Abstract
Aims:
The interposition arthroplasty using dura mater has been applied by us as an alternative method to implantation of the prosthesis since 1997. This new surgical method was developed on the basis of ulnohumeral arthroplasty according to Kashiwagi to aspire to preserve the integrity of the joint. We used for interposition instead of lyophilized dura mater the Tutoplast° dura graft, which is treated with osmotic solvent and in this way differs from the lyophilised graft, as its tensile and pulling strength is greater, since it preserves its collagen structure and its three-dimensional fibrin structure.
Material and methods:
The dura mater interposition was applied with 23 patients in 24 cases (one bilateral), from May 1997 up to July 2000, in 17 occasions on the dominant side. The average age of the patients was 52. 2 years (24–75 years). The basic diagnosis was rheumatoid arthritis in 83. 3 percent, juvenile chronic arthritis in 8. 3 percent and post-traumatic osteoarthritis in 8. 3 percent. All the patients appeared at the follow up examination and the average duration of the follow-up was 26. 6 months (from 8 to 45 months). The clinical evaluation was based on the Mayo performance score.
Results:
Praeoperatively 71 percent of the twenty four patients had severe pain, while none of them had it at the follow up examination. 50 percent of patients were painless, 29. 2 percent had moderate and 21 percent of them had mild pain. The average decrease of point of Mayo performance score for pain was 5. 8 points, the difference is significant (p< 0. 001).
Increase of range of movement is also remarkable. Praeoperatively only 4. 2 percent of the twenty four patients had an arc of 100 degrees or more, at the follow up examination this proportion improved to 66. 7 percent. Mean value of the increase was 28. 5 degrees, the difference is significant (p< 0. 001). Range of motion of supination and pronation improved significantly (p< 0. 001).
Sixty seven percent of our patients were stable prae-operatively, this value decreased to 50 percent at the follow up. Grossly instability was observed 21 percent praeoperatively and 33 percent at follow up examination. Mean decrease of stability was 4. 2 degrees, the difference is significant (p< 0. 026). We have to notice at the same time that five of the eight grossly unstable patients had the same measurement of instability prae-operatively too, two had moderate instability and only one of them was stable before operation.
The quality of life – as far as the basic vital functions are concerned- improved with 91. 6 percent. It is very important to notice at the evaluation of Mayo performance score that 95. 8 percent of patients falled to the group with poor classification before operation, but this value decreased to 12. 5 percent at the follow up, moreover 50 percent of patients had excellent and 79. 2 percent had excellent or good classification. Mean increase of Mayo performance score evaluated to 53. 2 points, the difference is significant (p< 0. 001).
Conclusion:
One of the most serious complication of interposition arthroplasties is the absorption of the bone structures. Hence we mainly observed the radiological signs of this and employed the evaluation method of Ljung et al. reported by them in 1996. We observed the measurement of absorption of the trochlea with anteroposterior radiographs and the thinning of the olecranon with lateral radiographs. Ljung et al performed 35 joint preserver interposition arthroplasties with collegene membrane and observed 8 millimeters bone loss of humeral and 5 millimeters bone loss of ulnar part of the elbows. In our patient’s material the absorption of the trochlea occured in 33. 3 percent, in 5 occasions it was partial, and in 1 case in full degree. The rate of the partial absorption was 2. 2 mm on average. Thinning of the olecranon happened in 12. 5 percent, its average degree was 1. 6 mm. Consequently the value of the partial absorption is smaller in the case of trochlea and of the ulna too, like it was reported by Ljung et al.
On the basis of the short-term clinical and radiological results the interposition using dura mater as an alternative way to the implant arthroplasty, may be applied with good results.
