Контроль после эндопротезирования коленного сустава.

Да, v1tal прав, это старая методика, у нас уже лет 8-9 как делают (1-2 в неделю). Я как раз и предлагаю поговорит о описании таких снимков, поначалу врачи не всегда знают что и как описывать.

The initial films serve as a baseline study and are used as reference films for comparison with all future studies, since sequential radiography is the most valuable method for detecting complications.
The initial postoperative films are obtained to look for possible dislocation or fracture and to see if the prosthesis is good positioned.

После установки эндопротеза; сразу после операции или на следующий день; выполняются снимки в стандартных проекциях. Эти снимки необходимы не только как контроль стояния частей протеза или на предмет конгруэнтности суставных поверхностей; в принципе все эти критерии должны быть оценены во время операции (под контролем C-arm); но как "эталонный" снимок, с которым потом будут сравниваться последующие контрольные исследование, если что-то пойдёт не так (в случае осложнений). На первичном контрольном снимке мы оцениваем стояние протеза, конгруэнтность, подтверждаем отсутствие (или наличие) надломов, переломов или вывихов. Ниже привожу фрагмент статьи из Imaging по данной тематике:

Imaging 15:270-285 (2003)
© 2003 The British Institute of Radiology

Imaging of prosthetic joints

S Ostlere, FRCR and S Soin, MB BChir

Nuffield Orthopaedic Centre and Oxford Radcliffe Hospital, Oxford, UK

• Plain films are usually sufficient to assess the state of a prosthesis.
• Criteria for loosening depends on site and make of prosthesis.
• The wider and more extensive the periprosthetic lucency is, the higher the chance of loosening. Progressive changes are more significant.
• Scintigraphy is a sensitive but non specific technique for diagnosing loosening.
• Ultrasound and MRI are useful for assessing soft tissue collections.
• Diagnosing infection may require aspiration, biopsy or capsular frozen section.

The changing demographics of our society and improvements in surgical techniques have meant that an increasing percentage of the population has one or more prosthetic joint. Imaging is required for the initial assessment, routine follow up and in patients with suspected complications. The radiologist should have sufficient background knowledge regarding the operative techniques employed in joint replacement surgery to be able to make an accurate assessment of radiographs of prosthetic joints. The radiologist should also be aware of the strengths and limitations of the various techniques available to investigate complications. As joint replacement has become more prevalent, a myriad of prostheses have become available. The radiological criteria for diagnosing failure of a prosthesis may depend on the type of prosthesis and technique used. Plain films are the mainstay for assessing joint replacements, and most management decisions can be made without resort to more complex imaging. Ultrasound, MRI scintigraphy, arthrography, aspirations and biopsies all have a part to play in the investigation of complications.

	The knee

Top Summary The hip The knee The shoulder Elbow The ankle Conclusions References

 
It is estimated that more than 35 000 knee replacements were performed in the UK in the year 2000. Imaging follows similar principles to that of the hip, with one or two additional features relating to the design of the prosthesis. Most prosthetic knees consist of metallic femoral and metal backed polyethylene tibial components (which may be cemented or non-cemented). A patella button may be used where necessary. As with the hip, aseptic loosening and infection are the most common complications. Ongoing pain in the knee without features of loosening is also recognised.

Although the radiological criteria for loosening are not as well established as that for the hip, a scoring system for monitoring progression has been developed by the Knee Society. The score for a component is the sum of the maximum width of lucency for a given specified zone (Figure 22). For the commonly affected 7-zone tibial component a score of greater than 10 implies impending failure whereas a score of less than 4 without progression can be regarded as not significant [21] (Figure 23). Areas of ill defined bony resorption suggest infection (Figure 24). As with all prostheses, migration or marked osteolysis also indicates impending prosthetic failure.

View larger version (121K): [in this window] [in a new window]   Figure 22. The seven zone of the tibial component used by the Knee Society scoring system.

View larger version (89K): [in this window] [in a new window]   Figure 23. Aseptic loosening of a total knee replacement. (a) Normal immediate post-operative film. (b) 3 years following surgery there is a wide radiolucency under the tibial plate and around the stem at the bone/cement and prosthesis/cement interfaces (arrows).

View larger version (129K): [in this window] [in a new window]   Figure 24. Infected total knee replacement. There is extensive bony destruction around the tibial component (arrows).

 
Unicompartmental replacements are used predominately for medial osteoarthritis when lateral joint space is preserved as determined by pre-operative valgus stress view or MRI. The signs of loosening and infection are similar to those seen in total knee replacements except that lucency around the tibial component of the commonly used Oxford prosthesis is a normal finding (Figures 25 and 26).

View larger version (102K): [in this window] [in a new window]   Figure 25. Unicompartmental knee replacement. There is lucency at the bone/cement interface of the tibial component which is within normal limits for this particular design.

View larger version (90K): [in this window] [in a new window]   Figure 26. Infected unicompartmental knee replacement. (a) The immediate post-operative pictures show normal replacement. (b) 1 month later there is bone destruction under the tibial plate (arrows) and (c) loss of lateral joint space.

 
The imaging of complications of prostheses may be challenging. Fractures, dislocations and most cases of aseptic loosening can be diagnosed with a combination of clinical and plain radiographic features. Differentiating aseptic loosening from infection may be impossible on clinical or imaging criteria and biopsy of the periarticular tissue either prior to or at the time of surgery may be necessary.

Пустоту Вы подметили правильно; но у нас в последнее время всё реже используют классический костный цемент при эндопротезировании, вместо него заливают специальный медицинский клей; он рентгено-прозрачен.