By: Alesha Metzger, PT, DPT, CFSC-1
Abstract
Background: Functional popliteal artery entrapment syndrome occurs bilaterally in younger, athletic females and can be treated with surgical or conservative interventions. The purpose of this case report is to improve awareness and provide education on post-operative rehabilitation techniques for this rare condition.
Case Description: The patient is an 18-year-old female high school soccer player with a 6-month history of bilateral gastrosoleal claudication and muscle spasms caused by prolonged distance running > 2 miles and resolve with rest.
Outcomes: After one month of conservative treatment, the patient’s LEFS score and symptoms remained the same. She was referred to a vascular surgeon for consult and further imaging which came back positive for bilateral functional popliteal artery entrapment syndrome. Surgery for the left limb was scheduled followed by three months of post-operative physical therapy. Once cleared, surgery was then scheduled for the right limb and patient again underwent three months of post-operative physical therapy. She was able to return to prior level of function with no familiar symptoms after seven months and went on to play Division I soccer.
Discussion: Accurate recognition of symptoms associated with fPAES is required for a clinician to refer to the appropriate specialized physician to then determine if surgical intervention is recommended. A comprehensive rehabilitation guideline for return to sport is important for high level athletes that undergo bilateral fPAES surgery to return to prior level of function.
Key Words: Functional popliteal artery entrapment syndrome, anatomical popliteal artery entrapment syndrome, chronic exertional compartment syndrome, vascular claudication, peripheral artery disease
Background
Popliteal artery entrapment syndrome (PAES) is an uncommon condition which has been described since the late 1800s. The main symptom is exertional leg pain occurring when the popliteal artery is compressed by either abnormal anatomy of the musculotendinous structures in the lower limb or muscle hypertrophy which leads to severe complications including claudication, cramping, numbness, and burning1. Vascular and non-vascular differential diagnoses include arterial endofibrosis, adductor canal compression syndrome, cystic adventitial disease, chronic exertional compartment syndrome, soleal sling syndrome, medial tibial stress syndrome, plantar fasciitis, stress fractures, and low back pain accompanied by referred or radiating leg pain7.
PAES is subdivided into two main types: anatomical and functional1. Anatomical PAES is due to an anatomic variant in the lower limb causing vascular compression, oftentimes found unilaterally in older males with lower activity levels, and typically responds well to surgical intervention3. Functional PAES does not have an anatomic variant, rather, symptoms are believed to be caused by bulky surrounding musculature and repetitive dynamic injury3. The overcrowding of the popliteal fossa due to muscle hypertrophy leads to compression of the neurovascular bundle2. Functional PAES is typically diagnosed bilaterally in a younger female population and the long-term surgical outcomes are worse compared to anatomical PAES1.
Functional PAES (fPAES) can managed conservatively with physical therapy and training modifications, although this is largely ineffective long term as the underlying pathology is not addressed and can lead to eventual cumulative damage to the popliteal artery2. Repeat ultrasound guided botulinum toxin type A (BTX-A) injections have shown promising initial results, but surgical intervention is the most widely accepted treatment for fPAES2, 7.
Case Presentation
History
The patient is an 18-year-old female presenting with a 6-month history of bilateral calf pain that started during her summer club soccer season. She is going into her senior year of high school and committed to play Division I soccer the following year. Symptom onset was insidious in nature and has worsened over the past six months. She reported changing cleats one month ago but did not notice any improvement. Symptoms begin about 2-miles into running or within 25 minutes of play time during a soccer game. She did not report symptoms with jumping or hopping. The patient stated both of her lower legs will begin to feel tight, stiff, crampy, and notices a burning sensation which worsens with prolonged running but resolves with rest. She did report occasional tightness along the bottom of her feet but no numbness. Patient has a history of recurrent bilateral ankle sprains that have been managed with conservative care. She came to this physical therapy clinic direct access and as a result had not had any prior imaging or physician consult.
Clinical Examination
The initial examination consisted of inspection, lumbar spine screening, ankle and foot AROM/PROM, resisted strength testing, stretch testing, stability testing, palpation, and a running gait analysis. Notable findings from the patient examination include bilateral MTP1 extension of 20 degrees, mild pain with palpation along proximal medial calf, and reproduction of familiar symptoms with 5% incline treadmill run at 8mph within 5 minutes of running. All other testing was within functional limits and did not provoke the patient’s symptoms.
Differential Diagnosis
No red flags were present which would indicate a systemic cause and the lumbar spine was ruled out as a source of referred pain into the lower limbs. Popliteal artery entrapment syndrome and chronic exertional compartment syndrome were considered as potential diagnoses but required referral out to a specialist for further testing and imaging to confirm a diagnosis. Functional popliteal artery entrapment syndrome was discussed as a potential primary diagnosis due to her symptom location and pain with palpation along the proximal medial calf, which could be due to a lateralized medial head of the gastrocnemius which is oftentimes debulked surgically in this patient population for symptom resolution3, 5, 7. Additionally, fPAES was considered due to neurogenic vasodysregulation, or Raynaud’s phenomenon, which was occurring in the patient’s feet bilaterally and has been linked to fPAES4.
Treatment
This patient was treated with conservatively with massage, dry needling, orthotics, strengthening, and stretching techniques one-month prior to surgical intervention on her left limb. She then underwent 3-months of physical therapy following the clinic’s post-operative protocol (Tables 1 and 2)6,8. She was cleared for return to sport and by month four she then underwent surgical intervention on her right limb. The patient then repeated the same post-operative protocol with the addition of higher level plyometrics bilaterally since both limbs had been surgically corrected.
Outcome and Follow-Up
At 12-weeks post-operative the patient reported symptom reduction in her left leg. She continued to have familiar symptoms in her right leg throughout the course of treatment until she ultimately had surgery by month four. After repeating her rehabilitation protocol, she was full symptom resolution bilaterally by seven months and was cleared for full return to sport.
Discussion
Functional popliteal artery entrapment syndrome is a rare condition that is oftentimes misdiagnosed by clinicians. It is imperative rehabilitation professionals are able to recognize key characteristics of this condition and refer out for further testing and imaging to confirm diagnosis and begin further treatment of either BTX-A injections or surgical correction. Additionally, there is no standard protocol for post-operative rehabilitation with guidelines for return to sport. This case report proposes a four-phase protocol physical therapists can utilize for these patients.
Several limitations were present in this study and must be taken into consideration. To our knowledge there are no extra tests physical therapists can use to diagnose fPAES in clinic without referring out. Additionally, the long-term outcomes for fPAES are not as favorable as anatomical PAES. This patient was cleared from our clinic and care was transferred to the athletic training staff at the university. It is unknown if this patient continues to have full resolution of symptoms at 12-months post-operative.
Learning Points
- Functional popliteal artery entrapment syndrome is a rare condition that occurs bilaterally and is common in young, female athletes. It requires conservative management, botox (BTX-A) injections, or surgical intervention.
- fPAES is oftentimes misdiagnosed and can lead to long term cumulative damage due to arterial occlusion.
- fPAES has a worse long-term prognosis compared to anatomical popliteal artery entrapment syndrome with surgical intervention.
- There is currently no standardized protocol for post-operative rehabilitation guidelines for return to sport for patients with bilateral fPAES.