Total Knee Arthroplasty After Failed Unicompartmental Knee Arthroplasty. Clinical Results, Radiologic Findings, and Technical Tips.

BACKGROUND: The loss of anatomic references and bone stock turns unicompartmental knee arthroplasty (UKA) revision surgery difficult, and according to some authors, it is technically as challenging as a total knee arthroplasty (TKA) revision surgery. METHODS: A retrospective review of 559 Oxford medial UKA was performed between 2007 and 2013. Nineteen knees were revised to TKA for reasons other than infection, most commonly for osteoarthritis progression. RESULTS: The most frequent cause of failure in our series was osteoarthritis progression (10 cases, 52.63%). In 15 patients (78.95%), tibial stems were needed, and in 10 (55.5%), metallic blocks for augmentation of tibial plateau were used. Postoperative radiographic studies showed a correct implant alignment, preserving adequate joint line (24.8 mm), and patellar (1.1 mm) height (according to Insall-Salvati). After a mean follow-up of 21 months (range 6-51) mean values of 78.8 (standard deviation [SD] = 16.8) and 62.3 (SD = 19.6) were obtained for the physical and mental scores of the Knee Society Score test. In the SF-36 tests mean values of 45.2 (SD = 7.6) and 53 (SD = 5.2) were obtained for the physical and mental scores respectively. In one case, a varus/valgus instability occurred intraoperatively and it required revision with a prosthesis with higher constriction. No thromboembolic or infectious events were observed during postoperative follow-up. CONCLUSION: Following a standardized technique, UKA revision surgery can be achieved with TKA in almost every case despite bone stock loss and lack of anatomic landmarks.

Prótesis unicompartimental lateral de rodilla. Indicaciones, técnica y resultados a mediocorto plazo / Lateral unicompartimental knee replacement: indications, sugery procedures and shortmidterm outcomes

Objetivos: En los casos de gonartrosis del compartimento lateral, la prótesis unicompartimental es una de las alternativas quirúrgicas utilizadas, por el menor traumatismo que supone, corta estancia hospitalaria y rápida recuperación del paciente. Este estudio revisa nuestros casos. Material y método: Se describe la técnica utilizada y la prótesis implantada (polietileno móvil bicóncavo, OXFORD DOMED). Estudio observacional longitudinal retrospectivo de 15 casos intervenidos entre 2010 y 2013, 13 mujeres y 2 hombres, con una media de edad de 60’7 años, con diagnóstico de gonartrosis monocompartimental externa, sin afectación del compartimento medial ni fémororrotuliano y con ligamentos cruzados indemnes, con un seguimiento medio de 25 meses. Se les ha pasado escalas de funcionalidad y satisfacción. Resultados: Los resultados son favorables, con una mejoría de 6,60 puntos en la escala de EVA, de 3,73 sobre 1 en la función postoperatoria, muy satisfactorios en la OKS con una media de 38 puntos sobre 50, sin necesidad de ninguna revisión quirúrgica. Observamos tendinitis anserina en un 20% de los casos. Conclusiones: Se valoran los beneficios de esta cirugía frente a sus alternativas, así como de sus posibles inconvenientes. La artroplastia de rodilla unicompartimental externa es una alternativa efi caz en casos de gonartrosis confi nada al compartimento lateral sin otras lesiones asociadas

Objectives: In patients with lateral osteoarthritis of the knee, use of external unicompartmental knee arthroplasty it is a well known surgical alternative, used by the minor trauma involved, short hospital stay and rapid recovery. The purpose of this study is to show the clinical outcomes to short-medium term of patients undergoing this procedure. Methods: we describe the technique used and the peculiarities of the prosthesis (A Mobile-bearing lateral unicompartmental knee replacement, Oxford Domed(R)). This is an observational retrospective longitudinal study, of 15 arthroplasties performed in 13 women and 2 men, between 2010 and 2013, with a mean age of 60’7 years, with a diagnosis of lateral osteoarthritis of the knee, without involvement of the medial or patellofemoral compartment and cruciate ligaments functionally intact, with a mean follow up of 25 months. All patients complete the Oxford Knee Score and Visual Analog Scale (VAS) during the study. Results: The results are favorable, with an improvement of 6.60 points on the EVA, 3.73 for 1 in the postoperatory funcionality, the OKS very satisfactory with an average of 38 points over 50 and without any postoperative function surgical revision. Anserine tendinitis was observed in 20% of cases. Conclusions: The benefi ts of this surgery against their alternatives are assessed, and their potential drawbacks. External unicompartmental knee arthroplasty is an effective alternative in cases of knee osteoarthritis of the lateral compartment with no other associated injuries (AU)