Prognostic Factors for Repeated Flexor Tenosynovitis Washout: A Retrospective Study

Flexor tenosynovitis is a potentially devastating infection of the flexor tendon synovial sheath, which can lead to significant morbidity if not adequately treated. Despite no standardized algorithm for its management, most patients undergo surgical washout along with administration of intravenous antibiotics. However there is significant heterogeneity among surgical techniques reported, including the type of incision, washout solution, duration of washout, and postoperative care.[1] We conducted an audit to identify operative and nonoperative factors that contribute to higher rates of repeated flexor tendon washouts.

A retrospective audit was performed using patient notes of 101 flexor tendon washouts conducted over a 4-year period (2015–2018) at a central London teaching hospital. Patients with iatrogenic etiology were excluded. Dependent variables included patient age and gender, smoking status, injury mechanism, wound culture, incision type (open Brunner type vs. catheter irrigation methods), presence of pus during procedure, washout solution used, and closure method. The primary outcome was requirement for repeated flexor tendon washout. Multiple logistic regression analysis was performed using the MedCalc software, with p-value of < 0.05 considered as statistically significant.[2]

The average number of surgical washouts for flexor tenosynovitis was 1.5, with 58.4% of patients only requiring one procedure. All patients were prescribed intravenous antibiotics on admission, and all patients had at least one swab taken from the flexor sheath during the primary operation. Men were more likely to present (62.2% total presentations), with the average age 42.3 years ([Table 1]). The most common identified mechanism of injury was penetrating injury (28.7%), of which four cases had an identifiable foreign body removed during primary washout procedure. This was followed by animal bite (11.9%), preexisting inflammation/infection (e.g., gout, paronychia [8.9%]), human bite (3.0%), and insect bite (2.0%). The remaining patients (45.6%) were unable to recall any inciting event prior to developing infection. There was no association observed between mechanism and reoperation (p = 0.24).

Table 1 Demographic data and operative variables

Demographic data
Average age (y)		42.3 (6–76)
Male:Female		63:38
Smoker		45.0%
Mechanism	Penetrating injury	28.7%
	Animal bite	11.9%
	Preexisting infection/inflammation	8.9%
	Human bite	3.0%
	Insect bite	2.0%
	Unknown	45.5%
Operative variables
Positive wound culture		36.6%
Pus identified in flexor sheath		49.5%
Open irrigation		56.4%
Irrigation solution	Saline irrigation only	72.3%
	Saline + betadine	4.0%
	Saline + hydrogen peroxide	22.8%
Closure with tacking sutures		56.4%

Open drainage was more often performed compared with catheter irrigation (56.4% vs. 43.6%, respectively), with 72.3% of cases irrigated with saline only. No patients underwent postoperative catheter irrigation. Just under half of cases were left open for drainage following irrigation (43.6%), with the remainder partially closed using tacking sutures. Only the presence of pus was found to significantly influence the likelihood of requiring further washouts (odds ratio [OR]: 6.35, confidence interval: 2.34–17.17, p < 0.001). There was no significant association between pus and positive wound culture (OR: 2.12, p = 0.126), with Staphylococcus aureus the most frequently cultured microorganism (17.8%) ([Table 1]).

Our audit identified pus as the only significant predictive factor for repeated flexor tendon washout. This may reflect more severe and deep-seated infection, or may act as a visual prompt which can bias future clinical assessment in favor of relook procedures. Concordant with the latter hypothesis, our results demonstrated no significant association between pus and positive wound culture, although this may also reflect a high degree of type II error from swab contamination.

We found no significant association between irrigation method (open vs. catheter) and reoperation rates, consistent with previous studies.[3] This may suggest both techniques are adequate for removal of infectious material if performed thoroughly. While there were observed differences in irrigation solutions used (saline vs. saline and betadine/hydrogen peroxide), this did not appear to affect requirement for reoperation. Indeed, the primary purpose of irrigation is to remove infectious material, and it is unlikely the antiseptic solution would persist long enough to have any meaningful effect on resident bacteria. This is corroborated by the lack of supporting evidence for the use of antibiotics within the irrigation solution.[4]

While these results suggest that multiple different operative strategies are adequate for surgical debridement in flexor tenosynovitis, they do not give insight into longer term functional outcomes. Indeed, previous reports have shown catheter irrigation methods to result in greater range of motion compared with open washout, and may therefore represent a more appropriate primary modality.[4] [5] Similarly, although we found no associations between smoking status or swab culture results and reoperation rates, both parameters have be shown to negatively affect longer term outcomes.[3]

A limitation of this study is potential confounding from unreported variables including latent period from injury to surgery along with medical comorbidities, both of which have been shown to affect functional outcomes.[4] [5] Nevertheless, given that our primary outcome of interest was the requirement for further washout, which is more likely to reflect the adequacy of primary operation, we feel the conclusions remain valid.

In summary, we suggest that the presence of pus within the flexor sheath should alert the surgeon to higher risk of repeated flexor sheath washout. We therefore suggest this finding should prompt more intensive surgical washout, along with diligent postoperative follow-up on the ward.

Publication History

Article published online:
09 September 2020

• References

• 1 Chapman T, Ilyas AM. Pyogenic flexor tenosynovitis: evaluation and treatment strategies. J Hand Surg Am 2019; 44 (11) 981-985
• 2 MedCalc statistical software. Accessed December 9, 2019 at: https://www.medcalc.org/
• 3 Born TR, Wagner ER, Kakar S. Comparison of open drainage versus closed catheter irrigation for treatment of suppurative flexor tenosynovitis. Hand (N Y) 2017; 12 (06) 579-584
• 4 Giladi AM, Malay S, Chung KC. A systematic review of the management of acute pyogenic flexor tenosynovitis. J Hand Surg Eur Vol 2015; 40 (07) 720-728
• 5 Dailiana ZH, Rigopoulos N, Varitimidis S, Hantes M, Bargiotas K, Malizos KN. Purulent flexor tenosynovitis: factors influencing the functional outcome. J Hand Surg Eur Vol 2008; 33 (03) 280-285