کارآزمايى تصادفى شاهددار

v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} Normal 0 false false false false EN-US X-NONE AR-SA /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-language:FA;} کارآزمايى تصادفى شاهددار بسيارى اوقات راهنماى پزشکان در کار روزانه تأثيرات کارهاى بالينى آنها يا استادان آنها است اين تأثيرات و گمان‌ها - بخصوص هنگامى که در درسنامه‌ها گنجانده شده و اساتيد معتبر و دانشجويان هم مکرر به آن اشاره کرده باشند حالت موثّق و مرجع پيدا مى‌کند به‌طورى که بصورت واقعيات اثبات‌شده درمى‌آيند. همچنين بسيارى از تدابير و اقدامات مربوط به بهداشت عمومى براساس فوايد فرضى و بدون آن که آزمون‌هاى جدى روى آنها انجام گرفته باشد در برنامه‌ها وارد مى‌شوند. پيشينه پزشکى به وفور اين موضوع را نشان مى‌دهد. مثلاً قرن‌ها به‌طول انجاميد تا خون گرفتن و دادن مسهل‌هاى قوى به‌عنوان درمان توسط متخصصان پزشکى ترک شد. ولى عمدتاً در ۲۵ سال گذشته بوده که براى استفاده از فنون علمى به‌منظور ارزشيابى روش‌هاى پيشگيرى و درمان، کوشش شده است. پيشرفت مهم در اين زمينه ايجاد يک روش سنجش است که به نام کارآيى شاهددار اتفاقى شده (RCT) ناميده مى‌شود. در اين روش اعتبار درمان‌هايى مانند مايع درمانى خوراکي، قطع وريدهاى واريسي، لوزه‌برداري، بسترى کردن بيماران مبتلا به انفارکتوس ميوکارد، غربالگرى‌هاى چندمرحله‌اى که به گستردگى بکار گرفته مى‌شوند و تعيين سمّيت داروها و قابليت بکار گرفتن بسيارى روش‌هاى پيشگيرى و درمان، مورد ارزشيابى قرار مى‌گيرد. طرح RCT در شکل کارآزمايى شاهددار اتفاقى نشان داده شده است. در برنامه‌هاى بهداشتى يا درمانى جديد کارآزمايى‌هاى شاهددار اتفاقى روش درجه اول براى ارزشيابى است.    ◊ ”کوربودن“ کارآزمایی (Blinding)    ◊ انواع کارآزمایی‌های شاهددار اتفاقی‌شده    ◊ انواع کارآزمایی‌های شاهددار اتفاقی‌شده(۲)    ◊ بعضی طرح‌های RCT    ◊ مراحل اساسی اجرای RCT    ◊ مراحل اساسی اجرای(RCT(۲                           انواع کارآزمايى‌هاى شاهددار اتفاقى‌شده      ◊ ارزشیابی خدمات بهداشتی    ◊ کارآزمایی‌های بالینی    ◊ کارآزمایی‌های پیشگیری    ◊ کارآزمایی‌های عوامل خطر    ◊ کارآزمایی‌های مربوط به عوامل سببی    ◊ کارآزمایی‌های مربوط به قطع (ترک عادت)   کارآزمايى‌هاى بالينى کارآزمايى‌هاى باليني از بسيارى جهات براى ارزشيابى کارآمدى داروهاى جديد يا ديگر روش‌هاى درمانى مانند جراحي، فيزيوتراپي، پرتودرمانى و غيره مورد نظر بوده‌اند. نخستين‌بار کارآزمايى شاهددار اتفاقى در ارزشيابى داروهاى ضدسلى با موفقيت بکار رفت. در سى سال گذشته مفيد بودن کارآزمايى‌هاى بالينى به وضوح آشکار شده است. بعضى نمونه‌هاى جديد کارآزمايى‌هاى بالينى عبارتند از: ارزشيابى داروهاى بتابلوکر در کاهش مرگ‌ومير بيماريهاى قلبى عروقى در بيمارانى که از مرحله حاد سکته قلبى جان سالم به‌در مى‌برند، کارآزمايى‌هاى مربوط به درمان با فولات‌ها يا بصور تکميلى پيش از باردارى براى پيشگيرى از بروز مجدد نقايص نخاعي، کارآزماييظهاى مربوط به آسپيرين در کاهش مرگ‌ومير بيمارى‌هاى قلبى عروفى و بتاکاروتن در بروز سرطان، کارآمدى لوزه‌بردارى در جلوگيرى از بروز عفونت‌هاى بيمارى‌هاى قلبى عروقى و بتاکاروتن در بروز سرطان، کارآمدى لوزه‌بردارى در جلوگيرى از بروز عفونت‌هاى مکرر حلق، کارآزمايى شاهددار اتفاقى درباره عمل جراحى باى‌پاس عروق تاجى قلب براى جلوگيرى از سکته قلبى و... اين فهرست پايان ندارد. متأسفانه همه کارآزماى بالينى را نمى‌توان بصورت کور اجرا کرد. مثلاً درمورد کارآزماى‌هاى بالينى مربوط به لوزه‌بردارى يا آدنوئيدکتومى بدون اين که معلوم شود چه کسى لوزه‌بردارى مى‌کند و چه کسى نمى‌کند براى کور بودن راهى وجود ندارد و به اين دليل ارزش اين روش کارآزمايى نامطمئن مى‌شود. بسيارى از مشکلات اخلاقي، اجرايى و فنى در انجام کارآزمايى‌هاى بالينى وجود دارو، باوجود اين کارآزمايى‌هاى بالينى ابزار نيرومندى هستند و بايد پيش از معرفى هرنوع خدمت ا روش درمانى انجام شوند.   کارآزمايى‌هاى پيشگيرى پيشگيرى به‌طور کلى مترادف با پيشگيرى اوليه است و اصطلاح کارآزمايى حاکى از کارآزمايى‌هايى است که براى تدابير مربوط به پيشگيرى اوليه انجام مى‌شود. در اين کارآزماييظها پيشگيرى يا ازبين بردن بيمارى به‌طور تجربى فهمانده مى‌شوند. نوعى که از همه بيشتر بکار گرفته مى‌شود کارآزمايى‌هاى مربوط به واکسن‌ها و داروهاى مربوط به پيشگيرى دارويى است. اصول پايه طرح آزمايشى براى اين کارآزمايى‌ها هم کاربرد دارند. ممکن است لازم شود کارآزمايى براى گروه‌هايى از افراد انجام شود تا تک‌تک افراد. مثلاً در سال ۱۹۴۶ انجمن پژوهش پزشکى انگلستان کارآزمايى گسترده‌اى براى آزمون واکسن سياه‌طرفه ساخته شده توسط سه کارخانه را در دو کارآزمايى ميدانى جداگانه انجام داد. کودکان ۱۸-۶ ماهه‌اى که در کارآزمايى شرکت داده شدند بصورت تصادفى به گروه‌هاى شاهد و مطالعه تخصيص يافتند. واکسن بصورت سه تزريق ماهانه داده شد و کودکان با فاصله‌هاى يک‌ماهه ازنظر تعيين بروز سياه‌سرفه پيگيرى شدند. گروه مورد مطالعه شامل ۳۸۰۱ کودک واکسن‌زده بود که ۱۴۹ نفر آنها به سياه‌سرفه مبتلا شدند، گروه شاهد شامل ۳۷۵۷ کودک واکسن‌نزده بود که در ۶۸۶ نفر از آنها بيمارى بروز کرد و با اين ترتيب در گروه واکسن‌زده ميزان حمله بيمارى ۴۵/۱ در هزار و در گروه واکسن‌نزده ۷۲/۶ در هزار در هر ماه بود و اختلاف معنى‌دار آمارى وجود داشت. در تجزيه و تحليل کارآزمايى‌هاى پيشگيرى بايد نتيجه بصورت آشکار در موارد زير باشد: - فوايدى که از آن اقدام به جامعه مى‌رسد. - خطرات مربوطه. - هزينه خدمات بهداشتى ازنظر پول، نيروى انسانى و منابع مادي. چون در کارآزمايى‌هاى پيشگيرى عده بيشترى از افراد شرکت دارند وگاهى اوقات زمان بيشترى براى بدست آوردن نتايج لازم است، ممکن است مشکلات عملى بيشترى در سازماندهى و اجراى آنها بوجود آيد.   کارآزمايى‌هاى عوامل خطر يک نوع کارآزمايى پيشگيري، کارآزمايى عوامل خطر است که طى آن پژوهشگر براى قطع سلسله عوامل معمولى مربوط و بروز بيمارى در کسانى که داراى عامل خطر بروز هستند مداخله مى‌کند و اين کار غالباً شامل تغيير عوامل خطر است. مفهوم عامل خطر بُعد جديدى به پژوهش همه‌گيرى شناختى داده است. مثال؛ عوامل خطر عمده در بروز بيمارى سرخرگ‌هاى تاجى قلب افزايش کلسترول خون، سيگار کشيدن، پرفشارى خون و عادت به يک‌جا نشستن است و به‌ترتيب چهار امکان عمده در مداخله براى جلوگيرى از بيمارى مذکور عبارتند از: کاهش کلسترول سرم، ترک سيگار، کنترل فشارخون و افزايش حرکات و فعاليت بدنى بصورت منظم. کارآزمايى‌هاى مربوط به عامل خطر ممکن است تک‌عاملي يا چندعاملي باشند که هر دو روش مکمل يکديگر بوده و موردنياز هستند. سازمان بهداشت جهانى يک کارآزمايى مربوط به پيشگيرى اوليه از بيمارى‌هاى مربوط به رگ‌هاى تاجى قلب را با استفاده از کلوفيبرات به‌منظور کاستن از کلسترول سرم ترويج کرده است، زيرا افزايش کلسترول سرم به‌عنوان يک عامل خطر قابل توجه در بروز بيمارى پذيرفته شده است. اين مطالعه گسترده‌ترين کارآزمايى پيشگيرى است که تاکنون انجام شده و شامل ۱۵۰۰۰ مرد است که يک‌سوم آنها کلوفيبرات و دوسوم روغن زيتون (به‌عنوان گروه شاهد) دريافت مى‌داشتند. اين مطالعه در سه مرکز اروپايى (ادينبورگ، پراگ و بوداپست) اجرا شد. طرح مطالعه دوسو کور بود وتخصيص اتفاقى با موافقيت انجام شد. ميانگين مدت مشاهده ۶/۹ سال بود و نتيجه کارآزمايى نشان داد که در سکته‌هاى قلبى غيرکشنده کاهش قابل توجهى وجود دارد ولى متأسفانه در گروه درمان‌شده با کلوفيبرات نسبت به گروه شاهد ۲۵ درصد بيشتر مرگ ديده شد که احتمالاً به علت اثر سمى درازمدت دارو است. اين کارآزماى نشان مى‌دهد که روش اپيدميولوژيک مى‌تواند اثر حفاظتى براى بهداشت عمومى نسبت به اثرات نامطلوب احتمالى تجويز داروهاى مؤثر بصورت درازمدت داشته باشد. کارآزمايى‌هاى گسترده ديگر درباره بيمار ى عروق تاجى قلب عبارتند از: - مطالعه استانفورد در سه جامعه - طرح کارلياى شمالى در کشور فنلاند - مطالعه در شهر السو - کارآزمايى مداخله‌اى چند عامل خطر (MRFIT) در ايالات متحده آمريکا. انواع کارآزمايى‌هاى شاهددار اتفاقى‌شده(۲)   کارآزمايى‌هاى مربوط به قطع (ترک عادت) نوع ديگرى از کارآزمايى‌هاى پيشگيرى تجربيات مربوط به قطع است که در آن براى ارزشيابى پايان دادن به يک عادت (يا ازبين بردن يک عامل بيمارى‌زاى مشکوک) که به‌نظر مى‌آيد رابطهٔ علتى با بيمارى داشته باشد، کوشش مى‌شود. اگر اين اقدام کاهش چشمگير در بروز بيمارى داشته باشد به‌طور معمول فرضيه عليتى تقويت تقويت مى‌گردد. معروف‌ترين مثال اين کارآزمايى در سيگار کشيدن و سرطان ريه است. اگر در يک کارآزمايى شاهددار اتفاقى‌شده يک گروه از سيگارى‌ها به سيگارکشيدن ادامه دهند و گروهى ديگر آن را ترک نمايند با نشان دادن کاهش پيامد بروز سرطان ريه در گروه مورد بررسى فرضيه ارتباط عليتى به‌شدت تقويت مى‌شود.اخيراً يک کارآزمايى شاهددار اتفاقى‌شدهٔ گسترده براى مطالعه نقش ترک سيگار به‌عنوان پيشگيرى اوليه از بيمارى مرگ‌هاى تاجى قلب به‌اجرا درآمده است.   کارآزمايى‌هاى مربوط به عوامل سببى يکى از مقاصد اپيدميولوژى تجربى تأييد يا رد فرضيه‌هاى سبب‌شناختى است. معروف‌ترين مثال درمورد يک کارآزمايى عامل بيمارى‌زا در رابطه با سبب‌شناختى فيبروپلازى پشت عدسى چشم (Retrolental Fibroplasis-RLF) است. فيبروپلازى پشت عدسى چشم به‌عنوان يک عامل کورى تا پيش از سال ۱۹۳۸ وجود نداشت. اين عارضه در اصل توسط T.L.Terry چشم‌پزشک (در شهر بوستون) در سال ۱۹۴۲ و Jater در بسيارى ديگر از کشورها غير ايالات متحده، مشاهده و گزارش شد.RLF به‌عنوان عامل منجر به کورى در مطالعات توصيفى شناسايى شد. اين مطالعات نشان داد که در آغاز حدود سالهاى ۴۱-۱۹۴۰ ميزان بروز آن را به‌اندازه هشدار دهنده نشان داده (شکل بروسى RLF در نيويورک در سالهاى ۱۹۳۸ تا ۱۹۵۶ ) شده، اين بيمارى قبلاً ناشناخته در کودکان نارس بروز مى‌کرد. مطالعات تحليلى ارتباط نزديک آن را با تجويز اکسيژن در کودکان نارس نشان داد، و يک کارآزمايى شاهددار اتفاقى شده گسترده توسط Kinsey و Hemphill در هجده بيمارستان ايالات متحده به‌اجرا درآمد که طى آن کودکان نارس داراى وزن هنگام تولد ۱۵۰۰ گرم و کمتر به دو گروه آزمايشى و شاهد تخصيص يافتند. در گروه آزمايشى همه کودکان به مدت ۲۸ روز ۵۰ درصد اکسيژن درمانى شدند در حالى که در گروه شاهد (که زير چادر اکسيژن بودند) اکسيژن فقط در مواردى که ازلحاظ بالينى فوريت داشت تجويز شد، بعداً معلوم شد همه کودکان گروه چادر اکسيژن که مبتلا به RLF شدند آنهايى بوده‌اند که قدرى اکسيژن دريافت داشته‌اند. دربين بچه‌هايى که اصلاً اکسيژن نگرفته بودند هيچ مورد بيمارى ديده نشد و اين موضوع فرضيه سبب‌شناختى را تأييد مى‌کرد.افزايش و کاهش چشم‌گير RLF را در شکل شماره ۱۱ مى‌توان ديد. بايد توجه نمود که موارد ابتلا به RLF در سالهاى ۵۳-۱۹۵۲ به اوج خود رسيد و تنزل سريع نمودار پس از سال ۱۹۵۳ نتيجه کاهش مصرف اکسيژن است. موضوع RLF يکى از مشکلاتى را که به علت پيشرفت‌هاى علمى يا تکنولوژيک ايجاد مى‌شود، نشان مى‌دهد. چون بسيارى از بيمارى‌ها کشنده، ناتوان کننده و يا ناپسند هستند، آزمايش‌هاى انسانى به‌منظور تأييد فرضيه‌هاى سبب‌شناسى بندرت امکان‌پذير است.   ارزشيابى خدمات بهداشتى کارآزمايى‌هاى شاهددار اتفاقى براى سنجش کارآيى و کارآمدى خدمات بهداشتى هم‌دامنه دارند غالباً بايد بين سياست‌هاى متفاوت بهداشتى نوعى انتخاب به‌عمل آيد. ضرورت انتخاب از اين واقعيت ناشى مى‌شود که منابع محدود است و براى اجراى تعداد زيادى فعاليت‌هايى که در رفاه جامعه سهمى دارند بايد اولويت تعيين شود. يک نمونه عالياز اينگونه ارزشيابى‌ها کارآزمايى‌هاى کنترل‌شده در پيشگيرى دارويى سل در هندوستان است، در اين کارآزمايى‌ها نشان داده شد که درمان سل ريوي در خانه هم به‌اندازه درمان در بيمارستان يا آسايشگاه مؤثر و بسيار باصرفه‌تر است. نتايج بررسى مورد پذيرش بين‌المللى قرار گرفت و سبب عصر جديد درمان سل به نام درمان سل در خانه شد.اخيراً غربالگرى چندمرحله‌اى که در بعضى کشورها مقبوليت فراوان يافته در جنوب شرقى هندوستان توسط RCT مورد ارزشيابى قرار گرفت و نتيجه مطالعه منجر به چشم‌پوشى کردن از صرف منابع بسيار براى برقرارى يک برنامه غربالگرى چندمرحله‌اى در بريتانيا شد. مثال ديگر در رابطه با مطالعاتى است که نشان دادند بسيارى از مراقبت‌هاى بهداشتى را که به‌طور سنتى توسط پزشکان انجام مى‌شود توسط پرستاران يا ديگر کارکنان پيراپزشکى هم مى‌توان انجام داد و با اين ترتيب از وقت پزشکان صرفه‌جويى نمود.اينگونه مطالعات را پژوهش در خدمات بهداشتي هم مى‌نامند.     بررسي تاًثير ريشه كني هليكو باكتر پيلوري در پسرفت ضايعات پيش سرطاني معده در خويشاوندان درجه يك بيماران مبتلا به آدنو كارسينوماي معده با روش كارآزمايي باليني دوسوكور تصادفي شاهد دار با پيگيري دراز مدت ، يك تحقيق چند مركزي. کارآزمایی شاهددار تصادفی یا RCT) Randomised Controlled Trials)تحقیقی است که طی آن افراد به طور تصادفی جهت دریافت یک یا چند مداخله بالینی اختصاص یافته‌اند RCT .معمولا در جستجوی اندازه‌گیری یا مقایسه وقایع مختلفی که در شرکت کنندگان بعد از دریافت مداخلات ایجاد می‌گردد و یا از بین می‌رود, می‌باشند .   ) multicenter trials كارآزمايي‌هاي چند مرکزي( يك مطالعه چند مرکزي مزاياي فراواني نسبت به مطالعات تك مرکزي دارد. براي مثال ورود تعداد بيشتري از بيماران را در مدت زمان كوتاه‌تري به مطالعه ميسر مي‌سازد. نتايج آن تعميم‌پذيرتر و همزمان براي يك جمعيت بزرگ‌تر مي‌باشد. به كارگيري چنين معاملاتي در كارآزمايي‌هايي كه بيماران با تظاهرات يا بيماري‌هاي نادراند قابل تأمل مي‌باشد.    An open-label trial or open trial is a type of clinical trial in which both the researchers and participants know which treatment is being administered.[1] [2] This contrasts with single blind and double blind experimental designs, where participants are not aware of what treatment they are receiving (researchers are also unaware in a double blind trial). Open-label trials may be appropriate for comparing two very similar treatments to determine which is most effective. An open-label trial may be unavoidable under some circumstances, such as comparing the effectiveness of a medication to intensive physical therapy sessions. An open-label trial may still be randomized. Open-label trials may also be uncontrolled, with all participants receiving the same treatment. باز برچسب محاکمه یا محاکمه باز از نوع کارآزمایی بالینی است که در آن هر دو محققان و شرکت کنندگان می دانند که درمان تجویز شده است. [1] [2] این در تضاد با تک کور و طرح دو سو کور تجربی، که در آن شرکت کنندگان آگاهچه درمان آنها دریافت می کنند (محققان نیز غافل در یک کارآزمایی دو سو کور). برچسب باز آزمایشات ممکن است مناسب برای مقایسه دو بسیار شبیه به درمان مشخص است که موثر ترین است. برچسب باز دادگاه تحت برخی شرایط، ممکن است غیر قابل اجتناب مانند مقایسه یک دارو به فشرده جلسات درمان فیزیکی است. برچسب باز آزمایش، هنوز هم ممکن است تصادفی باشد. برچسب باز آزمایشات نیز ممکن است غیر قابل کنترل می شود، با تمام شرکت کنندگان دریافت درمان همان است.         Page Options ·         Print This Page More NCI Dictionaries ·         NCI Drug Dictionary ·         Glossary of Statistical Terms ·         NCI Dictionary of Genetics Terms ·         Terminology Resources Widget ·         NCI Dictionary Widget Tool for websites to let users look up cancer-related terms The search textbox has an autosuggest feature. When you enter three or more characters, a list of up to 10 suggestions will popup under the textbox. Use the arrow keys to move through the suggestions. To select a suggestion, hit the enter key. Using the escape key closes the listbox and puts you back at the textbox. The radio buttons allow you to toggle between having all search items start with or contain the text you entered in the search box.   open label study    (OH-pen LAY-bel STUH-dee)   A type of study in which both the health providers and the patients are aware of the drug or treatment being given. ·    We Can Answer Your Questions ·    1-800-4-CANCER ·    LiveHelp Online Chat     Background Fractures around implants pose unique fixation challenges. The original placement of the implant may predispose to later fracture, the long-term presence of the device may change the structure of the bone and increase susceptibility to fracture, and the implant itself may interfere with healing or the placement of other fixation devices. The number of implants in the femur is increasing as the population ages, and the indications for joint replacement and fixation increase. Fractures around joint replacement prostheses are commonly called periprosthetic fractures, while fractures around plates, rods, or prostheses can be more generally termed peri-implant fractures. As more peri-implant fractures occur, the orthopedic surgeon needs to learn methods to manage the specific problems involved. An image depicting a fracture around an implant can be seen below. Distal femur fracture during hip arthroplasty.     Periprosthetic Acetabular Fracture (THA  HSS J. 2007 September; 3(2): 190–197. Published online 2007 April 25. doi:  10.1007/s11420-007-9045-4 PMCID: PMC2504263 Periprosthetic Fractures of the Femur After Hip Arthroplasty: An Analysis of 99 Patients Keith Holley, MD,1 Jonathan Zelken, BA,2 Douglas Padgett, MD,2 George Chimento, MD,3 Andrew Yun, MD,4 andRobert Buly, MD2 Author information ► Copyright and License information ► Go to: Abstract The medical records and radiographs of 99 patients treated for a periprosthetic femur fracture after total hip arthroplasty over a 17-year period at a single institution were prospectively reviewed. Fractures were classified according to the Vancouver system and stratified as to treatment method. Sixty-six patients had complete records available and a minimum of 12 months follow-up. Overall, 86% of the patients achieved fracture union. The success rate of cemented revision in the B2 and B3 groups was 84%, whereas cement-less revision was 86% successful. The complication rate of surgical treatment was 29%. Fracture union with a stable implant was possible in the majority of cases. Our results support the use of the Vancouver classification as a treatment algorithm. Key words: periprosthetic fracture, THA, revision THA, ORIF, Vancouver classification Go to: Introduction Periprosthetic fractures of the femur after total hip arthroplasty (THA) represent a difficult treatment challenge. The results of management of periprosthetic fractures have varied greatly due to factors such as bone quality, fracture pattern and method of treatment including nonoperative measures, reduction-fixation, or revision surgery. These treatments have historically been fraught with a high incidence of complications, treatment failures, and compromised outcomes [1–13]. Despite these problems, surgical treatment has become the standard in treating the majority of periprosthetic femur fracture [14]. The true incidence of periprosthetic fractures is uncertain, with estimates ranging from 0.1 to 2.1% [6, 14,15]. In data from the Mayo Clinic Joint Registry, the incidence of periprosthetic fracture after primary THA was 1.1%, and it was 4.0% after revision THA [14, 16]. In one series, periprosthetic fracture after THA was the second leading cause of revision, after aseptic loosening [14]. With the increasing prevalence of THA and revision THA in the USA, along with an aging population, the absolute number of periprosthetic fractures can be expected to increase as well. Currently, the treatment of periprosthetic fractures has included nonoperative measures, open reduction internal fixation (ORIF) as well as revision. Due to the number of confounding variables regarding treatment, Duncan and Masri developed a system of classification of periprosthetic fractures according to location, implant stability, and degree of bone loss (Vancouver Classification [17]) and advocated an algorithm towards treatment. The purpose of this investigation was to examine our experience with the treatment of periprosthetic fractures of the hip over a 17-year period and to corroborate the recommendations of the Vancouver group. Go to: Materials and methods A retrospective review of all periprosthetic femur fractures after THA treated at our institution from 1984 to 2001 was performed. All surgical procedures were performed at a single institution, but these were performed by a total of 12 different surgeons. The medical records of all patients were reviewed for such factors as patient age, sex, type of treatment, operative findings, number and type of complications associated with the fracture and its treatment, and condition of the patient before and after surgery. Radiographs were reviewed to ascertain fracture type, type of prosthesis (cemented or noncemented), the presence of preexisting osteopenia, evidence of healing, and condition of the prosthesis at latest follow-up. Fractures were classified according to the Vancouver classification of Duncan and Masri [17, 18]. This classification system, described in previous publications, is now widely accepted in the classification and treatment of periprosthetic fractures of the femur. Type A fractures are fractures of the greater or lesser trochanters. Type B fractures involve the femoral diaphysis and/or metaphysis around the femoral stem and are subdivided into three types. In type B1 fractures, the stem is stable, B2 fractures are associated with a loose stem, and B3 fractures are associated with a loose stem and significant bone loss. Type C fractures are well distal to the tip of the femoral stem. The treatment was classified as (1) nonoperative; (2) reduction and fixation employing interfragmentary or cerclage fixation, plate fixation (including flat plates, plate-clamp devices, and plates with fixed-angle devices), or plate fixation with use of cortical strut grafts; or (3) revision surgery using either uncemented in-growth stem or cemented stem revision. In cases of femoral stem revision, cables were commonly used for fixation, but supplemental plates were not used. The use and type of bone graft material was also recorded. The stability of the femoral prosthesis was judged from the radiographs at final follow-up. Criteria for judging the stability of cement-less stems were those described by Engh et al. [19] and include the presence of spots welds, lack of radiolucent lines, absence of pedestal formation, absence of calcar remodeling, and no evidence of migration. For cemented femoral components, the criteria of Harris et al. [20] were utilized. Stems that had migrated on serial radiographs were considered as definitely loose, stems with a continuous radiolucent zone at the bone–cement interface on either anteroposterior or lateral radiographs were considered as probably loose, and stems with a radiolucent zone occupying between 50 and 100% of the bone–cement interface were considered as possibly loose. Patients who had not been recently evaluated were asked to make an office visit for routine clinical evaluation and radiographs. Patients who declined to return for follow-up did so for a variety of reasons, which commonly included remote geographic location, advanced age, and difficulty with travel. Patients who could not come to the hospital for follow-up were interviewed over the telephone. The study had the approval of the Institutional Review Board. Patients who had less than 12 months of follow-up and could not be contacted or had died were excluded. In this study, the main outcome measure was either fracture union or implant survival. Treatment within each fracture type was stratified and chi-square analysis was performed to determine the level of statistical significance in regards to treatment outcome at the 95% confidence level. Go to: Results There were 99 periprosthetic femur fractures after THA treated during this time period. These consisted of 32 males and 67 females with an average age of 68.1 years. Demographic data are listed in Table 1. Table 1. Patient demographics Twenty-five patients had died with less than 12 months of follow-up. These by and large tended to be elderly patients, frequently with multiple medical comorbidities. An additional eight patients with less than 12 months of follow-up could not be contacted. All of these eight patients were two or more years postsurgery at the time of this review and were lost to follow-up despite all attempts to locate and contact them. These 33 patients were therefore excluded from the outcome analysis. The study group for analysis of treatment outcomes and complications therefore comprised 66 patients with a minimum of 12 months of follow-up. There were 21 males and 45 females. The average age was 64.0 years, with a range of 17 to 96 years. The right hip was involved in 39 patients and the left hip in 27 patients. The diagnoses leading to hip arthroplasty were osteoarthritis in 36 patients, rheumatoid arthritis (RA) or juvenile rheumatoid arthritis (JRA) in 16 patients, posttraumatic arthrosis in eight patients, osteonecrosis in five patients, and developmental dysplasia of the hip in one patient. The periprosthetic fracture involved a primary THA in 33 cases, a revision THA in 29 cases, and a primary hemiarthroplasty in four cases. The Vancouver classification of this group of fractures was 2 type A, 25 type B1, 20 type B2, 9 type B3, and 10 type C. The patients had an average of 2.2 previous surgeries on the involved hip prior to the periprosthetic fracture. The average time period between the original hip replacement procedure and the periprosthetic fracture was 109 months. The period of follow-up from the time of the periprosthetic fracture ranged from 12 to 180 months, with an average of 62 months. Type A fractures (trochanteric fracture) There were two patients with type A fractures of the greater trochanter. Both of these patients underwent operative treatment consisting of ORIF utilizing a plate/clamp device with implant retention. The fracture united in both cases (100% union). One patient sustained a dislocation 8 months after the fracture surgery, which was treated with closed reduction. The second patient underwent elective hardware removal at 1 year postoperatively for lateral trochanteric pain but had no other complications. Type B1 fractures (fracture with stable implant) The type B1 subgroup consisted of 25 patients with 7 uncemented and 18 cemented stems. Data for this group are listed in Table 2. Of these, four were treated nonoperatively and 20 were treated with ORIF: three with cerclage wiring, nine ORIF with a plate device, eight ORIF with a plate device plus strut allograft, and one underwent revision with an uncemented femoral stem. At latest follow-up, 18 patients (72%) achieved union of their fracture after the initial treatment, three patients (12%) required one or more further procedures to achieve union, and four patients (16%) had an established nonunion. Three patients who sustained a second periprosthetic fracture of the same femur had union or early healing at latest follow-up. Overall, 22 (88%) patients had a stable implant at final follow-up and three patients had implants that were considered to be loose. Table 2. Type B1 fractures There were four treatment failures: two in the nonoperative group (two of four), one with ORIF with plate alone (one of nine), and one ORIF with plate and allograft strut (one of eight). Two of the four patients initially treated nonoperatively subsequently failed to heal the fracture and were considered treatment failures. Both of these patients had an established nonunion at latest follow-up despite subsequent revision of the femoral component. At final follow-up, 18 of 20 patients treated with ORIF achieved union (90%). Of the nine patients treated with ORIF and a plate device, six achieved fracture union after the primary treatment, two required reoperation for delayed union, and one fracture was a nonunion. Two of these six patients sustained a second periprosthetic fracture between 1 and 3 years later, both of which were healing at latest follow-up after repeat surgical treatment. Of eight patients who had ORIF with a plate device plus a strut allograft, seven had primary fracture union and one went on to an established nonunion. One patient with a B1 fracture around an S-ROM (Depuy Orthopaedics, Warsaw, IN, USA) stem underwent revision to a longer S-ROM stem with retention of the ingrown sleeve component, as well as stabilization with a strut allograft and cables. This patient healed successfully without complications and had a stable component at latest follow-up. Union rates by treatment type were as follows: nonoperative treatment 2/4 (50%) and ORIF treatment 18/20 (90%). There were nine complications associated with treatment in five patients. These included one nonfatal pulmonary embolism (PE), three soft-tissue infections, one deep joint-space infection, two hematomas requiring surgical drainage, and two patients with one or more subsequent dislocations. All three soft tissue infections were treated successfully with surgical irrigation and debridement plus antibiotics, and all three subsequently had successful union of their fractures. The deep joint space infection was associated with nonunion of the fracture and was treated with long-term antibiotic suppression due to a compromised medical condition and limited global function. Type B2 fractures (fracture associated with loose implant) This subgroup consisted of 20 patients with 2 uncemented and 18 cemented stems. Two patients underwent ORIF of the fracture with a plate, 13 underwent treatment with cemented revision of the femoral stem, and 5 underwent uncemented revision of the femoral stem. Data are listed in Table 3. Overall, 17 patients achieved union after the primary treatment (85%), two patients’ fractures united after a second procedure, and one patient had an established nonunion at latest follow-up, for a 95% success rate. Three patients in this group sustained a second periprosthetic fracture and required further surgical treatment. All three of these patients had demonstrated union of the second fracture at latest follow-up. Seventeen patients (85%) had a stable implant at latest follow-up. Three patients had a loose femoral stem, one of which was associated with an established nonunion, one of which was awaiting revision, and one in which the patient had died. Table 3. Type B2 fractures Both of the patients treated by ORIF with a plate and morcelized bone graft (100% union) subsequently healed despite the presence of a loose femoral stem. One of these patients had no further surgery and still had a loose implant at latest follow-up. The other sustained a second periprosthetic fracture 4 years later, which was treated with a cemented femoral revision. This patient had a healed fracture and a stable implant at latest follow-up. Of the 13 patients who had a cemented femoral revision, 11 healed without another procedure (85%), one healed after placement of additional internal fracture fixation, and one had an established nonunion despite having undergone a second revision procedure to an uncemented femoral component with placement of a plate and allograft struts. Of the five patients treated with an uncemented femoral revision, four achieved primary fracture union (80%) and one required a repeat revision of the femoral component before healing. There was no difference in union rates between the ORIF group, the cemented revision group, or the uncemented revision groups (p=0.53). There were a total of seven complications associated with treatment, which occurred in six patients. They were one postoperative cardiac arrhythmia, one nonfatal PE, one superficial wound infection requiring irrigation and debridement, one septic joint requiring two-stage implant exchange, two dislocations treated nonoperatively, and one postoperative hematoma requiring surgical drainage. Type B3 fractures (fracture, loose stem, and bone loss) There were nine patients with type B3 fractures around one uncemented and eight cemented stems. Data are listed in Table 4. Six patients were treated with cemented femoral revision, two patients with uncemented femoral revision, and one patient with ORIF. Seven patients achieved fracture union after the primary treatment (78%), one patient’s fracture united after further surgery, and one patient’s fracture never healed despite multiple surgeries. All patients in this group were considered to have stable implants at latest follow-up. Table 4. Type B3 fractures Five of six patients who were treated with a cemented femoral revision (three with strut allografting, two without) went on to fracture union (83%). One patient with RA who was initially treated with a cemented femoral revision had multiple subsequent surgeries for infection, refracture, and nonunion was ultimately converted to a total femur replacement. Two patients treated with uncemented revision subsequently achieved union without further fracture treatment. One woman with JRA and severe bone loss was initially treated by ORIF with a plate, cables, and morcelized allograft. She developed a deep space infection and delayed union of the fracture. After hardware removal and treatment of the infection, she was successfully treated with an uncemented femoral revision. The results demonstrated higher union rates in the revision group vs. the ORIF group (p=0.047) Only three patients in this group did not have a postoperative complication associated with the fracture treatment. Of the other six patients, four had one or more dislocations, and three had deep infections requiring implant removal and further revision procedures. Type C fractures (fracture below implant) Data for type C fractures are listed in Table 5. There were ten patients in this subgroup with two uncemented and eight cemented stems. Two patients were treated initially with nonoperative treatment, six were treated by ORIF with a plate device, and two were treated by ORIF with a plate plus strut allograft. Of the two patients that were initially treated with traction followed by a cast or brace, one went on to heal without complications (50%) but the other patient developed a nonunion, which was subsequently treated with ORIF plus bone grafting. This surgery was complicated by hematoma formation and recurrent infection, and the patient ultimately required a transfemoral amputation. Eight patients underwent ORIF with or without strut grafting. Of these, four achieved primary fracture union (50%) and two required repeat ORIF but were united at latest follow-up. The other two patients went on to a nonunion. One patient who required multiple surgical procedures for recurrent joint sepsis, osteomyelitis, and nonunion was finally treated with a total femur replacement. The other patient had an established nonunion despite a second ORIF and a subsequent revision to a long-stem S-ROM. Eight out of the ten (80%) had a stable femoral implant at the latest follow-up. Complications associated with treatment in this group consisted of the two patients with recurrent infections mentioned above. There was no statistical difference between groups regarding union whether nonoperative or ORIF was the treatment of choice (p=0.49). Table 5. Type C fractures Go to: Discussion Although the overall rate of periprosthetic femur fractures associated with THA is unknown, it appears to be increasing [21, 22]. Estimates in the literature range from 0.1 to 2.1% for postoperative fractures and from 0.3 to 5.4% for intraoperative fractures [14]. Postoperative fracture rates are generally higher for revision THA compared to primary THA, whereas intraoperative rates are generally higher for uncemented THA compared to cemented THA. The treatment of periprosthetic femur fractures after THA has historically been associated with a high rate of treatment failures, complications, and unsatisfactory outcomes. Difficulty arises in comparison of various results in the literature due to differences in length of patient follow-up, patient demographics, types of implants used, the number of revision arthroplasties, the types of operative techniques employed, and variable outcome measures utilized. To date, no prospective randomized trial studying treatment interventions has been performed. It has been the work of Duncan and Masri [17] that has clearly aided in the classification and recommendation for treatment of these complex fractures. According to these authors, treatment is guided by the classification system, with type A fractures generally being treated nonoperatively or with cerclage fixation. Type B1 fractures can be treated by ORIF with plate devices and or the use of cortical strut grafts. Type B2 fractures usually require revision to a long-stem femoral component, with or without additional extramedullary fracture fixation. Type B3 fractures, in addition to revision of the femoral stem, generally require the use of significant allograft in an attempt to reestablish bone stock. Type C fractures can usually be treated by ORIF with standard plate systems or fixed angle plate devices. While these recommendations occurred after the onset of our study, our results appear to be consistent with what these authors have found. The results of this series are similar to those from previous reports and reflect the difficulty in treating periprosthetic fractures of the femur after THA. In this study, 74% of patients achieved fracture union after the primary treatment, whereas another 12% united the fracture after undergoing further surgical treatment, for a final fracture union rate of 86%. Complications relating to surgical treatment occurred in 19 patients, for a rate of 29% confirming the complicated nature of this type of surgery including several patients with multiple complications. There are several limitations inherent to this type of review including different biases towards treatment over the study time period and the limited number of study patients within some groups. However, clearly some trends are worth noting. While not statistically significant, among the type B1 fractures, those treated with ORIF and the use of a plate plus a cortical strut graft had a higher healing rate (seven of eight, 88%) than those treated with a plate device alone (six of nine, 67%), although the numbers are small in this subgroup. There has been support in the recent literature for use of onlay allograft cortical struts [4, 23], as well as animal studies investigating the use of osteogenic proteins to enhance strut allograft healing [24]. In the B2 group the success rate with cemented revision (11 of 13, 85%) was equivalent to that of uncemented revision (four of five, 80%). Not surprisingly, our type B3 fractures were associated with the highest complication rates (66%) in our series, as might be expected given the difficulty of surgical reconstruction of many of these fractures. Cemented femoral revision was surprisingly successful in this subgroup, with five of six patients (83%) healing and having a stable femoral component at latest follow-up. Of note, while both patients in whom ORIF was performed gained union, the implants were still both loose at follow-up, making the patients potentially at risk for fracture. Currently, we would recommend revision of the implant. In the C group of patients, it was interesting to note that union was difficult to obtain regardless of treatment (50%). Clearly, patient factors such as osteopenia and the effect of stress shielding may play a role in getting these fractures to unite. Consideration of adjuvant bone grafting as well as potential use of bone enhancing agents should be given at the time of surgery. A clear trend was that patients with RA or JRA fared much worse than the overall group. In addition to having compromised immune systems due to the effects of various disease-modifying agents, these patients also frequently had poor bone stock. Of 16 patients, only eight successfully healed after initial treatment. Six fractures ultimately went on to become nonunions, with two patients being converted to total femur replacement due to recurrent infection, nonhealing, and bone loss. Total femur replacement following periprosthetic fractures in RA patients has also been previously reported in the literature [25]. Three patients sustained a refracture and 6 of the 16 (38%) had one or more infections. These high complication rates highlight the risk to RA and JRA patients whose underlying disease can compromise treatment outcomes. Recently, authors at the Mayo clinic reported the results of revision arthroplasty for 118 hips with Vancouver type-B fractures [11]. The femoral implants used in this series included cemented stems, proximally porous coated uncemented stems, extensively coated stems, and allograft-prosthetic composites. Overall, Kaplan–Meier analysis showed a 5-year survival rate of 90% and a 10-year rate of 79.2%. They concluded that the best results were seen when an uncemented and extensively porous coated stem was used. There have also been recent reports demonstrating good results with the use of Wagner-type fluted tapered stems for the treatment of Vancouver type-B fractures [12, 13]. The patient numbers were small in these two studies, however. Beals and Tower [1] reported the results of 93 periprosthetic fractures treated at numerous facilities by multiple surgeons. Overall, outcomes were considered excellent in 32% of cases, good in 16%, and poor in 52%. Most fractures except trochanteric fractures had a poor result with nonoperative treatment. They also found that the results of ingrowth revision were superior to those for cemented revision for all fracture types. The complication rates were 41% relating to the fracture and 33% relating to the arthroplasty. Sledge and Abiri [2] reported on seven patients with Vancouver B2 fractures treated in a standardized manner with removal of the implant, cerclage wiring of the fracture with allograft struts, and implantation of a long, uncemented stem. A modular, proximally loading implant was used in three cases, and a curved, fully porous-coated stem was used in four cases. At 33 months average follow-up, they reported no failures, no refractures, and an average Harris hip score of 83. All patients except one returned to their preoperative ambulatory status. They did not comment on complications. Enthusiasm for operative treatment of complex periprosthetic fracture gained popularity based upon the work of Mont and Maar [26], whose meta-analysis of 26 published reports looked at periprosthetic fractures in 487 patients. While comparisons are difficult due to a lack of uniformity in fracture classification and reporting of outcomes, they found the most satisfactory outcomes for type 2, 3, and 4 fractures (around the tip of the stem) with cerclage fixation or long-stem revision. Screw/plate fixation and nonoperative treatment with traction generally lead to unsatisfactory outcomes. Highly comminuted type 5 fractures appeared to be best treated with long-stem revision. Our results demonstrate good success rates in treating the majority of periprosthetic femur fractures. However, surgeons should be alerted to the high rate of complications in this group. When presented with a periprosthetic fracture, we feel that the Vancouver classification system provides excellent stratification and uniform terminology. In addition, our data support the treatment algorithm recommended by the Vancouver group. While one of the limitations of this study includes small numbers of subjects, especially in the nonoperative treatment groups, we believe that depth of analysis of the surgical group provides ample support for our conclusions. Future studies employing prospective randomized trials should be conducted in an attempt to confirm classification systems and outcome measures. However, based upon our data, we recommend the use of the Vancouver classification system and treatment algorithm for these difficult fractures. Go to: Footnotes No institutional or private financial support was available for this study. The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Navy, the Department of Defense, or the United States Government. Go to: References 1. Beals RK, Tower SS (1996) Periprosthetic fractures of the femur. An analysis of 93 fractures. Clin Orthop 327:238–246. [PubMed] 2. Sledge JB, Abiri A (2002) An algorithm for the treatment of Vancouver type B2 periprosthetic proximal femoral fractures. J Arthroplasty 17:887–892. [PubMed] 3. Ahuja S, Chatterji S (2002) The Mennen femoral plate for fixation of periprosthetic femoral fractures following hip arthroplasty. Injury 33(1):47–50. [PubMed] 4. Brady OH, Garbuz DS, Masri BA, Duncan CP (1999) The treatment of periprosthetic fractures of the femur using cortical onlay allograft struts. Orthop Clin North Am 30(2):249–257. [PubMed] 5. Eingartner C, Volkmann R, Putz M, Weller S (1997) Uncemented revision stem for biological osteosynthesis in periprosthetic femoral fractures. Int Orthop 21(1):25–29. [PubMed] 6. Lewallen DG, Berry DJ (1998) Periprosthetic fracture of the femur after total hip arthroplasty: treatment and results to date. Instr Course Lect 47:243–249. [PubMed] 7. Tadross TS, Nanu AM, Buchanan MJ, Checketts RG (2000) Dall-Miles plating for periprosthetic B1 fractures of the femur. J Arthroplasty 15(1):47–51. [PubMed] 8. Venu KM, Koka R, Garikipati R, Shenava Y, Madhu TS (2001) Dall-Miles cable and plate fixation for the treatment of peri-prosthetic femoral fractures—analysis of results in 13 cases. Injury 32(5):395–400.[PubMed] 9. Schmidt AH, Kyle RF (2002) Periprosthetic fractures of the femur. Orthop Clin North Am 33(1):143–152. [PubMed] 10. Nelson CL (2002) Periprosthetic fractures of the femur following hip arthroplasty. Am J Orthop 31(4):221–223. [PubMed] 11. Springer BD, Berry DJ, Lewallen DG (2003) Treatment of periprosthetic femoral fractures following total hip arthroplasty with femoral component revision. J Bone Joint Surg Am 85-A(11):2156–2162.[PubMed] 12. Ko PS, Lam JJ, Tio MK, Lee OB, Ip FK (2003) Distal fixation with Wagner revision stem in treating Vancouver type B2 periprosthetic femur fractures in geriatric patients. J Arthroplasty 18(4):446–452.[PubMed] 13. Berry DJ (2003) Treatment of Vancouver B3 periprosthetic femur fractures with a fluted tapered stem. Clin Orthop 417:224–231. [PubMed] 14. Berry DJ (2002) Management of periprosthetic fractures: the hip. J Arthroplasty 17(4 Suppl 1):11–13.[PubMed] 15. Clift B (2000) Periprosthetic fracture of the femur. J Bone Joint Surg Am 82(3):446–447. [PubMed] 16. Berry DJ (1999) Epidemiology: hip and knee. Orthop Clin North Am 30(2):183–190. [PubMed] 17. Duncan CP, Masri BA (1995) Fractures of the femur after hip replacement. Instr Course Lect 44:293–304. [PubMed] 18. Brady OH, Garbuz DS, Masri BA, Duncan CP (1999) Classification of the hip. Orthop Clin North Am 30(2):215–220. [PubMed] 19. Engh CA, Massin P, Suthers KE (1990) Roentgenographic assessment of the biologic fixation of porous-surfaced femoral components. Clin Orthop 257:107–128. [PubMed] 20. Harris WH, McCarthy JC, O’Neill DA (1982) Femoral component loosening using contemporary techniques of femoral cement fixation. J Bone Joint Surg Am 64(7):1063–1067. [PubMed] 21. Abendschein W (2003) Periprosthetic femur fractures—a growing epidemic. Am J Orthop 32(9):34–36 (Suppl) [PubMed] 22. Berry DJ (2003) Periprosthetic fractures associated with osteolysis: a problem on the rise. J Arthroplasty 18(3 Suppl 1):107–111. [PubMed] 23. Wang JW, Wang CJ (2000) Periprosthetic fracture of the femur after hip arthroplasty: the clinical outcome using cortical strut allografts. J Orthop Surg (Hong Kong) 8(1):27–31. [PubMed] 24. Cook SD, Barrack RL, Santman M, Patron LP, Salkeld SL, Whitecloud TS 3rd (2000) The Otto Aufranc Award. Strut allograft healing to the femur with recombinant human osteogenic protein-1. Clin Orthop 381:47–57. 25. Porsch M, Galm R, Hovy L, Starker M, Kerschbaumer F (1996) Total femur replacement following multiple periprosthetic fractures between ipsilateral hip and knee replacement in chronic rheumatoid arthritis. Case report of 2 patients. Z Orthop Ihre Grenzgeb 134(1):16–20. [PubMed] 26. Mont MA, Maar DC (1994) Fractures of the ipsilateral femur after hip arthroplasty. A statistical analysis of outcome based on 487 patients. J Arthroplasty 9(5):511–519. [PubMed] Articles from HSS Journal are provided here courtesy of Springer-Verlag                     Document details Title The Parathyriod Glands and Metabolic Bone Disease. Authors ALBRIGHT, F.; REIFENSTEIN, E. C. Book The Parathyriod Glands and Metabolic Bone Disease. 1948 pp. xxvi + 393 pp. Record Number 19512200496 Abstract For more than 20 years, Albright and his colleagues have been studying the biochemical abnormalities of metabolic bone diseases in man, and the clinical phenomena related to them. They have published many papers in that period and now present an outline of their experiences and theories in this well-produced book. The phenomena presented by bone metabolism in health and in disease are discussed and theories related to those phenomena are examined critically according to their usefulness in interpreting the abnormalities of clinical hypo-and hyper-parathyroidism, the osteomalacias, osteoporosis, fibrous dysplasia and Paget's disease. In addition a short chapter is devoted to a consideration of the action of vitamin D and dihydrptachysterpl (A.T. 10). As pointed out in the authors' foreword, the material considered is selected and the book does not constitute a complete textbook. However, it does succeed admirably in presenting and emphasizing general principles and for this reason, in conjunction with the lucid and easy style of writing it should be of interest to all concerned with medical affections of bone. From a veterinary viewpoint the book contains much information of comparative interest and the biochemical data which are presented may afford useful suggestive information in relation to the aetiology of some of the more obscure bone conditions which affect our domestic animals.-J. LOCHIEL McGîRR. جزئیات سند عنوان Parathyriod غدد و بیماری متابولیک استخوان است. نویسنده آلبرایت، F. REIFENSTEIN، E. C. کتاب Parathyriod غدد و بیماری متابولیک استخوان است. 1948 ص XXVI ص 393 شماره ثبت 19512200496 انتزاعی برای بیش از 20 سال، آلبرایت و همکاران او در حال مطالعه اختلالات بیوشیمیایی بیماریهای متابولیک استخوان در انسان و پدیده های بالینی مربوط به آنها است. بسیاری از مقالات آنها در آن دوره منتشر شده و در حال حاضر ارائه یک طرح کلی از تجارب و نظریه های خود را در این کتاب به خوبی تولید شده است. پدیده با متابولیسم استخوان در بهداشت و در بیماری ارائه می شوند مورد بحث و نظریه مربوط به آن دسته از پدیده های در حال انتقادی با توجه به سودمندی آنها در تفسیر اختلالات بالینی هیپو و بیش از حد، parathyroidism، osteomalacias، پوکی استخوان، دیسپلازی فیبری و بیماری پاژه مورد بررسی قرار گرفت. علاوه بر این یک فصل کوتاه به در نظر گرفتن عمل ویتامین D و dihydrptachysterpl (AT 10) اختصاص داده شده است. همانطور که در مقدمه اشاره شده است، مواد مورد نظر انتخاب شده است و این کتاب یک کتاب کامل را تشکیل می دهند. با این حال، موفق تحسین در ارائه و تاکید بر اصول کلی و به همین دلیل، در رابطه با سبک شفاف و آسان از نوشتن آن باید از منافع همه طرفهای درگیر با عواطف پزشکی استخوان می شود. از نظر دامپزشکی کتاب حاوی اطلاعات بسیاری از منافع نسبی و داده های بیوشیمیایی که ارائه شده ممکن است اطلاعات مفیدی مطرح در رابطه با به اتیولوژی از برخی از شرایط مبهم تر استخوان که داخلی ما animals.-J را تحت تاثیر قرار می دهند استطاعت است. LOCHIEL McGîRR.                       )