UW Patella Dislocation Guidelines
UW Patella Dislocation Guidelines
UW Patella Dislocation Guidelines
Reconstruction
Figure 1. Radiograph of the patellofemoral joint with the knee in slight flexion. The lateral aspect of the trochlear
groove is normally about 1 cm higher than the medial.
The knee consists of four bones that form three Proper stabilization of the patella is also affected
joints. The femur is the large bone in the thigh and by the soft tissue structures (ligaments and
attaches by ligaments and a capsule to the tibia, muscles) surrounding the knee. The medial
the large bone in the lower leg commonly referred patellofemoral ligament (MPFL) is a continuation of
to as the shin bone. Next to the tibia is the fibula, the deep retinaculum and vastus medialis oblique
which runs parallel to the tibia on the outside of the (VMO) muscle fibers (inner portion of the
leg. The patella, commonly called the kneecap, is quadriceps muscle) on the inside of the knee.
embedded in the quadriceps and patellar tendon These structures provide a significant force (near
which articulates with the front of the femur, which 60% total) against lateral displacement of the
forms the patellofemoral joint. The patella acts as a patella, as their force is directed inward or
pulley to increase the amount of force that the medially.2,4 The MPFL is the primary restraint to
quadriceps muscle can generate.1 The patella sits in lateral displacement of the patella during the first
a groove on the end of the femur called the 20 to 30 degrees of knee flexion.3 This ligament is
trochlear groove. This groove varies in depth from a passive stabilizer and extends from the upper
person to person. When the knee bends, the inner side of the patella to the medial aspect of
patella travels down the groove and as the knee the femur. The patellomeniscal ligament and
straightens the patella moves up the groove. As retinaculum also contribute more than 20% of the
the patella travels up and down in the trochlear restraining force.
groove, the patella should maintain congruent
boney alignment, which is often referred to as
normal patellar tracking.
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Phase I (surgery to 6 weeks after surgery)
Suggested therapeutic exercise • Gait drills with emphasis on symmetrical loading, heel strike at
initial contact, appropriate quad activation during stance (avoid
hyperflexed or hyperextended knee during mid-stance), and
adequate push-off
• Range of motion (ROM): (pearl: provide manual lateral patellar
stabilization when first initiating range of motion)
• Knee extension with foot propped on bolster
• Heel slides
• Knee flexion wall slides
• Passive knee flexion over edge of plinth
• Medial Patellar mobilizations
• Prone knee flexion
• Strengthening:
Note: it is recommended that all quadriceps strengthening be
performed in conjunction with neuromuscular electrical stimulation
(NMES). Please see Appendix for recommendations on NMES units
for patients, parameters for use, and treatment recommendations
for NMES during quadriceps strengthening.
• Quadriceps, hamstring, and gluteal sets
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• Four-way leg lifts in standing or lying down positions for
hip strengthening
• Bridging
• Ankle isotonics with resistance band
• Weight shifting drills
• Heel raises
• Balance drills beginning with double leg and progressing to
single leg
• Trunk stability work
• Supine core and transverse abdominus activation with
upper and/or lower extremity movement
• Anti-rotation press variations in stable lower extremity
positions
• Suitcase carry with gait and/or marching drills
Cardiovascular exercise • Upper body circuit training or use of an upper body ergometer
Progression criteria • Non-painful knee flexion AROM to 90 degrees
• Full weight bearing with normalized gait mechanics without the
use of assistive device
• Single leg balance for 15 seconds with good control
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Phase II (begin after meeting Phase I criteria, usually 6 weeks after surgery)
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Progression criteria • Normal gait on level surfaces
• LSI >90% on single leg press and Y-Balance
• Quadriceps strength deficit of <30% on Biodex strength test
• At least 12 weeks after surgery
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Phase III begin after meeting Phase II criteria, usually 12-16 weeks after surgery)
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Phase IV (begin after meeting Phase III criteria, usually 20 weeks after surgery)
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Appendix
o Quadriceps NMES to begin as early as possible after surgery with a high-volume approach (1 or more
times per day).
o After 1 week of treatment, assess patient’s response to NMES to gauge effectiveness – Fitzgerald criteria
is recommended as a clinically feasible way to assess the patient’s response
o If patient is responding well, continue treatment for 2 more weeks
o Re-assess response to NMES – look for signs of activation failure:
Inability to perform straight leg raise without extensor lag
In ability to consistently perform quadriceps set with superior patellar glide
Patient reported difficulty with muscle control
o If activation failure is present, continue treatment with high-volume
o If activation failure is NOT present, progress to quadriceps NMES with a low-volume approach
(approximately 3-6 times per week)
Figure 3. Recommended treatment algorithm from Spector et al. for application of NMES with quadriceps
strengthening following knee surgery.
*Fitzgerald criteria: NMES should produce full tetanic contraction of quadriceps with a visual and/or
palpable superior patellar glide
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References
At UW Health, patients may have may receive direction or educational materials that vary from this
information. This information is not intended to replace the care or advice given by your physician or
health care provider. It is neither intended nor implied to be a substitute for professional advice. Call your
health provider immediately if you think you may have a medical emergency. Always seek the advice of
your physician or other qualified health provider prior to starting any new treatment or with any question
you may have regarding a medical condition.
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