Impedance Control Strategies for Enhancing Sloped and Level Walking Capabilities for Individuals with Transfemoral Amputation Using a Powered Multi-Joint Prosthesis.

INTRODUCTION: Powered prostheses are a promising new technology that may help people with lower-limb loss improve their ability to perform locomotion tasks. Developing active prostheses requires robust design methodologies and intelligent controllers to appropriately provide assistance to the user for varied tasks in different environments. The purpose of this study was to validate an impedance control strategy for a powered knee and ankle prosthesis using an embedded sensor suite of encoders and a six-axis load cell that would aid an individual in performing common locomotion tasks, such as level walking and ascending/descending slopes. MATERIALS AND METHODS: Three amputees walked on a treadmill and four amputees walked on a ramp circuit to test whether a dual powered knee and ankle prosthesis could generate appropriate device joint kinematics across users. RESULTS: Investigators found that tuning 2-3 subject-specific parameters per ambulation mode was necessary to render individualized assistance. Furthermore, the kinematic profiles demonstrate invariance to walking speeds ranging from 0.63 to 1.07 m/s and incline/decline angles ranging from 7.8° to 14°. CONCLUSION: This work presents a strategy that requires minimal tuning for a powered knee & ankle prosthesis that scales across a nominal range of both walking speeds and ramp slopes.

Loosening and revision rates after total shoulder arthroplasty: a systematic review of cemented all-polyethylene glenoid and three modern designs of metal-backed glenoid.

BACKGROUND: Several modern designs of metal-backed glenoids (MBG) have been devised to overcome flaws such as loosening and a high failure rate. This review aimed to compare rates of complications and revision surgeries between cemented polyethylene glenoid (PEG) and three examples of modern MBG designs. METHODS: Literature search was carried out using PubMed, Cochrane Library, EMBASE, and Google Scholar using MeSH terms and natural keywords. A total of 1186 articles were screened. We descriptively analyzed numerical data between the groups and statistically analyzed the categorical data, such as the presence of radiolucent line, loosening, and revision surgery (failure). Articles were divided into three groups based on follow-up duration: < 36-month, 36-72-month, and > 72-month subgroups. RESULTS: This study included 35 articles (3769 shoulders); 25 on cemented PEG and ten on the modern MBG. Mean age was 66.4 (21-93) and 66.5 years (31-88). The mean duration of follow-up was 73.1 (12-211) and 56.1 months (24-100). Overall, the rate of the radiolucent line was 354/1302 (27%) and 47/282 (17%), the loosening rate was 465/3185 (15%) and 22/449 (5%), and the failure rate was 189/3316 (6%) and 11/457 (2%), for PEG and MBG, respectively. The results of < 36-month and 36-72-month subgroups showed lower rates of radiolucency and loosening in the cemented PEG group, but there was no significant difference in failure rate (P = 0.754 and 0.829, respectively). In the > 72-month subgroup, MBG was better in terms of loosening (P < 0.001) and failure rates (P = 0.006). CONCLUSIONS: The modern MBG component, especially TM glenoid, seems to be a promising alternative to cemented PEGs, based on subgroup revision rates according to the follow-up duration and overall results of ROM and clinical scores. All polyethylene glenoids tend to increase loosening and failure over time. Three modern MBG designs seem to have no difference in failure, at least in the < 36-month and 36-72-month subgroups compared to the cemented PEG. More long-term follow-up studies on modern MBG should be ultimately conducted. LEVEL OF EVIDENCE: Level IV, systematic review.

Precision of Bone Mineral Density Measurements Around Total Ankle Replacement Using Dual Energy X-ray Absorptiometry.

INTRODUCTION: Joint prosthesis survival is associated with the quality of surrounding bone. Dual-energy X-ray absorptiometry (DXA) is capable to evaluate areal bone mineral density (BMD) around different prosthetic implants, but no studies evaluated periprosthetic bone around total ankle replacement (TAR). Our aim is to determine the precision of the DXA periprosthetic BMD around TAR. METHODOLOGY: Short-term precision was evaluated on 15 consecutive patients. Each ankle was scanned 3 times both in the posteroanterior (PA) and lateral views with a dedicated patient positioning protocol. Up to four squared regions of interest (ROIs) were placed in the periprosthetic bone around tibial and talar implants, with an additional ROI to include the calcaneal body in the lateral scan. Coefficient of variation (CV%) and least significant change were calculated according to the International Society for Clinical Densitometry. RESULTS: The lateral projection showed lower mean CV values compared to the PA projection, with an average precision error of 2.21% (lateral scan) compared to 3.34% (PA scans). Overall, the lowest precision error was found at both "global" ROIs (CV = 1.25% on PA and CV = 1.3% on lateral). The highest CV value on PA was found at the medial aspect of talar side (ROI 3; CV = 4.89%), while on the lateral scan the highest CV value was found on the posterior aspect of talar side (ROI 2; CV = 2.99%). CONCLUSIONS: We found very good reproducibility BMD values of periprosthetic bone around TAR, that were comparable or even better compared to other studies that evaluated periprosthetic BMD around different prosthetic implants. DXA can be used to precisely monitor bone density around ankle prostheses, despite further long-term longitudinal studies are required to assess the clinical utility of such measurements.

Current Practice Patterns of Fellowship-Trained Arthroplasty Surgeons: Has the Influence of Fellowship Training Been Undervalued?

BACKGROUND: As the clinical and financial environments of total joint arthroplasty (TJA) have evolved over the last several decades so has the role of the surgeon in providing this care to patients. Our objective was to examine current practices and influential factors among fellowship-trained arthroplasty surgeons. METHODS: An electronic survey was sent to all surgeons who had completed one of the three high-volume adult reconstruction fellowships from the years 2007-2016. The survey consisted of 34 questions regarding current practice characteristics, case volumes for primary and revision total hip arthroplasty (THA) and total knee arthroplasty (TKA), use of advanced technologies, choice of surgical approach and implant design, factors influencing their choices, and their involvement in implant selection and contract negotiations. RESULTS: Questionnaires were sent to 53 surgeons; 52 were completed. Sixty percent of respondents performed at least 100 TKAs and 84% performed at least 50 THAs annually. Ninety-four percent use a single company's implant for more than 90% of primary TKA and THA. Fellowship or residency experience was the most significant influence on TKA and THA implant selection for 62% and 45% of surgeons, respectively, while contracts of their current institution were the primary influence for 17% and 12%, respectively. Fifty-five percent of surgeons used some advanced technology of which 16% said this influenced their implant choice. Eighty-six percent perform the majority of cases at centers performing at least 200 TJAs per year, and 39% participate in implant contract negotiations. CONCLUSION: Despite changes in the economic environment of TJA, this study demonstrates that experience with a specific implant during training, particularly fellowship, is the most influential factor for implant selection among fellowship-trained arthroplasty surgeons.

Radiological changes do not influence clinical mid-term outcome in stemless humeral head replacements with hollow screw fixation: a prospective radiological and clinical evaluation.

BACKGROUND: Stemless shoulder arthroplasty is a fairly new concept. Clinical and radiological follow-up is essential to prove implant safety and concept. This prospective single-centre study was performed to evaluate the influence of radiological changes on clinical mid-term outcome following stemless humeral head replacement with hollow screw fixation. METHODS: Short- and mid-term radiological and clinical evaluations were performed in 73 consecutive shoulders treated mainly for idiopathic and posttraumatic osteoarthritis with stemless humeral head arthroplasty including 40 hemi- (HSA) and 33 total shoulder arthroplasties (TSA). Operating times of stemless implantations were compared to 110 stemmed anatomical shoulder prostheses. Appearances of humeral radiolucencies or radiological signs of osteolysis or stress shielding were assessed on standardized radiographs. Patients' clinical outcome was evaluated using the Constant score and patients' satisfaction was documented. RESULTS: Radiological changes, detected in 37.0%, did not affect clinical outcome. Constant scores significantly improved from baseline to short and mid-term follow-up (p < 0.001). The majority of patients (96.2%) were satisfied with the procedure. No loosening of the humeral head component was detected during a mean follow-up of 58 months. Operating times were significantly shorter with stemless compared to stemmed implants (p < 0.001). CONCLUSIONS: Clinical mid-term outcome after stemless humeral head replacement was not affected by radiological changes. TRIAL REGISTRATION: The institutional review board (St. Vincent Hospital Vienna; 201212_EK01; date of issue: 11.12.2012) approved the study. The trial was registered at ClinicalTrials.gov ( NCT02754024 ). Retrospective registration.

Bone and Joint Medical Devices: Methods, Models, and Regulations.

Repair of bone and joint tissue to restore normal function is a unique endeavor that requires recreating tissue structure and the integrated healing of both organic and inorganic tissue components. Session 5 (Structural approaches to bone and joint repair) at the 36th annual Society of Toxicologic Pathology Annual Symposium included 2 talks covering methods, models, and regulatory considerations used to evaluate novel approaches for repairing bones and joints. Lyn Wancket provided a general overview of medical devices, with an emphasis on preclinical and clinical evaluations of bone and joint devices. Karen Manhart outlined regulatory review of medical devices by the Food and Drug Administration. This summary includes highlights from both talks.

Long-term Results of Scandinavian Total Ankle Replacement.

BACKGROUND: The purpose of this study was to evaluate the long-term results of the Scandinavian Total Ankle Replacement (STAR) implant in a single center. METHODS: Between 1997 and 2002, 34 consecutive ankles were replaced with the STAR ankle prosthesis and reviewed in 2016. Patients were followed both radiologically and clinically; clinical outcomes were measured with the Kofoed ankle score and subjective measurements. The median follow-up period was 159 months (13.3 years; range, 13-202 months). RESULTS: The implant survival rate was 93.9% (95% confidence interval [CI], 92.2%-86.7%) at 5 years, 86.7% (95% CI, 69.3%-96.2%) at 10 years, and 63.6% (95% CI, 30.8%-89.0%) at 15 years. A total of 15 ankles (44%) had been revised: 2 by fusion, 3 by further replacement, 5 by insert exchange, and 5 by bone grafting for marked osteolysis. The improvements in the Kofoed ankle score and Kofoed ankle score for pain were statistically significant at every postoperative evaluation point compared to the preoperative values (all P < .0001), and subjective patient satisfaction was high. CONCLUSION: Our results were satisfactory and in agreement with previously reported findings of STAR implants. LEVEL OF EVIDENCE: Level IV, retrospective case series.

[Endoprostheses in geriatric traumatology]. / Endoprothetik in der Alterstraumatologie.

BACKGROUND: Geriatric traumatology is increasing in importance due to the demographic transition. In cases of fractures close to large joints it is questionable whether primary joint replacement is advantageous compared to joint-preserving internal fixation. OBJECTIVE: The aim of this study was to describe the importance of prosthetic joint replacement in the treatment of geriatric patients suffering from frequent periarticular fractures in comparison to osteosynthetic joint reconstruction and conservative methods. MATERIAL AND METHODS: A selective search of the literature was carried out to identify studies and recommendations concerned with primary arthroplasty of fractures in the region of the various joints (hip, shoulder, elbow and knee). RESULTS: The importance of primary arthroplasty in geriatric traumatology differs greatly between the various joints. Implantation of a prosthesis has now become the gold standard for displaced fractures of the femoral neck. In addition, reverse shoulder arthroplasty has become an established alternative option to osteosynthesis in the treatment of complex proximal humeral fractures. Due to a lack of large studies definitive recommendations cannot yet be given for fractures around the elbow and the knee. Nowadays, joint replacement for these fractures is recommended only if reconstruction of the joint surface is not possible. CONCLUSION: The importance of primary joint replacement for geriatric fractures will probably increase in the future. Further studies with larger patient numbers must be conducted to achieve more confidence in decision making between joint replacement and internal fixation especially for shoulder, elbow and knee joints.

[Treatment of Osteochondral Lesions in the Ankle: A Guideline from the Group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Traumatology (DGOU)]. / Behandlung osteochondraler Läsionen des Sprunggelenks: Empfehlungen der Arbeitsgemeinschaft Klinische Geweberegeneration der DGOU.

Background: Osteochondral lesions (OCL) of the ankle are a common cause of ankle pain. Although the precise pathophysiology has not been fully elucidated, it can be assumed that a variety of factors are responsible, mainly including traumatic events such as ankle sprains. Advances in arthroscopy and imaging techniques, in particular magnetic resonance imaging (MRI), have improved the possibilities for the diagnosis of OCLs of the ankle. Moreover, these technologies aim at developing new classification systems and modern treatment strategies. Material and Methods: This article is a review of the literature. Recommendations of the group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Traumatology (DGOU) for the treatment of OCLs of the ankle are presented. The review gives a concise overview on the results of clinical studies and discusses advantages and disadvantages of different treatment strategies. Results: Non-operative treatment shows good results for selected indications in children and adolescents, especially in early stages of osteochondritis dissecans (OCD). However, surgical treatment is usually indicated in OCLs in adolescents and adults, depending on the size and location of the lesion. Various arthroscopic and open procedures are frequently employed, including reattachment of the fragment, local debridement of the lesion with fragment removal and curettage of the lesion, bone marrow-stimulation by microfracture or microdrilling (antegrade or retrograde), and autologous matrix-induced chondrogenesis (AMIC®) - with or without reconstruction of a subchondral bone defect or cyst by autologous cancellous bone grafting. Isolated subchondral cysts with an intact cartilage surface can be treated by retrograde drilling and possibly additional retrograde bone grafting. For larger defects or as salvage procedure, osteochondral cylinder transplantation (OATS® or Mosaicplasty®) or matrix-induced autologous chondrocyte transplantation (MACT) are recommended. Transplantation of so-called (osteochondral) mega grafts, such as autologous bone grafts or allografts, are used for very large osteochondral defects that cannot be reconstructed otherwise. Implantation of the so-called "small metal implants" - such as HemiCAP Talus® - is reserved for selected cases after failed primary reconstruction. Corrective osteotomies are indicated in accompanying axial malalignments. Conclusions: There are several different treatment strategies for OCLs, but clinical studies are rare and evidence is limited. Therefore, interventional studies, e.g. randomised controlled trials (RCTs), but also observational studies, e.g. based on data of the Cartilage Registry of the German Society of Orthopaedics and Traumatology (www.knorpelregister-dgou.de), are needed and are recommended by the authors.

[Total Joint Replacement and Return to Sports]. / Endoprothetischer Gelenkersatz und Sport.

Background: An increasing number of physically active patients not only need to know if they will basically be able to engage in sports after undergoing arthroplasty. They also would like to know whether or not they will be able to resume their preoperative activity levels. This article aims to provide an overview of recent data regarding the following questions on hip, knee and shoulder arthroplasty: (1) What is the impact of physical activity on an endoprosthesis? (2) What level of sports can be achieved after an arthroplasty procedure? (3) What types of sport are recommended for patients with an endoprosthesis? Methods: PubMed-based review of the literature. Narrative review focusing on current data from the years 2010 to 2016. Results: The commonly known recommendation to exercise low-impact sports such as hiking, swimming, cycling or golf at a moderate intensity remains valid for all types of prostheses in all joints. There is broad consensus that the benefits of these sports outweigh the negative effects. Having undergone total hip or knee arthroplasty, most patients with a high preoperative activity level return to sports after 3-6 months, albeit with a clear tendency to lower intensity and a shift from high-impact to low-impact sports. Some key questions have to be answered regarding the effects of low-impact sports that are exercised with high intensity, the effects resulting from high-impact sports, effects specific to different types of sport, and possibilities provided by different prosthesis types. In this context, a lot remains to be done to investigate the limits between positive and negative effects resulting from physical activity of varying intensity. New data suggests that generally a higher physical performance level may be achieved than has been traditionally recommended. Early results of unicondylar knee prostheses are far better than those achieved with bicondylar prostheses. In contrast to expert recommendations, shoulder endoprostheses show the highest postoperative activity levels after inverted arthroplasty, followed by anatomic arthroplasty, and the lowest activity level after the implantation of a hemiprosthesis. Conclusion: There is a significant discrepancy between previous expert recommendations and the actual activity levels that may be achieved after the implantation of a joint prosthesis. Future studies have to define the sports level, the type of sports and the type of prosthesis that provide a positive benefit-risk ratio using state-of-the-art low-abrasion bearing surfaces and prosthesis designs.

The Etiology of Improved Outcomes at High Volume Centers Learning Theory and the Case of Implant Flashing.

Increased volume has been shown to be associated with improved outcomes for many orthopaedic procedures. For individual surgeons, the concepts of learning curves and volume effects have been well established in the literature. For institutions, high-volume hospitals have also been shown to have better outcomes for orthopaedic procedures such as total joint replacements. However, exactly how hospital volume mediates this improvement is not well understood. Learning theory states that learning occurs as a result of accumulated experience, not based on time. We compared our institution's curve representing our implant flashing rates to other institutional data sets that exhibit learning and continuous quality improvement, including airline near misses, coal mining accidents, and others. Development of expertise is based on volume and rate of errors, and therefore higher volume is conducive to faster learning.

Shoulder Arthroplasty: Key Steps to Improve Outcomes and Minimize Complications.

Advances in shoulder replacement surgery have allowed for the successful treatment of various shoulder conditions. As the elderly population increases and the surgical indications for shoulder replacement surgery continue to expand, the number of shoulder replacements performed annually will continue to increase. Accordingly, the number of complications also will be expected to increase. Successful shoulder replacement outcomes require surgeons to have a thorough understanding of the surgical indications, surgical technique, and potential complications of the procedure. By reviewing the key aspects of shoulder replacement surgery and focusing on the surgical technique and common complications for both anatomic and reverse total shoulder arthroplasty, surgeons can help improve outcomes and minimize complications.

Update on Biomaterials.

Biomaterials are essential to the use and development of successful treatments for orthopaedic patients. Orthopaedic surgeons need to understand the expected clinical performance and the effects of implants in patients. Recent attempts to improve implant durability have resulted in adverse effects related to biomaterials and their relationship to patients. Examples of these adverse effects in hip arthroplasty include wear and corrosion of metal-on-metal bearings, trunnions, and tapered modular neck junctions. Conversely, polymers and ceramics have shown substantial improvements in durability. Improved implant compositions and manufacturing processes have resulted in ceramic head and acetabular liners with improved material properties and the avoidance of voids, which have, in the past, caused catastrophic fractures. Cross-linking of polyethylene with radiation and doping with antioxidants has substantially increased implant durability and is increasingly being used in joint prostheses other than the hip. Additive manufacturing is potentially a transformative process; it can lead to custom and patient-specific implants and to improvements in material properties, which can be optimized to achieve desired bone responses. Orthopaedic surgeons must understand the material properties and the biologic effects of new or altered biomaterials and manufacturing processes before use. In addition, a clear benefit to the patient must be proven based on superior preclinical results and high-quality clinical investigations before orthopaedic surgeons use new or altered biomaterials.

Total Arthroplasty of the Metatarsophalangeal Joint of the Hallux.

BACKGROUND: The current gold standard in the treatment of severe hallux rigidus is arthrodesis of the first metatarsophalangeal (MTP-I) joint. We present the results of a new 3-component MTP-I prosthesis. We determined (1) the intraoperative and perioperative complications; (2) survivorship of prosthesis components and rate of secondary surgeries for any reason; (3) prosthetic component stability and radiographic alignment; (4) the degree of pain relief; and (5) the midterm functional outcomes including radiographic range of motion (ROM). METHODS: From 2008 to 2010, we prospectively included 29 MTP-I prostheses in 25 patients. The average age of the patients was 63.1 years (range, 48-87 years). The average follow-up was 49.5 months (range, 36-62 months). We observed complications and reoperations. A visual analog scale for pain and the American Orthopaedic Foot & Ankle Society (AOFAS) forefoot score were obtained pre- and postoperation. Component stability and alignment were assessed using weight-bearing radiographs. Fluoroscopy was used to determine radiographic MTP-I ROM. RESULTS: Seven (24.1%) patients underwent 1 or more secondary surgeries. Four cases (13.7%) eventually had a conversion to MTP-I arthrodesis. Two patients (3 cases) died from causes not related to the procedure. This left 22 feet in 19 patients for final follow-up. All but 3 remaining prostheses showed stable osteointegration and no migration, but MTP-I alignment showed high variability. The average pain score decreased from 5.9 (range, 3-9) to 1.2 (range, 0-5). The average AOFAS forefoot score increased from 55 (range, 0-80) to 83.5 (range, 58-95). Range of motion initially increased from 37.8 degrees (range, 0-60 degrees) to 88.6 degrees (range, 45-125 degrees) intraoperatively and decreased to 29.0 degrees (range, 11-52 degrees) at latest follow-up. CONCLUSION: Our data suggest that total arthroplasty of MTP-I leads to a high amount of revision surgeries, but the remaining patients had significant pain relief at midterm follow-up. However, we observed high variability regarding the prosthesis component alignment and poor range of motion. LEVEL OF EVIDENCE: Level IV, prospective cohort study.

Are there differences between stemless and conventional stemmed shoulder prostheses in the treatment of glenohumeral osteoarthritis?

BACKGROUND: Conventional stemmed anatomical shoulder prostheses are widely used in the treatment of glenohumeral osteoarthritis. The stemless shoulder prosthesis, in contrast, is a new concept, and fewer outcome studies are available. Therefore, the purpose of the study was to investigate the early functional outcome and postoperative proprioception of a stemless prosthesis in comparison with a standard stemmed anatomic shoulder prosthesis. METHODS: Twelve patients (mean age 68.3 years [SD ± 5.4]; 5 female, 7 male) with primary glenohumeral osteoarthritis of the shoulder were enrolled, who underwent total shoulder arthroplasty (TSA) with a stemless total shoulder prosthesis, Total Evolution Shoulder System (TESS; Biomed, France). The control group consisted of twelve (age and gender matched) patients (mean age 67.8 years; [SD ± 7.1]; 9 female, 3 male), getting a TSA with a standard anatomic stemmed prosthesis, Aequalis Shoulder (Tournier, Lyon, France). Patients were examined the day before and six months after surgery. The pre- and postoperative Constant Score (CS) was evaluated and proprioception was measured in a 3D video motion analysis study using an active angle-reproduction (AAR) test. RESULTS: Comparing the postoperative CS, there was no significant difference between the groups treated with the TESS prosthesis (48.0 ± 13.8 points) and the Aequalis prosthesis (49.3 ± 8.6 points; p = 0.792). There was no significant difference in postoperative proprioception between the TESS group (7.2° [SD ± 2.8]) and the Aequalis group(8.7° [SD ± 2.7]; p = 0.196), either. Comparison of in the results of CS and AAR test pre- and postoperatively showed no significant differences between the groups. DISCUSSION: In patients with glenohumeral osteoarthritis, treated with TSA, the functional and the proprioceptive outcome is comparable between a stemless and a standard stemmed anatomic shoulder prosthesis at early followup. CONCLUSION: Further follow-up is necessary regarding the long-term performance of this prosthesis. TRIAL REGISTRATION: Current Controlled Trials DRKS 00007528 . Registered 17 November 2014.

[S3 Guideline. Part 3: Non-Traumatic Avascular Necrosis in Adults - Surgical Treatment of Atraumatic Avascular Femoral Head Necrosis in Adults]. / S3-Leitlinie. Teil 3: Atraumatische Femurkopfnekrose des Erwachsenen - Operative Therapie der atraumatischen Femurkopfnekrose des Erwachsenen.

The present article describes the guidelines for the surgical treatment of atraumatic avascular necrosis (aFKN). These include joint preserving and joint replacement procedures. As part of the targeted literature, 43 publications were included and evaluated to assess the surgical treatment. According to the GRADE and SIGN criteria level of evidence (LoE), grade of recommendation (EC) and expert consensus (EK) were listed for each statement and question. The analysed studies have shown that up to ARCO stage III, joint-preserving surgery can be performed. A particular joint-preserving surgery currently cannot be recommended as preferred method. The selection of the method depends on the extent of necrosis. Core decompression performed in stage ARCO I (reversible early stage) or stage ARCO II (irreversible early stage) with medial or central necrosis with an area of less than 30 % of the femoral head shows better results than conservative therapy. In ARCO stage III with infraction of the femoral head, the core decompression can be used for a short-term pain relief. For ARCO stage IIIC or stage IV core decompression should not be performed. In these cases, the indication for implantation of a total hip replacement should be checked. Additional therapeutic procedures (e.g., osteotomies) and innovative treatment options (advanced core decompression, autologous bone marrow, bone grafting, etc.) can be discussed in the individual case. In elective hip replacement complications and revision rates have been clearly declining for decades. In the case of an underlying aFKN, however, previous joint-preserving surgery (osteotomies and grafts in particular) can complicate the implantation of a THA significantly. However, the implant life seems to be dependent on the aetiology. Higher revision rates for avascular necrosis are particularly expected in sickle cell disease, Gaucher disease, or kidney transplantation patients. Furthermore, the relatively young age of the patient with avascular necrosis should be seen as the main risk factor for higher revision rate. The results after resurfacing (today with known restricted indications) and cemented as well as cementless THA in aFKN are comparable for the appropriate indication to those in coxarthrosis or other diagnoses. Regardless of the underlying disease endoprosthetic treatment in aFKN leads to good results. Both cemented and cementless fixation techniques can be recommended.

Rescate articular con colgajo anterolateral del muslo / Joint rescue with anterolateral thigh flap

La preservación del nivel de amputación tanto de la extremidad superior como de la inferior, puede mejorar la función residual y el proceso de rehabilitación protésica de la misma. Ambas van a estar condicionadas por la longitud restante de la extremidad, la presencia o no de articulaciones operativas y la calidad de la cobertura del muñón. Presentamos 2 casos de amputaciones. El primero es un caso agudo de amputación traumática de extremidad superior a la altura del tercio proximal de antebrazo, que asocia avulsión cutánea circular desde el tercio medio del brazo y con articulación de codo conservada. El segundo, es la secuela de una amputación infracondílea de extremidad inferior por osteosarcoma que presenta fístulas cutáneas con drenaje supurativo por osteomielitis en el muñón tibial. En ambos pacientes realizamos cobertura con colgajo anterolateral de muslo anastomosado a la arteria radial en el caso de la extremidad superior, y a la arteria genicular descendente en la extremidad inferior. En los dos casos el postoperatorio transcurrió sin complicaciones, logrando preservar las articulaciones del codo y de la rodilla respectivamente, así como la posterior rehabilitación protésica. Consideramos que el colgajo anterolateral del muslo permite aportar tejido de buena calidad como cobertura del muñón de amputación. Dadas las características del tejido aportado y su volumen, es idóneo tanto para cobertura de defectos agudos como de déficits de almohadillado en casos crónicos (AU)

Sometimes, the severity of the trauma or the existence of a cancer force to amputate a limb. The prosthetic rehabilitation process and residual function will be influenced by the remaining length of the limb, the presence or absence of functional joints and the quality of the coverage of the stump. Two cases of amputations are shown. The former is an acute traumatic upper limb amputation at the level of the proximal third of forearm with skin avulsion from the middle third of the arm and the elbow joint preserved. The second case is the sequelae of an amputation below the knee due to lower extremity osteosarcoma, which was referred with suppurative draining cutaneous fistulas as a consequence of an osteomyelitis of the femur in the stump. In both patients the stumps were covered with anterolateral thigh flap anastomosed over the radial artery in the case of the upper extremity, and over the descending genicular artery in the lower extremity. In both cases the postoperative course was uneventful, preserving the elbow and knee respectively and allowing the subsequent prosthetic rehabilitation. We consider that anterolateral thigh flap is a suitable option for the treatment of the amputation stump. Given the characteristics of the tissue and volume provided by this flap, it is appropriate for coverage of acute defects and for padding deficits in chronic cases (AU)