Orthopaedic Surgery Knee
no significant association was found with the type of DVT chemoprophylaxis used in the perioperative setting. Thus, it may simply be the magnitude of anticoagulation present (either inherent or iatrogenic) rather than the specific means for achieving this that is important, which is also somewhat intuitive.
In prior publications,12,15 differences in bleeding risks have been
identified based on the type and timing of chemoprophylaxis used for DVT management after TKA. In a recent meta-analysis by Brookenthal et al., however, no statistically significant differences were identified between aspirin, low molecular weight heparin, subcutaneous heparin or warfarin.10
The results of this meta-analysis support the findings from the study at the Mayo Clinic.
Despite this, in the meta-analysis trends were noted with aspirin and warfarin appearing somewhat less likely to cause bleeding complications than low molecular weight heparin or subcutaneous heparin.6,10
Again, this is somewhat intuitive. It is likely to be related to the speed with which the anticoagulation effect occurs in the post- operative period, as well as the magnitude of the anticoagulation effect that can be achieved with the varying agents.
In the 2008 American College of Chest Physicians guidelines regarding venous thromboembolic event (VTE) prophylaxis after TKA, a review of the published randomised studies comparing the efficacy of different agents in the post-operative period is presented.12
In the review, there
appears to be a general trade-off between the rates of DVT formation and bleeding complications.12
Comparing warfarin with low molecular
Furthermore, when comparing fondaparinux with low molecular weight heparin the same general principle was identified. There were lower VTE rates but higher bleeding rates, especially if the fondaparinux was administered within six hours of surgery.12
weight heparin, warfarin was considered less efficacious at preventing DVT but was associated with lower bleeding complications (2.7 versus 4.5%, p=0.02).12
These
findings further support the general concept that more aggressive anticoagulation will result in higher bleeding complications.
Outcomes Following Surgical Evacuation of Post-operative Haematomas
Not only do ambiguities exist in the incidence and aetiology of haematoma formation because of the relative paucity of conclusive information, but little has been reported about the long-term sequelae of post-operative haematomas after TKAs that require early re-operation.
In the Mayo Clinic report, the long-term sequelae of haematoma formation requiring surgical evacuation were examined.6
There were primary and secondary end-points The patients
that had undergone surgical evacuation of a haematoma were compared with the remaining >17,000 knees that were not associated with this complication.6
for both groups. Primary end-points were any cases of major surgery following the initial evacuation, including prostheses removal, muscle flap, skin grafting and amputation. Secondary end-points were any cases of deep infection below the fascia.6
Of the 42 knees that underwent re-operation for treatment of a post- operative haematoma, five patients (11.9%) ultimately required additional major surgery compared with 200 of 17,742 (1.1%) knees that had not developed a haematoma requiring surgical evacuation.6 Furthermore, the five knees (11.9%) that had undergone re-operation
62
Based on these limited data, it appears that the consequences of developing a haematoma significant enough to require re-operation in the immediate post-operative period following TKA extend well beyond the re-operation and prolonged hospitalisation that occurs immediately. They include approximately a 15% risk of experiencing additional, potentially disabling complications.6
In distinction to the significant problems noted in the above series, Weiss and Krackow reported good results following early debridement of patients who had persistent wound drainage after TKA.7
In their
series, two out of eight patients had positive cultures at the time of the debridement, but all patients were successfully treated without the need for subsequent re-operations.7
Compared with the report from Mayo Clinic, however, only three of the eight cases had bloody drainage and an arthrotomy dehiscence reflective of a draining deep haematoma.7
The remaining five patients
had serous drainage. Of these, four did not demonstrate any dehiscence of the arthrotomy.7
superficial debridement and closure was performed.7
When the fascia was intact, only The two series
are therefore not directly comparable. Based on the success of early surgical intervention, Weiss and Krackow advocated early return to surgery in cases of significant persistent early wound drainage.7
In a similar study involving persistent wound drainage after hip and knee replacement, Jaberi et al.19 with those reported by Galat et al.6
reported findings more consistent In their series, a 20% re-operation
rate following early debridement for persistent early wound drainage was noted.19
Many of these cases involved patients who were subsequently diagnosed with deep infection.19
In part, this discrepancy between the approximately 10–15% rate of major re-operation noted by Galat et al. and the 20% rate noted by Jaberi et al. reflects the differences in the study populations.6,19
In
the study by Galat et al., all cases were felt to represent sterile haematomas where cases suspicious for early deep prosthetic infection had been excluded.6,19
Furthermore, no cases of simple
superficial wound problems were included in the series by Galat et al.6 In comparison with this, the series reported by Jaberi et al. included a much more heterogeneous population.19
Importantly, confirming the recommendations of Wiess and Krackow, Jaberi et al. identified that patients with persistent wound drainage who underwent re-operation within five days of the index joint replacement had significantly lower subsequent complications.7,19 Based on these limited studies it therefore appears that in cases with persistent early bloody drainage, which in Weiss and Krackow’s series was always indicative of arthrotomy dehiscence and drainage of a deep haematoma, early surgical debridement within five to seven days should be considered.7
It is likely that the high subsequent complication rates following initial surgical debridement of the haematoma noted in the work by Galat et
EUROPEAN MUSCULOSKELETAL REVIEW for a haematoma ultimately developed deep infection.6 This was
compared with 324 of 17,742 knees (1.8%) that had not developed a post-operative hematoma requiring re-operation. Three knees were common to both end-points, therefore seven knees (17%) experienced a serious sequelae.6
These findings were significantly higher for the knees that had required re-operation (p<0.001).6
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