Severe metallosis-related osteolysis as a cause of failure after total knee replacement.

BACKGROUND: Metallosis is a syndrome of metal-induced synovitis caused by friction between two metal surfaces. In contrast to the hip joint after resurfacing arthroplasty or metal-on-metal (MoM) total hip replacement, metallosis of the knee is extremely rare. MATERIALS: We describe 4 patients who underwent revision total knee replacement because of disabling pain and implant loosening after a mean time of 21 (range: 13-30) years of knee replacement surgery. They were all females with a mean age of 79 (range: 75-82) years. Septic loosening was excluded through microbiological examination and synovial fluid analysis. RESULTS: Direct metal-on-metal contact at the tibiofemoral interface was confirmed intraoperatively in all cases. All knees showed severe metallosis with advanced osteolysis and pseudotumor formation. In one knee there was a complete fracture of the tibial tray. All patients had a one-stage revision surgery with implant removal, profound synovectomy and implantation of a constrained modular revision knee system. Long modular stems with offset adapters, wedges and/or blocks were used in all cases. CONCLUSION: Metallosis-associated osteolysis should be suspected in cases with radiologically evident polyethylene wear after knee replacement. Recognizing that revision arthroplasty is very technically demanding in such cases, surgeons should have a back-up with modular revision components and a ready access to reconstructive options at this revision setting.

Osteosarcoma of the pelvis: experience of the Cooperative Osteosarcoma Study Group.

PURPOSE: To define patients and tumor characteristics as well as therapy results, patients with pelvic osteosarcoma who were registered in the Cooperative Osteosarcoma Study Group (COSS) were analyzed. PATIENTS AND METHODS: Sixty-seven patients with a high-grade pelvic osteosarcoma were eligible for this analysis. Fifteen patients had primary metastases. All patients received chemotherapy according to COSS protocols. Thirty-eight patients underwent limb-sparing surgery, 12 patients underwent hemipelvectomy, and 17 patients did not undergo definitive surgery. Eleven patients received irradiation to the primary tumor site: four postoperatively and seven as the only form of local therapy. RESULTS: Local failure occurred in 47 of all 67 patients (70%) and in 31 of 50 patients (62%) who underwent definitive surgery. Five-year overall survival (OS) and progression-free survival rates were 27% and 19%, respectively. Large tumor size (P =.0137), primary metastases (P =.0001), and no or intralesional surgery (P <.0001) were poor prognostic factors. In 30 patients with no or intralesional surgery, 11 patients with radiotherapy had better OS than 19 patients without radiotherapy (P =.0033). Among the variables, primary metastasis, large tumor, no or intralesional surgery, no radiotherapy, existence of primary metastasis (relative risk [RR] = 3.456; P =.0009), surgical margin (intralesional or no surgical excision; RR = 5.619; P <.0001), and no radiotherapy (RR = 4.196; P =.0059) were independent poor prognostic factors. CONCLUSION: An operative approach with wide or marginal margins improves local control and OS. If the surgical margin is intralesional or excision is impossible, additional radiotherapy has a positive influence on prognosis.

Study of osteointegration of a titanium prosthesis to the stapes: observations on an accidentally extracted stapes.

BACKGROUND: Titanium is a well-established implant material, and its use in ossicular chain reconstruction during middle ear surgery is increasing. HYPOTHESIS: Bony fixation of titanium prostheses has to be considered using this material. Contact with bony structures of the middle ear may result in immobilization. In revision procedures, there is a potential risk of damaging or extracting adherent structures such as the stapes. METHODS: This is a case report of an accidentally extracted stapes resulting from bony fixation of a titanium prosthesis in revision tympanoplasty. The surgical specimen was examined by microscopy, histology, and scanning electron microscopy. Energy dispersive x-ray analysis was used to confirm the elemental composition of the extracted stapes and the titanium prosthesis. RESULTS: The prosthesis showed good biocompatibility at the implantation site, with signs of bone resorption of the stapes suprastructure. However, bony fixation of the undersurface of the prosthesis foot to the stapes footplate was confirmed by ultrastructural analysis. CONCLUSION: In revision tympanoplasty, bony fixation of the titanium prosthesis should be considered.

Chromosomal alterations in osteosarcoma cell lines revealed by comparative genomic hybridization and multicolor karyotyping.

We characterized the chromosomal alterations in eight osteosarcoma cell lines (OST, HOS, U-2 OS, ZK-58, MG-63, SJSA-1, Saos-2, and MNNG) by comparative genomic hybridization (CGH); gains and losses of DNA sequences were defined as chromosomal regions with a fluorescence ratio, wherein all of the 95% confidence interval was above 1.25 and below 0.75, respectively. In four of 8 cell lines, multicolor karyotyping (MK) was added. CGH revealed the average number of aberrations per cell line was 20.8 (range: 10-31); the average numbers of gains and losses were 11.1 and 9.6, respectively. The frequent gains were identified on 1p21 approximately q24, 1q25-q31, 7p21, 7q31, 8q23 approximately q24, and 14q21; frequent losses were at 18q21 approximately q22, 18q12, 19p, and 3p12 approximately p14. High-level gains were observed on 8q23 approximately q24, 5p, and 1p21 approximately p22. MK revealed the most common translocations in the four cell lines were t(8;9), t(1;3), t(3;5), t(1;13), t(2;6), t(3; 17), t(1;15), t(10;20), and t(6;20). Chromosomes 1, 3, 8, 9, and 20 were most frequently involved in translocation events. The concordance rate of aberrations in CGH and translocations in MK was 76%. MK was useful to identify the chromosomal alterations and as a supplement to the CGH results in three of four chromosomes.

Comparative genomic hybridization in cartilaginous tumors.

Genetic aberrations in cartilaginous tumors have not yet been well characterized. We analyzed the molecular-chromosomal aberrations in 10 chondrosarcomas (four Grade-3 tumors, four Grade-2 tumors and two Grade-1 tumors) and in three benign cartilaginous tumors (two enchondromas and one chondromyxoid fibroma). Genomic imbalances were detected in 9 out of 10 cases of chondrosarcomas. The median number of changes was 7.0 per tumor (range 0-23) and the gain-to-loss ratio was 1:1.4. The most frequent gains involved 7q, 5p, or 21q and the most frequent losses were 17p, 13q, 16p, or 22q. The three benign cartilaginous tumors each had two (0 gains and two losses), six (one gain and five losses) and eight (one gain and seven losses) chromosomal aberrations. Both of the gains occurred on 13q21 and losses were frequently observed on chromosomes 19 and 22q in all three cases. Loss of chromosomes 16p, 17p, 22q, or 19 loss were common in both chondrosarcomas and benign cartilaginous tumors. However, aberrations from chromosomes 2 to 11, 14, 15, 18, or 21 were detected only in chondrosarcomas. Therefore, although the number of aberrations between benign and malignant cartilaginous tumors appears to be similar, these two entities may be differentiated by determining which chromosomes are affected.

Incidence and mechanisms of infiltration of sarcomas in the shoulder.

The intraarticular infiltration of sarcomas around the shoulder was analyzed. Of 58 sarcomas located around the shoulder, which were treated between 1993 and 1998, 15 osteosarcomas, 12 chondrosarcomas, and one Ewing's sarcoma that abutted the shoulder were selected. Radiologic images of 28 tumors were analyzed and compared with pathologic examinations. In 17 of 28 sarcomas (15 in the proximal humerus and two in the scapula), joint infiltration was suspected radiologically because of the existence of a tumor mass probably inside the joint or disruption of the joint surface and protrusion of the tumor. Seven of 17 tumors with radiologically positive and zero of 11 tumors with radiologically negative findings showed histologically positive findings for tumor inside the joint. Four of 11 osteosarcomas and three of four chondrosarcomas of the proximal humerus showed histologic findings of joint infiltration. Pericapsular extension was seen in two patients, direct articular spread with a pathologic fracture was seen in two patients, direct articular spread was seen in one patient, direct articular spread with pericapsular extension was seen in one patient, and pericapsular extension with a pathologic fracture was seen in one patient. The current study showed that pericapsular or direct articular infiltration into the glenohumeral joint is a phenomenon in sarcoma around the shoulder. Exact assessment of tumor existence inside the joint can be difficult in osteosarcoma and chondrosarcoma, so abnormal radiologic findings should be regarded as proof of existence of tumor, and extraarticular wide resection should be planned.

Rotationplasty--quality of life after 10 years in 22 patients.

We assessed the long-term results in 22 patients with rotationplasty after resection of high-grade malignant bone tumors. We used established methods (QLQ-C 30; FLZ) to evaluate the quality of life, diplomas, life-contentment, occupational situation and marriage status. After 10-year follow-up, we found no reduction in psychosocial adaptation, and life contentment was about the same as in healthy persons. We therefore recommend rotationplasty instead of amputation whenever conventional limb salvage is impossible.

Sacral infiltration in pelvic sarcomas: joint infiltration analysis II.

The incidence and characteristics of sacral infiltration in pelvic sarcomas were analyzed. Fifty-one patients with a pelvic sarcoma (chondrosarcoma, 15 patients; Ewing's sarcoma, 23 patients; and osteosarcoma, 13 patients) abutting the sacroiliac joint had surgical treatment. Tumor infiltration into the sacrum was suspected based on preoperative images in 18 patients; 15 of 18 patients had histologic tumor invasion. There was a significant difference of median volume of sarcomas with and without infiltration. One of 23 Ewing's sarcomas, seven of 15 chondrosarcomas, and seven of 13 osteosarcomas penetrated the sacroiliac joint into the sacrum. Logistic regression test showed that diagnosis was the most important factor influencing sacral infiltration. Twelve tumors infiltrated through the posterior part of the joint, two tumors infiltrated through the anterior part, and one large tumor infiltrated through an unknown route. To obtain wide surgical margins, patients at risk (elderly, large tumor, or diagnosis of osteosarcoma or chondrosarcoma) for sacral involvement may require extended internal hemipelvectomy with the medial margin extending into the sacrum. High quality imaging studies should be used to assess the need for transarticular resection.

Implantation of hemipelvic prosthesis after resection of sarcoma.

Twelve adult patients with pelvic sarcoma had implantation of a hemipelvic prosthesis. Eight patients had hemipelvic resection, and four patients had acetabulopubic resection. The implanted prosthesis was a special Vitallium prosthesis, which was specially designed for each patient with the aid of a computer. At a median followup of 57 months, eight patients were free of disease. In four patients with local relapse, two had additional resection, one had hindquarter amputation, and one was observed. In three patients with deep infection, the prosthesis was removed; however, one patient had hindquarter amputation. One patient had dislocation of the hip and prosthesis loosening. Overall survival of patients was 70%, and the survival of prostheses was 42%. In eight patients, the functional evaluation showed that the average functional score with the prosthesis was 11.6 (39%) and without the prosthesis the functional score was 7.0 (23%). Implantation of a megaprosthesis seems to indicate a high complication rate and a poor functional result after hemipelvic resection.

Infiltration of sarcomas into the hip joint: comparison of CT, MRI and histologic findings in 67 cases.

We analyzed the incidence, route, and characteristics of hip joint infiltration in pelvic or proximal femoral sarcomas. 67 patients with a sarcoma that originated around the hip joint (50 pelvic and 17 femoral) were included in this study. Preoperative CT and MRI were matched with the histological findings in tumor specimens. Tumor infiltration into the hip joint was suspected on the basis of preoperative imaging in 29 patients due to articular cartilage disruption, diffuse signal changes in the acetabulum or femoral neck, signs of a tumor in the joint, or markedjoint effusion. Of these 29 patients, 15 showed tumor invasion on histological examination. 12 of 31 chondrosarcomas, none of 12 Ewing's sarcomas, and 3 of 24 osteosarcomas infiltrated into the hip joint (p = 0.008). 10 of 26 low-grade sarcomas and 5 of 41 high-grade sarcomas infiltrated into the hip joint (p = 0.02). The joint infiltration rate of the chondrosarcomas was related to their size. Of 10 tumors originating in the acetabulum, 9 penetrated through or around the osseous-ligamentous junction and one through the acetabular cartilage. In 5 proximal femur lesions, all infiltrated the joint through the femoral neck, 3 of them also through the ligamentum teres.

Correction of leg-length discrepancy after hip transposition.

Four patients were treated with limb lengthening to correct a leg-length discrepancy that developed after a hip transposition after pelvic resection for sacroma of the pelvis. Three patients had Ewing's sacroma and one patient had osteosarcoma. All patients received chemotherapy; radiotherapy also was administered to the three patients with Ewing's sacroma. Femur lengthening was started at an average of 5.7 years (range, 4.4-6.8 years) after tumor surgery. At the start of elongation, the average age of the patients was 17.3 years (range, 10.3-20.8 years). The average leg-length discrepancy was 10.3 cm (range, 6-12 cm). The average of achieved lengthening was 6.4 cm (range 6-7.5 cm). The average healing index was 32 days (range, 27-40 days) per 1-cm elongation. According to the classification of Paley, two problems and two minor complications were treated by additional interventions. At the final followup, the average functional score was 22 (73%) according to the system of the Musculoskeletal Tumor Society. Leg-length discrepancy after hip transposition can be corrected with distraction osteogenesis. All patients who wore a stiff ankle-foot orthosis before lengthening wore an ordinary shoe lift after lengthening. The problems of the lengthening procedure are similar to the general complication rate of bone lengthening. Because the 5-year survival after resection of a pelvic sarcoma is only 20% to 30%, leg lengthening after hip transposition should be offered only to long-term survivors with at least 5 years event-free survival.

Osteoid osteoma and osteoblastoma of the spine: experiences with 22 patients.

Osteoblastomas and osteoid osteomas of the spine are relatively rare bone-forming tumors. Between 1980 and 1999, nine patients with osteoid osteoma and 13 patients with osteoblastoma had surgery for their tumors. Four tumors were in the cervical spine, six tumors were in thoracic spine, 10 tumors were in the lumbar spine, and two tumors were in the sacrum. The average duration between onset of pain and surgery was 16.6 months in 12 patients treated in the 1980s and 8.6 months in 10 patients treated in the 1990s. Seventeen patients had scoliosis. In nine of 10 patients with magnetic resonance imaging scans, high signal intensity areas in the muscles and bone around the lesion were seen. Two of nine patients with osteoid osteoma and nine of 13 patients with osteoblastoma had neurologic disorders before treatment. All patients had open resection of the lesions. Two patients with osteoid osteoma had relapse because of incomplete resection, necessitating a second excision. In 16 of 17 patients with preoperative spinal deformity, the deformity improved during followup. With development of modern imaging techniques, exact surgical planning may become possible; however, in some cases, intraoperative complete resection of the lesion still is difficult.

Genetic imbalances revealed by comparative genomic hybridization in osteosarcomas.

Osteosarcomas are the most frequent bone sarcomas. The molecular chromosomal aberrations in osteosarcomas were analyzed by comparative genomic hybridization (CGH). We studied 47 frozen tumors (41 primary samples, 6 relapses) in osteosarcoma patients registered in the Cooperative Osteosarcoma Study (COSS) protocol. Genomic imbalances were detected in 40 of 41 primary tumors and 6 of 6 relapsed tumors. Gains were more frequent than losses (ratio of 1.3:1). The median number of changes was 16 and 12 in primary and relapsed osteosarcomas, respectively. The median number of aberrations in primary high-grade osteosarcomas (17.0) was significantly higher than in low- or intermediate-grade osteosarcoma subtypes (3.0) (p = 0.038). The most frequent gains included 8q, 1p21-p31 and 1q21-q24, and the most frequent losses were 10q, 5q and 13q. High-level gains were observed on 8q23-q24, 17p13 and 1q21-q24. A gain of 19p (p < 0.001) or loss of 9p (p = 0.027) was more frequent in poor responders than in good responders. Univariate analysis revealed that patients with primary metastases (p = 0.002), poor histologic responses (p = 0.005), high-level gains of 19p (p = 0.012) or losses of 13q14 (p = 0.042) had significantly lower event-free survival (EFS), whereas patients with a loss of 5q (p = 0.007) or a loss of 10q21-22 (p = 0.017) had significantly higher EFS than patients without these aberrations. Multivariate analysis demonstrated that primary metastasis, loss of 13q14 and loss of 5q were independent prognostic factors. The findings of our study seem to be useful for evaluating the prognosis of patients and may finally lead to treatment strategies based on genetic background of osteosarcoma.