Saphenous neuritis: a poorly understood cause of medial knee pain

Surfer's neurapraxia - an uncommon surfing injury of the saphenous nerve

Surfer's neurapraxia is a rare surfing injury of the saphenous nerve secondary to persistent compression of the saphenous nerve along the medial thigh by the surfboard when paddling prone and while sitting upright on the board waiting for a wave. Symptoms may be nonspecific and consist of pain in the medial thigh with or without radiation along the saphenous nerve distribution (medial leg, medial ankle, medial arch of the foot). The saphenous nerve tension test can be utilized to reproduce the symptoms of surfer's neurapraxia. Treatment consists of conservative management while refractory cases may benefit from injection with local anesthetic. The authors propose the Obana Plan (WATER) for prevention of surfer's neurapraxia, consisting of Wetsuits, Abduction, Timing, Exercise, and Rest. Overall, surfer's neurapraxia is a benign condition that can be prevented and managed conservatively.

Peripheral nerve stimulation for saphenous neuralgia

BACKGROUND

Injury to saphenous nerve branches is frequent during knee surgery and can result in chronic pain. This saphenous neuralgia remains challenging to treat. Peripheral nerve stimulation (PNS) is a new potential non-pharmacologic treatment option. We present our outcomes experience using this technology in 12 patients.

METHODS

We retrospectively reviewed PNS placement for saphenous neuralgia between 2000 and 2022 at a single institution. Demographic information was collected as well as response to the device. Four-question short-form Patient-Reported Outcome Measurement Information System (PROMIS) Scores were collected before and 2 weeks, 6 weeks, and 6 months postprocedure. Specific scores included pain interference and behavior, functional mobility, depression, anxiety, and sleep impairment. Change in pain interference measured by the short-form PROMIS tool at 6 months was chosen as the primary outcome.

RESULTS

Twelve patients met inclusion criteria, with 10 patients having the full 6-month follow-up. In these 10 patients, the mean change from baseline in the short-form adjusted pain interference score (greater difference means improved pain) at 6 months was 5.8 (SD 6.5). Among all patients, average follow-up was 11.5 months (range 3-35 months). Most patients' symptoms developed after knee surgery (84%). Prior to PNS, patients underwent other treatments including cryoablation (8%), radiofrequency ablation (16%), saphenous neurectomy (16%), or surgical release of adjacent nerves (25%). Ten patients (83%) reported any improvement in symptoms while two reported no benefit. Complications occurred in four patients (33%). Two patients had the device removed and a third discontinued use. PROMIS Scores for pain, functional mobility, mood, and sleep impairment all improved.

DISCUSSION

Limited effective treatments exist for saphenous neuralgia. Our case series demonstrates the potential of PNS as a treatment for saphenous neuralgia. Comparative effectiveness studies are warranted to assess whether our effect size is clinically relevant.

Subsartorius Fascial Plane Hydrodissection as Novel Treatment for Hunter's Canal Syndrome

Saphenous entrapment neuropathy in the distal thigh most commonly occurs at Hunter's canal and is characterized by neurologic symptoms distal to the midthigh in the saphenous nerve distribution. Presented is a 23-year-old active duty female service member with left medial knee pain worse with knee flexion and extension. Evaluation raised suspicion for saphenous nerve entrapment at Hunter's canal, and ultrasound-guided subsartorius fascial plane hydrodissection was performed in addition to focused rehabilitation of the adductor and core musculature. No reports of this treatment have been published to date. This case introduces ultrasound-guided subsartorius fascial plane hydrodissection as novel treatment in Hunter's canal syndrome.

Anatomical basis for ultrasound-guided infiltration of the saphenous nerve in the subsartorial canal

The present work is aimed studying the visibility and position of the vasto-adductor membrane with ultrasonography and demonstrating that injection performed under this membrane allows to infiltrate the saphenous nerve. It was analyzed with ultrasonography in four cadaveric subjects and in 13 volunteers. This membrane was clearly visible and methylene blue was located underneath it after injection in all cadaveric subjects. This study demonstrates that it can be used as a reliable anatomic landmark when performing an injection for both regional anesthesia and in the treatment of saphenous nerve tunnel syndrome.

Nonoperative treatment of recalcitrant neuritis of the infrapatellar saphenous nerve: a case series

Background

Neuritis of the infrapatellar branch of the saphenous nerve can result from iatrogenic injury, entrapment, bursitis, or patellar dislocation. Currently, there is an unmet clinical need for treating refractory neuritis nonsurgically.

Case presentation

Three patients presented with persistent anterior knee pain caused by neuritis of the infrapatellar branch of the saphenous nerve that had got excellent but only temporary relief from steroid and local anesthetic nerve block. The neuropathic pain diagnostic Douleur Neuropathique 4 questionnaire and painDETECT questionnaire confirmed presence of neuropathic pain. After injection with 25 mg amniotic and umbilical cord particulate, the patient’s pain decreased from 7.3 before injection to 0.3 at 6 weeks postinjection. In addition, neuropathic symptoms significantly improved at 2 weeks and were not present by 6 weeks. By 63 weeks, two of the patients reported continued complete pain relief, while one patient underwent total knee replacement due to an allergy of a previously implanted unicondylar implant.

Conclusions

This case series suggests that amniotic and umbilical cord particulate may be a viable alternative to reduce pain in patients with neuropathic pain.

A Case of Medial Tibial Crest Friction Syndrome: A Rare Cause of Medial Knee Pain

Knee pain is among the most common problems in active patients, with common causes of medial knee pain including meniscal injury, osteoarthritis, medial collateral ligament (MCL) injury, and pes anserine bursopathy/distal hamstring tendinopathy. Some cases of medial knee pain are refractory to standard treatment options and may be caused by rare pathology. We present a case of medial knee pain secondary to medial tibial crest friction syndrome (MTCFS) in a 22-year-old male training for a sprint triathlon after rapidly increasing his training program. Magnetic resonance imaging revealed bone marrow and soft-tissue edema about the MTC deep to the MCL consistent with MTCFS. The patient failed a period of relative rest and activity modification, but improved with corticosteroid injection deep to the MCL in the location of his symptoms. This case highlights a potential management option for MTCFS, a disorder previously described only in radiologic literature.

Anatomical variation of the saphenous nerve path: A case report

INTRODUCTION

The saphenous nerve has great importance on the sensitivity of the lower limb. In its normal course, it enters the adductor canal and travels under the sartorius muscle, on the medial side of the thigh.

METHODS

The anatomical variation was found accidentally during routine cadaveric dissection of the thigh at the Human Anatomy Laboratory of the Department of Morphophysiology of the Faculty of Medical Sciences of Minas Gerais (FCMMG).

RESULTS

A different pattern of path of the saphenous nerve was found, which appears to perforate the sartorius muscle.

DISCUSSION

Complaints of pain in the lower limbs are highly prevalent in the adult population. Saphenous neuropathy is a pathological entity that is associated with such a clinic and may have compression or trauma as its etiology. In the context of compression, it can be caused due to the unusual nerve path, as described in the present study. In trauma, knowledge of this variation is important to prevent iatrogenic damage to nervous tissue during surgical procedures.

CONCLUSION

The anatomic variation presented may be related to the symptom of pain in the lower limbs and is also relevant in the surgical context, in order to prevent complications.

Does Compression Sensory Axonopathy in the Proximal Tibia Contribute to Noncontact Anterior Cruciate Ligament Injury in a Causative Way?-A New Theory for the Injury Mechanism

Anterior cruciate ligament injury occurs when the ligament fibers are stretched, partially torn, or completely torn. The authors propose a new injury mechanism for non-contact anterior cruciate ligament injury of the knee. Accordingly, non-contact anterior cruciate ligament injury could not happen without the acute compression microinjury of the entrapped peripheral proprioceptive sensory axons of the proximal tibia. This would occur under an acute stress response when concomitant microcracks-fractures in the proximal tibia evolve due to the same excessive and repetitive compression forces. The primary damage may occur during eccentric contractions of the acceleration and deceleration moments of strenuous or unaccustomed fatiguing exercise bouts. This primary damage is suggested to be an acute compression/crush axonopathy of the proprioceptive sensory neurons in the proximal tibia. As a result, impaired proprioception could lead to injury of the anterior cruciate ligament as a secondary damage, which is suggested to occur during the deceleration phase. Elevated prostaglandin E2, nitric oxide and glutamate may have a critical neuro-modulatory role in the damage signaling in this dichotomous neuronal injury hypothesis that could lead to mechano-energetic failure, lesion and a cascade of inflammatory events. The presynaptic modulation of the primary sensory axons by the fatigued and microdamaged proprioceptive sensory fibers in the proximal tibia induces the activation of N-methyl-D-aspartate receptors in the dorsal horn of the spinal cord, through a process that could have long term relevance due to its contribution to synaptic plasticity. Luteinizing hormone, through interleukin-1β, stimulates the nerve growth factor-tropomyosin receptor kinase A axis in the ovarian cells and promotes tropomyosin receptor kinase A and nerve growth factor gene expression and prostaglandin E2 release. This luteinizing hormone induced mechanism could further elevate prostaglandin E2 in excess of the levels generated by osteocytes, due to mechanical stress during strenuous athletic moments in the pre-ovulatory phase. This may explain why non-contact anterior cruciate ligament injury is at least three-times more prevalent among female athletes.

Chronic Lower Leg Pain in Athletes: Overview of Presentation and Management

BACKGROUND

Athletes with chronic lower leg pain present a diagnostic challenge for clinicians due to the differential diagnoses that must be considered.

PURPOSE/QUESTIONS

We aimed to review the literature for studies on the diagnosis and management of chronic lower leg pain in athletes.

METHODS

A literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). The PubMed, Scopus, and Cochrane library databases were searched, and articles that examined chronic lower leg pain in athletes were considered for review. Two independent reviewers conducted the search utilizing pertinent Boolean operations.

RESULTS

Following two independent database searches, 275 articles were considered for initial review. After the inclusion and exclusion criteria were applied, 88 were included in the final review. These studies show that the most common causes of lower leg pain in athletes include medial tibial stress syndrome, chronic exertional compartment syndrome, tibial stress fractures, nerve entrapments, lower leg tendinopathies, and popliteal artery entrapment syndrome. Less frequently encountered causes include saphenous nerve entrapment and tendinopathy of the popliteus. Conservative management is the mainstay of care for the majority of cases of chronic lower leg pain; however, surgical intervention may be necessary.

CONCLUSIONS

Multiple conditions may result in lower leg pain in athletes. A focused clinical history and physical examination supplemented with appropriate imaging studies can guide clinicians in diagnosis and management. We provide a table to aid in the differential diagnosis of chronic leg pain in the athlete.

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

Background

Injury 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 presentation

A 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.

Conclusions

IBSN 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.

Neurodynamic tests for patellofemoral pain syndrome: a pilot study

Background

Patellofemoral pain syndrome (PFPS) is a common musculoskeletal disorder. There is little consensus on the etiology, but one explanatory model suggests that PFPS can be caused by referred pain. Neurodynamic tests are used to explore the mechanosensitivity of peripheral nerves, and previous studies have shown a relationship between increased mechanosensitivity and anterior knee pain by using the femoral slump test (FST). Previously the prone knee bend test (PKB) does not appear to have been included. The main purpose of this pilot study was to examine whether there was an identifiable difference in mechanosensitivity between left and right sides that could be identified using both the PKB and FST tests for the femoral nerve in patients with unilateral PFPS.

Methods

This cross-sectional pilot study tested 12 patients with unilateral PFPS for altered mechanosensitivity using both PKB and FST. The pain-free knee was used as a control. The selected test procedures were similar to those clinicians use in everyday practice.

Results

8 and 4 of the 12 patients were found to have increased levels of mechanosensitivity in the PFPS leg using the PKB and FST, respectively. Both tests provoked stronger pain in the leg with PFPS compared with the asymptomatic leg (p < 0.05 Wilcoxon Signed Rank Test). The symptoms were more often located in the anterior knee, with structural differentiation by neck flexion appearing to increase the symptoms more when testing the leg with PFPS.

Conclusions

Although the reliability of the tests is unknown and the study sample size was small, the PKB and FST test procedures used in clinical practice appear capable of revealing altered mechanosensitivity in unilateral PFPS patients. The PKB test appears to detect mechanosensitivity in more patients than the FST. We recommend including both tests in future larger blinded controlled studies which should also assess reliability of the tests.

Trial registration

ISRCTN 12473526. Registered 20 May 2015, retrospectively registered.

Treatment of a calcific bursitis of the medial collateral ligament: a rare cause of painful knee

Medial knee pain is common in clinical practice and can be caused by various conditions. In rare cases, it can even be by calcific bursitis of the medial collateral ligament (MCL). Treatment of calcific bursitis and/or calcification of the MCL classically includes observation, local injections, shockwave therapy and surgical resection. We report a case of nontraumatic medial knee pain poorly responsive to conservative treatments. Ultrasound (US) imaging revealed a massive lobed hyperechoic formation with partial acoustic shadow in the MCL context compatible with calcific bursitis, and magnetic resonance imaging (MRI) confirmed the presence of the bursa's calcific deposit surrounded by hyperintense signal compatible with pericalcific edema. We performed a double-needle ultrasound-guided percutaneous lavage (UGPL), which is today a fairly common treatment for many musculoskeletal disorders, such as rotator cuff calcific tendinopathy and elbow extensor tendons pathology, but regarding the knee, it is not part of ordinary care. This report shows the clinical and imaging presentation of calcific bursitis of the MCL and describes in detail the technique to perform the UGPL with a system of two needles, two syringes and a double connection to ensure a correct lavage of the calcium deposit without significant intrabursal pressure increase and consequently without pain during the procedure.

Entrapment Neuropathy of the Infrapatellar Branch of the Saphenous Nerve: Treated by Partial Division of Sartorius

We describe a case of entrapment neuropathy of the infrapatellar branch of the saphenous nerve as it pierces sartorius muscle. This is a rare cause of anteromedial knee pain that is easily overlooked and may be mistaken as arising from other anatomical structures in that region. The pain was successfully treated by partially dividing the sartorius muscle and translocating the nerve away from the site of entrapment. It is important to consider entrapment neuropathy of the infrapatellar branch of the saphenous nerve as a differential diagnosis when assessing a patient with anteromedial knee pain.

Adductor Canal Compression Syndrome in a 46-Year-Old Female Patient Leading to Acute External Iliac, Femoral, and Popliteal Artery Thrombosis and Critical Ischemia: A Case Report

The adductor canal compression syndrome is one of the several rare nontraumatic causes of arterial occlusions, which may lead to critical ischemia of the lower limb. We report the case of a 46-year-old athletic woman, who suffered from activity-related paresthesia and sharp pain in the left upper and lower leg for 2 years. Imaging and neurological investigations of the spine remained without pathological findings that would explain the patient's complaints. Actually, the patient presented with symptoms of critical lower limb ischemia. Magnetic resonance angiography revealed nearly complete thrombotic occlusion of the common femoral artery and the arteries of the lower leg. An emergency surgery was performed, revealing an external compression of the superficial femoral artery in the adductor canal. Subsequently, a thrombectomy was performed and a venous bypass graft was installed. No postoperative complications occurred, the patient recovered well and could return to her activities of daily living about 3 weeks after the surgery. The adductor canal compression syndrome results from a local anomalous musculotendinous band or hypertrophic musculature surrounding the passing structures. It mainly occurs in athletes exposed to repetitive stress, especially runners and skiers, and may lead to thrombosis followed by critical lower extremity ischemia. The lack of obvious symptoms during routine physical examination often impedes rapid diagnosis and timely therapy. Considering the high thrombotic risk, attention should be paid to this rare cause of lower limb pain to prevent the patient from critical lower extremity ischemia and potential limb loss due to consecutive acute thrombotic occlusions.

Localization of the Lateral Retinacular Nerve for Diagnostic and Therapeutic Nerve Block for Lateral Knee Pain: A Cadaveric Study

BACKGROUND

The lateral retinacular nerve (LRN) is a branch of the superior lateral genicular nerve (SLGN) and is believed to contribute to anterolateral knee pain. The precise anatomical pathway of the LRN, however, has not been demonstrated as it relates to the performance of targeted nerve block procedures.

OBJECTIVE

To describe the anatomical landmarks for localization of the LRN to facilitate diagnostic and therapeutic nerve blocks in the treatment of chronic anterolateral knee pain.

DESIGN

Descriptive study.

SETTING

Anatomy dissection laboratory in an academic institution.

METHODS

Twenty lower extremities were dissected in 12 cadavers. The sciatic nerve was identified, and its branch to the posterior aspect of the knee, the SLGN, was dissected. The SLGN dissection was continued distally to identify its first branch, the LRN. Two measurements were taken from the branch point on the lateral knee deep to the distal biceps tendon in alignment with the fibular head. A validation study completed in 4 knees was performed as follows: 1 mL of colored dye was injected at the first and second measurements. The cadaveric knee was then dissected to assess the accuracy.

MAIN OUTCOME MEASUREMENTS

Localization of the branch point of the LRN from the SLGN via dissection and then direct assessment of injected dye at the measurement points via dissection.

RESULTS

The branch point of the LRN from the SLGN was, on average, 5.5 ± 0.66 cm (with a range of 4.5-7.0 cm) proximal to the lateral tibiofemoral joint line in line with the head of the fibula and 2.6 ± 0.62 cm (2.0-4.5 cm) proximal to the tip of the lateral femoral epicondyle. On assessment of the 2 measurements, the measurement 5.5 cm proximal to the lateral joint line accurately targeted the branch point in 100% (4/4) of the knees, whereas the measurement 2.6 cm proximal the tip of the lateral femoral epicondyle accurately targeted the branch point in 75% (3/4) of the knees.

CONCLUSION

The results of this study provide 2 dependable landmarks and a description of the path of the LRN, making it possible to accurately target the LRN to diagnose and alleviate lateral knee pain.

Chronic leg pain in athletes

Chronic leg pain is commonly treated by orthopaedic surgeons who take care of athletes. The sources are varied and include the more commonly encountered medial tibial stress syndrome, chronic exertional compartment syndrome, stress fracture, popliteal artery entrapment syndrome, nerve entrapment, Achilles tightness, deep vein thrombosis, and complex regional pain syndrome. Owing to overlapping physical examination findings, an assortment of imaging and other diagnostic modalities are employed to distinguish among the diagnoses to guide the appropriate management. Although most of these chronic problems are treated nonsurgically, some patients require operative intervention. For each condition listed above, the pathophysiology, diagnosis, management option, and outcomes are discussed in turn.

Anatomy of the Hunter's canal and its role in the venous outlet syndrome of the lower limb

BACKGROUND

The "Adductor canal syndrome" has been described as an unusual cause of acute arterial occlusion inside the Hunter's canal in young sportsmen. It may also produce a compressive neuropathy of the saphenous nerve. To our knowledge, femoral vein compression in the canal has never been reported.

OBJECTIVE

To describe the anatomy, to propose a physiology of this canal, and to show that the femoral vein is much more exposed than the artery to compression inside this adductor hiatus, particularly at the outlet.

MATERIAL AND METHODS

The whole adductor canal was exposed in 100 limbs for anatomical study following latex injection. A series of 200 phlebographies and 100 CT venograms were also analyzed.

RESULTS

Anatomically, we found a musculotendinous band called the "vastoadductor membrane," which jointed the adductor tendon to the vastus medialis in all the cases. The femoral vein, located more posteriorly, was frequently narrowed at this level. This band can create a notch with a venous stenosis at the outlet of the Hunter's canal, usually located 12-14 cm above the femoral condyle. Two femoral valves constitute the landmark of the canal on the venograms: the lower is just below the outlet, 9 cm above the condyle. The second valve is 3 cm higher inside the canal.Functionally, the cadaveric simulations showed that the contraction of the adductor longus closes the hiatus, while the adductor magnus opens it. Our hypothesis is that Hunter's canal prevents femoropopliteal axis reflux by synchronizing with calf pump ejection during ambulation.

CONCLUSION

Compression of the femoral vein inside the adductor's canal is an underestimated and misdiagnosed cause of postural stenosis of the femoral vein. Ultrasound investigation of both limbs in patients with chronic venous disease (CVD) should be systematically carried out at this precise level in order to prevent future occlusion and onset of acute deep vein thrombosis.

Saphenous neuropathy secondary to extraneural ganglion cyst 15 years after reconstruction of the anterior cruciate ligament

This case report describes a 43-year-old woman with a previous anterior cruciate ligament reconstruction and medial meniscectomy who presented with right knee dysesthesias radiating into her medial ankle with associated allodynia. An extensive work-up was pursued, without a definitive diagnosis found or improvement in the patient's symptoms. Eventually, she was referred to Pain Medicine for an ultrasound-guided saphenous nerve (SN) block, where a scan before the injection revealed a large cyst anteromedial to the sartorius in the expected location of the SN. Magnetic resonance imaging and surgical pathology confirmed a juxta-articular ganglion cyst compressing the main SN, just above the take-off of the infrapatellar branch. The cyst was successfully resected, with improvement noted in the patient's neuropathic symptoms postoperatively. Saphenous neuropathy is a rare condition, and to our knowledge this case is the first reported of saphenous neuropathy caused by a knee joint capsule-derived ganglion cyst.

Influence of knee flexion and atraumatic mobilisation of infrapatellar fat pad on incidence and severity of anterior knee pain after tibial nailing

We evaluated the incidence and aetiology of anterior knee pain (AKP) in a series of patients that underwent intramedullary nailing for stabilisation of tibial fractures. During the preparation of the entry site no excision of the infrapatellar fat was allowed and electrical haemostasis was kept at the lowest level. Medullary canal was reamed and the nails inserted in position of knee flexion over 100 degrees. All fractures were fixed using medial paratendinous approach. Functional outcome was measured using Lysholm knee score. The knee range of movement and return to previous level of activity were also documented and analysed. Mean follow up was 38.9 months (range 12-84 months). In total 60 patients with 62 tibial shaft fractures were analysed. The mean age at the time of final follow up was 49.4 years (range 20-87). In 22 (35.5%) a newly developed and persisting pain in the anterior region of the operated knee was reported. According to VAP scale, the pain was mild (VAS 1-3) in 12 cases (19.4%) and moderate (VAS 4-6) in 10 (16.1%). In 16 cases (73%) the pain was noticed 6-12 months after injury and subjectively related to return to full range of working and recreational activities. The mean Lysholm knee score in the group without AKP was 90.8. In the AKP group with mild pain it was 88.4 and in the group with moderate AKP it was 79.9. Complete return to previous professional and recreational activities occurred in 49/60 patients (81.7%). Content with the treatment regarding expectations in recovery dynamics and return to desired level of activity was present in 98.3% of patients; one patient was unsatisfied with the treatment. Our results indicate that respecting the physiological motion of Hoffa pad and menisci during knee flexion, accompanied with atraumatic mobilisation of retrotendinous fat, reduces incidence and severity of anterior knee pain following intramedullary fixation of tibial shaft fractures.

Sonoanatomic variation of pes anserine bursa

BACKGROUND

The pes anserine bursa lies beneath the pes anserine tendon, which is the insertional tendon of the sartorius, gracilis, and semitendinosus muscles on the medial side of the tibia, but it can lie in different sites in the medial knee. Accurate diagnosis of the position of the bursa is critical for diagnostic and therapeutic goals. The aim of this study was to evaluate sonoanatomic variations of the pes anserine bursa in the medial knee.

METHODS

One hundred seventy asymptomatic volunteers were enrolled in this study. Using ultrasound imaging (transverse approach, 7-13 MHz linear array probe) the sonoanatomic position of the pes anserine bursa and its relation to the pes anserine tendon were evaluated. Additionally, we evaluated the sonoanatomic variation of the saphenous nerve.

RESULTS

The position of the pes anserine bursa was between the medial collateral ligament and the pes anserine tendons in 21.2%/18.8% (males/females) of subjects; between the pes anserine tendons and the tibia in 67.1%/64.7% (m/f); and among the pes anserine tendons in 8.2%/12.9% (m/f). No significant differences in the position of the bursa existed between males and females. The saphenous nerve was found within the pes anserine tendons in 77.6%/74.1% (m/f) of subjects, but outside the pes anserine tendons in 18.8%/15.3% (m/f). Visibility of sonoanatomic structures was not related to either gender or BMI.

CONCLUSIONS

Ultrasound provides very accurate information about variations in the pes anserine bursa and the saphenous nerve. This suggests that our proposed ultrasound method can be a reliable guide to facilitate approaches to the medial knee for diagnostic and therapeutic objectives.

Conservative management of a saphenous nerve entrapment in a female ultra-marathon runner

Entrapment of the saphenous nerve is a frequently overlooked cause of medial knee pain. Delayed or misdiagnosis is a result of a lack of detailed reporting of the vastoadductor membrane, and by direct visualization of the entrapment only being accomplished at the time of surgical decompression. To date there are no documented conservative interventions discussed in the literature. This is a case of diagnosis and conservative resolution of a spontaneous saphenous nerve entrapment in a competitive female ultra-marathon runner. In-office Active Release Technique(®) combined with an at-home rehabilitative exercise program relieved the patient's subjective pain and paresthesia with two treatments provided over a one week period of time.

The posteromedial knee arthroscopy portal: a cadaveric study defining a safety zone for portal placement

PURPOSE

To define a neurovascular safety zone for proper placement of at least 2 posteromedial (PM) portals and to describe a safe intra-articular entrance point based on the location of the PM capsular folds.

METHODS

Arthroscopy was performed on 10 fresh-frozen cadaveric knees. With the knee flexed 90°, PM portals were created under direct visualization with a 70° arthroscope. The anatomic soft spot between the PM edges of the femoral condyle and the proximal tibia was palpated, and 18-gauge spinal needles were inserted into the joint followed by 5.0-mm cannulas. The PM capsular folds were used to guide portal locations. Four portals (A, B, C, and D) were created in each of the first 3 knees. Portal position was described in relation to the soft spot: through the soft spot (A), 1 cm superior (B), 1 cm posterior (C), and 1 cm inferior (D). Dissection was performed along the path of the cannulas.

RESULTS

In the first 3 knees, the most inferior portal (D) always overlapped the course of the saphenous nerve, and the posterior portal (C) always pierced the gastrocnemius musculotendinous junction. Therefore these portals were eliminated from further study for safety reasons, and in the final 7 knees, we studied only the remaining 2 portal placements (A and B). Portals A and B were found to be the safest, with at least 1.5 cm of clearance between the portals and the saphenous nerve in all specimens.

CONCLUSIONS

At least 2 PM portals can be safely placed in the knee. The soft spot is an appropriate landmark to ensure safe portal entry. The PM capsular folds can help guide intra-articular placement so that damage to surrounding structures can be avoided.

CLINICAL RELEVANCE

We believe that 2 portals would be beneficial when performing complex arthroscopic procedures involving the PM compartment of the knee.

Peripheral nerve entrapments of the lower leg, ankle, and foot

Peripheral nerve entrapments are a relatively rare and heterogeneous group of nerve disorders encompassing a wide variety of etiologies and clinical presentations. These conditions can present significant diagnostic challenges, owing to both the variety of symptoms these patients display, along with the anatomic variation that exists between individuals. Precise knowledge of the anatomic course, the common motor and sensory distributions of each of the peripheral nerves, and judicious use of imaging or electrodiagnostic testing can greatly assist in arriving at a correct diagnosis. In this article, we discuss in detail the anatomy, clinical presentation, diagnosis, and treatment options for peripheral nerve entrapments of the lower extremity involving the sural, saphenous and common, superficial, and deep peroneal nerves.

The connective tissue of the adductor canal--a morphological study in fetal and adult specimens

The adductor canal is a conical or pyramid-shaped pathway that contains the femoral vessels, saphenous nerve and a varying amount of fibrous tissue. It is involved in adductor canal syndrome, a claudication syndrome involving young individuals. Our objective was to study modifications induced by aging on the connective tissue and to correlate them to the proposed pathophysiological mechanism. The bilateral adductor canals and femoral vessels of four adult and five fetal specimens were removed en bloc and analyzed. Sections 12 microm thick were obtained and the connective tissue studied with Sirius Red, Verhoeff, Weigert and Azo stains. Scanning electron microscopy (SEM) photomicrographs of the surfaces of each adductor canal were also analyzed. Findings were homogeneous inside each group. The connective tissue of the canal was continuous with the outer layer of the vessels in both groups. The pattern of concentric, thick collagen type I bundles in fetal specimens was replaced by a diffuse network of compact collagen bundles with several transversal fibers and an impressive content of collagen III fibers. Elastic fibers in adults were not concentrated in the thick bundles but dispersed in line with the transversal fiber system. A dynamic compression mechanism with or without an evident constricting fibrous band has been proposed previously for adductor canal syndrome, possibly involving the connective tissue inside the canal. The vessels may not slide freely during movement. These age-related modifications in normal individuals may represent necessary conditions for this syndrome to develop.

Anterior knee pain following the lateral parapatellar approach for tibial nailing

BACKGROUND

Anterior knee pain after intramedullary nailing of tibial shaft fractures is a common clinical problem, with various etiologies. We have used a lateral parapatellar approach with atraumatic elevation of the infrapatellar fat pad to expose the starting point. Our hypothesis was that this approach leads to a low incidence of knee pain.

METHODS

We conducted a retrospective study of 78 patients suffering from tibia fractures treated by a single surgeon. Fifty patients were available for the study. All fractures were fixed with a reamed intramedullary nail using the modified lateral approach. Complaints of knee pain and range of motion as well as keeling ability were examined in the clinic visit and recorded in the patients' charts. Lysholm knee scores were collected following the last follow-up visit. Average follow-up was 13 months (range 6-26 months).

RESULTS

Nine patients (19%) had subjective anterior knee pain when directly questioned. Eighty-two percentage of patients had no difficulty kneeling and this was significantly correlated with lack of knee pain. Good or excellent knee scores were reported by 92% of patients. Average knee flexion was 130 degrees . There was a negative correlation between the presence of open fracture and outcome. No correlation was found between knee pain and nail insertion depth or coronal alignment.

CONCLUSION

The modified lateral parapatellar approach with careful dissection of the fat pad may significantly reduce anterior knee pain after intramedullary nailing of the tibial shaft.

Anatomy and potential clinical significance of the vastoadductor membrane

Few reports are found in the extant medical literature regarding the vastoadductor membrane. This membrane effectively creates a subcompartment within the subsartorial canal. The lower limbs of 16 embalmed adult cadavers were dissected to identify the vastoadductor membrane and note its measurements. A vastoadductor membrane was identified in all specimens and was derived from the medial intermuscular septum. This membrane connected the medial edge of the vastus medialis muscle to the lateral edge of the adductor magnus muscle. Membranes were all wider proximally and narrowed distally. The mean length of this structure was 7.6 cm. The mean width of the vastoadductor membrane at its proximal, midportion, and distal parts was 2.2, 1.7, and 0.5 cm, respectively. The mean distance from the anterior superior iliac spine to the proximal border of the vastoadductor membrane was 28 cm. The mean distance from the distal border of the membrane to the adductor tubercle was 10 cm. Seventy-five percent of specimens exhibited a fenestrated vastoadductor membrane. Branches of the saphenous nerve to the skin of the medial thigh pierced the vastoadductor membrane in 31% of specimens. Two specimens demonstrated branches derived from the branch of the obturator nerve that pierced this membrane en route to the skin of the medial thigh. Perforating venous branches from the great saphenous vein were identified in 22% of specimens. As compression of the femoral artery at the adductor hiatus is a well-recognized entity, the clinician may also try to explore potential compression of this vessel more proximally by an overlying vastoadductor membrane. The authors would also hypothesize that due to the interconnection between the adductor magnus and vastus medialis by the vastoadductor membrane that a potential synergy exists between the functions of these two muscles.

Ultrasound of the nerves of the knee region: Technique of examination and normal US appearance

The diagnosis of disorders of the peripheral nerves (PN) has traditionally been based on clinical and electrophysiological data since nerve tissue cannot be visualized on standard radiographs. More recently, however, nerve structures have been evaluated with magnetic resonance imaging (MRI) and ultrasound (US). The former modality is expensive and not available in all institutions. There are also some contraindications to its use, and the assessment of long nerves can be time-consuming since different coils must be used. Thanks to recent advances in sonographic software and hardware, US can now be used for in-depth assessment of the PN of the upper and lower limbs.Most knee disorders involve lesions to the cruciate ligaments and/or the menisci, which are difficult to evaluate with US. However, similar symptoms may be caused by compression of one or more nerves in the knee region or intrinsic disorders involving these structures. Because of their superficial positions, the nerves around the knee can be clearly visualized with US. A thorough knowledge of the normal anatomy of this region and a careful scanning technique are essential for a successful diagnostic US examination. In this article, we will review the normal gross and microscopic anatomy of the nerves in the knee region, the US technique used for their examination, and their normal US appearance.

Anterior knee pain: diagnosis and treatment

Anterior knee pain is a frequent clinical problem. It provides a common challenge to diagnose and manage. Basic science studies have provided insight into the origin of anterior knee pain and refined understanding of the anatomy. Clinical evaluation has progressively focused on the contribution of the entire lower extremity to patellofemoral function. Nonsurgical management has been refined by the concept of the "envelope of function" and by increased understanding of the neuromuscular control of the knee. Indications for lateral release have been clarified and narrowed. Although anteromedial transfer of the tibial tuberosity is helpful in certain circumstances, reports of postoperative fracture have led to less aggressive rehabilitation protocols. Chondral resurfacing of the patellofemoral joint and patellofemoral arthroplasty are evolving. Emphasis should remain on nonsurgical management, which is sufficient in most patients.

Surgical approaches to the posteromedial and posterolateral aspects of the knee

Surgical approaches to the posterior aspect of the knee are not commonly needed, and their use has become even rarer with the increasing sophistication of arthroscopic technology. As a result, physicians in orthopaedic surgical training are not often exposed to the practical use of surgical dissection around the posterior corners of the knee. For certain procedures, however, greater clinical utility and decreased surgical morbidity render focused posterior exposure the preferred alternative to the classic popliteal dissection with its wide exposure of the popliteal anatomy. Surgical indications include ligament repair or reconstruction around the posteromedial or posterolateral aspect of the knee, inside-out meniscal repair, posterior cruciate ligament tibial inlay reconstruction, and Baker's cyst excision. To minimize complications, these focused approaches require adeptness with the complex anatomy of the posterior, posteromedial, and posterolateral aspects.

Posterolateral corner reconstruction using a hamstring allograft and a bioabsorbable tenodesis screw: description of a new surgical technique

Capsuloligamentous posterolateral corner knee joint deficiencies cause increased anterior cruciate ligament forces during internal knee rotation and increased posterior cruciate ligament forces during external knee rotation. Undiagnosed posterolateral corner knee joint injury in combination with anterior cruciate ligament or posterior cruciate ligament injury can lead to failure of anterior cruciate ligament or posterior cruciate ligament reconstruction. The purpose of this technical note is to present a new posterolateral corner reconstruction technique for treating patients with chronic capsuloligamentous posterolateral corner deficiency. The technique uses a bioabsorbable tenodesis screw and a hamstring allograft to reconstruct the popliteofibular and lateral collateral ligaments.

Compression neuropathies of the lower extremity

Compression neuropathies of the lower extremity can be just as disabling as compression neuropathies in the upper extremity. The most common compression neuropathies encountered in the lower extremity affect the lateral femoral cutaneous nerve, the peroneal nerve, the saphenous nerve, the sural nerve, and the tibial nerve (including their branches). These are discussed in terms of anatomy, etiologies, manifestations, and surgical treatment.