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Biomedical subjects

Paul A Lotke

Publications and source records attributed to Paul A Lotke.

At least 19 recordsLinked to original sources
PubMed2006

Technique for impaction bone grafting of large bone defects in revision total knee arthroplasty.

Impaction bone grafting is an important tool in managing the irregularly sized and shaped bone defects observed in revision total knees. The technique is described in detail and includes tightly packing cancellous bone chips about an intramedullary stem and into the periprosthetic bone defects, then fully cementing a component in place. If needed, wire mesh can be used to contain bone defects. Results to date in 42 patients with 2 to 7 years of follow up are reported. They show the average flexion was 111 degrees; the final Knee Society score was 89 points, and there were no mechanical failures. There were 2 infections and 2 late periprosthetic fractures. The results have been encouraging, and this technique remains our procedure of choice for managing large bone defects in revision knee surgery.

Aged↗
PubMed2006

What would you do? Case challenges in knee surgery.

Six cases representing a variety of orthopedic issues were presented to a panel of senior surgeons. These included the following: (1) developmental patella baja with degenerative arthritis, (2) high valgus knee with attenuated medial collateral ligament, (3) degenerative arthritis with near-ankylosis, (4) depressed tibial plateau fracture with degenerative arthritis, (5) degenerative arthritis with laterally dislocating patella, and (6) degenerative arthritis with distal femoral malunion.

Aged↗
PubMed2006

Impaction grafting for bone defects in revision total knee arthroplasty.

UNLABELLED: Bone loss in revision total knee arthroplasty is a complex and challenging problem. Frequently, the defects encountered are irregular in size and shape. Since 1998, we have been using impaction bone allografting for constrained and unconstrained defects in revision total knee arthroplasty. We prospectively studied the mid-term results of 48 consecutive revision total knee arthroplasties with substantial bone loss treated with impaction allograft. Average followup was 3.8 years. Knee Society scores improved from a preoperative average of 57.0 to a postoperative average of 89.8 points (p < 0.001). Knee Society functional scores improved from a pre-operative average of 52.3 to a postoperative average of 80.3 points (p < 0.001). There have been no mechanical failures of the revisions and all radiographs have shown incorporation and remodeling of the bone graft. There were six complications out of the 42 revisions available for followup (14%); two periprosthetic fractures, one early infection salvaged with irrigation and antibiotics, one late infection resulting in fusion, and two patellar clunk syndromes. Though time consuming and technically demanding, impaction grafting for bone loss in revision total knee arthroplasty has excellent durability and versatility. It has become our preferred technique for the management of substantial bone loss in revision total knee arthroplasty. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series).

Adult↗
PubMed2006

The benefit of aspirin chemoprophylaxis for thromboembolism after total knee arthroplasty.

The threat of thromboembolic events after total knee arthroplasty has been substantially reduced during the past decade. Currently, the risk of fatal pulmonary embolism is approximately 0.1%. This is due to a confluence of changes in our medical practices, including early mobilization, less traumatic surgery, increased use of regional anesthesia, pneumatic compression devices, and chemoprophylactic agents. Because many chemoprophylactic agents are associated with an increased risk of bleeding, we have chosen aspirin as our preferred method of chemoprophylaxis. This study seeks to determine if aspirin is as effective as newer chemoprophylactic agents as judged by the prevalence of fatal or nonfatal pulmonary embolus, readmission for deep venous thrombosis, and risk of bleeding. Aspirin was the principle chemoprophylactic agent for 3473 consecutive patients having total knee arthroplasty. All patients were followed for a minimum of 6 weeks. There were nine deaths: two from pulmonary embolism, five cardiac events, one stroke, and one fat embolism. Three cardiac-related deaths occurred in patients for whom pulmonary embolism could not definitively be ruled out. Therefore, the best case and worst case scenarios for fatal pulmonary embolism were 0.06% and 0.14%, respectively. Thirteen patients underwent reoperation for hematoma (0.4%). Therefore, we have demonstrated aspirin combined with early mobilization, regional anesthesia, foot pumps, and improved surgical techniques is safer than and equally efficacious as other chemoprophylaxis agents.

Arthroplasty, Replacement, Knee↗
PubMed2006

Postthrombotic syndrome after asymptomatic deep vein thrombosis following total knee and hip arthroplasty.

Lower extremity deep vein thrombosis (DVT) is relatively common after total knee arthroplasty (TKA) and total hip arthroplasty (THA). In this study, we sought to identify whether post-thrombotic syndrome is a significant risk in patients with asymptomatic DVT after TKA and THA. Included in the study were 186 patients (203 lower extremities) who had undergone routine lower extremity venography after TKA or THA between 1989 and 1993. Patients were contacted a minimum of 7 years after surgery. Postoperative varicose veins occurred in 8% of limbs without DVT compared with 12% of limbs with DVT. Hyperpigmentation occurred in 13% of limbs without DVT and in 16% and 18% of limbs with proximal and distal DVT, respectively. Swelling occurred in 6% of limbs without DVT, in 8% of limbs with proximal DVT, and in 12% of limbs with distal DVT. None of these differences was statistically significant, and there were no differences for proximal versus distal DVT. There was no significant increase in risk for postthrombotic syndrome after asymptomatic proximal or distal DVT after TKA or THA.

Arthroplasty, Replacement, Hip↗
PubMed2005

Deep venous thrombosis prophylaxis: better living through chemistry--in opposition.

The best prophylactic regimens for thromboembolic disease continue to be debated despite years of investigation. The surgeon must balance the clinical risks and benefits. A decision depends on accurate data and our ability to balance the risks of fatal pulmonary embolism (PE) to the risk of bleeding. The current risk for fatal PE is 0.1% with most current prophylactic regimes. The risk of perioperative bleeding increases 1.8% to 5.2% with low molecular weight heparins or warfarin and generally is dose dependent. Most of the current prophylactic recommendations are based on the presence or absence of deep venous thrombosis (DVT). However, the correlation between the presence of a DVT and the risk of PE is low and inconsistent. Therefore, DVT may not be an accurate surrogate marker for the patient at risk after total joint surgery. Our experience with 2800 consecutive total knee arthroplasty patients, using aspirin as our principle agent, shows a fatal PE risk of 0.1% and a low risk of bleeding. Therefore, our current recommendation is aspirin.

Anticoagulants↗
PubMed2005

Patellofemoral arthroplasty: the third compartment.

Isolated arthritis on the patellofemoral articulation has received minimal attention in the past. It is now recognized to be relatively common, especially in women. Treatment alternatives such as patellectomy, unloading osteotomies, debridement, and cartilage transplant have not offered long-term sustainable benefits. Therefore, there is a need for a reliable patellofemoral arthroplasty. The current indications for surgery include middle-aged patients with isolated patellofemoral arthritis without severe maltracking, inflammatory arthritis, crystalline arthropathy, femorotibial arthritis, or high demands. Reports show 60% to 80% good-to-excellent results in the short term and midterm. The main problems with patellofemoral arthroplasty have been patellar instability and patellar edge loading on the condylar cartilage in flexion. Newer designs are addressing both issues and are leading to improved results.

Arthritis↗
PubMed2005

Stiffness after total knee arthroplasty.

BACKGROUND: Stiffness is an uncommon but disabling problem after total knee arthroplasty. The prevalence of stiffness after knee replacement has not been well defined in the literature. In addition, the outcomes of revision surgery for a stiff knee following arthroplasty have not been evaluated in a large series of patients, to our knowledge. The purposes of this study were to define the prevalence of stiffness after primary total knee arthroplasty and to evaluate the efficacy of revision surgery for treatment of the stiffness. METHODS: We defined a stiff knee as one having a flexion contracture of 15 degrees and/or <75 degrees of flexion. Two separate groups were evaluated. First, the results of 1000 consecutive primary total knee replacements were reviewed to determine the prevalence of stiffness. Second, the results of fifty-six revisions performed because of stiffness, sometimes associated with pain or component loosening, after primary total knee arthroplasty were evaluated. RESULTS: The prevalence of stiffness was 1.3%, at an average of thirty-two months postoperatively. The patients with a stiff knee had had significantly less preoperative extension and flexion than did those without a stiff knee (p < 0.0001). There were no significant differences in age, gender, implant design, diagnosis, or the need for lateral release between the patients with and without stiffness. The second cohort, of knees revised because of stiffness, were followed for an average of forty-three months. The mean Knee Society score improved from 38.5 points preoperatively to 86.7 points at the time of follow-up; the mean Knee Society function score, from 40.0 to 58.4 points; and the mean Knee Society pain score, from 15.0 to 46.9 points. The mean flexion contracture decreased from 11.3 degrees to 3.2 degrees , the mean flexion improved from 65.8 degrees to 85.4 degrees , and the mean arc of motion improved from 54.6 degrees to 82.2 degrees . The arc of motion improved in 93% of the knees, and flexion increased in 80%. Extension improved in 63%, and it remained unchanged in 30%. CONCLUSIONS: The prevalence of stiffness in our series of 1000 primary knee arthroplasties was 1.3%. Revision surgery was a satisfactory treatment option for stiffness, as the Knee Society scores improved, the flexion contractures diminished, and 93% of the knees had an increased arc of motion. However, the results suggest that the benefits are modest.

Arthroplasty, Replacement, Knee↗
PubMed2004

Lateral retinacular release as a function of femoral component rotation in total knee arthroplasty.

A consensus exists in the orthopaedic community that proper rotational placement of components may reduce the need for lateral release. This study compares the rates and results of lateral release before and after femoral component placement was defined by the transepicondylar axis (TEA). Between 1990 and 1991, 104 primary total knee arthroplasties (TKA) were reviewed during which equal amounts of bone from the posterior femoral condyles were removed. In this group, the lateral release incidence was 24% for varus deformities and 33% for valgus deformities. When the femoral component was externally rotated approximating the TEA, a review of 246 primary TKAs performed between 1998 and 1999 showed lateral release rates of 7% in varus deformities and 29% in valgus deformities. This study documents the statistically significant decline in the lateral release rate with external rotation of the femoral component during TKA in varus deformities (P<.0001), and a decreasing trend in valgus knees (P =.09).

Adult↗
PubMed2004

Spontaneous osteonecrosis of the knee: tibial plateaus.

Spontaneous osteonecrosis of the medial tibial plateau is less recognized than osteonecrosis of the medial femoral condyle, but it presents in a similar manner. These patients have a sudden onset of pain on the medial side of the knee associated with a spectrum of MRI changes in the tibial subchondral bone. The small lesions can resolve with only minimal residual scar remaining in the subchondral zone. If the lesion is large, it can collapse or show MRI changes of osteonecrosis. Recognition of this problem may help avoid unnecessary intra-articular surgical intervention.

Aged↗
PubMed2004

Response bias: effect on outcomes evaluation by mail surveys after total knee arthroplasty.

BACKGROUND: Mail survey questionnaires are increasingly being used for follow-up evaluations to gauge satisfaction and performance after total joint arthroplasty. Responses to questionnaires are subject to a variety of possible biases. We evaluated response behavior in a mail survey of patients who had had a total knee arthroplasty. METHODS: A ten-question survey that evaluated satisfaction, general health, and Knee Society knee function and clinical scores was mailed to 472 patients who had undergone consecutive primary total knee arthroplasties from 1996 to 1998. The 83% who responded were stratified as early, late, and repeat-mailing responders. The 17% who failed to respond after two mailings were considered nonresponders. All of the nonresponders were eventually contacted. The groups were compared with regard to their scores at the preoperative office visit, at the most recent office visit, and on the mail survey. RESULTS: In the mail survey, the patients who responded earliest gave the highest satisfaction ratings and the nonresponders gave the poorest ratings (p < 0.001). Similarly, the mean Knee Society knee score (and standard deviation) was significantly higher for the early responders (82.7 +/- 19.0) than for the nonresponders (66.9 +/- 16.0), as was the mean function score (68.8 +/- 24.1 compared with 48.4 +/- 12.5) and the mean pain score (39.8 +/- 13.9 compared with 27.0 +/- 9.7) (all p < 0.0001). The change between the preoperative and mail survey Knee Society knee scores was significantly higher for the early responders (46.12 +/- 25.71) than for the nonresponders (28.45 +/- 23.62), as was the change in the mean function scores (18.87 +/- 22.52 compared with 5.34 +/- 20.05) and the change in the mean pain scores (23.57 +/- 17.76 compared with 10.67 +/- 12.93) (all p < 0.0001). CONCLUSIONS: Patients who do not respond to mail surveys used for follow-up are unique in that they report significantly poorer outcomes than do responders. This potential response bias should be considered in all follow-up analyses. Because it may be difficult to attain 100% response rates in very large series of patients, division of the study cohort into more manageable segments is advised to achieve a more complete response rate. The assessment of patients who are lost to follow-up is an important and necessary component in the accurate analysis of outcomes after arthroplasty.

Adult↗
PubMed2004

Stiffness after total knee arthroplasty. Prevalence of the complication and outcomes of revision.

BACKGROUND: Stiffness is an uncommon but disabling problem after total knee arthroplasty. The prevalence of stiffness after knee replacement has not been well defined in the literature. In addition, the outcomes of revision surgery for a stiff knee following arthroplasty have not been evaluated in a large series of patients, to our knowledge. The purposes of this study were to define the prevalence of stiffness after primary total knee arthroplasty and to evaluate the efficacy of revision surgery for treatment of the stiffness. METHODS: We defined a stiff knee as one having a flexion contracture of >/=15 degrees and/or <75 degrees of flexion. Two separate groups were evaluated. First, the results of 1000 consecutive primary total knee replacements were reviewed to determine the prevalence of stiffness. Second, the results of fifty-six revisions performed because of stiffness, sometimes associated with pain or component loosening, after primary total knee arthroplasty were evaluated. RESULTS: The prevalence of stiffness was 1.3%, at an average of thirty-two months postoperatively. The patients with a stiff knee had had significantly less preoperative extension and flexion than did those without a stiff knee (p < 0.0001). There were no significant differences in age, gender, implant design, diagnosis, or the need for lateral release between the patients with and without stiffness. The second cohort, of knees revised because of stiffness, were followed for an average of forty-three months. The mean Knee Society score improved from 38.5 points preoperatively to 86.7 points at the time of follow-up; the mean Knee Society function score, from 40.0 to 58.4 points; and the mean Knee Society pain score, from 15.0 to 46.9 points. The mean flexion contracture decreased from 11.3 degrees to 3.2 degrees, the mean flexion improved from 65.8 degrees to 85.4 degrees, and the mean arc of motion improved from 54.6 degrees to 82.2 degrees. The arc of motion improved in 93% of the knees, and flexion increased in 80%. Extension improved in 63%, and it remained unchanged in 30%. CONCLUSIONS: The prevalence of stiffness in our series of 1000 primary knee arthroplasties was 1.3%. Revision surgery was a satisfactory treatment option for stiffness, as the Knee Society scores improved, the flexion contractures diminished, and 93% of the knees had an increased arc of motion. However, the results suggest that the benefits are modest.

Adult↗
PubMed2003

Limited success with open debridement and retention of components in the treatment of acute Staphylococcus aureus infections after total knee arthroplasty.

The purpose of this study was to review our experience in treating acute gram-positive infections after total knee arthroplasty with debridement, component retention, and intravenous antibiotics. Thirty-one total knee arthroplasties with acute gram-positive infections, seen at our institution over a 10-year period, were treated with open debridement and component retention. Eleven (35%) of 31 patients successfully retained their components at most recent follow-up, without ongoing infection (mean, 4 years; range, 2-10 years). Only one (8%) of the 13 patients infected with Staphylococcus aureus was successfully treated, compared with 10 (56%) of 18 patients with either Staphylococcus epidermidis or a streptococcal species. The difference between these groups is statistically significant (P=.007). The high failure rate of debridement and component retention suggests that immediate component removal should be considered in the presence of acute S. aureus infection in total knee arthroplasty.

Acute Disease↗
PubMed2003

Use of a trabecular metal patella for marked patella bone loss during revision total knee arthroplasty.

This study evaluates the short-term results following patellar resurfacing with a trabecular metal patella shell in the setting of marked patellar bone loss at the time of revision total knee arthroplasty (TKA). Twenty consecutive patients undergoing revision TKA with the use of a trabecular metal patella were evaluated at a mean 23-month follow-up. All patients had marked patellar bone loss at surgery precluding resurfacing with a standard cemented patellar button. Results were good or excellent in 17 of 20 patients. There were no displacements of any trabecular metal patella shells, and the fixation appeared excellent despite the poor quality of bone remaining. Complications included 3 patients with polar patella fractures postoperatively. Qualitatively, these results compare favorably with patellar resection arthroplasty in this setting.

Adult↗