Anatomy of the sural nerve with an emphasis on the incision for medial displacement calcaneal osteotomy

Comparison of Lateral and Central Achilles Tendon-Splitting Approaches in the Treatment of Haglund Deformity

BACKGROUND

This study aimed to compare the complications and outcomes of lateral and central Achilles tendon-splitting approaches for the treatment of Haglund syndrome.

METHODS

Patients who underwent surgery for Haglund syndrome between June 2012 and June 2022 were included in the study. Patients undergoing lateral approach surgery were included in group 1, whereas patients undergoing central Achilles tendon-splitting approach surgery were included in group 2. Surgical outcomes of the patients were evaluated using the American Orthopaedic Foot & Ankle Society (AOFAS) ankle hindfoot scale, visual analog pain scale (VAS), and Victorian Institute of Sport Assessment-Achilles (VISAA) scores. In addition, preoperative and final follow-up scores were compared.

RESULTS

The study included 66 patients: 32 (14 females, 18 males) underwent surgery using the lateral approach in group 1, whereas in group 2, 34 patients (18 females, 16 males) underwent surgery using the central Achilles tendon-splitting approach. There was a significant statistical difference in the AOFAS, VISAA, and VAS scores between preoperative and final follow-up for both group 1 and group 2 (P < .001, P < .001, P < .001, P < .001, respectively). Group 1 had a small (0.76) relative increase in VAS score compared with group 2 (P = .033). There was no significant difference between the complication rates of group 1 and group 2.

CONCLUSION

In our study, we found the lateral approach and central Achilles tendon-splitting approaches to be safe and effective in the surgical treatment of Haglund syndrome without clinically meaningful differences in outcomes or complication rates.

Outcomes of Combined Posterior Tibial Tendon Tendoscopy and Medializing Calcaneal Osteotomy for Stage IA Progressive Collapsing Foot Deformity

BACKGROUND

Posterior tibial tendon (PTT) tendoscopy and medializing calcaneal osteotomy (MCO) are among the available techniques for patients presenting with symptomatic flexible hindfoot valgus (stage IA) progressive collapsing foot deformity (PCFD). The aim of this study was to determine clinical and radiographic outcomes of combined PTT tendoscopy and MCO for patients presenting with symptomatic stage IA PCFD.

METHODS

A retrospective cohort study was performed in order to determine clinical and radiographic outcomes of 30 combined PTT tendoscopies and MCO on 27 patients presenting with symptomatic stage IA PCFD, with a minimum follow-up of 24 months. Patient satisfaction was assessed at last available follow-up as very satisfied, satisfied, and unsatisfied. Clinical assessment was performed evaluating preoperative and last available follow-up visual analog scale for pain (VAS-P), Foot and Ankle Outcome Score (FAOS), and the 36-Item Short Form Health Survey (SF-36). Magnetic resonance imaging (MRI) was performed preoperatively on all patients. Standard weightbearing anteroposterior, lateral, and long axial view radiographs of the foot and ankle were taken preoperatively, immediate postoperatively, at 6 weeks, 3 months, 6 months, 1 year postoperatively, and last follow-up evaluation available for each patient.

RESULTS

The mean follow-up was 38.6 (range, 26-62) months. We registered 27 very satisfied, 1 satisfied, and 2 unsatisfied patients. There was statistically significant improvement on all clinical scores (VAS-P, FAOS and SF-36), as well as on lateral talo-first metatarsal and hindfoot alignment angles. We found low-grade PTT tears in 5 patients (16.67%) in whom preoperative MRI documented PTT tenosynovitis alone.

CONCLUSION

We found that combined PTT tendoscopy and MCO provide significant clinical and radiographic improvement for patients presenting with symptomatic stage IAB PCFD. PTT tendoscopy should be considered in the treatment of all surgically addressed flexible valgus feet as it detects tendon tears which are frequently missed on an MRI.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Anatomical patterns of the sural nerve: a meta-analysis with clinical and surgical considerations

BACKGROUND

The sural nerve (SN) supplies the posterolateral aspect of the leg and the lateral aspects of the ankle and foot and descends through the gastrocnemius muscle along the lower third of leg. Because in-depth knowledge about SN anatomy is essential for clinical and surgical approaches, our study aims to review SN anatomical patterns.

METHODS

We searched the PubMed, Lilacs, Web of Science, and SpringerLink databases to find relevant articles for meta-analysis. We assessed the quality of the studies using the Anatomical Quality Assessment tool. We used proportion meta-analysis to analyze the SN morphological variables and simple mean meta-analysis to analyze the SN morphometric variables (nerve length and distance to anatomical landmarks).

RESULTS

Thirty-six studies comprised this meta-analysis. Overall, Type 2A (63.68% [95% CI 42.36-82.64]), Type 1A (51.17% [95% CI 33.16-69.04]) and Type 1B (32.19% [95% CI 17.83-48.38]) were the most common SN formation patterns. The lower third of leg (42.40% [95% CI 32.24-52.86]) and middle third of leg (40.00% [95% CI 25.21-53.48]) were the most common SN formation sites. The pooled SN length from nerve formation to the lateral malleolus was 144.54 mm (95% CI 123.23-169.53) in adults, whereas the SN length was 25.10 mm (95% CI 23.20-27.16) in fetuses in the second trimester of gestation and 34.88 mm (95% CI 32.86-37.02) in fetuses in the third trimester of gestation.

CONCLUSIONS

The most prevalent SN formation pattern was the union of the medial sural cutaneous nerve with the lateral sural cutaneous nerve. We found differences regarding geographical subgroup and subject age. The most common SN formation sites were the lower and middle thirds of the leg.

Lateral approach for insertional Achilles tendinitis with Haglund deformity

Objective

The study aims to investigate the functional outcome of the lateral approach for insertional Achilles tendinitis (IAT) with Haglund deformity.

Methods

From January 2016 to September 2019, 14 cases of IAT with Haglund deformity that resisted conservative treatment received surgery in our department. A lateral approach was used to debride the bony and soft tissue and reattach the insertion of the Achilles tendon. The Visual Analog Scale (VAS), American Orthopedic Foot and Ankle Score (AOFAS), and Victorian Institute of Sport Tendon Study Group-Achilles Tendinopathy score (VISA-A) were used to evaluate clinical outcomes.

Result

The mean patient age was 39.57 years at the time of surgery. The mean follow-up was 14.74 months. The mean VAS score significantly decreased from 4.86 ± 0.86 preoperatively to 1.21 ± 1.58 postoperatively (P < 0.001). The mean AOFAS score significantly improved from 66.64 ± 6.23 preoperatively to 90.21 ± 11.50 postoperatively (P < 0.001). The mean preoperative and the last follow-up VISA-A were 66 (range 56.75-69.25) and 86 (range 75.75-97.00) points, respectively (P < 0.05).

Conclusion

The lateral approach was effective and safe for IAT with Haglund deformity. Moreover, the mid-term functional outcome was promising.

Level of Clinical Evidence

IV.

Locating the danger zone to avoid injury to the sural nerve during Achilles calcaneal tendon repair. A systematic review of cadaveric studies with clinical implications

INTRODUCTION

Although iatrogenic injuries to the sural nerve (SN) are commonly encountered in calcaneal (Achilles) tendon (CaT) repair surgeries, the relationship between both structures have anatomical variations. A quantitative evidence synthesis has not been yet conducted. Our systematic review aims to better define the safe zone where the SN crosses the lateral border of CaT.

METHODS

Electronic databases were searched to locate relevant anatomical studies recording details regarding the distance at which SN crosses the CaT. The Checklist for Anatomical Reviews and Meta-Analyses (CARMA) was followed. The primary outcome was the mean distance from CaT insertion to SN crossing site, to locate a safe zone. The secondary outcome was the mean horizontal distance from the SN to the CaT lateral border.

RESULTS

Seven studies met the inclusion criteria with a total of 204 cadaveric limbs. The danger zone was located 2 cm distal and proximal to the mean distance of the crossing point. The mean distance from CaT insertion to the SN crossing site was 9.91 ± 0.67 cm. The mean horizontal distance between SN and the CaT lateral border decreased from a mean of 19.8 ± 2.06 mm at the calcaneal tuberosity level to 3.6 ± 0.4 mm at 10 cm proximal to the tuberosity.

DISCUSSION

This review demonstrated that 10 cm is the average distance from the CaT insertion onto the calcaneal tuberosity to the point of crossing of the SN. A safe zone would be 2 cm away proximally and distally from the crossing point. We recommend placing the proximal lateral sutures away from this region. This finding should help surgeons avoid SN injuries during open or percutaneous approaches for calcaneal tendon rupture.

Calcaneal Osteotomies in the Treatment of Progressive Collapsing Foot Deformity. What are the Restrictions for the Holy Grail?

The progressive collapsing foot deformity is a complex three-dimensional deformity, including valgus malalignment of the heel. The medial displacement calcaneal osteotomy is an established surgical procedure reliably resulting in an efficient correction of the inframalleolar alignment. However, complications are common, including undercorrection of underlying deformity, progression of hindfoot osteoarthritis and/or deformity, and/or symptomatic hardware.

Neurological Injuries after Calcaneal Osteotomies Are Underdiagnosed

The incidence of peripheral neurological injuries related to calcaneal osteotomies reported in the literature is low and often described as occasional. The main objective of this study is to determine the incidence of neurological injuries after calcaneal osteotomies and identify which nerve structures are most affected. This retrospective work included 69 patients. Medical records, surgical protocols, and radiographs were analyzed. All patients were summoned to perform current functional tests (EFAS score and SF-12), and a thorough physical examination was performed systematically and bilaterally. The total incidence of neurological injuries was 43.5% (30/69). The percentage of neurapraxias (transient injuries) was 8.7%, while 34.8% of patients presented neurological sequelae (permanent injuries). The most injured nerve or branch was, in decreasing order: sural nerve, medial plantar branch, lateral plantar branch and medial calcaneal branch. Following the so-called "safe zone" clearly decreases the incidence of sural nerve injury (p = 0.035). No significant differences were found between osteotomy site, number of screws, and type of closure and increased neurological injuries. No significant differences were found in the functional tests between the different techniques, nor between patients who presented neurological injuries and those who did not. Neurological injuries after calcaneal osteotomies are underdiagnosed and the incidence is higher than previously reported (43.5%). Such injuries mostly go unnoticed and have no implications in the functional results and patients' satisfaction.

"Safe incision" in calcaneal sliding osteotomies reduces the incidence of sural nerve injury

PURPOSE

The purpose of this study was to demonstrate whether application of the so-called safe incision when performing calcaneal sliding osteotomies reduces the risk of sural nerve injury.

METHODS

Patients who underwent either medial or lateral sliding calcaneal osteotomies between 2010 and 2018 were analysed retrospectively. A thorough neurological examination was performed, and the location of the surgical wound and the type of wound closure were recorded. The European Foot and Ankle Surgery (EFAS) score and 12-item Short Form Survey (SF-12) were also documented.

RESULTS

A total of 57 patients were included, of which 20 (35.1%) had a sural nerve injury. Five patients had a neurapraxia (8.8%), while 15 patients had a permanent injury (26.3%). Respecting the "safe incision" decreased sural nerve injury (p = 0.02). The type of osteotomy and closure was not significant. No significant differences were found in the functional tests between the different techniques, or between patients who presented sural nerve injury and those who did not.

CONCLUSION

Sural nerve injury after calcaneal sliding osteotomies is higher than previously reported in the scientific literature, with an incidence of 35.1% (20/57 patients). Respecting the so-called safe zone (oblique incision that runs through the point that is > 1/3 of the distance from the tip of the lateral malleolus to the posteroinferior margin of the calcaneus) clearly decreases the incidence of sural nerve injury. Finally, the majority of patients remained asymptomatic despite the neurological injury.

The incision strategy for minimizing sural nerve injury in medial displacement calcaneal osteotomy: a cadaveric study

Background

The skin incision for medial displacement calcaneal osteotomy (MDCO) often damages the sural nerve. We aimed to identify the practical reference area in which the surgeon can incise the skin to minimize the injury of the sural nerve during MDCO.

Methods

The foot and ankles of 20 cadavers were dissected. The landmarks were the following four anatomical references: point A, the tip of the lateral malleolus; point B, the inferior margin of the calcaneus on the vertical line through point A; point C, the posteroinferior apex of the calcaneus; and point D, the lateral border of the Achilles tendon on the horizontal line through point A. The distances from the sural nerve to points A and B in the vertical direction (lines D1 and D2, respectively), to points A and C in the diagonal direction (lines D3 and D4, respectively), and to points A and D in the horizontal direction (lines D5 and D6, respectively) were measured.

Results

The median ratios of D1 to D1+D2, D3 to D3+D4, and D5 to D5+D6 were 0.34 (range 0.25 to 0.45), 0.23 (range 0.16 to 0.33), and 0.38 (range 0.26 to 0.50), respectively.

Conclusions

The distance ratios according to easily identifiable references would be a more practical incision strategy for surgeons to minimize sural nerve injury in both open and minimally invasive/percutaneous MDCO.

Calcaneal Osteotomy Safe Zone to Prevent Neurological Damage: Fact or Fiction?

BACKGROUND

Calcaneal osteotomy is a commonly used surgical option for the correction of hindfoot malalignment. A previous cadaveric study described a neurological "safe zone" for calcaneal osteotomy. We performed a retrospective chart review to evaluate the presence of neurological injuries following calcaneal osteotomies and the location of the osteotomy in relation to the reported safe zone.

METHODS

In this retrospective study, we reviewed charts of patients who underwent calcaneal osteotomy at our institution from 2011 to 2015. All immediate postoperative radiographs were examined and the shortest distance between the calcaneal osteotomy line and a reference line connecting the posterior superior apex of the calcaneal tuberosity to the origin of the plantar fascia was measured. If the osteotomy line was positioned within an area 11.2 mm anterior to the reference line, it was considered to be inside the neurological safe zone. We correlated the positioning of the osteotomy with the presence of postoperative neurological complications.

RESULTS

We identified 179 calcaneal osteotomy cases. Of the 174 (97.2%) nerve injury-free cases, 62.6% (109/174) were performed inside the defined "safe zone" while 37.4% (65/174) outside. A total of 5 (2.8%) nerve complications were identified: 3 (60%) were inside the safe zone and 2 (40%) outside the safe zone. Osteotomies outside the safe zone had a 1.114 relative risk of nerve injury with a 95% CI of 0.191 to 6.500 and showed no statistically significant difference ( P = .9042).

CONCLUSION

Our findings suggest that the clinical "safe zone" in calcaneal osteotomies may not actually exist, likely because of wide anatomical variation of the implicated nerves, as described in prior studies. Patients should be properly counseled preoperatively on the low, but seemingly fixed, risk of nerve injury before undergoing calcaneal osteotomy.

LEVELS OF EVIDENCE

Level III: Retrospective comparative study.

Adult-Acquired Flatfoot Deformity

Adult-acquired flatfoot deformity (AAFD) comprises a wide spectrum of ligament and tendon failure that may result in significant deformity and disability. It is often associated with posterior tibial tendon deficiency (PTTD), which has been linked to multiple demographic factors, medical comorbidities, and genetic processes. AAFD is classified using stages I through IV. Nonoperative treatment modalities should always be attempted first and often provide resolution in stages I and II. Stage II, consisting of a wide range of flexible deformities, is typically treated operatively with a combination of soft tissue procedures and osteotomies. Stage III, which is characterized by a rigid flatfoot, typically warrants triple arthrodesis. Stage IV, where the flatfoot deformity involves the ankle joint, is treated with ankle arthrodesis or ankle arthroplasty with or without deltoid ligament reconstruction along with procedures to restore alignment of the foot. There is limited evidence as to the optimal procedure; thus, the surgical indications and techniques continue to be researched.

Double calcaneal osteotomy with minimally invasive surgery for the treatment of severe flexible flatfeet

BACKGROUND

Severe flexible flatfoot deformity in children and adolescents is a complex problem. Calcaneal lengthening remains the gold standard for surgical correction at this institution. However, in a minority of patients, inadequate correction of valgus is noted at surgery and a further calcaneal shift osteotomy is done.

METHODS

We have conducted a retrospective review of ten patients who received 15 combined minimally invasive calcaneal shift and calcaneal lengthening osteotomies, which were all performed by the senior author. All patients had failed conservative treatment. We describe our technique for double calcaneal osteotomy combining minimally invasive surgery (MIS) for the medial calcaneal shift with traditional open calcaneal lengthening osteotomy for treating children and adolescents with severe flexible flatfoot deformity.

RESULTS

The average shift achieved was 8.07 mm. The average improvement in Meary's angle was 14.99°. All of them had radiological and clinical union at 12 weeks. None of the patients developed sural nerve injury, wound breakdown, or infection of the MIS incision.

CONCLUSION

In double calcaneal osteotomies, the MIS calcaneal medial shift technique can be used safely with potentially lower risks of wound complications and sufficient medial shift, compared to conventional open extensive surgery.

IMPLICATIONS

MIS calcaneal shift osteotomy has an advantage over open conventional open technique in cases where the skin is under tension like in combined calcaneal lengthening osteotomy. With experience, the procedure can be faster than an open procedure.

[Dwyer osteotomy : Lateral sliding osteotomy of calcaneus]

OBJECTIVE

To correct the underlying inframalleolar varus deformity and to restore physiologic biomechanics of the hindfoot.

INDICATIONS

Neurologic, posttraumatic, congenital, and idiopathic cavovarus deformity. In patients with end-stage ankle osteoarthritis with varus heel malposition as additional single-stage procedure complementing total ankle replacement. Severe peroneal tendinopathy with concomitant cavovarus deformity.

CONTRAINDICATIONS

General surgical or anesthesiological risks, infections, critical soft tissue conditions, nonmanageable hindfoot instability, neurovascular impairment of the lower extremity, neuroarthropathy (e. g., Charcot arthropathy), end-stage osteoarthritis of the subtalar joint, severely reduced bone quality, high age, insulin-dependent diabetes mellitus, smoking.

SURGICAL TECHNIQUE

The lateral calcaneus cortex is exposed using a lateral incision. The osteotomy is performed through an oscillating saw. The posterior osteotomy fragment is manually mobilized and shifted laterally. If needed, a laterally based wedge can be removed and/or the osteotomy fragment can be translated cranially. The osteotomy is stabilized with two cannulated screws, followed by wound closure.

POSTOPERATIVE MANAGEMENT

A soft wound dressing is used. Thromboprophylaxis is recommended. Patient mobilization starts on postoperative day 1 with 15 kg partial weight bearing using a stabilizing walking boot or cast for 6 weeks. Following clinical and radiographic follow-up at 6 weeks, full weight bearing is initiated step by step.

RESULTS

Between January 2009 and June 2013, a Dwyer osteotomy was performed in 31 patients with a mean age of 45.7 ± 16.3 years (range 21.5-77.4 years). All patients had a substantial inframalleolar cavovarus deformity with preoperative moment arm of the calcaneus of -17.9 ± 3.3 mm (range -22.5 to -10.5 mm), which has been improved significantly to 1.6 ± 5.9 mm (range -16.9 to 9.9 mm). Significant pain relief from 6.3 ± 1.9 (range 4-10) to 1.1 ± 1.1 (range 0-4) using the visual analogue scale was observed. The American Orthopaedic Foot and Ankle Society score significantly improved from 33.1 ± 14.2 (range 10-60) to 78.0 ± 10.5 (range 55-95).