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Biomedical subjects

C H Rorabeck

Publications and source records attributed to C H Rorabeck.

At least 19 recordsLinked to original sources
PubMed2001

Patellar infera after high tibial osteotomy.

Forty-six knees in 41 patients that had undergone high tibial osteotomy (HTO) were evaluated to assess the potential correlation between alteration in the inclination of the proximal tibial articular surface and subsequent patellar height. Of the knees examined, 61% lost > or =5 degrees of posterior tibial inclination after HTO, whereas 54% of knees showed a relative lowering of patellar height of >10%, as measured by the Insall-Salvati ratio. The loss of the normal posterior tibial inclination was found to have a statistically significant association with the subsequent loss of the patellar height. Clinically, these results suggest that careful preservation of the posterior tibial inclination at the time of HTO could minimize the risk of subsequent patellar infera and alteration in patellofemoral mechanics.

Adult↗
PubMed2000

Prospective randomized clinical trial of continuous passive motion after total knee arthroplasty.

The authors report the results of a prospective randomized clinical trial using continuous passive motion after total knee arthroplasty. One hundred twenty patients were assigned randomly to one treatment group: No continuous passive motion (Group I), continuous passive motion from 0 degrees to 50 degrees and increased as tolerated (Group II), and continuous passive motion from 70 degrees to 110 degrees (Group III). The continuous passive motion was initiated in the recovery room and was maintained for a maximum of 24 hours at which point all patients began identical postoperative physiotherapy regimens. Patients were assessed preoperatively, during their hospital stay, at 6 weeks, 12 weeks, 26 weeks, and 52 weeks after their surgery. There were no statistical differences between any of the treatment groups regarding cumulative analgesic requirements, range of motion at any measured interval, length of stay (Group I, 5.1 days; Group II, 5.2 days; Group III, 5 days) or Knee Society scores. The current study does not support the use of short-term continuous passive motion after total knee replacement. A standard and a high flexion continuous passive motion protocol failed to show any advantage over physiotherapy alone in the parameters evaluated.

Analgesics↗
PubMed2000

Extensile exposures for revision hip arthroplasty.

Revision arthroplasty is being performed with increasing frequency and the cases are becoming increasingly complex. A key component to successful revision surgery is the surgical exposure. This is influenced by the surgeon's experience, the reason for revision, the type of components to be revised, the type of bone defects, and the previous exposures used. In simple revisions one of the standard hip approaches with which the surgeon is familiar often will suffice. However, with more complex cases an extensile or specialized approach may be necessary. No one approach is suitable for all cases and the surgeon must be familiar with several approaches, their relative indications, and possible complications.

Arthroplasty, Replacement, Hip↗
PubMed1999

Classification of periprosthetic fractures complicating total knee arthroplasty.

As the total number of knee arthroplasties increase, the frequency with which periprosthetic fractures will be encountered can be expected to increase as well. The classification of these fractures is an important aspect in the development of an understanding of these problems. Adequate classification systems allow accurate communication between researchers and comparisons to be made between different techniques. Classification systems also allow algorithms to be developed to guide clinicians in the diagnosis, investigation, and treatment of these fractures. The authors present an outline of the classification systems described for fractures occurring in relation to total knee arthroplasty.

Arthroplasty, Replacement, Hip↗
PubMed1999

Periprosthetic fractures of the femur complicating total knee arthroplasty.

Fractures of the femur in the presence of a total knee arthroplasty may occur intraoperatively or postoperatively. Management of these fractures is often challenging because of a variety of factors, including those related to the fracture itself, and the quality of the bone, prosthesis, and patient. Treatment options include nonoperative methods, reduction and internal fixation, and revision of the arthroplasty. Complications of treatment are not uncommon and may be severe. These issues are discussed in the article.

Algorithms↗
PubMed1999

Total knee replacement: should it be cemented or hybrid?

OBJECTIVE: To compare the complication rates associated with total knee arthroplasty against the types of fixation (hybrid or cemented), using a single total knee design (the anatomic modular knee [AMK] prosthesis). DESIGN: A prospective, nonrandomized, controlled trial. SETTING: University Hospital in London, Ont., a tertiary care teaching centre. PATIENTS: Two groups made up of 484 knees in 395 patients (89 bilateral). INTERVENTIONS: In 260 knees a hybrid configuration (cemented tibia and noncemented femur) was used (group 1). In 224 knees the femoral and tibial components were cemented (group 2). All patellae were cemented in both groups. MAIN OUTCOME MEASURES: Clinical results were assessed by The Knee Society Clinical Rating Scores at 3 months, 6 months and yearly intervals. Radiographic results were determined by 3-foot standing radiographs and at each follow-up visit standing knee radiographs, lateral and skyline views. Radiographs were analysed for alignment, presence or absence of radiolucent lines or changes in the position of the implant. All reoperations and nonoperative complications were recorded. RESULTS: At an average follow-up of 4.8 years, 8 knees (1.6%) required reoperation. An analysis of the complications leading to reoperation demonstrated no difference between the 2 groups. CONCLUSIONS: There was no difference in outcome whether the femoral component was cemented or not. Medium-term results of the AMK are excellent with a very low reoperation rate.

Aged↗
PubMed1999

The Install Award. Survivorship of the high tibial valgus osteotomy. A 10- to -22-year followup study.

The results of 106 high tibial valgus osteotomies in 85 patients were evaluated after a minimum 10-year followup to determine survivorship, complications, and risk factors associated with failure. Using Kaplan-Meier survivorship analysis, 73% of patients at 5 years, 51% of patients at 10 years, 39% at 15 years, and 30% at 20 years after high tibial osteotomy had not required conversion of the high tibial osteotomy to a total knee arthroplasty. Univariate Cox regression analysis of risk factors showed that age older than 50 years, previous arthroscopic debridement, presence of a lateral tibial thrust, preoperative knee flexion less than 120 degrees, insufficient valgus correction, and development of delayed union or nonunion were significantly associated with probability of early failure. Multivariate Cox regression analysis showed that a body mass index of less than 25 kg/m2, presence of a lateral tibial thrust, and development of delayed union or nonunion were significantly associated with probability of early failure. Using recursive partitioning analysis of risk factors with the Wilcoxon test, a subset of patients who were younger than 50 years of age and who had preoperative knee flexion greater than 120 degrees had a probability of survival after high tibial osteotomy approaching 95% at 5 years, 80% at 10 years, and 60% at 15 years. These results suggest that survival of high tibial osteotomy can be improved through careful patient selection and surgical technique.

Adolescent↗
PubMed1999

Popliteal vessels in knee surgery. A magnetic resonance imaging study.

Popliteal artery injury during surgery of the knee is rare but can have devastating consequences. The position of knee flexion has been thought to be protective for the popliteal artery, allowing it to fall back from the knee joint. No prior study has provided in vivo cross sectional evidence of the behavior of the popliteal vessels during knee flexion with the effect of gravity. Magnetic resonance imaging was used in nine volunteers to measure the distance of the popliteal artery and veins from the posterior proximal tibia at two levels corresponding to the levels of osteotomy in total knee arthroplasty and in high tibial osteotomy. Scans were taken with the knee in full extension and at 90 degrees flexion with the patient in the supine position, allowing for the effect of gravity. Considerable variation in behavior of the vein and the artery was observed at the high tibial osteotomy cross sectional level and the total knee arthroplasty cross sectional level. In two knees at the high tibial osteotomy cross sectional level and in two knees at the total knee arthroplasty cross sectional, level the artery moved closer to the posterior tibia with knee flexion. Even with the effect of gravity included, knee flexion does not guarantee removal of the popliteal vessels from potential harm during surgery of the knee.

Arthroplasty, Replacement, Knee↗
PubMed1999

Joint line restoration after revision total knee arthroplasty.

In 99 patients, 107 knee replacements were revised in two centers by two surgeons using a single revision total knee arthroplasty system. A retrospective radiographic review of joint line position before and after revision total knee arthroplasty was made, and compared with the joint line position before primary knee arthroplasty. Prospectively collected Knee Society Clinical Rating Scores were correlated with radiographic findings. The joint line position in unreplaced knee replacements averaged 16 mm, and the joint line position in knee replacements before revision surgery averaged 17 mm. The joint line was elevated by the revision total knee arthroplasty in 85 of 107 knees (79%). After the revision total knee replacement, the joint line elevation averaged 24 mm. The Knee Society Clinical Rating Score after revision surgery averaged 131 points. If the joint line position was elevated more than 8 mm, the Knee Society Clinical Rating Score averaged 125 points, if the joint line was elevated less than 8 mm, the score averaged 141 points. Joint line elevation after revision total knee replacement is a problem. Excessive elevation may result in worse clinical outcomes. Distal femoral augments should be used more often and with greater thicknesses. Standard implants used for revision surgery should have increased distal dimensions.

Aged↗
PubMed1999

Medium-term results of a mobile bearing total knee replacement.

Mobile bearing total knee arthroplasty kinematically allows the advantages of large and congruent surface contact and low contact pressures, while preserving flexion, extension, and rotation in knee motion. In allowing for these degrees of freedom, the interface between bone and component also is protected from high stress. The Self Aligning I total knee arthroplasty initially was implanted in patients after its development at the authors' institution in 1990. Between 1990 and 1994, 141 patients with osteoarthritis of the knee underwent 172 total knee replacements using this system. At average followup of 5.6 years (range, 5-8 years), clinical results using this system showed a 94% satisfaction rate (good or very good). Two revision surgeries have been performed for polyethylene wear, with none of the remaining knees showing evidence of discernible wear. Complications included four cases of deep infection, four cases where a press fit femoral component failed (nonporous coated) and the patients required revision surgery, four traumatic fractures (three patellar and one supracondylar), one popliteal artery occlusion, and one revision for stiffness. Three patients required manipulation under anesthesia for arthrofibrosis. Kaplan-Meier survival curves show the probability of survival to be 91.7%, with revision surgery for any reason as an end point, and 98.8% for revision surgery because of polyethylene wear as an end point. Following the initial learning curve with this prosthesis, the medium term results using this system show maintenance of clinical success. No progressive evidence of polyethylene wear with time has been found, supporting the concept of mobile bearing arthroplasty in extending the service life of total knee arthroplasty.

Aged↗
PubMed1999

Hip revision arthroplasty. Approach to the femoral side.

Total hip arthroplasty has proven to be a highly successful procedure but with its increased use in elderly patients and in young patients with high physical demands, there are an increasing number of joints requiring revision. Many factors, including loss of bone stock, joint instability, infection, fracture, trochanteric nonunion, and difficulty in implant or cement removal, make revision of the femoral component challenging to the surgeon. To address these factors and to achieve the goals of revision surgery, several key questions should be addressed. What exposure should be used? How can the implant be removed? What type of reconstruction should be used and which implant should be chosen? How can stable fixation be achieved? How can the bone defects be treated? The approach that the authors recommend to the femoral component in revision hip arthroplasty is outlined, taking into consideration each of the questions above. The classification system used by the authors for femoral bone defects present at the time of revision arthroplasty has four categories based on the integrity of the proximal cancellous bone and the cortical tube, which is used to select the technique of reconstruction. The literature on techniques for revision of a failed femoral component is reviewed.

Arthroplasty, Replacement, Hip↗