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Comprehensive Management
Of Chronic Knee Pain
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TORY MCJUNKIN, MD
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Co-founder
Arizona Pain Specialists
Scottsdale, Arizona
PAUL LYNCH, MD
Co-founder
Arizona Pain Specialists
Scottsdale, Arizona
JARRON TILGHMAN, MD
Physical Medicine and Rehabilitation Physician
Rockhill Orthopaedic Specialists
Kansas City, Missouri
PATRICK HOGAN, DO
Anesthesiologist, interventional pain physician
Arizona Pain Specialists
North Phoenix, Arizona
ADAM WUOLLET, MD
Anesthesiologist, interventional pain physician
Arizona Pain Specialists
Phoenix, Arizona
EDWARD SWING, PHD
Research Director
Arizona Pain Specialists
Scottsdale, Arizona
The authors report no relevant financial conflicts of interest.
est
K
nee pain is a very common complaint that
d.
can be debilitating when severe. A proper
evaluation must begin with a thorough
history and physical examination.
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If the patient is not a surgical candidate, there are
several conservative treatment options—such as physical therapy for retraining of proper mechanics, kinesiology taping to improve proprioception, acupuncture
and chiropractic treatment—that may alleviate the
patient’s symptoms (Figure 1). Depending on the
nature of the pain, a variety of analgesic medications
may be prescribed, including anti-inflammatory drugs,
membrane-stabilizing agents and in severe cases, opioid analgesics. Unfortunately, these medications may
not significantly reduce the pain and their long-term
compliance may be limited by untoward side effects.
Additionally, many patients have intractable chronic
pain after more invasive treatment options such as a
total knee arthroplasty (TKA). Studies have reported
that 20% of patients undergoing TKA have persistent postsurgical pain.1 These patients often present
to the pain clinic frustrated by the failure of conservative and possible surgical interventions. Fortunately,
depending on the pain generator, there is a wide array
of interventional treatment options that can be implemented (Figure 2).
Evaluation
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The primary nerve innervation of the knee arises
anteriorly from the femoral nerve and posteriorly
from the sciatic nerve. These nerves give rise to a
number of smaller branches that provide sensation
History and
physical
Diagnostic workup (ultrasound,
x-ray, MRI, NCS/EMG)
Possible surgical candidate?
If yes,
consider early
orthopedic referral
If no,
consider conservative
management
Manual therapy
(PT, chiropractor/DME)
Analgesics
(ibuprofen, NSAIDs)
Behavioral, psych
(biofeedback,
relaxation techniques)
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Figure 1. Conservative treatment algorithm.
DME, durable medical equipment; EMG, electromyography; MRI, magnetic resonance imaging;
NCS, nerve conduction study; NSAID, nonsteroidal anti-inflammatory drug; PT, physical therapy
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to a variety of specific regions around the knee
(Figure 3). The saphenous nerve branches from the
femoral nerve and provides sensation over the distal aspect of the medial two-thirds of the thigh. The
lateral one-third of the distal thigh is supplied by the
superficial femoral cutaneous nerve. The superior
medial, inferior medial, and middle genicular nerves
arise from the tibial nerve—the medial division of the
sciatic nerve. The superior lateral, inferior lateral, and
recurrent tibial genicular nerves arise from the common peroneal nerve—the lateral division of the sciatic nerve.2
A thorough history and physical can aid the clinician in developing a focused differential diagnosis
and effectively managing the patient with knee pain.
Specific location of the pain, cause of the pain, duration of symptoms, alleviating and/or exacerbating factors, associated ipsilateral back and/or hip pain, and
the outcome of any previous interventions should be
investigated. The physical exam should always begin
with inspection of the knee to assess for signs of
gross deformity, edema, or cellulitis. Provocative exam
maneuvers such as the valgus/varus stress, anterior/
posterior drawer, Lachman’s test, McMurray’s test, and
the patellar grind test may provide a great deal of information whether positive or negative. If bony etiology
is suspected, imaging should include an x-ray of the
knee. However, if soft tissue pathology is suspected,
an ultrasound or a magnetic resonance imaging scan
of the knee may be more appropriate. Furthermore,
given that it is common for knee pain to be a manifestation of referred back or hip pain, imaging of these
regions as well as electrodiagnostic studies may be
appropriate. Electrodiagnostic studies also should be
completed if there is any concern for neuropathy. Correlating the patient’s symptoms and physical exam
findings with abnormal diagnostic test results can help
to condense the differential diagnosis and aid in tailoring a treatment plan.3
Ultrasound Versus Fluoroscopically Guided
Injections
Incorrect placement of injectate within the knee can
lead to increased pain and decreased therapeutic benefit. The literature suggests that there is an increased
rate of successful intraarticular placement using image
guidance compared with blind injections (ie, using surface anatomic landmarks). In light of this, ultrasound
and fluoroscopy are both frequently used to perform interventional procedures for knee pain. Each
has advantages and disadvantages with respect to a
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Current Evidence for Interventional Therapy
Phase 1
• Image-guided knee steroid/hyaluronic acid
injection
• Image-guided knee stem cell/PRP injections
Phase 2
• Saphenous and lateral femoral cutaneous nerve block; RFA if successful
• Femoral nerve block, RFA if successful
• Lumbar sympathetic plexus block
(L2, L3); RFA if successful
• Genicular nerve block; RFA if
successful
• Lumbar SCS trial; permanent implant
if successful
• PNS trial; permanent implant if
successful
Phase 3
• Refer back to orthopedic surgeon for
reevaluation
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There is a growing body of literature that supports
the use of a variety of interventional procedures in the
management of knee pain. Raynauld et al demonstrated
improved pain relief with intraarticular steroid injection versus saline over a 2-year period with repeated
injections every 3 months.4 Neustadt et al showed that
intraarticular hyaluronic acid injections brought about
some symptomatic pain relief compared with placebo.5
A study by Choi et al revealed that radiofrequency ablation of the superior medial, superior lateral, and inferior
medial genicular nerves produced significant pain relief
in patients with knee osteoarthritis.6 Wakitani et al demonstrated repair of articular cartilage defects following
intraarticular injection of human autologous mesenchymal stem cells.7
Failed conservative treatment
Figure 2. Nonsurgical knee pain.
PNS, peripheral nerve stimulation; PRP, platelet-rich plasma;
RFA, radiofrequency ablation; SCS, spinal cord stimulation
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Figure 4. Knee ultrasound.
Arrowheads, medial collateral ligament
*Medial meniscus
Distal hip adductor muscles can be seen at the top
of the image.
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Figure 5. Mesenchymal stem cells.
Figure 3. Innervation of the knee.
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Regenerative therapy can include platelet-rich plasma and stem cells. Mesenchymal stem cells may be
procured from autograft bone marrow and adipose
tissue. They also may be harvested from allograft
bone marrow tissue.
intra- and extraarticular injections to confirm accurate location.8,9 For ease of access into the intraarticular joint space, we recommend performing procedures
with the patient in the supine position with the knee
maximally flexed to approximately 135 degrees. It is
important to note that ultrasound is user-dependent,
which makes for more variable results.
Interventional Procedures
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The following is a list of interventional procedures
that are commonly performed in the treatment of
chronic knee pain:
• Intraarticular knee injections: steroids, hyaluronic
acid, traumeel, platelet-rich plasma (PRP), and mesenchymal stem cells (Figure 5).
• Extraarticular knee injections: steroids, traumeel,
PRP, and mesenchymal stem cells.
• Trigger-point injections.
• Peripheral nerve blocks: saphenous, superficial femoral cutaneous, genicular nerves (Figure 6).
• Radiofrequency ablation: saphenous, superficial
femoral cutaneous, genicular nerves.
• Lumbar sympathetic plexus block (typically at L2
and/or L3 level).
• Peripheral nerve stimulation: saphenous, superficial
femoral cutaneous.
• Lumbar spinal cord stimulation: treatment of last
resort.
Figure 6. Peripheral nerve stimulation.
The patient is a 19-year-old female collegiate softball player who failed multiple orthopedic knee surgeries and was unable to participate in athletic
activities. Following placement of peripheral field
stimulation of the knee, she was able to return to
play.
References
Courtesy of Dr. William S. Rosenberg, Center for the Relief of
Pain, Kansas City, Mo.
2. Jacobson JA. Introduction. In: Jacobson JA, ed. Fundamentals of
Musculoskeletal Ultrasound. Philadelphia, PA: Saunders; 2007:1-14.
1.
Beswick AD, Wylde V, Gooberman-Hill R, et al. What proportion of
patients report long-term pain after total hip or knee replacement
for osteoarthritis? A systematic review of prospective studies in
unselected patients. BMJ Open. 2012;2(1).
3. Jacobson JA. Knee ultrasound. In: Jacobson JA, ed. Fundamentals of Musculoskeletal Ultrasound. Philadelphia, PA: Saunders;
2007:224-263.
5. Neustadt D, Caldwell J, Bell M, et al. Clinical effects of intraarticular
injection of high molecular weight hyaluronan (Orthovisc) in osteoarthritis of the knee: a randomized, controlled, multicenter trial. J
Rheum. 2005;32:1928-1936.
6. Choi WJ, Hwang SJ, Song JG, et al. Radiofrequency treatment
relieves chronic knee osteoarthritis pain: a double-blind randomized controlled trial. Pain. 2011;152:481-487.
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given procedure. Fluoroscopy provides better visualization of the knee joint, which improves the likelihood
of successful intraarticular injection. Given the relatively radiopaque appearance of periosteum and hardware from prior TKA, this is ideal for genicular nerve
blocks. However, the patient is subjected to radiation
exposure with its usage. Ultrasound allows for better visualization of soft tissue structures, which can
dramatically improve the success rate of peripheral
nerve and bursa injections in this region (Figure 4).
The normal characteristic appearance of various anatomic structures in the region of the knee aid the interventionalist in target localization. Given the real-time
dynamic nature of this imaging modality, the needle
tip and/or injectate can be easily visualized for both
4. Raynauld JP, Buckland-Wright C, Ward R, et al. Safety and efficacy
of long-term intraarticular steroid injections in osteoarthritis of the
knee. Arthritis Rheum. 2003;48:370-377.
7. Wakitani S, Imoto K, Yamamoto T, et al. Human autologous culture expanded bone marrow mesenchymal cell transplantation for
repair of cartilage defects in osteoarthritic knees.
J Osteo Res Soc Inter. 2002;10:199-206.
8. Waldman SD. Pain Management. Philadelphia, PA: Saunders; 2011.
9. Hurdle M-FB. Ultrasound-guided knee injections. In: Narouze SN,
ed. Atlas of Ultrasound-Guided Procedures in Interventional Pain
Management. New York, NY: Springer; 2011:331-335
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