Abstract
Background:
The long-term outcomes of femoral nerve blockade following ACL reconstruction are not well defined. Femoral nerve blocks are typically administered as either a single-injection nerve block (FNB) or a continuous femoral nerve catheter (FNC). Prior work among pediatric patients found knee extension and flexion strength deficits 6 months postoperatively using FNB. However, this work was limited by the use of multiple graft choices and orthopedic surgeons.
Purpose/Hypothesis:
The purpose of this study was to investigate functional recovery after primary ACL surgery with quadriceps tendon-patellar autograft (QPA) in patients receiving a sciatic nerve block and either FNB or FNC. Our hypothesis was that short-term functional performance would be worse among those who underwent FNC compared to FNB.
Methods:
We conducted a retrospective chart review of pediatric patients 10-19 years of age who underwent ACL reconstruction with QPA by a single orthopedic surgeon. Surgery was performed at two locations: one of which administered FNB and the other FNC. Both were combined with sciatic nerve block. A physical therapist performed functional asymmetry assessments at approximately 6 months postoperative. We compared single-leg squat symmetry between groups using independent samples t-tests. We compared the proportion of patients in each group who achieved 80% symmetry on single-leg squat and Y-Balance tests, had initiated ballistics and running programs, and demonstrated functional symmetry at the 6-month post-operative appointment using Chi-square analyses.
Results:
Demographics were similar between groups (Table 1). Single leg percent symmetry of the operative limb was significantly greater in the FNB group compared to the FNC group (Table 2). In addition, a greater proportion of those in the FNB group demonstrated functional symmetry compared to the FNC group during the 6-month assessment (Table 2). There were no proportional differences between the groups for the number of patients who demonstrated 80% symmetry during single-leg squat or Y-Balance test, or had initiated a ballistics or running program at the time of assessment.
Conclusion:
Pediatric patients in the FNC group demonstrated poorer single-leg squat symmetry and functional symmetry compared to those in the FNB group at 7 months following ACL reconstruction with QPA. These preliminary findings may relate to increased concentration and duration of local anesthetic in the FNC group postoperatively. Providers should be cognizant of the implications of FNC on long-term outcomes of ACL reconstruction.
Patient demographic and surgery characteristics between those who received a femoral nerve catheter compared to those who received a femoral nerve block single shot.
| Variable | Femoral nerve single shot block |
Femoral nerve catheter |
P value |
|---|---|---|---|
| Female sex | 30 (53%) | 16 (52%) | 0.93 |
| Age (years) | 15.6 (1.8) | 15.6 (1.7) | 0.88 |
| Height (cm) | 167.4 (9.5) | 164.8 (18.2) | 0.48 |
| Weight (kg) | 66.5 (11.5) | 67.2 (20.1) | 0.87 |
| Tourniquet time (minutes) | 90.3 (22.7) | 93.7 (15.2) | 0.43 |
| Concomitant meniscus injury | 20 (65%) | 31 (54%) | 0.36 |
| Non-contact mechanism of injury | 20 (65%) | 38 (57%) | 0.91 |
| Time of follow-up assessment (months post-surgery) | 6.1 (0.6) | 6.1 (0.5) | 0.82 |
Functional outcomes at the follow-up assessment. Data are presented as the number in each group / total number of patients who had data for that variable (corresponding percentage), or as mean (sd).
| Variable | Femoral nerve single shot block | Femoral nerve catheter | P value |
|---|---|---|---|
| Achieved 80% symmetry on the single-leg squat | 15/18 (83%) | 16/27 (59%) | 0.09 |
| Single-leg squat symmetry | 95.5 (6.7) | 88.3 (9.3) | 0.02* |
| Initiated ballistics at follow-up assessment time | 28/31 (90%) | 43/56 (77%) | 0.12 |
| Initiated running program at follow-up assessment time | 17/25 (68%) | 38/56 (68%) | 0.99 |
| Achieved 80% symmetry on the Y-Balance test | 10/10 (100%) | 15/18 (83%) | 0.17 |
| Demonstrated functional symmetry at follow-up assessment | 7/19 (37%) | 2/24 (8%) | 0.02* |