Image result for talus fracture mechanism


  1. Firkin BG and Whitwirth JA.  Dictionary of Medical Eponyms. 2nd ed.  New York, NY; Parthenon Publishing Group. 1996.
  2. Bartolucci S, Forbis P.  Stedman’s Medical Eponyms.  2nd ed.  Baltimore, MD; LWW.  2005.
  3. Yee AJ, Pfiffner P. (2012).  Medical Eponyms (Version 1.4.2) [Mobile Application Software].  Retrieved http://itunes.apple.com.
  4. Whonamedit – dictionary of medical eponyms. http://www.whonamedit.com
  5. Anderson HG.  The Medical and Surgical Aspects of Aviation.  The Henry Frowde Oxford University Press.  London, 1919
  6. Coltart WD.  Aviator’s Astragalus.  Journal of Bone and Joint Surgery. 1952;34(4):545-566.
  7. Lee P.  Musculoskeletal Colloquialisms: How Did We Come Up with These Names?.  Radiographics.  2004;24(4):1009-1027.

Answer to Orthopaedic Question

Question #1 – What are the muscles that make up the rotator cuff?


Answer – Supraspinatus, Infraspinatus, Teres Minor, and Subscapularis



Question #2 – What is AT LEAST one maneuver to assess each of these muscles

Keep in mind, there are several maneuvers of the shoulder and many overlap into other structures.  These are the more common individual maneuvers that I think general practice PAs need to know.


Drop Arm test

Description – Patient is seated with examiner to the front. Examiner grasps the patient’s wrist and passively abducts the patient’s shoulder to 90 degrees. Examiner releases the patient’s arm with instructions to slowly lower the arm. Test is positive if the patient is unable to lower his or her arm in a smooth, controlled fashion


Dropping Sign

Description – The patient stands with the arm at the side with the elbow at 90 degrees and the humerus medially rotated to 45 degrees. Patient then resists external rotation. Pain or the inability to resist medial rotation indicates a positive test for an infraspinatus strain.

Teres Minor

Hornblower (Patte) Test

Description – Elevate the patient’s arm to 90 degrees in the scapular plane and then flex the elbow to 90 degrees, and the patient is asked to laterally rotate the shoulder. A positive test occurs with weakness and/or pain.


Lift Off (Gerber) Test

Description – The patient stands and places the dorsum of the hand against mid-lumbar spine. The patient then lifts hand away from the back. An inability to perform this action indicates subscapularis weakness or injury.


  1. Physical Therapy Haven – Shoulder
  2. iOrtho App