Risk of Falling after Femoral Nerve Block for Total Knee Arthroplasty: Periprosthetic Fractures A Serious Concern

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1 jorapain Original Article Risk of Falling after Femoral Nerve /jp-journals Block for Total Knee Arthroplasty Risk of Falling after Femoral Nerve Block for Total Knee Arthroplasty: Periprosthetic Fractures A Serious Concern 1 Vikram I Shah, 2 Sachin Upadhyay, 3 Kalpesh Shah, 4 Ashish N Sheth, 5 Amish Kshatriya, 6 Anivesh Jain 7 Pankaj Sharma, 8 Jatin G Sanandia ABSTRACT Objective: Femoral nerve block (FNB) is a popular, minimally invasive postoperative pain management procedure following total knee arthroplasty (TKA). Prolonged motor blockade has been associated with increased risk of fall. The primary objective of the present study was therefore, to evaluate the risk of falling or near falling for FNB in patients who underwent TKA. Materials and methods: After Institutional Review Board approval, prospective cohort (142) of patients was randomized into two groups: the intervention (FNB as an adjunct to analgesia) vs the control (standard treatment) at our hospital for unilateral primary conventional TKA. The risk of falling as assessed using Tinetti Gait and Balance Instrument and Timed Up and Go (TUG) test was evaluated on the day of hospital discharge, and 1, 2, and 3 months after TKA. All data were collected and critically analyzed and p < 0.05 was considered statistically significant. Results: Patients in FNB group displayed significant low visual analog scale (VAS) scores than control (p < 0.05). Thirty-seven patients (26.05%) reported falls in the 3 months after surgery. Patients who received FNB following TKA experienced an expected significant worsening of physical function and had increased risk of falling as evaluated by TUG test and Tinetti Gait and Balance Instrument (p < 0.05). Due to unexpected fall, eight patients (28.57%) in FNB group sustained periprosthetic fractures and two patients (22.2%) in control group had opening of arthrotomy. At 3 months, 55 patients in FNB group had reported postoperative neuritis. Significant delay in rehabilitation and early ambulation in patients received FNB, which in turn increases the risk of prolonged hospitalization (p < 0.05). 1 Chairman and Managing Director, 2,6,7 Consultant, 3-5,8 Senior Surgeon 1,3-5 Department of Knee and Hip Replacement, Shalby Hospitals Ahmedabad, Gujarat, India 2 Department of Trauma, Joint Replacement and Minimal Invasive Surgery Hospitals Jabalpur, Madhya Pradesh, India 6,7 Department of Anesthesia and Critical Care, Shalby Hospitals Jabalpur, Madhya Pradesh, India 8 Department of Trauma, Shalby Hospitals, Ahmedabad, Gujarat India Corresponding Author: Sachin Upadhyay, Consultant Department of Trauma, Joint Replacement and Minimal Invasive Surgery Hospitals Jabalpur, Madhya Pradesh, India, Phone: , drsachinupadhyay@gmail.com Conclusion: The Tinetti and gait index and TUG test time showed increased risk of fall for the patients who received FNB owing to substantial functional deficits. Keywords: Femoral nerve block, Periprosthetic fractures, Timed Up and Go test, Tinetti and gait index, Total knee arthroplasty. How to cite this article: Shah VI, Upadhyay S, Shah K, Sheth AN, Kshatriya A, Jain A, Sharma P, Sanandia JG. Risk of Falling after Femoral Nerve Block for Total Knee Arthroplasty: Periprosthetic Fractures A Serious Concern. J Recent Adv Pain 2017;3(3): Source of support: Nil Conflict of interest: None INTRODUCTION Total knee arthroplasty is the most acknowledged successful surgical intervention for osteoarthritis that often results in considerable postoperative pain which often hinders physical therapy (PT) and rehabilitation that adversely affects outcome and diminishes functional recovery. Postoperative analgesia is a critical aspect of TKA, as effective and adequate analgesia has been shown to produce high levels of patient satisfaction, improves functional outcomes, shortens hospital length of stay, and lowers costs of care. Several analgesia techniques have been employed to meet multiple, often competing demands, with each presenting specific advantages and drawbacks. Femoral nerve block is an effective and accepted mode of postoperative analgesia for TKA but has a documented complication rate and associated with increased risk of falls due to quadriceps weakness. 1 The primary objective of this prospective, randomized controlled study was therefore, to evaluate the risk of falling or near falling for FNB in patients who underwent TKA. The authors also evaluated pain scores; analgesic consumption during the postoperative days (PODs), and length of hospital stay as their secondary objectives. We hypothesized that group where FNB has been used as postoperative analgesia as an adjunct would have increased risk of fall when compared with the control group. We hypothesized that increased risk of fall would be negatively correlated with rehabilitation process. Journal on Recent Advances in Pain, September-December 2017;3(3):

2 Vikram I Shah et al MATERIALS AND METHODS Study Design The present study was a multicentric, controlled, blinded, randomized, prospective comparative analysis to evaluate the risk of falls of FNB used as an adjunct to multimodal analgesia (treatment group FNB) with control group (control) in patients who underwent primary unilateral total knee replacement (TKR) between August 2016 and February 2017 at our institution. The study was approved by the Scientific Review Committee and the Institutional Review Board of the participating Health Service. Written informed consent (about the surgical technique, risks, and potential complications) was provided according to the Declaration of Helsinki and obtained from all participating patients. Inclusion and Exclusion Criteria The inclusion criteria were as follows: Patients of either sex with grade three or four primary osteoarthritis knees in at least one tibiofemoral compartment (Kellgren and Lawrence system) 2,3 and voluntary participation in the study. Exclusion criteria consisted of (1) active inflammatory or connective tissue disease (i.e., lupus, rheumatoid arthritis), (2) neuropathy, (3) a history of patellar fracture, patellectomy, patellofemoral instability, or prior unicondylar knee replacement or high tibial osteotomy, (4) hypersensitivity to nonsteroidal anti-inflammatory drugs (NSAIDs) or local anesthetic agents, abnormal liver or renal profile, history of peptic ulceration and upper gastrointestinal hemorrhage, cancer, hyperkalemia, (5) history of coagulopathies, hematological or neuromuscular disorders, (6) psychiatric diagnosis and/or any other circumstances that would make participation not in the best interest of the cohort or could prevent the protocolspecified outcome evaluation. Procedure A target population of 142 patients (35 men and 107 women) were enrolled in this multicentric prospective analysis and were randomized into two groups: Those who received a FNB (treatment group; GF, n = 71) and those who did not (control group; GC, n = 71). The patients were examined/screened for their severity of arthritis (Kellgren and Lawrence system) 2,3 and deformity. Clinicodemographic variables, including age, gender, grading of osteoarthritis, deformity, and comorbidity if any were recorded preoperatively (Table 1). All the operations were either performed or supervised by the senior author using standard midline incision with medial parapatellar arthrotomy without tourniquet under spinal anesthesia. Standard cuts and release were made and soft tissue balancing done. Patellar resurfacing was done in all cases. Trial checking was done. All had posterior stabilized metal-backed TKR. All the components were cemented. Wound closure was done in layers after thorough pulse lavage. No drains were used in either group. After completion of closure, under aseptic precautions ultrasound-guided single-injection FNB with 20 ml of 0.5% ropivacaine was administered to the FNB group. 4 Both groups received similar anesthetic procedure, postoperative analgesia, and rehabilitation protocol. All patients received a standardized analgesia regimen during POD 1 4 consisting of diclofenac suppositories 50 mg PR 6 hourly until discharge. No parenteral narcotics were used. Patients who reported moderate-to-severe pain (i.e., if the VAS 3) were given IV 1 gm acetaminophen as rescue medication. Postoperative ankle pumps means ankle movements to be started by patients after the surgery. Static quadriceps and high sitting were allowed from the next morning. Straight-leg raise (SLR) was allowed whenever patient was comfortable. The range of movement was documented daily by a physical therapist using a goniometer. Following discharge, all patients were given a standard discharge analgesic medication and rehabilitation protocol. Data were collected by an assessor who was blind to the patients group allocations for the duration of study. Assessment was performed prior to surgery, on the day of discharge, at 1, 2, and 3 months following surgery. Complications, such as fall or near fall, periprosthetic fractures, neuritis, or any other adverse effects were documented. 126 Table 1: Clinicodemographic variables Characteristics Control FNB group p-value Age (years) ± ± 2.31 p = 0.3 Sex 54 female (76.05%) 17 male (23.94%) Severity of disease (Kellgren and Lawrence system) 55 grade IV (77.46%) 16 grade III (22.53%) 53 female (74.64%) 18 male (25.35%) 54 grade IV (76.05%) 17 grade III (23.94%) χ 2 = 0.03 p = χ 2 = 0.03 p = Deformity (in degree) (varus/valgus) 15.9 ± ± 1.20 p = 0.28 Flexion angle (in degree) ± ± 1.01 p = 0.1 Comorbidity (HTN, IHD) 53.52% (n = 38) % (n = 39) χ 2 = p = HTN: Hypertension; IHD: Ischemic heart disease

3 jorapain Risk of Falling after Femoral Nerve Block for Total Knee Arthroplasty Table 2: Visual analog scale Tool Preoperative (Baseline) POD (1 4)/at discharge 1 month 2 months 3 months Control VAS 6.89 ± ± ± ± ± 1.18 t-value p-values < < < FNB 6.76 ± ± ± 1.02* 3.99 ± 1.33* 3.5 ± 1.20* t-value p-value < < < < *Eight patients were excluded (n = 63) Table 3: Mean total consumption of NSAIDs POD (1 4)/at discharge t- and p-value Control ± t = FNB ± df = 140; p < Postoperative PT/Rehabilitation Schedule The aim of PT during the early PODs was to achieve independent and safe ambulation and encouraged independent stair climbing (while holding the railing). Immediate postoperative period: PT (ankle pump and active knee range-of-motion exercises, SLR) was started as the effect of anesthesia weans off and patient was comfortable. POD 1: Ambulation exercises using long knee brace and walker; gait training and full weight bearing was encouraged (as tolerated); POD 2: Cane walking stick was encouraged (as per patient comfort and confidence); POD 3: After achieving independent weight bearing with cane, they were allowed staircase climbing; POD 4: The patient was discharged. Further rehabilitation was carried out by a home visiting physical therapist. Outcomes Measured The present study recorded and evaluated the following outcome measures. Primary outcome included risk for falling (using Tinetti Gait and Balance Instrument; total score < 19: High risk of fall), 5 TUG 6,7 (a patient who takes 13.5 seconds to complete the TUG is at high risk for falling), and other adverse effects if any. A fall was defined as an unpredicted episode where a person falls to the floor from a higher level or the same level. 8 Unintentional falls (e.g., road-traffic accidents or falls while riding a bicycle) were excluded. Secondary outcomes included pain scores (VAS 0 10) on POD 1 4/ discharge; quadriceps functions (ability to hold quadriceps tension or to lift the leg), analgesic consumption during POD 1 4, and time to discharge (duration of hospitalization). Statistical Analysis Normally distributed data are expressed as mean ± standard deviation. Comparisons between equivalent groups were performed by a two-tailed t-test. Differences were considered statistically significant at p < 0.05(two-tailed). RESULTS Table 4: Rescue analgesia Number of patients using rescue medicine (POD 1 4) χ 2 and p-value Control 97.18% (n = 69) χ 2 = FNB 7.04% (n = 5) p-value is < The result is significant at p < 0.05 The clinicodemographic variables did not show any significant difference (p > 0.05; Table 1). All the patients in both groups reported significantly less pain scores than at baseline (p < 0.05) following TKA. The GF demonstrated significantly lower VAS scores (p < 0.05) than GC during early POD 1 4 and subsequent follow-up periods (p < 0.05). At 3 months, no significant difference was found in the pain scores, but the G F had better pain relief (Table 2). Mean total hospital NSAID consumption during hospital stay was significantly reduced in GF patients when compared with the GC (p < 0.05; Table 3). Also, statistically significant percentage of patients in GC required rescue medication than GF (Table 4). The ability to perform the SLR was significantly delayed in GF patients (51.74 ± 9.90 vs ± hours after surgery; t = ; p < , p < 0.05; Table 5). Hospital stay has been shown to be significantly longer in GF (6.01 ± 1.00 vs 4.33 ± 0.50 days; t = ; p < ; Table 6). Table 5: Straight-leg raise Hours after surgery t and p-value Control ± t = ; p < FNB ± 9.90 Table 6: Hospital stay Hospital stay (days) t and p-value Control 4.33 ± 0.50 t = ; p < FNB 6.01 ± 1.00 Journal on Recent Advances in Pain, September-December 2017;3(3):

4 Vikram I Shah et al Furthermore, risk of fall was negatively correlated with the rehabilitation process (r = 0.88 [p = 0.037]). The risk of fall negatively affects the ability of patients to initiate ambulation and delayed the rehabilitation process. Of the 142 patients enrolled, 134 (94.36%) completed a 3-month prospective observation (8 patients were excluded due to periprosthetic fractures). Of these patients, none of the patients in either group has reported falls in the 6 months before surgery, whereas 37 patients (26.05%) reported falls in the 3 months after surgery. Majority of falls (97%) occurred during the first month of surgery. Twenty-eight patients (39.4%) in GF and nine patients (12.6%) in GC experienced fall or near fall during first 2 months of surgery (Table 7). The difference is significant (p < 0.05). Out of 28 patients in GF 8 (28.57%) sustained periprosthetic fractures and underwent reoperations during the follow-up (1 month) period and were therefore, excluded from the secondary outcome assessments. Out of nine patients in GC, only two (22.2%) had opening of arthrotomy and underwent resuturing of arthrotomy. At 3 months, 55 patients in GF had reported postoperative neuritis (paresthesia: Sensory abnormalities in the distribution of the femoral nerve). The incidence was significantly higher in women. During the early PODs/on day of discharge both groups had significantly longer TUG test times than in the preoperative tests (p < , t = ; df = 140). For each subsequent assessment both groups had improved TUG test time (p < 0.05). At 3 months, TUG test time in GF did not show significant difference when compared with the preoperative test timings (p = 0.69); on the contrary, GC had statistically significant difference of time (p = 0.001). The patients in GF showed a significantly longer TUG test time during subsequent follow-up evaluations when compared with GC (at 1 month: t = ; df = 132; p=0.0001; at 2 months: t = 7.724; df = 132; p = ; at 3 months: t = ; df = 132; p = 0.03; Table 8). Table 7: Postoperative falls Percentage of fall χ 2 and p-value Control 9 (12.6%) χ 2 = ; p < FNB 28 (39.4%) During early PODs, 71.83% of patients in GF and 15.49% of patients in GC achieved the total score lower than 19 points according to Tinetti index, meaning high risk of falls; 26.76% patient in GF and % patients in GC had scores between 19 and 23 points (χ 2 = ; p < ; p < 0.05), representing moderate risk of falls and 14.08% patient in GC and 1.40% patient in GF had scores between 24 and 28, indicating low risk of fall. At the end of 3 months, statistically significant percentage of patients in GF had scores less than 19 points (χ 2 = ; p < ; p < 0.05), representing high risk of falls. There were significant statistical results (Table 9). DISCUSSION The results of the present prospective study demonstrated that patients who underwent TKA experienced a worsening performance on TUG test after surgery, which is consistent with the results of a previous study demonstrating that patient who undergo TKA experience a decline in physical function. 9,10 The TUG test in GF revealed significantly longer time. In the present study, TKA patients in GF displayed significant deficit in functional performance during immediate PODs and even at 3 months after surgery when compared with the control group, indicating inadequate rehabilitation process. Femoral nerve blocks significantly impair quadriceps strength, resulting in delayed and inadequate rehabilitation process. In our study, 87% of the patients had documented weakness by the physical therapist during the early PODs. Though improvement had been appreciated during the subsequent follow-up period, they failed to show any significant difference at 3 months when compared with the preoperative assessment (p = 0.67). Authors stated that decreased quadriceps strength was primary contributor to decreased functional outcomes in patients receiving FNB. Authors suggested that in such patients a more vigorous and consistent early intervention in terms of PT must be instituted that may increase functional recovery. The aim of PT following TKA was to achieve independent and safe ambulation, to encourage independent stair climbing (while holding the railing), joint mobility, and gaining muscle strength. 11,12 Early 128 Preoperative (Baseline) Table 8: Timed Up and Go POD (1 4)/at discharge 1 month 2 months 3 months GC ± ± ± ± ± 2.12 GF ± ± ± 1.12* ± 2.51* ± 2.37* t and p-values t = t = t = t = t = df = 140 df = 140 df = 132 df = 132 df = 132 p = p = p = p = p = 0.03 *Eight patients were excluded due to periprosthetic fracture and lower pole of patella. A TUG score of 13.5 seconds was used to identify individuals at higher risk of falling

5 jorapain Total score <19 Risk of Falling after Femoral Nerve Block for Total Knee Arthroplasty Table 9: Tinetti assessment index as the risk of falls* Score between 19 and 23 Score between 24 and 28 χ 2 and p-value During early POD Control 11 (15.49%) 50 (70.422%) 10 (14.08%) χ 2 = ; p < FNB 51 (71.83%) 19 (26.76%) 1 (1.40%) At the end of 1 month Control 8 (11.26%) 48 (67.60%) 15 (21.12%) χ 2 = ; p < FNB 38 (60.31%) 23 (36.50%) 2 (3.17%) At the end of 2 months Control 3 (4.22%) 37 (52.11%) 31 (43.66%) χ 2 = ; p < FNB 27 (42.85%) 34 (53.96%) 2 (3.17%) At the end of 3 months Control 1 (1.408%) 21 (29.57%) 49 (69.01%) χ 2 = ; p < FNB 18 (28.57%) 27 (42.85%) 18 (28.57%) *<19: High risk of fall; 19 23: Moderate risk of fall; 24 28: Low risk of fall initiation of PT after arthroplasty is imperative to ensure the optimal outcomes and improving gait and balance training after surgery. 13,14 The present study reported a statistically significant increased risk for falls in patients receiving FNB following TKA compared with those without blockade. Although both groups during the first month following the surgery showed increased risk of falling, significant in GF, our results indicate that FNB may increase the persistency and frequency of falls. The present study demonstrated that 71.83% of patients in GF and 15.49% of patients in GC achieved the total score lower than 19 points according to Tinetti index, meaning high risk of falls. Even at 3 months, statistically significant percentage of patients in FNB group had scores less than 19 points, indicating high risk fall. Although the cause of these falls may be multifactorial, the authors articulated that decreased quadriceps strength was the key factor contributing to the risk of fall following TKA, further enhanced in patients receiving FNB. Furthermore, it is believed that this high risk of fall could be related to age of the patients involved (mean age ± 1.66 years) as aging provides sensory disorders of balance, postural control, and level of cognitive and motor response, which makes the individual prone to falls. 15 The present study observed a significant postoperative fall in GF (χ 2 = ; p < 0.05). Majority of falls (97%) occurred during the first month of surgery. The author suggested that as a consequence of persistent quadriceps strength deficit, these patients have increased risk of falls. Out of 28 patients who received FNB, eight (28.57%) of them sustained periprosthetic fractures. All of the patients underwent revision surgery and remained nonweight bearing for 8 weeks. These patients have reduced range of motion despite adequate PT. Our results indicate that FNB may increase the persistency and frequency of falls which is a well-documented risk. 16,17 This has been the result of speculative etiology. Previous research 18,19 also reported episode of buckling and/or fall owing to decreased quadriceps strength during PODs in patients received FNB. Previous research 20,21 has reported benefit with FNBs in terms of early ambulation and reduced length of hospitalization. The current study contradicts these findings as we have observed a significant delay in rehabilitation and early ambulation in patients received FNB, which in turn increases the risk of prolonged hospitalization. Decreased quadriceps strength, increased risk for fall, fear of fall, and age were the contributing factors. At 3 months, we found significant difference in incidence of postoperative neuritis which is secondary to block (paresthesia: Sensory abnormalities in the distribution of the femoral nerve) in patients who received a FNB and those who did not. This high incidence of postoperative neuritis was secondary to block and also due to degenerative spine. Results were consistent with those of Auroy et al 22 who had reported the residual symptoms 6 months after injury to nerve in 50% of cases. The incidence was significantly higher in women. None of the patients reported femoral nerve palsy. None of the patients in both groups reported infection, deep vein thrombosis, and local hematoma. CONCLUSION Femoral nerve block is a well-accepted adjunct for postoperative analgesia following TKR. The Tinetti and gait Journal on Recent Advances in Pain, September-December 2017;3(3):

6 Vikram I Shah et al index and TUG test time showed increased risk for falls for patients who received FNB owing to decline in physical function. Furthermore, the risk of fall was negatively correlated with the rehabilitation due to muscle weakness and fear of fall. The FNB not only delays the rehabilitation but also causes an increased risk of fall, which in turn contributes to periprosthetic fractures (the most dreaded complication), longer hospital stay, and increased cost of care. The data of the present study were alarming and should serve as a red alert to surgeons to identify vulnerable patients to fall to prevent injury. In view of these critical concerns, we cannot recommend FNB for postoperative analgesia after TKR. LIMITATIONS Sample size and follow-up were short. We did not have longitudinal data to conclude whether falls occurred for a long period. More research is desirable to inspect the relationship between risk of fall, worsening of physical function, and FNB block in the long term. ACKNOWLEDGMENT Authors would like to thank acknowledge the doctors and senior colleagues for providing fruitful and critical comments on the draft of this article. REFERENCES 1. Kandasami M, Kinninmonth AW, Sarungi M, Baines J, Scott NB. Femoral nerve block for total knee replacement a word of caution. Knee 2009 Mar;16(2): Kellgren JH, Lawrence JS. Radiological assessment of osteoarthrosis. Ann Rheum Dis 1957 Dec;16(4): Dye SF, Vaupel GL, Dye CC. Conscious neurosensory mapping of the internal structures of the human knee without intraarticular anesthesia. Am J Sports Med 1998 Nov-Dec;26(6): Kapoor D, Palta S. Ultrasound guided femoral nerve block: an essential pain management modality in emergency settings for femur fractures. Saudi J Anaesth 2010 May-Aug;4(2): Tinetti ME, Speechley M, Ginter SF. Risk factors for falls among elderly persons living in the community. N Engl J Med 1998 Dec;319(26): Podsiadlo D, Richardson S. The timed "Up & Go": a test of basic functional mobility for frail elderly persons. J Am Geriatr Soc 1991 Feb;39(2): Barry E, Galvin R, Keogh C, Hogan F, Fahey T. Is the Timed Up and Go test a useful predictor of risk of falls in community dwelling older adults: a systematic review and meta- analysis. BMC Geriatr 2014 Feb;14(1): WHO. Manual of the international statistical classification of diseases, injuries, and causes of death. 9th Revision. Vol 1. Geneva: WHO; Bade MJ, Kort WM, Stevens-Lapsley Jr. Outcome before and after total knee arthroplasty compared to healthy adults. J Orthop Sports phys Ther 2010 Sep;40(9): Ouellet D, Moffet H. Locomotor deficits before and two months after knee arthroplasty. Arthritis Rheum 2002 Oct;47(5): Enloe LJ, Shields RK, Smith K, Leo K, Miller B. Total hip and knee replacement treatment programs: a report using consensus. J Orthop Sports Phys Ther 1996 Jan;23(1): Manske PR, Gleeson P. Rehabilitation program following polycentric total knee arthroplasty. Phys Ther 1977 Aug;57(8): Labraca NS, Castro-Sánchez AM, Matarán-Peñarrocha GA, Arroyo-Morales M, Sánchez-Joya Mdel M, Moreno-Lorenzo C. Benefits of starting rehabilitation within 24 hours of primary total knee arthroplasty: randomized clinical trial. Clin Rehabil 2011 Jun;25(6): Renkawitz T, Rieder T, Handel M, Koller M, Drescher J, Bonnlaender G, Grifka J. Comparison of two accelerated clinical pathways after total knee replacement how fast can we really go? Clin Rehabil 2010 Mar;24(3): Damázio LCM, Oliveira JC, Marciano ED, Pissolati MG. Avaliação do risco de quedas e qualidade de vida dos idosos com acidente vascular encefálico. Saúde (Santa Maria) 2014 Jul-Dec;40(2): Hadzic, A.; Vloka, JD. New York School of Regional Anesthesia. Peripheral nerve blocks, principles and practice. New York: McGraw-Hill; p Selander, D. Nerve toxicity of local anesthetics. In: Lofstrom J, Sjostrand U, editors. Local anesthesia and regional blockade. Amsterdam: Elsevier Science Publisher; p YaDeau JT, Cahill JB, Zawadsky MW, Sharrock NE, Bottner F, Morelli CM, Kahn RL, Sculco TP. The effects of femoral nerve blockade in conjunction with epidural analgesia after total knee arthroplasty. Anesth Analg 2005 Sep;101(3): Sharma S, Iorio R, Specht LM, Davies-Lepie S, Healy WL. Complications of femoral nerve block for total knee arthroplasty. Clin Ortho Rela Res 2010 Jan;468(1): Yu HP, Liu ZH, Guo WS, Jiang HY, Zhao J. Effect of continuous femoral nerve block in analgesia and the early rehabilitation after total knee replacement. Zhongguo Gu Shang 2010 Nov;23(11): Wang H, Boctor B, Verner J. The effect of single-injection femoral nerve block on rehabilitation and length of hospital stay after total knee replacement. Reg Anesth Pain Med 2002 Mar-Apr;27(2): Auroy Y, Benhamou D, Bargues L, Ecoffey C, Falissard B, Mercier FJ, Bouaziz H, Samii K. Major complications of regional anesthesia in France: the SOS Regional Anesthesia Hotline Service. Anesthesiology 2002 Nov;97(5):