RESUMEN

BACKGROUND: Accumulating evidence has suggested that sleep disturbances and disorders are common in patients who undergo knee arthroplasty. Revision surgery represents one of the most catastrophic outcomes of knee arthroplasty. However, it remains unclear whether sleep traits are the causes or consequences of knee arthroplasty revision. This study aimed to genetically examine the relationships between sleep traits and knee arthroplasty revision. METHODS: To determine the causal relationship between sleep traits and knee arthroplasty revision, we employed two-sample Mendelian randomization (MR) using summary statistics from the largest publicly available genome-wide association studies (GWASs). The MR design uses genetic variants as instrumental variables to help separate causal relationships from non-causal associations. The main analyses included an inverse variance weighted (IVW) meta-analysis to obtain primary effect estimates. Sensitivity analyses involving the weighted median approach and MR-Egger regression were also conducted to check for potential pleiotropic biases. Numerous complementary sensitivity analyses were also performed to identify statistically significant causal correlations when there were horizontal pleiotropy and heterogeneity across variants. Finally, a reverse MR analysis was performed to evaluate the possibility of reverse causation. RESULTS: In the absence of heterogeneity and horizontal pleiotropy, the IVW method revealed that genetically-predicted short sleep duration short sleep duration (average sleep duration of 24 h is 6 h or less) was positively correlated with the risk of knee arthroplasty revision (odds ratio = 1.03, 95% confidence interval = 1.01-1.05, and P = 0.003), while the association between genetically-predicted long sleep duration and knee arthroplasty was negative. The reverse MR analysis did not yield evidence supporting reverse causality relation between knee arthroplasty revision and sleep phenotypes. CONCLUSION: This research indicated that, of the 10 sleep phenotypes we analyzed, only sleep duration was causally associated with knee arthroplasty revision. These discoveries added to the understanding of the role of sleep traits in the etiology of knee arthroplasty revision, which might further expand our insights into the prevention of knee arthroplasty revision.

Asunto(s)

RESUMEN

BACKGROUND: International rates of patellar resurfacing in primary total knee arthroplasty (TKA) are highly variable. This study sought to determine how trends in patellar resurfacing rates have changed between 2004 and 2022. In addition, we investigated how modern rates of revision have varied between resurfaced and un-resurfaced patellae in primary TKA among national joint registries. METHODS: Data between 2004 and 2022 was obtained either from the publicly available joint registry annual reports, a literature review, or via direct correspondence with registry personnel in Sweden, New Zealand, Australia, the United States, Norway, the United Kingdom, the Netherlands, Switzerland, Canada, and India. Only English-language national joint registries or data via direct correspondence with registry administrators were utilized. Additionally, the 10-year cumulative risk of revision TKA with and without patellar resurfacing was pulled from those registries that had this data available. RESULTS: There were persistent differences in the rates of patellar resurfacing among countries. Australia documented a 40% increase in patellar resurfacing rates, while other countries demonstrated modest or little change in resurfacing rates. This may indicate that surgeons are making the decision to resurface based on national TKA revision rates. The average rates of patellar resurfacing in primary TKA ranged from 4% in Sweden to 94% in the United States. Canada, the United States, Australia, and Switzerland documented a lower risk of revision when the patella was resurfaced, while Sweden, conversely, showed a higher risk of revision with resurfacing. CONCLUSIONS: Rates of patellar resurfacing in primary TKA were highly variable among countries, as were rates of change over time. It appears that the optimal patellar resurfacing strategy may depend mostly on unique patient factors and surgeon expertise. Future studies should attempt to elucidate the individual patient characteristics that contribute to increased risks of revision or anterior knee pain to determine who will most benefit from patellar resurfacing in primary TKA.

RESUMEN

BACKGROUND: Two related recent reports described high error rates for implant positioning and reduced implant survivorship in manual unicompartmental knee arthroplasty (MUKA) compared to robotic-assisted unicompartmental knee arthroplasty (RUKA). The present study scientifically replicated these reports by comparing MUKAs similarly performed by an experienced high-volume surgeon in similar patients using the same study methods as these reports. METHODS: A total of 216 consecutive MUKAs were retrospectively evaluated radiographically for achievement of implant positioning targets. Achievement of targets was compared to the published MUKA and RUKA outcomes and correlated with revision rates and patient-reported outcome measures. RESULTS: There were 20% of study MUKAs compared to 88.1% of comparison MUKAs (P < .001) and 31.4% of comparison RUKAs (P < .048) that failed to meet all 7 implant positioning targets. The MUKA revision rates were significantly lower in the study sample than for comparison MUKAs (3.2% versus 14.2%, P < .001). Implant survivorship was 91.7% (95% confidence interval 84.9, 98.5%) at 8.9 years compared to 70.0% (95% confidence interval 56.0, 80.0%) at 10.2 years, respectively. Most patient-reported outcome measures did not differ based on achievement of implant positioning targets (P ≥ .072). CONCLUSIONS: Present study findings indicate that observations in the 2 recent reports may not be generalizable to all UKA surgeons. Additional data on the relationship between implant positioning and revision as well as functional outcomes are needed to identify appropriate robotic arthroplasty applications.

Asunto(s)

RESUMEN

BACKGROUND: Infection after aseptic revision total knee arthroplasty (TKA) has been reported from 9% to 14%. Intraosseous (IO) vancomycin infusion has decreased the risk of infection after primary TKA. The results of this additional prophylaxis were evaluated in aseptic revision TKA. METHODS: In this prospective, single-surgeon study of 20 consecutive patients having aseptic revision TKA, 500 milligrams of vancomycin in 120 mL of saline were infused into the tibia prior to incision, in addition to intravenous (IV) cefazolin. There were 18 men and 2 women who had a mean age of 67 years (range, 47-79), and mean body mass index of 34.4 (range, 25.9-51.2). The knees were aspirated in the operating room prior to IV and IO antibiotics. The outcomes were infections at 90 days requiring reoperation and complications from the infusion. RESULTS: Three of the 20 aseptic revisions had early prosthetic joint infection, 2 with gram-negative organisms and one with coagulase-negative Staphylococcus. All had debridement, liner exchange and IV antibiotic treatment, but 1 patient eventually had an above knee amputation. No patient had total body "erythema syndrome", but 1 patient had transient facial flushing. Six patients had a transient elevation of serum creatinine including 3 with an abnormal preoperative serum creatinine. CONCLUSION: In this small series of aseptic revision TKA, there was no added benefit of IO vancomycin infusion, but there were no infections with methicillin-resistant Staphylococcus aureus. Additional studies are needed before this technique should be routinely recommended.

Asunto(s)

RESUMEN

BACKGROUND: The number of total knee arthroplasties (TKA) has increased steadily with the aging of the population. This surgical procedure is recognized for its success in pain relief and restoration of knee function. However, decreased quadriceps femoris (QF) muscle strength after TKA is frequently observed but with unknown etiology. Evidence suggests that the location of the operative incision (i.e., surgical access) can influence QF muscle structure and function. The present study aimed to assess the fiber type composition, structure and assembly of the QF's vastus medialis (VM) and vastus lateralis (VL) muscles before and after TKA. METHODS: Muscle biopsies (VM and VL muscles) were collected from patients previously submitted to TKA via the medial parapatellar route and undergoing TKA revision (main group, n = 9) and patients with osteoarthrosis (OA) who were due to undergo TKA (control group: n = 18). The biopsied muscle tissue was prepared, stored, and then sectioned in a cryostat at -25 °C. The tissue sections were evaluated using routine staining techniques in pathological anatomy and histochemistry. RESULTS: The normal mosaic pattern of the medial and lateral knee muscles was observed in the main and control groups, with no evidence of peripheral nerve damage. Notably, 88.9 % of the patients exhibited mild to severe VL atrophy, while only 11.1 % of patients in the control group presented this feature (P < 0.001). CONCLUSIONS: The medial parapatellar incision for TKA surgical access does not generate definitive morphological changes in the VM and VL muscle fibers but may contribute to VL atrophy.

Asunto(s)

RESUMEN

Purpose: Three-dimensional (3D) printing technology has emerged as a new treatment method due to its precision and personalization. This study aims to explore the application of a 3D-printed personalized porous tantalum cone for reconstructing the bone defect in total knee arthroplasty (TKA) revision. Methods: Between November 2017 and October 2020, six patients underwent bone reconstruction using 3D-printed porous tantalum cones in TKA revision. The knee function was assessed using the Hospital for Special Surgery (HSS) score pre- and postoperatively. The pain was measured by the visual analog scale (VAS) pre- and postoperatively. The quality of life was measured using the 36-Item Short Form Health Survey (SF-36) to pre- and postoperatively evaluate the relief of pain. Operation time, intraoperative blood loss, postoperative drainage volume, and complications were also recorded. At the last follow-up, all patients received X-ray and computed tomography (CT) to confirm the effect of bone reconstruction. Results: After an average follow-up duration of 26.3 months, no patients developed any operation-related complications. The average intraoperative blood loss and postoperative drainage volumes were 250.1 ± 76.4 ml and 506.7 ± 300.8 ml, respectively. At the last follow-up, the HSS score was significantly higher than that before operation, indicating that the knee function was significantly improved (p < 0.001). During the follow-up, the mean VAS score decreased and the mean SF-36 score increased, both of which were significantly improved compared with preoperative conditions (p < 0.001). Radiological examination at the final follow-up showed that cones implanted into the joint were stable and bone defects were effectively reconstructed. Conclusion: This study demonstrated that 3D-printed porous tantalum cones could effectively reconstruct bone defects and offer anatomical support in TKA revision. Further studies are still needed to confirm the long-term effect of 3D-printed tantalum cones for reconstructing bone defects.

RESUMEN

In revision total knee arthroplasty, joint kinematics must be maintained amid bone and ligamentous insufficiency. Current modular designs address defects while allowing for intraoperative prosthesis customization through a variety of stem extensions and constraints. Additional constraint improves knee stability while increasing stress at the implant-host interface and modular junction of the implant. This renders the prosthetic stem-condyle junction more prone to fatigue failure. We report 2 cases of prosthetic stem-condyle junction failure in in a varus-valgus constrained revision total knee arthroplasty.

RESUMEN

BACKGROUND: Revision total knee arthroplasty (TKA) is associated with increased rates of infections, readmissions, longer operative times, and lengths-of-stay (LOS) compared to primary TKA. Additionally, increasing operative times and prolonged postoperative LOS are independent risk factors for these postoperative complications in lower extremity total joint arthroplasty (TJA). This has led to an increased effort to reduce these risk factors in order to improve patient outcomes and reduce cost. However, the relationship between operative time and LOS has not been well assessed in revision arthroplasty. Therefore, the purpose of this study was to: (I) identify predictors of longer operative times; (II) identify predictors of longer LOS; and (III) evaluate the effects of operative time, treated as both a categorical variable and a continuous variable, on LOS after revision TKA. METHODS: The NSQIP database was queried for all revision TKA cases (CPT code 27487) between 2008 and 2016 which yielded 10,604 cases. Mean operative times were compared between patient demographics including age groups, sex, and body mass indexes (BMIs). To determine predictors of LOS, mean LOS were also compared between patient demographics in the same groups. To assess the correlation of operative time on LOS, the mean LOS for 30-minute operative time intervals were compared. Univariate analysis was performed with one-way analysis of variance (ANOVA) and t-tests. A multivariate analysis with a multiple linear regression model was performed to evaluate the association of LOS with operative times after adjusting for patient age, sex, and BMI. RESULTS: The mean LOS for revision TKA was 4 (±3) days. Further analysis showed that young age is associated with increased LOS (P<0.01). An analysis of operative times showed positive correlations with young age, BMI greater than 30 and male sex (P<0.05). The mean LOS of revision TKA patients was found to increase with increasing operative time in 30-minute intervals (P<0.001). Multivariate analysis showed that longer operative times had significant associations with longer LOS even after adjusting for patient factors (ß=0.102, SE =0.001, P<0.001). These results also showed that out of all of the study covariates, operative times had the greatest effect on LOS after revision TKA. CONCLUSIONS: Revision TKA is a complex procedure, often requiring increased operative times compared to primary TKA. This study provides unique insight by correlating operative times to LOS in over 10,000 revision TKAs from a nationwide database. Our results demonstrate that out of all the study covariates (age, sex, and BMI), operative times had the greatest effect on LOS. The results from this study indicate that less time spent in the operating room can lead to shorter LOS for revision TKA patients. This relationship further underscores the need for improved preoperative planning and intra-operative efficiency in an effort to decrease LOS and improve patient outcomes.

RESUMEN

PURPOSE: Revision of unicompartmental knee arthroplasty (UKA) to total knee arthroplasty (TKA) is technically demanding but can be performed with computer navigation system guidance. The purpose of this study was (1) to compare the outcomes of revision of UKA to TKA to those of primary TKA and (2) to describe a surgical technique for the revision of UKA to TKA using a navigation system. METHODS: From May 2011 to April 2014, a total of 298 knees underwent primary navigation-assisted TKA (group 1), and navigation-assisted UKA revision to TKA was performed in 15 patients (group 2). One to three propensity score matching was performed to compare the two groups after a minimum of three years of follow-up. Radiographic and clinical outcomes in addition to radiolucent lines were evaluated during follow-up. RESULTS: In group 1, there was one case that required metal block augmentation with the long stem under the tibial plate due to severe bone loss, while in other cases, short stems were used, and cement and autogenous bone grafts were used to fill bone defects due to minimal bone loss. Pre- and post-operative outcomes were significantly improved in both groups (p < 0.001). There were no statistical differences between groups in pre- and post-operative outcomes except post-operative Knee Society Function Score (KSFS) (p = 0.008). There were no radiolucent lines in the tibia or femur in either group during follow-up. CONCLUSIONS: With the use of an appropriate surgical technique, navigation-assisted revision of UKA to TKA can yield clinical and radiologic outcomes comparable to those of primary navigation-assisted TKA. LEVEL OF EVIDENCE: Level IV.

Asunto(s)

RESUMEN

PURPOSE: Decades of innovations in total knee arthroplasty (TKA) design have led to large number of possible prosthesis combinations in regards fixation, posterior stability, bearing mobility, bearing surface, and patella resurfacing, each of which can alter the revision risk. The accumulative effect when the lowest risk combination in each design category, or "Optimum Prosthesis Combination" (OPC) is utilized remains unknown. The purpose of this analysis was to first, identify the OPC and second, to compare the revision risk of a cohort who received the OPC to a cohort who received an Alternative Prosthesis Combination (APC). METHODS: National registry revision risk data for primary TKA for osteoarthritis were obtained from September 1999 to December 2015 for two patient cohorts, those receiving an OPC and those receiving an APC. OPC was defined as TKA with the lowest revision risk option for five primary TKA design categories; fixation, posterior stability, bearing mobility, bearing surface, and patella resurfacing, while APC had one or more higher risk options. RESULTS: Of the 482,373 included TKA, 42,008 (8.7%) were in the OPC cohort, who received a minimally stabilized, fixed bearing TKA with cross-linked polyethylene with patella resurfacing. Both cohorts had similar demographics. At 10 years, the OPC cohort had a Cumulative Percent Revision of 2.4% (95% CI 2.1, 2.8) compared to 5.5% (95% CI 5.4, 5.6) for the APC cohort. For all patients, revision risk of the APC cohort was higher at all times [151% greater at ≥ 3 years (p < 0.001)]. Loosening/lysis was the most common cause of revision in the ACP cohort (1.1%), while it was the second most common cause in the OPC cohort (0.3%). The increased risk was apparent in all age and gender subgroups, with the highest risk increase seen in males ≥ 65 years. CONCLUSIONS: Patients receiving the lowest risk prosthesis design combination or Optimum Prosthesis Combination TKA had a 60% lower revision risk, with similar demographics to the Alternative Prosthesis Combination TKA. LEVEL OF EVIDENCE: III.

Asunto(s)

RESUMEN

BACKGROUND: According to literature, more than 30% of revised knee arthroplasties will require at least one re-revision. Practical experience has shown that there are considerable product-specific differences in the explantability of cemented long-stem prostheses. In the registers of successful implants, stem geometry varies considerably between the manufacturers. However, comparative data on explantability of the respective stems are missing. Objective of the present study was to identify a correlation between the geometry of a smooth cemented long stem and the necessary explantation energy required until failure of the implant-cement interface occurs. METHODS: Eight cemented stems with different conical profile angles (0°-3°) were explanted in a reproducible biomechanical setup each six times to evaluate the correlation between the stem design and the required explantation energy. RESULTS: The average explantation energy was highest in the case of the cylindrical stem, at 18.1 ± 3.6 J. At a cone angle of 0.25°, it was just 12.1 ± 2.1 J (p < 0.001) and dropped beyond 0.5° to an average of 5.7 ± 1.8 J (p < 0.001). Between 0.5° and 3°, no significant difference in the required extraction energy was observed. CONCLUSIONS: Whereas smooth conical stems can mostly be removed easily, an early decision in favour of osteotomy or fenestration can be taken in the case of cylindrical cemented stems.

Asunto(s)

RESUMEN

INTRODUCTION: Total knee arthroplasty revision (TKAr) is increasing of relevance in orthopaedic surgeon daily practice and will become more and more relevant in the future. The aim of this study is to summarize indications, complications, clinical and radiological mid-term results of metaphyseal sleeves in management of bone defects in TKAr. METHODS: A systematic review of English literature was performed on Medline. Retrospective or prospective studies with 2 years of follow-up (FU) were included. The PRISMA 2009 flowchart and checklist were considered to edit the review. Rates of intraoperative fractures, aseptic loosening, periprosthetic joint infection (PJI), reoperations and re-revisions were extrapolated by the papers. RESULTS: 13 articles with a level of evidence of IV were included in the systematic review. 1079 TKAr (1554 sleeves) with a mean FU of 4.0 ± 1.1 years were analysed. The studies showed good clinical and functional outcomes. Sleeves allowed a stable metaphyseal fixation and osseointegration with an implant and sleeves aseptic survival rate of 97.7 and 99.2%, respectively. The incidence of PJI was 2.7 ± 2.4%. The estimated rate of reoperations and re-revisions were 14.2 ± 9.2 and 7.1 ± 4.8%, respectively. CONCLUSION: Metaphyseal sleeves represent a viable option in management of types IIb and III AORI bone defects in TKAr. Further high-quality log-term studies would better clarify complications, clinical and radiological results of this promising technique in total knee arthroplasty revision.

Asunto(s)

RESUMEN

BACKGROUND: Periprosthetic joint infection (PJI) after primary total knee arthroplasty (TKA) is a devastating complication. The short-term morbidity profile of revision TKA performed for PJI relative to non-PJI revisions is poorly characterized. The purpose of this study is to determine 30-day postoperative outcomes after revision TKA for PJI, relative to primary TKA and aseptic revision TKA. METHODS: The American College of Surgeons National Surgical Quality Improvement Program from 2005 to 2015 was queried for primary and revision TKA cases. Revision TKA cases were categorized into PJI and non-PJI cohorts. Differences in 30-day outcomes including postoperative complications, readmissions, operative time, and length of stay were compared using bivariate and multivariate analyses. RESULTS: In total, 175,761 TKAs were included in this study, with 162,981 (92.7%) primary TKAs and 12,780 (7.3%) revision TKAs, of which 2196 (17.2%) revisions were performed for PJI. When compared to aseptic revision TKA, multivariate analysis demonstrated that PJI revisions had a significantly higher risk of major early postoperative complications including death (adjusted odds ratio [OR] 3.25) and sepsis (OR 8.73). In addition, nonhome discharge (OR 1.75), readmissions (OR 1.67), and length of stay (+2.1 days) were all greater relative to non-PJI revisions. CONCLUSION: Utilizing a large, prospectively collected, national database, we found that revision TKA for PJI has a greater risk of short-term morbidity and mortality and requires a higher utilization of healthcare resources. These results have implications for patient counseling and alternative payment models that may eventually include revision TKA.

Asunto(s)

RESUMEN

BACKGROUND: Prior studies comparing unicompartmental knee arthroplasty (UKA) with total knee arthroplasty (TKA) in the elderly are limited by heterogeneity in arthritic disease patterns and patient selection. We report the results of UKA and TKA in patients 75 years and older with isolated medial compartmental arthritis, with special emphasis on immediate postoperative recovery, complications, reoperation rates, and implant survivorship at midterm follow-up. METHODS: A retrospective review was performed of all patients 75 years and older who underwent UKA or TKA at our institution between 2002 and 2012. All TKA preoperative X-rays were reviewed by a blind observer to identify knees with isolated medial compartmental arthritis considered acceptable candidates for UKA. Patients with less than 2 years of follow-up, flexion contracture greater than 10°, and rheumatoid arthritis were excluded. The final sample included 120 UKA (106 patients) and 188 TKA (170 patients) procedures. Patient records were reviewed to determine early postoperative recovery, complications, reoperations for any reason, and implant survivorship. RESULTS: UKA patients experienced significantly shorter operative time, shorter hospital stay, lower intraoperative estimated blood loss, lower postoperative transfusions, greater postoperative range of motion, and higher level of activity at time of discharge. Two UKA and 2 TKA patients required revision surgery. There was no statistically significant difference in postoperative Knee Society Scores. There were no differences in 5-year survivorship estimates. CONCLUSION: Due to its less invasive nature, patients older than 75 undergoing UKA demonstrated faster initial recovery when compared to TKA, while maintaining comparable complications and midterm survivorship. UKA should be offered as an option in the elderly patient who fits the selection criteria for UKA.

Asunto(s)

RESUMEN

PURPOSE: Patients with rheumatoid arthritis (RA) and osteoarthritis (OA) may require revision total knee replacement. Few studies have compared post-operative complications, results and risk of re-revision in RA and OA patients. MATERIAL AND METHODS: Forty-five RA patients who had undergone revision TKA from 1998 to 2010 were selected and matched with 45 OA patients who had revision during the same period. Results of the use of a revision postero-stabilized implant in osteoarthritis were compared to results of its use in inflammatory arthritis. With a mean follow-up of ten years (range, 5-17 years) we determined differences in comorbidities, risk for peri-operative adverse events, functional and radiological results, and risk of subsequent re-revision, between patients suffering from OA versus RA. RESULTS: There were higher comorbidities, post-operative (<30 days) adverse events, and mortality at average ten years FU in RA than in OA patients. The mean overall changes in function scores were greater for the RA revision group when compared with the OA revision group. Taking steroids (Cox's regression, p = 0.001), and methotrexate or TNFα blockers (Cox's regression, p = 0.02) were not significant factors for radiolucent lines in RA and for loosening. At average ten years followup, patients with RA undergoing revision TKAs were not more likely to have a re-revision (4 among 45 patients; 9 %) than patients with OA undergoing revision in our department (7 patients; 15 %). CONCLUSIONS: Similar results for the knee were observed in these two forms of arthritis in spite of the fact that the initial local joint status and general health status are worse in inflammatory rheumatoid arthritis than in "degenerative" osteoarthritis. However, complications were more frequent with RA.

Asunto(s)

RESUMEN

BACKGROUND: The purpose of this study was to analyze the clinical and radiological evolution of the total knee revision arthroplasty with cemented stems in patients over 75 years. MATERIAL AND METHODS: A retrospective analysis was performed in all the subjects who underwent revision of total knee arthroplasty with cemented stems between 2008 and 2014 in our center. Twenty-seven individuals over 75 years met the inclusion criteria. We assessed the Knee Society Score and range of motion for clinical outcome. We evaluated the implant stability with radiographs through radiolucent lines according to the modified radiological scale of the Knee Society; we registered the complications and prosthetic survival. RESULTS: With an average age of our participants of 82.6 ± 4.4 years and a follow-up of 43 ± 14.4 months, we did not find any mechanical failure of the components. The functional average score was 115 ± 32 in the total KSS, of which 77 ± 17.5 points were in the KSS knee and 42 ± 24 in the KSS function. The average range of motion was 98º ± 17. Radiologically, 18 patients presented radiolucent lines, but only three needed follow-up using the modified Knee Society radiographic scoring system. CONCLUSIONS: The results revealed that cemented stems are a good method for fixation in the revision of total knee arthroplasty in people over 75 years. We observed acceptable medium-term clinical results with a low risk of radiological failure, despite the high number of radiolucencies.

Analizar la evolución funcional y radiológica de los pacientes mayores de 75 años intervenidos de cirugía de revisión de rodilla con vástagos cementados.

Asunto(s)

RESUMEN

AIMS: The aim of this study was to examine the results of revision total knee arthroplasty (TKA) undertaken for stiffness in the absence of sepsis or loosening. PATIENTS AND METHODS: We present the results of revision surgery for stiff TKA in 48 cases (35 (72.9%) women and 13 (27.1%) men). The mean age at revision surgery was 65.5 years (42 to 83). All surgeries were performed by a single surgeon. Stiffness was defined as an arc of flexion of < 70° or a flexion contracture of > 15°. The changes in the range of movement (ROM) and the Western Ontario and McMasters Osteoarthritis index scores (WOMAC) were recorded. RESULTS: At a mean follow up of 59.9 months (12 to 272) there was a mean improvement in arc of movement of 45.0°. Mean flexion improved from 54.4° (5° to 100°) to 90° (10° to 125°) (p < 0.05) and the mean flexion contracture decreased from 12.0° (0° to 45°) to 3.5° (0° to 25°) (p < 0.05). The mean WOMAC scores improved for pain, stiffness and function. In patients with extreme stiffness we describe a novel technique, which we have called the 'sloppy' revision. This entails downsizing the polyethylene insert by 4 mm and using a more constrained liner to retain stability. CONCLUSION: To our knowledge, this is the largest series of revision surgeries for stiffness reported in the literature where infection and loosening have been excluded. TAKE HOME MESSAGE: Whilst revision surgery is technically demanding, improvements in ROM and outcome can be achieved, particularly when the revision is within two years of the primary surgery. Cite this article: Bone Joint J 2016;98-B:622-7.

Asunto(s)

RESUMEN

Resumen: Antecedentes: Analizar la evolución funcional y radiológica de los pacientes mayores de 75 años intervenidos de cirugía de revisión de rodilla con vástagos cementados. Material y métodos: Mediante análisis retrospectivo, hemos revisado a 27 individuos mayores de 75 años a quienes se les ha implantado una prótesis total de rodilla de revisión con vástagos cementados en nuestro centro entre 2008-2014. Durante el seguimiento, se realizó un análisis clínico mediante la escala Knee Society Score y de movilidad de la rodilla, un análisis radiológico de la estabilidad de los implantes por medio de la escala radiológica modificada de la Knee Society, el registro de las complicaciones y la supervivencia protésica. Resultados: Con una edad media de los participantes de 82.6 ± 4.4 años y un seguimiento medio de 43 ± 14.4 meses, no hemos observado ningún caso de aflojamiento mecánico de los componentes. La valoración funcional ha sido de 115 ± 32 puntos en la escala total KSS, de los cuales 77 ± 17.5 puntos pertenecen al KSS rodilla y 42 ± 24 puntos al KSS función. El rango medio de movilidad fue de 98o ± 17. A nivel radiológico, 18 sujetos mostraron radiolucencias periprotésicas; según los criterios de la escala radiológica de la Knee Society, solo tres requirieron seguimiento clínico-radiológico estricto. Conclusiones: La cementación de los vástagos en prótesis totales de rodilla de revisión se trata de un buen sistema de fijación en personas mayores de 75 años, con elevada supervivencia del implante, buen resultado funcional y bajo porcentaje de aflojamiento radiológico a pesar de la aparición frecuente de radiolucencias.

Abstract: Background: The purpose of this study was to analyze the clinical and radiological evolution of the total knee revision arthroplasty with cemented stems in patients over 75 years. Material and methods: A retrospective analysis was performed in all the subjects who underwent revision of total knee arthroplasty with cemented stems between 2008 and 2014 in our center. Twenty-seven individuals over 75 years met the inclusion criteria. We assessed the Knee Society Score and range of motion for clinical outcome. We evaluated the implant stability with radiographs through radiolucent lines according to the modified radiological scale of the Knee Society; we registered the complications and prosthetic survival. Results: With an average age of our participants of 82.6 ± 4.4 years and a follow-up of 43 ± 14.4 months, we did not find any mechanical failure of the components. The functional average score was 115 ± 32 in the total KSS, of which 77 ± 17.5 points were in the KSS knee and 42 ± 24 in the KSS function. The average range of motion was 98o ± 17. Radiologically, 18 patients presented radiolucent lines, but only three needed follow-up using the modified Knee Society radiographic scoring system. Conclusions: The results revealed that cemented stems are a good method for fixation in the revision of total knee arthroplasty in people over 75 years. We observed acceptable medium-term clinical results with a low risk of radiological failure, despite the high number of radiolucencies.

Asunto(s)

RESUMEN

OBJECTIVE: To evaluate the value of preoperative radiographic evaluations for total knee arthroplasty (TKA) revision. METHODS: Thirty-one knees that were operated between 2006 and 2008, in a consecutive series of cases of TKA revision surgery were analyzed retrospectively. The following criteria were evaluated: number of wedges or structured bone grafts used for filling the bone defects; locations of the wedges and bone grafts used; and mean thickness of the polyethylene used. The AORI classification was previously established based on preoperative radiographs, using preestablished criteria. After the analysis, the knees were divided into four groups (I, IIA, IIB and III). RESULTS: The mean number of wedges or grafts used in each knee progressively increased among the groups (group I: 1.33; group IIA: 2; group IIB: 4.33; and group III: 4.83) (P = 0.0012). The commonest locations were medial in the tibia and posteromedial in the femur. There were no statistically significant differences in the thickness of the polyethylene used. CONCLUSION: The AORI classification for bone defects in the knee, based on preoperative radiographs, showed a correlation with increasing need to use wedges and/or structured grafts in TKA revisions. However, up to 46% of the knees in groups I and IIA presented bone defects of up to 5 mm that were not diagnosed by means of preoperative radiographs.

RESUMEN

OBJETIVO: Avaliar o valor da avaliação radiográfica pré-operatória nas revisões de artroplastias totais do joelho. MÉTODOS: Trinta e um joelhos operados no período de 2006 a 2008 em uma série consecutiva de casos de cirurgia de revisão de artroplastia total de joelho foram analisados retrospectivamente. CRITÉRIOS ANALISADOS: número de cunhas ou enxertos ósseos estruturados utilizados para preenchimento dos defeitos ósseos; localização das cunhas e enxertos ósseos utilizados e espessura média do polietileno utilizada. A classificação AORI era estabelecida previamente através de radiografias pré-operatórias segundo critérios preestabelecidos. Após a análise, os joelhos foram divididos em quatro grupos (I, IIA, IIB e III). RESULTADOS: O número médio de cunhas ou enxertos ósseos utilizados em cada joelho variou de maneira crescente entre os grupos (grupo I: 1,33; grupo IIA: 2; grupo IIB: 4,33; grupo III: 4,83) (P = 0,0012). As localizações mais comuns foram: medial na tíbia e posteromedial no fêmur. Não houve diferença estatisticamente significante na espessura do polietileno utilizado. CONCLUSÃO: A classificação AORI para defeitos ósseos no joelho baseada em radiografias pré-operatórias mostrou correlação crescente com a necessidade de utilização de cunhas e/ou enxertos estruturados na revisão de artroplastia total do joelho. Porém, até 46% dos joelhos dos grupos I e IIA apresentaram falhas ósseas de até 5mm não diagnosticadas através das radiografias pré-operatórias.

OBJECTIVE: To evaluate the value of preoperative radiographic evaluations for total knee arthroplasty (TKA) revision. METHODS: Thirty-one knees that were operated between 2006 and 2008, in a consecutive series of cases of TKA revision surgery were analyzed retrospectively. THE FOLLOWING CRITERIA WERE EVALUATED: number of wedges or structured bone grafts used for filling the bone defects; locations of the wedges and bone grafts used; and mean thickness of the polyethylene used. The AORI classification was previously established based on preoperative radiographs, using preestablished criteria. After the analysis, the knees were divided into four groups (I, IIA, IIB and III). RESULTS: The mean number of wedges or grafts used in each knee progressively increased among the groups (group I: 1.33; group IIA: 2; group IIB: 4.33; and group III: 4.83) (P = 0.0012). The commonest locations were medial in the tibia and posteromedial in the femur. There were no statistically significant differences in the thickness of the polyethylene used. CONCLUSION: The AORI classification for bone defects in the knee, based on preoperative radiographs, showed a correlation with increasing need to use wedges and/or structured grafts in TKA revisions. However, up to 46% of the knees in groups I and IIA presented bone defects of up to 5 mm that were not diagnosed by means of preoperative radiographs.

Asunto(s)