Assessing and improving clinical outcomes of the cementless Oxford unicompartmental knee replacement tibial component

Cementless Oxford Unicompartmental Knee Replacements (OUKR) are known to have a lower revision rate than cemented, but have a higher incidence of early tibial fracture, and is not known how their symptoms compare. The aims of this thesis were firstly to compare the symptoms following cemented and cementless OUKR and explore factors that may influence them, and secondly to assess design changes which may reduce their risk of fracture. A study comparing Cemented and Cementless OUKR demonstrated that most pain reported by patients is intermittent, and that 42% more patients with Cementless OUKR report having no pain compared to Cemented OUKR. Radiolucencies at the tibial wall, and bone density around the tibial keel, are characterised for the first time in literature. Radiolucencies around the tibial component were found only where there was no porous coat, and these radiolucencies were associated with an increased likelihood of patients reporting pain. This suggests that the porous coating should be applied to all bone-implant interfaces. Bone density around the keel changes in the years following surgery, but this change is unrelated to pain. Despite the benefits of Cementless OUKR, cemented tibial components are still used, in part due to concerns about periprosthetic tibial fractures in Cementless OUKR. These occur most commonly around very small components. The keel has the same depth for all sizes, suggesting that the relatively larger keels are an important risk factor for the smaller tibias. To address this, changes to keel design were studied using a plastic bone test in which the push-in force was considered to be related to the fracture risk and the pull-out force was considered to be related to primary fixation. From these tests, two new keel designs were proposed: a small porous keel without a window, and a small porous-walled smooth-edged keel. A more radical redesign replacing keels with two anterior angled pegs was also proposed to address fundamental limitations of a keel. More physiologically relevant tests were developed using plastic bone blocks machined to the shape of a very small tibia that experienced a fracture. These tests used load-to-fracture to assess fracture risk and anterior lift-off with posterior loading to assess primary fixation. Important assumptions about the effect of keel size and interference are assessed with these tests. The small porous keel, compared to the standard keel, reduced fracture load, and had similar fixation. The smooth-edged keel similarly reduced the fracture load but had better fixation. The two-peg component greatly reduces fracture risk and virtually eliminates pathological implant micromotion. The thesis concludes with proposed next steps leading to clinical use of these new designs. The small porous and porous-walled smooth-edged keels require minor modifications to manufacturing, while the two-peg device requires modifications to manufacturing, surgical technique, and instrumentation. The new small keels could be introduced relatively rapidly after short clinical studies, whereas the two-peg device would require more in-depth safety assessments. Whichever design is introduced, all surfaces interfacing with bone in the tibial component should have a porous coating

Spontaneous Osteonecrosis of the Knee: Systematic review & Delphi Study

Background: Numerous treatments for Spontaneous Osteonecrosis of the Knee (SONK) have been described, but there is little guidance regarding which joint-preserving treatments to use for different disease stages. Aims: To assess the effectiveness and appropriateness of non-operative and operative joint-preserving treatments for SONK as a whole, as well as for different disease stages. Methodology: A systematic review with narrative synthesis of four bibliographic databases was undertaken to identify studies evaluating the effectiveness (clinical, radiological outcomes and failure rates) of joint-preserving treatment for SONK. The findings of the review were then used to inform a 2-round Delphi study involving an international expert panel to establish consensus on preferred first and second-line treatments for different disease stages. Results: Twenty eligible studies were identified: 8 described non-operative measures and 14 surgical interventions (2 studies described several treatments). One study was a randomised controlled trial evaluating foot orthoses, which proved more effective than usual treatment with analgesia and physiotherapy. Supportive treatment with analgesia and restricted weight bearing, bisphosphonates and most other joint-preserving surgical interventions had promising results from small case series. Nineteen experts contributed to the first round of the Delphi study and 14 to the second round. Consensus was achieved for 3 months of rest and analgesia as first-line treatment in early and intermediate-stage disease, without consensus on the most appropriate second-line treatment. For late-stage disease, consensus was not reached for first-line treatment although 50% agreed against joint-preserving therap. For second-line treatment, 78.6% would use arthroplasty. Conclusions: Rest and analgesia with or without restricted weight-bearing appears to be an appropriate, and often effective first-line treatment for early or intermediate-stage disease. Arthroplasty, rather than joint-preserving therapy is the most commonly utilised treatment for late-stage disease. However, existing research is limited, and higher-level evidence is required before being able to definitively state which joint-preserving treatments are most effective for SONK of different stages

Epidemiology of injuries in high-level youth sport in Luxembourg [Abstract]

peer reviewe

Maioregen osteochondral substitute for the treatment of knee defects: A systematic review of the literature

Background: This study aims to investigate the clinical and radiological efficacy of three-dimensional acellular scaffolds (MaioRegen) in restoring osteochondral knee defects. Methods: MEDLINE, Scopus, CINAHL, Embase, and Cochrane Databases were searched for articles in which patients were treated with MaioRegen for osteochondral knee defects. Results: A total of 471 patients were included in the study (mean age 34.07 ± 5.28 years). The treatment involved 500 lesions divided as follows: 202 (40.4%) medial femoral condyles, 107 (21.4%) lateral femoral condyles, 28 (5.6%) tibial plateaus, 46 (9.2%) trochleas, 74 (14.8%) patellas, and 43 (8.6%) unspecified femoral condyles. Mean lesion size was 3.6 ± 0.85 cm2. Only four studies reported a follow-up longer than 24 months. Significant clinical improvement has been reported in almost all studies with further improvement up to 5 years after surgery. A total of 59 complications were reported of which 52 (11.1%) experienced minor complications and 7 (1.48%) major complications. A total of 16 (3.39%) failures were reported. Conclusion: This systematic review describes the current available evidence for the treatment of osteochondral knee defects with MaioRegen Osteochondral substitute reporting promising satisfactory and reliable results at mid-term follow-up. A low rate of complications and failure was reported, confirming the safety of this scaffold. Considering the low level of evidence of the study included in the review, this data does not support the superiority of the Maioregen in terms of clinical improvement at follow-up compared to conservative treatment or other cartilage techniques

Osteoarthritis

Osteoarthritis is one of the most debilitating diseases affecting millions of people worldwide. However, there is no FDA approved disease modifying drug specifically for OA. Surgery remains an effective last resort to restore the function of the joints. As the aging populations increase worldwide, the number of OA patients increases dramatically in recent years and is expected to increase in many years to come. This is a book that summarizes recent advance in OA diagnosis, treatment, and surgery. It includes wide ranging topics from the cutting edge gene therapy to alternative medicine. Such multifaceted approaches are necessary to develop novel and effective therapy to cure OA in the future. In this book, different surgical methods are described to restore the function of the joints. In addition, various treatment options are presented, mainly to reduce the pain and enhance the life quality of the OA patients