Tibial nerve palsy associated with lateralizing calcaneal osteotomy: case reviews and technical tip

Feasibility and safety of minimally invasive calcaneal osteotomy (MICO) through a medial approach: a case-control study

INTRODUCTION

Minimally invasive calcaneal osteotomy (MICO) is already an established surgical procedure for correcting hindfoot deformities using a lateral approach. So far, no description of a medial approach for MICO has been published.

MATERIAL AND METHODS

Between August 2022 and March 2023, 32 consecutive patients (MICO with medial approach, MMICO: n = 15; MICO with lateral approach, LMICO: n = 17) underwent MICO as part of complex reconstructive surgery of the foot and ankle with concomitant procedures. The amount of correction in the axial view of the calcaneus and consolidation rates were evaluated radiographically. Subjective satisfaction, stiffness of the subtalar joint, and pain level (numeric rating scale, NRS) at the level of the heel were assessed clinically. The last follow-up was at 6 months.

RESULTS

All osteotomies consolidated within 6 months after surgery. Displacement of the tuber was 9 mm on average in either group. Relevant subtalar joint stiffness was detected in 5 MMICO and 6 LMICO patients. No relevant differences between the groups were detected for wound healing problems, nerve damage, heel pain or patient satisfaction.

CONCLUSION

In this study lateral and medial approaches for MICO were performed. Similar degrees of correction and low complication rates were found in both groups. The medial approach for MICO is safe and can be beneficial regarding patient positioning and arrangement of the C‑arm.

Examination of Safe Zone to Avoid Injury of the Lateral Plantar Artery During Calcaneal Osteotomy: A Fresh Cadaveric Study

BACKGROUND

Calcaneal osteotomy are used to treat various pathologies in the correction of hindfoot deformities. But lateral plantar artery (LPA) pseudoaneurysms have been reported following calcaneal osteotomy, and LPA pseudoaneurysms may be at risk for rupture. Although the vascular structures in close proximity to calcaneal osteotomies have variable courses and branching patterns, there is little information on safe zone for LPA during calcaneal osteotomy. The aims of this study were to identify the safety zone to avoid the LPA injury during calcaneal osteotomy.

METHODS

Enhanced computed tomography scans of 25 fresh cadaveric feet (male, n = 13; female, n = 12; mean age 79.0 years at the time of death) were assessed. The specimens were injected with barium via the external iliac artery. Line A is the landmark line and extends from the posterosuperior aspect of the calcaneal tuberosity to the plantar fascia origin, and the perpendicular distance between the LPA and line A at its closest point was measured on sagittal images.

RESULTS

The average perpendicular distance between the LPA and line A at its closest point was 15.2 ± 2.9 mm. In 2 cases (8.0 %), the perpendicular distance between the LPA and line A at its closest point was very close, approximately 9 mm. In 18 of 25 feet (72.0%), the point where perpendicular distance from the line A to LPA is the closest was the bifurcation of one of the medial calcaneal branches from LPA, and in 7 feet in 25 feet (28.0%) feet the point where perpendicular distance from the line A to LPA is the closest was the trifurcation of LPA, medial plantar artery, and one of the medial calcaneal branches.

CONCLUSIONS

Calcaneal osteotomy approximately more than 9 mm from the line A could injure the LPA in overpenetration into the medial aspect of tcalcaneal osteotomy. Completion of the osteotomy on the medial side should be performed with caution to avoid iatrogenic injury of the LPA.

LEVELS OF EVIDENCE:

Level IV, Cadaveric study.

Joint Preservation Strategies for Managing Varus Ankle Deformities

Joint preserving strategies have evolved to a successful treatment option in early and midstage medial ankle OA caused by varus deformity. Though talar tilt can often not be fully corrected, it provides substantial postoperative pain relief, functional improvement, and slowing of the degenerative process. Osseous balancing with osteotomies is the main step for restoration of ankle mechanics and normalization of joint load. Overall, the key for success is to understand the underlying causes that have contributed to the varus OA in each case, and to use all treatment modalities necessary to restore appropriate alignment of the hindfoot complex.

Calcaneal osteotomy for hindfoot deformity

Calcaneal osteotomy is an extra-articular procedure used for conservative surgical treatment of hindfoot deformity. It has static, architectural and dynamic effects, reorienting the tuberosity action point of the digastric muscle formation of the sural triceps and plantar aponeurosis. Calcaneal osteotomies vary in location, form and displacement, but can be categorized as tuberosity osteotomy, acting on talar position, and cervical osteotomy, acting on Chopart joint-line orientation. We here describe the 3 main calcaneal osteotomies we use for hindfoot deformity: talar varus/valgus, valgus flatfoot, and midfoot abductus/adductus. In each case, we describe our technique, resulting from our responses to the difficulties we have had to deal with: medializing osteotomy: performed percutaneously to limit skin complications, and easily associated to cervical calcaneal osteotomy to manage valgus flatfoot; Hintermann cervical adduction osteotomy: providing excellent angular correction, while conserving a medial cortical hinge; lateralizingosteotomy: performed on a medial approach, to enhance translation capacity and prevent the acute tarsal tunnel syndrome with which we have been otherwise confronted. Correcting foot deformities involves complex, multi-dimensional, multi-tissue surgery that is risky as it concerns a segment with terminal vascularization. The present three techniques need to be mastered, as they are usually associated to other tendon and/or ligament reconstruction procedures, and tourniquet time is limited. LEVEL OF EVIDENCE: V; expert opinion.

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.

Effect of Lateral Sliding Calcaneus Osteotomy on Tarsal Tunnel Pressure

Background:

Lateral sliding calcaneus osteotomies are common procedures to correct hindfoot varus deformities. Shifting the calcaneal tuberosity laterally (lateralization) can lead to tarsal tunnel pressure increase and tibial nerve palsy. The purpose of this cadaveric biomechanical study was to investigate the correlation of lateralization and pressure increase underneath the flexor retinaculum.

Methods:

The pressure in the tarsal tunnel of 12 Thiel-fixated human cadaveric lower legs was measured in different foot positions and varying degrees of calcaneal lateralization.

Results:

The mean pressure increased from plantarflexion (PF) to neutral position (NP) and from NP to hindfoot dorsiflexion (DF), and with increasing amounts of lateralization of the calcaneal tuberosity. The mean baseline pressure in PF was 1.5, in NP 2.2, and in DF 6.5 mmHg and increased to 8.1 in PF, 18.4 in NP, and 33.1 mmHg with 12 mm of lateralization. The release of the flexor retinaculum significantly lowered the pressure.

Conclusion:

Increasing pressures were found in the tarsal tunnel with increasing lateralization of the tuberosity and with both dorsiflexion and plantarflexion of the ankle.

Clinical Relevance:

A pre-emptive release of the flexor retinaculum for a lateralization of the calcaneal tuberosity of more than 8 mm should be considered, especially if specific patient risk factors are present. No tibial nerve palsy should be expected with 4 mm of lateralization.

Medial Soft-Tissue Release for Lateralising Calcaneal Osteotomy: A Cadaveric Study

BACKGROUND

Lateralising calcaneal osteotomy for pes cavus is generally regarded to be harder to shift than a medialising calcaneal osteotomy for pes planus. The aim of our study was to determine the structures which restrain a lateral shift.

METHODS

Lateralising calcaneal osteotomy was performed on four soft-embalmed cadavers via a standard lateral approach and the lateral calcaneal shift was measured before and after the release of flexor retinaculum. Further exploratory dissection around the osteotomy site revealed the abductor hallucis muscle to be the main restraint to the lateral shift of the calcaneus. Subsequently, lateralising calcaneal osteotomy was performed on another four cadavers and the abductor hallucis muscle fascia as well as the plantar fascia was released. The lateral shift was measured before and after the fascia release, and compared with the results achieved following the flexor retinaculum release in the first four cadavers.

RESULTS

Lateralising calcaneal osteotomy alone resulted in an average of 4.5-mm lateral shift in the first four cadaveric specimens. Releasing the flexor retinaculum led to a further 3-mm increase of lateral shift on average. In the next four cadaveric specimens, lateralising calcaneal osteotomy alone resulted in an average of 5.5-mm lateral shift. Release of abductor hallucis muscle fascia and the plantar fascia in these four specimens increased the lateral shift by an additional 7 mm on average. Hence, release of abductor hallucis muscle fascia resulted in an extra 4-mm shift on average compared with what is achieved with flexor retinaculum release.

CONCLUSIONS

Abductor hallucis muscle fascia was discovered to be one of the main structures limiting the lateral shift in lateralising calcaneal osteotomy. Release of fascia over this muscle as well as the plantar fascia should help in improving lateral shift. Further experimental and clinical research is necessary to confirm the findings of this pilot study.

Tibial Nerve Palsy After Lateralizing Calcaneal Osteotomy

Background: Lateralizing calcaneal osteotomy (LCO) is a common procedure used to correct hindfoot varus. Several complications have been described in the literature, but only a few articles describe tibial nerve palsy after this procedure. Our hypothesis was that tibial nerve palsy is a common complication after LCO. Methods: A retrospective study of patients undergoing LCO for hindfoot varus between 2007 and 2013 was performed. A total of 15 patients (18 feet) were included in the study. The patients were examined for tibial nerve deficit, and all the patients were examined with a computed tomography (CT) scan of both feet. Patients with a preexisting neurological disease were excluded. The primary outcome was tibial nerve palsy, and the secondary outcomes were reduction of the tarsal tunnel volume, the distance from subtalar joint to the osteotomy, and the lateral step at the osteotomy evaluated by CT scans. Results: Three of the 18 feet examined had tibial nerve palsy at a mean follow-up of 51 months. The mean reduction in tarsal tunnel volume when comparing the contralateral nonoperated foot to the foot operated with LCO was 2732 mm³ in the group without neurological deficit and 2152 mm³ in the group with neurological deficit (P = .60). Conclusion: 3 of 18 feet had tibial palsy as a complication to LCO. We were not able to show that a larger decrease in the tarsal tunnel volume, a more anterior calcaneal osteotomy, or a larger lateral shift of the osteotomy is associated with tibial nerve palsy. Levels of Evidence: Level IV: Retrospective case series.

Two-Stage Varus Correction

Coronal plane deformity following total ankle arthroplasty has been associated with poor clinical outcomes and early prosthesis failure. Neutral mechanical alignment and prosthetic joint stability must be achieved through meticulous surgical planning and precise technical execution. Cavovarus foot deformity and varus malalignment of the lower extremity is reviewed, with particular emphasis as it relates to total ankle arthroplasty. Correction of varus malalignment may be performed at the time of total ankle arthroplasty or as a 2-stage procedure. Surgeon experience, revision total ankle arthroplasty, and subtalar arthrodesis should be considerations when contemplating 2-stage varus correction.

Inframalleolar Varus Deformity: Role of Calcaneal Osteotomies

The cavo varus foot is a complex pathology due to skeletal deformity and neuro-muscular unbalance. The key concept for a successful treatment is to consider the whole foot and ankle complex from a bone and soft tissue perspective. Undercorrection is the main issue in cavo varus foot management, which may be attributed to intrinsic correction defects of the described calcaneal osteotomies or to a lack of understanding about the pathology and the subsequent algorithm of treatment. The authors disclose their daily algorithm of treatment, considering the foot and ankle complex and the role of calcaneal osteotomies in ankle inframalleolar deformities.

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.

Plantar Fascia Release Through a Single Lateral Incision in the Operative Management of a Cavovarus Foot: A Cadaver Model Analysis of the Operative Technique

Plantar fascia release and calcaneal slide osteotomy are often components of the surgical management for cavovarus deformities of the foot. In this setting, plantar fascia release has traditionally been performed through an incision over the medial calcaneal tuberosity, and the calcaneal osteotomy through a lateral incision. Two separate incisions can potentially increase the operative time and morbidity. The purpose of the present study was threefold: to describe the operative technique, use cadaveric dissection to analyze whether a full release of the plantar fascia was possible through the lateral incision, and examine the proximity of the medial neurovascular structures to both the plantar fascia release and calcaneal slide osteotomy when performed together. In our cadaveric dissections, we found that full release of the plantar fascia is possible through the lateral incision with no obvious damage to the medial neurovascular structures. We also found that the calcaneal branch of the tibial nerve reliably crossed the osteotomy in all specimens. We have concluded that both the plantar fascia release and the calcaneal osteotomy can be safely performed through a lateral incision, if care is taken when completing the calcaneal osteotomy to ensure that the medial neurovascular structures remain uninjured.

Lateralizing Calcaneal Osteotomies and Their Effect on Calcaneal Alignment: A Three-Dimensional Digital Model Analysis

BACKGROUND

Few authors have directly compared multiple types of lateralizing calcaneal osteotomies (LCOs) in terms of their ability to achieve deformity correction. The aim of this research was to use a digital model of a varus hindfoot to compare 4 different LCOs in terms of deformity correction and amount of tuberosity lateralization required. The authors hypothesis was that osteotomies involving a wedge resection would achieve greater correction with less lateralization.

METHODS

A weightbearing computed tomographic scan of a patient with a varus hindfoot deformity was used to construct a 3-dimensional digital model of the hindfoot, preserving weightbearing alignment. Four different LCOs were modeled: a standard oblique osteotomy, a Dwyer osteotomy, a modified Dwyer osteotomy involving lateralization in addition to wedge resection, and a Malerba Z-type osteotomy with wedge resection and lateralization. Incremental corrections were performed with each osteotomy type, and amount of correction was assessed with a vertical hindfoot angle and measurement of the lateral translation of the most inferior aspect of the calcaneus. Calcaneal length and osteotomy contact surface area were also measured.

RESULTS

The modified Dwyer osteotomy led to the greatest improvements in the vertical hindfoot angle and lateral translation, followed by the Malerba osteotomy. The standard and Malerba osteotomies allowed the most preservation of calcaneal length; the Malerba and Dwyer osteotomies had the greatest contact surface area.

CONCLUSION

LCOs that involve wedge resection as well as lateralization were able to achieve the greatest correction of hindfoot varus.

CLINICAL RELEVANCE

For the surgical treatment of cavovarus foot deformities, osteotomies with wedge resection in addition to lateralization enable more powerful correction.

Minimal Incision/Minimally Invasive Medializing Displacement Calcaneal Osteotomy

Minimally invasive techniques are readily applicable to calcaneal osteotomies and have the potential to accomplish hindfoot correction equivalent to open procedures with less morbidity and pain. Use of a guidance jig makes the procedure more predictable. While most anatomic features of the procedure are the same as those with open techniques, special care must be taken to avoid neurovascular injury because there is no open exposure. Anatomic guidelines have been established for appropriately localizing the osteotomy.

LEVEL OF EVIDENCE

Level V, expert opinion.

Rate of Neurologic Injury Following Lateralizing Calcaneal Osteotomy Performed Through a Medial Approach

BACKGROUND

Calcaneal osteotomies are commonly used to correct varus hindfoot alignment in patients with symptomatic cavovarus deformity. Translational, closing wedge, and Malerba-type osteotomies have been implicated in the development of tarsal tunnel syndrome and neurologic injury to branches of the tibial nerve. The authors hypothesized that there would be minimal clinically important injury to the tibial nerve by performing a translational calcaneal osteotomy from a medial approach.

METHODS

All patients undergoing a cavovarus reconstruction by a single surgeon were identified. Patients were included if they underwent a lateralizing calcaneal osteotomy via medial approach. Demographics, operative reports, and clinic notes were reviewed to identify concomitant procedures performed, incidence of postoperative tarsal tunnel syndrome, complications, and preoperative and postoperative nerve examinations. Postoperative radiographs were reviewed for location of the osteotomy relative to the posterior tubercle.

RESULTS

Twenty-four patients underwent lateralizing calcaneal osteotomy via a medial approach. Of the osteotomies, 83.3% (20/24) were in the middle third of the calcaneus, with a mean of 11.6-mm translation. No patients developed postoperative tarsal tunnel syndrome or tibial nerve palsy.

CONCLUSION

Lateralizing calcaneal osteotomy performed via a medial approach had a clinically negligible incidence of neurologic injury. Adequate translation was achieved to obtain correction of varus hindfoot deformity. The authors believe that there is less direct and less percussive injury to branches of the tibial nerve when performing the osteotomy from medial to lateral. This technique may represent an operative strategy to minimize risk to the tibial nerve and reduce neurologic deficit following cavovarus reconstruction.

LEVEL OF EVIDENCE

Level IV, case series.

Overcorrected Flatfoot Reconstruction

The overcorrected flatfoot reconstruction is a less common but often difficult sequelae of surgical treatment of the adult acquired flatfoot deformity. Understanding the patient's symptoms and how they correlate to the procedures performed during the index surgery are paramount to determining the appropriate course of treatment. Patients' symptoms may resemble those seen in the cavovarus foot condition, often secondary to overlengthening of the lateral column or excessive displacement of the calcaneal tuberosity. Osteotomies of the calcaneus, midfoot, and often the first metatarsal may be sufficient to revise the overcorrection. However, hindfoot and/or midfoot arthrodesis may be required in more severe or rigid cases.

Neurologic Deficit Associated With Lateralizing Calcaneal Osteotomy for Cavovarus Foot Correction

BACKGROUND

Lateralizing calcaneal osteotomy (LCO) is a frequently used technique to correct hindfoot varus deformity. Tibial nerve palsy following this osteotomy has been described in case reports but the incidence has not been quantified.

METHODS

Eighty feet in 72 patients with cavovarus foot deformity were treated over a 6-year span by 2 surgeons at their respective institutions. Variations of the LCO were employed for correction per surgeon choice. A retrospective chart review analyzed osteotomy type, osteotomy location, amount of translation, and addition of a tarsal tunnel release in relation to the presence of any postoperative tibial nerve palsy. Tibial nerve branches affected and the time to resolution of any deficits was also noted.

RESULTS

The incidence of neurologic deficit following LCO was 34%. With an average follow-up of 19 months, a majority (59%) resolved fully at an average of 3 months. There was a correlation between the development of neurologic deficit and the location of the osteotomy in the middle third as compared to the posterior third of the calcaneal tuber. We found no relationship between the osteotomy type, amount of correction, or addition of a tarsal tunnel release and the incidence of neurologic injury.

CONCLUSIONS

Tibial nerve palsy was not uncommon following LCO. Despite the fact that deficits were found to be transient, physicians should be more aware of this potential problem and counsel patients accordingly. To decrease the risk of this complication, we advocate extra caution when performing the osteotomy in the middle one-third of the calcaneal tuberosity. Although intuitively the addition of a tarsal tunnel release may protect against injury, no protective effect was demonstrated in this retrospective study.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Effects on the Tarsal Tunnel Following Malerba Z-type Osteotomy Compared to Standard Lateralizing Calcaneal Osteotomy

BACKGROUND

Tarsal tunnel syndrome is a known complication of lateralizing calcaneal osteotomy. A Malerba Z-type osteotomy may preserve more tarsal tunnel volume (TTV) and decrease risk of neurovascular injury. We investigated 2 effects on the tarsal tunnel of the Malerba osteotomy compared to a standard lateralizing osteotomy using a cadaveric model: (1) the effect on TTV as measured by magnetic resonance imaging (MRI) and (2) the proximity of the osteotomy saw cuts to the tibial nerve.

METHODS

Ten above-knee paired cadaveric specimens underwent MRI of the ankle to obtain a baseline measurement of TTV. One foot in each pair received a standard lateralizing calcaneal osteotomy, with the other foot receiving a Malerba osteotomy. MRIs were performed after each of 3 increasing amounts of lateral displacement, which were accompanied by increasing amounts of wedge resection in the Malerba osteotomy group. TTV was measured on MRI using previously described and validated parameters. Differences in TTV with osteotomy type, displacement, and their interaction were assessed with generalized estimating equations. After all MRIs were completed, each specimen was dissected and the nearest distance of tibial nerve branches to the osteotomy site was measured.

RESULTS

Baseline TTV averaged 13 229 ± 2354 mm(3) and did not differ between groups (P = .386). TTV decreased on average by 7% after the first translation, 14% after the second, and 27% after the third (P < .005 for each). The magnitude of the decrease in TTV did not differ between those specimens with standard osteotomies versus those with Malerba osteotomies (P = .578). At least one of the major branches of the tibial nerve crossed the osteotomy site in 5 of 5 specimens that received the Malerba osteotomy versus 2 of 5 that received a standard osteotomy.

CONCLUSION

Regardless of osteotomy type, lateralizing calcaneal osteotomy decreased TTV. In all specimens, the osteotomy was at the level of branches of the tibial nerve.

CLINICAL RELEVANCE

Our results demonstrate that lateralizing calcaneal osteotomies must be performed with care to avoid excessive lateral translation as well as direct nerve injury on the nonvisualized medial side of the calcaneus.

Minimally Invasive Calcaneal Osteotomy: Does the Shannon Burr Endanger the Neurovascular Structures? A Cadaveric Study

Calcaneal osteotomies are used to correct hindfoot alignment. Traditional open procedures have been plagued with complications. Various minimally invasive techniques have been described but are laborious and time-consuming. A percutaneous technique using a side cutting "Shannon" burr offers a simple and reliable alternative; however, little evidence is available to address the safety concerns. The aim of the present study was to quantify the risk posed to the medial and lateral neurovascular structures using this technique. The study was performed at the anatomy department, University of Sussex, using 13 fresh-frozen, below-the-knee cadaveric specimens during a training session held by WG Healthcare UK, Ltd. (Letchworth, Herts). The participants were 11 consultant orthopedic surgeons, who were inexperienced in minimally invasive surgery, and 2 demonstrators. Each performed a chevron calcaneal osteotomy using a Shannon burr by way of a lateral percutaneous approach under fluoroscopic guidance. The authors subsequently dissected the specimens to identify the neurovascular structures, describe their anatomic relations and proximity to the burr, and note any damage incurred. No evidence was found of significant neurovascular injury. Two very small proximal branches of the sural nerve were transected, the nerve itself passing safely 9 to 21 mm anterosuperior to the entry point. The medial neurovascular bundle crossed the path of the osteotomy in 4 specimens but was protected by the medial head of the quadratus plantae muscle. In conclusion, the Shannon burr for calcaneal osteotomy has the potential to minimize the surgical morbidity and maximize surgical efficiency without compromising safety in all patients with normal anatomy of the quadratus plantae muscle.

[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).

A case of acute tarsal tunnel syndrome following lateralizing calcaneal osteotomy

Surgical correction of hindfoot varus is frequently performed with a lateral displacement calcaneal osteotomy. It has rarely been associated with iatrogenic tarsal tunnel syndrome in patients with pre-existing neurological disease. We report the first case of acute postoperative tarsal tunnel syndrome in a neurologically intact patient with post-traumatic hindfoot varus. Early diagnosis and emergent operative release afforded an excellent clinical outcome. Imaging studies can help outrule a compressive hematoma and assess for possible nerve transection; however it is paramount that a high index of suspicion is utilized with judicious operative intervention to minimize long-term sequelae.

Hindfoot deformity and calcaneal tuberosity osteotomies

Calcaneal tuberosity osteotomies are commonly used to treat coronal plane deformities of the hindfoot. Assessing hindfoot alignment can be difficult and there is little evidence to guide the physician when considering the surgical treatment of these deformities. The indications for a calcaneal osteotomy are unclear in the literature because most of the published studies supporting their use are confounded by concurrent procedures such as in adult-acquired flatfoot correction or cavovarus reconstruction. For the same reason, the biomechanical consequences, long-term effects, and performance in vivo are largely unknown.

LEVEL OF EVIDENCE

Expert opinion, Level V.

The effect of medial and lateral calcaneal osteotomies on the tarsal tunnel

BACKGROUND

As an entrapment phenomenon, tarsal tunnel syndrome has been described after calcaneal osteotomy, and since the tibial nerve has also been shown to be very sensitive to ankle position, position of the calcaneus after osteotomy and displacement was thought to likely influence the environment of the tibial nerve within the tarsal canal. The respective volume of the tarsal canal was therefore hypothesized to decrease with medial or lateral displacement osteotomies of the calcaneus.

METHODS

Anterior and posterior calcaneal osteotomies were made in cadaveric matched pairs and brought through sequential medial and lateral displacements. Magnetic resonance imaging was used to estimate the comparative resultant volume of the tarsal canal after each of these new positions were assumed, as compared with baseline. The proximity of the osteotomy cut to the nerve's location was also measured.

RESULTS

The tarsal tunnel volume was calculated for all 5 displacement states and were as follows: far-lateral (9506 mm(3)), near-lateral (10 073 mm(3)), normal (11 839 mm(3)), near-medial (11 489 mm(3)), and far-medial (11 760 mm(3)). No significant difference in tarsal tunnel volume was identified between the normal, nondisplaced specimens in the anterior or posterior groups (11 954 mm(3) vs 11 809 mm(3)). No difference in tarsal tunnel volume was identified between the anterior and posterior osteotomies at any of the 4 displacements. The distance from tibial nerve to the medial exit site of the osteotomy was found to be significantly less in the anterior group compared to the posterior group (4 mm vs 14.2 mm, P < .0001).

CONCLUSION

Lateral, but not medial, osteotomy fragment displacement results in significant reduction of tarsal tunnel volume. The location of the cut does not seem to affect any substantive change in volume. Anteriorly placed osteotomies appear to jeopardize the neurovascular structures more than posteriorly placed osteotomies.

CLINICAL RELEVANCE

These findings provide surgeons with clinical evidence in support of performing a prophylactic tarsal tunnel release for patients undergoing lateralizing calcaneal osteotomies.

Geometry of the lateral sliding, closing wedge calcaneal osteotomy: review of the two methods and technical tip to minimize shortening

BACKGROUND

A lateral closing wedge osteotomy is used for correction of varus hindfoot deformities. Since its original description, different techniques and geometries of the calcaneal bone wedge resection have been described. Even though the techniques seem similar, very different final bone architectures result from each technique, the effects of which are not known. This paper explores several of these techniques and the implications in deformity correction as well as the secondary effects of calcaneal shortening.

METHODS

Mathematical and geometric analysis is performed in 2-dimensions for several hypothetical calcaneal osteotomies as described by the original authors. The resulting changes are calculated and compared.

RESULTS

The shape of the bone resection for the lateral closing wedge osteotomy does not result in significantly different final calcaneal architectures. Both techniques studied result in the same amount of calcaneal shortening and deformity correction. However, when lateral calcaneal wedge resection is combined with lateral translation of the tuberosity for additional deformity correction, more calcaneal shortening is seen with posteriorly directed osteotomies than those that are transverse.

CONCLUSION

The lateral closing wedge osteotomy of the calcaneus results in correction of varus hindfoot deformity at the expense of some calcaneal shortening. Lateral translation of the tuberosity may result in additional calcaneal. The clinical effects of calcaneal shortening or medial soft tissue or nerve tethering from these different techniques are unknown and deserve further investigation.

LEVEL OF EVIDENCE

Level V, expert opinion.

What is the role and limit of calcaneal osteotomy in the cavovarus foot?

Calcaneal osteotomy is a commonly used tool in cavovarus foot reconstructions. Understanding the indications and limitations of such an osteotomy is critical to success in reconstruction. We present a comprehensive review of surgical calcaneal osteotomy techniques and the currently available state of literature for their indications and limitations.

Calcaneal osteotomy in the treatment of adult acquired flatfoot deformity

Calcaneal osteotomies are an essential part of our current armamentarium in the treatment of AAFD. Soft tissue correction or bony realignment alone have failed to adequately correct the deformity; therefore, both procedures are used simultaneously to achieve long-term correction. Medial displacement and lateral column lengthening osteotomies in isolation or in combination and the Malerba osteotomy have been employed along with soft tissue balancing to good effect by various authors. The goal is to create a stable bony configuration with adequate soft tissue balance to maintain dynamic equilibrium in the hindfoot. In “pronatory syndromes,” the relation of the osteotomy to the posterior subtalar facet modifies the biomechanics of the hindfoot in different ways. Anterior calcaneal osteotomies correct deformities in the transverse plane (forefoot abduction), whereas posterior tuberosity osteotomies result in “varization” of the calcaneus and correct the frontal plane deformity. The choice of osteotomy depends on the plane of the dominant deformity. If the subtalar axis is more horizontal than normal, transverse plane movement is cancelled out and the frontal plane eversion–inversion is predominant. The patient presents with marked hindfoot valgus without significant forefoot abduction. Conversely, if the subtalar axis is more vertical than normal, transverse plane movement is predominant and the patient presents with forefoot abduction and instability of the medial midtarsal joints, although without significant hindfoot valgus. In this situation, a lateral column lengthening procedure is recommended to decrease the uncovering of the talar head and improve the height of the arch while correcting the forefoot abduction. With a predominant frontal plane deformity, medialization of the calcaneal tuberosity is used to displace the calcaneal weight bearing axis medially, aligning it with the tibial axis and restoring the function of the gastrosoleus as a heel invertor. An essential prerequisite for this is the absence of arthritis affecting the subtalar joint. The Achilles tendon may need to be lengthened at the same time.

Postoperative complications of posterior ankle and hindfoot arthroscopy

BACKGROUND

Posterior ankle and hindfoot arthroscopy, performed with use of posteromedial and posterolateral portals with the patient in the prone position, has been utilized for the treatment of various disorders. However, there is limited literature addressing the postoperative complications of this procedure. In this study, the postoperative complications in patients treated with posterior ankle and hindfoot arthroscopy were analyzed to determine the type, rate, and severity of complications.

METHODS

The study included 189 ankles in 186 patients (eighty-two male and 104 female; mean age, 37.1 ± 16.4 years). The minimum duration of follow-up was six months, and the mean was 17 ± 13 months. The most common preoperative intra-articular diagnoses were subtalar osteoarthritis (forty-six ankles), an osteochondral lesion of the talus (forty-two), posterior ankle impingement (thirty-four), ankle osteoarthritis (twenty), and subtalar coalition (five). The most common extra-articular diagnoses were painful os trigonum (forty-six), flexor hallucis longus tendinitis (thirty-two), and insertional Achilles tendinitis (five).

RESULTS

The most common intra-articular procedures were osteochondral lesion debridement (forty-four ankles), subtalar debridement (thirty-eight), subtalar fusion (thirty-three), ankle debridement (thirty), and partial talectomy (nine). The most common extra-articular procedures were os trigonum excision (forty-eight), tenolysis of the flexor hallucis longus tendon (thirty-eight), and endoscopic partial calcanectomy (five). Complications were noted following sixteen procedures (8.5%); four patients had plantar numbness, three had sural nerve dysesthesia, four had Achilles tendon tightness, two had complex regional pain syndrome, two had an infection, and one had a cyst at the posteromedial portal. One case of plantar numbness and one case of sural nerve dysesthesia failed to resolve.

CONCLUSIONS

Our experience demonstrated that posterior ankle and hindfoot arthroscopy can be performed with a low rate of major postoperative complications.

Hindfoot varus and neurologic disorders

Muscle imbalance from numerous underlying neurologic disorders can cause dynamic and static hindfoot varus deformity. Most etiologies are congenital, and therefore affect bone morphology and the shape of the foot during growth. Weak and strong muscle groups, bone deformity, and soft-tissue contractures have to be carefully assessed and considered for successful management. Because of the variety of the etiologies and the differences in presentation, treatment decisions in varus hindfoot caused by neurologic disorders must be individualized. Deformity correction includes release of soft tissue contractures, osteotomies and arthrodeses, and tenotomies or tendon transfers to balance muscle strength and prevent recurrence. To decrease elevated anteromedial ankle joint contact stress and provide lateral hindfoot stability during the entire gait cycle, the goal of static and dynamic hindfoot varus realignment is to fully correct all components of the deformity, but particularly the varus tilt of the talus.

Relationship of the Scarf valgus-inducing osteotomy of the calcaneus to the medial neurovascular structures

BACKGROUND

The Scarf valgus inducing osteotomy of the calcaneus is an operative technique to correct varus deformity of the hindfoot. It is versatile with significant corrective power; however, the neurovascular structures are in close proximity on the medial side and thus may be harmed during the osteotomy. Moreover, because this type of osteotomy can cause a great lateral translation, traction of the medial neurovascular structures is possible. We performed an anatomic study to evaluate the medial soft tissues after a lateralizing Scarf-type calcaneal osteotomy.

MATERIALS AND METHODS

The osteotomies were carried out on ten fresh-frozen cadaver specimens. We performed the osteotomy and induced valgus. Then we performed a medial dissection to identify the important medial structures: the medial and lateral plantar nerve (MPN , LPN) and the posterior tibial artery (PTA). We noted their relation to the osteotomy and their integrity.

RESULTS

In several cases, one or more of the structures were sectioned. In five cases, all the structures crossed the osteotomy, four of which even a transection of one or both of the plantar nerves occurred. Although the PTA crossed the osteotomy in eight specimens, there was no transection of this structure.

CONCLUSION

Scarf osteotomy of the calcaneus is a highly corrective osteotomy. However, caution must be exercised when performing as the medial neurovascular structures cross the osteotomy lines and transection can occur.

CLINICAL RELEVANCE

When performing the osteotomy one should keep in mind that vigorous sawing and large displacement can cause damage to the medial neurovascular structures.

Arteriovenous fistula and pseudoaneurysm of the posterior tibial artery after calcaneal slide osteotomy: a case report

Level of Evidence: V, Expert Opinion