The Knee
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A retrospective study of a consecutive cohort of 109 patients, under the age of 60, who had either a Patellofemoral replacement (PFR), Unicompartmental replacement (UKR) or a Total knee replacement (TKR). They were operated on by two senior surgeons between 2002 and 2006 at the Avon Orthopaedic Centre in Bristol. The aim of this study was to look at the effect of knee replacement on the employment status of this group of patients. ⋯ This is the first study to compare employment status following Patellofemoral, Unicompartmental knee and Total Knee Replacement. TKR and UKR are effective in returning patients under 60 years old to active employment and this is typically 3 months following surgery. Patients who had a PFR did not experience the same benefits in terms of numbers returning to work, time to do so and their subjective opinion as to their ability to cope with normal duties.
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Periprosthetic tibial plateau fractures (TPF) are rare but represent a serious complication of unicompartmental knee arthroplasty (UKA). As TPFs usually occur perioperatively, these can be associated with extended sagittal saw cuts during surgery. The aim of the study was to evaluate TPF as a function of extended sagittal saw cuts. ⋯ Extended sagittal saw cuts in UKA weaken the tibial bone structure. Our results show that descendent extended sagittal saw cuts of 10 degrees reduce fracture loads by about 30%. Surgeons should be aware of the potential pitfalls of an extended sagittal saw cut, as this can lead to reduced loading capacity of the tibial plateau and increase the risk of periprosthetic TPF.
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The viability of unicondylar knee arthroplasty (UKA) as a stand-alone or temporising option for the management of gonarthrosis is a topic of considerable contention. Despite recent advances in prosthesis design and surgical technique, as well as mounting evidence of long-term survivorship, UKA remains infrequently used, accounting for just 8-15% of all knee arthroplasties. Instead this group is more typically managed using total knee arthroplasty (TKA). ⋯ We show in a series of 200 knees that candidacy for UKA is widespread; representing 47.6% of knees. Furthermore, we also show for the first time, that not only is UKA functionally superior to TKA (based on Total Knee Questionnaire (TKQ) scores), but scores in medial and lateral UKA knees do not differ significantly from normal, non-operative age- and sex-matched knees (t=1.14 [38], p=0.163; and t=1.16 [38], p=0.255 respectively). Finally, we report that UKA offers a substantial cost saving over TKA ( pound 1761 per knee) indicating that UKA should be considered the primary treatment option for unicompartmental knee arthritis.
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As implants are made in incremental sizes and usually do not fit perfectly, surgeons have to decide if it is preferable to over or undersize the components. This is particularly important for unicompartmental knee replacement (UKR) tibial components, as overhang may cause irritation of soft tissues and pain, whereas underhang may cause loosening. One hundred and sixty Oxford UKRs were categorised according to whether they had minor (<3 mm, 70%) or major (>or=3 mm, 9%) tibial overhang, or tibial underhang (21%). ⋯ There was no difference between the 'minor overhang' and the 'underhang' group. We conclude that surgeons must avoid tibial component overhang of 3 mm or more, as this severely compromises the outcome. Although this study showed no difference between minor overhang or underhang, we would advise against significant underhang because of the theoretical risk of component subsidence and loosening.
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We present the first case of late spontaneous dislocation of a high flexion polyethylene insert after Genesis II total knee arthroplasty. Dislocation of the fixed insert occurred at 14 months post surgery while walking down a steep aircraft staircase. ⋯ The clinical presentation, possible causes and management are discussed. A surgical error, failure to remove a posterior femoral osteophyte, seems the most probable cause for the late insert dislocation in our case.