Inflammatory pseudotumor simulating malignancy: a rare complication after total hip arthroplasty

Purpose: Particulate debris created by accelerated polyethylene wear in totaly replaced hips causes adverse local reactions. We report an extreme form of such a reaction in a patient who developed progressive thigh pain, weakness and numbness after total arthroplasty of his left hip. Methods: An abdominopelvic computed tomogram showed a large intrepelvic cystic mass interpreted as a malignant tumor. Dark greyish-green fluid was aspirated from the cyst and cytopathologic examination showed necrotic debris without malignant cells. Biopsy revealed necrosis and abundant foreign body granulation tissue with polarizable debris. Results: During surgical removal of the cyst a defect of the inner acetabular wall was noted. After successful revision arthroplasty with allograft bone the clinical symptoms improved. Conclusion: A foreign-body reaction to wear debris may produce an intrapelvic mass and corresponding symptoms. Cytologic and histologic examination of the mass or fluid may aid in interpreting the clinical picture and imaging studies.Namen: Tujkov drobir, ki nastaja po vstavitvi popolne kolčne endoproteze, povzroča neželene lokalne odgovore gostitelja. Prispevek povzroča o izraziti obliki takšnega odgovora bolnika, pri katerem je po popolni artroplastiki levega kolka prišlo do naraščajoče stegenske bolečine, izgube mišične moči in odrevenelosti. Metode: Računalniška tomografija spodnjega dela trebuha in medenice bolnika je pokazala veliko cistično tvorbo. Ocenili smo jo kot maligni tumor. Z aspiracijsko biopsijo ciste smo dobili sivo-zeleno tekočino, s citološko preiskavo je bil ugotovljen nekrotični drobir brez malignih celic. Z biopsijo smo potrdili nekroze in obilno granulacijsko tkivo tujkovega tipa z drobirjem, ki je pod polarizacijskim mikroskopom značilno lomil svetlobo. Rezultati: Med kirurško odstranitvijo cistične tvorbe smo opazili defekt kostnine notranje stene kolčnice. Po uspešni revizijski artroplastiki in uporabi homolognih kostnih presadkov so bolnikove težave izzvenele. Zaključki: Vnetna reakcija tujkovega tipa na obrabne delce endoproteze lahko povzroči rast medeničnega tumorja in posledične simptome. Citološka in histološka preiskava tumorja ali njegove tekoče vsebine lahko pomaga razložiti klinično sliko in izvide slikovnih diagnostičnih preiskav

Kirurško zdravljenje akutnega izpaha pogačice s kostnim odlomkom pri otrocih

Purpose: The management of acute patellar dislocation in children and adolescents is controversial. Traditionally,most first time traumatic patellar dislocations have been treated nonoperatively. However, due to new knowledge about medial patellar stabilizers some authors have advocated for surgical repair. The present report describes the midterm subjective and functional results of operative treatment of acute patellar dislocation in children less than eighteen years of age with concomitant osteochondral fracture. Methods: Data on a cohort of sixteen patients (eight girls and eight boys) aged 14.9 years (mean, range12-17 years) with acute patellar dislocation were retrospectively collected. Intraarticular fragments were detected in all patients in conventional radiographs. Operative treatment consisted of arthroscopic removal (12cases) or refixation (4 cases) of the osteochondral fragments and direct repair of the damaged medial patellofemoral ligament (MPFL) if that was still feasible (13 cases). All patients were seen at six months, and a telephone interview with twelve patients (75%) was conductedat four years (mean, range 27 years). Results: Of the sixteen patients, two (12.5%) had a recurrent patellar luxation. The subjective IKDC score at the time of the most recent follow up was 86 (mean, range 63-100), and the Marx Activity Rating Scale score was 9.2 (mean, range 216).Conclusions: Direct surgical repair of the injured MPFLmay be considered an option to prevent subsequent dislocation and subluxation in first time traumatic dislocation of the patella in children and adolescents with osteochondral fractures and substantial disruption of medial patellar stabilizers.Namen: O zdravljenju akutnega izpaha pogačice pri otrocih in mladostnikih še ni jasnega konsenza. Tradicionalno zdravljenje prvega poškodbenega izpaha pogačice je bilo konzervativno, zaradi novih spoznanj o medialnih stabilizatorjih pogačice pa nekateri avtorji v zadnjem času priporočajo operacijsko zdravljenje. Pričujoča raziskava opisuje srednjeročne subjektivne in funkcionalne rezultate operacijskega zdravljenja akutnega izpaha pogačice s pridruženim osteohondralnim odlomkom pri otrocih in mladostnikih, mlajših od osemnajst let. Metode: Retrospektivno smo zbrali podatke 16 bolnikov (osmih deklic in osmih dečkov), povprečno starih 14,9 (12-17) let z akutnim izpahom pogačice. Pri vseh bolnikih smo na rentgenskih posnetkih ugotovili prisotnost znotrajsklepnih odlomkov. Bolnike smo operacijsko zdravili z artroskopsko odstranitvijo (12 primerov) ali refiksacijo (4 primeri) osteohondralnih odlomkov in neposrednim popravilom medialne patelofemoralne vezi, kjer je bilo to še mogoče (13 primerov). Bolnike smo pregledali po šestih mesecih in z dvanajstimi (75 %) opravili telefonski pogovor po povprečno štirih (2-7) letih. Rezultati: Dva izmed 16 bolnikov (12,5 %) sta imela ponovni izpah pogačice. Povprečno doseženo število točk po subjektivnem IKDC točkovniku ob zadnjem sledenju je bilo 86 (63-100), po Marx Activity Rating Scale pa 9,2 (216). Zaključki: Neposredna kirurška rekonstrukcija medialne patelofemoralne vezi predstavlja možnost preprečitve ponovne dislokacije in subluksacije pogačice. Posebej primerna je lahko ob prvem travmatskem izpahu pogačice pri otrocih in mladostnikih z osteohondralnimi zlomi in obsežnejšo okvaro medialnih stabilizatorjev pogačice

Total Knee Replacement with an Uncemented Porous Tantalum Tibia Component: A Failure Analysis

Porous tantalum has been extensively used in orthopaedic surgery, including uncemented total knee arthroplasty (TKA). Favourable results were reported with earlier monobloc tibial components and the design evolved to modular implants. We aimed to analyse possible causes for extensive medial tibia bone loss, resulting in modular porous tantalum tibia baseplate fracture after primary TKA. Retrieved tissue samples were scanned with 3 MeV focused proton beam for Proton-Induced X-ray Emission (micro-PIXE) elemental analysis. Fractographic and microstructural analysis were performed by stereomicroscopy. A full 3D finite-element model was made for numerical analysis of stress–strain conditions of the tibial baseplate. Histological examination of tissue underneath the broken part of the tibial baseplate revealed dark-stained metal debris, which was confirmed by micro-PIXE to consist of tantalum and titanium. Fractographic analysis and tensile testing showed that the failure of the tibial baseplate fulfilled the criteria of a typical fatigue fracture. Microstructural analysis of the contact surface revealed signs of bone ingrowth in 22.5% of the surface only and was even less pronounced in the medial half of the tibial baseplate. Further studies are needed to confirm the responsibility of metal debris for an increased bone absorption leading to catastrophic tibial tray failure