Infrapatellar Branch Research Articles

Infrapatellar Branch of the Saphenous Nerve Injury: Implications for the Physical Therapist

Injury to the infrapatellar branch of the saphenous nerve (IBSN) is an underreported condition which has important implications for the physical therapist. Due to its location, the IBSN is especially vulnerable to damage following surgery, but it may also be injured through trauma or unknown causes. Patients with suspected IBSN injury may present with a variety of symptoms, including pain along the nerve distribution, paresthesia, hypoesthesia, anesthesia, and impaired functional activities and mobility. As the presence of IBSN injury may not be readily apparent, it is incumbent upon the physical therapist to recognize the signs and symptoms associated with this condition, and to administer a detailed clinical examination. Clinical evaluation can be difficult, as IBSN injury mimics many other conditions of the knee. Additionally, saphenous nerve anatomy exhibits wide variance, even within individuals, making diagnosis challenging. Upon suspicion of IBSN injury, the physical therapist should refer the patient for a comprehensive medical exam, which may include nerve blocks, nerve conduction studies, MRI, CT scan, or exploratory surgery. Most patients respond well to surgical intervention, including neurolysis or neurectomy, though conservative treatment options exist. These include nerve blocks or pharmacologic interventions. Physical therapy treatment is not well reported and may only be appropriate for specific etiologies of injury.

SKINTED: A Rare Complication After Total Knee Arthroplasty

BackgroundSurgery of the knee, injury to the infrapatellar branch of the saphenous nerve, traumatic eczematous dermatitis is a neuropathic dermatitis specific to total knee arthroplasty (TKA), occurring around the healed surgical scar area. Very few case reports exist in orthopaedic literature regarding this rare skin complication after TKA. We report a series of cases and estimated the incidence of this condition in our institute. MethodsDuring the 1-year period from January 2018 to December 2018, patients who have undergone TKA and later presented with skin lesions adjacent to the operated site were identified. Detailed history was taken, and full clinical examination was performed for all the reported cases. ResultsA total of 9 lesions in 8 patients were identified out of a total of 203 consecutive TKAs operated during the study period, with an estimated incidence of 4.4%. The mean age was 64 years (range, 58-78 years). The mean time from surgery to diagnosis was 4 months (range, 3-6 months). ConclusionsThis group of dermatitis caused due to surgical transection of the infrapatellar branch of the saphenous nerve during TKA is a rare cutaneous complication, with an estimated incidence of 4.4% from this study. Lesions typically appear lateral to the operative scar within an area of hypoesthesia. Lesions in all patients improved after topical steroid therapy with no recurrences at further follow-up. Arthroplasty surgeons should have awareness of this benign complication, thereby avoiding unwarranted additional workup and alleviating unnecessary psychological stress to the patient.

Overstride-Induced Medial Knee Desmopathy: An Exploration Case Series.

Nine runners with varied experience but similar running-gait forms presented with the insidious and progressive onset of medial knee pain. Functional tightness of the semimembranosus (SM) tendon appeared to be a concomitant factor in the pain presentation of these patients. When evaluating atraumatic medial knee pain in runners, clinicians must consider bone stress injuries and atypical conditions. A functionally tight SM may induce pain and desmopathy of the medial collateral ligament through direct fiber entanglement or cause entrapment of infrapatellar branches of the saphenous nerve or both. Relieving SM tension resulted in short-term pain reduction while eliminating the overstride during the running gait over the long term appeared to prevent recurrence.

Frequency of infrapatellar neuropathy post-total knee replacement and arthroscopic surgery in Egyptian patients

BackgroundThe infrapatellar branch of the saphenous nerve (IPBSN) contains only sensory fibers that innervate the knee regarding its anteromedial aspect and the anterior-inferior portion of its capsule. IPBSN damage has been recorded as a postoperative complication of surgery about the knee, which is manifested by pain, numbness and reflex sympathetic dystrophy. The incisions made for arthroscopy, medial arthrotomy, and anterior cruciate ligament surgery also, can causes IPBSN damage in about 0.5 to 30% of cases. We aimed to study the frequency of infrapatellar branches of the saphenous nerve entrapment/injured in Egyptian patients to find the incidence of its affection in post-operative knee surgeries and to increase the awareness of this condition.ResultsNinety patients complaining pain at the antero-medial aspect of the knee were collected and divided into 3 groups: G1 included 30 patients with a history of total knee replacement, G2 included 30 patients with a history of knee arthroscopy and G3 included 30 patients with non-specific knee pain. All patients went to clinical, electrophysiological study and laboratory measures.There was a significant statically differences of sensory nerve conduction study regarding latency and amplitude of infrapatellar nerve between the three groups and significant statically differences of clinical signs among patients of the studied groups regarding Hofmann-Tinel sign and pain provocation test.ConclusionThe entrapment/injury of IPBSN is an underestimated sometimes unrecognized cause of post-operative knee pain to many clinicians. Awareness of this condition would probably help in managing these cases to decrease post-operative pain and disability as the frequency of infrapatellar neuropathy post total knee replacement was 56.6% and post arthroscopic surgery was 63.3% in cohort of Egyptian patients.

Anatomical study of the descending genicular artery and implications for image-guided interventions for knee pain.

The descending genicular artery (DGA) has recently been mentioned as accompanying some nerves in the medial aspect of the knee joint. This could be clinically relevant as the arteries could serve as landmarks for accurate nerve capture during ultrasound-guided nerve blockade or ablation. The aim of this cadaveric study was to investigate the anatomical distribution of the DGA, assess the nerves running alongside its branches, and discuss the implications for regional anesthesia and knee pain interventions. We dissected the femoral artery (FA) all along its course to identify the origin of the DGA, from which we carefully dissected all branches, in 27 fresh-frozen human specimens. Simultaneously, we systematically dissected the nerves supplying the medial aspect of the knee from proximally to distally and identified those running alongside the branches of the DGA. The surrounding anatomical landmarks were identified and measurements were recorded. The DGA was found in all specimens, arising from the FA 130.5 ± 17.5 mm (mean ± SD) proximally to the knee joint line. Seven distribution patterns of the DGA were observed. We found three consistent branches from the DGA running alongside their corresponding nerves at the level of the medial aspect of the knee: the artery of the superior-medial genicular nerve, the artery of the infrapatellar branch of the saphenous nerve, and the saphenous branch of the DGA. The consistent arteries and surrounding landmarks found in this study could help to improve the capture of the targeted nerves during ultrasound-guided interventions.

The Accessory Medial Portal for Anterior Cruciate Ligament Reconstruction: A Safe Zone to Avoid Neurovascular Complications.

Background:The accessory medial portal (AMP) used for anatomic anterior cruciate ligament reconstruction (ACLR) is gaining popularity. This portal is routinely created at 60° of knee flexion, placing the infrapatellar branch of the saphenous nerve (IBSN) and, less commonly, the descending and superior medial genicular arteries at risk.Purpose/Hypothesis:The purpose of this study was to identify a safe zone for AMP placement in ACLR to minimize the risk of injury to the IBSN. We hypothesized that increased knee flexion angles would decrease the risk to neurovascular structures when creating an AMP.Study Design:Descriptive laboratory study.Methods:A total of 20 cadaveric (10 matched pairs) knees were used for dissection to identify the IBSN and other neurovascular structures. A 30° arthroscope was used to make the central medial portal and AMP at 3 knee flexion angles (60°, 90°, and 110°). Distances were measured from the AMP to branches of the IBSN. Safety of AMP placement was analyzed by assessing the frequency at which spinal needles pierced a neurovascular structure or violated a safe zone.Results:The superior IBSN was significantly closer to the AMP than inferior IBSN. The AMP was significantly farther from the superior IBSN at 110° (8.56 ± 5.28 mm) compared with 60° (5.63 ± 5.00 mm; P = .015) and 90° (6.69 ± 5.03 mm; P = .006). A triangular safe zone was identified at 110° of knee flexion. No neurovascular structures were pierced, and the IBSN was not present in the safe zone. At 90°, the IBSN was not pierced; however, the IBSN did violate the safe zone at 90° of knee flexion.Conclusion:The superior IBSN is at risk for iatrogenic injury with an AMP placed at 60° of knee flexion. The nerve moved distally with knee flexion. While no neurovascular structures were compromised at 90° of knee flexion, the nerve was found to course through the safe zone. A safe zone at 110° of knee flexion decreases the risk of neurovascular injury and makes the AMP safe for ACLR.Clinical Relevance:The AMP at 60° of knee flexion for ACLR poses risk to the IBSN. The IBSN did violate the safe zone at 90° of flexion. We recommend creating an AMP with increased knee flexion to 110° to decrease the risk of iatrogenic injury. When establishing an AMP, one should aim for the center of the defined safe zone, given that the spinal needle used in this study has a smaller diameter than a stab incision.

Current versus revised anatomical targets for genicular nerve blockade and radiofrequency ablation: evidence from a cadaveric model

IntroductionRecent studies have proposed revised anatomical targets to improve accuracy of genicular nerve (GN) radiofrequency ablation (RFA). This study aims to compare the accuracy of classical and revised techniques for...

Nerve Injuries in Hip and Knee Arthroplasty - Risk Factors, Diagnostic and Therapeutic Approaches

Iatrogenic nerve injuries are rare complications of total hip and knee arthroplasty, which may cause chronic pain and loss of function, severely affecting the patient's daily activities and quality of life. Nerves "at risk" include the sciatic nerve, the femoral nerve, the lateral femoral cutaneous nerve and the superior gluteal nerve during total hip arthroplasty, and the infrapatellar branch of the saphenous nerve as well as the peroneal nerve during total knee arthroplasty. Multiple procedure-related and patient-related factors have been identified to modify the risk of nerve injury in the course of lower limb joint replacement surgery. These include the surgeon's skills, the surgical approach, the type of implant fixation, the intraoperative positioning of the patient, as well as pre-existing scars, the patient's sex, age and comorbidities. Diagnostic and therapeutic approaches should be based on the aetiology of the lesion: iatrogenic nerve lesions can result from direct (compression or transection) and/or indirect (traction, ischemia) trauma. The majority of nerve injuries encountered in hip or knee arthroplasty has been referred to as "minor" nerve lesions, which generally respond very well to non-operative treatment. "Major" nerve lesions, such as complete motor nerve transection, may result in lifelong impairment. Any perioperatively encountered neurological deficit requires a meticulous diagnostic work-up and an individually tailored treatment strategy, respecting aetiology and anatomic site of the nerve lesion as well as the individual patient's needs and comorbidities.

Saphenous nerve injury after anterior cruciate ligament reconstruction: Reduced numbness area after ligamentoplasty using quadriceps tendon compared with hamstring tendon

PurposeInjury to the infra-patellar branches of the saphenous nerve (IPBSN) is the main neurological complication of anterior cruciate ligament (ACL) reconstruction procedures. Surgical technique using quadriceps tendon (QT) autograft allows a less invasive tibial approach potentially protecting the IPBSN. The aim of this study was to compare the numbness surface of the cutaneous area supplied by the IPBSN after ACL reconstruction using either hamstring tendon (HT) or QT autografts. MethodsThis was a retrospective comparative cohort study including 51 patients who underwent ACL reconstruction (27 QT and 24 HT) between January 2017 and April 2018. A sensory clinical evaluation was performed on each patient: length of the tibial scar, eventual numbness surface area and the type of sensory disorder were reported. To be considered as an IPBSN lesion, the numbness area had to spread at least one-centimeter away from the scar. ResultsThe average follow-up was 15 months. In the HT group, the numbness area surface measured 21.2 ± 19 cm2 (0–77) and the scar length was on average 31.3 ± 5.6 mm. In the QT group, the numbness area was reduced to 5 ± 10 cm2 (P = .0007) as well as the scar length (13.3 ± 2.8 mm, P < .0001). We counted five (17.8%) and 19 (76%) real IPBSN lesions in the QT and HT groups, respectively (P = .0002). Hypoesthesia was the main sensory disorder observed (87.5%). ConclusionNumbness area of the cutaneous surface supplied by the IPBSN after ACL reconstruction is reduced using QT autograft compared with HT autograft.

Clinical and electrophysiological assessment of injury to infrapatellar branch(es) of saphenous nerve during anterior cruciate ligament reconstruction using oblique incision for hamstring graft harvest: A prospective study

BackgroundOne of the complications of arthroscopic reconstruction of anterior cruciate ligament (ACL) using hamstring autograft is injury to the infrapatellar branch of the saphenous nerve (IPBSN) leading to loss of sensation around the knee. Its incidence varies according to the orientation of incision for hamstring graft harvest, with oblique incision having the lowest chance of this injury. Aim of this study was to assess clinically and electrophysiologically injury to IPBSN after ACL reconstruction using oblique incision for hamstring graft harvest. MethodsFifty patients that were scheduled to undergo arthroscopic ACL reconstruction were included. All the patients were evaluated both clinically and electrophysiologically preoperatively and at three weeks and six months postoperatively to determine injury to IPBSN. Patient satisfaction after surgery was also compared. ResultsIPBSN injury was found to be present in 12 out of 50 patients (24%). Both clinical and electrophysiological data correlated completely. The difference in the length of the skin incisions between IPBSN injured and IPBSN intact patients was found to be statistically significant (P = .0043). The difference in the satisfaction score between patients with injured and intact IPBSN was also found to be statistically significant (P = .02). ConclusionsOblique incision for hamstring graft harvest results in lower incidence of IPBSN injury and subsequent sensory loss when compared with similar studies with different skin incisions carried out in the past. Patients undergoing ACL reconstruction should be counseled preoperatively regarding this potential complication, and if this complication occurs, improvement can be expected with time.

Chronic Anterior Knee Pain in a Wrestling Athlete from a Neuroma of the Infrapatellar Branch of the Saphenous Nerve

Chronic Anterior Knee Pain in a Wrestling Athlete from a Neuroma of the Infrapatellar Branch of the Saphenous Nerve

The Impact of Leg Length on the Path of the Infrapatellar Branch of the Saphenous Nerve

ObjectiveIatrogenic injury to the infrapatellar branch of the saphenous nerve (IPBSN) is a common sequela of anteromedial incisions during knee procedures. To more accurately predict a “safe‐zone” for incisions, we investigated the correlation between the path of the nerve and the length of the leg. The origin of the IPBSN relative to the sartorius muscle (SM) was identified to compare to previous studies.Methods103 knees from 53 formalin preserved cadavers were dissected at Kansas City University of Medicine and Biosciences, Creighton University, and the University of Nebraska Medical Center. The IPBSN was located as it approached the medial aspect of the patellar ligament. The location was documented by measuring from the intersection of the patella with the medial (Point A) and lateral (Point B) borders of the patellar ligament at angles from 0°, 30°, 45°, 60° and 90° from horizontal. Leg length was determined by the distance from the tibial plateau at the intersection of the medial collateral ligament to the distal aspect of the medial malleolus. The nerve was exposed proximally to identify its origin relative to the SM.ResultsFrom Point A, at angles from 0°, 30°, 45°, 60° and 90° from horizontal, we calculated the mean minimum and mean maximum distances to the nerve. These measurements allowed the investigators to identify a “danger zone” for expected injury to the IPBSN.No correlation existed between leg length and the mean minimum distance to the nerve. However, length had a significant, but low degree of correlation to the mean maximum distance to the IPBSN that increased as the nerve approached its most distal reaches. At angles of 45°, 60°, and 90° from Point A as well as 90° from Point B, the distance to the IPBSN increased as leg length increased.We also identified variations not previously reported. In some individuals, we identified multiple nerves serving the infrapatellar area. Many had innervation originating directly from the femoral nerve in the femoral triangle. Further, the emergence of the IPBSN relative to SM differed from previous studies, with the majority of individuals having at least one nerve penetrating through rather than emerging posterior to the SM.ConclusionWe defined safe areas for incisions as −1 SD from the mean minimum distance and +1 SD from the mean maximum distance from point A. Given there was no correlation between leg length and the minimum mean distance from point A, the safe‐zone superior to the nerve is unaffected by the length of the leg. While there was a correlation between leg length and the maximum mean distance from point A at 45°, 60°, and 90°, those are outside the area of possible incisions. Therefore, the safe‐zone inferior to the nerve is also unaffected. Existing literature has not identified infrapatellar branches arising directly from the femoral nerve. Individuals with this variation would not respond well to saphenous nerve blocks, requiring a more proximal, femoral nerve block that would temporarily compromise motor function of the anterior thigh.

Anterior skin numbness after total knee arthroplasty: A prospective comparison study between diabetic and non-diabetic patients

BackgroundAnterior skin numbness from injury of the infrapatellar branch of saphenous nerve (IPBSN) and/or the anterior-inferior branch of the femoral cutaneous nerve (AIBFN) has been reported after TKA. A recent study has demonstrated no difference in skin numbness between minimally invasive and standard approach TKA. The purpose of our study was to compare the area of skin numbness following TKA in the diabetic and non-diabetic patient. Material and methods120 patients (41 type II diabetic and 74 non-diabetic) undergoing TKA were evaluated. Five diabetic patients with preoperative skin numbness were excluded. Area of anterior skin numbness was periodically evaluated with a minimum 2-year follow-up (FU). ResultsClinically, there was no difference in prevalence of skin numbness (73.2% vs 68.9%, p = 0.36) and warmness (97.6% vs 97.3%, p = 1.00) between diabetics and non-diabetics. Average area of numbness was comparable. However, duration of numbness recovery was significantly longer in diabetics (8.6 vs 5.3 months, p = 0.001). Diabetics had a higher rate of global anterior numbness (48.3% vs 22.9%, p = 0.045). Prevalence of supero-lateral skin numbness (2.6%, n = 3) correlated with the skin incision extended proximally above upper pole of patella at least 4.0 cm ConclusionThe duration of numbness recovery following TKA was significantly longer in diabetic patients.

Estudo anatômico do ramo infrapatelar do nervo safeno em humanos

Objective To perform an anatomical study of the location of the infrapatellar branch of the saphenous nerve in relation to the structures of the knee. Methods An anatomical study was performed by dissection of 18 humans knees (9 right and 9 left knees). After exposure of the infrapatellar branch and its direct and indirect branches, they were then measured. We adopted a quadrant in the medial region of the knee delimited by two transversal planes as a parameter of the study. Results In 17 of the 18 knees (94.4%) studied, a single infrapatellar branch was observed. The infrapatellar branch emerged as fibers of the womb of the sartorius muscle in 17 of the 18 knees (94.4%). In relation to the branch, we observed that in 100% of the knees the infrapatellar branch had at least one primary branch, resulting in a superior branch and an inferior branch. In 9 limbs (50% of the cases) this branch occurred outside the proposed quadrant, and, in the remaining limbs, it occurred within the quadrant. Conclusion The infrapatellar saphenous nerve branch was found in all dissected knees, and, in 94.4% of the cases, it was of the penetrating type; in 100% of the cases, it originated two primary direct branches. The direct and indirect branches presented great variability regarding their path.

Cutaneous nerve fields of the anteromedial lower limb-Determination with selective ultrasound-guided nerve blockade.

BackgroundThis study aimed to determine the peripheral cutaneous nerve fields (CNF), their variability, and potential overlap by selectively blocking the intermediate (IFCN) and medial (MFCN) femoral cutaneous nerves and the infrapatellar branch of the saphenous nerve (IPBSN) in healthy volunteers.MethodsIn this prospective study, ultrasound‐guided nerve blockades of the IFCN, MFCN, and IPBSN in 14 healthy volunteers were administered. High‐frequency probes (15–22 MHz) and 1 ml of 1% lidocaine per nerve were used. The area of sensory loss was determined using a pinprick, and all fields were drawn on volunteers' skin. A three‐dimensional (3D) scan of all lower limbs was obtained and the three CNF and their potential overlap were measured.ResultsThe mean size of innervation areas showed a high variability of peripheral CNF, with 258.58 ± 148.26 mm2 (95% CI, 169–348.18 mm2) for the IFCN, 193.26 ± 72.08 mm2 (95% CI, 124.45–262.08 mm2) for the MFCN, and 166.78 ± 121.30 mm2 (95% CI, 94.1–239.46 mm2) for the IPBSN. In 11 volunteers, we could evaluate an overlap between the IFCN and MFCN (range, 4.11–139.68 ± 42.70 mm2), and, in 10 volunteers, between the MFCN and IPBSN (range, 11.12–224.95 ± 79.61 mm2). In only three volunteers was an overlap area found between the IFCN and IPBSN (range, 7.46–224.95 ± 88.88 mm2). The 3D‐scans confirmed the high variability of the peripheral CNF.ConclusionsOur study successfully determined CNF, their variability, and the overlap of the MFCN, IFCN, and IPBSN in healthy volunteers. Therefore, we encourage physicians to use selective nerve blockades to correctly determine peripheral CNF at the anteromedial lower limb.

Infrapatellar neuralgia due to bullous morphea in postknee arthroplasty patients treated with radiofrequency

Injury or entrapment of the infrapatellar branch of the saphenous nerve (IPS) can cause persistent anterior and medial knee pain. However, IPS neuralgia because of bullous morphea is rare and not reported earlier. We present a case of IPS neuralgia after total knee replacement where the pain was attributed to local skin lesion of bullous morphea (BM). After a successful diagnostic block, radiofrequency treatment was done to provide prolonged relief. We have discussed the possible pathogenesis of nerve entrapment and pain by BM in our case and the basis of treatment by radiofrequency ablation.

Anatomical Study of the Infrapatellar Branch of the Saphenous Nerve with Applications to Knee Surgery

Anatomical Study of the Infrapatellar Branch of the Saphenous Nerve with Applications to Knee Surgery

Incidence of Encountering the Infrapatellar Nerve Branch of the Saphenous Nerve During a Midline Approach for Total Knee Arthroplasty.

Background:The infrapatellar nerve branch (IPNB) of the saphenous nerve supplies cutaneous sensation to the anterolateral knee. Given its location and variable course, the IPNB is suspected to be at risk of injury with commonly used incisions around the knee. Nerve injury may lead to painful neuroma formation. To our knowledge, no study has evaluated the incidence at which the IPNB is encountered during the anterior approach incision for a routine total knee arthroplasty (TKA). The purpose of this study was to see whether the general joint arthroplasty surgeon can identify and examine the location of the IPNB encountered during primary TKA and to determine whether these branches would be transected during a standard medial arthrotomy.Methods:Seventy-three patients (76 knees) underwent primary TKA using a standard midline approach with a medial parapatellar arthrotomy. The IPNB was identified, and the distance was measured from the inferior pole of the patella to the point where the nerve crossed the medial border of the patellar tendon. This distance was then compared with the length of the arthrotomy in the same knee to determine whether the nerve would be transected.Results:The IPNB was encountered in all knees with a mean distance of 2.82 cm (95% confidence interval, 2.58–3.06) distal to the inferior pole of the patella during the arthrotomy. Patient characteristics including sex, height, and body mass index were not markedly associated with nerve location.Conclusion:The IPNB of the saphenous nerve is at risk for injury and routinely encountered by the general orthopaedic surgeon during a standard TKA medial parapatellar approach without the aid of magnification or dye.

Neuroma of the Infrapatellar branch of the saphenous nerve following Total knee Arthroplasty: a case report

BackgroundInjury to the infrapatellar branch of the saphenous nerve (IBSN) is common during total knee arthroplasty (TKA) with a standard midline skin incision. Occasionally, painful neuromas form at the transection of nerve and cause pain and limitation of the range of motion of the knee joint.Case presentationA 70-year-old woman experienced right knee pain and stiffness for 4 years after TKA. Physical assessment revealed medial tenderness; Tinel’s sign was positive. Radiographs revealed that the prosthesis was well-placed and well-fixed. She was diagnosed with arthrofibrosis and possible neuroma after TKA. She underwent right knee exploration, neurectomy, adhesiolysis and spacer exchange. The neuroma-like tissue was sent for pathological examination. The patient recovered uneventfully and at 3-month follow-up reported no recurrence of pain or stiffness. The pathological report confirmed the diagnosis of neuroma.ConclusionsIBSN injury should be a concern if surgeons encounter a patient who has pain and stiffness after TKA. Tinel’s sign, local anesthetic injection, MRI and ultrasound could help the diagnosis and identify the precise location of neuroma. Surgical intervention should be performed if necessary.

Accuracy of fluoroscopic-guided genicular nerve blockade: a need for revisiting anatomical landmarks

Background and objectivesGenicular nerve blockade (GNB) and radiofrequency ablation (RFA) have recently emerged as treatment options for patients with chronic knee pain. However, an increasing number of anatomical studies and...