Aims. This study aimed to use intraoperative free electromyography to examine how the placement of a retractor at different positions along the anterior acetabular wall may affect the femoral nerve during total hip arthroplasty (THA) when undertaken using the direct anterior approach (THA-DAA). Methods. Intraoperative free electromyography was performed during primary THA-DAA in 82 patients (94 hips). The highest position of the anterior acetabular wall was defined as the “12 o’clock” position (middle position) when the patient was in supine position. After exposure of the acetabulum, a retractor was sequentially placed at the ten, 11, 12, one, and two o’clock positions (right hip; from superior to inferior positions). Action potentials in the femoral nerve were monitored with each placement, and the incidence of positive reactions (defined as explosive, frequent, or continuous action potentials, indicating that the nerve was being compressed) were recorded as the primary outcome. Secondary outcomes included the incidence of positive reactions caused by removing the femoral head, and by placing a retractor during femoral exposure; and the incidence of femoral nerve palsy, as detected using manual testing of the strength of the quadriceps muscle. Results. Positive reactions were significantly less frequent when the retractor was placed at the ten (15/94; 16.0%), 11 (12/94; 12.8%), or 12 o’clock positions (19/94; 20.2%), than at the one (37/94; 39.4%) or two o’clock positions (39/94; 41.5%) (p < 0.050). Positive reactions also occurred when the femoral head was removed (28/94; 29.8%), and when a retractor was placed around the proximal femur (34/94; 36.2%) or medial femur (27/94; 28.7%) during femoral exposure. After surgery, no patient had reduced strength in the quadriceps muscle. Conclusion. Placing the anterior acetabular retractor at the one or two o’clock positions (right hip; inferior positions) during THA-DAA can increase the rate of electromyographic signal changes in the femoral nerve. Thus, placing a retractor in these positions may increased the risk of the development of a femoral nerve palsy. Cite this article: Bone Joint J 2022;104-B(2):193–199

Objectives. Effective analgesia after total knee arthroplasty (TKA) improves patient satisfaction, mobility and expedites discharge. This study assessed whether continuous femoral nerve infusion (CFNI) was superior to a single-shot femoral nerve block in primary TKA surgery completed under subarachnoid blockade including morphine. Methods. We performed an adequately powered, prospective, randomised, placebo-controlled trial comparing CFNI of 0.125% bupivacaine versus normal saline following a single-shot femoral nerve block and subarachnoid anaesthesia with intrathecal morphine for primary TKA. Patients were randomised to either treatment (CFNI 0 ml to 10 ml/h 0.125% bupivacaine) or placebo (CFNI 0 ml to 10 ml/h normal saline). Both groups received a single-shot femoral nerve block (0.25% 20 ml bupivacaine) prior to placement of femoral nerve catheter and subarachnoid anaesthesia with intrathecal morphine. All patients had a standardised analgesic protocol. The primary end point was post-operative visual analogue scale (VAS) pain score over 72 hours post-surgery. Secondary outcomes were morphine equivalent dose, range of movement, side effects, and length of stay. Results. A total of 86 patients were recruited. Treatment and placebo groups were comparable. No significant difference was found in VAS pain scores, total morphine equivalent requirements, side effects, range of movement, motor block, or length of hospital stay. Conclusion. No significant advantage was found for CFNI over a single-shot femoral block and subarachnoid anaesthesia after TKA. Cite this article: Bone Joint Res 2015;4:11–16

Previous work has demonstrated vulnerability of the femoral nerve to damage by anterior acetabular retractors during THA. The aim of this study was to quantify the proximity of the femoral nerve to the anterior acetabulum, on cadaveric material and MRI studies. A standard posterior approach to the hip was carried out in 6 fresh frozen cadaveric hemipelves. Following dislocation and removal of the femoral head, measurements were taken from the anterior acetabular lip to the posterior aspect of the femoral nerve as it passed over this point. 14 MRI studies of the hip were obtained from the local PACS database (7 male, 7 female; mean age 58 (range 32–80)). T1 weighted axial scans were reviewed. Measurements were obtained from the anterior acetabular lip to the posterior surface of the femoral nerve and artery, and the cross-sectional area of iliopsoas was calculated. There was no significant difference between the mean distances to the femoral nerve in the cadaveric (24 mm) and MRI groups (25.3mm) (p=0.7). On MRI images, the distance between the acetabular wall and both the femoral artery (p=0.003) and femoral nerve (p=0.007) was significantly larger in men. The femoral artery is strikingly close to the acetabulum in females, passing a mean distance of 14.8 mm, whereas in males this was 23.9 mm. The mean femoral nerve distance was 28.7 mm in males and 21.9 mm in females. The cross-sectional area of iliopsoas was significantly smaller in women (5.97 cm. 2. compared to 11.37 cm. 2. , p<0.001). Both the femoral artery and nerve run in close proximity to the anterior acetabular lip. Care should be taken when placing instruments in this area to avoid neurovascular injury. The increased incidence of femoral nerve damage in women following THA may be due to the significantly smaller bulk of iliopsoas

We report a case of local compression-induced transient femoral nerve palsy in a 46-year-old man. He had previously undergone surgical release of the soft tissues anterior to both hip joints because of contractures following spinal injury. An MRI scan confirmed a synovial cyst originating from the left hip joint, lying adjacent to the femoral nerve. The cyst expanded on standing, causing a transient femoral nerve palsy. The symptoms resolved after excision of the cyst

Most injuries to the femoral nerve are iatrogenic in origin and occur during resection of large retroperitoneal tumours. When the defect is considerable a nerve graft is mandatory to avoid tension across the suture line. We describe two cases of iatrogenic femoral nerve injury which recovered well after reconstruction with long sural nerve grafts. The probable reasons for success were that we performed the grafting soon after the injury, the patients were not too old, the nerve repairs were reinforced with fibrin glue and electrical stimulation of the quadriceps was administered to prevent muscle atrophy. Good functional results may be obtained if these conditions are satisfied even if the length of a nerve graft is more than 10 cm

Purpose: The functional consequences of femoral nerve resection during soft tissue sarcoma management are not well described. Sciatic nerve resection with a sarcoma, once considered an indication for amputation, is now commonly performed during limb salvage. We compared the functional outcomes of femoral and sciatic nerve resections in patients undergoing wide resection of soft-tissue sarcomas. Method: The prospectively collected database from a tertiary referral center for sarcomas was retrospectively reviewed to identify patients with resection of the femoral or sciatic nerve performed during wide excision of a soft tissue sarcoma. Patient demographics, treatment, complications and functional outcomes were collected. Results: Ten patients with femoral nerve resections were identified, all women, aged 47 to 78, with large soft tissue sarcomas of varied subtypes. All patients received adjuvant radiotherapy, most pre-operatively. Six patients developed fractures with long-term follow-up, only two of which were in the prior radiation field. Musculoskeletal Tumor Society (MSTS) 1987 scores demonstrated one excellent, 4 good, and 5 fair results. MSTS 1993 scores averaged 71.4 ± 17.2 percent and Toronto Extremity Salvage Scores (TESS) averaged 61.7 ± 21.8. There were no significant differences between the functional scores for patients with femoral or sciatic nerve resections (P=1.0). Conclusion: Femoral nerve resection appears more morbid than anticipated. The falls to which patients were prone, even years after surgery, subject them to ongoing long-term risks for fractures and other injuries. Nerve-specific functional outcomes should be considered when counseling patients prior possible resection of the femoral nerve for involvement by a soft tissue sarcoma

1. Paralysis of the femoral nerve secondary to haemorrhage of the iliopsoas muscle is described. 2. Four cases are presented. None of the patients had haemophilia, but one was receiving anticoagulant treatment–the second reported case in the literature. Only one case in a non-haemophiliac not receiving anticoagulants has been described previously. We have added three more such cases. 3. This condition can usually be managed conservatively because recovery can be expected. We believe that operation is indicated only if the lesion progresses and the symptoms and signs increase. 4. These cases underline the importance of assessing the femoral nerve in patients with hip symptoms after trauma. Iliopsoas haemorrhage should be suspected as the cause of femoral nerve neuropathy in cases of trauma to the back in adolescents or in those receiving anticoagulants

The straight leg raising test and the femoral nerve stretch test exert traction on the sciatic and femoral nerve, and the lumbosacral plexus and roots. In 40 patients with a suspected L4/5 disc protrusion, ipsilateral sciatica was induced by the femoral nerve stretch test. We believe that this is a pathognomonic sign of a lateral protrusion at L4/5 level

Purpose: Multi-modal therapy remains the cornerstone of post-operative pain management following knee replacement surgery. Femoral nerve catheters and blocks have been used with success in the management of post-operative pain yet most practicing arthroplasty surgeons and anaesthesiologists are unaware of the potential complications and risks of the procedure. The purpose of this study is to report on the complications associated with these techniques following knee replacement surgery. Method: One thousand one hundred and ninety patients underwent knee replacement surgery between January 2004 and July 1, 2007 and received an indwelling continuous infusion femoral catheter for post-operative marcaine pump infusion. For the initial 469 patients (Group 1), the continuous infusion ran for 2 to 3 days. In 721 patients, the continuous infusion was discontinued 12 hours following surgery (Group 2). Results: There were 15 major complications observed in 1190 patients: 7 femoral nerve palsies (2 in Group 1, 5 in Group 2) and 8 falls (4 in each group). For the patients who had fallen in hospital, the injuries sustained were: traumatic hemarthrosis, hemarthrosis requiring arthrotomy, major wound dehiscence with exposed implants, complete medial collateral ligament rupture requiring repair, quadriceps tendon rupture requiring delayed repair, minor wound dehiscence with suture, and displaced ankle fracture. Conclusion: Femoral nerve catheters and blocks are effective tools for post-operative pain relief following knee arthroplasty surgery. However, it is important for the surgeon and anaesthesiologist to provide information regarding the potential complications of the treatment as part of an informed consent. Although the complication rate is relatively low at 1.3%, the occurrence of femoral nerve palsies as well as re-operations significantly delayed patient recovery. We did not observe a benefit in terms relative risk reduction with discontinuation of the continuous infusion 12 hours following surgery. The femoral palsies reported in our series have led our institution to adopt ultrasound guidance for catheter placement rather than tradition nerve stimulation technique, although the safety of this newer technique is currently under evaluation

1. The case of a girl aged sixteen years who avulsed the iliacus muscle from the ilium during a gymnastic exercise is reported. 2. The lesion was complicated by paralysis of the femoral nerve from pressure by the haematoma. Recovery occurred after decompression. 3. Reports of similar cases from the literature are reviewed

Study Objective: To determine the feasibility of ultrasound-guided femoral nerve blockade performed by orthopaedic trainees. Methods: This was a prospective study involving patients presenting to Acciedent & Emergency with fractured femurs requiring analgesia. Physicians performing the nerve blocks were orthopaedic trainees who had participated in a 1-hour training session. The participants underwent ultrasonography-guided femoral nerve blocks to provide analgesia. Any additional analgesia required was recorded. Subjects rated their pain on a Numerical Pain Rating Scale (NRS) before the nerve block and 30 & 60minutes after the nerve block. The primary outcomes for feasibility were the requirement for additional analgesia following injection and the median reduction in pain on the Numerical Pain Rating Scale after the nerve block. Secondary outcomes for feasibility included the median time for completion of the entire nerve block procedure for each subject (from initiation of ultrasonography to completion of the last injection) and the percentage of participants wishing to have the same procedure for similar injuries in the future. Other secondary outcomes included the percentage of participants with complications during the procedure including nerve and vascular injection. Results: All procedures (100%) were completed without additional anesthesia or analgesia with significant reduction in Numerical Pain Rating Scale. There were no immediate complications. Conclusion: Orthopaedic trainees can perform ultrasound-guided femoral nerve blocks in the emergency department with high patient satisfaction, after minimal training

Purpose. Femoral nerve blockade (FNB) can provide prolonged postoperative analgesia and facilitate rehabilitation following major knee surgery while minimizing opioid-related adverse effects. However, anecdotal data have implicated FNB in post-operative falls, presumably due to a block-related reduction in quadriceps strength. Age, gender and knee replacement surgery have also been previously identified as risk factors for falls in the acute postoperative orthopaedic inpatient setting. We hypothesized that the use of FNB would be an independent predictor of an inpatient fall following total knee replacement (TKR). Method. We examined a cohort of 2,197 patients who underwent TKR in a single academic institution between October 2003 and March 2010. The start date was based on the separate initiation of both a comprehensive regional anesthesia database and an orthopaedic ward Falls Surveillance Program. Patients undergoing revision TKR or unicompartmental arthroplasty were excluded. Age, simultaneous bilateral TKR, gender, body mass index (BMI), and various regional nerve blocks were considered predictors of post-operative falls in a logistic regression model. The database allowed resolution of the type (i.e. femoral, sciatic) and duration (i.e. single-bolus, indwelling continuous perineural catheter) of nerve blockade. Hospital-standard dosing and insertion techniques were employed. Results. The total number of falls was 60 (rate 2.7%), 40 of which occurred within 48 hours of surgery. When compared to patients who did not fall, those who fell were significantly older (699 years vs 6611 years; p=0.03), obese [BMI >30kg/m2] (75% vs 59%; p=0.01) and had continuous catheter FNB (97% vs 86%; p=0.02). The odds ratio of having a fall was 1.04 (1.0–1.07; p=0.008) for each one-year increase in age above the mean age of 66 years, 2.4 (1.3–4.5; p=0.005) for a BMI >30kg/m2 and 4.4 (1.04–18.2; p=0.04) for continuous catheter FNB. Gender, simultaneous bilateral TKR, any sciatic nerve block or spinal anesthetic did not predict an increased risk of acute-care post-operative falls. Conclusion. This is the first study to demonstrate an increased risk of post-operative falls in obese patients and with the use of continuous catheter FNB following TKR. Careful consideration of the use of continuous catheter FNB may be warranted in patients with additional risk factors for falls such as advanced age and obesity

Aims. Lateral femoral cutaneous nerve (LFCN) injury is a complication after periacetabular osteo-tomy (PAO) using an anterior approach, which might adversely affect the outcome. However, no prospective study has assessed the incidence and severity of this injury and its effect on the clinical outcomes over a period of time for longer than one year after PAO. The aim of this study was to assess the incidence and severity of the symptoms of LFCN injury for ≥ three years after PAO and report its effect on clinical outcomes. Methods. A total of 40 hips in 40 consecutive patients who underwent PAO between May 2016 and July 2018 were included in the study, as further follow-up of the same patients from a previous study. We prospectively evaluated the incidence, severity, and area of symptoms following LFCN injury. We also recorded the clinical scores at one year and ≥ three years postoperatively using the 36-Item Short Form Health Survey (SF-36) and Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ) scores. Results. A total of 20 patients (50%) had symptoms of a LFCN injury at one year after PAO. At ≥ three years postoperatively, the symptoms had completely resolved in seven of these patients and 13 (33%) had persistent symptoms. The severity and area of symptoms did not significantly differ between one and ≥ three years postoperatively. The JHEQ showed significant differences in the patient satisfaction and mental scores between those with and those without sypmtoms of LFCN injury at ≥ three years postoperatively, while there was no significant difference in the mean SF-36 scores. Conclusion. The incidence of LFCN injury after PAO using an anterior approach is high. The outcome of PAO, ≥ three years postoperatively, is poorer in patients with persistent symptoms from a perioperative LFCN injury, in that patient satisfaction and mental health scores are adversely affected. Cite this article: Bone Joint J 2024;106-B(5 Supple B):11–16

In a randomised controlled pragmatic trial we investigated whether local infiltration analgesia would result in earlier readiness for discharge from hospital after total knee replacement (TKR) than patient-controlled epidural analgesia (PCEA) plus femoral nerve block. A total of 45 patients with a mean age of 65 years (49 to 81) received a local infiltration with a peri-articular injection of bupivacaine, morphine and methylprednisolone, as well as adjuvant analgesics. In 45 PCEA+femoral nerve blockade patients with a mean age of 67 years (50 to 84), analgesia included a bupivacaine nerve block, bupivacaine/hydromorphone PCEA, and adjuvant analgesics. The mean time until ready for discharge was 3.2 days (1 to 14) in the local infiltration group and 3.2 days (1.8 to 7.0) in the PCEA+femoral nerve blockade group. The mean pain scores for patients receiving local infiltration were higher when walking (p = 0.0084), but there were no statistically significant differences at rest. The mean opioid consumption was higher in those receiving local infiltration.

The choice between these two analgesic pathways should not be made on the basis of time to discharge after surgery. Most secondary outcomes were similar, but PCEA+femoral nerve blockade patients had lower pain scores when walking and during continuous passive movement. If PCEA+femoral nerve blockade is not readily available, local infiltration provides similar length of stay and similar pain scores at rest following TKR.

Cite this article: Bone Joint J 2013;95-B:629–35.

Aims. Lateral femoral cutaneous nerve (LFCN) injury is a potential complication after the direct anterior approach for total hip arthroplasty (DAA-THA). The aim of this study was to determine how the location of the fasciotomy in DAA-THA affects LFCN injury. Methods. In this trial, 134 patients were randomized into a lateral fasciotomy (n = 67) or a conventional fasciotomy (n = 67) group. This study was a dual-centre, double-blind, prospective randomized controlled two-arm trial with parallel group design and a 1:1 allocation ratio. The primary endpoint was the presence of LFCN injury, which was determined by the presence of numbness, decreased sensation, tingling, jolt-like sensation, or pain over the lateral aspect of the thigh, excluding the surgical scar, using a patient-based questionnaire. The secondary endpoints were patient-reported outcome measures (PROMs) using the Western Ontario and McMaster Universities osteoarthritis index (WOMAC), Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ), and the Forgotten Joint Score-12 (FJS-12). Assessments were obtained three months after surgery. Results. The incidence of LFCN injury tended to be lower in the lateral fasciotomy group (p = 0.089). In the lateral fasciotomy group, there were no significant differences in the mean PROM scores between patients with and without LFCN injury (FJS-12: 54.42 (SD 15.77) vs 65.06 (SD 26.14); p = 0.074; JHEQ: 55.21 (SD 12.10) vs 59.72 (SD 16.50); p = 0.288; WOMAC: 82.45 (SD 6.84) vs 84.40 (SD 17.91); p = 0.728). In the conventional fasciotomy group, there were significant differences in FJS-12 and JHEQ between patients with and without LFCN injury (FJS-12: 43.21 (SD 23.08) vs 67.28 (SD 20.47); p < 0.001; JHEQ: 49.52 (SD 13.97) vs 59.59 (SD 15.18); p = 0.012); however, there was no significant difference in WOMAC (76.63 (SD 16.81) vs 84.16 (SD 15.94); p = 0.107). Conclusion. The incidence of LFCN injury at three months after THA was comparable between the lateral and conventional fasciotomy groups. Further studies are needed to assess the long-term effects of these approaches. Cite this article: Bone Joint J 2023;105-B(12):1252–1258

Aims. Injury to the lateral femoral cutaneous nerve (LFCN) is one of the known complications after periacetabular osteotomy (PAO) performed using the anterior approach, reported to occur in between 1.5% and 65% of cases. In this study, we performed a prospective study on the incidence of LFCN injury as well as its clinical outcomes based on the Harris Hip Score (HHS), Short-Form 36 Health Survey (SF-36), and Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ). Methods. The study included 42 consecutive hips in 42 patients (three male and 39 female) who underwent PAO from May 2016 to July 2018. We prospectively evaluated the incidence of LFCN injury at ten days, three months, six months, and one year postoperatively. We also evaluated the clinical scores, including the HHS, SF-36, and JHEQ scores, at one year postoperatively. Results. LFCN injury was observed in 31 of 42 (74%) patients at ten days, of which 11 resolved completely by one year. Incidence decreased gradually, to 25 of 42 (60%) patients at three months, 24 of 42 patients (57%) at six months, and 20 of 42 (48%) patients at one year postoperatively. There was no significant difference in the HHS between patients with and without LFCN injury at one year postoperatively. Regarding the SF-36 and JHEQ, a significant difference in the mental score was recognized between patients with and without LFCN injury, but there were no significant differences in the other clinical scores. Conclusion. The incidence of LFCN injury was 74% at ten days after PAO, and subsequently decreased to 48% at one year. LFCN injury did not influence the hip function as assessed by the HHS, but had a negative impact on mental health at one year. Cite this article: Bone Joint J 2021;103-B(4):659–664

Injury of the lateral femoral cutaneous nerve (LFCN) is one of the known complications after periacetabular osteotomy (PAO) using anterior approach. We previously reported that the incidence of LFCN injury was 48% at 1 year after PAO. However, there was no study examining the sequential changes of LFCN injury status. In this study, we performed a prospective over 3-year follow-up study as to the incidence of LFCN injury as well as its clinical outcomes. This study included 40 consecutive hips in 40 patients (3 males and 37 females) who underwent PAO from May 2016 to July 2018. The mean age at surgery was 36.7 years (17 to 60). The mean observation period was 47.3 months (36 to 69). The incidence and severity of LFCN injury was evaluated, while clinical scores, including the Harris Hip Score (HHS), Short-Form 36 Health Survey (SF-36), and Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ), were also investigated. At 3 years after PAO, LFCN injury was observed in 13 of 40 (33%) patients, in which 7 patients who had a symptom at 1 year have completely recovered. There was no significant difference in the HHS and SF-36 between patients with and without LFCN injury at 3 years. Regarding the JHEQ, a significant difference was recognized in the patient satisfaction and mental score between patients with and without LFCN injury, but there were no significant differences in the other clinical scores. The incidence of LFCN injury gradually decreased to 33% at 3 years after CPO. LFCN injury did not influence the clinician-reported outcome, while it had a negative impact on patient satisfaction and mental score based on the patient-reported outcome

Purpose: While several studies have reported improved pain control with use of femoral nerve blocks (FNB) following ACL reconstruction, there are few studies that have evaluated the effect of continuous perineural infusion on quadriceps activation and recovery of range of motion after ACL reconstruction. The purpose of this prospective randomized placebo-controlled clinical trial was to determine if the use of continuous infusion of levobupivacaine for pain control following ACL reconstruction had an adverse effect on postoperative quadriceps activation and recovery of ROM.

Method: Two-hundred-seventy patients underwent ACL reconstruction and were randomly assigned to one of three FNB groups (placebo bolus and infusion, active bolus with placebo infusion, or active bolus and continuous infusion). The patients’ ability to perform a SLR was assessed daily for the first four post-operative days. Range of motion of the knee was measured with a goniometer 1, 4, 8 and 12 weeks after surgery. Range of motion complications requiring arthroscopic debridement, manipulation under anesthesia, or application of a drop-out cast were recorded.

Results: There were no significant differences between groups in their ability to perform a SLR on postoperative day 1 through 4. There were also no differences between active and passive ROM values between groups at each follow-up period. There were 7 (3.2%) early ROM complications, but no detectable differences between groups.

Conclusion: Continuous perineural infusion of levobupivacaine (0.25% at 5mL/hr for 50 hours) following ACL reconstruction does not appear to negatively influence quadriceps activation as evidenced by the inability to perform a SLR or adversely affect recovery of range of motion in the early postoperative period after ACL reconstruction. Continuous perineural infusion can provide effective pain relief without adversely affecting post-operative recovery following ACL reconstruction.

To quantify the risk posed to the Lateral Femoral Cutaneous Nerve (LFCN) during Total Hip Arthroplasty using the Minimally Invasive Anterior Approach (MIAA), and during placement of the Anterior Portal (AP) in Supine Hip Arthroscopy (SHA). Forty-five hemipelves from thirty-nine cadavers were dissected. The LFCN was identified proximal to the inguinal ligament (IL), and its path in the thigh identified. The positions of the nerve and its branches in relation to the MIAA incision and the site for AP placement were measured using Vernier Callipers. 44% of nerves crossed the incision line used in the MIAA, at an average distance of 47 ± 28mm from the proximal end of the incision. Of those that did not cross the incision line, the average minimum distance between the nerve and incision was 14.4 ± 7.4mm, occurring on average 74.0 ± 37.3mm from the proximal end of the incision. In addition, the AP was placed in the path of the nerve on 38% of occasions. The nerve took an oblique path, and when found not to intersect with the AP portal, was located 5.7 ± 4.5mm from the portal's edge. We found a reduction in risk if the portal is moved medially or laterally by 15mm from its current location. The LFCN is at high risk of injury during both THA using the MIAA and SHA using the AP. Our study emphasises the need for meticulous dissection during these procedures, and thorough explanation of these risk whilst consenting patients. We suggest that relocation of the AP 15mm more laterally or medially will reduce the risk posed to the LFCN