Atlantoaxial Osteoarthritis
Atlantoaxial osteoarthritis is a clinical condition characterized by pain at the junction between the back of the head and the neck (occipitocervical pain), retroauricular pain (behind the ear), and reduced rotational movement of the neck. It differs from nerve-root-related pain, axial neck pain and spinal cord symptoms arising from degenerative changes in the lower cervical spine.
The atlantoaxial joint consists of the atlanto-odontoid joint (between the dens of the axis and the anterior arch of the atlas) together with two lateral mass joints. There is no intervertebral disc between C1 and C2, and the main stabilizer of this joint is the transverse ligament of the atlas. Rotation is greatest at this segment (25–30° to each side), and because of this large range of motion and the absence of a disc, the region is vulnerable to degenerative change¹.
Atlantoaxial osteoarthritis is commonly divided into three types: idiopathic, degenerative and post-traumatic. In older patients, the condition is most often caused by degenerative disease, while in younger patients it is usually related to trauma²,³.
Clinically relevant anatomy
The atlantoaxial joint forms the connection between the atlas (C1) and axis (C2) and includes the central atlanto-odontoid joint as well as two lateral facet joints. The joints are stabilized by a capsule and several ligaments, including the strong transverse ligament, which holds the dens in place and prevents anterior subluxation toward the spinal cord. The joint primarily permits rotation, with some flexion and extension.
Epidemiology and etiology
Idiopathic osteoarthritis is most commonly seen in older adults, while post-traumatic osteoarthritis is more common in younger people. Prevalence has been estimated at between 4% and 8%⁶,⁷, and most symptomatic patients are women (approximately 74%) with unilateral involvement⁷,⁸. Pain is typically provoked by rotation and may radiate toward the occiput, temple and, in some cases, forward toward the eye⁷,⁸.
Studies show an age-related increase in prevalence, from 16% in people aged 18–25 years to more than 90% in those over 70 years⁹. Severity also increases with age. Sex does not appear to be a significant factor in the development of atlanto-odontoid osteoarthritis itself⁹,¹⁰. Patients with a previous dens fracture have a high prevalence of osteoarthritis in the atlanto-odontoid joint, while the lateral joints usually remain intact¹¹. Chronic head loading has also been identified as a risk factor for degenerative changes in the upper cervical spine¹⁰.
Characteristics and clinical presentation
The most common symptom is unilateral neck pain, which worsens with rotation or flexion of the head. Pain may radiate from the neck toward the occiput, temple and sometimes forward toward the eye⁶,⁷. Other symptoms include cervicogenic headache, occipital neuralgia and reduced mobility, particularly in axial rotation¹²,¹³.
Common clinical findings include:
Sharp unilateral neck pain with rotation
Pain radiating toward the occiput and temple
Visual symptoms that may lead to inappropriate referral to an ophthalmologist
Distinct, painful crepitus during rotation
Muscle spasms and marked restriction of movement, particularly C1–C2 rotation⁶,⁷,¹⁴
Several studies suggest that the degree of degeneration does not necessarily correlate with symptom severity. In a study by Badve et al., no significant association was found between radiological findings and symptoms in male carriers¹⁰. According to Betsch et al., degeneration in this joint is associated with dens fractures, and radiographs should therefore be carefully assessed for degenerative changes in the atlanto-odontoid and facet joints¹².
Differential diagnoses
Atlantoaxial osteoarthritis shares symptoms with both common and less common neck conditions. It is therefore important to consider a broad range of differential diagnoses, particularly in patients with unilateral occipitocervical pain, restricted movement and neurological symptoms.
Common differential diagnoses include:
Cervical sprain – often following trauma, with localized pain and muscle stiffness.
Acute whiplash – caused by acceleration-deceleration mechanisms, commonly after motor-vehicle collisions.
Less common differential diagnoses:
Rheumatoid arthritis – may also affect the atlantoaxial joint and lead to instability.
Cervical facet joint syndrome – causes pain with movement and palpation over the facet joints.
Spasmodic torticollis – characterized by involuntary contractions of the neck muscles.
Cervical fractures – for example Jefferson fracture (C1), dens fracture (C2), or Hangman's fracture.
Cervical dislocation – typically associated with high-energy trauma, deformity and neurological findings.
Cervical radiculopathy or myelopathy – may cause pain, weakness or coordination difficulties.
Cancer (primary or metastatic) – should be considered in persistent night pain or unexplained weight loss.
Meningitis – neck stiffness, fever and systemic symptoms.
Vertebral osteotomy or surgically altered cervical anatomy.
Epidural abscess – causes rapidly developing neurological symptoms and requires urgent treatment.
It is particularly important to distinguish degenerative fibrosis associated with atlantoaxial osteoarthritis from:
Rheumatoid fibrosis
Tumors (benign or malignant processes in the cervical spine)
Migrated disc herniation⁶
In older patients with neck pain and/or progressive quadriparesis, atlantoaxial osteoarthritis should be included as a possible cause. Identification of a degenerative ligamentous mass around the dens may indicate joint instability⁸.
Diagnostic procedures
Diagnosis is primarily based on a thorough clinical assessment, which includes:
History:
Pain characteristics: onset, duration, location, aggravating and relieving factors.
Previous medical conditions, medication use and family history.
Screening for red flags, such as night pain, fever and weight loss⁶,¹⁴.
Clinical examination:
Active and passive cervical range of motion, with particular focus on rotation.
Palpation of joints and musculature.
Neurological screening: reflexes, sensation and strength.
Observation of function, gait and coordination.
Assessment of pseudoclaudication and signs of spinal cord involvement¹⁴.
The diagnosis of osteoarthritis is largely clinical, but imaging is used to support the assessment and exclude other conditions (see differential diagnoses). Radiological findings, however, often correlate poorly with the patient's symptoms⁹.
Imaging includes:
X-ray (standard atlas view): may demonstrate narrowing of the C1–C2 joint space.
CT: provides detailed visualization of bony structures and is used for surgical planning or when osteophyte formation, tumor or fracture is suspected⁹,¹⁰.
MRI: is used when neurological involvement or soft-tissue pathology is suspected.
Bone scintigraphy: may show increased uptake but is not required for diagnosis.
Intra-articular C1–C2 blocks: can be used both diagnostically and for pain relief to confirm that the joint is the source of symptoms⁷.
Laboratory tests are used to exclude inflammatory conditions such as rheumatoid arthritis, as well as infection or malignancy⁶.
Outcome measures
The following standardized instruments may be used to assess function and symptom burden:
Neck Disability Index (NDI)
Bournemouth Questionnaire for the neck
Neck Pain and Disability Scale
Numeric Rating Scale (NRS)
Pain Catastrophizing Scale
Visual Analogue Scale (VAS)
These tools are useful for quantifying pain, functional limitation and psychological aspects related to the patient's experience of the condition.
Medical treatment
Treatment of atlantoaxial osteoarthritis follows a stepwise approach based on severity, functional limitations and the patient's response to conservative measures. The goals are to reduce pain, improve function and prevent progression. Conservative treatment is always the first choice, while surgery is considered only when adequate improvement is not achieved.
Injection therapy Injections of glucocorticoids into the lateral atlantoaxial joints have been shown to be effective in patients who do not obtain sufficient relief from conventional non-invasive treatment¹⁶. Intra-articular injections may reduce local inflammation and pain and are particularly considered in pronounced unilateral pain with clear movement-related aggravation.
Pharmacological treatment
Gabapentin may be useful particularly when occipital neuralgia is present, involving irritation of the greater or lesser occipital nerve. It provides analgesia by modulating neuropathic pain.
Other pharmacological options include:
NSAIDs at higher doses for short-term anti-inflammatory effect
Muscle relaxants to reduce spasms
Tricyclic antidepressants such as amitriptyline for chronic pain
Prednisolone for marked inflammation
Short-term use of weak opioids when other treatment does not provide adequate relief⁸
These medications are selected individually based on patient tolerance, comorbidities and treatment response.
Surgical treatment If conservative measures do not provide a satisfactory result and the patient has substantial functional impairment or pain,surgical stabilization in the form ofposterior C1–C2 fusion may be considered. This involves fusion of the two uppermost cervical vertebrae using screws and rods.
A meta-analysis has shown that posterior fusion is bothsafe and effective, with a low complication rate and a high rate of successful fusion (arthrodesis)⁹.
In a retrospective study by Grob et al., 89% of patients reported pain reduction and 85% stated that they would undergo the operation again⁷.
Another method involves a polyaxial screw-rod system, which allows temporary fixation and possible reduction after placement. This provides surgical flexibility while preserving as much anatomical integrity as possible¹⁶.
Physiotherapy
Physiotherapy management of atlantoaxial osteoarthritis is multifaceted and individualized. The aims are to:
reduce pain
increase mobility
improve stability and function
prevent progression
General principles:
Early mobilization after diagnosis is recommended, but the patient should haveat least 48 hours of relative rest during an acute pain episode¹⁴.
Treatment should be gentle and focus on afunctional approach.
Interventions may include:
Specific neck-stabilization exercises targeting the deep flexors and scapular control
Manual therapy: cautious mobilization of the cervical spine, particularly away from painful directions. Manipulation should be considered carefully and avoided when instability is suspected.
Local treatment of trigger points using infrared therapy or TENS.
Low-level laser therapy andpulsed electromagnetic field therapy may be considered for chronic pain when traditional measures have had limited effect.
Intermittent traction may help reduce pain and improve movement.
Shortwave therapy anddry heat therapy may provide symptomatic relief for muscle tension and inflammation¹⁴,¹⁰,¹¹,¹²,¹⁵.
Evaluation of treatment progress:
Regular reassessment using selectedoutcome measures such as the NDI or VAS is recommended.
If progress is inadequate, further referral for injection therapy or surgical assessment should be considered.
Exercise programs
Supportive neck exercise is particularly effective for mechanical neck disorders, both with and without associated headache. In atlantoaxial osteoarthritis, which often involves unilateral cervicogenic pain and reduced rotational mobility, combining manual therapy with active exercise is recommended for the best possible outcome. A systematic review by H. Sarig Bahat reports relatively strong evidence for proprioceptive exercises and dynamic strengthening of the neck-shoulder musculature in chronic or recurrent neck complaints¹⁴.
A frequent contributor to neck pain istrapezius myalgia, particularly involving the upper trapezius. Targeted exercises for this muscle have shown beneficial effects and require only simple training equipment. The exercises should be performed with controlled movement and without rapid acceleration. Raise and lower the weight smoothly over approximately three seconds per repetition. The patient should use a load corresponding to about an 8-repetition maximum (approximately 80% of 1RM)⁷.
Combined strength and endurance training for thecervicoscapulothoracic and shoulder-related musculature may help reduce pain and improve function. Stretching exercises alone, however, do not appear to have a documented effect for this type of complaint¹⁶.
An effective exercise program should contain at least two sets of three repetitions per exercise (six repetitions in total), with two minutes of rest between sets to avoid muscular fatigue⁷. All exercises are performed with loads corresponding to an 8-repetition maximum.
Examples of exercises to reduce tension in the upper trapezius:
1. Shrugs (SHR):
Starting position: Stand upright with dumbbells hanging by the sides.
Movement: Elevate the shoulders as high as possible while actively contracting the upper trapezius.
2. One-arm rows (ONE):
Starting position: Lean the trunk approximately 30 degrees from horizontal. Support the body with one arm and one knee on a bench while the other foot remains on the floor.
Movement: Pull the dumbbell toward the lower ribs on the same side while keeping the trunk stable.
3. Upright rows (UPR):
Starting position: Stand upright with the dumbbells hanging in front of the body.
Movement: Lift the dumbbells vertically along the body toward the chest, with the elbows moving outward and upward into abduction.
4. Reverse flys (REV):
Starting position: Lean forward at approximately 45 degrees from horizontal with the arms hanging toward the floor.
Movement: Raise the dumbbells out to the sides until the upper arms are horizontal. Keep the elbows slightly flexed (approximately 5°) throughout the movement.
5. Lateral raises (LAT):
Starting position: Stand upright with the dumbbells hanging by the sides.
Movement: Abduct the shoulders until the upper arms are horizontal, keeping the elbows slightly flexed (approximately 5°) throughout the lift.
These exercises can be used alone or integrated into a multidisciplinary treatment program to improve stability, proprioception and load tolerance in the neck-shoulder region. Close physiotherapy follow-up is recommended, with assessment of pain response and movement quality throughout the rehabilitation process.
Manual therapy – manipulation and mobilization
There is strong evidence that manual therapy alone is not significantly more effective than other approaches such as exercise, physiotherapy, medication or shortwave diathermy for relieving neck pain⁸. However, studies show that patients receiving manual therapy are often more satisfied with treatment than those receiving a single treatment modality. Three independent studies have identified a trend toward greater improvements in pain, disability and patient-perceived recovery when manual therapy is combined with exercise rather than used alone.
Mobilization and/or manipulation combined with exercise is particularly effective for persistent mechanical neck disorders, both with and without headache¹⁶. Manual therapy alone is generally insufficient for long-term functional improvement, whereas combining it with exercise can provide significant benefits in pain reduction, function and global perceived effect.
A case series by Yu H et al. suggests that symptoms of atlantoaxial osteoarthritis may improve with upper-cervical manipulation combined with mobilization using a mechanical device known as theS.M.A.R.T. Adjuster. This is an articulated mechanical device that uses a pressure sensor to identify tissue changes associated with reduced segmental movement. The device can deliver force impulses of up to 20 lb/inch² using a piezoelectric pressure sensor, with the aim of mobilizing the joints. Treatment was individualized according to patient age, cause of the condition, duration, symptom pattern and tolerance of manipulation⁶. Early in symptom development or soon after injury, treatment was generally delivered at higher frequency and lower intensity. Once symptoms stabilized, frequency was reduced, for example to once per week.
High-velocity, low-amplitude (HVLA) manipulation of the upper cervical spine has been reported to increase facet-joint space and improve mobility. This may reduce pain associated with degeneration and potentially slow further degenerative change¹⁰. Such manipulation must only be used in patients without neurovascular deficits and without signs of acute injury.
After upper-cervical HVLA manipulation, supplementary mobilization of the same region has been recommended to help maintain and extend treatment gains. In atlantoaxial osteoarthritis, manual therapy should be performed with considerable caution and combined with a structured exercise program to optimize function, reduce pain and support patient satisfaction.
Low-level laser therapy and other physical modalities
Low-power laser therapy (LPLT) has shown promising results for pain and disability in cervical osteoarthritis, including atlantoaxial osteoarthritis. In a study by Ozdemir et al., LPLT was compared with placebo in 60 patients. Significant improvements were reported in pain, paravertebral muscle spasm, lordosis angle, neck mobility and overall function in patients receiving laser therapy, while the placebo group showed no improvement¹²,¹⁴. This suggests that LPLT may be a gentle and potentially effective option for pain relief and functional improvement in osteoarthritic conditions, although the mechanisms require further research.
Monteforte et al., however, did not find significant pain reduction after 20 days of treatment but observed a significant reduction in the thickness of the subcutaneous tissue layer over the trapezius muscle, which may indicate reduced muscle tension¹¹
. Although the study did not confirm immediate pain reduction, the findings suggest that LPLT may have structural effects on muscle tissue.
Pulsed electromagnetic fields (PEMF) are another modality used in the treatment of cervical osteoarthritis. PEMF generates a pulsed electromagnetic field that may stimulate collagen production and support chondrocyte activity. In a study by Sutbeyaz ST, patients lay on a PEMF mat for 30 minutes twice daily for three weeks. Treatment produced a significant reduction in pain, improved flexion and extension, and reduced paravertebral muscle spasm¹⁴. Another study by Trock et al. found significantly greater improvements in pain and range of motion in the experimental group compared with placebo, both immediately after treatment and one month later¹¹.
Infrared stimulation of local trigger points has also been shown to provide short-term pain relief. This form of heat therapy specifically targets areas of increased muscle tone. A systematic review by Chow et al. analyzing randomized controlled trials found that four of five studies reported significant positive effects on neck pain using infrared treatment at wavelengths between 780 and 1064 nm¹⁵. Despite the absence of standardized treatment protocols, the results suggest a clinically relevant effect, particularly in the acute phase or as an adjunctive intervention.
Short-term benefits of physiotherapy for degenerative spinal disorders were also reported by Hey et al., including significant improvements in activities such as sleeping, writing, housework and lifting heavy objects. Treatment consisted of joint mobilization, heat therapy, traction, shortwave therapy and interferential current therapy¹⁰.
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