Thesis--Lund University, 1995.

Background: Highly porous Trabecular Metal™ acetabular components are increasingly being used in revision hip arthroplasty as they facilitate ingrowth, provide a useful mechanism to deal with bone loss and may decrease the risk of infection. The purpose of this audit was to describe: 1) the short-term radiological outcomes of revision hip arthroplasty with Trabecular Metal™ components and augments. 2) the total number of hip arthroplasty surgeries over five years, and indications for revision. Methods: A retrospective folder and radiograph review of all patients who had revision total hip arthroplasty (THA) at a tertiary level hospital from February 2012 to February 2017 was done. Results: There were 979 THAs performed over the period – 863 (87%) primary THAs, and 116 (12%) hip revision cases performed in 107 patients. Of the 116 (107 patients) hip revisions, there were seven (6%) re-revisions in five patients. Trabecular Metal™ was used for revision in 16 hips (14 patients), which is 13.7% of the total 116 revisions. There were ten females and four males with an average age of 61 years. The average duration of follow-up in this group was 18.5 months (1.5– 39.2). In these 16 Trabecular Metal™ hips, there were three (18.7%) early failures of fixation due to technical errors. The indications for revision were aseptic loosening 67 (58.6%), septic loosening 11 (9.5%), liner wear 18 (15.5%), periprosthetic fracture five (4.3%), other 15 (13%). Conclusion: In our institution, Trabecular Metal™ revisions had a 18.7% early failure rate due to technical error. 12% of the arthroplasty is revision surgery. The indications for revision are similar to published literature.

No description available.

End-stage osteoarthritis is characterised by pain and reduced physical function, for which total knee arthroplasty (TKA) is recognised to be a highly effective procedure. Post-operative outcome and resultant function however is variable. Many factors are thought to influence outcome; in particular quadriceps muscle strength is one of the strongest predictors of the patient’s ability to perform functional tasks. Muscle atrophy has been shown to account for only a third of the variance in muscle power, the remainder is currently unexplained. In this thesis it is hypothesised that physiological and mechanical factors will affect muscle power post TKA. A new design of prosthesis with an axis of rotation of the knee based on new kinematical observations has been suggested to confer a mechanical advantage to the knee extensor mechanism by lengthening its moment arm, and thus reducing the muscular effort required to extend the knee, however this has not as yet been clinically demonstrated. A strong extensor mechanism is recognised as being paramount to the patients return to functional activity following TKA, but there has been no consideration as to the mechanisms how and to what extent the muscle tissue actually recovers. It is known that muscle satellite cells are essential for the regeneration of skeletal muscle and that these cells are activated following damage, but these have not been considered in relation to recovery from orthopaedic procedures. It is hypothesised that the number of satellite cells in the extensor mechanism will vary in the patient population and will influence muscle recovery. A double blind randomised controlled trial of 212 TKA patients was conducted to compare the new implant design with a traditional model. Patient outcome was assessed at four points over a one year period. The new implant was superior in measures of knee flexion, lower limb power output and by patient report questionnaire (Oxford Knee Score) Two-way ANOVA, p = <0.001 in all cases. Extensor mechanism power was significantly increased between all four assessment points in the new implant group, the control group demonstrating change between the second and third assessment only (p= <0.001). Analysis of the outcome assessments used demonstrated a changing relationship between function and patient report of that function. Regression models demonstrated that patient report of function became more consistent with direct functional assessment as the influence of pain diminished post-operatively. A hierarchical model is presented that highlights the limitation of patient report data in isolation. Muscle satellite cells were isolated from biopsies of the quadriceps muscle of 18 patients at the time of surgery and counted by an immunofluorescent staining technique. The number of satellite cells detected accounted for a third of the postoperative variance in power output (R2 = 36.6%). This was confirmed in another cohort of 11 patients with a more sensitive qPCR technique. It was further found that the activated satellite cells accounted for around two thirds of the change in postoperative power output (R2 = 66.7%). In conclusion, both mechanical and physiological factors have a significant effect on muscle power post total knee arthroplasty.

Mosaic Arthroplasty is a well-accepted surgical approach to treating focal cartilage defects of the knee. However, the task of creating the mosaic of osteochondral grafts that optimally restores the cartilage surface is technically demanding. Conventional techniques require the surgeon to reconstruct a complex, three-dimensional surface by eye and experience only. There is evidence that this type of procedure is sensitive to technique: grafts that are transplanted proud of the native cartilage surface tend to show evidence of cartilage fissuring and fibrillation prematurely. Two computer-assisted techniques (navigation by optical tracking and guidance by patient-specific templates) were investigated to determine whether they would have a beneficial effect on surgical execution, and whether any differences in execution had any correlation to surgical outcome. The experimental work can be broken into two parts: an in vitro study that compared the accuracy of execution of an optically navigated group versus a template guided group, and an in vivo animal trial that compared both computer assisted techniques to the conventional, non-assisted approach. The results of the pilot study indicated that, while there were higher errors in the individual measures of position, orientation, and plug depth in the optically navigated group, there was no significant difference in the overall fidelity of the geometric surface produced between the two groups. The results of the animal trial indicated that both computer assisted techniques produced morphological results that were superior to the conventional technique. The two computer-assisted techniques also showed a significantly better treatment effect as seen by their higher histological scoring. Furthermore, a significant linear correlation was found between morphological results and histological score. Overall, the experiments demonstrated that surgeons and patients could potentially benefit from the use of computer-assisted techniques in the short term. Further work is required to prove long-term beneficial effect. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2012-11-02 20:50:33.957

Introduction There is little known about the acute status of TKA patients, as many studies have focused on the long-term outcomes (Aarons et al., 1996). Knowing the acute status can aid physiotherapists in planning postoperative treatment protocols and help with discharge planning. This research examines the postoperative status of total knee arthroplasty (TKA) patients on discharge from an acute setting. The objectives of the study were to establish pain, ROM of the operated knee, functional level, socio-demographic factors, clinical data and the relationship between identified factors and postoperative functional status of TKA patients in the acute setting. Materials and Methods This study is classified as a quantitative, cross-sectional design. Sociodemographic and clinical data, pain, range of movement (ROM) and function of TKA patients were collected on day three post operation. A selfdesigned data capture sheet, the goniometer, VAS (Visual Analogue Scale) and ILOA (Iowa Level of Assistance) were used to measure data. Results Forty-four patients were assessed. There were 41% males and 59% females. The average age was 67 years and BMI was 30kg/m2. All patients had decreased ROM and 82% had poor quadriceps strength. Pain on walking was 5.8 on the VAS and correlated with the ILOA score. Pain on rest was 3.3 and when climbing stairs was 2.4. Sixty-one percent of subjects performed supine to sit, 59% performed sit to stand and 43% performed ambulation independently. Men performed better with an ILOA score of 24. Females had an ILOA score of 31. Length of stay (LOS) was 5.7 days. Females, older subjects and those with no medical conditions were more likely to stay in hospital for longer. Conclusion Knowledge of these factors will help to give patients a likely prognosis following a TKA and target future rehabilitation. Patients should receive adequate pain control to improve their functional ability. More attention should be given to female patients as they perform worse than men. Patients in this population should be referred for outpatient physiotherapy post-discharge, as their status on day three post operation reflected poor ROM, quadriceps muscle strength and function which may affect their rehabilitation outcome.

No description available.

One major barrier that prevents cartilage integration following mosaic arthroplasty is the presence of a zone of chondrocyte death (ZCD) that is generated upon osteochondral graft harvest, which can extend up to 400 μm into the cartilaginous portion of the graft. In order for cartilage integration to occur, chondrocytes must be present at the graft periphery; however chondrocyte migration through the ZCD to the graft periphery is inhibited by the dense extracellular matrix (ECM) of cartilage. The purpose of this study was to develop a method for increasing the number of chondrocytes within the ZCD and at the periphery of a cartilage graft. This method used a combination of collagenase treatment (as a means of degrading the ECM within the ZCD) and chondrocyte chemotaxis (as a means of improving chondrocyte migration into the ZCD and to the cartilage periphery). Results indicate that treating bovine articular cartilage with 0.6 % collagenase for 10 min decreased with extent of the ZCD by approximately 35% (collagenase: 109 ± 13 μm; control: 175 ± 13 μm). Each of the chemotactic agents tested (PDGF-bb, bFGF, and IGF-I) were found to induce bovine chondrocyte chemotaxis at concentrations of 25 ng/mL in modified Boyden chamber experiments. However, in bovine articular cartilage samples that were pre-treated with collagenase (0.6% for 10 min), supplementation with 25 ng/mL of either PDGF-bb or bFGF had no apparent effect on the ZCD relative to samples treated only with collagenase (PDGF-bb: 85 ± 10 μm; bFGF: 88 ± 10 μm). Alternatively, bovine articular cartilage samples pre-treated with collagenase (0.6% for 10 min) and supplementation with 25 ng/mL IGF-I resulted in an approximately 65% reduction in the ZCD relative to samples treated only with collagenase (IGF-1: 38 ± 5 μm). Thus, treating osteochondral grafts with collagenase and IGF-1 induces chondrocyte repopulation of the zone of chondrocyte death generated by osteochondral graft harvesting, and could enhance cartilage integration after implantation. / Thesis (Master, Chemical Engineering) -- Queen's University, 2009-12-21 20:16:05.815

As the number of total knee arthroplasty (TKA) procedures increases annually, the patient demographic is shifting to include younger patients with higher expectations for post-operative function. The aim of this study was to compare movement patterns during activities of daily living among TKA patients and a healthy, age-matched group using 3D motion analysis. Specifically, this analysis looked at walking on level and inclined surfaces, as well as sitting up and down from a chair. It was predicted that (1) TKA patients would exhibit reduced knee extension moments at the operated limb and increased adduction moments at the contralateral limb during gait, (2) walking downhill would result in greater differences between TKA and control groups, compared to level walking, and (3) TKA participants would have greater flexion angles, moments and power values at the hip, compared to controls, during the sit-stand tasks. Seventeen participants (age=62±6 years, BMI=30±3 kg/m2, time after surgery=11±5 months) were recruited from the Ottawa Hospital, having undergone unilateral TKA by the same surgeon. An age-matched control group was composed of 17 individuals (age=63±8 years, BMI=27±4 kg/m2) who were recruited from the local community. Three dimensional (3D) biomechanical assessment was conducted with all participants performing five trials of walking on level and inclined surfaces, stair ascent and descent as well as sit-stand tasks. Results from this study were focused on gait and sit-stand transitions, showing that TKA participants exhibited altered gait patterns on both walking surfaces, with significantly smaller knee flexion angles and moments, as well as reduced peak power at the knee. The TKA group also experienced reduced knee extension moments; however, this was only significant for downhill walking. Consistent with our hypothesis, downhill walking resulted in greater discrepancies between the groups compared to level walking. Contrary to our third hypothesis, TKA participants exhibited significantly smaller peak hip flexion angles and moments during the sit-stand task, along with reduced hip abduction angles and knee abduction moments. The reduced knee flexion kinematics and kinetics observed during gait tasks, combined with the differences in frontal plane mechanics observed during the sit-stand task suggest that altered loading patterns persist six to twelve months after surgery. This may be a result of continued pre-operative movement patterns as well as the surgery itself, and should be kept in mind when developing rehabilitation programs for this patient population.

Thesis (MHSc--Health Science) -- Auckland University of Technology, 2003. / Appendices not included in e-thesis. Also held in print (121 leaves, 30cm.) in Akoranga Theses Collection. (T 617.582 MAR)