Are current thrombo-embolic prophylaxis guidelines applicable to unicompartmental knee replacement?

Delayed pulmonary embolism after unicompartmental knee arthroplasty: A case report

INTRODUCTION

Although venous thromboembolism (VTE) is relatively rare after unicompartmental knee arthroplasty (UKA), symptomatic pulmonary embolism (PE) can be fatal. Whether routine thromboprophylaxis or thrombolytic treatment is necessary for patients undergoing UKA remains unclear. Here, we present a case of delayed pulmonary embolism after UKA.

PATIENT CONCERNS

A 57-year-old women underwent cemented UKA for left localized medial knee pain. There were no risk factors of VTE besides high BMI before surgery. 2 months after surgery, the patient presented with dyspnea and palpitation, and these symptoms could not be alleviated after rest.

DIAGNOSIS

An arterial blood gas analysis showed decreased PO2, SO2 and PCO2. Pulmonary CTA showed multiple pulmonary embolism in the trunk of the right lower pulmonary artery and the branch of the left lower pulmonary arteries. The final diagnosis was delayed pulmonary embolism after UKA.

INTERVENTIONS

Urokinase thrombolysis was administered intravenously. Low molecular weight heparin and warfarin were prescribed for anticoagulation.

OUTCOMES

The patient's symptoms abated, and chest CTA showed that the pulmonary embolism had dissolved. No further thrombosis has been observed for more than 6 years.

CONCLUSIONS

We presented an unusual case of delayed pulmonary embolism after UKA. Despite the low incidence, its life-threatening nature makes it imperative for surgeons to be well-informed about thrombosis and pay more attention to its prevention strategies.

Quality of life outcomes in patients undergoing knee replacement surgery: longitudinal findings from the QPro-Gin study

Background

Many patients report postoperative pain, limited improvement in physical function and poor quality of life (QOL) after knee replacement surgery. Our study uses baseline predictors of change to investigate the QOL of patients with knee osteoarthritis 3-months after knee replacement surgery.

Methods

A prospective observational study was designed to evaluate patients (n = 132) scheduled for uni-compartmental or total knee replacement surgery who were assessed at baseline (preoperatively) and 3-months after. Physical and mental endpoints based on the component scores of the SF-12 and on the Western Ontario and McMaster Universities Arthritis (WOMAC) index were used to investigate patients’ QOL. Generalised estimating equation methodology was used to assess patients’ baseline characteristics (age, sex, education, body mass index (BMI), comorbidity, depressive symptoms, cognitive impairment, smoking/alcohol and type of surgery), the study endpoints and their changes over a 3-month post-surgery period. Stratified analyses by rehabilitation status after discharge were performed.

Results

Longitudinal data analysis showed that the baseline factors associated with improvement in general QOL at the 3-month post-surgery assessment were higher BMI, a high comorbidity, total (as opposed to unicompartmental) knee replacement and low education level. Data analysis of the patients who underwent rehabilitation after discharge revealed that the current smokers’ physical QOL worsened over time. The general QOL was unchanged over time in the presence of depressive symptomatology.

Conclusions

These findings underline the importance of using comprehensive assessment methods to identify factors affecting functionality and QOL, and developing interventions to improve the health/wellbeing of patients after knee replacement.

Changes in Markers of Thrombin Generation and Interleukin-6 During Unicondylar Knee and Total Knee Arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is associated with a risk of thromboembolism requiring routine thromboprophylaxis, but there is debate about the risk with unicondylar knee arthroplasty (UKA) as it is a more minor procedure. We sought to investigate the relative risk of thromboembolism with UKA compared to TKA and one-staged bilateral TKA (BTKA) by measuring the increase in circulating biochemical markers of thrombin generation during the procedures. Degree of surgical trauma was also assessed by measuring interleukin-6, a marker of metabolic injury.

METHODS

We prospectively studied a total of 75 patients: 25 patients undergoing UKA, unilateral TKA, and BTKA, respectively. All patients had surgery performed with tourniquet and received no tranexamic acid. Blood samples were taken during surgery and assayed for circulating markers of thrombin generation: prothrombin fragment 1+2 (F1+2) and thrombin-antithrombin complexes plus interleukin-6.

RESULTS

Thrombin-antithrombin complexes, increased during all time points (P < .001) but was not significantly different between surgical treatment groups. F1+2 also rose significantly during surgery, with no significant difference between UKA and TKA. There was, however, a significant difference in F1+2 between BTKA and UKA or TKA (P < .02). Interleukin-6 rose minimally with UKA but rose significantly with TKA and BTKA (P < .001).

CONCLUSION

Based on these data of circulating biochemical markers, patients undergoing UKA are at similar risk of thromboembolism with respect to TKA despite a lower index of metabolic injury. We believe that UKA patients should receive thromboprophylaxis comparable to TKA patients.

Unicompartmental Knee Arthroplasty vs Total Knee Arthroplasty for Medial Compartment Arthritis in Patients Older Than 75 Years: Comparable Reoperation, Revision, and Complication Rates

BACKGROUND

Prior studies comparing unicompartmental knee arthroplasty (UKA) with total knee arthroplasty (TKA) in the elderly are limited by heterogeneity in arthritic disease patterns and patient selection. We report the results of UKA and TKA in patients 75 years and older with isolated medial compartmental arthritis, with special emphasis on immediate postoperative recovery, complications, reoperation rates, and implant survivorship at midterm follow-up.

METHODS

A retrospective review was performed of all patients 75 years and older who underwent UKA or TKA at our institution between 2002 and 2012. All TKA preoperative X-rays were reviewed by a blind observer to identify knees with isolated medial compartmental arthritis considered acceptable candidates for UKA. Patients with less than 2 years of follow-up, flexion contracture greater than 10°, and rheumatoid arthritis were excluded. The final sample included 120 UKA (106 patients) and 188 TKA (170 patients) procedures. Patient records were reviewed to determine early postoperative recovery, complications, reoperations for any reason, and implant survivorship.

RESULTS

UKA patients experienced significantly shorter operative time, shorter hospital stay, lower intraoperative estimated blood loss, lower postoperative transfusions, greater postoperative range of motion, and higher level of activity at time of discharge. Two UKA and 2 TKA patients required revision surgery. There was no statistically significant difference in postoperative Knee Society Scores. There were no differences in 5-year survivorship estimates.

CONCLUSION

Due to its less invasive nature, patients older than 75 undergoing UKA demonstrated faster initial recovery when compared to TKA, while maintaining comparable complications and midterm survivorship. UKA should be offered as an option in the elderly patient who fits the selection criteria for UKA.

Deep Venous Thrombosis Prophylaxis After Unicompartmental Knee Arthroplasty: A Prospective Study on the Safety of Aspirin

BACKGROUND

Although venous thromboembolism is one of the leading causes of morbidity after knee arthroplasty, little data exist on the risk of deep venous thrombosis (DVT) after unicompartmental knee arthroplasty (UKA).

METHODS

We prospectively enrolled 112 patients undergoing UKA to determine the incidence of DVT utilizing aspirin 325 mg twice a day (BID) for 4 weeks postoperatively as DVT prophylaxis. The data were compared with a recent randomized controlled trial of patients undergoing total knee arthroplasty utilizing aspirin and Lovenox in conjunction with pneumatic compression devices.

RESULTS

One patient (0.9%) had an asymptomatic DVT, and none developed clinical symptoms of either DVT or pulmonary embolus. The incidence of asymptomatic and symptomatic DVT was 0.9% and 0%, respectively.

CONCLUSION

Our data suggest that 325 mg of aspirin BID for 4 weeks results in a very low risk of DVT for patients undergoing UKA.

Is Routine Thromboprophylaxis Needed in Korean Patients Undergoing Unicompartmental Knee Arthroplasty?

This study was undertaken to determine the prevalence and the natural course of venous thromboembolism (VTE) without thromboprophylaxis to ascertain whether routine thromboprophylaxis is necessary following unicompartmental knee arthroplasty (UKA) in Korean patients. The medical records and multidetector row computed tomography (MDCT) imaging of the consecutive 77 UKAs in 70 patients were reviewed. In all patients, MDCTs were undertaken preoperatively and at 1-week after surgery, and VTE symptoms were evaluated. At postoperative 6-months, follow-up MDCTs were undertaken in all patients in whom VTEs were newly detected after surgery. VTE lesions were newly detected in 18 (26%) of the 70 patients. However, none of the patients complained of VTE-related symptoms and MDCT demonstrated that all VTEs were small and involved limited portion without lower leg edema or pleuroparenchymal complication. At the 6-month follow up MDCT, all types of VTEs were shown to be completely resolved, regardless of their location. All of the VTE lesions maintained an asymptomatic status for 6-month after surgery. VTE following UKA in Korean patients who do not receive thromboprophylaxis seems to occur frequently, but all of the VTEs are clinically insignificant and all VTEs are spontaneously regressed. Routine thromboprophylaxis or thrombolytic treatment in Korean patients undergoing UKA may not be necessary.

Oxford unicompartmental knee arthroplasty versus age and gender matched total knee arthroplasty - functional outcome and survivorship analysis

We compared the medium-term outcomes of age and gender matched patients with unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA). We retrospectively reviewed the pain, function and total knee society scores (KSS) for 602 UKAs and age and gender matched TKAs between 2001 and 2013. Function scores remained significantly better in UKAs from preoperative until 3years follow up. The change of function scores was not significantly different. TKAs performed better than UKAs for pain scores. Total KSS for both groups were not significantly different in the study. Fewer medical complications were reported in UKA group. 6.30% of UKAs and 2.99% of TKAs were revised. The theoretical advantages of UKA were not borne out, other than in immediate postoperative complications.

Bone loss during revision of unicompartmental to total knee arthroplasty: an analysis of implanted polyethylene thickness from the National Joint Registry data

Using the National Joint Registry (UK) database, we compared the thickness of polyethylene (PE) and the level of constraint used during primary total knee arthroplasty (TKA) versus the revision of unicondylar knee arthroplasty (UKA) to TKA. A total of 251,803 TKA procedures and 374 revision UKA-TKA procedures between 2003 and 2009 were reviewed. The commonest PE size used in TKA was 10mm, compared to 12.79 mm in the revision group. The use of constrained knee implant was required in 2.15% of primary TKA and 4.19% of UKA to TKA revisions. The revision of UKA to TKA is a more complex procedure compared to primary TKA, with a higher incidence of using constrained implants and thicker PE inserts. These findings may be useful for surgeons in their decision making.