Knee Problems
                                =============
þ Dislocations
 - Beware of spontaneously reduced knee dislocation, when faced with
   severe, bicruciate ligamentous injury with an unstable knee.
 - Do quick exam for gross looseness - if so, check for vascular injury
 - In half to two-thirds of cases of knee dislocation, spontaneous reduction
   has occurred prior to evaluation.
 - When reducing, be gentle - usually quite easy
 - Vascular injury in 10-30%
 - Always do vascular exam:
  + traditional: knee dislocation > angiogram
  + more selective approach:
   - check for expanding hematoma, pulse deficit
   - Arterial Pressure Index: compare ankles bilaterally, if < 10% difference, 
     OK, serial exams and observation instead of angiogram [Hollis, J Trauma 
     2005, Klineberg, J Trauma 2004]

þ Patellofemoral Syndrome
 - Young females
 - insidious onset
 - test available

þ Decision Rules for X-raying Knees:
 - Pittsburgh Rules say get x-ray acute knee pain if
  + fall or blunt trauma mechanism, or
  + age <12 or >50 or
  + inability to ambulate in the ED
 - Pgh rules were 90% sensitive (and better than the Ottowa rule) in one
   study:
   [Seaberg DC, Yealy DM, Lukens T, Auble TE, Mathias SR. Multicenter
   comparison of two clinical decision rules for knee radiographs. Acad Em Med
   1996;3(5):392 [abstract]]

þ Segond Fracture (?sp)
 - Small chip of lateral tibial plateau
 - 98% association with ACL tear
 - per Dr. Phil Saba, Mercy Radiology

þ Knee Dislocations:
(email from Bob MacNamara, Nov 02):
        Michael,
        the consensus seems to be angiography.
        To the list,
                Angiography is the tradition which will likely be hard to
break given the notoriety of this injury but there is literature
supporting a selective approach.  This literature essentially states if
there is a pulse deficit or ischemia at any time (i.e.  before or after
reduction) get the arteriogram otherwise observe.  See:
         Kendall RW. J Trauma 1993;35: 875.
        Dennis JW. J Trauma 1993;35:692.

                Two points that I find of great interest with knee
dislocations are:
1)      They can occasionally occur with minor trauma such as stepping in
a hole or slipping on the floor!
                                See: Shields L. J Trauma 1969;9:192 and
Kennedy JC. JBJS (American) 1963;45:889. 2)      A severely unstable but
not dislocated knee defined as one having greater than 30 degrees of
recurvatum (hyperextension when lifted by the foot) or other signs of
major ligamentous injury is at nearly equal risk for vascular injury as a
dislocated knee.
                See: Varnell RM. Am Surgeon 1989;55:699.