Quantitative signal intensity ratios to distinguish between subfascial lipoma and atypical lipomatous tumor/well-differentiated liposarcoma using short-tau inversion recovery (STIR) MRI.

PURPOSE: To establish simple quantitative variables at short-tau inversion recovery (STIR) magnetic resonance imaging (MRI) to identify lipomas with high specificity in patients with indeterminate subfascial lipomatous tumors. MATERIALS AND METHODS: The MRI examinations of 26 patients (14 men, 12 women; mean age 63±12.5 [SD] years; range: 40-84years) with histopathologically proven subfascial atypical lipomatous tumors/well-differentiated liposarcomas (ALT/WDLs) and those of 68 patients (32 men, 36 women; mean age, 56±13.5 [SD] years; range: 21-83years) with lipomas were retrospectively reviewed. Ratios derived from region of interest based signal intensity (SI) measurements of tumors and adjacent fat on STIR images were calculated and maximum tumor diameters were noted. Diagnostic parameter capabilities were assessed using ROC curve analysis. Interreader agreement was evaluated by calculation of intraclass correlation coefficients (ICC). RESULTS: Using a cut-off value of 1.18, STIR-SI ratios allowed discriminating between lipoma and ALT/WDL (AUC=0.88; P<0.001) yielding 93% specificity (95% CI: 77-99%) and 74% sensitivity (95% CI: 61-84%) for the diagnosis of lipoma. Interreader agreement was excellent (ICC=0.93). A significant difference in maximum tumor diameter was found between ALT/WDLs (mean: 18.1±6.0 [SD] cm; range: 5.6-33.1cm) and lipomas (mean: 9.7±5.0 [SD] cm; range: 2.9-29.1cm) (P<0.001). Using a cut-off of 11cm, maximum tumor diameter allowed discriminating between lipoma and ALT/WDLs with 92% specificity (95% CI: 75-99%) and 69% sensitivity (95% CI: 57-80%). The combination of a STIR-SI ratio<1.4 and maximum tumor diameter<11cm yielded 100% specificity (95% CI: 87-100%) and 65% sensitivity (95% CI: 54-77%) for the diagnosis of lipoma. CONCLUSION: The combination of STIR-SI ratio and maximum diameter allows discriminating between lipoma and ALT/WDL in initially indeterminate lipomatous tumors.

[Slipped capital femoral epiphysis-etiology and pathogenesis]. / Epiphyseolysis capitis femoris ­ Ätiologie und Pathogenese.

BACKGROUND: Slipped capital femoral epiphysis (SCFE) is the most significant hip disease in adolescence. Because of its typical occurrence at the time of the pubertal growth spurt and some particular clinical symptoms, it has been a topic of special interest in orthopedic research for a long time. A large number of etiological factors have been described, however their meaning in detail is still controversial. OBJECTIVES: After a short summary of the structure and function of the epiphysis, an overview of concepts in the pathogenesis of SCFE is given. MATERIALS AND METHODS: A selective review of literature was performed. RESULTS: Etiology of SCFE includes genetic, endocrinologic, histochemical and biomechanical factors. During puberty, obesity together with reduced femoral antetorsion are the main risk factors for the disease. The rarer atypical SCFE is closely related to metabolic disorders or other chronical diseases. The pathogenesis is characterized by the disproportion between the load-bearing capacity of the epiphysis and the acting forces on the proximal femur. CONCLUSIONS: The concept of the multifactorial etiology of SCFE is convincing. The susceptibility of the femoral epiphysis is explained considering the remarkable biomechanic local forces. The initial damage can be shown on the histological and the histochemical level. Important new aspects refer to the leptin-metabolism. However, in the majority of cases, biomechanical factors seem to be more significant than endocrinological phenomena. A complete understanding has not succeeded to date.

A new technique for correction of leg length discrepancies in combination with complex axis deformities of the lower limb using a lengthening nail and a locking plate.

PURPOSE: Intramedullary lengthening nails are an accepted alternative to external fixators but are limited by anatomical preconditions. Therefore, to date the use of external fixators is sometimes inevitable. We report on a new technique for correction of combined limb length discrepancies and complex axis deformities using solely internal devices - a lengthening nail and a locking plate. METHODS: Between October 2008 and November 2011 five patients (two femora, three tibias) with a mean leg length discrepancy of 36 mm (25 to 50) and a complex angular deformity were treated with a fully implantable motorized lengthening nail (Fitbone) and a locking plate. All patients were evaluated with regards to the pre- and postoperative leg length as well as axis alignment, functional outcome, lengthening indices and complications. RESULTS: A successful leg length equalization was achieved in all cases and physiological joint orientation angles in all but one case. The mean distraction index was 1.2 mm/day, the maturation index 24 days/cm and the consolidation index 35 days/cm. The functional outcome was very encouraging in all cases with bilateral free range of movement. In total, two complications were observed, one nonunion and one loss of leg length after an early locking bolt removal in a peripheral hospital. CONCLUSION: The combination of a fully implantable motorized lengthening nail and a locking plate is a valuable alternative option for treating selected cases with limb length discrepancies in combination with a complex deformity of the lower leg. However, the reported technique puts high demands on the preoperative planning, operative technique as well as surgeon's skills. LEVEL OF EVIDENCE: IV (retrospective series).

[Extracorporeal irradiation : Reimplantation of bone segments in the treatment of malignant bone tumours]. / Die extrakorporale Bestrahlung : Replantation von Knochensegmenten bei malignen Knochentumoren.

BACKGROUND: Malignant bone tumors themselves and the wide resection required because of them may cause huge bone defects in the bone segment involved. Autologous bone grafts are a reliable option to cover these defects in many cases but their availability is limited. Besides common alternative reconstruction methods, including the use of allografts and/or prostheses, especially extracoroporeal irradiation (ECI) and reimplantation of the bone segment involved is attracting increasingly more attention nowadays. DISCUSSION: In the following, we report on indications/contraindications, details of the operative technique, as well as the recommended rehabilitation regime of ECI. Furthermore, we compare our own results with those published in the recent literature. Especially the advantages and disadvantages of this method, the risks and the complications are illustrated and critically discussed. CONCLUSION: Extracorporeal irradiation of a tumor bearing bone segment is a valuable alternative reconstruction technique following tumor resections of the pelvis, femur and tibia, with encouraging results with respect to local control, complication risks and functional outcome.

Treatment of shepherd's crook deformity in patients with polyostotic fibrous dysplasia using a new type of custom made retrograde intramedullary nail: a technical note.

AIMS: The severe form of coxa vara, the 'shepherd's crook deformity', is always a consequence of a locally extensive form of polyostotic fibrous dysplasia (or McCune-Albright syndrome). Treatment of this deformity is a challenge. The soft bone does not tolerate any implant that depends on the stability of the cortical bone (like plates or external fixators). Intramedullary nails are the most appropriate implants for stabilisation, but if they are inserted from the greater trochanter, they cannot correct the varus deformity enough. PATIENTS AND METHODS: We have developed a special intramedullary nail that can be inserted from the osteotomy site and can be driven retrograde into the femoral neck in an appropriate valgus position. We have operated 15 legs in 13 patients. The average age at surgery was 14 years and 5 months (6 to 28.9). In all, 11 femora had been operated before (unsuccessfully) with various implants. RESULTS: The average follow-up was 54.2 months (7 to 132). The average correction of the neck/(distal) shaft angle was 57.5° (10° to 80°) ( = 72.8%). While pre-operatively none of the patients was able to walk without aid, at follow-up only one patient was unable to walk, three used the aid of crutches because of tibial lesions and one patient had an increased external rotation of the leg. At follow-up, most patients were free of pain. One implant broke and had to be replaced. CONCLUSION: This new operative method offers the possibility of efficient correction and stabilisation of this severe and difficult deformation.

Extraskeletal osteosarcoma: A European Musculoskeletal Oncology Society study on 266 patients.

PURPOSE: Prognosis of extraskeletal osteosarcoma (ESOS) is reported to be poorer than that of skeletal osteosarcoma. This multicenter retrospective study aimed to evaluate factors influencing ESOS prognosis. PATIENTS AND METHODS: Members of the European Musculoskeletal Oncology Society (EMSOS) submitted institutional data on patients with ESOS. RESULTS: Data from 274 patients treated from 1981 to 2014 were collected from 16 EMSOS centres; 266 patients were eligible. Fifty (18.7%) had metastases at diagnosis. Of 216 patients with localised disease, 211 (98%) underwent surgery (R0 = 70.6%, R1 = 27%). Five-year overall survival (OS) for all 266 patients was 47% (95% CI 40-54%). Five-year OS for metastatic patients was 27% (95% CI 13-41%). In the analysis restricted to the 211 localised patients who achieved complete remission after surgery 5-year OS was 51.4% (95% CI 44-59%) and 5-year disease-free survival (DFS) was 43% (95% CI 35-51%). One hundred twenty-one patients (57.3%) received adjuvant or neoadjuvant chemotherapy and 80 patients (37.9%) received radiotherapy. A favourable trend was seen for osteosarcoma-type chemotherapy versus soft tissue sarcoma-type (doxorubicin ± ifosfamide) regimens. For the 211 patients in complete remission after surgery, patient age, tumour size, margins and chemotherapy were positive prognostic factors for DFS and OS by univariate analysis. At multivariate analysis, patient age (≤40 years versus >40 years) (P = 0.05), tumour size (P = 0.0001) and receipt of chemotherapy (P = 0.006) were statistically significant prognostic factors for survival. CONCLUSION: Patient age and tumour size are factors influencing ESOS prognosis. Higher survival was observed in patients who received perioperative chemotherapy with a trend in favour of multiagent osteosarcoma-type regimen which included doxorubicin, ifosfamide and cisplatin.

Impact of Single Center Treatment on Ewing Sarcoma 10-Year Long Term Survival Rates.

PURPOSE OF THE STUDY Ewing sarcomas (ES) are the second most common solid malignant bone tumors in both, children and adolescents, and systemic chemotherapy protocols were established during the last 3 decades which proved to be a successful approach in addition to local treatment. The purpose of the present study is (i) to provide survival rates and prognostic factors for patients with ES which received treatment in a single center and (ii) to compare data with results of multicenter studies. MATERIALS AND METHODS Patients (n = 38) were treated by the same surgeon whereas surgery was combined with radiotherapy in 55.3% of the patients (n = 21). Median age at diagnosis was 17.5 years (4.7-60) and the median follow-up time for all patients was 8.2 years (9.8 years for survivors, 3.2 years for non-survivors). RESULTS The survival rate for metastasis free sarcoma decreases from 90.5% to 50% for patients diagnosed with disseminated disease stage. Patients with a good response to chemotherapy survived in 83.3% of the cases. In addition, a higher OS was found for patients younger than 15 years (82.4%) when compared to patients older than 15 years (73.3%). In contrast, multicenter studies reported lower survival rates for metastasis free (~60%) and metastasis stages (< 40%). DISCUSSION The survival rates in the present single center study are higher than the rates reported from multi-center studies although same chemotherapy protocols were used and no substantially difference are apparent for patient population. CONCLUSIONS Based on the present data we re-emphasize that patients with Ewing sarcoma receive appropriate treatment in a large and qualified center particularly considering the survival rates. In addition, our data underline that a close collaboration between the oncological team and the experienced surgeon is crucial for patient's care. Key words: Ewing sarcoma, survival rate, single center, prognostic factors, chemotherapy, surgery, multi center, single center.

Intramedullary lengthening nails: can we also correct deformities?

Unlike external fixators, the use of solid intramedullary lengthening nails is restricted to defined anatomical preconditions, such as an adequate bone length. Furthermore, all deformity corrections except the lengthening procedure have to be implemented intraoperatively and cannot be adjusted postoperatively. Conversely, even complex deformity corrections can be performed using intramedullary devices after a thorough preoperative planning. For preparation of the intramedullary cavity as well as positioning of the lengthening nail according to the preoperative planning, reaming the medullary canal with rigid reamers which don't follow the line of least resistance is inevitable. However, the application of solid lengthening nails might be limited, especially in children with ongoing epiphyseal growth, although a central perforation of the growth plate was shown to have no adverse effects on the growth potential. In cases with complex or multilevel deformities, an additional osteotomy and locking plate fixation could sometimes be a valuable solution in order to avoid external fixation. The low complication rate as well as the reduced compromising of soft tissues and periosteum render intramedullary lengthening nails the state-of-the-art procedure for limb lengthening in combination with deformity correction in patients who meet the anatomical preconditions.

[Acetabuloplasty - The Dega and Pemberton technique]. / Beckenosteotomie nach Dega und Pemberton.

BACKGROUND: Hip dysplasia is the most common congenital deformity requiring surgical correction osteotomy in order to prevent early onset of secondary hip arthrosis. The shape of the acetabulum can be modified by Dega or Pemberton osteotomy and is indicated for hip dysplasia and luxation with irregularities of the socket for children aged between 2 and 12 when the y­physis is still open. METHOD: We will describe indication, contra-indication, preoperative planning as well as details of the Pemberton technique. In addition, we will provide practical advice based on our long-standing experience. RESULTS: We present long-term results from the literature and also from our department. In addition, we will explain and critically discuss our own experiences and the risks and complications of surgical techniques. Good long-term results are reported for acetabuloplasties and Salter osteotomy which are preferred for surgical treatment of hip dysplasia in early life. Advantages and disadvantages of both surgical techniques will be compared in the discussion section. CONCLUSION: Dega and Pemberton acetabuloplasty shows good long-term results regarding prevention of a secondary coxarthrosis. However, correct indication is crucial since this surgical technique is more difficult compared to Salter osteotomy but is also associated with a higher correction potential and a lower complication rate.

Do malignant bone tumors of the foot have a different biological behavior than sarcomas at other skeletal sites?

We analyze the delay in diagnosis and tumor size of malignant bone tumors of the foot in a retrospective study. We compared the oncological and surgical long-term results with identical tumor at other anatomical sites in order to analyze the biological behavior of sarcomas that are found in the foot. Thirty-two patients with a histologically proven malignant bone tumor (fifteen chondrosarcomas, nine osteosarcomas, and eight Ewing sarcomas) between the years 1969 and 2008 were included. The median follow-up was 11.9 years. The overall median time gap between the beginning of symptoms and diagnosis in the study group was 10 months. Ewing sarcoma presented with the longest delay in diagnosis (median of 18 months), followed by osteosarcoma (median of 15 months) and chondrosarcoma (median of 7.5 months). The delay in diagnosis of these tumors was significantly longer than that of equivalent tumors at other skeletal sites, but the 5- and 10-year survival rates and the occurrence of distant metastases were comparable. In contrast, the average size of foot tumors was 5- to 30-fold less than that of tumors analyzed at other skeletal sites. This study indicates that sarcomas of the foot demonstrate a distinct biological behavior compared to the same tumor types at other skeletal sites.

Synovial sarcomas usually metastasize after >5 years: a multicenter retrospective analysis with minimum follow-up of 10 years for survivors.

BACKGROUND: Synovial sarcoma (SS) is a malignant soft tissue sarcoma with a poor prognosis because of late local recurrence and distant metastases. To our knowledge, no studies have minimum follow-up of 10 years that evaluate long-term outcomes for survivors. PATIENTS AND METHODS: Data on 62 patients who had been treated for SS from 1968 to 1999 were studied retrospectively in a multicenter study. Mean follow-up of living patients was 17.2 years and of dead patients 7.7 years. RESULTS: Mean age at diagnosis was 35.4 years (range 6-82 years). Overall survival was 38.7%. The 5-year survival was 74.2%; 10-year survival was 61.2%; and 15-year survival was 46.5%. Fifteen patients (24%) died of disease after 10 years of follow-up. Local recurrence occurred after a mean of 3.6 years (range 0.5-14.9 years) and metastases at a mean of 5.7 years (range 0.5-16.3 years). Only four patients were treated technically correctly with a planned biopsy followed by a wide resection or amputation. Factors associated with significantly worse prognosis included larger tumor size, metastases at the time of diagnosis, high-grade histology, trunk-related disease, and lack of wide resection as primary surgical treatment. CONCLUSIONS: In SS, metastases develop late with high mortality. Patients with SS should be followed for >10 years.

[Intramedullary motorized nail for equalization of posttraumatic leg length discrepancies]. / Ausgleich posttraumatischer Beinverkürzungen mit einem motorisierten intramedullären Nagel.

BACKGROUND: Fractures in childhood may result in a significant leg length discrepancy (LLD). The common correction method of LLD and deformities is callotasis with external fixation. This is often associated with pain, pin site infection, muscle tethering and reduced range of movement (ROM). PATIENTS AND METHODS: Between 2006 and 2008 a total of 11 cases of posttraumatic LLD (range 2.4-4.3 cm) were treated with a fully implanted motorized lengthening device (Fitbone®). Hospitalization time, leg equalization, rehabilitation time and complications compared to external fixation were recorded. RESULTS: Leg lengthening was successfully performed in all cases, in five combined with angular and/or rotatory corrections. The mean distraction index was 1.03 mm/day (range 0.6-1.2 mm/day) and the mean consolidation index was 40 days/cm (range 25.2-50.9 days/cm). The average hospital stay was 9.8 days (range 8-20 days). Bone or soft tissue infections were not observed, nor were the complications commonly associated with external fixation. Functional results were excellent as the preoperative knee ROM was regained in all cases and with improved ROM in three cases. CONCLUSION: The Fitbone® nail is a valuable alternative to conventional methods which reduces complications commonly associated with external fixation.

The outcome of pelvic reconstruction with non-vascularised fibular grafts after resection of bone tumours.

We retrospectively evaluated 18 patients with a mean age of 37.3 years (14 to 72) who had undergone pelvic reconstruction stabilised with a non-vascularised fibular graft after resection of a primary bone tumour. The mean follow-up was 10.14 years (2.4 to 15.7). The mean Musculoskeletal Tumor Society Score was 76.5% (50% to 100%). Primary union was achieved in the majority of reconstructions within a mean of 22.9 weeks (7 to 60.6). The three patients with delayed or nonunion all received additional therapy (chemotherapy/radiation) (p = 0.0162). The complication rate was comparable to that of other techniques described in the literature. Non-vascularised fibular transfer to the pelvis is a simpler, cheaper and quicker procedure than other currently described techniques. It is a biological reconstruction with good results and a relatively low donor site complication rate. However, adjuvant therapy can negatively affect the outcome of such grafts.

Ilizarov hip reconstruction without external fixation: a new technique.

PURPOSE: The Ilizarov hip reconstruction is a well accepted but complication-prone operative salvage procedure in chronically dislocated hips, not least due to the long-term application of external fixation. Although the advantages of fully implantable devices are well known in limb lengthening and are described consistently, until now, external fixation has been used exclusively to perform the Ilizarov hip reconstruction procedure. We present a new technique of Ilizarov hip reconstruction with purely internal implants. METHODS: A 14-year-old girl with a history of spina bifida presented with a 4-cm-short right leg, a Trendelenburg gait and a complex neurological disease expression. Because of refusal of external fixation by the patient and significantly lower complication rates, an Ilizarov hip reconstruction without external fixation was performed. A locking compression plate was applied to fix the proximal femoral valgus-extension osteotomy and a motorised intramedullary distraction nail was used for the distal, lengthening-varisation osteotomy. RESULTS: A healing index of 33 days/cm and full weight bearing after 6 months were noted. At the 1 year follow-up, the patient showed an improvement of the Trendelenburg gait, as well as successful leg equalisation. Satisfaction to a high degree was additionally noted by factors such as reduced pain, the ability to wear workaday clothes and cosmetically appealing scars. No complications were recorded. CONCLUSION: The exclusive use of internal implants for Ilizarov hip reconstruction is a feasible and patient-friendly alternative to traditional methods. Their use, however, may be restricted by geometric preconditions.

Backside volumetric change in the polyethylene of uncemented acetabular components.

Polyethylene wear of acetabular components is a key factor in the development of periprosthetic osteolysis and wear at the articular surface has been well documented and quantified, but fewer data are available about changes which occur at the backside of the liner. At revision surgery for loosening of the femoral component we retrieved 35 conventional modular acetabular liners of the same design. Linear and volumetric articular wear, backside volumetric change and the volume of the screw-head indentations were quantified. These volumes, clinical data and the results from radiological Ein Bild Röntgen Analyse migration analysis were used to identify potential factors influencing the volumetric articular wear and backside volumetric change. The rate of backside volumetric change was found to be 2.8% of the rate of volumetric articular wear and decreased with increasing liner size. Migrated acetabular components showed significantly higher rates of backside volumetric change plus screw-head indentations than those without migration. The backside volumetric change was at least ten times larger than finite-element simulation had suggested. In a stable acetabular component with well-anchored screws, the amount of backside wear should not cause clinical problems. Impingement of the screw-heads could produce more wear particles than those generated at the liner-shell interface. Because the rate of backside volumetric change is only 2.8% of the rate of volumetric articular wear and since creep is likely to contribute a significant portion to this, the debris generated by wear at the backside of the liner may not be sufficient to create a strong osteolytic response.

Extracorporeal irradiation for pelvic reconstruction in Ewing's sarcoma.

We review the treatment of pelvic Ewing's sarcoma by the implantation of extracorporeally-irradiated (ECI) autografts and compare the outcome with that of other reported methods. We treated 13 patients with ECI autografts between 1994 and 2004. There were seven males and six females with a median age of 15.7 years (interquartile range (IQR) 12.2 to 21.7). At a median follow-up of five years (IQR 1.8 to 7.4), the disease-free survival was 69% overall, and 75% if one patient with local recurrence after initial treatment elsewhere was excluded. Four patients died from distant metastases at a mean of 17 months (13 to 23). There were three complications which required operative intervention; one was a deep infection which required removal of the graft. The functional results gave a mean Musculoskeletal Tumor Society score of 85% (60% to 97%), a mean Toronto extremity salvage score of 86% (69% to 100%) and a mean Harris hip score of 92 (67 to 100). We conclude that ECI grafting is a suitable form of treatment for localised and resectable pelvic Ewing's sarcoma.

Intercalary femoral reconstruction with extracorporeal irradiated autogenous bone graft in limb-salvage surgery.

Between 1996 and 2003, 16 patients (nine female, seven male) were treated for a primary bone sarcoma of the femur by wide local excision of the tumour, extracorporeal irradiation and re-implantation. An additional vascularised fibular graft was used in 13 patients (81%). All patients were free from disease when reviewed at a minimum of two years postoperatively (mean 49.7 months (24 to 96). There were no cases of infection. Primary union was achieved after a median of nine months (interquartile range 7 to 11). Five host-donor junctions (16%) united only after a second procedure. Primary union recurred faster at metaphyseal junctions (94% (15) at a median of 7.5 months (interquartile range 4 to 12)) than at diaphyseal junctions (75% (12) at a median of 11.1 months (interquartile range 5 to 18)). Post-operatively, the median Musculoskeletal Tumour Society score was 85% (interquartile range 75 to 96) and the median Toronto Extremity Salvage score 94% (interquartile range 82 to 99). The Mankin score gave a good or excellent result in 14 patients (88%). The range of movement of the knee was significantly worse when the extracorporeally irradiated autografts were fixed by plates rather than by nails (p = 0.035). A total of 16 (62%) of the junctions of the vascularised fibular grafts underwent hypertrophy, indicating union and loading. Extracorporeal irradiation autografting with supplementary vascularised fibular grafting is a promising biological alternative for intercalary reconstruction after wide resection of malignant bone tumours of the femur.

Reconstruction with non-vascularised fibular grafts after resection of bone tumours.

We evaluated 31 patients who were treated with a non-vascularised fibular graft after resection of primary musculoskeletal tumours, with a median follow-up of 5.6 years (3 to 26.7 years). Primary union was achieved in 89% (41 of 46) of the grafts in a median period of 24 weeks. All 25 grafts in 18 patients without additional chemotherapy and/or radiotherapy achieved primary union, compared with 16 of the 21 grafts (76%; 13 patients) with additional therapy (p=0.017). Radiographs showed an increase in diameter in 70% (59) of the grafts. There were seven fatigue fractures in six patients, but only two needed treatment. Non-vascularised fibular transfer is a simpler, less expensive and a shorter procedure than the use of vascularised grafts and allows remodelling of the fibula at the donor site. It is a biological reconstruction with good long-term results, and a relatively low donor site complication rate of 16%.