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LETTER TO THE EDITOR

Do Continuous Femoral Nerve Blocks Affect the Hospital Length of Stay and Functional Outcome?

Department of Anesthesiology; Orthopaedic Anesthesia and Acute Interventional Perioperative Pain Divisions; University of Pittsburgh Medical Center; UPMC Presbyterian-Shadyside Hospital; Pittsburgh, PA; chelje{at}anes.upmc.edu

To the Editor:

Salinas et al. (1) demonstrated analgesic benefits associated with the use of continuous femoral nerve blocks compared to single femoral blocks for total knee replacement, similar to prior results from our group (2). However, they questioned the value of continuous blocks because there was no benefit in length of stay or the degree of flexion of the knee at 6 and 12 wk.

This outcome was a fait accompli of the study design, and does not reflect the improvement patients experience from a continuous technique. Specifically,

1. The surgeon and the principal physical therapist deciding the appropriate discharge time based on subjective criteria (Table 1) (1).
   
2. The physical therapy program was limited to two sessions per day. It is unclear if patients were allowed to have physical therapy sessions on the day of surgery. Patients with continuous blocks better tolerated physical therapy sessions and therefore may have benefited from a more "aggressive" program, a key element of accelerated functional recovery (3). In our institution, we offer up to three physical therapy sessions starting on the day of surgery, and some of our patients undergoing total joint replacement go home on the same day of surgery.
   
3. Outcome only considered the degree of knee flexion, and not the overall functional recovery as assessed by the SF36 (4).
   
4. No attention was given to the physical therapy program after patient discharge.
   

The authors considered a length of stay <3.7 days improbable, based on data published in a knee registry developed with surgeons performing an average of <10 joint replacements per year. Many orthopaedic surgeons performing a large number of total knee replacements report length of stays <3.7 days and in many cases of 23 h or less (5–7).

Early functional recovery after joint replacement depends upon the surgical technique (traditional versus minimally invasive), the intensity of the physical therapy program (3), the preoperative condition of the patient (5), and the anesthesia and postoperative pain management techniques (8,9). The use of regional anesthesia is an important component of optimum functional recovery (10). Length of stay is also dependent upon reimbursement (in some states the hospital reimbursement is prorated up to 4 or 5 days) and pre-established pathways (surgeon and staff behaviors are very difficult to change). In conclusion, the study was not designed to allow any conclusion on the effects of continuous versus single femoral nerve blocks on length of stay and patient outcome.

REFERENCES

1. Salinas FV, Liu SS, Mulroy MF. The effect of single-injection femoral nerve block versus continuous femoral nerve block after total knee arthroplasty on hospital length of stay and long-term functional recovery within an established clinical pathway. Anesth Analg 2006;102:1234–9.[Abstract/Free Full Text]
2. Chelly JE, Greger J, Gebhard R, et al. Continuous femoral blocks improve recovery and outcome of patients undergoing total knee arthroplasty. J Arthroplasty 2001;16:436–46.[Web of Science][Medline]
3. Munin MC, Rudy TE, Glynn NW, et al. Early inpatient rehabilitation after elective hip and knee arthroplasty. JAMA 1998;18279:847–52.
4. Ware JF. SF-36 Health survey: manual and interpretation guide. Boston: The Health Institute, New England Medical Center, 1993:3:1–3:9.
5. Berger RA, Sanders S, D'Ambrogio E, et al. Minimally invasive quadriceps-sparing TKA: results of a comprehensive pathway for outpatient TKA. J Knee Surg 2006;19: 145–8.[Medline]
6. Alan RK, Tria AJ Jr. Quadriceps-sparing total knee arthroplasty using the posterior stabilized TKA design. J Knee Surg 2006;19:71–6.[Medline]
7. Ilfeld BM, Gearen PF, Enneking KF, et al. Total knee arthroplasty as an overnight-stay procedure using continuous femoral nerve blocks at home: a prospective feasibility study. Anesth Analg 2006;102: 87–90.[Abstract/Free Full Text]
8. Mears DC. Development of a two-incision minimally invasive total hip replacement. J Bone Joint Surg Am 2003; 85A:2238.
9. Hirst GC, Lang SA, Dust WN, et al. Femoral nerve block: single injection versus continuous infusion for total knee arthroplasty. Reg Anesth 1996;21:292–7.[Web of Science][Medline]
10. Buvanendran A, Tuman KJ, McCoy DD, et al. Anesthetic techniques for minimally invasive total knee arthroplasty. J Knee Surg 2006;19:133–6.[Medline]

This article has been cited by other articles:

				F. V. Salinas Do Continuous Femoral Nerve Blocks Affect the Hospital Length of Stay and Functional Outcome? Anesth. Analg., April 1, 2007; 104(4): 997 - 998. [Full Text] [PDF]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Chelly, J. E. Articles by Ben-David, B. Search for Related Content PubMed PubMed Citation Articles by Chelly, J. E. Articles by Ben-David, B.