Articular Injury Research Articles

The Tibial Pilon Fractures: Are there Problems?

decade [2]. These fractures may be caused by falls, road accidents or sport injuries. TPF may be produced by two different dynamics: shear-stress injuries, which separate bone fragments, and compression injuries, which compress and impact bony matter. The mechanism is the implosion of the tibial plafond caused by axial compression between the talus and the distal tibial articular surface, with or without horizontal torsion [3]. It is often associated with significant degloving of the soft tissue surrounding the bone, while the skin, capsule and ligaments are partly spared. The aim of operative treatment is to anatomically reduce the fracture fragments to restore the congruity of the joint surface and promote bony union with minimal disruption of the soft tissue envelope [4]. So the TPF are always complex. Its complexity is related to the number of bone fragments, the decomposition of the bone fragments and the lesion of the neighboring soft tissues. Muller’s AO classification is the more complete and universally accepted system: it characterizes Type A (not articular), type B (partially articular) and type C (completely articular) fractures. TPF can also be classified by Ruedi and Allgower classification that includes three type of fracture depending on the displacement of articular surface, metaphyseal and injury extent of fractures [5]. The treatment of this type of fractures is a very timely topic, since there is no real consensus on the unique methods of treatment, which must take into account not only the stabilization of bone but also soft tissue which frequently leads to complications. Non operative management, such as cast immobilization, is reserved only for nondisplaced articular fractures, patients who have surgical controindications because of medical co-morbidities, or patients with low demand such as those who are nonambulatory. Surgical treatments are varied and different: minimally invasive osteosynthesis (MIO), open reduction and internal fixation (ORIF), minimally invasive plate osteosynthesis (MIPO), esternal fixation (EF), external fixator combined with limited invasive internal fixation (LIFEF), ilizarov treatment. Operative fixation of TPF has presented a significant challenge to the orthopaedic surgeon as the extensive soft tissue damage associated with such injuries makes surgical intervention hazardous. Advantages of minimally invasive osteosynthesis of pilon fractures compared to conventional open reduction and osteosynthesis, include protection of the soft tissue and no further disturbances of circulation-ideal prerequisites for undisturbed bone healing. Ruedi and Allogower [5] believed that anatomical restoration of the articular surface was fundamental surgical point. They considered essential: the restoration of the length and axis of fibula or tibia, the reconstruction of the distal end of the tibia, the filling of the defect resulting from im paction, using cancellous autografts, the support of the medial side of the tibia by plating to prevent a late varus deformity. White et al. say that provided surgery is performed expeditiously by experienced orthopedic trauma surgeons, most tibial pilon fractures can be stabilized by primary ORIF within a safe and effective operative window with relatively low rates of wound complications, a high quality of reduction, and functional outcomes that compare favorably with the published results for all other reported surgical treatments of these severe incurie [6]. A retrospective study by Watson et al. has shown that there is a significantly higher complication rate with the use of open plating techniques in AO type C fractures of the distal tibia, and this is probably related to the amount of dissection and stripping of soft tissues needed to achieve reduction and plate fixation [7].

Treatment of the Acetabular Fracture

Acetabular fractures resulting from a high-energy injury show variable forms according to each fracture mechanism, and are composed of complex anatomical structures. Plain radiographs accompanying threedimensional computer tomography is inevitable, because it is necessary to perform a multidirectional imaging analysis as a diagnosis. Conservative treatment, open reduction with internal fixation, percutaneous screw fixation, and primary artificial hip replacement can be performed. Despite the various treatment methods to the associated injuries, such as comminuted fracture, articular surface injury, poor bone quality and etc, are huge burden for the treatment. Further, there are varying complications, such as thromboembolism, post-traumatic osteoarthritis, avascular necrosis, infection, nerve palsy, heterotopic bone formation and etc. Therefore, physicians need to an accurate classification of fracture and be able to provide rehabilitation, as soon as possible, after rigid internal fixation via open anatomical articular reduction. also In addition, physicians must also pay great attention to prevent complications.

Proximal Tibial Intra-articular Osteotomy for Treatment of Complex Schatzker Type IV Tibial Plateau Fractures With Lateral Joint Line Impaction

This study presents a retrospective review of 8 patients with 9 cases of an uncommon variant of medial tibial plateau fracture treated with a surgical approach not previously described in the literature. The fracture pattern is characterized by a displaced medial tibial plateau fracture with significant central and posterior impaction of the lateral tibial articular surface but an intact lateral cortex. A novel surgical approach with an intra-articular osteotomy of the lateral tibial plateau was used to facilitate visualization, reduction, and instrumentation of the lateral articular injury. Early clinical and radiographic results of this treatment approach were reviewed. We describe the fracture pattern, surgical technique, and early results and propose this technique as a reasonable alternative for treatment of a challenging clinical entity.

Gastroprotective effect of mummy on induced gastric ulcer in rats

Mummy was used in traditional medicine as a remedy for inflammation, articular injuries, rheumatism, bone fractures, wounds and back pains. In previous research, the healing effects of mummy on a rabbit’s tibial fracture were studied, and the results supported its efficacy. In consideration of claims and suggestions by traditional medicine about the effectiveness of mummy on wound healing, the present study was aimed at investigating the protective effect of mummy on gastric ulcer induced by ethanol. Young male albino rats (NMRI strain, n = 21, 190–230 g body weight) were randomly divided into three experimental groups: treatment group, positive control group and negative control group, each containing seven rats. All animals had been exposed to starvation for 24 h and then received oral ethanol (1 ml/200 g body weight). The treatment group received 100 mg/kg/day mummy; the positive control group received 200 mg/kg/day cimethidine, and the negative control group received 5 ml/kg/day distilled water for 2 weeks by gavages. One hour after the last treatment, all animals were killed, and their stomachs were dissected. The number and length of ulcers were determined using stereomicroscope; then graticule and the ulcer index and curative ratio were calculated. Data was analysed using one-way ANOVA and Tukey’s post hoc test. The administration of mummy significantly decreased the gastric ulcer score and ulcer index in the treatment group, compared with the positive control and negative control groups. The curative ratio in the treatment group was significantly higher than the negative control and the positive control groups (89.26 versus 87.79 %, respectively). The results showed excellent effects of mummy on wound healing after the ethanol-induced gastric ulcer in rats.

Hip Arthroscopy and the Anterolateral Portal: Avoiding Labral Penetration and Femoral Articular Injuries

Establishing the introductory viewing portal is a key step in hip arthroscopy. Most hip arthroscopists initially gain access to the central compartment of the hip through the anterolateral portal. Iatrogenic injury to the labrum or the femoral head chondral surface is a common yet under-reported complication of the procedure. Instead of directing the needle toward the clear space of the distracted joint, labral penetration can be minimized by directing the needle slightly anteroinferior to the clear space, overlapping the superior femoral head. Femoral head scuffing can be minimized by adjusting the position of the beveled needle and confirming a straight guidewire trajectory before trocar placement. This technical note addresses surgical pearls to minimize iatrogenic injury during initial central compartment access.

Strategies in Articular Cartilage Restoration—Present Advances in Biologic Intervention for Adult Knee Problems

Although a number of new methods have improved our ability to treat articular injuries of the knee, no procedures have yet been proven to restore injured hyaline cartilage to its original state. Multiple techniques are used to address full-thickness chondral or osteochondral defects. This review briefly examines surgical options for this pathology. If amenable, all attempts should be made to repair osteochondral injuries. If unable to do so, preoperative anatomic factors, such as alignment, ligamentous stability, and meniscal integrity, should be carefully considered. Additionally, indications for surgery and patient factors must be thoroughly reviewed to identify appropriate candidates for treatment. Size and previous attempts at treatment often dictate care, which may include microfracture, osteochondral transplantation (osteoarticular transfer system and mosaicplasty), or autologous chondrocyte implantation. Upcoming advances intend to minimize surgical morbidity while improving cartilage regeneration and articular incorporation. Despite the new developments surrounding this field, much is still unknown, and novel treatments should be addressed with caution.

Arthroscopy of the fetlock joint of the dromedary camel

To describe a technique for arthroscopy of the fetlock joint of the dromedary camel, and the problems that could occur during and after arthroscopy. Seven animals (4 cadaveric limbs and 3 living camels) were used in this study. Two dorsal arthroscopic portals (lateral and medial) and one palmaro-lateral portal were used. Distension of the joint capsule was effected by injecting Ringer´s lactate solution into the joint cavity. Landmarks for the dorsal arthroscopic portals were located at the centre of the groove bounded by the lateral branch of the suspensory ligament and the large metacarpus at a point 1 cm proximal to the joint. The palmaro-lateral portal was located in a triangular area between the branch of the suspensory ligament, the large metacarpus, and the sesamoid bone, with insertion of the arthroscope in a 45° joint flexion angle. Arthroscopy of the fetlock joint via the dorso-lateral portal allowed examination of the distal end of the large metacarpus and the proximal end of the first phalanx of the fourth digit. Arthroscopy via a dorso-medial approach allowed examination of the distal end of the large metacarpus and the proximal end of the first phalanx and the distal end of the third digit. The palmaro-lateral portal allowed examination of the sesamoid bones, the synovial membrane, and the synovial villi. The main complications recorded during arthroscopy were iatrogenic articular surface injury as well as obstruction of vision with the synovial villi. This is the first work to describe the normal arthroscopy of the fetlock joint in the dromedary camel, the arthroscopic portals, and the complications that could occur during and after arthroscopy. Further studies are required for diagnosis of pathological changes in the fetlock joint of the dromedary camel and for arthroscopy of other joints in the dromedary camel.

Inhibitory Effect of Curcumol on Jak2-STAT Signal Pathway Molecules of Fibroblast-Like Synoviocytes in Patients with Rheumatoid Arthritis

Hyperplasia of synovial membrane in rheumatoid arthritis (RA) is a critical pathological foundation for inducing articular injury. The janus kinase and signal transducer and activator of transcription (Jak-STAT) pathway plays a critical role in synovial membrane proliferation induced by platelet-derived growth factor (PDGF). To explore the anti-cell proliferation mechanism of curcumol, a pure monomer extracted from Chinese medical plant zedoary rhizome, the changes of Jak2-STAT1/3 signal pathway-related molecules in synoviocytes were observed in vitro. In this study, the fibroblast-like synoviocytes (FLS) in patients with RA were collected and cultured. The following parameters were measured: cell proliferation (WST-1 assay), cell cycles (fluorescence-activated cell sorting, FACS), STAT1 and STAT3 activities (electrophoretic mobility shift assay, EMSA), and the protein expressions of phosphorylated Jak2, STAT1, and STAT3 (Western blot). It was shown that curcumol could inhibit the RA-FLS proliferation and DNA synthesis induced by PDGF-BB in a dose-dependent manner in vitro. The transcription factors activities of STAT1 and STAT3 were obviously elevated after PDGF-BB stimulation (P < 0.05). Super-shift experiments identified the STAT1 or STAT3 proteins in the complex. Furthermore, the different concentration curcumol could downregulate the DNA binding activities of STAT1 and STAT3 (P < 0.05) and inhibit the phosphorylation of Jak2 while it had no effect on the protein expressions of STAT1 and STAT3. Positive correlations were found between changes of cell proliferation and DNA-binding activities of STAT1 and STAT3, respectively (P < 0.01). In conclusion, curcumol might suppress the FLS proliferation and DNA synthesis induced by PDGF-BB through attenuating Jak2 phosphorylation, downregulating STAT1 and STAT3 DNA-binding activities, which could provide theoretical foundation for clinical treatment of RA.

Post‐traumatic osteoarthritis: Improved understanding and opportunities for early intervention

Even with current treatments of acute joint injuries, more than 40% of people who suffer significant ligament or meniscus tears, or articular surface injuries, will develop osteoarthritis (OA). Correspondingly, 12% or more of all patients with lower extremity OA have a history of joint injury. Recent research suggests that acute joint damage that occurs at the time of an injury initiates a sequence of events that can lead to progressive articular surface damage. New molecular interventions, combined with evolving surgical methods, aim to minimize or prevent progressive tissue damage triggered by joint injury. Seizing the potential for progress in the treatment of joint injuries to forestall OA will depend on advances in (1) quantitative methods of assessing the injury severity, including both structural damage and biologic responses, (2) understanding of the pathogenesis of post-traumatic OA, taking into account potential interactions among the different tissues and the role of post-traumatic incongruity and instability, and (3) application of engineering and molecular research to develop new methods of treating injured joints. This paper highlights recent advances in understanding of the structural damage and the acute biological response following joint injury, and it identifies important directions for future research.

Predictors of Late Clinical Outcome Following Orthopedic Injuries After Multiple Trauma

The long-term clinical status of surviving patients with multiple injuries has not been well described. The aim of this study was to evaluate whether certain injury patterns predispose a patient to a poor clinical outcome 10 or more years after multiple injuries. Patients who were treated at a level I trauma center at least 10 years before participation in this study were reinvited for a follow-up physical examination. Clinical outcome included the assessment of pain, gait, and various outcome scores (Short-Form [SF]-12, Lysholm, Merle D'Aubigne) were also used to measure outcome. Binary logistic regression was used to test predictors of physical and psychosocial outcomes 10 years or longer after trauma. Differences between the types of injury and outcomes were assessed using Mann-Whitney and Kruskal Wallis tests. Of 1,034, 637 patients (62%) participated in this study. Predictors of poor physical and psychosocial functioning using a clinical outcome score at 10 or more years follow-up included lower extremity amputation (odds ratio = 15.08; 95% confidence interval = 1.87-121.61) and a higher Abbreviated Injury Scale (AIS) spine score (SF-12 Mental subscale [odds ratio = 0.78; 95% confidence interval = 0.64-0.96]). Other factors associated with worse outcome scores were presence of two or more articular injuries, lower extremity injuries, and a combination of shaft and articular injuries. If patients survived, traumatic lower extremity amputation and a high initial maximum AIS (MAIS) spine score was the only predictive parameter for an increased odds of adverse clinical outcomes late after trauma. Injuries associated with these outcomes should be the focus of attention regarding injury prevention and priority in care.

Evaluation of the osteogenic and chondrogenic differentiation capacities of equine adipose tissue-derived mesenchymal stem cells

To evaluate the proliferative behavior, telomere length, immunophenotype, and differentiation capacity of equine adipose tissue-derived mesenchymal stem cells (AT-MSCs). 6 adult racing horses treated for articular Injury but otherwise healthy. AT-MSCs were Isolated from horses and expanded In Dulbecco modified Eagle medium enriched with fetal bovine serum and antimicrobials. Expression of cell surface antigens and telomere length were Investigated via flow cytometry Differentiation of MSCs Into chondrocytes, osteoblasts, and adipocytes was Induced In vitro by specific stimuli and was evaluated by analyzing marker genes with quantitative reverse transcriptase PCR assays and immunocytochemical and cytologie evaluations. Equine MSCs could be cultured up to the fifth passage before signs of senescence, apoptosis, and detachment Indicated cellular exhaustion. However, the AT-MSCs from 2 of 6 horses survived to later passages with Increased doubling rates and telomere lengths. The cells had a typical phenotype, with expression of CD14, CD73, CD90, CD105, CD140b, and CD164 antigens and a lack of CD34 and CD45 antigens. The cells also had a strong potential to differentiate Into osteoblasts, as characterized by Intense von Kossa and alizarin red staining as well as high Induction of osteopontin. Chondrogenic differentiation was detected via Alelan blue staining and expression of aggrecan and type II collagen Adipogenesis was Induced in AT-MSCs by supplementation of differentiation media with rabbit serum. Equine AT-MSCs representa suitable cellular source for regenerative treatment of bone or cartilage defects, particularly when expanded In vitro for only a few passages.

Acetabular both-column fractures: Essentials of operative management

Acetabular both-column fractures are challenging articular injuries. They usually require operative treatment. We report on fundamental elements of pathoanatomy and radiology that are reviewed as far as they may influence treatment planning and surgical intervention. Surgical strategy, choice of the most suitable approach, reduction manoeuvres and fixation techniques are presented, together with some tips and tricks that are worth knowing in the surgical reconstruction of these difficult fractures.

JEFFREY S. ABRAMS, MD, on “Pathoanatomy of First-Time, Traumatic, Anterior Glenohumeral Subluxation Events” by Lieutenant Colonel Brett D. Owens, MD, et al.

Anterior shoulder subluxation is a transitory event that can be difficult to define. Descriptive phrases in sports, such as the so-called dead-arm syndrome, reflect on the associated neurological symptoms that may occur with excessive anterior humeral translation. The military is a unique setting in which to study this disorder, since it provides information on young active individuals who must perform at a high level and comply with medical advice. Short-term and midterm data collection and repetitive examinations are routinely available. Most studies have examined dislocation events, since the pathologic event was documented by radiographs and/or there was required assistance for reduction1,2. This unique study on subluxation suggests that articular injury may explain why certain patients have recurrences or progress from subluxation to dislocation. It is important to acknowledge that this is a study of disorders with a traumatic etiology. Shoulders with increased laxity that have a momentary subluxation due to position or strain are not included in this population. We may expect to find an absence of labral injury in patients with subluxation but with no history of trauma. The authors identified a paucity …

Inhibition of acid-sensing ion channels in articular chondrocytes by amiloride attenuates articular cartilage destruction in rats with adjuvant arthritis

The aim of this study was to examine whether drugs such as amiloride that block acid sensing ion channels (ASICs) could attenuate articular cartilage destruction in adjuvant-induced arthritis (AA). Articular chondrocytes were isolated from the normal rats, and intracellular calcium ([Ca(2+)]i) was analyzed with laser scanning confocal microscopy. The cell injury was analyzed with lactate dehydrogenase release assay and electron microscopy. Amiloride or phosphate buffered saline was administered daily to AA rats for 1 week from the time of arthritis onset. Morphology of the articular cartilage was examined by hematoxylin and eosin staining, and Mankin score was calculated. The expression level of type II collagen (COII) and aggrecan mRNA and proteins in the articular cartilage was evaluated by real-time PCR and Western blotting, respectively. The rapid decrease in extracellular pH (6.0) induced a conspicuous increase in [Ca(2+)]i in the articular chondrocytes. Amiloride reduced this increase in [Ca(2+)]i, and inhibited acid-induced articular chondrocyte injury. Amiloride significantly decreased Mankin scores in the articular cartilage in AA rats. COII and aggrecan mRNA and protein expression in the articular cartilage was significantly increased by amiloride. These findings represent some experimental evidence of a potential role for ASICs in the pathogenesis of articular cartilage destruction in rheumatoid arthritis.

Acid-sensing ion channel 1a mediates acid-induced increases in intracellular calcium in rat articular chondrocytes

Acid-sensing ion channels (ASICs) are cationic channels that are activated by extracellular acidification and implicated in pain perception, ischemic stroke, mechanosensation, learning, and memory. It has been shown that ASIC1a is an extracellular pH sensor in the central and peripheral nervous systems, but its physiological and pathological roles in non-neural cells are poorly understood. We demonstrated a novel physiological function of ASIC1a in rat articular chondrocytes. The expression of ASIC1a mRNA and protein in rat articular chondrocytes was evaluated by reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting. The distribution of ASIC1a protein located in articular chondrocytes was determined by using immunofluorescence cell staining. The possible molecular mechanisms of articular chondrocytes pH sensing, as assessed by recording intracellular calcium ([Ca(2+)]i) in chondrocytes, were analyzed by using the laser scanning confocal microscopy technique. The cell injury following acid exposure was analyzed with lactate dehydrogenase release assay and electron microscopy. mRNA and protein expression showed that ASIC1a was expressed abundantly in these cells. In cultured chondrocytes, extracellular pH 6.0 increased intracellular calcium in the presence of extracellular Ca(2+). The ASIC1a-specific blocker PcTX venom significantly reduced this increase in [Ca(2+)]i, and inhibited acid-induced articular chondrocyte injury. However, the increase in [Ca(2+)]i and articular chondrocyte injury were not observed in the absence of extracellular Ca(2+). These findings show that increased [Ca(2+)]i, mediated via ASIC1a, might contribute to acidosis-induced articular chondrocyte injury.

A civilian perspective on ballistic trauma and gunshot injuries

BackgroundGun violence is on the rise in some European countries, however most of the literature on gunshot injuries pertains to military weaponry and is difficult to apply to civilians, due to dissimilarities in wound contamination and wounding potential of firearms and ammunition. Gunshot injuries in civilians have more focal injury patterns and should be considered distinct entities.MethodsA search of the National Library of Medicine and the National Institutes of Health MEDLINE database was performed using PubMed.ResultsCraniocerebral gunshot injuries are often lethal, especially after suicide attempts. The treatment of non space consuming haematomas and the indications for invasive pressure measurement are controversial. Civilian gunshot injuries to the torso mostly intend to kill; however for those patients who do not die at the scene and are hemodynamically stable, insertion of a chest tube is usually the only required procedure for the majority of penetrating chest injuries. In penetrating abdominal injuries there is a trend towards non-operative care, provided that the patient is hemodynamically stable. Spinal gunshots can also often be treated without operation. Gunshot injuries of the extremities are rarely life-threatening but can be associated with severe morbidity.With the exception of craniocerebral, bowel, articular, or severe soft tissue injury, the use of antibiotics is controversial and may depend on the surgeon's preference.ConclusionThe treatment strategy for patients with gunshot injuries to the torso mostly depends on the hemodynamic status of the patient. Whereas hemodynamically unstable patients require immediate operative measures like thoracotomy or laparotomy, hemodynamically stable patients might be treated with minor surgical procedures (e.g. chest tube) or even conservatively.

Locked volar plating for complex distal radius fractures: Patient reported outcomes and satisfaction

BackgroundDistal radius fractures are common. The increasing prevalence of osteoporosis contributes to frequently complex articular injuries sustained even after low energy falls. The best method of treating complex type C distal radius fractures is debated. Locked volar plating and external fixation are both widely used with good reported results. Measures of success are traditionally based on technical measurements or the perception of the surgeon. Patient reported measures of outcome are increasingly recognised as important markers of surgical success. We report our experience using locked volar plating for complex type C distal radius fractures as well as patient reported measures of success and satisfaction.MethodsOver a 12 month period we treated 21 patients with type C distal radius fractures using locked volar plating. These patients were followed up for at least 12 months and the outcome was assessed using clinical examination, grip strength measurements, radiographs and Patient Rated Wrist Evaluation (PRWE) scoring.ResultsThe 21 patients studied had an average age of 48 years. There were 8 men and 13 women. All of the fractures had united by 3 months. There were no cases of wound infection or tendon injury/irritation. Patients reported low pain scores, good patient rated wrist evaluation scores and high levels of satisfaction.ConclusionsLocked volar plating for complex distal radius fractures produces good results when assessed using patient reported measures of outcome. Further work should address whether locked volar plating offers superior outcomes and patient satisfaction compared to external fixation.

Predicting the effects of knee focal articular surface injury with a patient-specific finite element model

Successful focal articular surface injury (FAI) repair depends on appropriate matching of the geometrical/material properties of the repaired site, and on the overall dynamic response of the knee to in-vivo loading. There is evidence linking the pathogenesis of lesion progression (e.g. osteoarthritis) to weightbearing site and defect size. The paper investigates further this link by studying the effects of osteochondral defect size on the load distribution at the human knee. Experimental data from cadaver knees ( n = 8) loaded at 30° of flexion was used as input to a validated finite element (FE) model. Contact pressure was assessed for the intact knees and over a range of circular osteochondral defects (5 mm to 20 mm) at 30° of flexion with 700 N axial load. Patient specific FE models and the specific boundary conditions of the experimental set-up were used to analyze the osteochondral defects. Stress concentration around the rims of defects 8 mm and smaller was not significant and pressure distribution was dominated by the menisci. Experimental data was confirmed by the model. For defects 10 mm and greater, distribution of peak pressures followed the rim of the defect with a mean distance from the rim of 2.64 mm on the medial condyle and 2.90 mm on the lateral condyle (model predictions were 2.63 and 2.87 mm respectively). Statistical significance was reported when comparing defects that differed by 4 mm or greater (except for the 5 mm case). Peak rim pressure did not significantly increase as defects were enlarged from 10 mm to 20 mm. Peak values were always significantly higher over the medial femoral condyle. Although the decision to treat osteochondral lesions is multifactorial, the results of this finite element analysis indicate that a size threshold of 10 mm, may be a useful early adjunct to guide clinical decision-making. This modified FE method can be employed for in-vivo studies.

Intermetatarsal Fat Pad Sign: Radiographic Aid to Diagnosis of Occult Tarsometatarsal Joint Injuries

AJR 2009; 192:W36–W37 0361–803X/09/1921–W36 © American Roentgen Ray Society Intermetatarsal Fat Pad Sign: Radiographic Aid to Diagnosis of Occult Tarsometatarsal Joint Injuries Lisfranc tarsometatarsal fracture–disloc­ ations are well­described injuries usually resulting from forced plantar flexion or direct blow or crush trauma to the forefoot. Although this is a relatively rare injury, timely recognition is essential because misdiagnosis can lead to chronic pain and instability in this patient population. Lisfranc injuries account for less than 1% of all fractures and have a reported incidence of one per 55,000 persons; however, the overall incidence may be more common than is generally recognized because misdiagnosis has been reported to occur in approximately 20% of all cases [1, 2]. Conventional radiographs, including weight­ bearing­view images, can reveal fractures of the metatarsal bases, and dis placement of the bases in advanced cases, but can be unreli­ able in the detection of subtle injuries and iso lated ligamentous injuries without bone frac tures [3]. Subtle malalignment of the tarsal–metatarsal junction can be difficult to diagnose radiographically. Norfray et al. [4] have even suggested that 1–2 mm of tarso­ metatarsal malalignment may be normal. The reason for this diagnostic dilemma lies in the fact that overlapping shadows, inappropriate positioning, and sub optimal exposure parame­ ters can make correct evaluation of osseous land marks difficult [4]. Despite its limitations in revealing the full extent of tarsometatarsal injury, radiography is often the first examination performed after the initial clinical examination. Mis diagnosis is highest in cases of isolated ligamentous injury with no visible fracture on the radiograph and in which metatarsal cuneiform offset may be subtle or absent. We have pro­ vided images of such a case, and we describe an interesting soft­tissue radiographic find­ ing that, to the best of our knowledge, has not been previously described. We have called this the “intermetatarsal fat pad sign.” Similar to the sail sign of olecranon and coronoid fossae fat pad displacement seen with intra­ articular injury to the elbow, we show that edema and hemorrhage from a Lisfranc ligamentous injury may also produce a radio­ graphically apparent displaced inter metatarsal fat pad (Fig. 1). We believe that awareness of the intermetatarsal fat pad sign may be of aid in the diagnosis of subtle radio graphic pre­ sentations of Lisfranc injury. Vincent Timpone Michael Tall Andrew Puckett David Grant U.S. Air Force Medical Center Travis Air Force Base, CA 94535

Akuter, traumatischer versus chronischer Knorpelschaden unter gutachterlichen Gesichtspunkten

Have chondral lesions been found in the course of an articular injury? Are these lesions of traumatic or degenerative origin? Is it possible to differentiate traumatic from pre-existing pathology with the help of history, clinical findings and imaging features? The answers to these questions are of paramount importance in the setting of legal expert assessment. The diagnosis of an acute traumatic chondral injury is based on arthroscopic and/or MRI findings. MRI is the diagnostic method of choice in a suspected isolated chondral injury. The method yields high accuracy in detecting chondral and osteochondral lesions. The MRI finding of a concomitant subchondral bone contusion ("bone bruise") adjacent to a cartilage lesion helps in the diagnosis of acute chondral lesions. Traumatic bone marrow alterations regress in most cases over the course of 6 months. For this reason the initial MRI should be performed within 1 to 6 weeks after trauma. A follow-up study should be undertaken not prior to 3 months after injury. Osteoarthritic cartilage lesions show a distinct regional pattern on MRI usually affecting the weight-bearing regions. In advanced stages, regularly concomitant osseous reactions such as osteophytes, subchondral sclerosis and bone attrition are observed. Subchondral bone marrow lesions in osteoarthritis show a tendency to progress. The direct inspection and probing of the joint during arthroscopy allows for a detailed assessment of the chondral surface and the diagnosis of possible cartilage softening. An arthroscopic differentiation between acute traumatic chondral lesions and chronic cartilage alterations is possible in most cases within the first 6 to 12 weeks after injury.