Our patient is a 33 year-old female runner complaining of hamstring and calf tightness, and posterior knee pain in both legs. The pain began in 2015, but she continued to run.
The Challenge
The patient had seen numerous running physical therapists and had undergone multiple gait analyses without any results. Five years prior she had sustained tears in the medial collateral ligament (MCL) and posterior cruciate ligament (PCL) in the right knee when windsurfing.
Our Diagnostic Approach
3D Gait Analysis
We conducted a 3D gait analysis using advanced technologies and proprietary software to get an objective picture of the patient’s gait mechanics. Gait analysis results revealed multiple issues:
Excessive pronation bilaterally, worse on the left
Left foot crossover.
Oversupination on push-off
Low rear push-off bilaterally
Bilateral varus (bow-legged) thrust, worse on the right
Limited hip extension bilaterally
Excessive pelvic rotation
Excessive vertical oscillation
Weakened pretibial muscles bilaterally
Bilateral pelvic drop, worse on the right
External tibial rotation on the left
Entire left leg has excessive internal rotation, most likely a compensation pattern from unloading of the right leg
Low cadence (steps per minute), increasing ground reaction forces
Greater right foot ground contact
Clinical Exam
We conducted a battery of tests and assessments to evaluate posture and biomechanics. We determined that the patient:
Had an excessive Q angle while standing – the angle between a line extending from the top of the anterior iliac bone and the midpoint of the patella, and a line from the midpoint of the patella to the tibial tuberosity.
Had noticeable bilateral tibial varum (bowing).
Failed to load her medial arches and big toes, especially on the left.
Had an inverted left foot.
Had bilateral raised 1st metatarsals.
Had bilateral varus thrust during running.
Compensated for right knee pain by slight flexion during heel strike.
Had a positive slump test on the right side.
We elicited Tinel’s sign (pins-and-needles) by palpating the tibial nerve where it passes through the popliteal fossa – a diamond-shaped space behind the knee joint.
Manual palpation of the popliteal fossa and the calf revealed loss of popliteal and crural fascia gliding.
Ultrasound Imaging of the Right Knee
We used high-resolution diagnostic ultrasound to visualize the patient’s right knee:
We found a mild suprapatellar effusion, with slight wear of the trochlear cartilage. indicating mild chondromalacia – erosion of the hyaline cartilage.
There was excessive movement of the posterior cruciate ligament (PCL) during dynamic knee extension.
The right popliteus muscle had hypertrophied and its fascia had thickened.
The posterior oblique and popliteal oblique ligaments and the joint capsule were hyperechoic and appeared to be thickened.
There was reduced neural dynamic motion between the tibial and peroneal branches of the sciatic nerve during dynamic plantarflexion.
The tibial nerve appeared larger than normal, with a thickened perineurium, and responded positively to sono palpation compared to the left side.
Our Diagnosis
Mechanical
Bilateral dynamic thrust was worse on the right leg
There was posterior-lateral instability of the right knee
Neurogenic
We identified dynamic neurogenic entrapment of the tibial nerve
We noted abnormal sciatic nerve mechanics
Soft tissues
Fascial distortion was affecting the entire lower posterior chain
Discussion
When conducted by an experienced clinician who can clinically interpret results, 3D gait analysis can be an extremely useful tool. However, even the most advanced gait analysis system cannot always explain the reasons for mechanical deficits. The data produced tells us what is wrong, but we still have to figure out the underlying cause, and differentiate compensation patterns from pathology. Diagnosis requires clinical experience, and expertise with other diagnostic tools such as high resolution diagnostic ultrasonography.
In this instance, an athlete was originally diagnosed with minor quadriceps muscle strain and was treated for four weeks, with unsatisfactory results. When he came to our clinic, the muscle was not healing, and the patients’ muscle tissue had already begun to atrophy.
Upon examination using MSUS, we discovered that he had a full muscle thickness tear that had been overlooked by his previous provider. To mitigate damage and promote healing, surgery should have been performed immediately after the injury occurred. Because of misdiagnosis and inappropriate treatment, the patient now has permanent damage that cannot be corrected.
The most important advantage of Ultrasound over MRI imaging is its ability to zero in on the symptomatic region and obtain imaging, with active participation and feedback from the patient. Using dynamic MSUS, we can see what happens when patients contract their muscles, something that cannot be done with MRI. From a diagnostic perspective, this interaction is invaluable.
Dynamic ultrasonography examination demonstrating the full thickness tear and already occurring muscle atrophy due to misdiagnosis and not referring the patient to proper diagnostic workup
Demonstration of how very small muscle defect is made and revealed to be a complete tear with muscle contraction under diagnostic sonography (not possible with MRI)
Complete tear of rectus femoris with large hematoma (blood)
Separation of muscle ends due to tear elicited on dynamic sonography examination
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