Efecto del ejercicio físico sobre las prótesis articulares / Effect of physical exercise on articular prostheses

El individuo adulto que tiene una artrosis grave de rodilla o cadera presenta dolor e incapacidad para la actividad física, lo que puede interferir con las actividades de la vida diaria. En ocasiones el tratamiento conservador no es suficiente para mejorar esta patología, por lo que la cirugía puede proporcionar mejoras sustanciales en estos pacientes. La sustitución protésica de rodilla y cadera son los procedimientos quirúrgicos que se practican de forma más habitual en los hospitales de Cirugía Ortopédica y Traumatología en España. Representan una clara mejoría en la sintomatología y calidad de vida de estos pacientes. En general el éxito del resultado depende de la selección del paciente y de sus expectativas, de la técnica, del diseño de los componentes, de la rehabilitación y de la prevención de las complicaciones. Los resultados de las artroplastias de sustitución se han estudiado utilizando parámetros o escalas que analizan el dolor, la función, los hallazgos radiológicos, la calidad de vida e incluso su coste-efectividad. Muy poco se ha analizado sobre el ejercicio y la actividad física tras una artroplastia de sustitución. El objetivo de este trabajo es realizar una revisión de las recomendaciones de ejercicio físico tras una prótesis total de cadera o rodilla y cuáles son esos conocimientos científicos y biomecánicos que justifican dichas recomendaciones (AU)

Rodillas protésicas. Clasificación e indicaciones clínicas / Prosthitic knees. Clasification and clinical prescription

La rodilla protésica es uno de los elementos claves en el diseño de las prótesis modulares y la aparición de nuevos mecanismos junto con la proliferación de rodillas ha complicado su clasificación y prescripción. En este trabajo revisamos los distintos mecanismos de rodillas, los agrupamos según su mecanismo de acción y proponemos al lector una guía orientativa para su prescripción. Para ello hemos realizado una revisión bibliográfica en la base de datos médica Medline y hemos recabado información de la industria ortoprotésica. Para aquellos puntos en que no existen criterios firmes exponemos el criterio que seguimos según nuestra experiencia (AU)

Managing bone loss with augmentation.

Augmentation blocks are effective ways of treating the problem of bone loss on the distal and posterior femur. They allow accurate and durable reestablishment of the distal and posterior joint line in revision total knee replacements. They are particularly appropriate in revisions being carried out in elderly, osteopenic patients with severe deformities or instabilities. Revision instrumentation can and should philosophically and mechanically remind one of and be consistent with primary total knee instrumentation.

Sins of omission: what the brochures don't tell you.

I have had an opportunity to share with you a few items about surgical technique and instrumentation that are not in most brochures. There are two other instruments that we have not discussed yet that are probably the most important ones to bring into your operating room: your eyes and your brain. Use them wisely and you will have success.

Complications after concomitant bilateral total knee arthroplasty in elderly patients.

OBJECTIVE: To determine the risks associated with performance of bilateral total knee arthroplasty (TKA) in elderly patients. MATERIAL AND METHODS: Ninety-eight patients with osteoarthritis who were 80 years of age or older and underwent concomitant cemented bilateral TKA were matched (on the basis of gender, surgeon, year of surgical treatment, age, and diagnosis) with 98 patients who underwent cemented unilateral TKA to compare the number and types of complications in these two groups. The groups did not differ in the number and type or severity of premorbid medical conditions, anesthetic risk, and type of anesthesia. RESULTS: One hundred nineteen postoperative complications occurred in 63 patients in the bilateral TKA group; in contrast, 72 complications occurred in 49 patients in the unilateral TKA group. The difference between the two groups in the total number of complications was significant. Specifically, significant differences between the two groups were noted in the occurrence of cardiovascular and neurologic complications. On paired analysis, congestive heart failure and acute delirium were found to be significantly more frequent in the bilateral TKA group than in the unilateral TKA group. We noted a trend toward an increased mortality rate in the bilateral group (four patients) versus the unilateral group (no deaths). CONCLUSION: Patients 80 years of age or older who undergo concomitant bilateral TKA are at increased risk for cardiovascular and neurologic complications during the postoperative period in comparison with matched patients who undergo unilateral TKA.

Safety and efficacy of bilateral total knee arthroplasty.

Recent studies have reported increased morbidity associated with bilateral simultaneous total knee arthroplasty (TKA). The purpose of this study was to evaluate the morbidity and clinical outcome associated with simultaneous bilateral TKA in contrast to unilateral TKA. All primary TKAs, either unilateral or simultaneous bilateral, performed between May 1988 and July 1993 were retrospectively reviewed. Patients were evaluated using Knee Society scores both before surgery and a minimum of 6 months after surgery. In addition to routine demographics, patients were evaluated for the incidence of both local wound and systemic complications. It is concluded that performing simultaneous bilateral TKA does not result in any significant increase in patient morbidity or compromise in postoperative function when compared with unilateral TKA.

Rollback in posterior cruciate ligament-retaining total knee arthroplasty. A radiographic analysis.

A clinical and radiographic study of 49 posterior cruciate ligament-retaining total knee arthroplasties in 38 patients (11 bilateral, 27 unilateral), using prostheses of the same design, was undertaken to quantify the amount of in vivo rollback (ie, the anteroposterior translation of the tibia with respect to the femur during flexion). The mean difference in the distances between the contact points of the knees in full extension and in 90 degrees flexion (ie, the rollback distance) was a posterior translation of the contact point of -0.2 mm (-12.7 to +7l6 mm; SD, 4.7 mm) relative to the prosthetic tibial tray, corresponding to an average translation of 0% of the prosthetic tibial tray depth, and -0.2 mm (-12.5 to +9.1 mm; SD, 4.8 mm) relative to the tibia itself, corresponding to an average translation of 0% of the true tibial surface depth. The differences between the rollback values obtained from the 90 degrees and full-extension radiographs relative to the prosthetic tibial tray (P = .63) and the true tibia (P = .89) were not statistically significant. Intraobserver (P = .27-.50) and interobserver (P = .13-.72) reliability tests showed that the differences between radiographic measurements taken by the same observer at two different points in time and by two different observers were not statistically significant. No correlations were found between the degree of translation of the tibiofemoral contact point relative to the prosthetic tibial tray and the posterior tilt of the tibial tray (R2 = .12), the preoperative tibiofemoral angle (R2 = .34), and the postoperative tibiofemoral angle (R2 = .027). No correlations were found between the degree of translation of the tibiofemoral contact point relative to the true tibia and the posterior tilt of the tibial tray (R2 = .16), the preoperative tibiofemoral angle (R2 = .14), and the postoperative tibiofemoral angle (R2 = .034). In conclusion, this study indicated no demonstrable rollback occurring in the posterior cruciate ligament-retaining total knee arthroplasty used in this study.

Artroplastia unicompartimental do joelho: experiência após 22 casos / Unicompartmental knee arthroplasty: experience after 22 cases

Os autores apresentam 22 casos de artroplastia unicompartimental do joelho operados pelo grupo de joelho do INTO-HTO-RJ, no período compreendido entre fevereiro/90 e agosto/96, com seguimento médio de 56,70 meses; dois casos foram excluídos: um por näo acompanhar o protocolo de revisöes e o outro por ter-se extraviado o prontuário. Do total de pacientes operados, cinco casos evoluíram com resultado insatisfatório, necessitando conversäo para artroplastia total do joelho, sendo dois casos de osteonecrose e três de osteoartrose. Os resultados nos demais pacientes da série foram considerados como excelentes do ponto de vista clínico e radiológico. Concluem os autores que os resultados säo animadores, devendo ser considerada como boa opçÒo terapêutica no tratamento da patologia degenerativa monocompartimental do joelho.

Comparison of the results of bilateral total knee arthroplasty with and without patellar replacement for rheumatoid arthritis. A follow-up note.

Simultaneous bilateral total knee arthroplasty was performed in twenty-six patients who had rheumatoid arthritis, and a patellar replacement was performed concurrently in one randomly selected knee in each patient. A lateral retinacular release was performed in all knees. The patients were followed for at least six years (mean, 6.6 years; range, 6.0 to 7.5 years), and the postoperative status of the patients was evaluated with the knee score of The Hospital for Special Surgery. Pain on standing and on ascending or descending stairs as well as tenderness of the patellofemoral joint also were assessed. The over-all score and the individual scores for pain, function, range of motion, muscle strength, flexion contracture, and instability were not significantly different between the knees that had had a patellar replacement and those that had not. However, pain on standing and on ascending or descending stairs as well as tenderness of the patellofemoral joint were only noted in knees that had not had a patellar replacement. These findings suggest that, in order to diminish pain on standing and on using stairs, replacement of the patella during total knee arthroplasty is preferable for patients who have rheumatoid arthritis.

Restoration of limb alignment in total knee arthroplasty: evaluation and methods.

Obtaining adequate alignment is critical in the proper performance of total knee arthroplasty (TKA). This study prospectively evaluates 350 patients who had previous TKA. Its goals are to establish the best method of measuring limb alignment as well as the best method of restoring ideal alignment. Intramedullary alignment techniques were compared with extramedullary, and alignment of each limb was evaluated by both long (scanogram) and short films (14 inches x 17 inches). Conclusions reached were (1) that only data obtained from full limb radiographs are accurate for determining and reporting limb alignment in TKA, (2) that alignment values should be reported relative to the mechanical axis of the limb because of the variability of the femoral anatomic angle, (3) that intramedullary femoral guides are required to make accurate femoral bone cuts, (4) that extramedullary tibial guides permit accurate cuts of the proximal end of the tibia, and (5) that tibial intramedullary guides are not only unnecessary but also potentially misleading.

Intramedullary goniometer can improve alignment in knee arthroplasty surgery.

Fifty total knee arthroplasties were performed using an intraoperative intramedullary goniometer to measure the angle of the distal femoral cut. When deviations of 1 degree or more were found, angled cutting blocks ranging from 1 degree to 5 degrees were used to recut the distal femur. Revised femoral cuts were made it 25 knees (50%). Postoperative evaluation from weight-bearing long-standing anteroposterior radiographs revealed an average distal femoral angle deviation from preoperative planning of 0.64 degree (range, 0 degree-3 degrees). This was statistically significantly different from the value for a comparison group of 50 knees on which arthroplasties were performed without the intraoperative goniometer with an average femoral angle deviation of 1.44 degrees (range, 0 degree-4 degrees) (P < .05). In the control group, there were 7 knees (14%) that deviated by 3 degrees or more versus only 2 knees in the study group. The authors conclude that an intramedullary goniometer is fast, is simple to use, and leads to more accurate preparation of the distal femur in total knee arthroplasty.

A midvastus muscle-splitting approach for total knee arthroplasty.

This study presents a modification of the medial parapatellar surgical approach for total knee arthroplasty. This approach separates the vastus medialis muscle in the direction of its fibers beginning at the superior pole of the patella. One hundred eighteen consecutive total knee arthroplasty cases, performed by a single surgeon, were randomized prospectively to receive a medial parapatellar or midvastus muscle-splitting surgical approach. The frequency of lateral retinacular releases was recorded, patellar tilt and translation were measured, and quadriceps strength was tested. The midvastus muscle-splitting approach provided excellent exposure to all knees. Patellar stability and quadriceps strength were equivalent for the two approaches. It is concluded that the midvastus muscle-splitting approach is an efficacious alternative to the medial parapatellar approach for primary total knee arthroplasties.

[Robot-assisted knee endoprosthesis]. / Roboterunterstützung in der Knieendoprothetik.

With the development of powerful computer systems, computer-assisted medical diagnosis and therapy have become common over the last 10 years. Even in the surgical field, computer- and robotic-assisted techniques are becoming practical but are not yet used on a daily basis. In the orthopaedic field, computer and robotic assistance is used in planning and performing demanding three-dimensional osteotomies, setting pedicle screws in the spine and milling the femoral medullary canal in total hip replacement. This article introduces a computer- and robotic-assisted system for performing arthroplasty in total knee replacement procedures.

Soft-tissue balancing with pressure distribution during total knee arthroplasty.

We measured the pressure distribution across the tibiofemoral and patellofemoral joints during total knee arthroplasty (TKA) using Fuji pressure-sensitive film (Prescale) in 51 patients (63 joints) comparing the results with those in 21 patients in whom Prescale was not used. We classified the stress-distribution patterns in the tibiofemoral joints into four types: normal, varus-valgus instability, rotational malalignment, and a combination of instability and malrotation. The medial ligaments were then released according to the information obtained from these patterns. The conformity ratio of the contact area between repeated trials was 87.0%. Pressure distribution across the patellofemoral joints was also considered. There was a significant decrease in the mean valgus stress angle in the Prescale group compared with the control group (p < 0.01). Release of the lateral retinaculum according to the results showed no significant differences in subluxation of the patella between the released group and the group which did not appear to need this procedure.

Total knee arthroplasty for osteoarthritis in hereditary onycho-osteodysplasia (nail-patella syndrome): a case report.

Onycho-osteodysplasia is an unusual disorder that affects bone, fingernails, and the kidneys. The knees may be involved with a hypoplastic, dislocated patella, and premature osteoarthritis with deformity may develop. The following is a case report of a patient with this disorder in which a total knee arthroplasty was performed.

Heterotopic ossification after total knee arthroplasty.

Heterotopic ossification (HO) is a rare complication following total knee arthroplasty (TKA). In the case report presented, a 52-year-old man who had previously undergone TKA for osteoarthritis noticed painful limitation of range of motion (ROM) in spite of active participation in physical therapy and the use of a continuous passive motion machine. A plain radiograph 1 month after surgery revealed HO anterior to the distal femoral shaft in the quadriceps expansion. Ambulation for this patient was limited to short distances because of severe pain and limitation in ROM. The patient underwent manipulation under general anesthesia 2 months after the TKA. Range of motion in flexion improved from 50 degrees to 110 degrees, and the patient became ambulatory without assistive devices. However, the flexion range deteriorated to 50 degrees over a period of 4 months, and ambulation again became significantly limited. The patient underwent resection of HO 6 months after manipulation and regained his ROM to 110 degrees in flexion. He was prescribed indomethacin after surgery for 2 months to prevent recurrence of HO. Follow-up radiographs 3 months after surgery revealed minimal recurrence of HO. The patient's ROM did not deteriorate, and he remained ambulatory. Heterotopic ossification should be suspected in post-TKA patients if ROM does not improve. Physical therapy including ROM exercises remains an essential component in the treatment of HO. Manipulation under general anesthesia or surgical resection of HO may be inevitable in certain patients whose ambulation is significantly limited.