Orthopedics

Feature Article 

Outcomes of Prophylactic Negative Pressure Wound Therapy in Knee Arthroplasty

Andrew J. Curley, MD; Elizabeth B. Terhune, BS; Anthony T. Velott, MD; Evan H. Argintar, MD

Abstract

Negative pressure wound therapy is becoming more commonly used to prevent wound complications in joint arthroplasty, although few studies have assessed its outcomes compared with those of a traditional dry sterile dressing. This retrospective study assessed complications that required return to the operating room in a cohort of patients who received a dry sterile dressing (n=159) vs negative pressure wound therapy (n=32). There were significantly more overall complications (P=.0293) in the dry sterile dressing group (23.3%) compared with the negative pressure wound therapy group (6.3%); however, these findings were not statistically significant when each individual complication was compared separately. The infection rate in the dry sterile dressing group and the negative pressure wound therapy group was 5.7% and 0%, respectively (P=.3607). A larger, prospective study is needed to confirm the lower infection rate and before any definitive conclusions can be reached. [Orthopedics. 2018; 41(6):e837–e840.]

Abstract

Negative pressure wound therapy is becoming more commonly used to prevent wound complications in joint arthroplasty, although few studies have assessed its outcomes compared with those of a traditional dry sterile dressing. This retrospective study assessed complications that required return to the operating room in a cohort of patients who received a dry sterile dressing (n=159) vs negative pressure wound therapy (n=32). There were significantly more overall complications (P=.0293) in the dry sterile dressing group (23.3%) compared with the negative pressure wound therapy group (6.3%); however, these findings were not statistically significant when each individual complication was compared separately. The infection rate in the dry sterile dressing group and the negative pressure wound therapy group was 5.7% and 0%, respectively (P=.3607). A larger, prospective study is needed to confirm the lower infection rate and before any definitive conclusions can be reached. [Orthopedics. 2018; 41(6):e837–e840.]

Negative pressure wound therapy was first described in 1997 for acute, subacute, and chronic wounds.1,2 The proposed mechanism of action for wound healing included the removal of chronic edema and an accelerated rate of tissue granulation. Although initially developed in the field of plastic surgery, the use of negative pressure wound therapy has been incorporated into other fields, including general surgery, vascular surgery, cardiothoracic surgery, and orthopedics. Stannard et al3 supported the use of negative pressure wound therapy in orthopedic trauma with a prospective, randomized control trial showing a decreased infection rate in open fractures treated with negative pressure wound therapy.

Regarding joint arthroplasty, several early case series described negative pressure wound therapy in the management of prosthetic joint infections.4–6 However, more recent studies have examined the effects of prophylactic negative pressure wound therapy to prevent wound complications and infections in the immediate postoperative period following hip and knee arthroplasty.7–9 Given that these studies reported both beneficial and detrimental patient outcomes, no clear consensus has been reached as to the benefit of negative pressure wound therapy for joint arthroplasty. The purpose of this study was to assess if prophylactic negative pressure wound therapy, applied to the surgical incision in the operating room at the end of the case, affected the rate of complications following knee arthroplasty.

Materials and Methods

A series of 192 consecutive primary total knee arthroplasties (TKAs), unicompartmental knee arthroplasties (UKAs), and unicompartmental knee arthroplasties with patellofemoral arthroplasties (UniPat) performed by the senior author (E.H.A.) between December 2012 and March 2017 were identified. A retrospective chart review was performed to collect demographic and operative data. In all patients, the primary surgical incision was closed with Vicryl (Ethicon, Somerville, New Jersey) suture, with or without additional staples. During the time line of this study, the senior author did not change any other significant aspects of the perioperative protocol, including venous thromboembolism prophylaxis. Operative reports were reviewed to determine if the incision was dressed with a standard sterile bandage or negative pressure wound therapy. The negative pressure wound therapy device (PREVENA; Acelity, San Antonio, Texas) was set to 125 mm Hg of continuous negative pressure and remained in place until the first postoperative visit, which occurred approximately 1 week after discharge. Negative pressure wound therapy was removed and replaced, and the wound was left uncovered for the remainder of the recovery period. The senior author began using negative pressure wound therapy for most patients in August 2016. No formal selection criteria were used to determine which patients received negative pressure wound therapy instead of sterile bandage. Patients who received negative pressure wound therapy were subjectively determined to be at an increased risk for infection based on several factors, such as increased body mass index, smoking status, history of infection, and numerous comorbidities.

Operative reports for all patients were reviewed for complications that occurred between the date of initial arthroplasty and the time of chart review. A complication was defined as any adverse event that required return to the operating room for the operative extremity. The type of complication, revision procedure performed, and time between primary arthroplasty and complication correction were recorded. Complications were classified as (1) arthrofibrosis, (2) infection, (3) dehiscence, (4) aseptic failure, (5) fracture, and (6) complex regional pain syndrome.

Patients receiving the standard sterile dressing were compared with those receiving negative pressure wound therapy. Fisher's exact test and the chi-square test were used to evaluate categorical variables, and the t test and Wilcoxon rank sum test were used for continuous variables.

Results

The mean age of patients who received negative pressure wound therapy was 63.4±10.9 years (Table 1), which was significantly older than that of the cohort who received a dry sterile dressing (59.5±9.8 years; P=.0482). Of the 32 patients who had negative pressure wound therapy, 20 patients (62.5%) underwent a TKA and 12 patients (37.5%) underwent a UKA or UniPat. The dry sterile dressing group consisted of 130 TKAs among the 159 total patients (81.8%), which did not differ significantly from the negative pressure wound therapy cohort (P=.0531).

Comparison of Dry Sterile Dressing and Negative Pressure Wound Therapy Cohorts

Table 1:

Comparison of Dry Sterile Dressing and Negative Pressure Wound Therapy Cohorts

Of the 191 total patients undergoing knee arthroplasty, 39 patients (20.4%) had complications requiring return to the operating room (Table 2). Two complications (6.3%) were observed in the negative pressure wound therapy group, which was significantly fewer than the 37 complications (23.3%) in the dry sterile dressing group (P=.0293). Both of these complications in the negative pressure wound therapy group were arthrofibrosis, following a TKA and a UKA, that required a subsequent soft tissue release. The complications in the dry sterile dressing group included 17 instances of arthrofibrosis (10.7%), 9 infections (5.7%), and 7 aseptic failures (4.4%), which were greater than those in the negative pressure wound therapy group but did not reach statistical significance (P=.7455, .3607, and .6035, respectively). Other complications seen in the dry sterile dressing group included 2 periprosthetic fractures, 1 wound dehiscence, and 1 complex regional pain syndrome that returned to the operating room for a nerve block.

Comparison of Complications Between Dry Sterile Dressing and Negative Pressure Wound Therapy Cohorts

Table 2:

Comparison of Complications Between Dry Sterile Dressing and Negative Pressure Wound Therapy Cohorts

Discussion

Complications Following Knee Arthroplasty

Infection following TKA has been estimated to occur in 1% to 2% of patients.10,11 Patel et al12 noted that prolonged wound drainage was associated with significantly longer hospitalizations (P<.001) and increased risk of wound infection. Given that negative pressure wound therapy has been associated with resolution of incisional drainage following arthroplasty,13 anecdotal reasoning would suggest that the application of negative pressure wound therapy would decrease the rate of postoperative complications, including infection.

This study reported a higher rate of postoperative infection (4.7%) compared with much of the literature.10,11 This was partially attributed to the demographic of many patients at the authors' hospital (ie, low socioeconomic status and discharge to skilled nursing facility). These patients may lack compliance with home wound care once leaving the hospital. As a result, the senior author began prophylactic application of negative pressure wound therapy after most knee arthroplasties. Since the initiation of this new wound care protocol, the authors have not recorded a single postoperative infection despite the older population observed in the negative pressure wound therapy group vs the dry sterile dressing group (mean, 63.4 and 59.5 years, respectively; P=.0482). These findings suggest that negative pressure wound therapy may be effective in decreasing the rate of postoperative infection; however, only short-term results are currently available.

Decreasing the rate of infection was the authors' main impetus for applying negative pressure wound therapy to knee arthroplasties. However, they also observed that the rate of return to the operating room for arthrofibrosis was lower, but not statistically significant, in the negative pressure wound therapy group compared with the dry sterile dressing group (6.3% vs 10.7%; P=.7455). Additionally, they noted more complications in the dry sterile dressing group, such as aseptic loosening and fracture. However, these discrepancies were likely not related to the presence of negative pressure wound therapy because there is no clear mechanism by which negative pressure wound therapy would prevent these complications.

Study Limitations

The most significant limitation of this study was that it was retrospective, lacking prospective results. Although most of the severe complications, such as joint infections, would be recorded as a return to the operating room, many of the lesser complications that did not require operative intervention, such as the presence of skin blistering, would not have been observed in this analysis. Another drawback was that comorbid conditions, such as diabetes, high body mass index, smoking, and immunosuppression, that contribute to postoperative complications were not assessed, leaving the possibility of an un-diagnosed confounder. Furthermore, this study did not take into account patient satisfaction. Some patients may be troubled by the presence of bulkier negative pressure wound therapy compared with a smaller dry dressing. Finally, the negative pressure wound therapy group was relatively small (N=32), and these patients' mid- or long-term outcomes were not included because negative pressure wound therapy after knee arthroplasty had only recently been applied. Given that many of the patients in the dry sterile dressing group underwent surgery at an earlier date, they may have had a higher rate of complications because of longer follow-up than the negative pressure wound therapy group.

Other Studies Investigating Negative Pressure Wound Therapy in Knee Arthroplasty

The results of this study add to the growing body of literature regarding the use of negative pressure wound therapy in joint arthroplasty. Cooper and Bas7 performed a retrospective analysis of 138 consecutive revision hip and knee arthroplasties, which included 30 patients who received negative pressure wound therapy. They found that negative pressure wound therapy was associated with significantly fewer wound complications (P=.024) and superficial skin infections (P=.045). Additionally, negative pressure wound therapy resulted in fewer prosthetic joint infections and fewer reoperations when compared with antimicrobial dressings; however, these findings were not statistically significant.

Manoharan et al9 prospectively assessed the outcomes of 21 patients undergoing bilateral TKA with each side randomized to receive either a dry dressing or negative pressure wound therapy. The knees covered with negative pressure wound therapy had decreased wound leakage and better surgical site protection in the first 7 days postoperatively. However, the authors also noted that negative pressure wound therapy resulted in an increased cost compared with dry dressings (396.02 vs 43.51 Australian dollars).

When evaluating the role of negative pressure wound therapy in the resolution of wound drainage after TKA, Howell et al8 reported skin blistering in 15 (63%) of the 24 knees that received negative pressure wound therapy, which was significantly greater than the sterile gauze group (12%). They speculated that the blisters resulted from skin friction during knee range of motion at the transition point from the foam to adhesive tape. Their reported rate of blistering (63%) differed greatly from that of Manoharan et al9 (5%), which may be due to a confounding factor such as differences between the facilities in the protocols for postoperative range of motion rehabilitation.

Conclusion

There was a significantly greater number of overall complications in the dry sterile dressing group compared with the negative pressure wound therapy group, although several of these complications, such fracture and aseptic failure, were likely unrelated to the presence of negative pressure wound therapy. A lower infection rate was observed for the negative pressure wound therapy patients as opposed to the dry sterile dressing patients, although this difference was not statistically significant. This study contributes to the literature regarding negative pressure wound therapy for arthroplasty patients. However, the lack of large prospective trials has limited orthopedic surgeons from reaching definitive conclusions about the benefits of negative pressure wound therapy for patients postoperatively.

References

  1. Argenta LC, Morykwas MJ. Vacuum-assisted closure: a new method for wound control and treatment. Clinical experience. Ann Plast Surg. 1997;38(6):563–576. doi:10.1097/00000637-199706000-00002 [CrossRef]
  2. Morykwas MJ, Argenta LC, Shelton-Brown EI, McGuirt W. Vacuum-assisted closure: a new method for wound control and treatment. Animal studies and basic foundation. Ann Plast Surg. 1997;38(6):553–562. doi:10.1097/00000637-199706000-00001 [CrossRef]
  3. Stannard JP, Volgas DA, Stewart R, McGwin G Jr, Alonso JE. Negative pressure wound therapy after severe open fractures: a prospective randomized study. J Orthop Trauma. 2009;23(8):552–557. doi:10.1097/BOT.0b013e3181a2e2b6 [CrossRef]
  4. Kelm J, Schmitt E, Anagnostakos K. Vacuum-assisted closure in the treatment of early hip joint infections. Int J Med Sci. 2009;6(5):241–246. doi:10.7150/ijms.6.241 [CrossRef]
  5. Kirr R, Wiberg J, Hertlein H. Clinical experience and results of using the V.A.C. instill therapy in infected hip and knee prosthetics [in German]. Zentralbl Chir. 2006;131(suppl 1):S79–S82. doi:10.1055/s-2005-921501 [CrossRef]
  6. Lehner B, Bernd L. V.A.C.-instill therapy in periprosthetic infection of hip and knee arthroplasty [in German]. Zentralbl Chir. 2006;131(suppl 1):S160–S164. doi:10.1055/s-2006-921513 [CrossRef]
  7. Cooper HJ, Bas MA. Closed-incision negative-pressure therapy versus antimicrobial dressings after revision hip and knee surgery: a comparative study. J Arthroplasty. 2016;31(5):1047–1052. doi:10.1016/j.arth.2015.11.010 [CrossRef]
  8. Howell RD, Hadley S, Strauss E, Pelham FR. Blister formation with negative pressure dressings after total knee arthroplasty. Curr Orthop Pract. 2011;22:176–179. doi:10.1097/BCO.0b013e31820b3e21 [CrossRef]
  9. Manoharan V, Grant AL, Harris AC, Hazratwala K, Wilkinson MP, McEwen PJ. Closed incision negative pressure wound therapy vs conventional dry dressings after primary knee arthroplasty: a randomized controlled study. J Arthroplasty. 2016;31(11):2487–2494. doi:10.1016/j.arth.2016.04.016 [CrossRef]
  10. Hanssen AD, Rand JA. Evaluation and treatment of infection at the site of a total hip or knee arthroplasty. Instr Course Lect. 1999;48:111–122.
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  12. Patel VP, Walsh M, Sehgal B, Preston C, De-Wal H, Di Cesare PE. Factors associated with prolonged wound drainage after primary total hip and knee arthroplasty. J Bone Joint Surg Am. 2007;89(1):33–38. doi:10.2106/JBJS.F.00163 [CrossRef]
  13. Hansen E, Durinka JB, Costanzo JA, Austin MS, Deirmengian GK. Negative pressure wound therapy is associated with resolution of incisional drainage in most wounds after hip arthroplasty. Clin Orthop Relat Res. 2013;471(10):3230–3236. doi:10.1007/s11999-013-2937-3 [CrossRef]

Comparison of Dry Sterile Dressing and Negative Pressure Wound Therapy Cohorts

CharacteristicCohortP

Total (N=191)DSD (N=159)NPWT (N=32)
Age, y
  Mean (SD)60.2 (10.1)59.5 (9.8)63.4 (10.9).0482
  Median (range)58.6 (35.7–85.5)58.0 (35.7–82.3)60.6 (42.1–85.5)
Procedure type, No.
  TKA150 (78.5%)130 (81.8%)20 (62.5%).0531
  UKA27 (14.1%)19 (11.9%)8 (25.0%)
  UniPat14 (7.3%)10 (6.3%)4 (12.5%)

Comparison of Complications Between Dry Sterile Dressing and Negative Pressure Wound Therapy Cohorts

ComplicationCohortP

Total (N=191)DSD (N=159)NPWT (N=32)
Any, No.39 (20.4%)37 (23.3%)2 (6.3%).0293
  Arthrofibrosis19 (9.9%)17 (10.7%)2 (6.3%).7455
  Aseptic failure7 (3.7%)7 (4.4%)0 (0%).6035
  Dehiscence1 (0.5%)1 (0.6%)0 (0%)
  Fracture2 (1.0%)2 (1.3%)0 (0%)
  Infection9 (4.7%)9 (5.7%)0 (0%).3607
  CRPS1 (0.5%)1 (0.6%)0 (0%)
Additional surgery, No.
  0 (no complication)152 (79.6%)122 (76.7%)30 (93.8%)
  1 complication31 (16.2%)29 (18.2%)2 (6.3%)
  2 complications4 (2.1%)4 (2.5%)0 (0%)
  3+ complications4 (2.1%)4 (2.5%)0 (0%)
By procedure, No/Total No.
  TKA34/150 (22.7%)33/130 (25.4%)1/20 (5.0%).0460
  UKA5/27 (18.5%)4/19 (21.1%)1/8 (12.5%)1.0000
  UniPat0/14 (0%)0/10 (0%)0/4 (0%)
Authors

The authors are from the Department of Orthopedics (AJC, ATV), Medstar Georgetown University Hospital, Georgetown University School of Medicine (EBT), and the Department of Orthopedics (EHA), Medstar Washington Hospital Center, Washington, DC.

Dr Curley, Ms Terhune, and Dr Velott have no relevant financial relationships to disclose. Dr Argintar is a paid consultant for Acelity and Trice.

Assistance with statistical analysis was provided by Acelity.

Correspondence should be addressed to: Andrew J. Curley, MD, Department of Orthopedics, Medstar Georgetown University Hospital, 3800 Reservoir Rd, Washington, DC 20007 ( AndrewJCurley@gmail.com).

Received: February 18, 2018
Accepted: June 26, 2018
Posted Online: October 16, 2018

10.3928/01477447-20181010-02

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