Medium-term outcomes of conventional versus short uncemented femoral stems for primary total hip arthroplasty in patients younger than 55 years.

BACKGROUND: Short stems are designed with a bone preservation philosophy in mind. This study aims to compare the outcomes/complications and survival of a collarless fully hydroxyapatite (HA)-coated conventional tapered stem and a HA-coated partial neck-retaining uncemented short stem in patients ⩽55 years old at medium-term follow-up. METHODS: We retrospectively studied 247 uncemented THAs operated between 2010 and 2014, comparing 146 patients treated with the fully HA-coated collarless stem (Group A) with 101 patients treated with a partial neck preserving, HA-coated short stem (Group B). 87 and 62 males were in groups A and B, respectively (p = 0.11). The mean age of the series was 46 years (17-55) (p =0.16). The mean follow-up of groups A and B were 9.9 (7-12) years and 9.7 (7-12) years, respectively (p =0.21). RESULTS: Mean Harris Hip Score improved from 55 to 92 in group A (p <0.001) and from 54 to 95 in group B (p <0.001), without differences between groups. Mean femoral neck length preservation in groups A and B was 13.6 (0-28) mm and 26 (11-38) mm, respectively (p =0.001). 13 (8.9%) and 1 (1%) patients in groups A and B presented postoperative complications, respectively (p =0.008). The conventional stem group had more aseptic loosening (Group A 3.4% vs. Group B 0%, p =0.06) along with more Symptomatic radiolucent lines (Group A 3.4% vs. Group B 0%, p =0.06). CONCLUSIONS: Both conventional and short stems showed excellent implant survival rates and functional outcomes at a mean follow-up of 9.8 years. However, complications and radiolucent lines were more frequent with a collarless conventional-length stem. Bone preservation of the femoral neck and diaphysis may be preferred in active young patients.

Late Periprosthetic Femoral Stress Fracture Associated with Extra-articular Deformity in a Patient with Fibrous Dysplasia: A Case Report.

CASE: In the setting of a total hip arthroplasty performed in a patient with a proximal femoral deformity, atraumatic periprosthetic femoral stress fracture may arise as a complication. We report a rare case of a late periprosthetic femoral stress fracture around a cemented stem in a patient with a history of fibrous dysplasia of the proximal femur. After a 10-year uneventful period, the patient complained about a subtle, subacute pain in his left thigh induced by exercise but not with daily axial load. Diagnosis of a nondisplaced, incomplete (i.e., only compromising the lateral femoral cortex) periprosthetic femoral stress fracture was made with plain radiographs, blood work, and bone scintigraphy. Surgical treatment consisted of a minimally invasive plate osteosynthesis bridging the femoral deformity plus percutaneous osteoperiosteal decortication. At 5-year follow-up, the patient was asymptomatic with full return to physical activity, with radiographs evidencing callus formation. CONCLUSION: Stress fractures around well-fixed femoral stems, while infrequent, should be addressed in patients with a history of severe proximal femur deformity experiencing atraumatic thigh pain.

Stenotrophomonas maltophilia Periprosthetic Joint Infection after Hip Revision Arthroplasty.

Stenotrophomonas maltophilia, a well-established opportunistic bacterium, primarily impacts healthcare settings. Infection of the musculoskeletal system with this bacterium is rare. We report on the first known case of hip periprosthetic joint infection (PJI) caused by S. maltophilia. The potential for development of a PJI caused by this pathogen should be considered by orthopaedic surgeons, particularly in patients with multiple severe comorbidities.

Anterior Center-Edge Angle Is Less Reliable Than Anterior Wall Index to Predict Anterior Coverage of the Femoral Head.

BACKGROUND: No consensus is available regarding which radiographic measurement most accurately correlates with anterior coverage of the femoral head. PURPOSE: (1) To determine the correlation between 2 measurements of anterior wall coverage: total anterior coverage (TAC) calculated from radiographs and equatorial anterior acetabular sector angle (eAASA) calculated from computed tomography (CT) scans; (2) to define the correlation between anterior center-edge angle (ACEA) and anterior wall index (AWI) with TAC and eAASA; and (3) to investigate what other radiographic metrics may help predict anterior coverage. STUDY DESIGN: Cohort study (Diagnosis); Level of evidence, 3. METHODS: The authors retrospectively reviewed 77 hips (48 patients) for which radiographs and CT scans were obtained for reasons other than hip-related pain. Mean age of the population was 62 ± 22 years; 48 (62%) hips were from female patients. Two observers measured lateral center-edge angle (LCEA), AWI, Tönnis angle, ACEA, CT-based pelvic tilt, and CT-based acetabular version, with all Bland-Altman plots within 95% agreement. Correlation between intermethod measurements was estimated with a Pearson coefficient. Linear regression was used to test the ability of baseline radiographic measurements to predict both TAC and eAASA. RESULTS: Pearson coefficients were r = 0.164 (ACEA vs TAC; P = .155), r = 0.170 (ACEA vs eAASA; P = .140), r = 0.58 (AWI vs TAC; P = .0001), and r = 0.693 (AWI vs eAASA; P < .0001). Multiple linear regression model 1 showed that AWI (ß = 17.8; 95% CI, 5.7 to 29.9; P = .004), CT acetabular version (ß = -0.45; 95% CI, -0.71 to -0.22; P = .001), and LCEA (ß = 0.33; 95% CI, 0.19 to 0.47; P = .001) were useful to predict TAC. Multiple linear regression model 2 revealed that AWI (ß = 25; 95% CI, 15.67 to 34.4; P = .001), CT acetabular version (ß = -0.48; 95% CI, -0.67 to -0.29; P = .001), CT pelvic tilt (ß = 0.26; 95% CI, 0.12 to 0.4; P = .001), and LCEA (ß = 0.21; 95% CI, 0.1 to 0.3; P = .001) accurately predicted eAASA. Model-based estimates and 95% CIs using 2000 bootstrap samples from the original data were 6.16 to 28.6 for AWI in model 1 and 15.1 to 34.26 for AWI in model 2. CONCLUSION: There was a moderate to strong correlation between AWI and both TAC and eAASA, whereas ACEA correlated weakly with the former measurements, thus not being useful to quantify anterior acetabular coverage. Other variables such as LCEA, acetabular version, and pelvic tilt may also help predict anterior coverage in asymptomatic hips.

Do nonagenarians have more complications and unplanned readmissions than octogenarians following primary THA? A retrospective cohort study.

INTRODUCTION: The performance of total hip arthroplasty in elderly patients, especially nonagenarians, is challenging due to higher patient frailty and medical comorbidities. We compared 90-day postoperative complications and unplanned readmissions between nonagenarians and octogenarians undergoing elective THA. METHODS: One hundred and eleven patients undergoing elective, unilateral THA were retrospectively analyzed. Forty-four patients were nonagenarians (Group A), and 67 patients were octogenarians (Group B). Demographic data included age, gender, body mass index (BMI), ASA score and Charlson Comorbidity Index (CCI). Frailty was defined according to the Rockwood Frailty Index. All patients underwent a thorough preoperative assessment through a specific institutional clinical pathway created for this matter. Postoperative adverse events were grouped into major or minor. A regression model was used to evaluate independent risk factors for the development of complications. RESULTS: There were no differences in the ASA score (65.9% vs. 53.7% ASA III-IV), prevalence of frailty (1% vs. 9%) and comorbidities between both groups (p > .05). The CCI was higher in nonagenarians (p = 0.007). Nonagenarians had more in-hospital complications, although most were minor (p = 0.002), none of which resulted in mortality. Ninety-day unplanned readmissions were similar between groups, with 4 (9.1%) and 6 (9%) in groups A and B, respectively (p = 1). Although age was a factor associated with the development of postoperative complications in the univariate regression model (OR 3.81, 95% CI 1.31 to 11.11, p = 0.014), it lost significance after performing the multivariate analysis (OR 2.48, 95% CI 0.78 to 7.90, p = 0.125). CONCLUSION: The age of 90 years old was not a barrier to perform elective THA safely. Nonagenarians had higher in-hospital minor complications when compared to the younger cohort. However, age over 90 years was not an independent risk factor for unplanned readmissions or mortality. Multimodal protocols of perioperative care are paramount for improving outcomes after THA in very old patients.

Intraoperative unfractionated heparin before femoral component cementation should be avoided in femoral neck fracture treated with hybrid total hip arthroplasty.

PURPOSE: To compare the incidence of perioperative thromboembolic events in femoral neck fracture (FNF) patients treated with hybrid total hip arthroplasty (THA) with intraoperative unfractionated heparin (UFH) versus a control group without intraoperative UFH before femoral component cementation. METHODS: We compared 139 cases without UFH (group A) versus 134 who received 10 UI/kg UFH (group B). Indication of UFH before cementation depended on the preferences of the anaesthesiologists in each case. We assessed intraoperative bone cement implantation syndrome (BCIS) and 30-day thromboembolic events, and 90-day and 1-year mortality. BCIS was classified as per Donaldson et al.'s classification according to the degree of hypotension, arterial desaturation or loss of consciousness. RESULTS: BCIS was observed in 51 (18%) cases, including 37 (13%) grade 1 and 14 (5%) grade 2. Forty-seven BCISs (35%) were observed in group B and 4 (3%) in group A (p < 0.001). Multivariate regression showed that intraoperative UFH (OR = 18, CI 95% 6-52) and consumption of oral anticoagulants (OR = 3.3, CI 95% 1-10) increased the risk of BCIS. Five patients further developed a 30-day pulmonary embolism in group B, while 2 presented this complication in group A (p = 0.231). No association between BCIS and 30-day thromboembolic events was found (p = 0.62). 90-day (1% each, p = 0.98) and 1-year (2% vs. 3%, p = 0.38) mortality were similar. CONCLUSIONS: BCIS was a frequent finding in FNF patients treated with hybrid THA. We found a paradoxically significant increase in BCIS with the use of UFH. Heparin did not seem to prevent BCIS, other thromboembolic events and mortality in this group of patients.

Luxación controlada de cadera en el tratamiento de la condromatosis sinovial asociada a una lesión tipo cam / Surgical hip dislocation for the treatment of synovial chondromatosis associated with a cam deformity

La condromatosis sinovial es una rara enfermedad benigna del tejido sinovial que puede causar daño articular si no se trata adecuadamente. Mientras que la lesión tipo cam provoca una fricción entre el borde acetabular y la unión cuello-cabeza femoral que puede generar un daño condrolabral y, en su evolución natural, llegar a la artrosis. El tratamiento de la condromatosis sinovial de cadera es controvertido, entre la cirugía abierta o artroscópica, pero debe incluir la extracción completa de los cuerpos libres y la sinovectomía para evitar recurrencias. Por el contrario, la lesión tipo cam puede manejarse con artroscopia en la mayoría de los casos. Presentamos un caso clínico en el que se asocian ambas patologías y que fue tratado mediante luxación controlada de cadera. La elección de la luxación controlada permite una visión completa de la articulación y se ha utilizado con éxito en casos de condromatosis sinovial asociada a la lesión tipo cam. Nivel de Evidencia: IV

Synovial chondromatosis is a rare benign disease of the synovial tissue that can cause joint damage if not properly treated. On the other hand, cam deformity causes friction between the acetabular rim and the femoral neck-head junction, which can lead to chondrolabral damage and, in its natural progression, result in osteoarthritis. The treatment of synovial chondromatosis of the hip is controversial, involving open surgery or arthroscopy, but it should include complete removal of loose bodies and synovectomy to prevent recurrences. In contrast, a cam lesion can often be managed with arthroscopy. We present a clinical case where both conditions were associated and treated with controlled hip dislocation. The choice of controlled dislocation allows for a comprehensive view of the joint and has been successfully used in cases of synovial chondromatosis associated with cam lesions. Level of Evidence: IV

Vástagos femorales cortos para el reemplazo total de cadera primario en pacientes jóvenes. Resultados clínicos y biomecánicos / Short femoral stems for primary total hip arthroplasty in young patients. Clinical and biomechanical outcomes

La artroplastia total de cadera es una cirugía eficaz para tratar la artrosis. Con el aumento de la necesidad de una mejor calidad de vida, este procedimiento se está realizando en pacientes más jóvenes. Pero, con la mayor expectativa de vida, también crece la demanda de múltiples cirugías de revisión para el mismo paciente. Esto plantea desafíos técnicos debido a la pérdida de hueso. Existe una necesidad creciente de identificar implantes duraderos y altamente funcionales que sean adecuados para la revisión futura. Aunque los vástagos femorales cementados eran la opción principal en el pasado, los vástagos femorales no cementados han logrado una fijación a largo plazo y excelentes resultados. Sin embargo, aún se pueden mejorar algunos problemas relacionados con la fijación. Los vástagos femorales cortos han sido desarrollados para abordar algunos de estos desafíos, mientras se mantienen los buenos resultados obtenidos con los vástagos convencionales. En este artículo, se analiza la experiencia tras 10 años de uso de vástagos femorales cortos en cirugías de cadera en pacientes jóvenes. Se comparan los resultados biomecánicos y la preservación ósea femoral, se reportan los resultados posoperatorios en relación con el regreso al deporte, y se evalúan las complicaciones relacionadas con su uso. El empleo de vástagos cortos en cirugía primaria de cadera brinda múltiples ventajas. La indicación de este tipo de implante está justificada en pacientes jóvenes y activos, con el objetivo de reproducir los resultados de los implantes convencionales con un menor consumo de hueso y la posibilidad de una revisión futura. Nivel de Evidencia: IV

Total hip arthroplasty is an effective surgery to treat osteoarthritis. Given the rising demand for a higher quality of life, this procedure is being performed on increasingly younger patients. However, a longer life expectancy is also tied to a higher demand for multiple revision surgeries for the same patient. This poses technical challenges due to bone loss. There is a growing need to identify durable and highly functional implants that are suitable for future revision. Although cemented femoral stems were the main option in the past, uncemented femoral stems have demonstrated long-term fixation and excellent results. However, some issues related to fixation can still be improved. Short femoral stems have been developed to address some of these challenges while maintaining the good results obtained with conventional stems. This study analyzes the experience after 10 years of using short femoral stems in hip surgeries on young patients. Biomechanical outcomes and femoral bone preservation are compared, postoperative outcomes regarding return to sports are reported, and complications related to their use are evaluated. Short stems have multiple advantages when used in primary hip surgery. The indication for this type of implant is justified in young and active patients, to reproduce the results of conventional implants with less bone consumption and the possibility of future revision. Level of Evidence: IV

Successful hip revision surgery following refracture of a modern femoral stem using a cortical window osteotomy technique: A case report and review of literature.

BACKGROUND: The ExeterTM Universal cemented femoral component is widely used for total hip replacement surgery. Although there have been few reports of femoral component fracture, removal of a broken femoral stem can be a challenging procedure. CASE SUMMARY: A 54-year-old man with a Dorr A femur sustained a refracture of a primary ExeterTM stem, two years after receiving a revision using a cement-within-cement technique (CWC) through an extended trochanteric osteotomy (ETO). The technical problems related to the CWC technique and the ETO played a major role in the stem fatigue refracture. We performed revision surgery and removed the distal cement using a cortical femoral window technique, followed by re-implantation with an uncemented, modular, distally-fixed uncemented stem. The patient experienced an uneventful postoperative recovery. CONCLUSION: Re-fracture of a modern femoral ExeterTM stem is a rare event, but technical complications related to revision surgery can lead to this outcome. The cortical window osteotomy technique can facilitate the removal of a broken stem and cement, allowing for prosthetic re-implantation under direct vision and avoiding ETO-related complications.

Short-Term Results of Osteochondral Autologous Transfer and Femoral Neck Osteochondroplasty for the Treatment of Osteochondral Lesions of the Femoral Head and Concomitant Femoroacetabular Impingement Syndrome: A Case Series.

This study aimed to analyse the initial results of five patients with symptomatic osteochondral lesions (OCL) and femoroacetabular impingement (FAI) who were treated successfully with osteochondral autologous transfer (OAT) and femoral neck osteochondroplasty (OCP) through surgical dislocation of the hip. Five patients with FAI and OCL of the femoral head who underwent surgery between 2015-2018 were studied retrospectively. All patients had a grade IV OCL, and the median defect size was 2 cm2 (interquartile range [IQR], 2-2). At the final follow-up, the modified Harris hip score showed a median value of 94 (IQR, 91-95) (P=0.04). Pain evaluation using the visual analogue scale showed a median value of 1 (IQR, 1-2) (P=0.04). Adequate graft union and healthy formation of the chondral surface were observed by magnetic resonance imaging. Although the procedure is demanding, the combination of OAT and femoral neck OCP appears to be an effective alternative in young patients.

Feasibility of total hip arthroplasty in cerebral palsy patients: a systematic review on clinical outcomes and complications.

PURPOSE: Total hip arthroplasty (THA) is a successful treatment for hip osteoarthritis secondary to hip dysplasia. However, the reported rate of complications following THA in the settings of neuromuscular diseases is high. This systematic review aimed to analyze the indications, functional outcomes and surgical failures of primary THA in cerebral palsy (CP) patients. METHODS: MEDLINE, EMBASE and the Cochrane Database of Systematic Reviews were searched, and all clinical studies focusing on THA in patients with CP from inception through March 2020 were included. The methodological quality was assessed with Guo et al.'s quality appraisal checklist for case series and case-control studies, while cohort and prospective studies were evaluated with a modified version of the Downs and Black's quality assessment checklist. RESULTS: The initial search returned 69 studies out of which 15, including 2732 THAs, met the inclusion criteria. The most frequent indication for THA was dislocated painful hip for which previous non-operative treatment had failed. Complications presented in 10 to 45% of cases. The most frequently reported complication was dislocation (1-20%), followed by component loosening (0.74-20%). Aseptic component loosening was the most frequent cause of revision surgery, followed by dislocation and periprosthetic fracture. Mean implant survival at ten years was 84% (range 81-86%). CONCLUSION: The available literature suggests that although THA is a beneficial procedure in CP patients, it has a higher rate of complications and worse implant survival than the general population.

Impaction Bone Grafting for Severe Femoral Bone Loss: Surgical Technique in Revision Total Hip Arthroplasty.

Revision total hip arthroplasty in the setting of extensive femoral bone loss poses a considerable challenge to the adult reconstructive surgeon. When the proximal femoral bone stock is deficient or absent, there are few options for reconstruction. In such cases, treatment options include distal cementless fixation (either modular or nonmodular), impaction bone grafting (IBG), a megaprosthesis, or even an allograft-prosthesis composite. Each of these procedures has advantages and disadvantages related to bone preservation, surgical timing, and complexity (depending on the learning curve). For its capacity of restoring bone stock, we have been utilizing the IBG technique at our center since August 1987. The aim of the present article was to describe a step-by-step femoral IBG procedure for severe proximal femoral circumferential bone loss, highlighting its current indications and contraindications. Description: The specific steps to perform this procedure include (1) preoperative planning; (2) positioning of the patient and surgical approach; (3) cautious removal of the previous components; (4) preparation of the bone graft; (5) implantation of the appropriate IBG revision system, restoring bone loss from distal to proximal and utilizing metal mesh as needed; (6) implantation of the new stem, bypassing the defect; and (7) aftercare with protected weight-bearing in order to avoid subsidence of the stem and periprosthetic fracture. Alternatives: There are several alternatives to the IBG technique in the setting of revision total hip arthroplasty with extensive femoral bone loss. These alternatives include distal cementless fixation (either modular or nonmodular), a megaprosthesis, or an allograft-prosthesis composite. Rationale: The rationale for use of the IBG technique is restoration of bone stock. Although this issue may be irrelevant in low-demand elderly patients, we believe it is of the utmost importance among young (i.e., <60 years old) and active patients. This technique is versatile enough to be utilized in different scenarios such as periprosthetic fracture, periprosthetic joint infection (2-stage protocols), and aseptic loosening. Expected Outcomes: We have reported favorable clinical and radiographic outcomes for the treatment of both aseptic and septic femoral component loosening. In all cases, we utilized vancomycin-supplemented impacted cancellous allograft without evidence of secondary effects with regard to bone incorporation, nephrotoxicity, or allergic reactions. Although it was initially contraindicated, we further extended the indication for this reconstruction alternative to cases of circumferential proximal bone loss with non-neoplastic bone defects of ≤15 cm, utilizing encompassing metal mesh and a bypassing long stem. Recently, we reported on poorer outcomes following IBG compared with the use of uncemented modular stems for the treatment of type B3 periprosthetic femoral fractures, with a significantly higher rate of infection and implant breakage for the former treatment. Nowadays, we advocate the use of this technique in young, active patients (i.e., <60 years old) with a femoral bone defect Paprosky grade IIIB or IV, in which reconstitution of bone stock is crucial to avoid an eventual implant failure in the long term. Important Tips: This technique requires an experienced team. This procedure should be avoided in the presence of active periprosthetic joint infection.The gluteus maximus tendon should be detached to avoid tensioning the sciatic nerve and to decrease the chance of periprosthetic femoral fracture.Massive bone loss can jeopardize correct implant orientation and restoration of biomechanics. In this scenario, surgeons might consider the intercondylar axis as a guide for femoral version.Try to avoid (if possible) trochanteric or extended trochanteric osteotomy because proximal bone stock is necessary to contain the bone grafts. In some cases, such as those in which the removal of the stem is difficult, especially with certain uncemented stem designs, an extended trochanteric osteotomy must be performed. Whether or not a cemented stem is removed, it is mandatory to remove all remaining cement in the femoral canal.Preoperative templating is a necessity to reconstruct leg length. Accurately determining the length of the mesh is the most important step to avoid shortening or overlengthening of the lower extremity.Approximately 10 cm of circumferential metal mesh should be fixed with 3 to 5 double cerclage metal wires to the remaining bone. The new femoral stem should bypass extend beyond the mesh for approximately 5 cm. If the stem does not bypass the mesh, there is an increased risk of postoperative fracture.In order to decrease the risk of intraoperative femoral fracture, the distal aspect of the femur should be secured with cerclage wires, and the proximal aspect of the femur should also be protected with cerclage wires over the mesh. As in any other complex femoral revision procedure, torsional forces in the supracondylar zone should be avoided, especially during trial or stem reduction maneuvers.Always utilize a bone graft mixed with antibiotic powder.Retrograde cementation must be done with cement that is in a more liquid state than in primary total hip arthroplasty. Acronyms & Abbreviations: PO = postoperativePMMA = polymethyl methacrylateIV = intravenousLMWH = low molecular weight heparinDVT/EP = deep vein thrombosis and extended prophylaxis.

Adverse Local Tissue Reaction Associated With Ceramic-On-Metal Bearing Surface in Primary Total Hip Arthroplasty: Report of Two Cases.

Total hip arthroplasty (THA) is one of the most common and successful surgical procedures worldwide. At the same time, it is constantly evolving, and as a consequence, advances in implant technology have led to significant improvements in the different materials of the acetabular and femoral components. The selection of bearing surfaces and their tribology are critical to achieving a successful outcome. Pseudotumors are important, and usually misdiagnosed, complications associated with hard bearing surfaces such as metal-on-metal couples. They belong to a group of reactions called adverse local tissue reaction, which can occur in the vicinity of any THA. We present 2 cases of adverse local tissue reaction associated with the use of ceramic-on-metal bearings surfaces in 2 primary THAs that were treated with modular component exchange during single-stage revision surgery. Level of Evidence: IV.

[Septic hip arthritis after a closed acetabulum fracture treated conservatively. Case report]. / Artritis séptica de cadera luego de una fractura cerrada de acetábulo tratada en forma conservadora. Reporte de caso.

Necrotizing fasciitis is a life-threatening infection. Inmediate diagnosis and treatment are essential. Acetabulum fractures are a frequent identity in older adults today, associated with low-energy trauma. The indication for surgical or conservative treatment depends on multiple factors such as the age and comorbidities of the patient, the type and location of the fracture, and the socio-economic environment. We described an unusual case of infected hematoma, secondary to a closed acetabulum fracture, which led to septic arthritis of the hip joint.

Las fracturas de acetábulo asociadas a traumatismos de baja energía, son una identidad frecuente hoy en día en los adultos mayores. La indicación del tratamiento quirúrgico o conservador, depende de múltiples factores como la edad y las comorbilidades del paciente, el tipo y localización de la fractura, y el medio socio-económico. Independientemente del tratamiento elegido, ninguno está exento de complicaciones. Se describe a continuación un paciente con una fractura de acetábulo cerrada, de tratamiento conservador, que derivó en artritis séptica de la articulación coxofemoral.

Preliminary outcomes of the cementless UNITED hip system for primary total hip arthroplasty at a minimum 2-year follow-up.

INTRODUCTION: This study aimed to report the initial results of the cementless UNITED hip system in primary total hip arthroplasty (THA) with a minimum follow-up of 2 years. METHODS: We retrospectively studied a consecutive series of 203 cementless THAs in 180 patients operated between 2015-2017. We included 89 female and 91 male patients with a mean age of 67 (28 to 89) years. The mean follow-up was 40 (29 to 62) months. Clinical outcome scores and radiographs were measured. Survival was calculated defining failure as the need for any further femoral or acetabular revision, irrespective of the reason. RESULTS: No femoral component loosening was detected. One patient had a Vancouver-B1 intraoperative periprosthetic femoral fracture treated with implant retention and cerclage wires. Two acetabular components were revised for aseptic loosening. Three patients suffered an acute infection treated with debridement, antibiotics, and implant retention. The mean Merle d'Aubigné et Postel scores improved from 13 (4 to 16) points preoperatively to 17 (12 to 18) points at the latest follow-up (p < 0.001). At a mean time of 40 months of follow-up, the survival was 99% and 100% for the acetabular and the femoral components, respectively. CONCLUSION: This cementless design showed excellent preliminary outcomes in terms of fixation and patient satisfaction, comparable to that of other well-known similar systems.

Reemplazo total de cadera en pacientes con osteosíntesis previa / Total hip replacement in patients with previous osteosynthesis

Existe literatura abundante sobre los resultados clínicos y radiográficos de un reemplazo total de cadera (RTC) primario complejo tras una conversión de osteosíntesis. La mayoría de esos reportes se refieren a la conversión de un clavo endomedular o una placa con tornillos femoral (debido a una fractura u osteotomía previa) en un RTC con un tallo de fijación distal. El objetivo de esta nota técnica es describir la realización de RTC primarios complejos sin el retiro de una placa con tornillos preexistente, o con su retiro parcial, utilizando implantes primarios. Nivel de evidencia: IV

There is abundant literature on the clinical and radiographic results of a complex primary total hip arthroplasty after osteosynthesis conversion. Most of these reports refer to conversion from an intramedullary nail or femoral plate and screws (due to a previous fracture or osteotomy) to THA with a distal fixation stem. That said, the objective of this report is to make a technical note on performing a complex primary THA without removal or with partial removal of a previous screw plate using primary implants. Level of Evidence: IV

Artroplastía total de cadera primaria con vástagos cortos en pacientes menores de 20 años / Primary total hip arthroplasty with short stems in patients under 20 years old

Introducción: El objetivo de este estudio fue analizar los resultados clínicos, radiográficos y funcionales en pacientes <20 años sometidos a artroplastia total de cadera con vástago femoral tipo 2B corto no cementado. Materiales y Métodos: Se realizó un estudio retrospectivo de 13 pacientes (16 artroplastias totales de cadera) operados entre enero de 2006 y enero de 2021. La edad media y el índice de masa corporal eran de 16.5 ± 2.5 años y 22,74 ± 4,06 kg/m2, respectivamente. El seguimiento medio fue de 43.3 meses (rango 12-128, DE ± 33.45). Se analizaron las indicaciones quirúrgicas, y los resultados funcionales y radiográficos. La supervivencia del implante se calculó con la estimación de Kaplan-Meier. Resultados: La indicación predominante fue necrosis avascular (9/16 caderas [56%]), el 66% estaba asociada al uso prolongado de corticoides. El HHS para cadera mejoró significativamente de 33 ± 16,5 a 94 ± 5,6 (p <0,001). Diez (76%) pacientes usaban dispositivos de asistencia para caminar antes de la artroplastia, pero ninguno los necesitaba al final del seguimiento. Se observó radiolucidez en un componente acetabular sin repercusión clínica hasta el final del seguimiento. No se registraron signos radiográficos de aflojamiento del componente femoral. La supervivencia del implante fue del 100% hasta el final del seguimiento. Conclusiones: La artroplastia total de cadera primaria con un vástago femoral corto no cementado en pacientes <20 años con artrosis avanzada de cadera logró resultados equiparables a los ya publicados, con la particularidad de que es un procedimiento menos invasivo y ahorra capital óseo femoral. Nivel de Evidencia: IV

Introduction: To our knowledge, there is no published literature on the outcomes of short-stem total hip arthroplasty (THA) in patients under 20 years old. This study aimed to analyze clinical, radiological, and functional outcomes in patients under 20 years of age undergoing THA with a short uncemented 2B femoral stem. Materials and Methods: We carried out a retrospective study of 13 patients (16 THAs) treated between January 2006 and January 2021. The mean age and BMI were 16.5±2.5 years and 22.74±4.06 kg/m2, respectively. The mean follow-up was 43.3 months (range 12-128, SD ± 33.45). Surgical indications, as well as functional and radiologic outcomes, were analyzed. Implant survival was calculated with the Kaplan-Meier estimate. Results: The predominant indication was avascular necrosis (9/16 hips [56%]), of which 66% were associated with prolonged use of cor-ticosteroids. Eight (50%) of the cases had undergone surgeries before the THA. The Harris hip score improved significantly from 33±16.5 to 94±5.6 (p<0.001). Ten (76%) patients required assistive devices to walk preoperatively, and no patient required them at the end of follow-up. Radiolucency was evident in one acetabular component, without clinical implications. There were no signs of femoral component loosening. The implant survival was 100% at the last follow-up. Conclusions: Short stems in primary THAs in patients under 20 years of age with advanced hip osteoarthritis showed clinical, functional, and radiological outcomes comparable to those previously reported in the literature for conventional stems, with the particularity of being less invasive and sparing femoral bone stock. Level of Evidence: IV

Secuenciación de próxima generación para la detección de patógenos en cirugía de cadera: experiencia y viabilidad diagnóstica en un centro de atención terciaria de la Argentina / Next generation sequencing for the detection of pathogens in hip surgery. Experience and diagnostic feasibility in a tertiary care center in Argentina

Introducción: El diagnóstico rápido y definitivo con identificación del patógeno es fundamental cuando hay una infección periprotésica. La secuenciación de próxima generación permite identificar el ADN en un germen determinado en poco tiempo. Hasta donde sabemos, no hay reportes sobre su empleo para el manejo de la infección periprotésica en Sudamérica. Nuestro objetivo fue demostrar la viabilidad diagnóstica de las muestras obtenidas de una serie de pacientes operados en Buenos Aires, Argentina, y analizadas con la técnica de secuenciación de próxima generación. materiales y métodos: Se analizó a una serie prospectiva de 20 pacientes sometidos a cirugía de revisión séptica y aséptica de cadera desde diciembre de 2019 hasta marzo de 2020. Se obtuvieron muestras intraoperatorias de líquido sinovial, tejido profundo y canal endomedular, que fueron enviadas para su análisis al laboratorio NexGen Microgen. Resultados: Se seleccionaron 17 pacientes, porque tenían una muestra apta para analizar. Los resultados se recibieron dentro de las 72 h de la cirugía. En un caso, el resultado de la secuenciación de próxima generación informó un germen distinto del identificado en los cultivos posoperatorios de partes blandas, esto permitió corregir la antibioticoterapia. En otro, esta técnica identificó Parabacteroides gordonii en una revisión aséptica, en otro, Morganella morganii, a partir de cultivos negativos en una revisión en un tiempo. Conclusión: Se demostró la viabilidad diagnóstica con la secuenciación de próxima generación, se pueden obtener resultados de microorganismos patógenos dentro de las 72 h posteriores a la cirugía en pacientes con infección periprotésica y cultivos negativos. Nivel de Evidencia: IV

Introduction: Early diagnosis of a periprosthetic joint infection (PJI) and identification of the pathogen are paramount. Next-generation sequencing (NGS) can identify the nucleic acids in a given germ in a short period. To our knowledge, there are no reports of its use in the management of PJI in South America. Our objective was to demonstrate the diagnostic feasibility of the NGS technique on the samples obtained from a series of patients operated on in Buenos Aires, Argentina. Materials and methods: A prospective series of 20 patients undergoing septic and aseptic hip revision surgery from December 2019 to March 2020 was analyzed. Intraoperative samples of synovial fluid, deep tissue, and intramedullary canal were obtained and sent to the NexGen Microgen laboratory (Texas, USA) for analysis. Results: Seventeen patients were finally eligible to present a sample suitable for analysis. In 100% of the samples, NGS results were obtained within 72 hours of surgery. In one case, the NGS result reported a germ different from the one identified in the postoperative soft tissue cultures, allowing antibiotic therapy to be corrected. In another case, NGS identified Parabacteroides gordonii in aseptic revision surgery. In another patient, the NGS identified Morganella morganii, in which conventional postoperative cultures were negative in single-stage revision surgery. Conclusion: In this study, we demonstrated the diagnostic feasibility of NGS, obtaining results within 72 hours immediately after surgery for pathogenic organisms in patients with PJI and negative cultures. Level of Evidence: IV