A cadaver study on preserving peroneal nerves during ankle arthroscopy

The Superficial Peroneal Nerve Is at Risk during the "All Inside" Arthroscopic Broström Procedure: A Cadaveric Study

Background: The arthroscopic Broström procedure is a promising treatment for chronic ankle instability. However, little is known regarding the location of the intermediate superficial peroneal nerve at the level of the inferior extensor retinaculum; knowledge about this location is important for procedural safety. The purpose of this cadaveric study was to clarify the anatomical relationship between the intermediate superficial peroneal nerve and the sural nerve at the level of the inferior extensor retinaculum. Methods: Eleven dissections of cadaveric lower extremities were performed. The origin of the experimental three-dimensional axis was defined as the location of the anterolateral portal during ankle arthroscopy. The distances from the standard anterolateral portal to the inferior extensor retinaculum, sural nerve, and intermediate superficial peroneal nerve were measured using an electronic digital caliper. The location of inferior extensor retinaculum, the tract of sural nerve, and intermediate superficial peroneal nerve were checked using average and standard deviations. For the statistical analyses, data are presented as average ± standard deviation, and then they are reported as means and standard deviations. Fisher's exact test was used to identify statistically significant differences. Results: At the level of the inferior extensor retinaculum, the mean distances from the anterolateral portal to the proximal and distal intermediate superficial peroneal nerve were 15.9 ± 4.1 (range, 11.3-23.0) mm and 30.1 ± 5.5 (range, 20.8-37.9) mm, respectively. The mean distances from the anterolateral portal to the proximal and distal sural nerve were 47.6 ± 5.7 (range, 37.4-57.2) mm and 47.2 ± 4.1 (range, 41.0-51.8) mm), respectively. Conclusions: During the arthroscopic Broström procedure, the intermediate superficial peroneal nerve may be damaged by the anterolateral portal; the proximal and distal parts of the intermediate superficial peroneal nerve were located within 15.9 and 30.1 mm, respectively, at the level of the inferior extensor retinaculum in cadavers. These areas should be considered danger zones during the arthroscopic Broström procedure.

Relationships of the superficial fibular nerve and sural nerve with respect to the lateral malleolus: implications for ankle surgeons

PURPOSE

Superficial fibular nerve (SFN) and sural nerve are at risk during osteosynthesis of the lateral malleolus. The aim of this anatomical study was to describe the relationships of the superficial fibular and sural nerves with respect to the lateral malleolus.

METHODS

Nine corpses (18 ankles) were dissected, using a direct lateral approach. Measurements were recorded between the fibula and the nerves, and the pattern variations of the SFN were recorded for both right and left side to assess intra-individual variability.

RESULTS

Distance between the tip of the lateral malleolus and the piercing of fascia cruris was 111 ± 26 mm for type 1 pattern, and range was 46-161 mm all types included. 78% (14 SFN) were type 1 pattern, 17% (3 SFN) were type 2 pattern, and 5% (1 SFN) were type 3 pattern. 44% (4 specimen) had a type 1 pattern SFN on one ankle and another pattern on the other ankle. The sural nerve was always observed just posterior to the lateral malleolus.

CONCLUSION

This study demonstrated a great inter-individual variability especially for the SFN, but also an intra-individual variability with frequent different patterns between right and left leg. It is important to know the anatomical variations of the SFN and sural nerve to decrease the risk of intra operative nerve injury during direct lateral approach of lateral malleolus.

Anterocentral Portal in Ankle Arthroscopy

BACKGROUND

The anterocentral portal is not a standard portal in anterior ankle arthroscopy due to its proximity to the anterior neurovascular bundle. However, it provides certain advantages, including a wide field of vision, and portal changes become redundant. The purpose of this study was to evaluate the neurovascular complications after anterior ankle arthroscopy using the anterocentral portal.

METHODS

We retrospectively identified patients who had undergone anterior ankle arthroscopy with an anterocentral portal at our institution from 2013 to 2018. Medical record data were reviewed and patients were invited for clinical follow-up, where a clinical examination, quantitative sensory testing for the deep peroneal nerve, and ultrasonography of the structures at risk were performed. A total of 101 patients (105 arthroscopies) were identified and evaluated at a mean follow-up of 31.5 ± 17.7 months.

RESULTS

Leading indications to surgery were heterogeneous and included anterior impingement (48.6%), osteochondral lesions of the talus (24.8%), chronic ankle instability (14.3%), and fractures (8.6%). The overall complication rate was 7.6%, and no major complications were observed. In 1.9% (2/105) of the cases, the complications were associated with the anterocentral portal and included injury to the medial branch of the superficial nerve (1/105) and to the deep peroneal nerve (1/105). Injury to the deep peroneal nerve was associated with a loss of detection and nociception. There were no injuries to the anterior tibial artery. In 41.9% (44/105) of the cases, only 1 working portal was used in addition to the anterocentral portal, and in 19% (20/105) the anterolateral portal could be avoided. Ultrasonography confirmed the integrity of the deep peroneal nerve, the medial branch of the superficial peroneal nerve, and the anterior tibial artery in all patients. Patients with nerve injuries associated with the anterocentral portal showed no signs of neuroma or pseudoaneurysm.

CONCLUSION

Using a standardized technique, the anterocentral portal in ankle arthroscopy is safe with a low number of neurovascular injuries and can be recommended as a standard portal. The anterolateral portal remains associated with a high number of injuries to the superficial peroneal nerve.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Anatomic lectures on structures at risk prior to cadaveric courses reduce injury to the superficial peroneal nerve, the commonest complication in ankle arthroscopy

PURPOSE

To assess the effectiveness of cadaveric ankle arthroscopy courses in reducing iatrogenic injuries.

METHODS

A total of 60 novice surgeons enrolled in a basic cadaveric ankle arthroscopy course were divided into two groups. Group A (n = 32) was lectured on portal placement and use of the arthroscope, whereas group B (n = 28) was in addition lectured on specific portal-related complications. Following the performance of anterior ankle arthroscopy and hindfoot endoscopy, the specimens were dissected and carefully assessed for detection of any iatrogenic injuries.

RESULTS

The rate of injury to the superficial peroneal nerve (SPN) was reduced from 25 to 3.6%, in group A compared with B (p = 0.033). Injuries to the peroneus tertius or extensor digitorum longus, the flexor hallucis longus and the tibial nerve or the Achilles tendon were also reduced in group B. Overall, the number of uninjured specimens was 50% (n = 30) and higher in group B (57%) than group A (44%). Lesions to the plantaris tendon, the sural nerve or the posterior tibial artery were more common in group B, however, without reaching statistical significance. Overall, 25 (13.9%) anatomic structures were injured in anterior arthroscopy compared to 18 (5%) in hindfoot endoscopy, out of a potential total of 180 and 360, respectively (p = 0.001).

CONCLUSION

Dedicated lectures on portal-related complications have proven useful in reducing the risk of injury to the SPN, the commonest iatrogenic injury encountered in ankle arthroscopy. Hindfoot endoscopy is significantly safer than anterior ankle arthroscopy in terms of injury to anatomical structures.

An anatomical study about the arthroscopic repair of the lateral ligament of the ankle

BACKGROUND

The purpose of this anatomical study to was to determine the relationship of the structures involved in the arthroscopic repair of the anterior talofibular ligament.

METHODS

Dissection of fifteen lower leg cadaveric specimens was made and distances in the anterior direction from the reference-point at the lateral malleolus origin of the anterior talofibular ligament were measured, to the talar insertion of the ligament, to the superficial peroneal nerve at 60° and 90° in relation to the lateral malleolus axis in the sagittal plane, and to the inferior extensor retinaculum.

RESULTS

The mean±SD distance to superficial peroneal nerve from the reference-point was 25±6 (range 17-35) mm at 60°, and 32±9 (range 24-48) mm at 90° in relation to the lateral malleolus axis. The mean±SD distance to the inferior extensor retinaculum was 20±5 (range 14-29) mm. The mean±SD length of the anterior talofibular ligament was 21±4 (range 13-29) mm.

CONCLUSIONS

The superficial peroneal nerve demonstrated the greatest variance in its anatomy. An accessory incision to include the inferior extensor retinaculum in the repair should not surpass the 22mm distance from the lateral malleolus in the anterior direction, due to the risk of damaging the nerve.

Open Reduction Internal Fixation of Posterior Malleolus Fractures and Iatrogenic Injuries: A Cadaveric Study

Open reduction internal fixation of posterior malleolus fractures from a posterior approach is gaining popularity. One concern that has not been studied is the risk of iatrogenic injury to anatomical structures on the anterior ankle. The purpose of this study is to determine the proximity of these anterior structures with relation to K-wires advanced through the anterior cortex. A total of 10 cadaver ankles were utilized in the study. A posterolateral approach to the ankle was used. K-wires were advanced at varying levels above the articular surface, and then, the proximity of the wires to the following structures was determined: the neurovascular bundle, tibialis anterior (TA), and extensor hallucis longus. Overall, the structure most in danger of being injured was the TA (P < .001). This tendon was injured by 52% of all K-wires. These data suggest that K-wires should be advanced under direct fluoroscopic visualization to minimize the risk of iatrogenic injury.

LEVELS OF EVIDENCE

Level IV.

Correlation Between Visual Inspection and Ultrasonography to Identify the Distal Branches of the Superficial Peroneal Nerve: A Cadaveric Study

The anatomy of the superficial peroneal nerve (SPN) and, more precisely, of the distal branches of the SPN at the ankle has attracted interest owing to the possibility of injury when performing ankle arthroscopy. The anterolateral portal is one of the most commonly used portals in ankle arthroscopy, and the intermediate dorsal cutaneous nerve can easily be injured during portal placement. The purpose of the present study was to assess whether visual inspection and palpation of the cutaneous nerves at the ankle differed from examination with ultrasonography and whether the 2 examination techniques correlated with the anatomic location of the SPN, which was verified by cadaver dissection. First, visual examination and palpation was performed to identify the SPN, after which 12 cadaver legs from separate specimens were examined with ultrasonography to mark the course of the SPN. We then measured the distance between the nerve as identified with gross visualization/palpation and ultrasound examination, and compared these with the precise location determined by anatomic dissection. The use of ultrasonography to determine the course of the SPN was good or excellent in 11 of the 12 legs (91.7%) studied. In contrast, gross visualization/palpation was good or excellent in 4 legs (33.3%). Excellent agreement was observed between the ultrasound markings and the anatomic dissection results. However, the visual examination poorly identified the course and the anatomic variations of the nerve branches evidenced in the anatomic dissection. From these findings in cadaver specimens, ultrasound identification of the SPN and its branches is likely preferable to gross visualization/palpation before placement of the anterolateral arthroscopic portal to the ankle.

Natural history of sensory nerve recovery after cutaneous nerve injury following foot and ankle surgery

Cutaneous nerve injury is the most common complication following foot and ankle surgery. However, clinical studies including long-term follow-up data after cutaneous nerve injury of the foot and ankle are lacking. In the current retrospective study, we analyzed the clinical data of 279 patients who underwent foot and ankle surgery. Subjects who suffered from apparent paresthesia in the cutaneous sensory nerve area after surgery were included in the study. Patients received oral vitamin B₁₂ and methylcobalamin. We examined final follow-up data of 17 patients, including seven with sural nerve injury, five with superficial peroneal nerve injury, and five with plantar medial cutaneous nerve injury. We assessed nerve sensory function using the Medical Research Council Scale. Follow-up immediately, at 6 weeks, 3, 6 and 9 months, and 1 year after surgery demonstrated that sensory function was gradually restored in most patients within 6 months. However, recovery was slow at 9 months. There was no significant difference in sensory function between 9 months and 1 year after surgery. Painful neuromas occurred in four patients at 9 months to 1 year. The results demonstrated that the recovery of sensory function in patients with various cutaneous nerve injuries after foot and ankle surgery required at least 6 months.

Anterior ankle arthroscopy: indications, pitfalls, and complications

Anterior ankle arthroscopy is a useful, minimally invasive technique for diagnosing and treating ankle conditions. Arthroscopic treatment offers the benefit of decreased surgical morbidity, less postoperative pain, and earlier return to activities. Indications for anterior ankle arthroscopy continue to expand, including ankle instability, impingement, management of osteochondritis dissecans, synovectomy, and loose body removal. Anterior ankle arthroscopy has its own set of inherent risks and complications. Surgeons can decrease the risk of complications through mastery of ankle anatomy and biomechanics, and by careful preoperative planning and meticulous surgical technique.

Entrapment of the superficial peroneal nerve: an anatomical insight

Entrapment of the superficial peroneal nerve is an uncommon neuropathy that may occur because of mechanical compression of the nerve, usually at its exit from the crural fascia. The symptoms include sensory alterations over the distribution area of the superficial peroneal nerve. Clinical examination, electrophysiologic findings, and imaging techniques can establish the diagnosis. Variations in the superficial peroneal sensory innervation over the dorsum of the foot may lead to variable results during neurologic examination and variable symptomatology in patients with nerve entrapment or lesions. Knowledge of the nerve's anatomy at the lower leg, foot, and ankle is of essential significance for the neurologist and surgeon intervening in the area.

Branching patterns of the superficial peroneal nerve: implications for ankle arthroscopy and for anterolateral surgical approaches to the ankle

Ankle arthroscopic procedures offer less postoperative morbidity with faster healing times than open surgical procedures but still have associated risks. Complication rates as high as 17% have been reported. One of the most commonly reported complications is iatrogenic damage to the superficial peroneal nerve, which can result in numbness, tingling, or painful neuralgia. In the present study, we attempted to better assess the location of the superficial peroneal nerve at the ankle to improve preoperative planning and reduce complication rates. Fifty ankle specimens were dissected. A concerted effort was made to classify the location of the superficial peroneal nerve according to the Takao branching pattern, zones of the ankle, and distance to anatomic landmarks. Through our dissections, we found that most ankles have 2 nerve branches at the level of the ankle joint (Takao type II) and that the location of the superficial peroneal nerve branches at the ankle correlated directly with the ankle width. Additionally, 68% of specimens contained a nerve branch located in zone 1, where the anterolateral portal is placed, and 12% had a branch in zone 5, the location of the anteromedial portal site. The results of the present study have confirmed the wide variation in nerve location at the level of the ankle joint and serve to highlight the need for extreme caution during surgical procedures at the ankle.

Complications associated with foot and ankle arthroscopy

Despite a late start within the realm of arthroscopy, foot and ankle arthroscopy proves to be an important diagnostic and treatment tool for the foot and ankle specialist. As indication for arthroscopy increases, complications associated with foot and ankle arthroscopy must be revisited. We reviewed 405 foot and ankle arthroscopic procedures performed on 390 patients in 4 different facilities over a 3-year period extending from January 2005 to August 2008. Two-hundred-sixty foot and ankle arthroscopic procedures on 251 patients met our inclusion criteria. A total of 246 ankle and 14 posterior subtalar arthroscopic procedures were performed with a mean follow-up of 10.7 ± 3.5 months. Patient demographics, preoperative findings, intraoperative technique, and postoperative course were reviewed. We failed to identify statistically significant predictive factors for complications. Arthroscopy performed in combination with adjunctive procedures showed a trend toward higher complication rate, although statistical significance was not noted. Overall, 20 cases (7.69%) experienced arthroscopy-related complications, and this finding was comparable with previously published results. The most common complication was cutaneous nerve injury, which involved 9 cases (3.46%), and localized superficial infection, which involved 8 cases (3.08%). Injury to the superficial peroneal nerve accounted for 5 of the cutaneous nerve injuries. There were no cases of arthroscopy-related vascular injury. All cases of superficial postoperative infection resolved with antibiotic therapy, and none of the cases required return to the operating room. These results were also similar to published data.

Is the anterior tibial artery safe during ankle arthroscopy?: anatomic analysis of the anterior tibial artery at the ankle joint by magnetic resonance imaging

BACKGROUND

Pseudoaneurysm of the anterior tibial artery (ATA) after ankle arthroscopy is an uncommon complication but can cause unexpected consequences. However, its contributing factor is not fully understood.

HYPOTHESIS

Anatomic factors, such as ATA variations and the distance between the ATA and joint capsule, may contribute to the occurrence of pseudoaneurysm.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The magnetic resonance images and medical records of 358 ankle cases were analyzed. According to locations of the ATA in relation to the peroneus tertius (PT) and the extensor digitorum longus (EDL) tendon on axial magnetic resonance imaging, patients were classified as type 1 (safe type), type 2 (increased risk type), or type 3 (high-risk type). In addition, distances between the anterior joint capsule and the ATA were measured to evaluate the thickness of the anterior fat pad, which contains the ATA and anterior compartment tendons.

RESULTS

In 336 cases (93.8%), the ATA was located medial to the EDL (type 1, safe). In 7 cases (2.0%), the ATA was located lateral to the EDL and PT tendon (type 2, increased risk); and in 15 cases (4.2%), the branching artery was observed lateral to the EDL and PT tendon and the ATA was in the normal position (type 3, high risk). The mean distance between the anterior joint capsule and the ATA was 2.3 ± 1.1 mm.

CONCLUSION

In 22 (6.2%) of the 358 cases, the ATA and its branches were located near the anterolateral ankle portal, which introduces the risk of vascular damage during arthroscopic surgery. Furthermore, the mean distance between the ATA and the joint capsule was only 2.3 ± 1.1 mm, and thus the ATA is very close to the anterior working space of the ankle joint. Careful preoperative evaluation and an intra-articular procedure may reduce the risk of vascular complications attributable to ankle arthroscopy.

The risk of nerve injury with minimally invasive plate osteosynthesis of distal fibula fractures: an anatomic study

AIM

The aim of our study was to identify the structures which may be at risk of injury when using a minimally invasive technique for the osteosynthesis of the lateral malleolus and the influence of the size of the implant on the frequency of injury to these structures.

METHOD

Forty plates were percutaneously inserted in 20 cadaveric legs. The region around the plate was then dissected to examine the relation of nerves and soft tissues to the plate.

RESULTS

The superficial peroneal nerve was in direct contact with the plate in 11 of the 20 cases (55%) of the 10 hole plates. We encountered only one case of the superficial peroneal nerve skirting the proximal edge of a 6 hole plate (p = 0.0164).

CONCLUSION

Consequently we recommend meticulous attention is paid to the dissection of soft tissues in both the proximal and distal incisions. The length of the plate may be checked with intraoperative imaging prior to its insertion, and the site of both proximal and distal incisions may be marked on the skin. After careful dissection down to the bone, preserving nerves and tendons, the periosteal elevator should be introduced both from the proximal as well as the distal incisions to prepare the extra-periosteal tunnel for the insertion of the plate, in order to avoid the entanglement of the superficial peroneal nerve with the metal work, particularly in plates of longer than six holes.

Anatomic variations of neurovascular structures of the ankle in relation to arthroscopic portals: a cadaveric study of Chinese subjects

PURPOSE

To investigate anatomic variations of neurovascular structures in the ankle and the safety margin for arthroscopic portals.

METHODS

11 left and 12 right ankles from 8 female and 15 male fresh cadavers of Chinese ethnicity aged 53 to 88 (mean, 68) years were used. The ankle was standardised in a plantigrade position, zero-degree inversion, and neutral rotation. Four ankle portals, namely anteromedial (AM), anterolateral (AL), posteromedial (PM) and posterolateral (PL), were identified using 23-gauge needles. Skin and subcutaneous fat were dissected from the underlying fascia to visualise neurovascular structures. Distances were measured from: (1) the AM portal to the saphenous vein and nerve and its branches, (2) the AL portal to branches of the superficial peroneal nerves, of which the lateral one was labelled as the intermediate dorsal cutaneous branch and the medial one as the medial dorsal cutaneous branch, (3) the PM portal to the posterior tibial neurovascular bundles, and (4) the PL portal to the sural nerve.

RESULTS

The distances from (1) the AM portal to branches of the great saphenous vein and nerve, and (2) the AL portal to the intermediate dorsal cutaneous branch of the superficial peroneal nerve were short and may be an anatomic hazard. Variations were significant among the cadavers in terms of distances of the portals to the neurovascular structures.

CONCLUSION

In Chinese cadavers, variations of neurovascular structures are significant. Care must be taken to avoid inadvertent injury during ankle arthroscopy.

Effect of superficial peroneal nerve fascial penetration site on nerve conduction studies

Using nerve conduction studies (NCS) and ultrasonography, we sought to determine the stimulation site that corresponds to the site at which the superficial peroneal nerve (SPN) penetrates the fascia and yields the most accurate NCS results. NCS parameters of the SPN sensory nerve action potential (SNAP) were recorded from 37 legs at 14, 12, 9, 7, and 5 cm (S1, S2, S3, S4, and S5, respectively) proximal to the recording electrode, and analyzed by one-way analysis of variance. SPN penetration sites were visualized by ultrasonography. The mean SNAP amplitude/area (17.2 +/- 6.7 microV/9.6 +/- 4.6 microV/ms) at S3-S5 differed significantly from that at S1-S2 (11.6 +/- 4.7 microV/9.2 +/- 4.4 microV/ms) (F = 10.2, P < 0.001; F = 5.09, P = 0.0007). Ultrasonography showed that the SPN became subcutaneous between S3 and S4. Clinical application of these results should help in obtaining more accurate data during electrodiagnostic studies of conditions that involve the SPN.