577

BRIEF REPORT

ATLANTOAXIAL (C 1-C2) FACET JOINT OSTEOARTHRITIS: A DISTINCTIVE CLINICAL SYNDROME

JAMES T. HALLA and JOE G. HARDIN, JR.

Osteoarthritis of the atlantoaxial facet joints was identified radiologically in 27 patients, and these com- prised 4% of all outpatients with osteoarthritis or degenerative disease of the spine seen during a 36-month period. These patients had a clinical syndrome which differed from those seen in patieots who have subaxial degenerative disease of the spine or myofascial cervical pain. Occipital pain, occipital trigger points, crepitus in the occipital region, and a rotational head tilt deformity (in 13 patients, usually associated with collapse of 1 of the lateral masses [facets]), were the major features of this distinctive syndrome.

Degenerative joint disease of the cervical spine (DJCS) occurs both at the synovial or apophyseal articulations (osteoarthritis; OA) and at the cartilagi- nous or intervertebral disc joints (osteochrondrosis or spondylosis deformans). The disease predominates in the middle and lower cervical regions, where it may be associated with neck, shoulder girdle, or arm symp- toms (1-3). OA of the apophyseal or facet joints of the atlantoaxial (C 1-C2) articulation has received little scientific attention, though these joints are frequently affected by the inflammatory arthropathies (43). We have described a distinctive clinical syndrome which results from Cl-C2 facet joint OA (6). The present study was designed to determine the frequency of

James T. Halla, MD, Abilene, Texas; Joe G. Hardin, Jr., MD: Professor of Medicine, University of South Alabama College of Medicine, Mobile, Alabama.

Address reprint requests to Joe G. Hardin, Jr., MD, Uni- versity of South Alabama College of Medicine, 2451 Fillingim Street, Mobile, AL 36617.

Submitted for publication May 5 , 1986; accepted in revised form November 5, 1986.

symptomatic Cl-C2 OA and the specificity of its clinical manifestations.

PATIENTS AND METHODS

Patients. The study population consisted of 705 outpatients seen consecutively over a 36-month per- iod. Six hundred twenty-five had radiologically docu- mented peripheral OA or degenerative joint disease of the spine (DJS), and 80 had neck or shoulder girdle pain with normal findings on cervical spine radio- graphs and no clinical evidence to suggest peripheral OA. All patients with documented OA or DJS, or with neck or shoulder girdle pain who were seen during this period were included in the original study group of 705. None of these patients had a clinically evident inflammatory arthropathy and none had radiologic evidence of chondrocalcinosis.

Cervical spine radiographs, including an ade- quate open-mouth view of Cl-C2, were available for 252 of these patients, including all with cervical or shoulder girdle symptoms. Twenty-seven of the radio- graphs demonstrated Cl-C2 facet joint OA. To define the specificity of the clinical manifestations of Cl-C2 OA, the remaining 225 patients on whom adequate cervical radiographs were available were assigned to the following mutually exclusive control groups: group 1-patients with peripheral OA or DJS seen radiologi- cally, but who had no neck complaints (n = 75); group 2-patients with neck or shoulder girdle symptoms and subaxial (only) DJCS (n = 50); and group 3-100 consecutive patients (excluding those with C 1-C2 OA) who were entered into a prospective phase of this study because of their neck and shoulder girdle symp-

Arthritis and Rheumatism, Vol. 30, No. 5 (May 1987)

578 BRIEF REPORTS

Table 1. Cervical radiologic features of 27 patients with CI-C2 facet joint osteoarthritis (OA)*

Neck position

(rotational C1-C2 facet jbint OA Lateral mass collapse; Rotatory Lateral Subaxial

Patient Site Severity f tilt) predominant side subluxation subluxation DJCS

1 2 3 4 S 6 7 8 9

10 11 12 13 14 1s 16 17 18 19 20 21 22 23 24 25 26 27

L > R L > R L > R R > L L > R L L R L L L > R R R > L L > R R R R R R = L R L L R L L L R

severe Severe Moderate Severe Severe Moderate Moderate Severe Minimal Minimal Severe Moderate Severe Moderate Severe Severe Minimal Moderate Severe Minimal Minimal Minimal Minimal Minimal Minimal Minimal Minimal

L; NR L; NR L; Rev R; NR L; Rev Normal Normal R; Rev Normal Normal Normal Normal R; NR Normal R; Rev R; Rev Normal R; Rev R; NR Normal Normal L; Rev Normal Normal L; Rev Normal Normal

Yes. L Yes, L No Yes, R Yes, L No No No No No Yes, L No Yes, R No No Yes, R No No Yes, R = L No No No No No No No No

Yes Yes N o Yes No No No No No No No No Yes No No No No No Yes NA N o NA NA No No NA No

Yes Yes No Yes Yes No No N o No N o N o No Yes N o No No N o Yes Yes NA No NA NA No N o NA No

Moderate None Moderate Minimal Minimal Minimal Minimal Minimal Minimal Severe Minimal None None Moderate Minimal None Moderate Moderate Moderate Minimal Minimal Minimal None None Moderate Moderate Moderate

* DJCS = degenerative joint disease of the cervical spine; L = left; R = right; NR = nonreversible; Rev = reversible; NA = data not available (tomo,graphy not done). t See text for definitions.

toms, with (n = 20) or without (n = SO) subaxial DJCS. So that all the available radiologic data could be used, no attempt was made to age- or sex-match these 3 groups with the CLC2 OA group.

Clinical evaluation. All patients with C 1-C2 OA and those in the 3 control groups were questioned concerning location and duration of neck and shoulder girdle pain. Head position was noted, and active and passive cervical ranges of motion were estimated. The neck region and shoulder girdle were palpated for tender or trigger points, and the presence of audible or palpable crepitus was recorded.

Radiologic evaluation. Lateral and open-mouth C 1 Z 2 projections of the cervical spine were obtained from all patients with CLC2 OA and from all of the controls. Cervical tomography was performed on pa- tients in whom the C1-C2 facet joints could not be adequately visualized on the open-mouth view; this included all but 4 of the patients with C1-C2 OA (patients 20, 22, 23, and 26). OA was defined and

graded as minimal, moderate, or severe, according to the following standard radiologic criteria (2): I ) osteophyte formation; 2) periarticular ossicles (mainly in small hand joints); 3) joint space narrowing with sclerosis of subchondral bones; 4) subchondral cysts; and 5 ) altered shape of bone end. One point was assigned to each criterion. A score of 0-1 = doubtful OA (patients with doubtful OA were not included in this study); 2 = minimal OA; 3 = moderate OA; and 4 = severe OA.

Lateral subluxation at C1-C2 was considered to be present if the lateral masses (articular facets) were laterally displaced by more than 2 mm in relation to each other. Rotatory subluxation at Cl-C2 was de- fined according to the criteria of Fielding and Hawkins: forward rotation of I lateral mass, causing it to appear wide and close to the midline, and backward rotation of the other lateral mass, causing it to appear narrow and removed from the midline (7). Atlantoaxial lateral mass collapse has been defined previously ( 4 3 .

BRIEF REPORTS 579

Figure 1. Anteroposterior tornogram of the Cl-C2 region in patient 4. Lateral mass collapse predominates on the right, but there is lateral subluxation ta the left.

RESULTS

Twenty-seven patients (4% of all patients with OA or DJS; 11% of patients on whom cervical spine radiographic data were studied) had at least minimal C1-C2 facet joint OA. The mean age of these patients was 75.6 (range 58-84). Twenty were women. The mean duration of neck symptoms was 7.6 years (range 0.5-30). Most patients had evidence of OA at sites other than the neck, and 5 had generalized disease (4 or more joints).

All 27 patients gave a history of neck pain; in all but 4, the pain was intermittent. The pain was located predominantly in the occipital region in all 27 patients; 7 also complained of postauricular pain. Symptoms were generally considered to be moderate or severe. Ten patients interpreted their pain as a headache. No patient described a radicular pain, and none had symptoms suggestive of a myelopathy.

A rotational head tilt deformity was observed in 13 patients, but it was actively or passively reversible in all but 5. Lateral flexion of the neck was usually normal to mildly reduced, but all patients had reduced active and passive head rotation. Tender or trigger

points were identified in the occipital region in all patients and were bilateral in 1 1. Tenderness or trigger points over the upper border of the trapezius were less prominent, but were found in 12 patients. All patients had crepitus which was palpable over the upper part of the neck; in 6, the crepitus was audible to the examiner.

Radiologic features of the cervical OA are listed in Table 1. Figures 1-3 show tomograms from patients 4, 1 I , and 16, respectively. The open-mouth view of the Cl-C2 region was usually adequate for demon- strating the Cl-C2 OA, but plain tomography permit- ted better definition of the derangement. Absence of tomographic data did make it dificult to define subluxations at Cl-C2 with certainty, but the 4 pa- tients who did not have tomograms had mild Cl-C2 OA, and it was unlikely that they had subluxations. The atlanto-occipital joint was evaluated tomograph- ically in 23 patients and was normal in all but 1, in whom the involvement was unilateral and minimal. No effort was made to interpret degenerative changes of the atlanto-odontoid articulation, but the odontoid process was grossly normal in all of the subjects who had tomography.

BRIEF REPORTS

Figure 2. Anteroposterior tomogram of the Cl-C2 region in patient 1 1 . Lateral mass collapse predominates on the left.

The Cl-C2 facet joint OA was most often moderate or severe. The process was predominantly unilateral in all but 9 patients, and was perfectly symmetric in only 1. Cl-C2 lateral mass collapse was found in 8 patients, and it was predominantly uni- lateral in 7. The patient with symmetric collapse had a nonireversible rotational head tilt to the right, and 6 of the remaining 7 patients had rotational tilt to the side of the most collapsed mass. The tilt was passively reversible in 2 of these patients, however. Six other patients who did not have lateral mass collapse also had reversible head tilt deformity. Rotatory and lateral C 1-C2 subluxation generally occurred together, and both tended to occur in patients with lateral mass collapse. Subaxial OA was noted in 21 patients, but was severe in only 1.

Because of intractable pain, occiput-C2 cervi- cal fusion was performed on 1 patient (patient 5 ) , with

partial relief of pain resulting. Patient 4 became asymptomatic with no therapy, but the abnormal head position persisted. The other patients have been treated conservatively (gentle cervical traction, trigger point injections, and/or analgesic or nonsteroidal antiinflammatory drugs), with partial relief of pain. None has developed neurologic symptoms or signs.

Findings in the 3 control groups are summa- rized in Table 2. All control patients (by definition) had normal C 1-C2 articulations. None had predominantly occipital or posterior auricular pain. The limited neck mobility found in 4 patients primarily involved lateral flexion. None of the control patients had an abnormal head position. Tender or trigger points were found mainly in group 3 patients, and most of these patients were considered to have myofascial pain. The trigger points were equally distributed among the posterior cervical region (including the occiput), the upper bor- der of the trapezius, and the medial scapular border; in no patient were they confined to the occipital region. Crepitus was not detected in any of the control pa- tients.

DISCUSSION

Our findings suggest that OA of the Cl-C2 facet joint is not rare; it occurred in a symptomatic form in 4% of a population with peripheral OA or DJS. This study was not designed to determine the frequency of asymptomatic Cl-C2 OA; however, it is noteworthy that asymptomatic Cl-C2 OA was not seen in any of the 75 OA or DJS patients without neck pain, who received cervical roentgenography for purposes of this study or for the evaluation of shoulder girdle or arm pain. Furthermore, our results suggest that C1-C2 facet joint OA tends to produce a distinctive clinical syndrome different from those associated with subaxial DJCS alone or with myofascial cervical pain. The Cl-C2 facet joint OA syndrome occurs mainly in elderly women who have OA or DJS at other sites. The major symptom is occipital and postauricular pain. Distinctive physical signs include limited head rotation, tender or trigger points confined to the oc- cipital area, palpable cervical crepitus, and abnormal head position.

Nonreducible rotational head tilt associated with C 1-C2 lateral mass collapse predominating on the side of the tilt has been described in patients with adult rheumatoid arthritis, juvenile rheumatoid arthritis, and ankylosing spondylitis (43) . It is apparent that this phenomenon may also result from OA, though the

BRIEF REPORTS 58 1

Figure 3. Anteroposterior tomogram of the C1-C2 region in patient 16. Degenerative changes and lateral mass collapse are apparent only on the right.

cause of the bone collapse is unclear. Mechanical factors are probably more important than erosive synovitis in the lateral mass collapse of OA. The association of lateral mass collapse with nonreducible rotational head tilt also seems to be less constant in OA than in the inflammatory arthropathies. In our study, only 5 of 8 patients with lateral mass collapse had a nonreducible head deformity.

Cl-C2 OA has been discussed in 2 previous reports. Harata et a1 (8) described 31 patients with

Table 2. Clinical and radiologic features of the control groups*

radiographically evident Cl-C2 OA and neck or shoul- der girdle symptoms. They distinguished between the atlantoaxial disease described in the present report and atlanto-odontoid disease not specifically ad- dressed in our study; however, atlantoaxial or mixed lesions were most often found. Prost and colleagues reported 3 cases of unilateral erosive Cl-C2 facet joint OA with radiographic changes similar to those seen in erosive OA of the small joints of the hand (9).

It is not clear why the syndrome of Cl-C2 facet

Group (n) Primary diagnosis Cervical radiographs Cervical pain Cervical range of motion Trigger points Crepitus

I (75) DJS and peripheral Normal C1-C2 articulation; OA subaxial DJCS (usually

minimal)

subaxial DJCS (all patients)

2 (50) Subaxial DJCS Normal C I-C2 articulation;

3 (100) Myofascial neck and Normal CI-C2 articulation; shoulder girdle otherwise usually normal pain (90 patients)

None Normal None None

Diffuse cervical pain Decreased lateral flexion Diffuse cervical None and stiffness and/ (2 patients) ( I patient) or diffuse shoul- der girdle pain

shoulder girdle (2 patients) shoulder girdle pain (90 patients)

Diffuse cervical and Decreased lateral flexion Diffuse cervical and None

* DJS = degenerativejoint disease of the spine; OA = osteoarthritis: DJCS = degenerative joint disease of the cervical spine.

BRIEF REPORTS

joint OA has not been more widely recognized. In some cases the severity of the peripheral OA might detract from the neck symptoms, but most of our patients emphasized their cervical pain. Many of our patients referred to their symptoms as a “headache,” suggesting that the location of the symptoms might mislead physicians who are unfamiliar with this syn- drome. Cl-C2 OA is not readily apparent on routine lateral and posteroanterior views of the cervical spine; its I ecognition usually requires at least an adequate open-mouth view of Cl-C2. This latter view has not been a traditional focal point when OA is the sus- pected diagnosis, and it is likely that the Cl-C2 OA is often simply overlooked.

There is no apparent specific therapy for Cl-C2 facet joint OA. None of our patients developed neurologic indications for surgery, but a cervical fu- sion was performed on 1 patient because of intractable pain, and partial symptomatic relief resulted. Based on this limited experience, the role of surgery in this situation cannot be commented upon. During exacer- bations, most of our patients responded satisfactorily to conservative maneuvers. These included gentle cervncal traction, trigger point injections, nonsteroidal antiinflammatory drugs, and simple analgesics. Recog- nition of this specific syndrome is more important for purposes of reassurance to the patient than for pur- poses of specific therapy.

REFERENCES

1. Resnick D, Niwayama G: Degenerative disease of the spine, Diagnosis of Bone and Joint Disorders with Em- phasis on Articular Abnormalities. Vol. 11. First edition. Edited by D Resnick, G Niwayama. Philadelphia, WB Saunders, 1981, pp 1368-1415

2. Brandt KD: Osteoarthritis: clinical patterns and pathol- ogy, Textbook of Rheumatology. Vol. 11. Second edition. Edited by WN Kelley, ED Hams Jr, S Ruddy, CB Sledge. Philadelphia, WB Saunders, 1985, pp 1432-1448

3. Jeffreys E: Cervical spondylosis, Disorders of the Cervical Spine. First edition. Edited by E Jeffreys. Lon- don, The Butterworth Group, 1980, pp 90-105

4. Halla JT, Fallahi S, Hardin JG: Nonreducible rotational head tilt and lateral mass collapse: a prospective study of frequency, radiographic findings, and clinical features in patients with rheumatoid arthritis. Arthritis Rheum 25:1316-1324, 1982

5. Halla JT, Fallahi S, Hardin JG: Nonreducible rotational head tilt and atlanto-axial lateral mass collapse. Arch Intern Med 143:471474, 1983

6. Halla JT, Fallahi S, Hardin JG: Atlanto-axial (CI-Cz) facet joint osteoarthritis with and without non-reducible rotational head tilt (abstract). Arthritis Rheum (suppl) 28:S21, 1985

7. Fielding J, Hawkins R: Atlanto-axial rotatory fixation. J Bone Joint Surg 59A:3744, 1977

8. Harata S, Tohno S, Kawagishi T: Osteoarthritis of the atlanto-axial joint. Int Orthop 5:227-282, 1981

9. Prost G, Tanguy G, Audrian S, Cottin S, Calvez A, Elie JP: Arthroses erosives atloido-axoidiennes. Rev Rhum Ma1 Osteoartic 49:365-369, 1982