Tumor Endoprostheses Research Articles

Custom-made hinged spacers in revision knee surgery for patients with infection, bone loss and instability

Polymethyl methacrylate spacers are commonly used during staged revision knee arthroplasty for infection. In cases with extensive bone loss and ligament instability, such spacers may not preserve limb length, joint stability and motion. We report a retrospective case series of 19 consecutive patients using a custom-made cobalt chrome hinged spacer with antibiotic-loaded cement. The “SMILES spacer” was used at first-stage revision knee arthroplasty for chronic infection associated with a significant bone loss due to failed revision total knee replacement in 11 patients (58%), tumour endoprosthesis in four patients (21%), primary knee replacement in two patients (11%) and infected metalwork following fracture or osteotomy in a further two patients (11%). Mean follow-up was 38 months (range 24–70). In 12 (63%) patients, infection was eradicated, three patients (16%) had persistent infection and four (21%) developed further infection after initially successful second-stage surgery. Above knee amputation for persistent infection was performed in two patients. In this particularly difficult to treat population, the SMILES spacer two-stage technique has demonstrated encouraging results and presents an attractive alternative to arthrodesis or amputation.

Mega Prosthetic Knee Replacement For Treatment of Resistant Distal Femoral Non Union

The incidence of non-union in distal femoral fractures has been reported from 0 to 13%. Treatment of these fractures has always been challenging and there is still no established consensus on ideal treatment of nonunion of such fractures. Preservation of knee function and early weight bearing should be the objectives of management to have best clinical outcome. We report treatment of three cases of distal femoral fractures which had failed to unite despite prior internal fixation with a distal femoral tumor endoprosthesis (megaprosthesis) originally developed for use in musculoskeletal tumor surgery as a treatment option as an alternative to internal fixation. The Knee Society Score increased form 35 to 78 & Knee Society Function Score increased form 5 to 80 in these patients. Our patients had good range of motion (70-90 degree flexion) at 8 months of follow up and were walking pain free without the need of any ambulatory support. We thus conclude that cemented Megaprosthesis appears to be a viable one time treatment solution for failed internal fixation of distal femoral fractures, associated with distal femoral bone loss and secondary knee arthritis with or without ligamentous instability in elderly patients.

Histologic Examination of Leeds-Keio Artificial Ligament Implanted on the Surface of a Tumor Endoprosthesis

The Leeds-Keio (L-K) artificial ligament is made of polyester fibers with an open-weave mesh structure. It has been used clinically for knee ligament reconstruction as a scaffold, allowing tissue ingrowth and new ligament formation. We have used the L-K ligament in bone tumor surgery for reattaching remaining muscles to the target zone of a tumor endoprosthesis. We histologically examined the L-K ligament obtained from 2 patients during revision surgery 39 months after the primary surgery. There were dense fibrous tissues between muscles and the L-K ligament. Collagen fibers proliferated in the space between the polyester fibers, and a slight inflammatory reaction was apparent. We concluded that the L-K ligament had a high potential for inducing biological tissue regeneration even on the metal surface.

Muscle function of the thigh 10 years following a malignant bone tumor and implantation of a tumor prosthesis in the knee

To objectify the muscle function of 5 patients ten years after implantation of a tumor endoprosthesis of the knee simultaneous muscle force and IEMG was recorded. The muscular activity in the operated leg was found to be reduced for the extension muscles (8-20%) and for the flexion muscles (28-52%) when comparing to the normal leg. Knee extension of the operated leg resulted from the function of the rectus femoris muscle. During normal exercise in daily life all patients were not handicapped und some of them did sport.

Two-Stage Revision of Infected Uncemented Lower Extremity Tumor Endoprostheses

We reviewed our experience with 2-stage revision of uncemented Kotz Modular Femoral and Tibial Replacement System prostheses from 1989 to 2004. A total of 180 lower extremity tumor prostheses were inserted, 15 of which underwent removal of the prosthesis for infection. Eleven patients underwent subsequent second-stage revision, and 4 underwent amputation. Of the 11 patients who underwent revision, 8 continue to be free of infection an average of 33 months postoperatively. Of these 8 patients, 6 were revised without removal of the diaphyseal anchorage piece, which were all well ingrown. Most successful revisions were in the group that developed infection within 6 months of their original procedure. Two-stage revision of uncemented tumor endoprostheses with retention of a well-ingrown stem can be associated with successful eradication of infection.

Effect of Chemotherapy on Initial Compressive Osseointegration of Tumor Endoprostheses

Chemotherapy has long been suspected of having an adverse effect on bone healing. Massive tumor endoprostheses which achieve osseointegration via compressive force provide a unique model to study the effects of chemotherapy on bone healing. We compared distal femoral bone hypertrophy in patients who received chemotherapy with those who did not. Fifty four patients underwent distal femoral reconstruction with a compression implant. Thirty patients received chemotherapy (Group 1), and 24 did not (Group 2). The group of patients receiving chemotherapy was younger, had lower body mass indices, and had different diagnoses compared to the group of patients not receiving chemotherapy. We used a standardized technique to measure bone growth at the bone-prosthetic interface. The rate of cortical width increase at the bone-prosthetic junction was faster in Group 2 compared to Group 1. Similarly, the increase in cortical width from immediate postop to 3 months and 6 months postop was greater in Group 2 when compared to Group 1. The data suggest chemotherapy administration for musculoskeletal malignancy has a substantial initial adverse effect on bone hypertrophy and a trend towards reduced prosthetic survival. These findings have important implications for the patients with musculoskeletal tumors.

Functional results and quality of life after shoulder girdle resections in musculoskeletal tumors

From 1981 to 2001, 91 shoulder resections were performed to treat shoulder girdle tumors (64 primary and 27 metastatic) in 90 patients (53 male and 37 female patients). The mean age was 34 years in patients with a primary tumor and 61 years in those with metastases. There were 7 partial scapulectomies, 13 total scapulectomies, 56 proximal humeral resections, 5 diaphyseal resections, 5 total shoulder girdle resections (Tikhoff-Linberg procedure), and 5 other procedures performed. Prosthesis implantation was carried out in 41 cases, autologous fibular transposition was done in 19, and massive homologous bone grafting was done in 4. Of the patients, 37 were clinically reviewed with a mean follow-up of 4.7 years (range, 1-20 years) by use of the recommendations of the Musculoskeletal Tumor Society for pain, function, position of hand, lifting ability, manual dexterity, and satisfaction. Nine patients were reviewed via a questionnaire and telephone interview. Twenty-six had died, and eighteen were lost to follow-up. The best results were achieved after partial scapulectomy and after humeral resection reconstructed with fibular transposition, when the function of the rotator cuff was preserved. After total scapulectomy and after humeral resection with the implantation of a tumor endoprosthesis, the function of the shoulder remained moderate because the rotator cuff was damaged. The overall satisfaction was generally good after all types of shoulder resections as a result of pain relief, preserved hand function, and improvement of psychological status. Patients can compensate extremely well by using the preserved joints and the contralateral upper limb; therefore, patient satisfaction does not rely on shoulder function alone.

The Influence of Elementary Silver Versus Titanium on Osteoblasts Behaviour In Vitro Using Human Osteosarcoma Cell Lines

Purpose. The antimicrobial effect of a silver-coated tumor endoprosthesis has been proven in clinical and experimental trials. However, in the literature there are no reports concerning the effect of elementary silver on osteoblast behaviour. Therefore, the prosthetic stem was not silver-coated because of concerns regarding a possible inhibition of the osseointegration. The aim of the present study was to investigate the effect of 5–25 mg of elementary silver in comparison to Ti-6Al-4V on human osteosarcoma cell lines (HOS-58, SAOS). Methods. Cell viability was determined by measuring the MTT proliferation rate. Cell function was studied by measuring alkaline phosphatase (AP) activity and osteocalcine production. Results. In the HOS-58 cells, the AP activity was statistically significant (P < 0.05) higher at a supplement of 5–10 mg of silver than of Ti-6 Al-4V at the same doses. For both cell lines, a supplement above 10 mg of silver resulted in a reduced AP activity in comparision to the Ti-6 Al-4V group, but a statistically significant difference (P < 0.05) was observed at a dose of 25 mg for the SAOS cells only. At doses of 20–25 mg in the HOS-58 cells and 10–25 mg in the SAOS cells, the reduction of the proliferation rate by silver was statistically significant (P < 0.05) compared to the Ti-6 Al-4V supplement. Discussion. In conclusion, elementary silver exhibits no cytotoxicity at low concentrations. In contrast, it seems to be superior to Ti-6 Al-4V concerning the stimulation of osteogenic maturation at these concentrations, whereas at higher doses it causes the known cytotoxic properties.

Massive allografts in tumour surgery

We offer our personal experience of the use of massive bone allografts after tumour resection. We demonstrate the long-term results from 71 patients (72 allografts) operated on between 1961 and 1990. The long-term survival rate in osteoarticular and intercalary grafts is around 60%. Fractures of the graft can be salvaged in most cases. Infection leads to the removal of the graft in almost all cases. Factors influencing the survival, remodelling and complications of the grafts are discussed. The regime of cryopreservation, fixation and loading of the graft influence these factors, as do the use of autologous bone chips around the allograft-host junction and the application of chemotherapy or radiation. Fracture of the graft can be salvaged in most cases, as opposed to infection which remains the most severe complication and can occur at any time. Even with the improvement of tumour endoprostheses, the use of allografts remains an option, especially in young patients.

Aseptic Loosening is Uncommon with Uncemented Proximal Tibia Tumor Prostheses

Aseptic loosening is a frequent cause of failure of cemented proximal tibia tumor endoprostheses. Uncemented prostheses may lessen this risk. We identified complications including aseptic loosening that affected prosthetic survival, limb survival and functional outcome for 44 consecutive patients after sarcoma resection from the proximal tibia and uncemented endoprosthetic reconstruction. At a mean final followup of 60 months (range, 9-152 months), there were no cases of aseptic loosening. Twelve (27%) patients suffered 14 complications leading to prosthetic failure due to infection (n = 7), stem fracture (n = 2), rotational instability (n = 1), vascular compromise (n = 2) and local tumor relapse (n = 2). However, limb salvage was successful in 37 of 44 (84%) patients. Functional assessment for 35 patients revealed a mean Toronto Extremity Salvage Score of 77/100 (range, 33-98) and Musculoskeletal Tumor Society 1987 and 1993 scores of 25/35 (range, 13-31) and 75/100 (range, 33-97), respectively. Mean knee joint flexion was 91 degrees (range, 0-110 degrees ) and knee extension lag was 6 degrees (range, 0-30 degrees ). Three patients with knee extensor complications had inferior functional outcomes. Aseptic loosening is uncommon with uncemented proximal tibia reconstruction, but decreasing other complications at this location remains challenging. Therapeutic study, level IV-1 (case series).

Characteristics and outcome of infections associated with tumor endoprostheses

Infection associated with prosthesis used after tumor resection is a common and serious complication. The purpose of the current retrospective study was to describe the course of infection in patients with a tumor endoprosthesis and the determination of risk factors associated with failed limb salvage. 30 patients with an infection associated with a tumor endoprosthesis were investigated with regard to treatment strategies, number and type of revision operations, duration of hospital stay, determination of risk factors associated with failed limb salvage and final outcome. Limb salvage related to the complication infection was achieved in 19 patients (63.3%). Two-stage reimplantation of an endoprosthesis was successful in 14 patients but subsequently failed in one patient. Out of 11 patients where limb salvage failed, an amputation was performed in 6 patients, a rotationplasty in 4, and stump lengthening procedure in 1 patient. A poor soft tissue condition was a significant (P<0.05) risk factor for failed limb salvage. No patient receiving chemotherapy with a poor soft tissue condition had limb salvage surgery. The mean number of revision operations per patients was 2.6. The mean duration of hospital stay was 68 days. Infection associated with prosthesis is a serious complication and is involved with long hospitalization. Limb salvage failed mostly in the case of a poor soft tissue condition. In these cases repeated revision surgery should be avoided and ablative surgery recommended at an early stage. Rotationplasty is an alternative to amputation in the case of an infection of the proximal or distal part of the femur.

Biomechanical aspects of revision components for knee arthroplasty

Total knee arthroplasty (TKA) is one of the most frequent orthopaedic surgical procedures. Despite continuous improvements in the endoprostheses, instruments, and operative techniques, revision TKA has a rate of about 10% of overall TKA. In addition to the restoration of the periprosthetic bone stock and a precise alignment, the choice of an adequate implant, which meets the patient's specific requirements, has high impact on the outcome. The most significant differences between implants involve the degree of reconstructed joint area (uni-, bi-, tri-compartimental) and the order of the constraining forces between the femoral and tibial component. Implants for revision TKA commonly range from un- or semiconstrained resurfacing implants to fully constrained hinged endoprostheses. In case of severe osseous, ligamentous, and/or muscular defects, special tumor endoprostheses or implants for arthrodesis might be an alternative option.

Uncemented Tumor Endoprostheses at the Knee: Root Causes of Failure

Uncemented Tumor Endoprostheses at the Knee: Root Causes of Failure

Uncemented Tumor Endoprostheses at the Knee

Although cemented tumor endoprostheses are the most commonly used method for reconstruction of the distal femur or proximal tibia after resection of primary bone tumors, aseptic loosening remains a common complication. Uncemented tumor prostheses may minimize this problem. We investigated the root causes of prosthetic failure for 99 patients with a fixed-hinge, bone-ingrowth Kotz Modular Femur and Tibia Resection System endoprosthesis and compared complications that led to implant failure with results in the literature. Of the 74 distal femoral implants and 25 proximal tibial implants, 25 patients had complications that resulted in prosthetic failure (removal of the prosthesis) at a median of 24.1 (range, 0.8-72.6) months. Failure was caused by prosthesis (n = 18) or oncologic-related (n = 7) complications. However, limb-salvage was possible for 87 of 99 patients. Smaller stem size in the distal femur and longer bone resection length in the proximal tibia were significantly associated with increased risk of prosthetic failure by multivariate analysis. The risk of stem fracture (6 of 99 patients) and infection (10 of 99 patients) was higher than other reports, but aseptic loosening (2 of 99 patients) was uncommon. These results suggest that although the bone-ingrowth surface of this prosthesis leads to a very low aseptic loosening rate, the higher risk of stem fracture and infection must be addressed in future implant designs. Therapeutic study, level IV-1 (case series).

Endoprosthetic replacement of the humerus combined with trapezius and latissimus dorsi transfer: a report of three patients

To improve the functional outcome after proximal and/or total humerus replacement, we combined the surgical procedures described by Bateman and Gerber. In three patients after wide tumor resection, endoprosthetic replacement with a modular tumor endoprosthesis (MUTARS System) was performed. In addition to a capsular and muscular reconstruction using the Trevira tube, a trapezius transfer onto the Trevira tube in combination with a latissimus dorsi transfer onto the Trevira tube was performed. The patients were immobilized for 6 weeks after surgery with an abductor cast. After a follow-up of 1 year, there was no significant improvement of the shoulder function in comparison with patients who did not undergo the combined muscle transfer (control group n=16: mean abduction 37.5 degrees ; mean anteversion 35.0 degrees ; mean internal rotation 15.2 degrees ; mean external rotation 25.2 degrees ). In our patients, the combination of the Gerber and the Bateman procedures did not improve the shoulder function in patients with proximal and/or total humerus replacements. Therefore, the functional results do not justify two separate approaches and a prolonged operation time.

Limb salvage with tumor endoprostheses for malignant tumors of the knee.

Data of 64 consecutive patients with malignant tumors of the knee treated with tumor endoprostheses between 1976 and 1996 were reviewed. The study was retrospective before 1990 and prospective since then. Four patients were lost to followup and are not included in the study. The average age of the remaining 60 patients was 33.2 years (range, 9-72 years). Fifty patients had surgery for primary sarcoma and 10 patients had surgery for metastases of carcinoma. In the patients in the sarcoma group, the probability of 5 years survival was 72% and 10 years survival was 69%. The overall clinical score of 47 patients with a followup more than 9 months was 81% using the evaluation system of the International Society of Limb Salvage. Fifty-eight reoperations were done in 29 patients because of complications. Twenty reoperations were attributable to soft tissue complications, 34 reoperations were because of mechanical problems related to the prostheses, and four were because of local tumor recurrence. The probability of survival of the leg of the patient after 10 years was 95%. Despite a high rate of complications after limb salvage with endoprostheses, the final clinical outcome usually was good.

Revision of the Kotz type of tumour endoprosthesis for the lower limb

Revision of the Kotz type of tumour endoprosthesis for the lower limb

Revision of the Kotz type of tumour endoprosthesis for the lower limb

In 251 patients over a period of 15 years an uncemented Kotz modular femoral and tibial reconstruction mega prosthesis was implanted after resection of a malignant tumour of the lower limb. Twenty-one patients (8.4%) underwent revision for aseptic loosening, again using an uncemented prosthesis, and five of these required a further revision procedure. The median follow-up time from the first revision was 60 months (11 to 168) and after a second revision, 33 months (2 to 50). The probability of a patient avoiding aseptic loosening for ten years was 96% for a proximal femoral, 76% for a distal femoral and 85% for a proximal tibial implant. At the time of follow-up all radiographs were assessed according to the International Symposium of Limb Salvage criteria. The first radiological signs of aseptic loosening were always seen at the most proximal or distal part of the anchorage stem at a mean of 12 months (4 to 23) after the first implantation. Using the Musculoskeletal Tumor Society score for evaluation, the clinical results showed a mean of 88% of normal function.

Revision of the Kotz type of tumour endoprosthesis for the lower limb.

In 251 patients over a period of 15 years an uncemented Kotz modular femoral and tibial reconstruction mega prosthesis was implanted after resection of a malignant tumour of the lower limb. Twenty-one patients (8.4%) underwent revision for aseptic loosening, again using an uncemented prosthesis, and five of these required a further revision procedure. The median follow-up time from the first revision was 60 months (11 to 168) and after a second revision, 33 months (2 to 50). The probability of a patient avoiding aseptic loosening for ten years was 96% for a proximal femoral, 76% for a distal femoral and 85% for a proximal tibial implant. At the time of follow-up all radiographs were assessed according to the International Symposium of Limb Salvage criteria. The first radiological signs of aseptic loosening were always seen at the most proximal or distal part of the anchorage stem at a mean of 12 months (4 to 23) after the first implantation. Using the Musculoskeletal Tumor Society score for evaluation, the clinical results showed a mean of 88% of normal function.

Bone defects in revision total knee arthroplasty: classification and management

The goal of bone reconstruction in revision total knee arthroplasty is to provide a stable support for the implant and to re-establish the correct joint line. Therefore, a useful, therapy-based classification of the defects is necessary. According to Stockley et al. (1992), the defects are classified into contained and uncontained defects. Uncontained defects can be reconstructed using structural allografts or metal wedges. In contained defects, cancellous allograft can be used. For aseptic loosening of total knee arthroplasty, the defect classification according to Engh and Parks (1994) can be helpful because of its recommendations for reconstruction. In case of the more common first or second graded defects, reconstruction is performed using modular revision components or allografts. For the rare third graded defects, bulk allografts or modular tumour endoprostheses are recommended. On the basis of more than 150 revision total knee arthroplasties performed in our hospital the classification of bone defects and their clinical consequences are presented in this review.