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PubMed2003

Above-the-knee amputation after a total knee replacement: prevalence, etiology, and functional outcome.

BACKGROUND: Despite modern surgical techniques, salvage of a failed total knee replacement remains a challenge. In certain situations, when other treatment options have been exhausted, patients with a failed total knee replacement may become candidates for above-the-knee amputation. The objective of this study was to assess the prevalence, etiology, and functional outcome of above-the-knee amputation performed proximal to an ipsilateral total knee replacement. METHODS: From 1970 to 2000, 18,443 primary total knee replacements were performed at our institution; sixty-seven (0.36%) were eventually followed by above-the-knee amputation. Forty-two of the amputations were performed for a cause unrelated to the total knee replacement, most commonly peripheral vascular disease (twenty-four knees). The remaining twenty-five above-the-knee amputations were performed for causes related to the total knee replacement: nineteen were done for uncontrollable infection; two, for periprosthetic fracture; two, for pain; one, for severe bone loss; and one, for a vascular complication. RESULTS: The twenty-five above-the-knee amputations performed for causes related to the total knee replacement were done at an average of 8.6 years (range, eight days to 23.6 years) after the replacement. The prevalence of above-the-knee amputations done for causes related to total knee replacement was 0.14%. Complications after the above-the-knee amputation included deep infection in five patients and superficial infection and skin necrosis in one each; there was also one perioperative death. Nine of the twenty-five limbs were fitted with an above-the-knee prosthesis, but only five patients were walking even to a limited degree with the prosthesis at the time of the last follow-up. CONCLUSIONS: The overall prevalence of amputation after total knee arthroplasty at our tertiary care center was 0.36%. The majority (63%) of the amputations were performed for reasons not attributable to complications of the arthroplasty. The functional outcome after amputation performed above a total knee replacement is poor. A substantial percentage of the patients were never fitted with a prosthesis, and those who were seldom obtained functional independence.

Aged↗
PubMed1995

Enumeration of human knee prostheses--an overview.

Very often clinicians prescribe a limited number or only one type of knee mechanism because it has been found reliable or perhaps specific information on the range and variety of all available mechanisms has not been on hand. The clinician rarely has the opportunity to see all the mechanisms in a common perspective to compare the relative merits of one mechanisms with another. An attempt has been made to enumerate the available human knee-prostheses, both implants and external prostheses, according to their motion. An historical development of knee prosthesis is discussed. A classification procedure is developed for both internal and external prostheses based on their primary functions. The two major classifications in either of these prostheses are monocentric and polycentric mechanisms. A mechanism whose center of rotation does not change through out the range of motion is considered as monocentric mechanism and a mechanism whose center of rotation changes during its operation is considered as polycentric mechanism. The implants are categorized as hinged and non-hinged knee joints. The external prostheses are further classified based on certain primary functions like control in swing phase and/or in stance phase and in extension. The hierarchical classification scheme will benefit kinematicians and designers to analyze the available mechanisms and make necessary improvements. This will also provide a ready-reference to the prosthetists in selecting the best-fit prosthesis from a large family of prostheses.

Artificial Limbs↗
PubMed1999

Periprosthetic bone remodelling after total knee arthroplasty: early assessment by dual energy X-ray absorptiometry.

The present investigation aims to evaluate periprosthetic bone remodelling after total knee arthroplasty by the use of dual-energy X-ray absorptiometry (DXA). Twelve patients affected by osteoarthrosis of the knee joint underwent primary total knee arthroplasty at an average age of 70.5 years. None of them had received a knee prosthesis before on the contralateral side. Anteroposterior and lateral DXA measurements of the femur, tibia and total knee (both sides) were taken 2 weeks, 3 and 9 months postoperatively. The 2-week measurement was used as an individual reference value to be compared with the 3- and 9-month findings. In addition, the contralateral knee was investigated also in order to estimate how far bone mineral loss was due to implantation or to an individual decline in bone mineral density (BMD). The comparison of BMD values after knee arthroplasty revealed a conspicuous decrease of bone density within 9 months. Bone mineral loss amounted to an average of 9.2% in anteroposterior and 17.8% in lateral DXA measurements. Lateral femur shots showed an average decrease of density of even 21.5%. In contrast, the BMD values of the contralateral knees remained almost unchanged. DXA, especially lateral shots of the femur, promises to be a suitable method for early assessment of periprosthetic bone remodelling after total knee arthroplasty.

Absorptiometry, Photon↗
PubMed1998

[Treatment of knee osteoarthritis].

Osteoarthritis of the knee is not a well defined illness, but is a result of different causes that may lead to joint failure due to chondral damage, synovial inflammation, subchondral bone formation, and the formation of osteophytes along the joint lines. The pathogenesis is unclear. We still lack treatment to cure the early process of chondral degeneration. The treatment of choice in early and moderate osteoarthritis of the knee is limited to counselling, physiotherapy, analgesics, and surgical correction of malalignment. Documentation is still lacking on chondral debridement and transplantation of the degenerated cartilage by cultured chondrocytes, periosteum or perichondrium. An effective and well documented treatment of end-stage osteoarthritis of the knee in the older population is replacement of the joint by a knee prosthesis.

Analgesics↗
PubMedDate not supplied

Knee rotation-plasty for malignant musculoskeletal tumors occurring around the knee joint.

BACKGROUND: In addition to the wide excision of malignant musculoskeletal tumor around the knee joint, surgical methods, such as total knee arthroplasty and knee rotation-plasty are available. Therefore, this study was undertaken to clarify the usefulness of knee rotation-plasty. MATERIALS AND METHODS: At the Chiba Cancer Center, knee rotation-plasty was performed in 27 patients with malignant musculoskeletal tumor around the knee joint. Patients were divided into two groups: Group S, in which operations were performed as salvage surgery (8 patients), and Group I, in which operations were performed as initial surgery (19 patients). The lower limb function was investigated in 17 patients (7 patients in Group S and 10 patients in Group I). The lower limb function was assessed by the Knee Evaluation System of International Symposium on Limb Salvage and the Knahr's assessment. RESULTS: Lower limb function in Group S measured an average of 25.7 points (85.6%), while the lower limb function in Group I measured an average of 23.6 points (78.7%). The majority of patients in both groups were capable of walking without a cane or doing light exercise with below-the-knee prosthesis, revealing good lower limb function. CONCLUSION: Whether it is performed as salvage or initial surgery, knee rotation-plasty can be useful method for reconstruction of the knee after wide excision of malignant musculoskeletal tumor around the knee joint.

Adolescent↗
PubMed1985

A study on the value of the modified KBM prosthesis compared with other types of prosthesis.

A study is reported on the value of a modified KBM prosthesis compared with other types of prostheses. Recently a new type of below-knee prosthesis (the so called modified KBM prosthesis) was introduced in the Netherlands. This prosthesis is now frequently used as a substitute for more conventional types. A study was carried out on the value of this new prosthesis, compared with the more conventional types, by means of a questionnaire sent to a group of patients who formerly used a more conventional type of prosthesis.

Adolescent↗
PubMed1994

Improved fit by asymmetric tibial prosthesis for total knee arthroplasty.

The adequacy of the fit of the prosthesis to the tibia is an important variable in the outcome of total knee arthroplasty. A good fit covers the cancellous bone of both condyles, involves the denser bone of the tibial shell, but does not overhang beyond the bone at any point. In this research, an anatomically shaped tibial prosthetic base plate was developed from tibial measurements. A series of five template sizes, chosen to fit our patient database, was then evaluated for fit in the operating room by one surgeon. The assessment included bone exposure and the overhang of the prosthesis beyond the bone perimeter. The measurements of overhang or bone exposure were analysed. A commercial prosthesis was used as a control. An asymmetrical tibial plate conformed well to the anatomical shape of the resected upper tibia resulting in very little exposed bone and very few cases of overhang. The absence of such overhang provides better function in the surrounding stabilizing soft tissues, and so permits recovery of the maximum range of motion post-operatively.

Anthropometry↗
PubMed2000

Muscle performance about the knee joint in patients who had distal femoral replacement after resection of a bone tumor. An objective study with use of gait analysis.

BACKGROUND: The treatment of a malignant bone tumor in the distal aspect of the femur often requires great sacrifice of bone and muscle. The extent of quadriceps removal has been reported to influence the long-term functional efficiency of a patient's gait. The objective of the present study was to determine gait function as it relates to the residual quadriceps strength and to the specific component or components of the quadriceps removed in patients treated with total knee replacement because of a malignant bone tumor in the distal aspect of the femur. METHODS: Sixteen patients were evaluated after implantation of a modular hinged cementless knee prosthesis. The patients were assigned to two groups on the basis of the different components of the quadriceps muscle that were resected. Group 1 consisted of five patients who had removal of the vastus medialis and the vastus intermedius and two who had removal of the vastus medialis only. Group 2 consisted of nine patients who had removal of the vastus lateralis and the vastus intermedius. Residual muscular strength about the treated knee was measured by voluntary maximum contraction isometric testing. Foot-ground reaction forces, kinematic and kinetic findings, and electromyographic activity during free-speed walking were recorded. RESULTS: The kinematic study showed that the patients in Group 1 tended to have a stiff-knee gait during stance, whereas those in Group 2 (in which the vastus medialis was spared) had a more regular flexion-extension knee pattern. Electromyographic findings showed that a higher percentage of patients in Group 1 had reduced or absent rectus femoris activity during the loading response. Compared with the contralateral side, knee-extension strength in the treated limb was decreased in both groups. However, there were no significant differences between the groups with respect to the pattern of strength loss. CONCLUSIONS: Good gait function can be achieved in patients with a distal femoral tumor that is treated with distal femoral resection, partial excision of the quadriceps, and total knee arthroplasty with insertion of a hinged prosthesis. Patients in whom the vastus lateralis and vastus intermedius were removed had better gait performance and a more physiological knee-loading pattern than did patients in whom the vastus medialis was removed.

Adult↗
PubMed1985

A new directly moulded patellar-tendon-bearing socket.

Silicone rubbers and casting tapes individually have previously been used in the manufacture of sockets (Swanson, 1972; Sweitzer, 1973; Ruder, 1977; Graves, 1980; Aqualite, 1982). The authors believe that the present combination of these materials to manufacture a directly moulded socket with a complete silicone rubber lining of variable thickness has not previously been described. The new socket, after addition of the modular components, allows fitting of an aligned below-knee prosthesis within three hours. The socket (Fig. 1.) is made directly on the below-knee stump, can be completed with experience in an hour and does not require the use of specialized equipment. The socket consists of an outer supportive Scotchflex layer inside which is a lining of soft smooth biocompatible silicone rubber of deliberately variable thickness to allow pressure tolerant areas to accept more load and pressure sensitive areas to accept less load (Fig.2). The thicker areas of silicone are produced by applying carefully cut Plastazote pads to the pressure sensitive areas. The thickness and extent of the pads is individually assessed according to the estimated sensitivity of the particular area (Fig. 3). The Scotchflex socket is then manufactured directly on the below-knee stump with these pads applied. The pads are then removed prior to insertion of a semi-liquid silicone rubber. Thus, when the socket with the liquid silicone rubber is re-applied to the stump, the space produced by the pads is filled by the rubber which then sets at room temperature. In this way a layer of variable thickness is produced.(ABSTRACT TRUNCATED AT 250 WORDS)

Artificial Limbs↗
PubMed2000

Tibial component fixation in porous- and hydroxyapatite-coated total knee arthroplasty: a radiostereo metric evaluation of migration and inducible displacement after 5 years.

A total of 51 knees (45 patients) with osteoarthrosis were stratified in a randomized study to receive a hydroxyapatite-coated Freeman-Samuelson (FS HA) or a porous-coated Miller-Galante II (MG II) uncemented total knee arthroplasty. Repeated clinical, radiographic, and radiostereometric analysis (RSA) evaluations of the tibial components were done for 5 years. The clinical outcome was equal at the 5-year follow-up (mean Hospital for Special Surgery score, 93). Standard radiographs displayed more zones around the tibial stem in the MG II group. RSA revealed that the FS HA components migrated less (smaller maximum total point motion and maximum subsidence) after 5 years and showed less inducible displacements at the 1-year follow-up. The stability of the implants obtained is equal to or better than cemented implants after 5 years. Key words: knee prosthesis, cementless, hydroxyapatite, radiostereometry, inducible displacement.

Aged↗
PubMed1984

Prostheses alignment: effect on gait of persons with below-knee amputations.

This study investigated the effect on gait of changing prosthetic alignment for five people with amputations. Three-dimensional angular kinematic data were recorded by electrogoniometers positioned at their hips and knees. Indices of symmetry were developed in time and frequency domains for motion data of lower limbs when walking. These measures of symmetry were determined at different prostheses alignment settings and used to assess the possibility of aligning below-knee prostheses on the basis of symmetry of lower limb motion. Optimal or neutral alignment of below-knee prosthesis, as selected by clinically experienced personnel, tended to minimize asymmetry of gait at the hips and knees for persons with below-knee amputations. The indices of symmetry showed that alignment changes to the prosthetic foot disrupt gait to a greater extent than do other alignment changes. Asymmetries of hip flexion-extension motions were more sensitive to alignment changes than were other asymmetries. An index was selected that showed sensitivity to changes in gait caused by changes in prosthetic alignment for below-knee amputations. Refinements and other applications of this index in rehabilitation are suggested.

Artificial Limbs↗
PubMed1981

[Surface arthroplasty of the knee by marmor prosthesis. Study of 35 unicompartimental prosthesis seen with a follow-up of 1 to 5 years (author's transl)].

The Marmor prosthesis may be used for a surface arthroplasty of the knee by means of a system of unicompartmental modules including 4 sizes of condylar ramps and 6 thicknesses of tibial plateaux in two widths. It is thus possible to treat one or both compartments and correct any axial deviation. The operative technique must be careful and accurate with regard to the positioning of the prostheses and the choice of thickness of the plateau to be inserted. Preoperative radiological assessment must be very precise, and include in particular films with monopodal weight bearing and in forced position in order to study the joint surfaces and predict the correction which must be applied. Fifty operations have been performed (in 37 cases for osteoarthrosis), but the essential aim of the present study is to report the results of 35 unicompartmental prostheses with a follow-up of 1 to 5 years (mean : 2 years and 2 months). Thirty results were assessed as good or very good. The most spectacular features were freedom from pain and the rapidity with which the results were obtained. They would seem to be clinically stable. Nevertheless, the development of 3 deteriorations of the tibial plateau after Marmor would appear to contraindicate the use of 6 mm thickness plateaux. In contrast to widespread opinion, the remaining compartment does not degenerate, so long as it was normal preoperatively and there has not been any hypercorrection of the deviation after unicompartimental arthroplasty. Nevertheless, the latter has its limits and whilst it may play a role in the treatment of certain cases of osteoarthrosis of the knee, it cannot replace either tibial osteotomy for correction of the axis or bicompartimental prostheses or total prostheses anchored in the diaphysis, which also have their indications.

Follow-Up Studies↗
PubMedDate not supplied

[Quantitative determination of spongiosa formation of tibial cortical bone following knee joint total prosthesis implantation].

Cancellization always occurs following implantation of total knee joint replacements. In the study reported here the extent of the cancellization process at the tibia corticalis was investigated; it was found that the extent of cancellization differs according to the height and the time factor. The danger of cancellization as a risk to the joint prosthesis is pointed out with reference to a case in which a fracture occurred. The problem of isoelastic joint prostheses as alternatives for avoiding cancellization is discussed.

Adult↗
PubMed1998

Pathologic supracondylar fracture due to osteolytic pseudotumor of knee following cementless total knee replacement.

Wear debris of polyethylene, polymethylmethacrylate, and metal have been recognized to be associated with foreign body reactions, osteolysis, and aseptic prosthetic loosening after joint replacement arthroplasty. Further, foreign body reaction due to the presence of extensive wear debris can cause aggressive granulomatous lesions and pathologic fracture. To our knowledge, there has been no previous report of pathologic fracture of the femur due to an agressive pseudotumor. This report describes a case of pathologic supracondylar fracture of the femur 6 years and 5 months after cementless total knee replacement arthroplasty. The fracture occurred through an aggressive expanding soft tissue mass that was a tumorlike lesion secondary to polyethylene wear debris. The lesion was associated with massive osteolysis around the femoral component of the total knee prosthesis.

Arthroplasty, Replacement, Knee↗
PubMed2000

Slide and flex, tighten, extend (SAFTE): a safe, convenient, effective, and no-cost approach to rehabilitation after total knee arthroplasty.

Many of the clinical aspects of total knee arthroplasty (TKA) are now standardized; however, treatment protocols for rehabilitation vary according to surgeon and physical therapy departments. The purpose of this article was to determine if the slide and flex, tighten, extend (SAFTE) approach after TKA is a satisfactory method of achieving functional range of motion (full extension and at least 90 degrees of flexion). Of patients in the study group, 70% achieved functional range of motion by the 7-week evaluation period. SAFTE is a safe, effective, and no-cost approach to achieve functional range of motion in TKA using a single-radius, posterior-stabilized knee prosthesis.

Aged↗