Valgus stress knee radiographs accurately anticipate the bone resection in medial unicompartmental knee arthroplasty: Protocol validation using an image-based robotic system.

PURPOSE: The objective of this study was to describe a planning method for medial unicompartmental knee arthroplasty (UKA) implantation using preoperative stress radiographs to measure the thickness of tibial and femoral bone resections and to validate this method with data from an image-based robotic surgery system. Having such method for preoperative planning would be of interest for surgeons performing UKA in order to anticipate optimal bone resection on both tibia and femoral sides. METHODS: A new planning method for medial UKA based on valgus stress knee radiographs validated it with an image-based robotic surgery system (Restoris MCK, MAKO®, Stryker Corporation) was proposed. This retrospective study involved radiographic measurements of 76 patients who underwent image-based robotic medial UKA between April 2022 and February 2023. Preoperative anteroposterior stress radiographs of the knee were used to simulate UKA implantation. The UKA technique was based on Cartier's angle and aimed at restoring the joint line. The total dimension measured was 14 mm (8 mm for minimal tibial component and polyethylene insert + 4 mm for femoral component + 2 mm for safety laxity). Bone resections were measured in the preoperative valgus stress radiographs and then against the intraoperative bone resection data provided by the robotic system. Inter- and intra-observer reliability was assessed using 25 measurements. RESULTS: The mean planned tibial resection measured in the radiographs was 4.3 ± 0.4 [2.9-5.8], while the mean robotic resection was 4.2 ± 0.5 [2.7-5.8] (mean difference = 0.15 mm, 95% confidence interval [CI] [-0.27 to 0.57]). There was a strong correlation between these two values (Pearson's rank R = 0.79, p < 0.001). Intra- and inter-observer reliability were also very strong (Pearson's rank R = 0.91, p < 0.001, and Pearson's rank R = 0.82, p < 0.001, respectively). The mean planned femoral bone resection measured in the radiographs was 2.7 ± 0.7 mm [1-4.5], while the mean robotic resection was 2.5 ± 0.9 [1-5] (mean difference = 0.21 mm, 95% CI [-0.66 to 1.08]). There was a strong correlation between these two values (Pearson's rank R = 0.82, p < 0.001). Intra- and inter-observer reliability were also strong (Pearson's rank R = 0.88, p < 0.001, and Pearson's rank R = 0.84, p < 0.001, respectively). CONCLUSION: This study describes and validates with robotic information a simple and reproducible preoperative planning method to determine femoral and tibial bone resection for medial UKA implantation using antero-posterior valgus stress knee radiographs, leaving a medial safety laxity of 2 mm. It represents a very valuable contribution to the understanding of UKA principles, which can serve to extend its indications and increase reproducibility of the surgical technique. LEVEL OF EVIDENCE: III. Retrospective cohort study.

Enhancing robotic precision in medial UKA: Image-based robot-assisted system had higher accuracy in implant positioning than imageless robot-assisted system across 292 knees.

PURPOSE: The objective of this study was to compare the degree of accuracy in implant positioning and limb alignment offered by two robot-assisted (RA) systems: an image-based robot-assisted (IBRA) versus an imageless robot-assisted (ILRA) system for the treatment of medial knee osteoarthritis with unicompartmental knee arthroplasty (UKA). METHODS: This retrospective radiographic study included medial UKAs performed between 2011 and 2023. Radiographic measurements taken preoperatively and at 1-year postoperative control visit focusing on hip-knee-ankle angle (HKA), posterior tibial slope (PTS), tibial component coronal alignment relative to Cartier's angle and restoration of proper joint line (JL) height were analyzed. Outliers for postoperative measurements were defined as follows: HKA <175° or >180°, PTS <2° or >8°, >3° or <-3° alterations in Cartier's angle and ±2 mm changes in the height of the joint line. RESULTS: The final sample consisted of 292 medial UKAs: 95 (32.5%) with an IBRA system and 197 (67.5%) with an ILRA system. Implant positioning and limb alignment were more accurate in the group of patients treated with IBRA, HKA (77.9% vs. 67.5%, p = 0.07), PTS (93.7% vs. 82.7%, p = 0.01), restoration of tibial varus relative to Cartier's angle (87.4% vs. 65%, p < 0.001) and restoration of JL height (81.1% vs. 69.5%, p = 0.04). CONCLUSION: Medial UKA surgery using an IBRA system was associated with a higher degree of accuracy in implant positioning and postoperative limb alignment as compared to an ILRA system. This is a valuable contribution to help communicate the advantages of using this surgical technique and improve its reproducibility. LEVEL OF EVIDENCE: Level III, Retrospective cohort study.

Associated patellofemoral osteoarthritis is not a contraindication for unicompartmental knee replacement. Report of one hundred ten prostheses with an average 6-year follow-up.

INTRODUCTION: Associated patellofemoral joint osteoarthritis (APFJ-OA) has typically been considered a contraindication for unicompartmental knee arthroplasty (UKA) in the treatment of femorotibial joint osteoarthritis. However, this contraindication is being challenged. The aim of this study was to assess clinical and functional outcomes, complications, and implant survival in medial or lateral UKA, regardless of clinical symptoms or radiographic signs of APFJ-OA. METHODS: This retrospective, comparative study included patients treated with medial or lateral UKA regardless of preoperative symptoms or signs of APFJ-OA, with a minimum 2-year follow-up. Intraoperatively, knees were subdivided based on APFJ-OA grade, according to the Outerbridge classification. Clinical and functional outcomes were analyzed using the 2011 Knee Society Score (KSS) at the last follow-up control. APFJ-OA was treated systematically, in a tailored, stepwise fashion according to its severity. Complications and implant survival rates were evaluated. Two-sided paired T-test, ANOVA, and Kruskal-Wallis tests were used with a significance level of 5%. RESULTS: Finally, 110 UKAs were assessed 81 (73.6%) medial and 29 (26.4%) laterals. The average follow-up was 6 years (2-19.5). According to Outerbridge, 22 knees (20%) were in grade 2, 59 (53.6%) were in grade 3, and 29 (26.4%) were in grade 4. All three groups showed a statistically significant increase in KSS scores and range of motion. There were no significant differences in clinical KSS improvement and flexion contracture between Outerbridge groups (average 35.7 and -4.9, respectively). Group 3 showed statistically significant improvement in functional KSS when compared to group 2 (68.8 vs 61.2). In maximum flexion, groups 3 and 4 did significantly better than group 2 (20° vs 15°). Three prostheses (2.7%) needed revision after 7, 8.6, and 12 years due to aseptic tibial loosening. Implant survival was 100% at 5 (64 of 64), 97% at 7 (30 of 31), 93% at 9 (14 of 15), and 89% at 12 years, respectively (8 of 9). CONCLUSION: Clinical and functional results, complications, and survival of medial or lateral UKA were not negatively affected by APFJ-OA assessed intraoperatively using the Outerbridge classification after an average follow-up of 6 years. We consider that APFJ-OA is not a contraindication for UKA when treated systematically according to its severity. LEVEL OF EVIDENCE: IV.

Effectiveness of Nail Dynamization in Delayed Union of Tibial Shaft Fractures: Relationship Between Fracture Morphology, Callus Diameter, and Union Rates.

OBJECTIVE: Dynamization has already been described as a secondary intervention for delay unions of tibial shaft fractures treated with intramedullary nailing. Although it's a common procedure, it is not widely supported in the literature. The purpose of this study was to determine the union rate of nail dynamization in cases of delayed union of diaphyseal tibial fractures, and assess the effect of fracture morphology on union rates. MATERIALS AND METHODS: We retrospectively analyzed a series of 199 consecutive tibial shaft fractures. We recorded the dynamization rate, period from nailing to dynamization, nailing to the union, the fracture pattern (according to AO/ASIF and whether it was closed or open), the callus diameter before dynamization (fracture healing index; FHI) and union/failure rates. RESULTS: Out of a total of 199 fractures treated during the study period, 41 (20.6%) were dynamized. After applying inclusion and exclusion criteria, 39 patients with 39 fractures were included in the study. The mean time from nailing to dynamization was 18.4 ± 7.2 weeks. The union rate was 92.3% (n = 36) over a mean time of 14.1 ± 5.6 weeks as from dynamization. The overall failure rate was 6.7% (n = 3). There was no significant association between failure and AO/ASIF classification (p > 0.05) or fracture exposure (X 2 = 0.19; p = 0.66). The pre-dynamization FHI of ≥ 1.17 was significantly associated with consolidation (p < 0.05). CONCLUSION: In cases of delayed union of tibial fractures, dynamization offered a high union rate associated with pre-dynamization FHI, while fracture morphology did not affect the failure rate.

Ultrasound Can Determine Joint Distraction During Hip Arthroscopy but Fluoroscopic-Guided Portal Placement Is Superior.

Purpose: To compare joint distraction measured on ultrasound (US) with joint space width (JSW) measured on fluoroscopy in hip arthroscopy and to determine whether ultrasound guidance is as safe and effective as fluoroscopy, the current gold standard, for establishing arthroscopic portals. Methods: Cadaveric whole-body specimens were positioned supine and subjected to 60 lbs. of unilateral axial traction using a distal femoral Steinman pin. Joint distraction was measured via JSW on fluoroscopic and ultrasound images. A single, fellowship-trained orthopaedic surgeon established anterolateral arthroscopy portals via ultrasound or fluoroscopic guidance in a randomized sequence. Total procedure time, number of times the spinal needle pierced the capsule, and iatrogenic chondral or labral injury were recorded. Results: Twelve full-body specimens (20 hips) underwent distraction, and 17 hips underwent portal placement with fluoroscopic (n = 8) or ultrasound (n = 9) guidance. JSW measured on ultrasound was significantly less laterally (13.0 vs 9.2 mm, P < .001), apically (16.7 vs 9.2 mm, P < .001), and medially (17.9 vs 9.2 mm, P < .001). Successful portal entry was achieved in every specimen. Average procedure time was 133 ± 51 seconds for the fluoroscopy group and 371 ± 260 seconds for the ultrasound group (P = .026). Fluoroscopic guidance required significantly less needle insertion attempts at 1.13 compared with 3.33 attempts for ultrasound (P = .022). Labral damage was greater in the ultrasound group at 66.67% compared with 12.50% for fluoroscopy (P = .0497). Conclusions: Joint distraction measured on ultrasound can be used to subjectively determine if the joint is adequately distracted in hip arthroscopy. Ultrasound-guided portal placement was associated with more needle insertion attempts, iatrogenic injury of the labrum, and overall procedure time in comparison to fluoroscopic guidance. Clinical Relevance: Fluoroscopy is the gold standard to confirm adequate joint distraction, aid in establishing arthroscopy portals, and evaluate resection of the femoral head during hip arthroscopy but exposes the patient to ionizing radiation, requires additional operators in the operating room, and involves the need for a heavy lead shield. Alternatives to fluoroscopy are needed, but ultrasound has not proven superior in our cadaveric model.

Reemplazo unicompartimental bilateral de rodilla en un tiempo quirúrgico. Resultados a mediano plazo de 86 prótesis con un seguimiento promedio de 6.2 años / Bilateral simultaneous unicompartmental knee arthroplasty. Medium-term outcomes in 86 arthroplasties with an average follow-up of 6.2 years

Objetivo: Evaluar los resultados funcionales, las complicaciones y la supervivencia a mediano plazo de la prótesis unicompartimental bilateral medial o lateral de rodilla en un tiempo quirúrgico. Materiales y Métodos: Estudio retrospectivo de pacientes con prótesis unicompartimental bilateral medial o lateral de rodilla colocada en un tiempo quirúrgico por gonartrosis entre abril de 2004 y abril de 2020, seguimiento mínimo 1 año. Se evaluaron los resultados clínico-funcionales con el KSS 2011. Se determinaron los tiempos quirúrgico total y de internación, y el requerimiento de transfusiones. Se analizaron las complicaciones a corto y mediano plazo, y las tasas de revisión y de supervivencia de la prótesis. Resultados: Se evaluaron 86 prótesis unicompartimentales en 43 pacientes (seguimiento promedio 6.1 años). El KSS clínico y funcional aumentó de 46,1 ± 10,2 a 80,9 ± 15,9 y de 22,8 ± 11,9 a 89,8 ± 18,9, respectivamente. La flexión máxima mejoró de 106,3° ± 5,2° a 125,1° ± 4,2° y la contractura en flexión, de 7,5° ± 2,2° a 2,3° ± 1,6°. La cirugía duró 178.6 min y la internación, 39.8 h. Dos pacientes requirieron transfusión. La tasa de complicaciones fue del 6,9%, todas menores. Tres rodillas tuvieron un aflojamiento mecánico aséptico y requirieron revisión a prótesis total de rodilla o nueva prótesis unicompartimental tras 12, 8.6 y 7 años. La supervivencia de la prótesis fue del 96,5%. Conclusión: La prótesis unicompartimental bilateral medial o lateral en un tiempo quirúrgico para la gonartrosis unicompartimental de rodilla proporciona excelentes resultados clínico-funcionales, con bajas tasas de complicaciones. Nivel de Evidencia: IV

Objective: The purpose of this article is to examine the functional outcomes, complications, and medium-term survivorship of medial or lateral bilateral simultaneous unicompartmental knee arthroplasty (bUKA) for the treatment of bilateral knee osteoarthritis. Materials and Methods: Retrospective report of patients who underwent a medial or lateral bUKA for treatment of bilateral knee osteoarthritis between April 2004 and April 2020, with a minimum follow-up of 1 year. The KSS 2011 was used for the clinical-functional evaluation of each patient. The duration of surgery, length of hospital stay, and transfusion requirements were determined. The short-term and medium-term complications were analyzed, as well as the revision rate and the prosthesis survivorship. Results: We evaluated 86 bUKAs in 43 patients with a mean follow-up of 6.1 years. The clinical and functional KSS improved from 46.1 ± 10.2 to 80.9 ± 15.9 and 22.8 ± 11.9 to 89.8 ± 18.9 respectively. Postoperative maximal flexion improved from 106.3º ± 5.2º to 125.1º ± 4.2º and flexion contracture improved from 7.5º ± 2.2º to 2.3º ± 1.6º. The mean surgical time was 178.6 minutes and the hospital stay was 39.8 hours. Two patients required transfusions. The complication rate was 6.9%. Three knees (3.5%) required revision surgery for aseptic loosening after 7, 8.6 and 12 years. The survivorship rate was 96.5%. Conclusion: Simultaneous medial or lateral bUKA provides excellent clinical-functional outcomes with a low rate of complications in patients with bilateral knee osteoarthritis. Level of Evidence: IV

Prótesis unicompartimental lateral de rodilla en el tratamiento del genu valgo artrósico. Resultados en 29 artroplastias con un seguimiento promedio de 6.2 años / Lateral unicompartmental knee arthroplasty for the treatment of lateral knee osteoarthritis. Results in 29 arthroplasties with an average follow-up of 6.2 years

Objetivo: Evaluar, de manera retrospectiva, los resultados funcionales y la supervivencia a mediano plazo de la prótesis unicompartimental lateral de rodilla para tratar el genu valgo artrósico. materiales y métodos: Estudio observacional retrospectivo. Se analizaron los casos operados con prótesis unicompartimental lateral de rodilla por genu valgo artrósico entre enero de 1999 y enero de 2019, seguimiento mínimo de un año. Se evaluaron los resultados clínicos y funcionales mediante el KSS 2011, el grado de artrosis en el compartimento externo y su progresión en el compartimento contralateral con la clasificación de Kellgren y Lawrence, y la condropatía femororrotuliana mediante la clasificación de Outerbridge modificada. Se determinaron la incidencia de complicaciones y la supervivencia de la prótesis. Resultados: Se evaluaron 29 prótesis unicompartimentales laterales de rodilla en 27 pacientes, con un seguimiento promedio de 6.2 años. El KSS clínico y funcional se incrementó de 56,5 ± 9,8 a 91,9 ± 5,3 y de 33,9 ± 13,7 a 91,4 ± 10,3, respectivamente, (p <0,001). La flexión máxima mejoró de 106,6º ± 6,7º a 124,2º ± 2,4º y la contractura en flexión, de 5,2º ± 3,2º a 1º ± 1,6º (p <0,001). El eje preoperatorio fue de 12,3º ± 4,1º de valgo, para un posoperatorio de 5,2º ± 3,1º de valgo (p <0,001). La supervivencia de la prótesis fue del 100%, con un caso de progresión artrósica en el compartimento medial (3,4%). Conclusión: La prótesis unicompartimental lateral de rodilla representa una alternativa válida y definitiva para tratar la patología artrósica femorotibial externa. Nivel de Evidencia: IV

Objective: The purpose of this article is to examine the medium-term functional outcomes and survivorship of lateral unicompartmental knee arthroplasty in the treatment of lateral knee osteoarthritis. Materials and Methods: Retrospective report. We selected and analyzed all patients who had undergone a lateral unicompartmental knee arthroplasty for the treatment of lateral knee osteoarthritis between January 1999 and January 2019, with a minimum follow-up of 1 year. The KSS score system 2011, the Kellgren-Lawrence osteoarthritis classification, the Outerbridge femoropatellar chondropathy classification and serial radiographs were used in the evaluation of each patient. The complication and prosthesis survivorship rates were assessed. Results: We identified 29 lateral unicompartmental knee arthroplasties in 27 patients with a follow-up of 6.2 years (1-19.5). The clinical and functional KSS improved from 56.5 ± 9.8 to 91.9 ± 5.3 and 33.9 ± 13.7 to 91.4 ± 10.3 respectively (p<0.001). Postoperative maximal flexion improved from 106º ± 6.7º to 124.2º ± 2.4º and flexion contracture improved from 5.2º ± 3.2º to 1º ± 1.6º (p<0.001). The average preoperative alignment was 12.3º ± 4.1º of valgus angulation, which was corrected to 5.2º ± 3.1º of valgus (p<0.001). The survivorship rate was 100% and only one patient showed osteoarthritic changes in the medial compartment (3.4%). Conclusion: Lateral unicompartmental knee arthroplasty provides excellent medium-term results. It represents a reliable and definitive option in the treatment of the isolated lateral knee osteoarthritis. Level of Evidence: IV

Estudio retrospectivo comparativo entre aspirina y dabigatrán en la incidencia de efectos tromboembólicos en pacientes con artroplastia de cadera y rodilla / Comparative retrospective study between aspirin and dabigatran in the incidence of thromboembolic events in hip and knee arthroplasty

Objetivo: Analizar la incidencia de eventos tromboembólicos extrahospitalarios luego de un reemplazo total de rodilla o cadera primario en los primeros 90 días posoperatorios, utilizando como tromboprofilaxis ácido acetilsalicílico o dabigatrán. El objetivo secundario fue evaluar el costo de la terapia antiagregante y de la anticoagulante. Materiales y Métodos: Se realizó un estudio observacional retrospectivo en el posoperatorio de reemplazos totales de cadera y rodilla primarios sobre la incidencia de eventos tromboembólicos extrahospitalarios, durante los primeros 90 días posteriores a la cirugía, en dos grupos. Se administró ácido acetilsalicílico (325 mg/día) o dabigatrán (150-220 mg/día) por 35 días. Resultados: La serie incluyó a 224 pacientes (media de la edad 68.5 años), el 44,2% eran hombres. El 51,3% era un reemplazo total de cadera. El 64,3% continuó la tromboprofilaxis con dabigatrán y el 35,7%, con aspirina. La incidencia total de eventos tromboembólicos fue del 1,3%; 1,4% con dabigatrán y 1,3% con aspirina (p = 0,9). El costo de la tromboprofilaxis fue de USD 3,6 con aspirina 325 mg y USD 130 o 175 con dabigatrán, según la presentación de 75 y 110 mg. Conclusiones:La aspirina como tromboprofilaxis tras un reemplazo total de cadera o rodilla en pacientes con bajo riesgo de sufrir eventos tromboembólicos ha logrado resultados clínicos similares a los del dabigatrán. Se puede recomendar un protocolo multimodal basado en el uso de aspirina. Este mejora el cumplimiento de la terapia antitrombótica por parte de los pacientes, debido al bajo costo de la profilaxis con aspirina. Nivel de Evidencia: III

Objective: To analyze the incidence of out-of-hospital thromboembolic events after a primary total knee or hip replacement in the first 90 postoperative days, using acetylsalicylic acid or dabigatran as thromboprophylaxis. As a secondary objective, to evaluate the cost of antiplatelet therapy compared to anticoagulants. Materials and Methods: A retrospective observational study was carried out in the postoperative period of primary total hip and knee replacement on the incidence of out-of-hospital thromboembolic events during the first 90 postoperative days in two groups of patients. Acetylsalicylic acid (325 mg per day) or dabigatran (150 to 220 mg per day) were used as thromboprophylaxis for 35 days. Results: The series consisted of 224 patients aged 68.5 years (38-95 years), 44.2% male. 51.3% corresponded to total hip replacement. 64.3% continued thromboprophylaxis with dabigatran and 35.7% with aspirin. The total incidence of thromboembolic events was 1.3%. In the patients who received dabigatran it was 1.4% and in those who received aspirin, 1.3% (p = 0.9). The cost of thromboprophylaxis with aspirin 325 mg was US $ 3.6 while with dabigatran it was US $ 130 or $ 175, according to its presentation, 75 and 110 mg. Conclusion: Aspirin as thromboprophylaxis after total hip or knee replacement in individuals at low risk of thromboembolic events has shown similar clinical outcomes as dabigatran, and a multimodal protocol based on the use of aspirin can be recommended. This improves patient adherence to antithrombotic therapy, due to the low cost of aspirin prophylaxis. Level of Evidence: III

Paciente con síndrome de Klippel-Trenaunay. Reporte de un caso de reemplazo articular de cadera suspendido durante la cirugía / Patient with Klippel-Trenaunay syndrome. Case report of an intraoperatively aborted hip joint replacement

El síndrome de Klippel-Trenaunay es un trastorno congénito infrecuente. Por lo general, afecta uno de los miembros inferiores. Los hallazgos típicos son angiomas, malformaciones venosas, várices hipertróficas con comunicaciones arteriovenosas e hipertrofia del miembro afectado que, en algunos casos, altera la estructura ósea. El objetivo de esta presentación es describir el caso de un paciente de 54 años en el que se programó un reemplazo articular de la cadera izquierda durante un año y la cirugía debió suspenderse por el riesgo de exanguinación, y analizar la bibliografía al respecto. Nivel de Evidencia: IV

Klippel-Trenaunay Syndrome is a rare congenital disorder. It usually affects one of the lower limbs. It is characterized by the presence of angiomas, venous malformations, hypertrophic varices with arteriovenous communications and hypertrophy of the affected limb, altering in some cases the bone structure. The aim of this presentation is to describe the case of a 54-year-old patient for whom a joint replacement of the left hip had been scheduled for one year and the surgery had to be aborted due to the risk of exsanguination of the patient, and to analyze the literature in this regard. Level of Evidence: IV