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Background: The use of coring instrumentation for osteochondral allograft (OCA) transplantation of the femoral trochlea is challenging due to the complex topography of this anatomical area. Purpose: We sought to determine the effect of flat guides versus guides contoured to the surface of the trochlea on graft step-off in trochlear OCAs performed on a foam bone model. We also determined the effect of surgeon experience level and graft size on step-off. Study Design: Controlled laboratory study. Methods: Allograft harvesters were produced in 3 different sequential sizes with either a flat or a contoured undersurface. The guides matched one another in all aspects of shape and size except for the undersurface contour. The contoured undersurface generally matched the surface of the bone model trochlea but was not customized to that surface. A total of 72 foam femora were obtained. Identical trochlear stellate lesions of 3 different sizes (small, medium, and large) were created using 3-dimensional printed surface templates. A total of 6 surgeons (3 attending and 3 resident surgeons) performed OCAs of each trochlear lesion. Each surgeon performed 1 graft for each size and each guide type (n = 6 per surgeon). A specialized digital caliper was prepared that allowed the measurement of graft step-off to within 0.01 mm at a distance of 5 mm between the 2 sensors. The measurements were performed at 8 positions around the clockface of the grafts. Results: Grafts performed with the contoured guides had a mean step-off of 0.43 ± 0.37 mm. Grafts performed with the flat guides had a mean step-off of 0.74 ± 0.78 mm ( P < .0001). Experience level did not have a significant effect on graft step-off ( P = .81). There was no identifiable pattern indicating higher step-off at any one position on the clockface. Conclusion: In this study, contoured grafts had significantly lower step-offs compared with flat guides. Experience level, clockface position, and graft size did not affect step-off.

Hip preservation has emerged as a developing surgical subspecialty with a variety of tools to address hip joint pain and dysfunction. Cartilage tears and delamination are caused by injury to the hip and can ultimately progress to osteoarthritis. It has been established that the acetabulum is particularly at risk of cartilage injury secondary to trauma, hip dysplasia and hip impingement. In spite of the high frequency of acetabular cartilage lesions based on our experience and the literature, there is no consensus as to the optimal treatment of these lesions. This review article highlights the challenges in treating cartilage injuries of the acetabulum with a particular emphasis on published studies and technical considerations in performing these procedures.

Background and aim: learning environment in the process of medical education and the impact of the professional behavior of learners on the basis of their understanding of learning environments is special role The aim of this systematic literature review was evaluation Identify the Dentistry Students perception of the LE. Materials and methods: Some papers retrieved with the use of the search strings were chosen via consideration of specific criteria for ensuring their relevance and whether they were able to reply each RQ. Upon reading the full-text papers, all included studies meeting inclusion criterion that considered the titles, abstracts, as well as keywords, was regarded as the pertinent paper. Conclusion: Recommended to plan appropriately for holding educational courses and preparation of conditions, facilities and suitable environment for growth of these educational approaches.

Morphological abnormalities such as cam deformity or growth disturbances can have a detrimental effect on the smooth function of the hip joint. This case reports an attempt to salvage the hip joint of a young patient with a posttraumatic growth disturbance of the femoral head using a fresh osteochondral allograft. This treatment has been used very rarely in the femoral head due to the presumed tenuous blood supply of the head and the perceived risk of nonunion or progressive avascular necrosis. The patient in this case had persistent pain and mechanical symptoms leading to hip replacement. A detailed analysis of the retrieved femoral head demonstrated durability and healing of the grafts based on gross inspection, histology of bone and cartilage, and microCT analysis. This case is the first report to our knowledge of a detailed histological and radiographic analysis of the fate of osteochondral allografts of the femoral head. We hope that this case provides justification for the use of osteochondral allografts of the femoral head for other indications such as femoral head fractures, avascular necrosis, and benign epiphyseal tumors of the femoral head in an effort to avoid arthroplasty in young patients. The authors have obtained the patient’s informed written consent for print and electronic publication of the case report.

In the current study, a succession from the middle part of the Sarcheshmeh Formation was investigated to record the early Aptian oceanic anoxic event 1a (OAE1a) at the Qaleh-Zoo section in the central part of the Kopet-dagh Basin. The OAE1a has been recorded on a global scale during the early Aptian in the NC6B nannofossil biozone. In this study the interval from the uppermost part of NC6A to the lowermost part of NC7A (early Aptian) was investigated at Sarcheshmeh Formation. Calcareous nannofossil paleoecology and carbonate calcium contents were analyzed to identify the OAE1a interval. Rare presence or absence of nannoconids at NC6B along with the lowest values of carbonate calcium contents indicate the effect of OAE1a in the study section (55 to 180 meters of the studied interval). Regarding these data (calcareous nannofossils and carbonate calcium contents), the OAE1a was recorded at the middle part of Sarcheshmeh Formation which is equivalent with this event at the western part of the Kopet Dagh Basin (Takal Kuh section). Keywords: CalcareousNannofossils; Kopet-Dagh Basin; Oceanic Anoxic Event 1a (OAE1a); Sarcheshmeh Formation. Introduction The early Aptian OAE1a is one of the most important events in terms of temperature and paleoceanography during the Cretaceous. OAE1a is regarded as an anoxic condition that is continued for at least one million years. This event is recorded in the Early Aptian time and NC6 calcareous nanofossil biozone on a global scale (Erba 2004). Calcareous nanoplanktons are one of the most abundant planktonic groups in the seas that changes in their assemblages reflecting changes in temperature and nutrient content of the oceans (Herrle and Mutterlose 2003; Herle 2003; Tremolada et al. 2006). In terms of calcareous nanofossil distribution, the nanoconid crisis (being rare or absent in fossil assemblage) is a global event that is an evidence of OAE1a (Erba 1994, 2004). Calcium carbonate content in the sediments is also very low during this time interval which is considered as a signal for this event (Erba and Tremolada 2004). At the current study, the OAE1a is investigated based on calcareous nannofossils at the Kopet-Dagh Basin. The Kopet-Dagh Basin is located on the northeast of Iran, extending over Iran, Turkmenistan and Afghanistan with a west-northwest to east-southeast trend. The Iranian part of the basin is located between 61°14ˊ and 54°00ˊE and 38°15ˊ and 35°38ˊ N. Cretaceous sediments are well developed and extensively exposed in the Kopet-Dagh Basin and the Sarcheshmeh Formation was precipitated during the Early Cretaceous in this basin. In order to determine the OAE1a interval, the middle part of the Sarcheshmeh Formation in the Qale-Zoo section at the central part of the Kopet-Dagh Basin has been investigated based on calcareous nanofossils. Material & Methods The Qaleh-Zoo section is located 15 km to the northwest of Shirvan and 2.5 km to the west of Ziarat village at N 37°29ˊ39˝ and E 57°48ˊ07˝. The Sarcheshmeh Formation with 713 m thickness in Qaleh-Zoo section is conformably overlies the Tirgan Formation and is in turn overlain by the Sanganeh Formation. Regarding calcareous nannofossil biostratigraphic analysis of the Sarcheshmeh Formation (Gholamifard et al. 2016), 305 m thickness (from sample 110 to 196) with 86 samples from NC6A to NC7A biozones were analyzed in detail. Calcareous nannofossil paleoecology and calcimetry were performed in these samples to determine the OAE1a event. The studied interval mainly consists of shale, marl, argillaceous limestone and limestone. For biostratigraphic analysis, all of the samples were processed using the gravity settling technique (Bown and Young 1998) and the prepared slides were observed under a Leica DMLP Pol light microscope at ×1000 magnification. For paleoecological analysis a semi-quantitative count was done according to Burnett et al. (1998) and the taxa are classified into abundant (A= more than 10 species per field of view), common (C= 1 to 10 species per field of view), Few (F= one species in 2 to 50 fields of view) and rare (R= one species in more than 50 fields of view). The carbonate calcium content of the sediments is also measured with Schibler calcimeter by measuring the amount of CO2 gases released during the analysis as follow: CaCO3% =1/2 × 0/2 × δH(sample) / weight(sample) / δH(standard) × 100 Discussion of Results & Conclusions The calcareous nannofossils of the studied interval include species with global distribution (such as Watznaueria spp., Rhaghodiscus spp., Zeugrhabdotus spp., Micrantholithus spp. and so on) and nanoconids (commonly found in the Tethys Basin). According to calcareous nanofossil data, the oceanic anoxic event 1a of the early Aptian has been reported in various parts of the world from the upper parts of the Chiastozygus litterarius (NC6) and the first part of Rhagodiscus angustus (NC7A) biozones (Erba 1994, 2004). Regarding calcareous nannofossil biostratigraphy of the studied interval, the presence of these biozones at the studied succession was determined. Paleoecological studies indicate of nanoconid crisis and low calcium carbonate content of sediments from sample 128 to 157 at the studied succession (upper part of NC6 zone and beginning of NC7A subzone) that must be the result of early Aptian OAE1a at the middle part of Sarcheshmeh Formation. This interval can be correlated with OAE1a that is identified at the western Kopet-dagh Basin (Takal Kuh section) in the first part of Sanganeh Formation by Mahanipour et al. (2011).

A biostratigraphic study based on the planktonic foraminifera and isotope stratigraphy of the Cenomanian-Turonian interval has been undertaken in the western part of the Kopet-Dagh Basin (NE Iran). In this research, two stratigraphic sections including: Maraveh Tappeh and Qareh Galdy have been sampled and studied. Based on planktonic foraminifera, three biozones were assigned to this interval. These are the Rotalipora cushmani Zone, Whiteinella archaeocretacea Zone and Helvetoglobotruncana helvetica Zone, These biostratigraphic data confirm a gradual faunal turnover of planktonic foraminifera, at the Cenomanian-Turonian boundary in Whiteinella archaeocretacea Zone characterized by: absences, low abundance and disappearances of complex morphotypes. After this event, in Helvetoglobotruncana helvetica Zone, along with simple globular chamber morphotypes, single keeled and double-keeled morphotypes appeared and flourished. The carbon-isotope curves in both sections, record a negative shift values below the Aitamir-Abderaz formations boundary in Whiteinella archaeocretacea Zone, and then, a positive excursion of about 5.50‰, along with several fluctuations are well evident in both sections. The δ18O values show, from the bottom to the top, a gradual increase of averagely 2‰. Based on these results, the Cenomanian-Turonian succession in this part of the Kopet-Dagh Basin is continuous and corresponds to the siltstone and chalky limestone layers of the upper part of the Aitamir Formation and the lower part of the Abderaz Formation.

29 pages; International audience; A high-resolution stratigraphic analysis of the Upper Cretaceous Gurpi Formation has been undertaken in the Shahneshin section (Zagros Basin, Iran). New results on calcareous nannofossils, planktic foraminifers, dinoflagellate cysts and high-resolution carbon and oxygen stable isotopes form the basis of a reference section for the eastern Tethys that spans the upper Coniacian to the late Danian. Carbon-isotope correlation to Gubbio, Italy and the NW German chalk allows for the identification of many isotopic events as well as for the definition of new events in the Campanian and Maastrichtian. Our results allow for a review of the accurate position of the Coniacian/Santonian, Santonian/Campanian, and Campanian/Maastrichtian stage boundaries relative to carbon isotopes and plankton bioevents. The reliability of Coniacian to Maastrichtian planktic foraminifer, dinoflagellate cysts and calcareous nannofossil biohorizons is assessed.

In order to investigate the depositional history and facies architecture of the Campanian-Danian interval of the Zagros Basin, the succession of the Gurpi Formation (Fm.) was examined in the Gandab section, southwestern Lurestan Province, through an integrated study of calcareous nannofossils, planktic foraminifera, and bulk carbonate carbon isotopes. Despite the persistent occurrence of reworked fine fraction carbonates as attested by microfossils across the investigated interval, the carbon isotope stratigraphy of Lurestan shows a good correlation with those in the eastern and western Tethys from the Shahneshin section in central Zargos (Fars Province) and Gubbio of northern Apennines in Italy (Gubbio). The succession can be assigned an age range from late Campanian to early Danian based on the integrated stratigraphy. The results from the Gandab section, as well as field observations in more northeasterly areas of Lurestan, point to lateral facies variation of the Campanian–Danian interval associated with tectonic activity during the Late Cretaceous-Paleogene of the Zagros Basin. According to the known distribution of facies across the SW-NE transect of Lurestan and detailed ages delineated in the Gandab section, a schematic model of syntectonic sedimentation and facies distribution is drawn. Our model illustrates how the continental convergence and closure of Neo-Tethys resulted in uplifting/subsiding of the basin floor, shifting in depocenter, significant changes in sedimentary facies, and reworking phenomena in the Lurestan region., CVU acknowledges funding from the Natural Environment Research Council (NERC) (grant no. NE/N018508/1).

Planktonic foraminiferal biostratigraphy and isotope stratigraphy analyses of Turonian-Maastrichtian deposits have been carried out in the western part of the Kopet-Dagh Basin. The identification of the planktonic foraminiferal assemblages has led to the recognition of twelve Upper Cretaceous zones (Helvetoglobotruncana helvetica Zone to the Contusotruncana contusa-Abathomphalus mayaroensis zone) from the Tethyan realm. The obtained stable carbon isotope profile correlates with other reference curves, revealing many Late Cretaceous events including the Hitchwood, Navigation, Light Point, East Cliff, White Fall, Late Campanian Event (LCE), Campanian-Maastrichtian Boundary Event (CMBE), Middle Maastrichtian Event (MME) and KPg Events (KPgE). The Turonian-Maastrichtian deposits of the studied area represent severe changes in sedimentation rate and several hiatuses and condensed intervals, which mostly coincide with lithological boundaries. The data indicate a general shallowing -upwards in association with the Late Cretaceous tectonics of the Kopet-Dagh Basin. The reconstruction of the age model allows a discussion of the results in terms of changes in palaeoenvironmental conditions (eutrophic vs. oligotrophic).

Middle Triassic carbonate sequences of Shotori Formation have a thickness of 70 m and are deposited Robat-e-Kalmard region of Tabas city in Central Iran basin. Gradationally and conformably overlying Sorkh shale Formation, Shotori Formation, mostly composed of medium to thick dolomites (50 m), interbeded with thin lime and sandstones, is disconformable by a laterite horizon at its upper boundary. This Formation mainly consists of fine-to-coarsely crystalline dolomites. According to petrographic (fabric and grain size) and geochemical (elemental analysis of Ca, Mg, Na, Sr, Fe, Mn) evidence, five various types of dolomites were recognized in Shotori Formation. This variety results from early and late diagenetic processes, triggering a change in dolomitizing fluids and thereby forming various dolomites. Geochemical studies have revealed that the dolomites of Shotori Formation have formed under meteoric diagenesis and reducing conditions. Various dolomitization mechanisms are proposed for various types of dolomites; that is to say, Sabkha model is considered for type 1 dolomite, mixing zone model for type 2 and 3 dolomites and burial model for type 4 and 5 dolomites.

A high-resolution study of carbon isotope stratigraphy and calcareous nannofossil biostratigraphy has been undertaken on the Upper Cretaceous sediments of the Gurpi Formation (Fm.) in the Bowan section (Zagros Basin, Iran). The integrated stratigraphy of the section allows for large-scale correlation with Upper Cretaceous reference sections (Gubbio, Italy; German Chalk; Shahneshin, Iran) and suggests the age of the Gurpi Fm. at Bowan to be latest Santonian to early Selandian. Correlation of the isotopic data from Bowan to the Shahneshin section in the central Zagros mountains shows remarkable similarity that may be related to effects specific to the peculiar stratigraphy of the area and, possibly, to the long-term evolution of seawater δ13C in the Zagros Basin. A sequence stratigraphic framework is proposed for both sections. Correlation of the two sections to data from the Boreal realm, Indian Ocean, equatorial Pacific Ocean, and other Tethyan sections suggests that it is possible to identify some of the previously defined major carbon isotope events in the Iranian sections. Significant differences, however, are observed in absolute values and overall amplitude of carbon isotope trends. In particular, our results show that the Santonian/Campanian boundary event (SCBE) which is a well-defined, double-peaked, positive excursion at Gubbio and in the Boreal realm is absent in the Zagros Basin, eroded by a major sequence boundary. Moreover, the most pronounced feature in Upper Cretaceous carbon isotope ratios of the Zagros Basin carbonates is an overarching maximum culminating in the early Campanian which correlates with a discrete, low-amplitude (0.25‰) positive excursion defined as the papillosa Zone event at Gubbio and in the Boreal realm. Our results thus reveal a contrasting evolution of carbonate δ13C during the early Campanian between different oceanic basins but also within the Tethys.

Biostratigraphy, using foraminifera and echinoids, plus high-resolution carbon isotope stratigraphy of the upper Maastrichtian–Danian interval in the western part of the Kopet-Dagh Basin in northeast Iran are outlined. Our study of shallow-marine carbonate platform deposits of the Kalat Formation, rich in larger benthic foraminifera (predominantly Clypeorbis mammillatus Schlumberger, Lepidorbitoides sp. and Siderolites calcitrapoides Lamarck), has allowed the definition of a C. mammillatus-S. calcitrapoides Assemblage Zone, of late Maastrichtian age. Clypeorbis mammillatus is here recorded for the first time from the Maastrichtian Kalat Formation and represents the most easterly find of this taxon in the European faunal province. From Danian strata of the Chehel Kaman Formation three genera (Cyclaster, Echinocorys and Pseudogibbaster) and four species of echinoids were identified. In addition, three planktonic foraminiferal biozones are introduced here for the Danian interval of the Chehel Kaman Formation studied, i.e., Guembelitria cretacea Zone, Eoglobigerina eobulloides–Subbotina triloculinoides Interval Zone (Pα-P1a) and Subbotina triloculinoides Subzone (P1b). The isotope profile obtained correlates with the subtropical Bottaccione/Contessa reference curve for the K/Pg boundary interval and, on a regional scale, with the Maraveh Tapeh section, which represents the δ13C positive excursion of KPg-2 and the upper negative excursion of the KPg-3. The K/Pg boundary, placed at the δ13C maximum above KPg-3, corresponds in the Qareh Galdy section with sample 2239.

این مطالعه به بررسی توالی رسوبات کرتاسه زیرین شامل سازندهای سرچشمه و سنگانه در خاور منطقه کپه داغ ( برش چینه‏شناسی باغک) از نقطه نظر پالینولوژیکی می‏پردازد. بر اساس مطالعات انجام شده ، 25 جنس و 31 گونه داینوفلاژله شناسایی گردید. با توجه به داینوفلاژله‏های شناسایی شده و با استفاده از مطالعه فرامینیفرهای موجود در این برش سن بارمین پسین-آپتین پیشین برای سازند سرچشمه و سن آپتین میانی- آلبین میانی برای سازند سنگانه در برش چینه‏شناسی باغک تعیین گردید. تجمع داینوفلاژله‏های شناسایی شده در برش مورد مطالعه با بخشی از بیوزون Odontochitina operculata zone انطباق دارند. بررسی سه گروه اصلی از عناصر پالینولوژیکی (فیتوکلاست‏ها، پالینومورف‏های دریایی و مواد آلی فاقد ساختمان) و نتایج حاصل از مطالعه آماری فاکتورهای مؤثر بر درجه حفظ شدگی مواد ارگانیکی مانند فاکتور حفاظت از مواد ارگانیکی (Lability) و نسبت پالینومورف های دریایی به AOM و همینطور نسبت AOM شفاف به AOM تیره نشان می دهد نرخ رسوب‌گذاری و میزان اکسیژن محیط متغیر بوده و از سمت سازند سرچشمه به سمت سازند سنگانه عمق محیط افزایش یافته و شرایط کم انرژی تر و آرام تر و با میزان کمتری از اکسیژن بر محیط رسوبی غالب گشته است. داینوفلاژله های شاخص محیط رسوبی نیز نشان می دهند که سازندهای سرچشمه و سنگانه در محیط نرتیک داخلی تا نرتیک خارجی نهشته شده اند.

This report describes the arthroscopic management of a case of incarcerating pincer-type femoroacetabular impingement. The hip joint had a marked restriction of range of motion and secondary pain as a result of osteophytes wrapping around the femoral head down the femoral neck. The patient was treated with staged bilateral hip arthroscopy. The procedures were initially performed through the peripheral compartment to remove the incarcerating acetabular rim, followed by arthroscopy of the central compartment with acetabuloplasty and femoral head osteochondroplasty. The patient's treatment has led to an excellent clinical and radiographic result at 24 months' follow-up despite an unrelated pelvic fracture sustained in the postoperative period. This technique emphasizes the capabilities of hip arthroscopy in advanced cases of femoroacetabular impingement as an alternative to arthroplasty for patients with healthy articular cartilage.

Deposition of organic rich black shales and dark gray argillaceous limestones in the Berriasian–Turonian interval has been documented in many parts of the world. Northwest of Zagros, Iran (Lurestan zone), thin bedded black shales and marls, dark gray argillaceous limestones and fissile limestone layers, having bitumen, of the Garau Formation are deposited. For biostratigraphic studies two stratigraphic sections including one surface section (Kuzaran) and one subsurface section (Naft well) were selected, respectively. In this study, 61 foraminiferal species belonging to 17 genera have been identified, and 12 biozones were recognized. Based on fossils distribution and biozones identification, the age of the Garau Formation is Berriasian?–early Cenomanian. In addition, the micropalaeontological study demonstrated a variety of widespread morphological changes in planktonic foraminifera assemblages (e.g., the elongation of the final chambers, appearance of twin chambers in the last whorl). These changes coincide with deposition of argillaceous limestones and marls rich in organic matter, indicating oceanic anoxic events. On this basis, three oceanic anoxic events such as OAE1a, OAE1b and OAE1d were recognized in Naft well section and two (OAE1b and OAE1d) in Kuzaran section.

The present study identify the important of the level of access to capital market on Tehran stock exchange with attention to opening 21 regional markets and use of PAM software in Iran. The goal of the present study is to find out about the effect of two factors on Tehran stock exchange: A)The effect of the geographical spread of regional markets on Tehran stock exchange performance. B)The effect of the use of information and trading software on four indices:1. The number of the traded stocks,2. The value of the traded stocks,3. The number of traders, and 4. The changes of the total index in Tehran stock exchange. To study of this subject we employed Kolmogorov-Smirnov and then Two tail test respectively and The study is done during an era of two years, that is a year before and a year after the geographical spread of the regional markets and the use of the PAM software and then We have used the SPSS software for statistical analysis. It was found that if the standard is the total index, then the geographical spread of the regional markets has had a positive effect on Tehran stock exchange. But such result cannot be concluded for those three factors. Simultaneously, it cannot be concluded that the use of the new software has caused an increase in the standards of evaluating the stock performance that is the number and the value, the number of the traders and the stock traded and the total index in Tehran stock exchange and as a result improving its performance.

Background: It is unclear whether simultaneous-bilateral total knee arthroplasty is as safe as staged-bilateral arthroplasty is. We are aware of no randomized trials comparing the safety of these surgical strategies. The purpose of this study was to retrospectively compare these two strategies, with use of an intention-to-treat approach for the staged-bilateral arthroplasty cohort. Methods: We used linked hospital discharge data to compare the safety of simultaneous-bilateral and staged-bilateral knee arthroplasty procedures performed in California between 1997 and 2007. Estimates were generated to take into account patients who had planned to undergo staged-bilateral arthroplasty but never underwent the second procedure because of death, a major complication, or elective withdrawal. Hierarchical logistic regression modeling was used to adjust the comparisons for patient and hospital characteristics. The principal outcomes of interest were death, a major complication involving the cardiovascular system, and a periprosthetic knee infection or mechanical malfunction requiring revision surgery. Results: Records were available for 11,445 simultaneous-bilateral arthroplasty procedures and 23,715 staged-bilateral procedures. On the basis of an intermediate estimate of the number of complications that occurred after the first procedure in a staged-bilateral arthroplasty, patients who underwent simultaneous-bilateral arthroplasty had a significantly higher adjusted odds ratio (OR) of myocardial infarction (OR = 1.6, 95% confidence interval [CI] = 1.2 to 2.2) and of pulmonary embolism (OR = 1.4, 95% CI = 1.1 to 1.8), similar odds of death (OR = 1.3, 95% CI = 0.9 to 1.9) and of ischemic stroke (OR = 1.0, 95% CI = 0.6 to 1.6), and significantly lower odds of major joint infection (OR = 0.6, 95% CI = 0.5 to 0.7) and of major mechanical malfunction (OR = 0.7, 95% CI = 0.6 to 0.9) compared with patients who planned to undergo staged-bilateral arthroplasty. The unadjusted thirty-day incidence of death or a coronary event was 3.2 events per thousand patients higher after simultaneous-bilateral arthroplasty than after staged-bilateral arthroplasty, but the one-year incidence of major joint infection or major mechanical malfunction was 10.5 events per thousand lower after simultaneous-bilateral arthroplasty. Conclusions: Simultaneous-bilateral total knee arthroplasty was associated with a clinically important reduction in the incidence of periprosthetic joint infection and malfunction within one year after arthroplasty, but it was associated with a moderately higher risk of an adverse cardiovascular outcome within thirty days. If patients who are at higher risk for cardiovascular complications can be identified, simultaneous-bilateral knee arthroplasty may be the preferred surgical strategy for the remaining lower-risk patients. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Venous malformations are a subset of low-flow vascular malformations. These are usually present at birth and grow commensurate with the child. The treatment of low-flow vascular malformations has been studied extensively. Many interventions have been devised to benefit this patient population in regard to the pain, ulcerations, infections, cosmetic concerns, and overall bulk associated with these malformations. Treatment can begin with compression garments. Another treatment is sclerotherapy. This can be done as a stand-alone treatment or as an adjunct to surgical excision. Percutaneous sclerosis of venous malformations has an efficacy of between 74 and 90% in relieving symptoms. We present a case of percutaneous sclerotherapy with Sotradecol and ethanol into an extensive lower extremity venous malformation in the setting of orthopedic megaprosthesis. We feel that this led to extensive soft tissue necrosis and infection of the limb and created a precipitous situation.

In this investigation, the influence of hyperbaric oxygen (HBO) therapy on the survival of a replanted extremity subjected to prolonged warm ischaemia is evaluated. Among the relative contraindications to replantation are prolonged warm ischaemia time, since an obstruction to blood reflow ('no-reflow phenomenon') may occur in amputated parts that are subjected to more than 6h of warm ischaemia. Twenty-three rat hindlimbs were amputated and subjected to 4h of normothermic ischaemia. The average weight of the animals was 500 gm, and re-plantation of the hindlimb was performed by bone fixation followed by microvascular anastomosis of the femoral vessels. Limb re-vascularisation was confirmed at the end of all procedures by the milk test, clinical assessment and pulse oximetry recordings (>90%). Eleven animals served as a control group and no further therapy was instituted, whereas 12 animals served as the study (replantation) group and were subjected to HBO therapy for 3 days postoperatively. The therapy was conducted in a large animal chamber for 90 min at 2.5 ata. Limb survival was assessed by capillary refill upon compression, skin turgor assessment and colour. Confirmation of clinical findings was conducted with daily pulse oximetry readings of >90%. Animals were followed up for 7 days at which point all animals were euthanized or were euthanized earlier if a non-viable limb was present. Two of the 11 limbs in the control group survived following re-plantation, whereas eight of the 12 limbs in the experimental HBO group survived at least 7 days following replantation. This difference was statistically significant (p=0.0361) using chi-square analysis and Fisher's exact test. Although re-plantation of an amputated extremity after prolonged warm ischaemia is considered a relative contraindication due to the possibility of poor outcomes, our results indicate that the window for replantation may be increased if adjunctive HBO therapy is employed in the postoperative period.

Several studies support the concept that, for optimum range of motion in THA, the combined femoral and acetabular anteversion should be some constant or fall within some “safe zone.” When using a cementless femoral component, the surgeon has little control of the anteversion of the component since it is dictated by native femoral anteversion. Given this constraint, we asked whether the surgeon should use the native anteversion of the acetabulum as a target for implant position in THA. Forty-six patients scheduled for primary THA underwent CT scanning and preoperative planning using a computer workstation. The native acetabular anteversion and the native femoral anteversion were measured. Prosthetic femoral anteversion was measured on the workstation by three-dimensional templating of a straight-stemmed tapered implant. The mean of the sum of the native acetabular anteversion and native femoral anteversion was 28.9°; however, 17% varied by 10° to 15° and 11% by more than 15°. The mean of native femoral anteversion and prosthetic femoral anteversion was 13.8° (range, −6.1°–32.7°) and 22.5° (range, 1°–39°), respectively. Based on our data, we believe the surgeon should not use the native acetabular anteversion as a target for positioning the acetabular component.

We present 2 cases of cam/pincer combined femoroacetabular impingement treated arthroscopically with labral debridement, acetabuloplasty, and femoral head recontouring. In both cases there was essentially no evidence of osteoarthritis of the hip. However, in both cases raised exostoses were evident on the anterolateral femoral neck in the region that commonly comes into contact with the acetabular rim. On the basis of 3-dimensional dynamic reconstructions, we surmise that these exostoses are a direct result of linear contact between the femoral neck and acetabular rim. We recommend that the presence of these exostoses be carefully noted by the arthroscopic hip surgeon and that they be a geographic marker of the zone of contact between the head-neck junction and the acetabular rim and a guide for the area of head osteochondroplasty in combination with appropriate treatment of the acetabular rim.

Analysis of deformity and subsequent correction are the basis for many orthopaedic surgical procedures. In advanced cases of joint degeneration, arthroplasty may be the only available treatment option. Until recently, these analyses and preoperative surgical plans have been performed using standard radiographs, tracing paper, and/or plastic overlays. Numerous customized, commercially available, computer-based preoperative planning software programs have been introduced. The purposes of this study were to describe (1) the techniques used in deformity analysis and preoperative surgical planning using standard radiographs for joint arthroplasty and corrective osteotomies of the extremities, (2) the use of computed tomography (CT) scans to analyze rotational deformities in the presence and absence of joint prostheses and in planning corrective rotational osteotomies or revision joint replacement, and (3) the techniques for analyzing angular deformities of the spine. All these applications were performed with a widely available image analysis software.

Osteomyelitis is an acute or chronic inflammatory process of the bone and its related structures secondary to an infection with pyogenic organisms. Because of the variety in disease presentations and pathophysiology of osteomyelitis, it is very difficult to evaluate in clinical studies. Therefore, animal models have been created for in vivo experimentation. A PubMed and OVID search was performed on March 31, 2008, using keywords osteomyelitis, animal model (rabbit, rat, mouse, avian, dog, sheep, and goat), and experimental osteomyelitis. The objective of this review was to provide a literature review of the animal models created to study osteomyelitis. The models were chosen based on historical relevance and clinical applicability. Numerous animal models exist to study both acute and chronic osteomyelitis. Many models have been created that allow investigators to study various aspects in the treatment and diagnosis of osteomyelitis. Based on the needs of investigators, an animal model must be carefully selected for ideal research, as no single model encompasses all aspects of osteomyelitis.

PURPOSE: Recent advances in computer-modeling software allow reconstruction of facial symmetry in a virtual environment. This study evaluates the use of preoperative computer modeling and intraoperative navigation to guide reconstruction of the maxillofacial skeleton. METHODS: Three patients with traumatic maxillofacial deformities received preoperative, thin-cut axial CT scans. Three-dimensional reconstructions, virtual osteotomies, and bony reductions were performed using MIMICS planning software (Materialise, Ann Arbor, MI). The original and “repaired” virtual datasets were then imported into an intraoperative navigation system and used to guide the surgical repair. RESULTS: Postoperative CT scans and photographs reveal excellent correction of enophthalmos to within 1 mm in patient 1, significant improvement in symmetry of the nasoethmoid complex in patient 2, and reconstruction of the zygomaticomaxillary complex location to within 1 mm in patient 3. CONCLUSION: Computer modeling and intraoperative navigation is a relatively new tool that can assist surgeons with reconstruction of the maxillofacial skeleton. © 2007 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved.

Periprosthetic fractures involving a total knee arthroplasty pose a challenging treatment problem with a prevalence of up to 2.5% in the literature (Instr Course Lect 2001;50:379-389). The supracondylar region of the femur is commonly involved, often with minimal available bone in contact with the components. The clinical challenges are particularly more complex in the case of a combined distal femoral and proximal tibial periprosthetic fracture. This injury is considered a "floating prosthesis" injury because of the complete separation of the prosthesis from the remaining skeleton. In this report, a floating prosthesis injury, in combination with a femoral shaft fracture, is treated with 2 locking plates using a minimally invasive technique, with limited blood loss, immediate pain relief after surgery, and successful healing of all fractures with minimal deformity.

BackgroundThe treatment of osteochondritis dissecans in the adult knee can be challenging. As part of our comprehensive treatment program, fresh osteochondral allografts have been used in the surgical management of osteochondritis dissecans of the femoral condyle.HypothesisFresh osteochondral allograft transplantation will provide a successful surgical treatment for osteochondritis dissecans of the femoral condyle.Study DesignCase series; Level of evidence, 4.MethodsSixty-six knees in 64 patients underwent fresh osteochondral allografting for the treatment of osteochondritis dissecans. Each patient was evaluated both preoperatively and postoperatively using an 18-point modified D'Aubigné and Postel scale. Subjective assessment was performed using a patient questionnaire. Radiographs were evaluated preoperatively and postoperatively.ResultsMean follow-up was 7.7 years (range, 2-22 years). There were 45 men and 19 women with a mean age of 28.6 years (range, 15-54 years). All patients had undergone previous surgery. Forty-one lesions involved the medial femoral condyle, and 25 involved the lateral femoral condyle. All were osteochondritis dissecans type 3 or 4. The mean allograft size was 7.5 cm2. One knee was lost to follow-up. Of the remaining 65 knees, 47 (72%) were rated good/excellent, 7 (11%) were rated fair, and 1 (2%) was rated poor. Ten patients (15%) underwent reoperation. The mean clinical score improved from 13.0 preoperatively to 16.4 postoperatively (P < .01). Fifty-nine of 64 patients completed questionnaires. Subjective knee function improved from a mean of 3.4 to 8.4 on a 10-point scale (P < .01).ConclusionWith greater than 70% good or excellent results, fresh osteochondral allograft transplantation is a successful surgical treatment for osteochondritis dissecans of the femoral condyle.

Acetabular retroversion has been proposed to contribute to the development of osteoarthritis of the hip. For the diagnosis of this condition, conventional AP pelvic radiographs may represent a reliable, easily available diagnostic modality as they can be obtained with a reproducible technique allowing the anterior and posterior acetabular rims to be visible for assessment. This study was designed to: (i) determine cranial, central, and caudal anatomic acetabular version (AV) from cadaveric specimens; (ii) establish the validity and reliability of the radiographic measurements of central acetabular anteversion; and (iii) determine the validity and reliability of the radiographic "cross-over-sign" to detect acetabular retroversion. Using 43 desiccated pelvises (86 acetabuli) the anatomic AVs were measured at three different transverse planes (cranially, centrally, and caudally). From these pelvises, standardized AP pelvic radiographs were obtained. To directly measure central AV, a modified radiographic method is introduced for the use of AP pelvic radiographs. The validity and reliability of this radiographic method and of the radiographic cross-over-sign to detect cranial acetabular retroversion were determined. The mean central and caudal anatomic AVs were approximately 20 degrees , and the mean cranial AV was 8 degrees . Cranial retroversion (AV < 0 degrees ) was present in 19 of 86 hips (22%). A linear correlation was found between the central and cranial AV. Below 10 degrees of central AV, all acetabuli were cranially retroverted. Between 10 degrees and 20 degrees , 30% of the acetabuli were cranially retroverted, and above 20 degrees , only 1 of 45 acetabuli was cranially retroverted. The radiographic measurement of the central AV (20.3 +/- 6.5 degrees ) correlated strongly with the anatomic AV (20.1 +/- 6.4 degrees ). The sensitivity of the cross-over-sign to detect a cranial acetabular anteversion of less than 4 degrees was 96%, its specificity 95%, and the positive predictive and negative predictive values 90% and 98%, respectively. Both the modified radiographic anteversion measurements and the cross-over-sign demonstrated substantial inter- and intraobserver reliability. Retroversion is almost exclusively a problem of the cranial acetabulum. The cranial AV is on average 12 degrees lower than the central AV, with the latter directly measurable from AP pelvic radiographs. A central AV of less than 10 degrees was associated with cranial retroversion. The presence of a positive cross-over-sign is a highly reliable indicator of cranial AV of

Fresh osteochondral allografting is a nonvascularized organ transplantation with a clinical use dating back to the early twentieth century. The procedure, in its current form, involves transplantation of a small segment of bone as a carrier with its overlying cartilage. As the bone is remodeled and revascularized by the recipient, the donor cartilage continues to function mechanically, produces matrix, and receives nutrition from the synovial fluid. The cartilage has traditionally been considered a so-called immunoprivileged tissue, avoiding the immune surveillance of the host presumably because of its paucity of vascular channels and its hypo-cellular matrix1. These qualities make fresh osteochondral allografting unique in the field of transplantation and preclude the need for systemic immunosuppression after this procedure. Although histologically normal articular cartilage has been reported in retrieved fresh osteochondral allografts, we know of no report that has definitively confirmed the specific survival of the donor cells for any length of time. Furthermore, the source of cells in retrieved transplants has not been confirmed as being from the donor or the recipient. The patient was informed that data concerning his case would be submitted for publication. Atwenty-two-year-old man with a large defect on the articular surface of the lateral femoral condyle of the knee underwent fresh osteochondral allografting from a female donor. He recovered well from the allograft procedure and had a relatively pain-free knee for the next twenty-five years. He presented to us with knee pain on the lateral side and tricompartmental arthritis predominantly in the lateral compartment (Fig. 1). A magnetic resonance imaging scan was acquired, and it demonstrated a tear of the posterior horn of the lateral meniscus with loss of the articular cartilage thickness along the posterior aspect of the lateral femoral condyle (Fig. 2). He ultimately requested total knee …

Traditional advanced imaging modalities such as CT and MRI are limited in their ability to perform accurate linear distance and angular measurements regardless of anatomical orientation. The construction of 3D models has been used to perform anthropometric analyses as well as in the reconstruction of rapid prototypes. We hypothesized that such measurements would be precise to within 2 mm or 2 degrees of measurements performed with a coordinate measurement machine (CMM). We also hypothesized that there would be a high degree of interobserver reliability with these measurements.Multiple aluminum screws were implanted in various positions in three foam pelvises which were subsequently scanned by CT and rendered as 3D models using a commercially available software package (Mimics). Linear and angular measurements were performed using a CMM machine, the software package, and a dial caliper or goniometer. The deviation of the measurements from the CMM data was compared using ANOVA. The interobserver reliability of both the manual and computer-generated measurements was calculated.The mean difference between the CMM distances and those measured manually and with the software was 2.12 +/- 1.20 mm and 1.57 +/- 1.05 mm, respectively. The mean difference between the CMM angular measurements and the angular measurements performed manually and with the software was 4.07 +/- 4.70 degrees and 1.62 +/- 1.32 degrees, respectively. In all cases, the manual measurements were significantly less accurate (p0.0001) and there was a high degree of interobserver reliability.Computer-generated measurements taken from three-dimensionally reconstructed models are more accurate than manual measurements and are within 2 mm and 2 degrees of measurements performed with a CMM. These measurements have high interobserver reliability.

Periprosthetic supracondylar fractures of the femur after total knee arthroplasty represent a devastating complication for the patient and a technical challenge for the surgeon. Treatment is often complicated by advanced patient age, retained cement, and accompanying osteoporosis. We present the case of a 54-year-old woman with a comminuted fracture of the distal femur just above a total knee prosthesis. She had a complex past medical history, including extensive coronary artery disease, morbid obesity, chronic osteoporosis, anemia, diabetes, and rheumatoid arthritis. She was a Jehovah's Witness and thus refused all blood products. Given her medical history, religious preferences, and fracture comminution, a spanning external fixator was used. She completed fracture union with an excellent clinical and radiographic result at 2 years.

The search for improved femoral fixation in cemented total hip arthroplasty is ongoing. Two design variables, surface finish and stem contour, were evaluated. Sixteen titanium femoral stems of one design were cemented into fiberglass femora. One half of the components had a polished surface and the rest had a roughened finish. Within each group, 4 stems had vertically oriented ribs on the proximal portion and 4 did not. Micromotion was measured in a stair climbing simulator with loading to a joint reaction force of 200 kg for 6 million cycles. Micromotion increased throughout the course of the experiment. Stems with a polished surface had significantly higher micromotion. Although stems with ribs had less micromotion compared with those without ribs, this difference was not statistically significant.

1-Introduction The Kopeh-Dagh as an inverted basin (Allen et al. 2003) is extended from the east of the Caspian Sea to NE Iran, north Afghanistan and Turkmenistan. Following the closure of palaeo-Tethys in the Middle Triassic and the opening of Neo-Tethys during the early to middle Jurassic, the Kopeh-Dagh basin formed during the early to middle Jurasic. Sedimentation took place continuously from the Jurassic through the Neogene time in the Kopeh-Dagh basin (Afshar-Harb 1979). The first geological study on these strata was done by Amiranian oil company from 1937 to 1938. Many biological and stratigraphical studies had been carried on later on this basin. Kalantari (1969), Seyed-Emami (1980), Seyed-Emami and Aryai (1981), Seyed-Emami et al. (1984, 1994, 1996), Immel et al (1997), Raisossadat and Mousavi-Harami (2000), Raisossadat (2004, 2006) and Mahanipour et al. (2011) are among those who studied the biostratigraphy and sedimentology of the Cretaceous strata of this basin. In this paper we report on palynological and paleoecological data from two mid-Cretaceous formations (Sarcheshmeh and Sanganeh) in Baghak section situated in eastern part of Kopeh-Dagh basin. 2-Materials and Methods Fifteen samples from the Sarcheshmeh and thirty five samples from Sanganeh formation were processed palynologically. The preparation method of Traverse, 2007 was used. Cold hydrochloric (20%) and hydrofluoric (50%) acids were used to dissolve carbonates and silicates. The residue was neutralized and centrifuged in ZnCl2 (specific gravity 1.9), then sieved at 15 um using a nylon mesh, and mounted on microscope slides using liquid Canada balsam. Three slides were made from each sample. The microscope slides were examined under a light microscope and the index dinocysts were photographed and presented in two plates. In order to study palynofacies, in each slide numbers of organic materials including phytoclasts, marine palynomorphs and non-structural organic materials were calculated in five purview and then the percent of each palynological elements were acquired. 3- Discussion, Results and Conclusion All of the 50 rock samples prepared have yielded dinofalgellate cysts. The assemblages recorded include such taxa as: Acomosphaera sp., Achomosphaera neptunii, Batioladinium sp., Bourkidinium granulatum, Cauca parva, Circulodinium sp., Circulodinium brevispinosum, Circulodinium distinctum, Cometodinium sp., Coronifera oceanica, Cribroperidinium sp., Cribroperidinium orthoceras, Florentinia sp., Florentinia cooksoniae, Florentinia mantelii, Glaphyrocysta sp., Gonyaulacysta sp., Gonyaulacysta polythyris, Hystrichosphaeridium sp., Kiokansium sp., Kiokansium polypes, Klithrosphaeridium sp., Muderongia sp., Muderongia tabulate, Odontochitina operculata, Oligosphaeridium complex, Oligosphaeridium poculum, Oligosphaeridium porosum, Oligosphaeridium totum, Paleoperidinium cretaceum, Prolixosphaeridium sp., Prolixosphaeridium parvispinium, Pseudoceratium sp., Pseudoceratium retusum, Pterodinium sp., Spiniferites sp., Spiniferites ramosus, Subtilisphaera sp., Systematophora sp., Tanyosphaeridium sp. (Plate 1-2). Based on the presence of the index dinoflagellate cyst, Odontochitina operculata throughout the entire section, it can be concluded that the first appearance of this species is before the first sample of the Sarcheshmeh Formation (sample 398) and therefore the identified dinoflagellate cysts are a part of the Odontochitina operculata Zone. This palynozone originally erected by Wilson (1984) for Aptian strata in New Zealand and Morgan (1980) suggest the age of Aptian for Odontochitina operculata Zone. The presence of species Gonyaulacysta polythyris, Circulodinium brevispinosum and Florentinia mantelii which are recorded from early Aptian strata in different part of the world such as Australia (Backhouse, 1988), France (Stover, 1996), south of Alpine Italia (Torricelli,2000) and south of Tanzania (Schrank & Mahmoud, 2002) in lower formation reveal the age of Late Barremian to early Aptian for the Sarcheshmeh Formation. The Upper formation contains species Cauca parva with middle Aptian-Lower Albian age (Stover, 1996) and Frorentinia cooksonia with middle Albian age (Williams 1993) found in different regions such as Libya (Uwins & Batten, 1988), United States (Hedlund & Norris, 1986) and west of Australia (Cookson & Eisenack, 1962). This species suggest the age of middle Aptian- middle Albian for the Sanganeh Formation. Statistical analyses of the three main groups of palynological elements (Phytoclasts, Marine palynomorphs and non-structural organic materials) lead to the recognition of five palynofacies in studied section. Studying the recognized palynofacies indicate that the sedimentation rate and oxygen level of the basin were variable but decreasing from Sarcheshmeh to Sanganeh Formation. Based on index dinoflagellates it can be concluded that depositional environment of the Sarcheshmeh and Sanganeh formations ranged from inner to outer neritic environment.

Twenty knees in 18 patients were treated (mean age, 42 years; range, 19-64 years) with fresh osteochondral allografting limited to the patellofemoral joint. The knees were analyzed retrospectively to determine the rate of successful outcomes. The trochlea and patella were treated in 12 patients and

Background: Isolated revision of an acetabular total hip component is associated with special problems related to the retention of the femoral component. We reviewed the intermediate-term results of a series of such operations with use of the Harris-Galante Porous acetabular component. Methods: We retrospectively studied the results of ninety-five isolated acetabular revisions, specifically focusing on sixty-three that had been followed for a minimum of sixty months (average, 130 months). Evaluation measures included the Harris hip score, radiographic analysis, complications, and prosthetic survival. Follow-up information was obtained with self-administered questionnaires, telephone contact, and/or clinical examination. The effects of a femoral component with a modular neck-head junction and of trochanteric osteotomy on the dislocation rate were evaluated. Results: Nine shells were rerevised: four because of recurrent dislocation, four because of aseptic loosening, and one because of dissociation of the liner. The survival rate with rerevision of the shell as the end point was 90.5% at 120 months. Pelvic osteolysis occurred in 4% of the cases. The dislocation rate for the sixty-three hips was 8%. When femoral component modularity was accounted for, the analysis of the dislocations revealed a significantly higher dislocation rate for the hips without a trochanteric osteotomy (p = 0.04). Eight arthroplasties were complicated by nerve palsies, seven of which resolved fully or nearly so. Conclusions: Isolated acetabular revision with use of the Harris-Galante Porous acetabular component was associated with a low rate of loosening, lysis, and rerevision of the shell at the time of intermediate-term follow-up. However, there was a high rate of complications, including trochanteric nonunion, dislocation, and nerve palsy. The performance of a trochanteric osteotomy was associated with a decreased rate of dislocation. Level of Evidence: Therapeutic study, Level IV (case series [no, or historical, control group]). See Instructions to Authors for a complete description of levels of evidence.

Tenotomy is a commonly encountered event in orthopaedic surgery. In 23 rabbit extensor digitorum longus (EDL) muscles, within 24 h after tenotomy, a marked drop in maximum force production occurred. This was not explainable based on architectural changes and histological examination using standard markers for muscle injury, i.e., haematoxylin and eosin morphology, developmental myosin heavy chain (MHC) immunolabeling, and quantitation of muscle fiber type percentage, area and distribution. The expression of neural cell adhesion molecule (NCAM), a glycoprotein expressed during muscle development was measured as a function of time in these muscles. NCAM expression was increased as early as one day after tenotomy with 2:2 � 1:2% of the fibers showing positive expression. This expression level increased significantly to 15:4 � 15:2% after 7 days and then subsided to 13:2 � 10:6% 21 days after tenotomy. Two-way analysis of variance demonstrated a significant effect of time and a significant time x tenotomy method interaction. These results suggest that tenotomy leads to possible changes in muscle–nerve connections and/or excitation–contraction (EC) coupling. 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.

Tenotomy is a commonly encountered clinical entity, whether traumatic or iatrogenic. This article reviews the response of skeletal muscle to tenotomy. The changes are subdivided into molecular, architectural, and functional categories. Architectural disruption of the muscle includes myofiber disorganization, central core necrosis, Z-line streaming, fibrosis of fibers and Golgi tendon organs, changes in sarcomere number, and alterations in the number of membrane particles. Molecular changes include transient changes in myosin heavy chain composition and expression of neural cell adhesion molecule (NCAM). Functionally, tenotomized muscle produces decreased maximum tetanic and twitch tension. Alterations in normal skeletal muscle structure and function are clinically applicable to the understanding of pathological states that follow tendon rupture and iatrogenic tenotomy.

Rabbit extensor digitorum longus (EDL) tendons were cut with the muscle active (active tenotomy, AT) or with the EDL at rest (passive tenotomy, PT). One, 7, and 21 days after tenotomy, contractile testing was performed. A second experiment was performed in which EDL tendons underwent PT and, after a 7-day delay, muscle-tendon units were restored to their original length. Maximum isometric tension dropped precipitously 1 day after either AT or PT to approximately 50% of normal and continued to decline by day 7. In contrast to PT, where peak tension (P(0)) decreased further by 21 days, after AT, P(0) partially recovered. Differences in muscle mass, cross-sectional area, fiber type, and sarcomere number did not explain the differential response. One day after length restoration of muscles, P(0) rapidly increased by approximately 40%. These observations have implications for understanding the outcome of muscle-tendon unit injury and surgical repair.

Educational Objectives As a result of reading this article, physicians should be able to: 1. Identify the etiology of femoroacetabular impingement. 2. Assess femoroacetabular impingement on physical examination. 3. Recognize femoroacetabular impingement on imaging studies. 4. Discuss modern techniques to effectively treat femoroacetabular impingement, both open and arthroscopic. Femoroacetabular impingement (FAI) is a recently proposed concept describing abnormal anatomic relationships within the hip joint that may lead to articular damage. Impingement is caused by bony deformities or spatial malorientation of the femoral head-neck junction and/or the acetabulum. These abnormalities lead to pathologic contact and shearing forces at the acetabular labrum and cartilage during physiological hip motion. There is an increasing body of evidence that these forces lead to cartilage wear and eventual osteoarthritis. Treatment options for FAI are evolving rapidly. Although the gold standard remains open hip dislocation, arthroscopic techniques have shown significant promise. It is possible that early recognition and treatment of subtle deformity about the hip may reduce the rate of hip osteoarthritis in the future. [ Orthopedics. 2015; 38(3):185–199.]

Cam morphology in femoroacetabular impingement has been implicated in the development of osteoarthritis. The alpha angle and femoral head/neck offset are widely used to determine femoral head asphericity. To our knowledge, no study has evaluated the alpha angle circumferentially using three-dimensional imaging in a population of healthy individuals of adolescent age.We sought to (1) determine normal values for the alpha angle in adolescents, (2) define the location along the neck with the highest alpha angle, and (3) determine normal femoral head and neck radii and femoral head/neck offset.Fifty CT scans from a database of scans obtained for reasons not related to hip pain were studied. The average age of the subjects was 15 years (range, 14-16 years). Alpha angle and femoral head/neck offset were measured circumferentially.The alpha angle averaged 40.66 ± 4.46 mm for males and 37.77 ± 5.65 mm for females. The alpha angle generally was highest between the 11:40 and 12:40 o'clock and between the 6:00 and 7:40 o'clock positions. The femoral head radius was 24.53 ± 1.74 mm for males and 21.94 ± 1.13 mm for females, and the femoral neck radius was 16.14 ± 2.32 mm for males and 13.82 ± 2.38 mm for females. The mean femoral head/neck offset was 8.39 ± 1.97 mm for males and 8.13 ± 2.27 mm for females.In this healthy population of 14- to 16-year-old subjects, the highest alpha angle was at the superior and inferior aspects of the heads rather than at the anterosuperior aspect. This information will provide benchmark values for distinction between normal and abnormal morphologic features of the femoral head.