Osteoarthritis of Zygapophysial Joints as a Cause of Back Pain and Neck Pain: A Scoping Review

Osteoarthritis of Zygapophysial Joints as a Cause of Back Pain and Neck Pain:
A Scoping Review

Pain Medicine
May 3, 2024 [epub]

Nikolai Bogduk, MD, PhD; John MacVicar, MB; this study cites 63 references.

“Zygapophysial joints (Z joints) can be a source of back pain and of neck pain, but the cause of pain is not known.”

“Some authors attribute the pain to osteoarthritis but without citing evidence.”

This review was undertaken to assess the evidence of association between spinal pain and osteoarthritis of Z joints, in both cervical and lumbar spines.

The authors reviewed population studies, diagnostic studies, and/or case-control studies.

Z joints = zygapophysial = facet (American) = apophyseal (British) = posterior joints = articular processes

Osteoarthritis = arthritis = degeneration = degenerative changes

[Conflation is the merging of two or more sets of information into one, often in error. This produces errors or misunderstandings].

KEY POINTS FROM THIS ARTICLE:

1) “Although Z joints have been established as a source of spinal pain, the pathology responsible for that pain has been elusive.” [Important]

2) “Z joints are commonly affected by osteoarthritis.”

• “This coincidence has given rise to the contention that osteoarthritis is a common cause of Z joint pain.”
  • “This contention is attractive to physicians because osteoarthritis can be detected on plain radiographs, computerized tomography (CT) scans, or magnetic resonance images (MRI); and finding this pathology provides a convenient explanation for why the joint is painful.”
  • “This contention is also attractive to compensation insurers for, if the patient’s pain can be attributed to naturally occurring osteoarthritis, it can avoid being attributed to a compensable injury.” [Important]
  • “Belief in this contention can adversely affect the practice of pain medicine.”
  • “Despite these adverse effects, this contention continues to be promulgated, both in the pain literature, and in medicolegal proceedings.”
  • “Those who promote the belief do not cite any evidence that supports it.”

3) “Osteoarthritis of the cervical Z joints is so common in the asymptomatic population that its presence on radiographs cannot distinguish an affected joint as one that is currently painful from one that has never been painful.”

• Well-done studies “clearly show no significant association between osteoarthritis of the cervical Z joints and clinically significant neck pain.”
• “Neck pain is independent of the presence of osteoarthritis.”

4) “Osteoarthritis of the lumbar Z joints is so common in asymptomatic individuals that seeing osteoarthritis on plain radiographs, CT scans, or MRI scans is no better than guessing, for distinguishing symptomatic from asymptomatic joints.”

• “Joints responsible for a patient’s back pain are not distinguishable on the basis of the severity of osteoarthritis affecting them.” [Important]
• “Whether or not joints are responsible for a patient’s back pain is independent of the degree to which they are affected by osteoarthritis.”

5) The gold standard for diagnosing osteoarthritic pain is by anesthetizing the joint to see if doing so relieves the patient’s pain.

• These diagnostic blocks must be controlled to reduce the number of false-positive responses and/or placebo.
• “Diagnostic blocks would need to be rigorously controlled, and conducted on a double-blind basis, so that there is no doubt that the index joint(s) is, or is not, the source of pain.”

6) “Some physicians might expect—or even argue—that osteoarthritis of the lumbar Z joints should be painful because osteoarthritis is a known cause of pain in other joints of the body.”

• “There is no doubt that osteoarthritis is associated with pain” in the hips and knees.
• “However, for proximal and distal interphalangeal joints and for metacarpophalangeal joints, … the prevalence of pain does not differ between subjects with and without osteoarthritis, and the prevalence of osteoarthritis does not differ between subjects with and without pain.”

7) Findings:

• “The searches retrieved 11 population studies, 4 diagnostic studies, and 3 case control studies.”
  • “No study showed any positive association between osteoarthritis of Z joints and pain.”
  • “All studies found pain to be independent of the presence or severity of osteoarthritis.”
  • “Osteoarthritis was as common in subjects with no pain as in subjects with pain.”

8) Conclusion:

• “The published evidence does not support the belief that osteoarthritis causes Z joint pain.”
  • “All the evidence contradicts this belief.”

9) “Zygapophysial joints (Z joints), also referred to as ‘facet’ joints, have increasingly been recognized as possible sources of chronic neck pain and chronic low back pain.”

10) “The estimated prevalence of true lumbar Z joint pain (complete relief of pain with diagnostic blocks) is only about 10%.”

• “This means that over 1000 patients would need to be studied in order to harvest 100 with complete relief of pain.”

11) “With respect to the question addressed by the present review, 2 clear conclusions apply.”

• “No study has produced any conclusive evidence that osteoarthritis is a cause of Z joint pain, either in the cervical spine or in the lumbar spine.”
• “Osteoarthritis of Z joints is so common in asymptomatic individuals that, even if it was a cause of pain, it could not be diagnosed with any confidence by any form of currently available medical imaging.”

12) “Osteoarthritis is [a] normal age change unrelated to pain.”

13) “Simply seeing osteoarthritis on images does not distinguish a painful joint from an asymptomatic one.”

14) Studies to date have collectively failed to show that osteoarthritis of Z joints causes pain.

15) “The contention that joints can do so remains no more than a conjecture.”

16) Authors of teaching articles have conflated two concepts, which are false:

• “Facet joint degenerative osteoarthritis is the most frequent form of facet joint pain.”
• Yet, “no one has shown that osteoarthritis causes Z joint pain.”

17) “The concept of Z joint pain should not be contaminated with illegitimate, vain attempts to include pathology in the diagnosis.”

18) “Invoking osteoarthritis [of the Z joints] as the cause of pain is incompatible with the published evidence.” [Key Point]

• “Continuing to perpetuate views that are contrary to the evidence, either intentionally or by inattentive, casual writing, misrepresents that evidence to patients, insurers, and fellow physicians, and in some cases to Courts.”

THE BOTTOM LINE FROM DAN MURPHY:

Facet pain is real. Osteoarthritis of the facet is not a cause of facet pain.

This Review, from the same authors, supports this point:

Article Review 15-22:
The Prevalence of “Pure” Lumbar Zygapophysial Joint Pain in Patients with Chronic Low Back Pain