Pavlov's ratio from plain radiographs in patients with neck pain but no radicular symptoms was compared with the areas of the cervical spinal cord and cerebrospinal fluid column on magnetic resonance scans.The area of the cervical canal or cord obviously depends on both the sagittal and transverse diameters. Although the pathology in stenosis of the cervical spine is mainly in the sagittal plane, narrowing only in the sagittal diameter may not indicate significant reduction in the area of the canal. The transverse area of the cord has been shown to correlate well with the pathologic changes of the cord in cervical myelopathy. We correlated Pavlov's ratio on the plain radiographs to the area of the cerebrospinal fluid column and the area of the cord on the magnetic resonance scan.We examined the lateral radiographs and axial and sagittal T2-weighted magnetic resonance scans in the neutral position of the cervical spine (C4-C7) of 87 patients with 332 levels with neck pain but no radicular symptoms and normal magnetic resonance scans. On the magnetic resonance images, the sagittal diameters of the cerebrospinal fluid column and the cord were measured at the midvertebra level on T2 sagittal images from C4 to C7. From the T2 axial images, the area of the cord and the area of the cerebrospinal fluid column were measured at the same levels.The correlation between Pavlov's ratio and the area of cerebrospinal fluid column was moderate, with the highest value of 0.31 at C5. The sagittal diameter of the cerebrospinal fluid column showed variable correlation with the area of the cerebrospinal fluid column. The highest correlation was 0.68 between the sagittal diameter and the area of the cerebrospinal fluid column at C7. The correlation between Pavlov's ratio and the area of the cord is around zero, with the highest correlation of 0.21 at C4. The sagittal diameter of the cord showed a moderate correlation with the area of the cord.This study shows a poor correlation between Pavlov's ratio and the space available for the cord. Therefore, this ratio cannot be solely relied upon to predict the area changes in that plane of the cervical spinal canal.
Anterior cruciate ligament injury increases risk for accelerated development of osteoarthritis. The effect of exercise on articular cartilage following joint injury is not well understood. Biochemical biomarkers of collagen degradation and proteoglycan turnover are potential indicators for early articular cartilage degeneration.This study tests the hypothesis that serum concentrations of CS846 and CTXii correlate with structural changes to articular cartilage following joint injury in exercised animals.Controlled laboratory study.Twenty-four Sprague-Dawley rats underwent either arthrotomy alone (sham surgery) or anterior cruciate ligament transection (ACLT). Animals were recovered for 3 weeks and then exercised on a treadmill at 18 m per minute, 1 hour per day, 5 days per week, until sacrifice either 6 or 12 weeks later. Articular cartilage was assessed grossly, and histology was graded using modified Mankin, toluidine blue, and modified David-Vaudey scales. Serum collected preoperatively and at sacrifice was assayed by ELISA for CTXii and CS846.At 6 weeks, gross grades (P < 0.01), modified Mankin scores (P < 0.03), and toluidine blue scores (P < 0.04) were higher, reflecting increased degeneration in ACLT animals compared with sham surgery animals. Serum CS846 increased after 6 weeks in ACLT animals (P < 0.05). Serum CTXii levels strongly correlated with Mankin degenerative scores (coefficient = 0.81, P < 0.01) and David-Vaudey histology grades (coefficient = 0.73, P < 0.01) at 6 weeks. While gross grades remained higher at 12 weeks in ACLT animals (P < 0.04), no differences were seen in serum CS846 and CTXii. Histology scores also showed no differences between ACLT and sham due to increasing degeneration in the sham surgery group.The strong correlation between serum CTXii and microstructural changes to articular cartilage following joint injury demonstrates potential use of serum biomarkers for early detection of cartilage degeneration. Increasing cartilage degeneration in exercised sham-surgery animals suggests that early loading may have negative effects on articular cartilage due to either mechanical injury or hemarthrosis after arthrotomy.Patients with anterior cruciate ligament injury are at increased risk for development of posttraumatic osteoarthritis. CTXii may be useful for early detection of joint degeneration. Further study on the effects of exercise after injury is important to postinjury and postoperative rehabilitation.
