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PURPOSE: Considering the discrepant results of the recent biomechanical studies, the purpose of this study was to simulate dynamic muscle-loaded knee flexion with a large number of specimens and to analyse the influence of total knee arthroplasty (TKA) without and with patellar resurfacing on the patellofemoral pressure distribution. METHODS: In 22 cadaver knee specimens, dynamic muscle-loaded knee flexion (15°-90°) was simulated with a specially developed knee simulator applying variable muscle forces on the quadriceps muscles to maintain a constant ankle force. Patellofemoral pressures were measured with flexible, pressure-sensitive sensor foils (TEKSCAN) and patellofemoral offset with an ultrasound motion-tracking system (ZEBRIS). Measurements were taken on the native knee, after total knee arthroplasty and after patellar resurfacing. Correct positioning of the patellar implant was examined radiologically. RESULTS: The maximal patellofemoral peak pressure partly increased from the native knee to the knee with TKA with intact patella (35°-90°, p < 0.012) and highly increased (twofold to threefold) after patellar resurfacing (20°-90°, p < 0.001). Concurrently, the patellofemoral contact area decreased and changed from a wide area distribution in the native knee, to a punctate area after TKA with intact patella and a line-shaped area after patellar resurfacing. Patellar resurfacing led to no increase in patellar thickness and patellofemoral offset. CONCLUSIONS: Despite correct implantation of the patellar implants and largely unchanged patellofemoral offset, a highly significant increase in pressure after patellar resurfacing was measured. Therefore, from a biomechanical point of view, the preservation of the native patella seems reasonable if there is no higher grade patellar cartilage damage.
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Artroplastia do Joelho/métodos , Patela/cirurgia , Articulação Patelofemoral/fisiologia , Idoso , Idoso de 80 Anos ou mais , Artroplastia do Joelho/instrumentação , Fenômenos Biomecânicos , Humanos , Técnicas In Vitro , Prótese do Joelho , Modelos Anatômicos , Articulação Patelofemoral/cirurgia , Pressão , Amplitude de Movimento Articular/fisiologia , Suporte de CargaRESUMO
BACKGROUND: Most modern spinal implants contain titanium and remain in the patient's body permanently. Local and systemic effects such as tissue necrosis, osteolysis and malignant cell transformation caused by implants have been described. Increasing tissue concentration and whole blood levels of ions are necessary before a disease caused by a contaminant develops. The aim of the present study was the measurement of whole blood titanium levels and the evaluation of a possible correlation between these changes and the number of fused segments. METHODS: A prospective study was designed to determine changes in whole blood titanium levels after spinal fusion and to analyze the correlation to the number of pedicle screws, cross connectors and interbody devices implanted.Blood samples were taken preoperatively in group I (n = 15), on the first, second and 10th day postoperatively, as well as 3 and 12 months after surgery.Group II (n = 16) served as a control group of volunteers who did not have any metal implants in the body. Blood samples were taken once in this group.The number of screw-rod-connections and the length of the spinal fusion were determined using radiographic pictures. This study was checked and approved by the ethical committee of the University of Tuebingen. RESULTS: The mean age in group I was 47 ± 22 years (range 16 - 85 years). There were three male (20%) and twelve female (80%) patients. The median number of fused segments was 5 (range 1 to 11 segments).No statistically significant increase in the titanium level was seen 12 months after surgery (mean difference: -7.2 µg/l, 95% CI: -26.9 to 12.5 µg/l, p = 0.446). By observing the individual titanium levels, 4 out of 15 patients demonstrated an increase in titanium levels 12 months after surgery.No statistically significant correlation between fused segments (r = -0.188, p = 0.503) length of instrumentation (r = -0.329, p = 0.231), number of interbody devices (r = -0.202, p = 0.291) and increase of titanium levels over the observation period was seen. CONCLUSIONS: Instrumented spinal fusion does not lead to a statistically significant increase in whole blood titanium levels. There seems to be no correlation between the number of pedicle screws, cross connectors and interbody devices implanted and the increase of serum titanium levels.
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Parafusos Ósseos , Fusão Vertebral/instrumentação , Titânio/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Estudos de Casos e Controles , Feminino , Alemanha , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Desenho de Prótese , Fusão Vertebral/efeitos adversos , Fatores de Tempo , Resultado do Tratamento , Adulto JovemRESUMO
BACKGROUND: Targeted infiltrations to the lumbar spine are used to identify the correct scope for surgery in patients with chronic lumbar back pain (CLBP) and multi-segmental pathologies, where radiologic imaging and clinical presentation do not match. Conclusions from that method have so far been based on individual statements of pain relief. The main principle for the infiltrations is the assumption that by locally administering an analgesic agent to possible surgical target areas, the effect of surgery can be temporarily simulated. The aim was to investigate the use of rasterstereographic posture measurements to substantiate reported pain reduction after infiltrations. METHODS: In this case-control study (Level II), rasterstereography was performed on 57 patients and 28 reference subjects to evaluate changes in posture during 1 week of injections under fluoroscopic guidance and correlated with changes in the Numeric Pain Rating Scale (NRS). Statistical analysis was performed with SPSS (α = .05, two-sided) and presented in the form of box, scatter, and Bland-Altman plots. RESULTS AND CONCLUSION: The CLBP patients' trunk inclination (median 6°) and absolute lateral tilt were significantly increased (p < .01 each) compared to the reference group. No significant difference was observed for trunk length, kyphotic/lordotic angle, or lateral deviation. During infiltration, no significant difference in posture could be observed. A subgroup analysis of patients reporting the highest pain improvement indicated no significant difference. No correlation was observed with pain improvement reported by the patients during injections. Subsequent rasterstereography does not seem to be able to verify results of injections in the diagnostics of lumbar spine pathologies, as patients' reported pain relief does not correlate with a relevant alteration in posture. The short-term effect of the targeted infiltrations may not suffice to change false posture being developed over years.
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Dor Lombar , Vértebras Lombares , Dor nas Costas/tratamento farmacológico , Estudos de Casos e Controles , Humanos , Dor Lombar/diagnóstico por imagem , Dor Lombar/tratamento farmacológico , Vértebras Lombares/diagnóstico por imagem , PosturaRESUMO
The aim of our study is to evaluate clinical long-term results and determine changes in periprosthetic bone density of the custom-made hip prostheses Evolution-K ® and Adaptiva ® . Periprosthetic bone density were evaluated by means of DEXA (LunariDXA- Prodigy® bone densitometer) with a long-term follow-up of 16 (15-18) years (Evolution-K®) in 24 patients and 13 (13-15) years (Adaptiva®) in 41 patients. Evolution- K® had a survival rate of 92% and yielded 79/100 points in Harris Hip Score, a mediocre result. Adaptiva® had a survival rate of 99% and achieved a good score of 88/100 points. Bone density measurements demonstrated the greatest loss of bone density in the proximal regions of interest (ROI) for both prosthesis types (Evolution-K®: -25.8% ROI 1, -40.3% ROI 7; -8.3% ROI 2, -10.4% ROI 6; Adaptiva®: -29.8% ROI 7, -6.8% ROI 6, +14.3% ROI 3, +3.1% ROI 4). Adaptiva® yielded a good clinical result as compared to Evolution-K® with only average clinical results. Both prostheses clearly showed signs of "stress shielding". Here, the Adaptiva® achieved reduced bone density loss as compared to the Evolution-K®.
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BACKGROUND: Patients with chronic lumbar back pain (CLBP) often present with an altered gait profile, which is a crucial element of good functioning in everyday life. In patients with multisegmental spinal pathologies and incongruity between radiologic imaging and clinical presentation, inpatient gradual diagnostics (IGD) is performed to determine the precise origin of the disabling pain. The underlying principle of IGD is the assumption that by locally administering an analgesic and anti-inflammatory agent to possible surgical target areas, the surgical effect can be temporarily simulated. The conclusions drawn from IGD are, however, mostly based on the patients' subjective feedback about pain relief. RESEARCH QUESTION: The aim of this study was to evaluate whether reported pain relief during IGD can be objectified by gait analysis. We hypothesized that patients with greater pain relief during IGD would show greater improvement in their pathologic gait and stance. METHODS: Treadmill gait and stance analyses were prospectively performed on CLBP patients before and after a one-week IGD. Self-report measures included the numeric pain rating scale (NRS) and the Oswestry Disability Index (ODI). RESULTS AND SIGNIFICANCE: Compared with a reference group (nâ¯=â¯28), IGD patients (nâ¯=â¯57) at admission showed reduced velocity, cadence, step length, and swing phase (pâ¯<â¯.01 each). Their stance phase was increased by 5% of the gait cycle, and a more asymmetrical total load distribution during stance was observed. No difference was seen in stride width or foot rotation. While many patients reported good pain relief during IGD, no correlation was observed between subjective improvement and treadmill measures. We can thus confirm a pathologic gait profile in patients with CLBP. Based on our findings, gait analysis would not yet seem suitable to objectify IGD results. The short time interval between admission and discharge may not suffice to change a pathological gait that has developed over years.
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Marcha/fisiologia , Dor Lombar/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Anestésicos Locais , Anti-Inflamatórios , Dor nas Costas , Bupivacaína , Feminino , Análise da Marcha , Hospitalização , Humanos , Injeções Epidurais , Injeções Intra-Articulares , Dor Lombar/diagnóstico , Dor Lombar/tratamento farmacológico , Vértebras Lombares , Masculino , Pessoa de Meia-Idade , Medição da Dor , Autorrelato , Resultado do Tratamento , TriancinolonaRESUMO
Patients with Fontan circulation represent a significant cardiorespiratory risk during spinal surgery. We report about two patients with severe scoliosis and Fontan circulation and their successful operative treatment. The case report will be compared with the national and international literature.
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Cardiopatias Congênitas/complicações , Insuficiência Cardíaca/congênito , Procedimentos Neurocirúrgicos/métodos , Escoliose/complicações , Escoliose/cirurgia , Adolescente , Cianose/etiologia , Cianose/fisiopatologia , Cianose/cirurgia , Feminino , Cardiopatias Congênitas/fisiopatologia , Insuficiência Cardíaca/fisiopatologia , Humanos , Fixadores Internos/normas , Complicações Intraoperatórias/prevenção & controle , Monitorização Intraoperatória , Procedimentos Neurocirúrgicos/instrumentação , Radiografia , Procedimentos de Cirurgia Plástica/instrumentação , Procedimentos de Cirurgia Plástica/métodos , Insuficiência Respiratória/etiologia , Insuficiência Respiratória/patologia , Insuficiência Respiratória/fisiopatologia , Fatores de Risco , Escoliose/fisiopatologia , Fusão Vertebral/instrumentação , Fusão Vertebral/métodos , Coluna Vertebral/diagnóstico por imagem , Coluna Vertebral/patologia , Coluna Vertebral/cirurgia , Vértebras Torácicas/diagnóstico por imagem , Vértebras Torácicas/patologia , Vértebras Torácicas/cirurgia , Resultado do TratamentoRESUMO
OBJECTIVE: Total hip replacement with maximum preservation of femoral neck. Restoration of pain-free joint function. INDICATIONS: Coxarthrosis, femoral head necrosis in younger patients with intact femoral neck. CONTRAINDICATIONS: Joint infection. Coxa valga (caput-collum-diaphysis [CCD] angle > 150 degrees ). Coxa vara (CCD angle < 110 degrees ). Body mass index > 30 (relative contraindication). Ongoing chemotherapy. Osteoporosis. SURGICAL TECHNIQUE: Transgluteal or anterolateral approach. Resection of two thirds of the femoral head. Implantation of uncemented acetabular component. Revitalization of the femoral neck with special rasps for the CUT prosthesis. Trial reduction with bone rasp and modular cone in place (10 degrees or 20 degrees angle). Uncemented stem implantation. RESULTS: From 2002 to 2006, 49 uncemented CUT prostheses were implanted in 36 patients. Average age was 45.1 years (20-60 years). Inpatient stay amounted to 10.8 days and operating time to 74 min. Average blood loss through drainage was 795 ml, an average of 297 ml transfused back. Transfusion was necessary in ten patients. There were no cases of postoperative infection, nerve lesion, or hip dislocation. Patients were examined preoperatively and followed up at 6 weeks and 1 year. Harris Hip Score improved from 46.1 points preoperatively to 81.6 points at 6 weeks and 95.7 points at 1 year. Average leg length discrepancy of 0.7 cm (minimum -0.8, maximum 2.2 cm) was determined radiologically in 31 of 49 patients. It became necessary to replace two of the 49 stems due to aseptic loosening, in the first case at 19 months (femoral head osteonecrosis, lupus erythematosus, and taking cortisone), and in the second case 3 years after implantation (steroid-induced femoral head necrosis related to Crohn's disease and azathioprine [Imurek] therapy). One cone and head component had to be revised 1 month after implantation due to impingement syndrome. One ceramic head fractured 2.5 years after implantation so that cone and head required revision. The overall follow-up time was 37 months on average (minimum 12, maximum 55 months).
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Artroplastia de Quadril/métodos , Necrose da Cabeça do Fêmur/cirurgia , Colo do Fêmur/cirurgia , Prótese de Quadril , Osteoartrite do Quadril/cirurgia , Desenho de Prótese , Adulto , Artroplastia de Quadril/instrumentação , Feminino , Necrose da Cabeça do Fêmur/diagnóstico por imagem , Colo do Fêmur/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite do Quadril/diagnóstico por imagem , Cuidados Pós-Operatórios , Complicações Pós-Operatórias/diagnóstico por imagem , Complicações Pós-Operatórias/cirurgia , Falha de Prótese , Radiografia , Reoperação , Instrumentos CirúrgicosRESUMO
OBJECTIVE: To analyze the potential of the dual outer diameter screw and systematically evaluate the pull-out force of the dual outer diameter screw compared to the uncemented and cemented standard pedicle screws with special regard to the pedicle diameter and the vertebra level. METHODS: Sixty vertebrae of five human spines (T 6 -L 5 ) were sorted into three study groups for pairwise comparison of the uncemented dual outer diameter screw, the uncemented standard screw, and the cemented standard screw, and randomized with respect to bone mineral density (BMD) and vertebra level. The vertebrae were instrumented, insertion torque was determined, and pull-out testing was performed using a material testing machine. Failure load was evaluated in pairwise comparison within each study group. The screw-to-pedicle diameter ratio was determined and the uncemented dual outer diameter and standard screws were compared for different ratios as well as vertebra levels. RESULTS: Significantly increased pull-out forces were measured for the cemented standard screw compared to the uncemented standard screw (+689 N, P < 0.001) and the dual outer diameter screw (+403 N, P < 0.001). Comparing the dual outer diameter screw to the uncemented standard screw in the total study group, a distinct but not significant increase was measured (+149 N, P = 0.114). Further analysis of these two screws, however, revealed a significant increase of pull-out force for the dual outer diameter screw in the lumbar region (+247 N, P = 0.040), as well as for a screw-to-pedicle diameter ratio between 0.6 and 1 (+ 488 N, P = 0.028). CONCLUSIONS: For clinical application, cement augmentation remains the gold standard for increasing screw stability. According to our results, the use of a dual outer diameter screw is an interesting option to increase screw stability in the lumbar region without cement augmentation. For the thoracic region, however, the screw-to-pedicle diameter should be checked and attention should be paid to screw cut out, if the dual outer diameter screw is considered.
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Parafusos Pediculares , Fenômenos Biomecânicos/fisiologia , Cimentos Ósseos/farmacologia , Densidade Óssea/fisiologia , Cadáver , Remoção de Dispositivo , Humanos , Vértebras Lombares/cirurgia , Teste de Materiais , Polimetil Metacrilato/farmacologia , Desenho de Prótese , Falha de PróteseRESUMO
In total knee arthroplasty (TKA), patellofemoral groove design varies greatly and likely has a distinct influence on patellofemoral biomechanics. To analyse the selective influence, five patellofemoral design variations were developed based on Genesis II total knee endoprosthesis (original design, being completely flat, being laterally elevated, being medially elevated, and both sides elevated) and made from polyamide using rapid prototyping. Muscle-loaded knee flexion was simulated on 10 human knee specimens using a custom-made knee simulator, measuring the patellofemoral pressure distribution and tibiofemoral and patellofemoral kinematics. The measurements were carried out in the native knee as well as after TKA with the 5 design prototypes. The overall influence of the different designs on the patellofemoral kinematics was small, but we found detectable effects for mediolateral tilt (p < 0.05 for 35°-80° flexion) and translation of the patella (p < 0.045 for 20°-65° and 75°-90°), especially for the completely flat design. Considering patellofemoral pressures, major interindividual differences were seen between the designs, which, on average, largely cancelled each other out. These results suggest that the elevation of the lateral margin of the patellofemoral groove is essential for providing mediolateral guidance, but smooth contouring as with original Genesis II design seems to be sufficient. The pronounced interindividual differences identify a need for more patellofemoral design options in TKA.
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BACKGROUND: In this retrospective study, both the patients' and surgeons' satisfaction with resection of the first through fifth metatarsal heads for long-standing rheumatoid forefoot deformity was evaluated. METHODS: Thirty-four patients (56 feet) had first through fifth metatarsal head resection. After a mean time of 5.3 years, 39 feet (69.6%) (26 patients) were examined clinically and radiographically. RESULTS: The complication rate was 14% (8 of 56). There were four superficial and four deep wound infections. Plantar pressure pain under the resected metatarsal heads occurred in six feet. Most patients rated their cosmetic and functional results as good. Eighteen percent of patients (6 of 34) were satisfied and 78% (26 of 34) were satisfied with reservations. Thirty-three percent of patients (11 of 34) were pain free and 53% (18 of 34) had mild pain. The surgeons assessment of the patients' anatomical correction (cosmesis) was good in 90% (50 of 56) and poor in 10% (6 of 56). CONCLUSIONS: Our results, which are comparable to those of other studies, confirm the success of metatarsal head resection for the treatment of inflammatory forefoot destruction in rheumatoid arthritis to correct deformity, reduce pain, improve ambulation, and offer the patient a greater variety of shoewear.
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Artrite Reumatoide/cirurgia , Deformidades Adquiridas do Pé/cirurgia , Ossos do Metatarso/cirurgia , Idoso , Artrite Reumatoide/diagnóstico por imagem , Seguimentos , Deformidades Adquiridas do Pé/diagnóstico por imagem , Antepé Humano/cirurgia , Humanos , Tempo de Internação , Pessoa de Meia-Idade , Satisfação do Paciente , Cuidados Pós-Operatórios , Radiografia , Estudos Retrospectivos , Inquéritos e Questionários , Fatores de Tempo , Resultado do Tratamento , CaminhadaRESUMO
OBJECTIVE: Infection after total hip (THA) and knee arthroplasty (TKA) is a serious complication which typically leads to a long lasting and intensive surgical and medicamentous treatment. The aim of this study was to identify factors that influence outcome after revision surgery caused by prosthetic infection. METHODS: We retrospectively analyzed 64 patients who had revision surgery between 1989 and 2009 due to periprosthetic infection. We examined a total of 69 joints (TKA: 36%, THA: 64%), follow-up 5.1 years (0.5-21 years) after the initial surgical intervention. The mean patient age at time of surgery was 67 years old (43-79 years old). Clinical data and scores including the Western Ontario and McMaster Universities (WOMAC)-Index, the Harris Hip Score (HHS) and the Hospital for Special Surgery Score (HSS) were surveyed. RESULTS: There was no difference in clinical scores regarding treatment between a single and a multiple stage treatment regime. Infections with multiple microorganisms and Enterococcus spp. lead to a significantly higher number of interventions. Using a modified Tsukayama system we classified 24% as type I, 34% type II and 42% type III- infections, with no differences in clinical outcome. Overweight patients had a significantly lower HHS and WOMAC-score. Immunosuppression leads to a worse WOMAC and HSS-Score. An increased number of procedures was associated to a limping gait. CONCLUSION: Thorough surgical technique leads to good clinical results independent of infection-type and treatment philosophy. Level of Evidence III, Case Control Study.
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BACKGROUND: Anterior cruciate ligament rupture can lead to symptomatic instability, especially during pivoting activities, which are often associated with increased anterior and rotational tibial loading. Therefore, the purpose of our robot-aided in-vitro study was to analyze the influence of tibial rotation on anterior knee stability under three anterior cruciate ligament conditions. METHODS: Ten human knee specimens were examined using a robotic system. Anterior tibial translations were measured during anterior force application at internally and externally rotated positions of the tibia (5° steps until 4 Nm was reached) at 20°, 60°, and 90° of flexion. The native knee was compared with the knee with deficient and replaced anterior cruciate ligament. FINDINGS: Tibial rotation significantly influenced anterior tibial translation (P<0.001), with differences of up to 12 mm between the largest and smallest anterior translation in the deficient knee. The largest influence of the anterior cruciate ligament on anterior translation was found in slightly externally rotated positions of the tibia (5°-10° at 20° of flexion; 0°-5° at 90° of flexion). Significantly increased anterior tibial translation (up to 7 mm) was measured after anterior cruciate ligament resection, which could be almost completely restored by the replacement (remaining difference<1mm) over a wide range of tibial rotations. INTERPRETATION: Tibial rotation clearly influences anterior tibial translation. Because the greatest effect of the anterior cruciate ligament was found in slightly externally rotated positions of the tibia, increased attention to tibial rotation should be paid when performing the Lachman and anterior drawer tests.
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Reconstrução do Ligamento Cruzado Anterior/métodos , Ligamento Cruzado Anterior/cirurgia , Articulação do Joelho/fisiologia , Articulação do Joelho/cirurgia , Amplitude de Movimento Articular , Robótica , Tíbia/fisiologia , Tíbia/cirurgia , Idoso , Idoso de 80 Anos ou mais , Fenômenos Biomecânicos , Cadáver , Feminino , Humanos , Joelho/cirurgia , Pessoa de Meia-Idade , RotaçãoRESUMO
BACKGROUND AND OBJECTIVES: Despite the recommendations of national and international societies for the treatment of patients with acute neck and back pain, still too many radiologic examinations were performed. The purpose of this study was to analyze and optimize diagnostics and treatment of patients with acute back pain. METHODS: The medical records of 484 patients presented to the emergency clinic with acute neck or back pain were analyzed for clinical history, physical examination, radiographic findings and therapy. RESULTS: Radiographs of the lumbar, cervical, or thoracic spine were performed in 338 cases (70%). Radiographs were normal in 142 patients (42%) and degenerative changes were identified in 123 patients (36%). Only 2 patients (0.4%) had radiographic findings that had direct therapeutic relevance: 1 patient with metastatic disease and 1 patient with posttraumatic C1-C2 instability. For most patients without sensorimotor deficits and absent specific indications for radiography ("red flags"), therapy was not affected by the results of radiography. CONCLUSIONS: Plain radiography of the spine was unnecessary in most patients initially evaluated with non-specific acute back pain and does not improve the clinical outcome. The implementation of national and international guidelines is a slow process, but helps to reduce costs and to protect patients from unnecessary ionizing radiation exposure.
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Dor nas Costas/diagnóstico por imagem , Cervicalgia/diagnóstico por imagem , Coluna Vertebral/diagnóstico por imagem , Procedimentos Desnecessários , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Serviços Médicos de Emergência , Feminino , Humanos , Região Lombossacral/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Ortopedia , Radiografia , Adulto JovemRESUMO
Local adjuvant treatment of giant cell tumours (GCTs) of the bone with phenol has led to a significant reduction in recurrence rates. In the current study, the optimal phenol concentration and duration of intralesional exposure were evaluated. Specimens of GCTs were exposed to various concentrations of phenol solution (6, 60 and 80%) for either 1 or 3 min. Following embedding in glutaraldehyde, the tumour cell layers were examined by transmission electron microscopy. Destroyed cell organelles indicated the penetration depth as a sign of denaturation. Incubation of GCT specimens with 6% phenol solution for 3 min resulted in the most tissue damage and the deepest tissue penetration of â¼200 µm. Incubation with 60 and 80% phenol solution reached a penetration depth of only â¼100 µm. Phenol instillation may be used for the treatment of small scattered cellular debris following intralesional curettage; however, it is not suitable for treatment of remaining solid tumour tissue of GCT. The use of high phenol concentrations has no benefit and increases the risk of local or systemic intoxication.
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OBJECTIVE: The aim of this study was to analyze the setting for dislocations and redislocations after primary and revision total hip arthroplasty (THA), identify risk factors and optimize treatment. METHODS: This study included 56 patients with a dislocated hip following THA (n=5,205) between 1984 and 2005 and a matched control group (n=55). Hospital charts and radiographs of all patients in both groups were analyzed. Thirty-one patients in the study group were followed both clinically and radiologically. RESULTS: The dislocation rate after primary THA was 1.1% (56/5,205) and the redislocation rate after a first occurrence was as high as 39%. There was a positive correlation between the time intervals from the surgery to first dislocation and from the first dislocation to second dislocation (r=0.4). Most of the primary dislocations occurred within a short period of time after surgery, thus favoring consecutive dislocations. Female gender, as well as revision arthroplasty, was associated with a higher incidence of dislocations. No relation was found between the orientation of the acetabular cup and dislocation. CONCLUSION: To prevent redislocations after the first occurrence, we suggest thorough evaluation of possible technical faults which should be addressed surgically. Considering the high redislocation rate, we also advocate a stringent conservative treatment regime especially after the first THA dislocation.
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Artroplastia de Quadril/efeitos adversos , Luxação do Quadril/etiologia , Adulto , Feminino , Luxação do Quadril/epidemiologia , Luxação do Quadril/terapia , Humanos , Masculino , Análise por Pareamento , Complicações Pós-Operatórias/epidemiologia , Recidiva , Reoperação , Fatores de RiscoRESUMO
Although mid- to long-term results after total ankle replacement have improved because of available second- and third-generation devices, failure of total ankle replacement is still more common compared with total hip replacement and total knee replacement. The portfolio of available total ankle replacement revision component options is small. Furthermore, the bone stock of the tibiotalar region is scarce making it difficult and in some situations impossible to perform revision total ankle replacement. In these cases tibiotalar and tibiotalocalcaneal fusions are valuable options. This article describes which surgical procedures should be performed depending on the initial situation and gives detailed advice on surgical technique, postoperative care, and clinical results.
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Articulação do Tornozelo/cirurgia , Artrodese , Artroplastia de Substituição , Articulação do Tornozelo/fisiopatologia , Contratura/cirurgia , Humanos , Cuidados Pós-Operatórios , Complicações Pós-Operatórias/cirurgia , Falha de Prótese , Reoperação , Articulação Talocalcânea/cirurgia , Tálus/patologia , Suporte de CargaRESUMO
Custom femoral components have been developed for total hip arthroplasty to maximize cortical form-fit and thereby to reduce the problems of stress shielding and aseptic loosening. Limited information is available about how much endosteal cortical contact can actually be achieved with these expensive implants. The aim of this study was therefore to verify the exact cortical contact of a custom made stem using microsections and comparing it to a standard stem with similar design. In 8 human femurs (3 matched pairs and 2 separate specimens), custom femoral prostheses (Adaptiva; 5 femurs: 3 matched and 2 separate) and conventional femoral prostheses (Alloclassic; 3 matched femurs) were implanted. Endosteal cortical contact was determined from CAD planning drafts and microsections cut from the specimens with a diamond saw. Microsection analysis of the paired femurs showed that contact between prosthesis and bone varied clearly along the length of the femoral stem. Total cortical contact was considerably greater in custom prostheses than conventional prostheses (custom, 47%; conventional, 32%), but markedly less than the total contact predicted by the manufacturer (84% to 90%). The custom prosthesis had more lateral cortical contact on CAD planning drafts (cortical contact: medial, 60%; lateral, 53%) than on specimen microsections after implantation (medial, 64%; lateral, 24%).In summary, the philosophy of anchorage of both prostheses types could be confirmed. However, areas of cortical contact of the custom made prosthesis were considerably smaller compared to the pre-operative planning.
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Considerable immediate periprosthetic bone density changes after implantation of femoral stems have been observed comparing DEXA measurements taken pre- and post-operatively. This is important in relation to the interpretation of DEXA studies. We analysed these density changes under standardised experimental conditions. Five human femora were implanted with a custom made femoral stem and ten femora with a standard cementless prosthesis. Densitometry was performed at various stages of implantation. Following rasping only slight density changes were noted (-2.7% to +0.7%). Comparing post-implantation and pre-operative measurements, all custom made stems with a proximal press-fit demonstrated clear increases in proximal periprosthetic bone density of +11% and +14%. In contrast, the standard prosthesis with a distal press-fit showed a loss of -5% and -2% in the proximal zones. Measurements following removal of the implants demonstrated hardly any density changes (0% to -4%) compared to the pre-operative measurements. We concluded that compacting of trabecular bone or bone loss due to rasping are not the main causes of density changes. Substantial measuring errors exist. For examination of periprosthetic bone density changes, pre-operative initial measurements should not be used as a baseline for comparison. Studies should commence with an immediate postoperative measurement.
Assuntos
Artroplastia de Quadril/instrumentação , Densidade Óssea/fisiologia , Reabsorção Óssea/etiologia , Fêmur/metabolismo , Prótese de Quadril/efeitos adversos , Complicações Pós-Operatórias , Absorciometria de Fóton , Artroplastia de Quadril/efeitos adversos , Reabsorção Óssea/metabolismo , Remoção de Dispositivo , Fêmur/diagnóstico por imagem , HumanosRESUMO
ABSTRACT Objective: Infection after total hip (THA) and knee arthroplasty (TKA) is a serious complication which typically leads to a long lasting and intensive surgical and medicamentous treatment. The aim of this study was to identify factors that influence outcome after revision surgery caused by prosthetic infection. Methods: We retrospectively analyzed 64 patients who had revision surgery between 1989 and 2009 due to periprosthetic infection. We examined a total of 69 joints (TKA: 36%, THA: 64%), follow-up 5.1 years (0.5-21 years) after the initial surgical intervention. The mean patient age at time of surgery was 67 years old (43-79 years old). Clinical data and scores including the Western Ontario and McMaster Universities (WOMAC)-Index, the Harris Hip Score (HHS) and the Hospital for Special Surgery Score (HSS) were surveyed. Results: There was no difference in clinical scores regarding treatment between a single and a multiple stage treatment regime. Infections with multiple microorganisms and Enterococcus spp. lead to a significantly higher number of interventions. Using a modified Tsukayama system we classified 24% as type I, 34% type II and 42% type III- infections, with no differences in clinical outcome. Overweight patients had a significantly lower HHS and WOMAC-score. Immunosuppression leads to a worse WOMAC and HSS-Score. An increased number of procedures was associated to a limping gait. Conclusion: Thorough surgical technique leads to good clinical results independent of infection-type and treatment philosophy. Level of Evidence III, Case Control Study.