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- Berglund, Maria, 1975-
(författare)
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Biomolecular Aspects of Flexor Tendon Healing
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Flexor tendon injuries in zone II of the hand (i.e. between the distal volar crease and the distal interphalangeal joint) can be costly for both the afflicted individual and society because of the high cost of a long rehabilitation period, complicated by tendon ruptures or scarring with adhesion formation, causing impaired range of motion. The aim of the present thesis was to characterize more fully the deep flexor tendon, the tendon sheath and their response to injury in a rabbit model in order to find potential targets to improve the outcome of repair. The intrasynovial rabbit deep flexor tendon differed from the extrasynovial peroneus tendon in the expression of collagens and transforming growth factor-β1 gene expression. Differences were also found in collagen III and proteoglycans between regions of the flexor tendon subjected to either compressive or tensile load. After laceration and subsequent repair of the flexor tendon, a shift in collagen gene expression from type I to type III occurred. Proteoglycans were generally increased with the notable exception of decorin, a potential inhibitor of the profibrotic transforming growth factor-β1 which was markedly increased during the first two weeks after repair in tendon tissue but remained unaltered in the sheaths. Both vascular endothelial growth factor and basic fibroblast growth factor mRNA levels remained essentially unaltered, whereas insulin-like growth factor-1 increased later in the healing process, suggesting potential beneficial effects of exogenous addition, increasing tendon strength through stimulating tenocyte proliferation and collagen synthesis. Matrix metalloproteinase-13 mRNA levels increased and remained high in both tendon and sheath, whereas there was only a transient increase of matrix metalloproteinase-3 mRNA in tendon. We could also demonstrate a significant increase of the proportion of myofibroblasts, mast cells and neuropeptide containing nerve fibers in the healing tendon tissue, all components of the profibrotic myofibroblast-mast cell-neuropeptide pathway.
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| 2. |
- Bjerkefors, Anna
(författare)
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Performance and trainability in paraplegics : motor function, shoulder muscle strength and sitting balance before and after kayak ergometer training
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Spinal cord injury (SCI) results in a complete or partial loss of motor and/or sensory function below the injury level. An SCI causes extensive functional impairment compelling many persons to wheelchair usage. Maintaining an adequate strength and control of trunk and shoulder muscles becomes essential, as the majority of every day tasks will be performed in a sitting position. Moreover, physical exercise is crucial to avoid risks connected with a sedentary life-style. Therefore, it becomes important to find suitable, effective, and attractive physical activities to retain and even improve motor functions achieved during rehabilitation. Ideally, such a training activity should be versatile and have the potential to improve several capacities beneficial to everyday life and thereby increase the independence of persons with SCI. Kayak paddling appears to fulfil several of the criteria for such an activity. Objectives: The overall aims were to see if, and to what extent, a period of training on a modified kayak ergometer could influence functional performance as well as specific qualities, such as, shoulder muscle strength and sitting balance control in a group of postrehabilitated persons with thoracic SCI. An additional aim was to understand more about the availability of the trunk muscles in a person with a clinically complete thoracic SCI and how the trunk muscles are used to maintain upright sitting in response to balance perturbations. Methods: Ten adult post-rehabilitated persons with thoracic SCI performed 30 sessions of kayak ergometer training for a 10-week period, with progressively increased intensity and balance demand in the medio-lateral direction. Pre- and post-training measurements included performance in functional wheelchair tests, maximal voluntary shoulder muscle strength, and trunk stability in response to support-surface translations. Electromyographic (EMG) recordings from deep and superficial trunk muscles were obtained in a sub-sample of two subjects, one with a high thoracic SCI and one able-bodied person. Results: There were significant improvements with training in functional performance, shoulder muscle strength, and the ability to maintain an upright sitting posture in response to balance perturbations in the group of persons with SCI. The EMG results revealed that the person with a high thoracic SCI, clinically classified as complete, was still able to activate trunk muscles below the injury, both in maximal voluntary efforts and in response to balance perturbations, but the response pattern differed from that of the ablebodied. Conclusions: The improvements in test-performance observed with the kayak ergometer training in the persons with SCI should enhance their capacity to master similar challenges in everyday life, which, in turn, might lead to a greater independence. The pilot data on muscle activation highlight the importance of including examination of trunk muscle function in persons with thoracic SCI in relation to injury classification, prognosis, and training prescription.
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| 3. |
- Fischer, Per, 1981-
(författare)
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Hemi and total wrist arthroplasty
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Aim: To study implant survival and implant loosening following primary total wrist arthroplasty (TWA) using four different implants. To report outcome following wrist revision arthroplasty. To evaluate a new radial wrist hemi arthroplasty (RWHA) design clinically and biomechanically.Method: The studies included 136 primary TWAs and 16 revision TWAs, both studies with prospectively collected data. Six fresh frozen cadaveric wrist specimen were used for biomechanical analysis. The RHWA was evaluated clinically in a pilot series of 20 cases.Results: Total implant survival was 92% but with high frequency of implant loosening of surviving Re-Motion implants. None of the surviving Maestro implants were considered radiographically loose. Implant survival following revision arthroplasty was 75%, considerably lower than following primary TWAs. However, none of the patients with surviving revision implants had pain at rest and little or no pain in activity. The surgical procedure and placement of the RHWA was feasible. Overall, the kinematic and functional changes appeared acceptable compared to the native wrist. None of the patients underwent revision following RHWA but reoperation was performed in 7 patients on the indication of persistent pain. However, patients reported relief of pain and improvement of patient-reported outcome measures.Conclusion: High long-term implant survival and no signs of radiographic loosening was found for the Maestro implant. However, the Maestro implant is no longer available on the market and we believe there is a need for new TWA designs. Revision arthroplasty is a valid option in the management of failed TWA. However, implant survival is lower than for primary TWAs and as many as 25% require additional surgery. Promising results were found using the new RHWA design but the implant needs modification before further testing.
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