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Home > Physical Therapy for the Unhappy Triad or Blown Knee

Physical Therapy for the Unhappy Triad or Blown Knee


Tom Toothaker, PT, DPT

A Blown Knee or the Unhappy Triad is an injury to the knee that damages three knee components simultaneously, the ACL (anterior cruciate ligament), the meniscus and the MCL (medial collateral ligament).  This type of injury is typically seen in sports like skiing, football, and basketball, but can occur during a traumatic accident as well.  When a lateral force is applied to the knee while the foot is in a fixed position on the ground, the knee can torque unnaturally, causing partial or complete tears to the three areas of the knee listed above, all at once. 

This situation is extremely painful, and treatment almost always includes surgery.  During the surgery, the damaged ACL will be repaired or completely replaced with tissue that is either from a cadaver or taken from the Achilles, Quadriceps, Hamstring or Patellar Tendon of the patient.  The injured meniscus may be repaired, or portions removed, preserving as much as possible.  The MCL can heal without surgical intervention.  Recovery from surgery will take anywhere from six months to a year.

Physical Therapy typically begins a few days to two-weeks post-operatively.  The goal is to not overwork the repaired or replaced ligaments while improving the strength and range of motion of the patient, with specific attention to getting them back to the sport or activities and lifestyle they enjoy.  It is important for the patient to understand that PT for the Unhappy Triad is a marathon, not a sprint.  They will be required to put in many hours at the Physical Therapy Clinic, but many more at home, working their exercise program on their own.

Severity of the MCL injury and whether the meniscus is repaired or portions removed will influence rehabilitation time frames.  This includes the length of time the patient will be non-weightbearing, how long a brace will be worn and at what degree the brace will be unlocked to allow for progression of motion.  Non-weightbearing of the surgical leg can be from two to six weeks and the brace may be worn up to twelve weeks post-operatively.  Some form of brace may be worn past the twelve-week mark with return to certain sports.  Icing, elevation and gentle range of motion exercises are recommended in the early stages following surgery. 

The goals in the first phase of rehabilitation are to control swelling, perform exercises for the ankle and hip and begin increasing knee range of motion.  Weight-bearing is increased over time.  For multiple reasons, the quadriceps muscle is typically inhibited following this surgery.  In the clinic, NMES (neuromuscular re-education electrical stimulation) can be used to facilitate muscle recruitment in the early stages, by using an electrical current to recruit muscle fibers to contract involuntarily.  This can be done while the patient actively attempts to contract the quadriceps muscle. 

Goals for the middle stages of rehabilitation are to achieve full weightbearing, continue to increase knee range of motion, increase single leg stability, and strength exercises for the core, hip, knee, and ankle.  Exercises such as weight-shifting, single leg stance, and partial-motion squats are typically performed.

Goals for the late stages of rehabilitation include increasing dynamic single leg stability, compound strength exercises and sport-specific training. 

Remember, just because surgery was performed for this complex injury does not mean all forms of exercise need to be discontinued.  In fact, the opposite should occur.  If you are mindful of the position and stress placed on the surgical leg, a wide range of upper body and core exercises can be performed.  Continuing with a whole-body exercise routine can improve your mental state and positively impact the healing and rehabilitation process! 

Make an appointment with Dr. Toothaker or another OSC provider by clicking the “Request Appointment” button below or by calling (757) 596-1900.  

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