Early detection of developing osteoarthritis by scintigraphy: an experimental study on rabbits

Association of bone scintigraphic abnormalities with knee malalignment and pain

OBJECTIVE

The information content of knee bone scintigraphy was evaluated, including pattern, localisation and intensity of retention relative to radiographic features of knee osteoarthritis, knee alignment and knee symptoms.

METHODS

A total of 308 knees (159 subjects) with symptomatic and radiographic knee osteoarthritis of at least one knee was assessed by late-phase (99m)Technetium methylene disphosphonate bone scintigraph, fixed-flexion knee radiograph, full limb radiograph for knee alignment and for self-reported knee symptom severity. Generalised linear models were used to control for within-subject correlation of knee data.

RESULTS

The compartmental localisation (medial vs lateral) and intensity of knee bone scan retention were associated with the pattern (varus vs valgus) (p<0.001) and severity (p<0.001) of knee malalignment and localisation and severity of radiographic osteoarthritis (p<0.001). Bone scan agent retention in the tibiofemoral, but not patellofemoral, compartment was associated with severity of knee symptoms (p<0.001) and persisted after adjusting for radiographic osteoarthritis (p<0.001).

CONCLUSION

To the authors' knowledge, this is the first study describing a relationship between knee malalignment, joint symptom severity and compartment-specific abnormalities by bone scintigraphy. This work demonstrates that bone scintigraphy is a sensitive and quantitative indicator of symptomatic knee osteoarthritis. Used selectively, bone scintigraphy is a dynamic imaging modality that holds great promise as a clinical trial screening tool and outcome measure.

An experimental study of new diagnostic methods for the examination of osseous lesions in the temporomandibular joint

Digital subtraction radiography, tomosynthesis, bone uptake of radionuclide, and arthroscopy were evaluated for detection and quantification of bony lesions induced unilaterally in the condyles of six dogs. A stereotaxic head-holder facilitated acquisition of reproducible radiographs suitable for subtraction and for circular tomosynthesis. Bone uptake of technetium-99m methylene diphosphonate was measured with a hand-held collimated miniature detector. Arthroscopy was performed with an arthroscope of 2.4 mm diameter. Bone defect mass determined by subtraction radiography correlated highly (r = 0.92, p less than 0.001) with the calcium content of removed bone measured by atomic spectroscopy. Both subtraction radiography and tomosynthesis indicated reshaping of the condyle into a more anterior position over a 10-week follow-up period. Radionuclide uptake was significantly elevated (p less than 0.04) from 2 to 10 weeks after surgery and correlated (r = 0.73, p less than 0.05) with regained bone mass measured by subtraction radiography. Arthroscopy revealed progressive degeneration of cartilage with denudation in the fossa. Both radiographic techniques demonstrated the lesions and bone remodeling, but only subtraction provided quantitative results. Radionuclide uptake predicted quantitatively future bone mass changes, and arthroscopy revealed cartilage and soft tissue status not otherwise observable.

Experimental models of osteoarthritis: the role of immobilization

Evidence is reviewed from animal experiments supporting the hypothesis that immobilization, for whatever reason, is one of the pathogenetic factors in musculo-skeletal degeneration. It shows beyond reasonable doubt that immobilization is not only a cause of osteoarthritis but that it delays the healing process.