| Hot Topics in Joint Preservation and Joint Arthroplasty (H)- Index

Diagnosis and Treatment of Acute Post-Operative Infections Following Primary Total Knee Arthroplasty

Craig J. Della Valle, MD

Introduction

Infection is among the most feared complications following primary total knee arthroplasty (TKA). Diagnosis can be extremely difficult in the early post-operative period secondary to normal post-operative pain, edema and peri-incisional erythema that make the appearance of the wound and normal cues to diagnosis extremely difficult.

Treatment is equally difficult as there is a paucity of literature on the topic, and the reported rates of success are variable without a clear consensus on appropriate treatment.

Diagnosis of Infection in the Early Post-Operative Period

While the ESR and CRP have been found to be useful in the diagnosis of chronic periprosthetic joint infection, there is minimal data on their utility in the early post- operative period where one would expect they would be elevated and thus traditional cut- off values (30mm/hr for the ESR and 10-15mg/L for the CRP).

Similarly, while the synovial fluid WBC count has been shown to be useful for the diagnosis of chronic PJI in several studies, there is only recent literature on the utility of this test within the first few weeks where large amounts of blood would be expected to be around the hip joint and some inflammation would be expected.

Retrospective review of 11,964 primary TKA at (2) centers (Jefferson, Rush)


Mean Values for Patients with and without Acute Post-Operative Infection

Infected (N=19) Not Infected (N=127) P-V alue
ESR (mm/hr) 80 (38-140) 75 (1-140) 0.46
CRP (mg.L) 171 (29-490) 88 (4-382) 0.004
Synovial Fluid WBC Count (per uL) 92,600
(3,520-570,000)
4,200 (0-41,000) < 0.001
Differential (% PMN) 90% (6-99) 77% (5-100) 0.0341

ESR: Not found to be helpful

CRP: Helpful! Optimal threshold (balance sensitivity/specificity) 95 mg/L (nl 8 mg/L)

Synovial Fluid WBC Count: Helpful! In fact the most helpful test!

Differential (%PMN): Helpful!

Bottom Line: If you are unsure if you should aspirate, get a CRP; if >100 mg/L aspirate!

We have similar date for hips too! As of yet unpublished...

Treatment of Infection in the Early Post-Operative Period

Not a lot of literature to look to for guidance; most series are small, all are retrospective and the endpoints are variable and success is not uniformly defined. Most common treatment is an irrigation and debridement with exchange of the modular bearing surface (if present). Many have recently questioned the value of this intervention.

Irrigation and Debridement

Perform a full synovectomy and bearing surface exchange if possible (allows for better exposure particularly posteriorly) followed by six weeks of IV antibiotics (although again little data to support this precise time period of treatment) followed by a variable course of oral antibiotics ranging from no oral antibiotic treatment to lifelong suppression. Most studies suggest a success rate of ~50%

One Stage Exchange: More recent interest in exploring this technique.

Two-Stage Exchange: A “conservative” option?

Bottom Line: I+D is still what I do as my first option, however...


References

1. Bedair H, Ting N, Moric M, Saxena A, Jacovides C, Parvizi J, Della Valle CJ. Diagnosis of infection in the early post-operative period following primary total knee arthroplasty: Clin Orthop Relat Res. 2011 Jan;469(1):34-40.

2. Bradbury T, Fehring TK, Taunton M, et. al. The fate of acute methicillin-resistant staphylococcus aureus periprosthetic knee infections treated with open debridement. J Arthroplasty. 2009 Sep;24(6 Suppl):101-4.

3. Deirmengian C, Greenbaum J, Stern J, Braffman M, Lotke PA, Booth RE Jr, Lonner JH. Open debridement of acute gram positive infections after total knee arthroplasty. Clin Orthop Relat Res. 2003 Nov;(416):129-34.

4. Della Valle C, Parvizi J, Bauer TW, et al. AAOS clinical practice guideline on the diagnosis of PJI. J Bone Joint Surg Am. 2011 Jul 20;93(14):1355-7.

5. Della Valle CJ, Sporer SM, Jacobs JJ, et. al. Perioperative testing for sepis prior to revision total knee arthroplasty. J Arthroplasty. 22: suppl 2, 90-93, 2007.

6. Sherrell JC, Fehring TK, Periprosthetic Infection Consortium. Fate of 2-Stage Exchange after Failed Debridement for Periprosthetic Knee Infection. Clin Orthop Relat Res. 2011 Jan;469(1):18-25.

7. Odum SM, Fehring TK, Periprosthetic Infection Consortium.Irrigation and Debridement for Periprosthetic Joint Infection. Does the Organism Matter? J Arthroplasty. 2011 Sep;26(6 Suppl):114-8.