[The MyKnee® patient-specific system. Rationale, Technique and Results]. / Das Patientenspezifische MyKnee®-Instrumentarium. Hintergründe, Technik und Ergebnisse.

BACKGROUND: Adequate three-dimensional component positioning and restoration of overall limb alignment are primary goals in total knee arthroplasty. Patient-specific instrumentation (PSI) is a potential way to improve accuracy of knee reconstruction surgery. However, currently available literature regarding the reliability of PSI shows inconsistent results for limb alignment restoration and component positioning. OBJECTIVES: The purpose of this article is to illustrate the rationale for using PSI in total knee arthroplasty, to demonstrate the surgical technique, and to present our outcome with the MyKnee(®) system. METHODS: We illustrate in detail the logistics and workflow involved in PSI for total knee arthroplasty. Finally, we present clinical and radiological results of patients undergoing knee arthroplasty using the MyKnee(®) system compared to a conventional instrumentation group. RESULTS: PSI significantly improved accuracy and reduced the number of outliers regarding neutral mechanical alignment restoration as well as three-dimensional component positioning compared to conventional instrumentation. The early clinical outcome was comparable between the two instrumentation groups. However, clinical outcome in the subgroup of patients within ± 3° from neutral mechanical limb alignment was superior to limb alignment outliers. CONCLUSION: The MyKnee(®) PSI system presents a reliable way to improve the accuracy of mechanical limb alignment restoration and three-dimensional component positioning in total knee arthroplasty. Nonetheless, an adequate surgical technique remains the crucial factor for successful total knee reconstruction.

[Prevention of heterotopic ossification after THA with indomethacin: analysis of risk factors]. / Ossifikationsprophylaxe nach Hüft-TEP mit Indomethacin: Analyse von Risikofaktoren.

AIM: Several risk factors are associated with heterotopic bone formation following total hip replacement. All these risk factors were defined in cohorts without any treatment against postoperative ectopic bone. The aim of this prospective study was to reveal risk factors for the development of postoperative ossifications in patients who underwent a 7-day course of indomethacin therapy. METHODS: 211 consecutive patients with 217 cementless total hip arthroplasties were included. Patients were given 100 mg indomethacin daily in a 7-day course. RESULTS: Grade 2 or 3 ossifications were observed in 13 (5%) of the male and 3 (2%) of the female Individuals postoperatively (p = 0.0043; odds ratio = 0.45). Older individuals (p = 0.0021; odds ratio = 1.03) as well as patients with primary osteoarthritis (p = 0.0307; odds ratio = 0.28) also showed a higher risk for developing ectopic bone formations. CONCLUSION: With a 7-day course of indomethacin after total hip arthroplasty, male and elderly individuals, as well as patients with primary osteoarthritis, are considered to be at high risk to develop heterotopic ossifications postoperatively. Indomethacin reduces the incidence of postoperative ectopic ossifications, but not the patient's risk.

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.

Growth prediction in extendable tumor prostheses in children.

Limb salvage procedures for malignant bone tumors of the lower limb in children usualy involve resection of at least one growing physis. To achieve equal leg length, reconstruction relies on accurate prediction of the remaining growth potential of the child. The current authors present the results of predicted growth versus actual prosthetic elongation observed in a group of 15 children fitted with extendable tumor endoprostheses of the lower limb who subsequently have reached skeletal maturity. All patients had at least one of the distal femoral or proximal tibial physes resected for a primary malignant bone tumor. Eight patients underwent distal femoral resection, four patients underwent proximal tibial resection, and three patients had total resection of the femur. All patients received custom-made Howmedica extendable prostheses. In two patients, a newly developed automatic elongation module was used. At followup, between 70 and 158 months, the patients achieved a mean elongation of the surgically treated limb of 10.4 cm (range, 1.1-19.5 cm), which exceeded the predicted growth by 24.3%. Final leg length discrepancies did not exceed 1 cm. Using incremental extendable tumor endoprostheses, individual adaptation of the elongation procedures could be achieved for equalization of leg length discrepancies in children after resection of primary malignant bone tumors of the lower limb.

[Diagnostic-therapeutic procedure in benign bone tumors]. / Diagnostisch-therapeutisches Vorgehen bei gutartigen Knochentumoren.

The indications of surgical treatment of benign bone tumours are strongly related to the clinical behaviour, the patient's complaints and the activity in Tc-bone scan. Some lesions--like the nonossifying fibroma--that can safely be diagnosed by conventional x-rays may not be treated surgically--as long as the patients are free of pain, and there is no risk of pathologic fracture. In case of clinically relevant lesions, activity in Tc-bone scan, or a risk of fracture, biopsy and curettage combined with autologous or homologous bone grafting is indicated. Some aggressive tumors, like the giant cell tumor, have to be treated more aggressively by curettage with adjuvant measures (Phenole) or by marginal excision.

Long-term followup of uncemented tumor endoprostheses for the lower extremity.

Between 1982 and 1989, 100 primary lower limb reconstructions were done using the Kotz Modular Femur Tibia Reconstruction System after resection of a malignant tumor. In 32 patients a proximal femur prosthesis was implanted, in 40 patients a distal femur prosthesis was implanted, in 19 patients a proximal tibia component was implanted, in four patients a total femur prosthesis was implanted, and in five patients a total knee prosthesis was implanted. The Kaplan-Meier estimate of the overall survival rate of the prostheses was 85% after 3 years, 79% after 5 years, and 71% after 10 years. The most common reason for implant failure was aseptic loosening in 27% of patients (11 patients; range, 10-121 months) after the initial operation. The other reasons for revision surgery were implant fracture (n 5 4) and infection (n 5 4). Early repair of prostheses-related minor complications, such as worn polyethylene bushings, resulted in a statistically significant reduction of implant failure. After a median followup of 127.5 months after the initial surgery, 51 patients had died and eight patients were lost to followup. Forty-one patients were evaluated clinically and radiologically using the Musculoskeletal Tumor Society score and the radiologic implant evaluation system of the International Symposium on Limb Salvage; these 41 patients had a mean of 80% (range, 40%-100%) of the normal functional capability.

Radiation synovectomy using 165Dy ferric-hydroxide and oxidative DNA damage in patients with different types of arthritis.

UNLABELLED: Radiation synovectomy is an effective treatment for chronic synovitis refractory to pharmacological treatment in patients with rheumatoid or seronegative arthritis. Concerns persist about possible radiation-induced cytogenetic damage after radiation synovectomy leading to recommendations to use this technique only in the elderly. Micronucleus (MN) frequency in lymphocytes and urinary excretion of 8-hydroxy-2'-deoxyguanosine (8OHdG) as an indicator of cellular oxidative DNA base damage are biomarkers of radiation-induced cytogenetic damage. The course of both biomarkers was studied in patients with different types of chronic synovitis undergoing radiation synovectomy with very short-lived 165Dy-ferric-hydroxide (DFH). METHODS: Radiation synovectomy of the knee was performed in 13 men and 12 women (mean age, 44+/-15 y) using a mean activity of 9.48+/-1.65 GBq 165Dy-DFH in 27 consecutive treatments. MN frequency in lymphocytes and urinary excretion of 8OHdG, measured by high-performance liquid chromatography, were assessed before and 4 (MN only) and 20 h after radiation synovectomy. RESULTS: Urinary excretion of 8OHdG in patients (in micromol/mol creatinine; pretreatment mean, 3.1+/-3.4; median, 2.27) was not significantly different from that in healthy volunteers (mean, 2.0+/-1.2; median, 1.87) and not altered by radiation synovectomy (post-treatment mean, 2.5+/-1.5; median, 2.04, NS). An increase in 8OHdG levels after radiation synovectomy of more than 1 SD was found in only 1 patient, who experienced leakage to the lymph nodes but who already had elevated urinary 8OHdG levels before treatment. The frequency of MN/500 binucleated cells (BNCs) was slightly lower in patients (pretreatment mean, 4.3+/-2.6; median, 4.25) than in healthy volunteers (mean, 5.4+/-2.3; median, 5.3) and did not significantly change after therapy, either (4-h post-treatment mean, 3.9+/-2.1, median, 3.8; 20-h post-treatment mean, 4.1+/-2, median 3.8 MN/500 BNC). In 22 of 27 treatments, no leakage to nontarget organs could be monitored, whereas leakage to the local lymph nodes and the liver was detected after 5 treatments. CONCLUSION: Radiation synovectomy using 165Dy-DFH causes no significant radiation burden to most patients as indicated by the absence of adverse changes in levels of biomarkers of cytogenetic damage and a low incidence of leakage. These data suggest that the risk of malignancy may not be elevated.

Intensified Adjuvant IFADIC Chemotherapy for Adult Soft Tissue Sarcoma: A Prospective Randomized Feasibility Trial.

Purpose. The present prospective randomized adjuvant trial was carried out to compare the toxicity, feasibility and efficacy of augmented chemotherapy added to hyperfractionated accelerated radiotherapy after wide or marginal resection of grade 2 and grade 3 soft tissue sarcoma (STS).Patients and methods. Fifty-nine patients underwent primary surgery by wide or marginal excision and were subsequently randomized to receive radiotherapy alone or under the addition of six courses of ifosfamide (1500 mg/m(2) , days 1-4), dacarbazine (DTIC) (200 mg/m(2) , days 1-4) and doxorubicin (25 mg/m(2) , days 1-2) administered in 14-day-intervals supported by granulocyte-colony stimulating factor (30 x 10(6) IU/day, s.c.) on days 5-13. According to the randomization protocol, 28 patients received radiotherapy only, whereas 31 patients were treated with additional chemotherapy.Results. The relative ifosfamide-doxorubicin-DTIC (IFADIC) dose intensity achieved was 93%. After a mean observation period of 41+/-19.7 months (range, 8.1-84 months), 16 patients (57%) in the control group versus 24 patients (77%) in the chemotherapy group were free of disease (p>0.05).Within the control group, tumor relapses occurred in 12 patients (43%;six patients with distant metastases, two with local relapse, four with both) versus seven patients (23%; five patients with distant metastases, one with local recurrence, one with both) from the chemotherapy group. Relapse-free survival (RFS) (p=0.1), time to local failure (TLF) (p=0.09), time to distant failure (TDF) (p=0.17) as well as overall survival (OS) (p=0.4) did not differ significantly between the two treatment groups. Treatment-related toxicity was generally mild in both treatment arms.Conclusion. We conclude that the safety profile of intensified IFADIC added to radiotherapy was manageable and tolerable in the current setting. Inclusion of intensified IFADIC was not translated into a significant benefit concerning OS, RFS, TLF andTDF as compared with radiotherapy only, although a potential benefit of chemotherapy for grade 3 STS patients needs to be validated in prospective randomized trials including larger patient numbers.

[Early weight bearing after uncemented total hip prostheses--an analysis of acetabulum cup migration]. / Frühzeitige Belastung nach zementfreien Hüfttotalendoprothesen--Eine Pfannenmigrationsanalyse.

PURPOSE: The postoperative mobilisation after cementless total hip arthroplasty is usually non-weight bearing within the first six weeks to achieve bony ingrowth for the implant. Since 1995 weight bearing mobilisation is performed at our clinic even after cementless implantation of the Alloclassic (Zweymüller-Sulzer) system. The aim of the presented study was the detection of any negative influence of weight bearing mobilisation on the stability of this cementless implant. METHOD: The horizontal and vertical cup migration of 42 cementless acetabular cups (Alloclassic Zweymüller-Sulzer) in 40 patients after weight bearing mobilisation and a minimum follow up of 24 months were analysed by a digital migration analysis. The results were compared to a normative migration profile of the same that was recently established. RESULTS: The migration analysis did not exceed the level of accuracy of 1.3 mm in any patient. The mean horizontal cup migration was 0.3 mm in both groups after 24 months, the mean vertical migration was 0.4 mm in both groups. No significant difference of the acetabular stability was detectable. None of the implants showed radiological signs of loosening or migration. CONCLUSION: The presented data justify an early postoperative weight bearing mobilisation using the cementless Alloclassic threated cup, provided that primary stability of the implant can be achieved.

Influence of radiation synovectomy on articular cartilage, synovial thickness and enhancement as evidenced by MRI in patients with chronic synovitis.

UNLABELLED: Radiation synovectomy is a safe and effective treatment for chronic synovitis that is refractory to the repetitive, intra-articular application of glucocorticosteroids in patients with rheumatoid or seronegative arthritis. Short-term and long-term effects of radiation synovectomy on articular cartilage, synovial enhancement and thickness were assessed in a prospective, clinical trial by MRI. METHODS: Thirteen patients (mean age 39+/-13 y) were treated with a median activity of 8.4 GBq 165Dy ferric hydroxide, a radionuclide with favorable physical properties and a well-documented clinical safety and efficacy profile. MRI was performed on a 1.5-T MR unit using a circular polarized knee coil. RESULTS: After a mean observation period of 13 mo, a marked reduction in synovial enhancement was observed in 10 patients. The mean reduction in baseline synovial thickness (mean 7.6+/-3.0 mm) was 24% (P = 0.03) at 1 wk and 42% (P = 0.01) about 1 y after treatment, respectively. Clinically, 9 of 13 patients (69%) exhibited persistent response to radiation synovectomy. The local clinical score, as defined by the reduction in pain, pannus, joint effusion and by the increase in the range of motion, improved significantly (P = 0.01), from a median of 7 (range 4-10) to a median of 2 (range 0-9). One year after treatment, changes in the local clinical score were related to the decrease in synovial enhancement in MRI (r = 0.7, P = 0.008, n = 12). There were no persistent adverse effects, nor was there evidence for any severe radiation-induced damage to the articular cartilage. On later follow-up images, the structure of the articular cartilage remained unaltered in all but 3 patients, who had new, superficial erosions most likely attributed to an active disease with persistence of inflammation. CONCLUSION: This study suggests that radiation synovectomy with 165Dy-ferric hydroxide is effective in terms of reducing chronic synovitis without causing detectable harm to the articular cartilage, as shown by MRI.

Six-year results of a cementless stem with prophylaxis against heterotopic bone.

The hypothesis of a possibly diminished bony ingrowth revealed by the development of radiolucency or a radiodense line with time around a cementless femoral stem subsequent to indomethacin administration for prevention of heterotopic ossification was investigated. Eighty prospective patients with indomethacin prophylaxis were compared with 82 patients without indomethacin prophylaxis chosen retrospectively. The same cementless implant was used in all cases, and patients were observed clinically and radiologically for a minimum of 6 years. The mean postoperative Harris hip score at 6 years was 91 versus 88 points, respectively, and there were significantly more excellent results (Harris hip score > 90) in the indomethacin group. None of the patients underwent revision surgery. Radiologic signs such as loss of bone density and radiodense lines were observed around the shoulder of the prosthesis in a similar percentage in both groups. Significant subsidence of the stem was observed in one instance in the indomethacin group and in three instances in the control group. The results of this study are a strong indication that indomethacin does not influence the development of radiolucency or other radiologic changes around a cementless stem after 6 years.

Teicoplanin in the prevention of infection in total hip replacement.

Perioperative antibiotic prophylaxis has been shown to be effective in reducing postoperative wound infections. The rising incidence of infections secondary to methicillin-resistant strains of Staphylococcus aureus. S. epidermidis and S. enterococcal prompted us to administer Teicoplanin to infection in elective total joint arthroplasty. In 111 patients Teicoplanin was given in a single intravenous dose of 10 mg/kg prior to surgery. In the postoperative period no deep infection of the prosthetic device was found in a 14-month follow-up. In two patients the following organisms were isolated from superficial infections of the wound: S. epidermidis (methicillin-sensitive), Pseudomonas aeruginosa, and Enterobacter sp. In no patient was revision surgery necessary. The serum concentration of Teicoplanin was within the therapeutic range during surgery, and tissue levels of Teicoplanin in cancellous (6.2 mg/kg, range 3.8-10.9 mg/kg) and cortical (7.1 mg/kg, range 2.6-12.1 mg/kg) bone during surgery in 16 patients exceeded the minimum inhibitory concentration of 90% (MIC90) of methicillin-resistant strains reported for methicillin-resistant strains. In our experience a single dose regimen of Teicoplanin is a safe and effective method of antibiotic prophylaxis in hip joint replacement, particularly when methicillin-resistant bacteria are present.

[Surgical therapy of spinal metastases]. / Operative Therapie von Wirbelsäulenmetastasen.

Bone metastases of the vertebral spine occur frequently after breast cancer, hypernephroma or thyroid carcinoma. Located commonly in the lumbar and thoracic spine, half of the lesions are found in the vertebral body, but in many cases lamina and pedicles are also involved. Pain resistant to conservative treatment, vertebral compression fracture and segmental instability, together with progredient neurologic deficits and para- or tetraplegia, all make operative intervention mandatory. In this article dorsal decompression and stabilization are compared to ventral decompression and compound osteosynthesis. Segmental stability and life-time prognosis of the patient are important factors to decide on the best surgical procedure. Dorsal decompression without stabilization should only be performed as a palliative procedure in patients with an inoperative tumor, poor prognosis, or if the estimated postoperative segmental stability seems to be sufficient. In cases of a solitary metastasis, after radical resection of the primary tumor and when the prognosis is good total vertebrectomy can be performed. In addition to surgical treatment, adjuvant chemotherapy and/or radiation therapy should be performed in a multidisciplinary setting.

Management of serious staphylococcal infections in the outpatient setting.

Patients with serious staphylococcal infections, e.g. endocarditis and osteomyelitis, need prompt and prolonged parenteral antibiotic treatment to ensure eradication of the causative pathogen. The major cost in the treatment of these infections is the long period of hospitalisation required for the administration of intravenous antibiotics. To shorten the hospitalisation period, outpatient treatment can be given to some patients. In this study, patients with acute exacerbations of chronic osteomyelitis (n = 44) or endocarditis (n = 10) were treated with intravenous teicoplanin. The pathogens were Staphylococcus aureus (n = 41, 13 of which were methicillin resistant) and coagulase-negative staphylococci (n = 13, one of which was methicillin resistant). After a mean loading dose of 15 mg/kg for 3 to 10 days, patients received teicoplanin 3 times a week at a dose (mean 15 mg/kg) individualised to achieve serum trough concentrations of approximately 10 mg/L for osteomyelitis and 20 mg/L for endocarditis. Treatment duration ranged from 28 to 150 (mean 62) days for patients with osteomyelitis and from 28 to 88 (mean 49) days for patients with endocarditis. 37 (84%) patients with osteomyelitis and 8 (80%) patients with endocarditis were treated successfully. Adverse events were observed in 9 patients and included rash (n = 3), thrombocytopenia (n = 3), and drug fever, pseudomembranous colitis, nausea, leucopenia and transient hearing impairment (one patient each). In conclusion, this study demonstrates that teicoplanin can be administered successfully in an outpatient setting according to a 3-times weekly schedule for the treatment of patients with staphylococcal osteomyelitis and endocarditis.

[Osteomyelitis. Clinical aspects, diagnosis and therapy]. / Osteomyelitis. Klinik, Diagnose und Therapie.

In this paper the basic features of acute, subacute and chronic types of osteomyelitis, skeletal tuberculosis and some special forms of osteomyelitis are described. The diagnosis of osteomyelitis is established using clinical signs and symptoms, culture studies, laboratory studies and radiological signs. The common conservative and surgical treatments are discussed. In the treatment of posttraumatic/postoperative osteitis severe problems are encountered as a result of an increasing number of orthopaedic traumatologic surgical techniques using a variety of implants and because of a generally increasing occurrence of multiresistant strains. Thanks to modern treatment and the increased use of antibiotics, a considerable decrease in morbidity and mortality is observed. Despite this improved prognosis, an established infection remains one of the most challenging problems for the orthopaedic surgeon.

Prevention of chemotherapy-induced anemia by the use of erythropoietin in patients with primary malignant bone tumors (a double-blind, randomized, phase III study).

BACKGROUND: Patients undergoing chemotherapy for treatment of malignancy frequently experience clinically significant anemia. Myelosuppressive chemotherapy impairs erythropoiesis, which may not fully recover between treatment cycles. Recombinant human erythropoietin (rHuEPO) has been effectively introduced in anemic patients suffering from chronic renal failure. The present study was designed to assess, first, whether rHuEPO treatment decreases transfusion requirements in chemotherapy-induced anemia and, second, whether high-dose rHuEPO application is safe. STUDY DESIGN AND METHODS: Thirty consecutive anemic patients (hemoglobin <11 g/dl) receiving combination chemotherapy for primary malignant bone tumors were studied in a prospective, double-blind, randomized, Phase III trial. Patients received chemotherapy according to one of two German protocols, depending on histologic diagnosis. All subjects enrolled were randomly assigned either to receive 600 IU of rHuEPO per kg of body weight intravenously twice a week or to receive a placebo during chemotherapy. To obtain comparable data, an observation period of 20 weeks was chosen. Twenty-nine patients fulfilled the criteria and were eligible for statistical evaluation. RESULTS: Transfusion requirements were significantly decreased from Week 8 of therapy (p<0.05) in the treatment group. Therapeutic benefits were even more evident with continuation of therapy (Week 12, p = 0.03; Week 16, p = 0.016; Week 20, p = 0.002). The blood required was 2.1 units of red cells in the treatment group and 8.4 units of red cells in the placebo group. All patients tolerated rHuEPO with no serious side effects. CONCLUSION: These findings suggest that rHuEPO is an effective and well-tolerated therapeutic option for decreasing the transfusion requirements in chemotherapy-induced anemia.