Infected Total Knee Arthroplasty; Two-stage Reimplantation With a Gastrocnemius Rotational Flap

What Factors Influence the Success of Medial Gastrocnemius Flaps in the Treatment of Infected TKAs?

“…The observed high frequency of recurrent or persistent periprosthetic joint infection and low frequency of prosthetic retention compare poorly with results of two prior studies that examined the outcomes of gastrocnemius muscle flap reconstruction for infected TKAs [6,19] ( Table 4). The poorer results in our cohort may be partly attributable to a greater number of knee operations before flap coverage and/or greater soft tissue loss.…”

“…There was a trend toward failure when flap coverage was performed at the same time as antibiotic spacer placement but this did not reach statistical significance. Although acceptable results have been reported with performance of the gastrocnemius flap at first-stage resection TKA [6] and at second-stage reimplantation [19], our findings suggest that in the setting of two-stage exchange arthroplasty, delaying flap coverage until after treatment of infection may be advisable if the soft tissue is amenable to closure at the time of resection or spacer exchange. Alternatively, it is plausible that patients who underwent flap coverage with spacer placement had more severe soft tissue defects, which contributed to poorer outcomes.…”

“…There also presumably was overlap in patient populations between the two studies by Ries [27] and Ries and Bozic [28]. [6] reported that 42% of their flaps followed a primary TKA versus only 7% in our cohort, while McPherson et al [19] reported a mean of 3.4 (range, 1-6 operations) prior knee procedures compared with four (range, 1-11 operations) in our cohort, seemingly a lesser difference. Meanwhile, neither study reported a measure of soft tissue loss at the time of flap coverage; it is plausible that the substantial soft tissue loss (average defect area of 20 cm 2 ) in our study group contributed to comparatively poorer outcomes.…”

“…Although some authors [8,19,20,31] have proposed poor prognostic factors based on smaller series, our study is the first, to our knowledge, to statistically evaluate factors associated with flap failure in this setting. There was a trend toward failure when flap coverage was performed at the same time as antibiotic spacer placement but this did not reach statistical significance.…”

“…The fact that all flaps reliably healed suggests that subsequent poor function may be tied to the severity of soft tissue compromise and underlying prosthetic infection rather than flap choice or technique. It is possible that earlier ROM of the knee after flap coverage may have improved functional outcomes, however, investigators who reported ranging the knee as early as 10 days also reported a higher rate of wound complications [19]. Although sensation in the flap is poor, the functional loss and comorbidity associated with the flap is generally minimal because of compensation provided by the remaining soleus and hemigastrocnemius muscle [11,18].…”