RESUMEN
Posterior cruciate ligament (PCL) release may be required to balance the flexion gap in PCL retaining TKA. This study examines the incidence and functional consequences of PCL release in both fixed and mobile bearing TKA. A consecutive series of 1388 TKAs with 1014 fixed bearing, and 374 mobile bearing implants were reviewed for prevalence of partial PCL release, restoration of potential flexion and objective knee stability at minimum one-year follow-up. Patients receiving mobile bearing inserts were more likely to need partial PCL release (42% versus 17.5%). The occurrence of partial PCL release did not have a significant impact on knee range of motion and subjective knee stability. The need for a partial PCL release appears to be greater in mobile than in fixed bearing. Knees that required a release in both groups demonstrated no difference in restoration of flexion compared with unreleased knees and no adverse effects on flexion stability.
Asunto(s)
Artroplastia de Reemplazo de Rodilla/métodos , Ligamento Cruzado Posterior/cirugía , Anciano , Artroplastia de Reemplazo de Rodilla/estadística & datos numéricos , Estudios Transversales , Humanos , Articulación de la Rodilla/fisiología , Articulación de la Rodilla/cirugía , Persona de Mediana Edad , Rango del Movimiento ArticularRESUMEN
BACKGROUND: Determining the cause of synovitis following total knee arthroplasty (TKA) can be challenging. The differential diagnoses include infection, hemarthrosis, instability, crystalline disease, wear debris or idiopathic causes. Wear particle synovitis can mimic periprosthetic infection with symptoms of pain and effusion. Radiographs and physical exam are often inconclusive in differentiating the two. Synovial fluid analysis is routinely used in evaluating periprosthetic infections. We examined the association between synovial white blood cell count and differentials, and polyethylene wear and osteolysis, to see if fluid analysis can aid in establishing the diagnosis of wear particle synovitis. METHODS: A cell count and differential was obtained from synovial fluid samples from 54 TKAs undergoing revision for aseptic failure. Explanted polyethylene inserts were analyzed for linear and volumetric wear, oxidation (ketone peak height), and damage features. Analysis was performed to assess the relationship between cell counts and polyethylene wear indicators as well as severity of intra-operative and radiographic osteolysis. RESULTS: Total and percent mononuclear (monocyte and lymphocyte) cell counts were found to be elevated in the presence of documented wear debris synovitis and an association was suggested between their levels and maximum ketone levels. CONCLUSION: The present study implies that the differential cell count of knee fluid can help distinguish wear debris from infection as a source of synovitis following TKA and identifies the value of the mononuclear cell count as a possible tool to assess abnormal wear rates of the polyethylene insert. Further research into identifying the exact role of monocytes in the wear debris synovitis and osteolytic pathways is warranted. LEVEL OF EVIDENCE: Level II, diagnostic study.
Asunto(s)
Artroplastia de Reemplazo de Rodilla/efectos adversos , Polietileno/efectos adversos , Líquido Sinovial/citología , Sinovitis/patología , Anciano , Anciano de 80 o más Años , Diagnóstico Diferencial , Femenino , Humanos , Recuento de Leucocitos , Masculino , Persona de Mediana Edad , Sinovitis/etiologíaRESUMEN
The frequency of unicompartmental knee arthroplasty (UKA) procedures has increased rapidly over the past decade. Some conflicting evidence exists concerning UKA revision. Some studies have found UKA revisions to be comparable with primary total knee arthroplasty, whereas others have found that UKA revisions require a higher need for tibial stems and augments and have more complications and worse results. This study seeks to determine the effect of a conservative tibial resection in UKA on the ease of revision and its outcomes in a consecutive patient cohort.Thirty-five patients underwent 37 conversions of a medial UKA to a total knee arthroplasty. Clinical, functional, and radiological data were evaluated. At revision, a primary total knee arthroplasty implant was used in 24 (88.8%) patients who underwent a conservative tibial resection during their UKA compared with only 3 (30%) patients who underwent an aggressive tibial resection (P<.001). The odds ratio of needing an augment or stem was 26.8 (95% confidence interval, 3.71-194) when an aggressive resection was performed compared with a conservative resection during the UKA.The results indicate that revision of a medial UKA can be comparable with a primary TKA when a conservative tibial resection is performed at the time of the primary UKA. It is possible to preoperatively predict which patients might need the use of augmentation and stems during UKA revision. This data should guide surgeons to strive for the most conservative UKA tibial resection possible in patients undergoing medial UKA.