Characterization of primary chondrocytes harvested from hips with femoroacetabular impingement.

OBJECTIVE: Acetabular chondral lesions are common in patients with femoroacetabular impingement (FAI) syndrome. The aim of this study was (1) to evaluate the proliferation potential of primary human chondrocytes (hC) derived from both acetabular and femoral site and (2) to validate cellular differentiation during three-dimensional (3D) cultivation as a prerequisite for autologous matrix-assisted cartilage regeneration of the hip joint. METHODS: hC were isolated from cartilage samples obtained from N = 6 patients during offset reconstruction. Proteoglycan content was assessed by Safranin-O staining. Proliferation and cell viability were quantified by microscopic cell counting and Trypan Blue exclusion. Messenger ribonucleic acid (mRNA) expression levels of collagen type 1 and 2, aggrecan (ACAN), and interleukin-1ß (IL-1ß) genes were assessed upon monolayer cultivation, after 48 h/4-10°C - transport simulation and after 14 days of 3D hydrogel cultivation. RESULTS: Primary hC from acetabular and femoral damaged sites were viable. No significant intergroup differences were observed concerning cell viability (>95%) after monolayer cultivation and transport simulation. Harvest yields from acetabular and femoral cartilage samples were comparable to that known from knee joints (mean ± standard deviation (SD), 13.4 × 10(6) ± 5 × 10(6) cells per culture vs 20 × 10(6) cells). Redifferentiation was induced during 3D hydrogel cultivation as observed by increased levels of collagen II (1000-fold) and ACAN (10-fold) gene vs monolayer cultivation (P < 0.001). CONCLUSION: hC derived from damaged acetabular and femoral site are qualified for autologous matrix-assisted cartilage transplantation paving the way for cell-based cartilage regeneration in FAI patients.

[Total hip arthroplasty in overweight osteoarthritis patients]. / Die endoprothetische Versorgung beim übergewichtigen Koxarthrosepatienten.

BACKGROUND: An increasing number of patients scheduled for total hip arthroplasty (THA) are obese and exhibit a different risk profile from that of patients of normal weight. OBJECTIVES: To provide an overview of the impact of obesity on the outcome of primary THA. MATERIALS AND METHODS: Literature review and discussion of own epidemiological data. RESULTS: Obese patients can expect as much functional improvement as non-obese patients after THA. However, peri- and postoperative complication (e.g., periprosthetic infection and dislocation) rates are reported to be increased in obese THA patients. CONCLUSIONS: The knowledge of obesity-associated risks is the prerequiste for successful THA in obese patients.

[Arthroplasty for osteoarthritis secondary to hip dysplasia: Problem-oriented treatment strategies]. / Endoprothese bei Dysplasiecoxarthrose: Problemorientierte Versorgungsstrategien.

BACKGROUND: Because of anatomical variations total hip arthroplasty (THA) can be demanding in patients with osteoarthritis secondary to hip dysplasia. OBJECTIVES: Depending on the degree of bony deformation, hip dislocation and soft tissue alteration numerous treatment strategies are available. This review describes current approaches that address frequent deformities. MATERIALS AND METHODS: Review of relevant clinical studies, meta-analyses, and presentation of our own approach. RESULTS: Pre-operative planning (based on a thorough clinical and radiographic examination) is essential. Acetabular reconstruction close to the primary acetabulum should always be intended. Roof augmentation and/or cup medialization can support stable bony implant fixation. Subtrochanteric shortening osteotomy of the femur is a demanding but reliable technique that avoids nerve damage in cases where inappropriate lengthening would be necessary (i.e., high riding dislocation). CONCLUSIONS: Although the post-operative complication rate is elevated after THA for dysplastic hips compared with primary osteoarthritis, the overall functional results and implant survival are comparable.

Prevalence of low back pain in adolescent athletes - an epidemiological investigation.

Low back pain (LBP) is a common symptom in the populations of western countries, and adolescent athletes seem to be prone to LBP. The main objective of this study was to analyze the point (LBP within the last 48 h), 1-year (LBP within the last 12 months) and lifetime (LBP within the entire life) prevalence rates of LBP in adolescent athletes participating in various sports. We also assessed the characteristics of LBP and its association with potential risk factors. To this end, 272 competitive adolescent athletes involved in 31 different sports (158 males, 113 females, 15.4 ± 2.0 years, body mass index [BMI] 20.3 ± 2.4 kg/m(2)) were enrolled in a 10-month prospective clinical trial that included a questionnaire and physical examination. We found a point prevalence of 14%, a 1-year prevalence of 57%, and a lifetime prevalence of 66% for LBP. The mean age of first appearance of LBP was 13.1 ± 2.0 years. The lifetime prevalence was significantly higher in volleyball than in biathletes (74.3 vs. 45.7%, p = 0.015). Our findings confirm that LBP is a common symptom in adolescent athletes; LBP prevalence correlates with sports participation and individual competitive level. Adolescent athletes with LBP should receive a thorough diagnostic work-up and adapt training and technique correspondingly when indicated.

[Complications of metal-on-metal tribological pairing]. / Komplikationen bei Metall-Metall-Gleitpaarungen.

BACKGROUND: Metal-on-metal (MoM) tribological pairing results in less volumetric abrasion than pairing with the conventionally used polyethylene and is associated with a lower risk of material failure compared to other hard-hard pairings. An increased frequency of problem cases in recent years has led to a great increase in uncertainty. Against this background in this article the current aspects of epidemiology, etiology, diagnostics and treatment of complications in MoM hip joint endoprostheses will be discussed. EPIDEMIOLOGY AND ETIOLOGY: Based on the results from national endoprosthesis registers and selected clinical studies an evaluation of the rate of local complications from MoM tribological pairings was undertaken. A differentiation was made between MoM pairings in pedicled small head prostheses (≤ 32 mm), large head (> 32 mm) and surface replacement (OFE) endoprostheses. Each year MoM endoprostheses release on average 10(12)-10(14) cobalt (Co) and chromium (Cr) nanoparticles per patient. This release of metal ions and particles can lead to a variety of tissue reactions. DIAGNOSTICS: A differentiation must be made between regular routine diagnostics within the framework of implant follow-up screening and specific investigations due to the occurrence of complaints. The diagnostics for patients treated with MoM hip endoprostheses consists of a standardized step-wise approach considering possible differential diagnoses and the utilization of modern laboratory chemical and radiological methods. When problems occur, a differentiation should preferentially be made between complaints not caused by metal and mechanical problems (e.g. prosthesis loosening and impingement) and symptoms due to periprosthetic infections. THERAPY OF COMPLICATIONS: The normal standards for hip endoprosthetics are also valid for periprosthetic infections, fractures and other general complications. Specific measures are, however, necessary for complications due to metal-specific risks.

[Update on metal-on-metal hip joints]. / Update Metall-Metall-Gleitpaarungen.

Increasing data are available describing risk factors for the development of local and systemic adverse events following operations using metal-on-metal (MoM) hip implants. The prevalence and clinical relevance of metal-associated problems are, however, still under debate. They can be influenced by type and position of implant as well as patient-specific factors. Patients with small MoM heads (maximum diameter 32 mm) and subgroups of resurfacing arthroplasty can achieve good long-term survival. The use of large head MoM implants (diameters greater than 36 mm), however, is currently not advised due to the unsatisfactory results.

[Academic clinical medicine in orthopedic and trauma surgery: which route will the next generation choose?]. / Akademische klinische Medizin in Orthopädie und Unfallchirurgie: Welchen Weg geht der Nachwuchs?

BACKGROUND: An increasing clinical pressure forces academic surgeons in Germany to decide between private life and research activities. How do those people decide and how do they develop their individual career plan? MATERIAL AND METHODS: In an e-mail survey German orthopedic and trauma surgeons were interviewed on their way of reconciliation of private life, clinical duties and research. The survey included the same questions as the previous survey and a follow-up of 66 % was achieved. RESULTS: The number of consultants in the questioned cohort increased from 44 % to 66 %. More than 80 % reported that the workload had increased which was accompanied by a more clinical orientation of research activities. When asked about personal priorities and wishes leisure time was ranked first, surgical skills, research and income followed in that order. The majority were content with the current situation and career path. CONCLUSIONS: This is the first study on occupational conditions in orthopedic and trauma surgeons in a time-line based manner. It became evident that a more clinical orientation of research is needed to match the interests of clinically engaged surgeons in orthopedics and traumatology.

Expression pattern differences between osteoarthritic chondrocytes and mesenchymal stem cells during chondrogenic differentiation.

OBJECTIVE: The use of mesenchymal stem cells (MSCs) for cartilage regeneration is hampered by lack of knowledge about the underlying molecular differences between chondrogenically stimulated chondrocytes and MSCs. The aim of this study was to evaluate differences in phenotype and gene expression between primary human chondrocytes and MSCs during chondrogenic differentiation in three-dimensional (3D) pellet culture (PC). MATERIALS AND METHODS: Chondrocytes isolated from cartilage samples obtained during total knee alloarthroplastic procedure (N=8) and MSCs, purified from bone marrow aspirates of healthy donors (N=8), were cultivated in PC under chondrogenic conditions. Immunohistology and quantitative reverse transcribing PCR (RT-PCR) were performed for chondrogenic-specific markers (i.e., Sox9, Collagen II). Global gene expression of the so-cultivated chondrocytes and MSCs was assessed by a novel approach of microarray-based pathway analysis. Refinement of data was done by hypothesis-driven gene expression omnibus (GEO) dataset comparison. Validation was performed with separate samples in transforming growth factor (TGF)ß+ or TGFß- conditions by use of quantitative real-time RT-PCR. RESULTS/CONCLUSIONS: Chondrogenic commitment of both cell types was observed. Interestingly, chondrocytes demonstrated an upregulated fatty acid/cholesterol metabolism which may give hints for future optimization of culture conditions. The novel microarray-based pathway analysis applied in this study seems suitable for the evaluation of whole-genome based array datasets in case when hypotheses can be backed with already existing GEO datasets. Future experiments should further explore the different metabolic behaviour of chondrocytes and MSC.

[Durom™ hip resurfacing. Short- to midterm clinical and radiological outcome]. / Durom™-Hüftoberflächenersatz. Kurz- bis mittelfristiges radiologisches und klinisches Ergebnisse.

BACKGROUND: Modern hip resurfacing as an alternative for stemmed total hip replacement therapy is associated with a specific risk profile. The aim of this study was therefore to assess the short- to midterm clinical and radiological outcome after introduction of the Durom™ Hip Resurfacing prosthesis in a consecutive series. MATERIALS AND METHODS: A total of 132 hips (119 patients, 34 female, mean age 48±8,3 years) were evaluated functionally (Harris Hip Score, UCLA and Tegner activity scores) and radiologically with a mean follow-up period of 29 (6-60) months. Furthermore, preoperative ASA- and Charnley-scores, perioperative parameters as well as complications were registered. RESULTS: During the observation period the Harris Hip Score improved by a mean of 36.6 points to 92.5±11.6 points (p<0.01). ULCA and Tegner scores improved by a mean of 3.1 and 1.6 to 7.1 and 4.0 points, respectively. Three patients (2.3%) needed revision surgery due to periprosthetic fracture, prosthesis infection, and aseptic loosening of the femoral component. In four patients (3.1%) an initial migration of the acetabular component not requiring surgical revision was observed radiologically. CONCLUSION: The Durom™ Hip Resurfacing prosthesis demonstrated a low revision rate and a good mid-term functional and radiological outcome. Due to acetabular cup migrations in a small number of patients we now use an implant with modified surface design.

Mimicry of surgical site infection - Case report.

BACKGROUND CONTEXT: Calciphylaxis is a rare complication of secondary hyperparathyroidism caused by calcifications of small blood vessels in the skin and soft tissue. The disease occurs almost exclusively in patients with chronic kidney disease and has an incidence of approximately 50 cases per year in Germany [1]. PURPOSE: We present a case of a 61-year-old woman with calciphylaxis in connection with a primary knee endoprosthesis implantation. STUDY DESIGN: Case report. METHODS: A review of the medical records since the time of initial hospital admission throughout the entire hospitalization until the death of the patient was performed. RESULTS: Calciphylaxis caused severe soft tissue complications after total joint arthroplasty. Despite interdisciplinary therapy, including revision and plastic surgery as well as intensive care, the patient died 4 months after primary total knee arthroplasty due to septic multi-organ failure. CONCLUSION: Calciphylaxis may cause severe soft tissue complications after total joint arthroplasty and should be considered as potential differential diagnosis to surgical site infection. This is the first case report on calciphylaxis as direct complication of total joint replacement surgery.

[Bone tissue engineering in clinical application : assessment of the current situation]. / Knochen-Tissue-Engineering in der klinischen Anwendung : Eine Standortbestimmung.

Treatment of severe bone defects remains a challenge in orthopaedic surgery and traumatology. Surgical techniques should provide primary stability to reach osseous integration and secondary remodeling of bone grafts and substitute materials. None of the currently available substitute materials provides osteoconduction and osteogenesis comparable to those of human allografts and autografts. To enhance osteoinductive and osteogenetic properties of these implants mesenchymal stem cells are used successfully in bone tissue engineering approaches. The aim of this report is to summarize the currently available data on bone tissue engineering and preliminary experience with a tissue engineered graft in acetabular revision surgery after loosening of a hip replacement.

Cytotoxicity of drugs injected into joints in orthopaedics.

OBJECTIVES: Intra-articular injections of local anaesthetics (LA), glucocorticoids (GC), or hyaluronic acid (HA) are used to treat osteoarthritis (OA). Contrast agents (CA) are needed to prove successful intra-articular injection or aspiration, or to visualize articular structures dynamically during fluoroscopy. Tranexamic acid (TA) is used to control haemostasis and prevent excessive intra-articular bleeding. Despite their common usage, little is known about the cytotoxicity of common drugs injected into joints. Thus, the aim of our study was to investigate the effects of LA, GC, HA, CA, and TA on the viability of primary human chondrocytes and tenocytes in vitro. METHODS: Human chondrocytes and tenocytes were cultured in a medium with three different drug dilutions (1:2; 1:10; 1:100). The following drugs were used to investigate cytotoxicity: lidocaine hydrochloride 1%; bupivacaine 0.5%; triamcinolone acetonide; dexamethasone 21-palmitate; TA; iodine contrast media; HA; and distilled water. Normal saline served as a control. After an incubation period of 24 hours, cell numbers and morphology were assessed. RESULTS: Using LA or GC, especially triamcinolone acetonide, a dilution of 1:100 resulted in only a moderate reduction of viability, while a dilution of 1:10 showed significantly fewer cell counts. TA and CA reduced viability significantly at a dilution of 1:2. Higher dilutions did not affect viability. Notably, HA showed no effects of cytotoxicity in all drug dilutions. CONCLUSION: The toxicity of common intra-articular injectable drugs, assessed by cell viability, is mainly dependent on the dilution of the drug being tested. LA are particularly toxic, whereas HA did not affect cell viability.Cite this article: P. Busse, C. Vater, M. Stiehler, J. Nowotny, P. Kasten, H. Bretschneider, S. B. Goodman, M. Gelinsky, S. Zwingenberger. Cytotoxicity of drugs injected into joints in orthopaedics. Bone Joint Res 2019;8:41-48. DOI: 10.1302/2046-3758.82.BJR-2018-0099.R1.

Cholecystokinin-B/gastrin receptor binding peptides: preclinical development and evaluation of their diagnostic and therapeutic potential.

The high sensitivity of pentagastrin stimulation in detecting primary or metastatic medullary thyroid cancer (MTC) suggests widespread expression of the corresponding receptor type on human MTC. Indeed, autoradiographic studies demonstrated cholecystokinin (CCK)-B/gastrin receptors not only in >90% of MTCs but in a high percentage of small cell lung cancers and potentially a variety of gastrointestinal adenocarcinomas. In a pilot study, we have demonstrated the feasibility of radiolabeled gastrin-I to target CCK-B receptor-expressing tissues in vivo in animals and patients (T. M. Behr et al., Eur. J. Nucl. Med., 25: 424-430, 1998). The aim of the present study was to systematically optimize, in a preclinical model, suitable radioligands for targeting CCK-B receptors in vivo. For this purpose, a variety of CCK/gastrin-related peptides, all having in common the COOH-terminal CCK-receptor binding tetrapeptide sequence Trp-Met-Asp-PheNH2 or derivatives thereof, were studied. They were radioiodinated by the Iodogen or Bolton-Hunter procedures. The peptides tested were members of the gastrin- or cholecystokinin families or possessed characteristics of both, which differ by the intramolecular position of a tyrosyl moiety (occurring in native or sulfated form). Their stability and affinity were studied in vitro and in vivo; their biodistribution and therapeutic efficacy were tested in nude mice bearing s.c. human MTC xenografts. Diethylene-triamine-pentaacetate derivatives of suitable peptides were synthesized, evaluated, and labeled with (111)In. All members of the CCK or gastrin family were stable in serum (with t(1/2)s of several hours at 37 degrees C); nevertheless, the stability of those peptides was highest that bore the NH2-terminal pGlu residues (e.g., big gastrin, gastrin-I, caerulein, and others) or D-amino acids. In accordance to their comparably low affinity, nonsulfated members of the CCK family showed fairly low uptake in the tumor and other CCK-B receptor-expressing tissues (e.g., the stomach). Sulfated CCK derivatives performed significantly better but additionally displayed a high uptake in normal, CCK-A receptor-expressing tissues (such as the liver/gallbladder, pancreas, and bowel). Best tumor uptake and tumor:nontumor ratios were obtained with members of the gastrin family, probably because of their selectivity and affinity for the CCK-B receptor subtype. Pilot therapy experiments in MTC bearing animals showed significant antitumor efficacy as compared with untreated controls. (111)In-Labeled diethylene-triamine-pentaacetate derivatives of minigastrin showed excellent targeting of CCK-B receptor-expressing tissues in animals and a normal human volunteer. These data suggest that CCK/gastrin analogues may be a useful new class of receptor binding peptides for diagnosis and therapy of CCK-B receptor-expressing tumors, such as MTC or small cell lung cancer. Nonsulfated gastrin derivatives may be preferable because of their CCK-B receptor selectivity, and hence, lower accretion in normal CCK-A receptor-expressing organs. Further preclinical as well as clinical studies are ongoing.

AIDS- und Hepatitisprävention im sächsischen Justizvollzug Risikosituation und Schutzmöglichkeiten : Risikosituation und Schutzmöglichkeiten.

In Saxon prisons the risk of infection by HIV or hepatitis viruses differs from those in the Western German federal states in certain aspects. Particularly the intravenous use of drugs plays a minor role. Nevertheless there are other risks of transmission, and the general consumption of (non-injectable) drugs is estimated to be very high. Therefore a need exists for adequate and suitable measures of prevention, taking into account the specific situation in Saxon prisons. Supposedly the chances to structurally counteract the development of the same intravenous drug use habits as in Western Germany are low.

Periacetabular bone metabolism following hip revision surgery. PET-based evaluation of allograft osteointegration.

UNLABELLED: The treatment of loosened total hip replacement (THR) acetabular components may require the management of severe bone defects. Although being applied for decades, there is only limited scientific data about the osteointegration of cancellous bone allografts (CBA) and other void fillers. Monitoring of periprosthetic bone regeneration could possibly help to optimize this process thereby reducing late failure rates. The aim of this study was to show osteometabolic changes in periprosthetic CBA after THR revision with the use of sodium-[18F]-fluoride (NaF) and positron emission tomography (PET). PATIENTS, METHODS: Twelve patients undergoing THR revision with the use of CBA were prospectively enrolled in the study. Nine patients completed all necessary examinations and were included in the evaluation. The temporal pattern of osteointegration was assessed via NaF-PET at one (PET1) and six weeks (PET2) after surgery. CBA, tantalum implants, supraacetabular regions ipsilateral and contralateral, and parasymphyseal pubic bones were delineated as volumes of interest (VOI) in postop CT scans, which were then merged with the PET data. RESULTS: In comparison to the contralateral supraacetabular reference bone, a significant 1.5-fold increase of osteometabolic activity from PET1 to PET2 was seen in the CBA region. Also, the ipsilateral supraacetabular host bone showed a higher NaF-influx in week 6, compared to the first postoperative week. The supraacetabular site exhibited a significantly 1.8- to 2-fold higher influx and uptake than bone regions in non-operated sites. Tantalum implants had a low NaF influx at both time points investigated. CONCLUSION: Using NaF-PET osteometabolic changes of CBA and implant-bone-interfaces can be monitored. Applying this method we demonstrated early periprosthetic temporal bone regeneration patterns in THR cup revision patients.

[Survey of the simultaneous management of clinical and research burdens in German University orthopaedic and trauma departments]. / Ergebnisse einer Befragung zur Vereinbarkeit von klinischer und akademischer Entwicklung an orthopädischen und unfallchirurgischen Universitätskliniken in Deutschland.

AIM: Academic careers often place the burden of research on top of clinical work. This conflict denotes a demanding task especially in surgical disciplines, such as orthopaedics and traumatology. Driven by changes in the social system, concerning, e.g., leisure and parentship, the future organisation of the academic workplace needs to address these individual issues. With the aim to evaluate individual motivation towards combining research, clinical work and private life and to receive suggestions for improvement we conducted a survey addressing residents employed in the orthopaedic and traumatological departments of German university hospitals. METHOD: With the support of the "Junges Forum der Deutschen Gesellschaft für Orthopädie und Unfallchirurgie (DGOU)", a survey, containing 21 questions about occupational and private issues, was sent out to the orthopaedic and traumatologic departments of 25 university hospitals in Germany. The focus of the questions was set on motivation, priorities and personal resources. It was possible to answer the questions by e-mail; later an anonymous online version of the survey was set in action as well. RESULTS: Completely answered forms were received from n = 105 physicians, of which 88 % were judged as active researchers. Over 50 % of the participants were satisfied with their clinical career and with their research results. 96 % of the survey participants felt sure that most of the research could only be managed during spare time. A majority of the participants supported the idea of receiving leave of absence from clinical duties for research in order to serialise the scientific and clinical careers. Interestingly, when focusing on priority settings, salary aspects were ranked as low as research interests, falling behind the wish for a more intensive surgical training and more leisure time. CONCLUSIONS: Individual solutions seem to be necessary to achieve a scheduled efficiency of clinical and research careers. This includes structural developments (like a professionally headed lab) and the establishment of dynamic clinical structures. It seems possible that the clinical organisation of physicians in teams might offer solutions to cope with the demands of surgical training and clinical care on the one hand and research on the other hand.

[Revision surgery of hip resurfacing]. / Revisionschirurgie des Oberflächenersatzes.

Early results of contemporary hip resurfacing are encouraging and consequently an increasing number of this procedure has been performed worldwide. A theoretical advantage of hip resurfacing is that failed components can be revised safely and successfully revised to a conventional total hip arthroplasty. As the number of systematically analyzed failures is still limited, however, current data from the literature cannot substantially support this assumption. Our personal results indicate that the conversion of a failed femoral cup (i.e., due to neck fracture or aseptic loosening) to a conventional stem is a relatively simple and safe procedure. If and how potential wear of a firmly integrated acetabular component might have any impact on this type of revision, warrants further investigations. The conversion of acetabular components is influenced by the quality of the remaining pelvic bone stock and can therefore be compared to conventional revision surgery. However, as most providers of hip resurfacings systems only offer one-piece acetabular shells, the possibility of an isolated modular insert exchange is rare. In conclusion, the argument of easy revision surgery after hip resurfacing should be used with care.

Predictors of humeral head ischemia after intracapsular fracture of the proximal humerus.

The purpose of this study was to evaluate predictors of fracture-induced humeral head ischemia. Between February 1998 and December 2001, 100 intracapsular fractures of the proximal humerus, treated by open surgery, were included in a prospective surgical evaluation protocol (mean age, 60 years; minimum, 21 years; maximum, 88 years; 45 men; 57 right shoulders). Fracture morphology was assessed following a structured questionnaire and based on radiographic and intraoperative findings. Perfusion was assessed intraoperatively by observation of backflow after a borehole was drilled into the central part of the head in all shoulders and by intraosseous laser Doppler flowmetry in 46. Good predictors of ischemia were the length of the metaphyseal head extension (accuracy, 0.84 for calcar segments <8 mm), the integrity of the medial hinge (accuracy, 0.79 for disrupted hinge), and the basic fracture pattern (accuracy, 0.7 for combined types 2, 9, 10, 11, and 12). Moderate and poor predictors of ischemia were fractures consisting of four fragments (accuracy, 0.67), angular displacement of the head (accuracy, 0.62 for angulations over 45 degrees ), the amount of displacement of the tuberosities (accuracy, 0.61 for displacement over 10 mm), glenohumeral dislocation (accuracy, 0.49), head-split components (accuracy, 0.49), and fractures consisting of three fragments (accuracy, 0.38). When the above criteria (anatomic neck, short calcar, disrupted hinge) were combined, positive predictive values of up to 97% could be obtained. The most relevant predictors of ischemia were the length of the dorsomedial metaphyseal extension, the integrity of the medial hinge, and the basic fracture type determined with the binary description system.