Daniel Muder: Finger Joint Reconstruction with Rib Perichondrium

Abstract

Difficulties in repairing and reconstructing articular cartilage damaged by trauma or disease remain unsolved and are one of the major challenges confronting orthopedic and hand surgeons in their clinical work. Relevant research has not adequately described the long-term clinical results, nor has it made a direct comparison to implant surgery after finger joint reconstruction with rib perichondrium. The role of the transplanted perichondrium and the resulting tissue's quality after transplantation have not been detailed with methods investigating gene and protein expression. Therefore, the overall aim of this thesis was to investigate the role and suitability of perichondrium transplants for finger joint reconstruction of cartilage defects and its potential for the field of tissue engineering.

Study I is a longitudinal cohort study to evaluate the long-term clinical outcome of finger joint reconstruction with perichondrium transplants. The study cohort included all 11 traceable and alive patients after a median follow-up of 37 (range 34-41) years. The clinical results regarding range of motion, grip strength, pain and scores on the disability of the arm, shoulder, and hand (DASH) were good to excellent without any donor site morbidity. Study II is a retrospective cohort study evaluating 163 joints in 124 patients, divided into 138 surface replacement (SR) implants in 102 patients and 25 perichondrium transplants in 22 patients. The median follow-up was 6 years for the SR group and 26 years for the transplant group. Revision rates and 10-year survival favored patients treated with perichondrium transplants, but below the threshold of statistical significance. Study III is an in vitro study to develop highly sensitive and specific protocols for immunohistochemistry, immunofluorescence, and in situ hybridization on bone tissue. The protocol modifications in this study represent critical steps that can empower highly sensitive and specific mRNA and protein localization in formalin-fixed and decalcified skeletal tissues needed for study IV. In Study IV, an experimental animal study, perichondrium transplants from enhanced green fluorescent protein (EGFP) positive rats were transplanted to wild type recipients. The reconstructed cartilage's cellular contribution and quality were assessed by immunohistochemistry, immunofluorescence, confocal microscopy and in situ hybridization at different times after surgery. The study showed that perichondrium transplants differentiated into a cartilage structure that filled out the defects with chondrocytes expressing elevated levels of Col2a1 and producing a matrix rich in proteoglycans. Study V is a case series of four patients with a mean age of 40 (range 37-47) years with osteoarthritis in the distal radioulnar joint. Our retrospective clinical follow-up is presented and discussed in relation to more traditional techniques. Pain, range of motion, strength, and patient-rated outcome measures improved and were stable at the mid-term follow-up 7.5 years after surgery.

In conclusion, perichondrium seems to be a suitable tissue for joint reconstruction and tissue engineering.