Understanding Peroneal Nerve Entrapment: Lateral Knee Pain and Weakness

At the Centeno-Schultz Clinic identifying the source of your knee pain and weakness is critical. There are many causes of lateral knee and leg pain. Entrapment of the peroneal nerve as it crosses the fibular head is discussed below.

ANATOMY REVIEW
The sciatic nerve, largest nerve in the body divides into the tibial and common peroneal nerve just above the level of the knee-joint (popliteal fossa).

The common peroneal nerve travels laterally and courses around the fibular neck and passes through an opening in the  peroneus longus muscle. This opening can be quite tough and can result in the nerve angulating through it at an acute angle.

PREVALANCE

Peroneal nerve injuries are the most common peripheral nerve injuries of the lower limb to result from multiple traumatic injuries.  While the nerve can be injured at any site along its path, most peroneal nerve injuries occur at the region of the fibular head.

COMMON CAUSES

Habitual leg crossing

Trauma

Prolonged squatting (strawberry picker’s palsy)

Knee dislocation

Total knee and hip replacement and arthroscopies

PRESENTATION

ALTERED GAIT secondary to weakness or paralyzed muscles that control ankle extension (ankle dorsiflexors).  This can result in foot drop foot where dorsiflexion of the foot is compromised and the foot drags during walking.

PAIN

LOSS OF SENSATION over the lateral knee and leg.

Peroneal Nerve Sensory Distribution

At the Centeno-Schultz Clinic MSK Ultrasound is an essential part of the diagnostic evaluation and allows for direct visualization of platelets and stem cells therapies.

Below is an ultrasound image of the common peroneal nerve at the level of the fibular head.  The nerve is seen on cross-section and identified by the white arrow.  fh=fibular head and lhg is lateral head of gastrocnemius, a major muscle in the calf.

Successful Treatment of Knee Osteoarthritis with Prolotherapy

The Centeno-Schultz Clinic offers a variety of non surgical regenerative therapies to treat spine, knee, hip and ankle pain.  The therapies include prolotherapy,  platelet rich plasma and  bone marrow derived stem cells. (Regenexx SD and Regenexx C).

Prolotherapy is the injection of a hypertonic solution into a joint, tendon or ligament with the purpose of creating chemical micro-injury.  The micro-injury leads to inflammation and subsequent healing.    At the Centeno-Schultz Clinic prolotherapy is performed under the use of x-ray or MSK ultrasound guidance.

Does prolotherapy work?

Traditional medicine has been skeptical due to lack of good quality studies.

Rabago et al recently published the results of a randomized control study comparing saline injections and exercise to prolotherapy for knee osteoarthritis.’

Ninety patients with known knee osteoarthritis  were randomized to undergo injection therapy of either prolotherapy or saline or in -home exercise.  No baseline differences existed between groups.  At 52 weeks there were statistically differences in the pain scores.  Patients receiving  prolotherapy  improved more (P <.05) at 52 weeks than did  scores for patients receiving saline and exercise .  Patient satisfaction was also high with prolotherapy.

CONCLUSIONS Prolotherapy resulted in clinically meaningful sustained improvement of pain, function, and stiffness scores for knee osteoarthritis compared with blinded saline injections and at-home exercises.

Prolotherapy is an effective alternative to common steroid injections in the treatment of knee osteoarthritis.

Successful Treatment of Sciatica: Disc Herniation Location and Clinical Success

At the Centeno-Schultz Clinic knowing which patients will benefit from which procedure is key.

Sciatica due to a lumbar disc herniation can respond favorably to epidural steroid injections. The location of the disc herniation can dictate success.  Previous blogs have discussed the  successful treatment of sciatica with platelet epidural injections (Regenexx PL-M).  Pre and post MRI studies have demonstrated reduction in disc herniation which corresponded with clinical symptoms.

At recent study confirmed what we have known clinically for years.  Lee et al demonstrated that patients with herniated lumbar discs in the foraminal or extra-foraminal zone had excellent clinical response to transforaminal epidural injections.

Basic Definitions

Foramen:  Opening

Neural Foramen:  Boney doorway through which of the spinal nerve root, dorsal root ganglion, the spinal artery pass.

Foraminal zone:  The zone between planes passing through the medial and lateral edges of the pedicles.

The spinal canal can be divided into three zones:  central, foraminal and extra-foraminal.

Spinal Canal Zones

There are two principle types of epidural injections:  transforaminal and interlaminar.  The former is directed towards the neural foramen and exiting nerve root whereas the latter is injected into the posterior epidural space.  Successful treatment is knowing the location of the disc hernation and providing the appropriate epidural injection.  This is the standard of care at the Centeno-Schultz Clinic.