Flexor digitorum longus transfer and medial displacement calcaneal osteotomy for the treatment of stage II posterior tibial tendon dysfunction: kinematic and functional results of fifty one feet

Impact of the medial displacement calcaneal osteotomy on foot biomechanics: a systematic literature review

INTRODUCTION

Progressive collapsing foot deformity (PCFD), formally known as "adult-acquired flatfoot deformity" (AAFFD), is a complex foot deformity consisting of multiple components. If surgery is required, joint-preserving procedures, such as a medial displacement calcaneal osteotomy (MDCO), are frequently performed. The aim of this systematic review is to provide a summary of the evidence on the impact of MDCO on foot biomechanics.

MATERIALS AND METHODS

A systematic literature search across two major sources (PubMed and Scopus) without time limitation was performed according to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) criteria. Only original research studies reporting on biomechanical changes following a MDCO were included. Exclusion criteria consisted of review articles, case studies, and studies not written in English. 27 studies were included and the methodologic quality graded according to the QUACS scale and the modified Coleman score.

RESULTS

The 27 included studies consisted of 18 cadaveric, 7 studies based on biomechanical models, and 2 clinical studies. The impact of MDCO on the following five major parameters were assessed: plantar fascia (n = 6), medial longitudinal arch (n = 9), hind- and midfoot joint pressures (n = 10), Achilles tendon (n = 5), and gait pattern parameters (n = 3). The quality of the studies was moderate to good with a pooled mean QUACS score of 65% (range 46-92%) for in-vitro and a pooled mean Coleman score of 58 (range 56-65) points for clinical studies.

CONCLUSION

A thorough knowledge of how MDCO impacts foot function is key in properly understanding the postoperative effects of this commonly performed procedure. According to the evidence, MDCO impacts the function of the plantar fascia and Achilles tendon, the integrity of the medial longitudinal arch, hind- and midfoot joint pressures, and consequently specific gait pattern parameters.

Identifying changes in dynamic plantar pressure associated with radiological knee osteoarthritis based on machine learning and wearable devices

BACKGROUND

Knee osteoarthritis (KOA) is an irreversible degenerative disease that characterized by pain and abnormal gait. Radiography is typically used to detect KOA but has limitations. This study aimed to identify changes in plantar pressure that are associated with radiological knee osteoarthritis (ROA) and to validate them using machine learning algorithms.

METHODS

This study included 92 participants with variable degrees of KOA. A modified Kellgren-Lawrence scale was used to classify participants into non-ROA and ROA groups. The total feature set included 210 dynamic plantar pressure features captured by a wearable in-shoe system as well as age, gender, height, weight, and body mass index. Filter and wrapper methods identified the optimal features, which were used to train five types of machine learning classification models for further validation: k-nearest neighbors (KNN), support vector machine (SVM), random forest (RF), AdaBoost, and eXtreme gradient boosting (XGBoost).

RESULTS

Age, the standard deviation (SD) of the peak plantar pressure under the left lateral heel (f_L8PPP_std), the SD of the right second peak pressure (f_Rpeak2_std), and the SD of the variation in the anteroposterior displacement of center of pressure (COP) in the right foot (f_RYcopstd_std) were most associated with ROA. The RF model with an accuracy of 82.61% and F1 score of 0.8000 had the best generalization ability.

CONCLUSION

Changes in dynamic plantar pressure are promising mechanical biomarkers that distinguish between non-ROA and ROA. Combining a wearable in-shoe system with machine learning enables dynamic monitoring of KOA, which could help guide treatment plans.

Minimally invasive surgery in medial displacement calcaneal osteotomy for acquired flatfoot deformity: a systematic review of the literature

BACKGROUND

Minimally invasive surgery (MIS) in medial displacement calcaneus osteotomy (MDCO) has been proposed for surgical correction of adult-acquired flat foot deformity (AAFD) to reduce complications of open approaches. The aim of our study is to systematically analyze complications and the clinical and radiological results of MIS- MDCO.

METHODS

A systematic review of the English literature was performed on 30th October 2023. Randomized controlled trials and non-randomized trials, cohort studies, case-control studies and case series concerning surgical correction of AAFD with MIS-MDCO and with at least 15 patients were included. Case reports, technical notes, animal or cadaveric studies were excluded. The quality and risk of bias of the studies included were evaluated using GRADE and MINORS systems. Complications rate, clinical and radiological results were inferred from the studies included.

RESULTS

Nine articles were included. A total of 501 cases treated with MIS-MDCO were analysed with a mean follow-up of 11.9 ± 5.1 months. The reported wound infection rate was about 3% and sural neuropathy was rated about 1%. Only 4% of the cases required removal of the screw for pain. In the comparative studies (MIS versus Open MDCO), comparable clinical results but with significant differences (P < 0.001) in infection rates (1% versus 14%) and sural neuropathy (2% versus 1%) were observed.

CONCLUSION

AAFD correction performed with MIS-MDCO, with the limitation of a poor quality and high risk of bias of the included studies, seems to provide good clinical results and high subjective satisfaction with a lower complication rate compared to open approach. Further high-quality long-term comparative studies could better clarify complications and clinical and radiological outcomes of the MIS technique in the treatment of AAFD.

LEVEL OF EVIDENCE

Level IV.

Endoscopic assisted flexor digitorum longus transfer in flexible flatfoot

BACKGROUND

Posterior tibial tendon insufficiency is the commonest cause of adult flexible flatfoot. Transfer of the flexor digitorum longus (FDL) has been described a therapeutic arsenal in flexible flat feet and posterior tibial tendon disorders. It is often combined with bony procedure (open or percutaneous calcaneal osteotomy).

METHODS

We describe a technique and the steps endoscopic approach of FDL transfer.

RESULTS

The procedure is able to be performed safely and reproducible under perfect viewing CONCLUSION: In the future with a clinical study investigating, we purpose the results of such surgery in a cohort of patients with flexible flatfoot. Level IV Therapeutic study: case serie. No funding was received for this research project.

Biomechanical Effects of Surgical Reconstruction for Flexible Progressive Collapsing Foot Deformity: A Systematic Review

BACKGROUND

Symptomatic progressive collapsing foot deformity (PCFD) is frequently treated with reconstructive surgery. Multiple studies have documented successful treatment based on improvements in symptoms and physical examination findings. However, it is not well-established whether there are corresponding improvements in gait function following surgical treatment for PCFD.

METHODS

A systematic review of biomechanical outcomes of treatments for flexible PCFD was conducted on PubMed. The 4 articles chosen involved patients with symptomatic flexible PCFD who underwent a reconstructive surgery. Surgical interventions included osteotomy, tendon transfer, and/or ligament repair or reconstruction. Primary outcomes involved objective quantifiable measurements of kinematic, kinetic, or temporospatial parameters.

RESULTS

The initial search yielded 605 articles, from which 26 were retained after screening the title and abstract. Twenty-two were eliminated yielding 4 articles. Temporospatial, kinematic, and kinetic parameters were all altered after the patients underwent surgical intervention. Specifically, stride length, cadence, and walking speed all improved postoperatively. Walking kinetics also improved with restoration of normal motion in the frontal and sagittal planes and improvements in the dorsiflexion angle. There were also improvements in sagittal power.

DISCUSSION

Surgical intervention to treat flexible PCFD improves objective biomechanical outcomes; however, more follow-up studies are needed to establish the reliability and durability of these improvements.

LEVEL OF EVIDENCE

Level III: Systematic review.

Biomechanical comparisons of different diagonal screw designs in a novel embedded calcaneal slide plate

BACKGROUND

Medial displacement calcaneal osteotomy (MDCO) is frequently used for the surgical correction of flatfoot. This study aims to investigate the biomechanical effect of the different diagonal screw design on a novel-designed embedded calcaneal plate for MDCO using finite element analysis (FEA), mechanical test and digital image correlation (DIC) measurement.

METHODS

Four groups according to the varied implanted plate were set as control group (Group 1), non-diagonal screw (Group 2), one-diagonal screw (Group 3), and two-diagonal screws groups (Group 4). For FEA, A 450 N load was applied to on the anterior process of the calcaneus from top to bottom. Observational indices included the stress on the cortical and cancellous bone of the calcaneus surrounding the implant, the plate itself as well as screws, and the displacement of the overall structure. In addition, this study also used in vitro biomechanics test to investigate the stiffness of the structure after implantation, and used DIC to observe the displacement of the calcaneus structure after external force.

RESULTS

Under a simulated load in FEA, there are significant overall instability and high stress concentration on the calcaneal surrounding host bone and the plate/screws system, respectively, in group 2 compared with other groups. Regard to the mechanical testing with DIC system, significant increased rotation stability, maximum force and stiffness with the addition of diagonal screws. In comparison to Group 2, the increase of 112% and 157% in maximum force as well as 104% and 176% in stiffness were found in Group 3 and 4, respectively.

CONCLUSION

For reducing stress concentration and enhancing overall stability, more than one-diagonal screw design is recommended and two-diagonal screws design will be superior. This study provided biomechanical references for further calcaneal implants design to prevent clinical failure after MDCO.

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.

Natural History of 321 Flatfoot Reconstructions in Adult Acquired Flatfoot Deformity Over a 14-Year Period

The purpose of this study was to report the natural history, demographics, and mechanisms of requirement for additional surgery in patients undergoing flatfoot reconstruction for adult acquired flatfoot. A total of 321 consecutive patients undergoing flatfoot reconstruction over a 14-year period were included (2002-2016). All procedures were performed by a senior orthopaedic foot and ankle surgeon at our institution. Demographic data, operative reports, clinic notes, and radiographs were available for review. Statistical analysis included calculation of relative risk (RR) ratios. The majority of patients were female (83.2%,) and most patients were overweight with a body mass index greater than 25 kg/m² (56.4%). Patient comorbidities included diabetes (13.7%) and rheumatoid arthritis (3.7%). Additional surgery was required for 54 patients (16.8%). The most common reasons for additional surgery were the following: painful calcaneal hardware (57.4%), conversion to triple arthrodesis (16.7%), and wound healing complications (9.1%). An increased risk of need for additional surgery was associated with female gender (RR = 3.4; P = .0005), smoking status (RR = 1.9; P = .0081), and age (<60 years of age; RR = 1.8; P = .042). Although retrospective, the results provide insight into the natural history of this procedure. Clinicians may use these data to appropriately counsel patients who are at increased risk of requirement for additional surgery, such as smokers, women, and patients <60 years old, regarding treatment options.Levels of Evidence: Level IV.

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.

Tendoscopy of Achilles, peroneal and tibialis posterior tendons: An evidence-based update

BACKGROUND

Tendoscopy has been proposed in treating several conditions affecting tendons around the ankle. We reviewed literature to investigate the efficacy of Achilles, peroneal and tibialis posterior tendoscopy.

METHODS

Following the PRISMA checklist, the Medline, Scopus and EMBASE databases were searched, including studies reporting patients affected by disorders of Achilles, peroneal and tibialis posterior tendons and treated by tendoscopy (or tendoscopic-assisted procedures). The tendoscopic technique, rehabilitation protocol, clinical scores, patient satisfaction, success and failure rates and complications were evaluated.

RESULTS

Sixteen studies (319 procedures) dealt with Achilles tendoscopy, nine (108) and six (78) about peroneal and tibialis posterior, respectively. Wound healing, cosmetic results, complication rate, work and sport resumption delay were satisfactory. Clinical scores, classification methods and rehabilitation protocols adopted were heterogeneous.

CONCLUSIONS

The recent scientific evidence suggests that tendoscopy and endoscopic-assisted percutaneous procedures are a safe and effective treatment in chronic and acute disorders of tendons around the ankle.

Role of Tendoscopy in Treating Stage II Posterior Tibial Tendon Dysfunction

BACKGROUND

Stage II tibialis posterior tendon dysfunction (PTTD) resistant to conservative therapies is usually treated with invasive surgery. Posterior tibial tendoscopy is a novel technique being used in the assessment and treatment of posterior tibial pathology. The aims of this study were (1) to clarify the role of posterior tibial tendon tendoscopy in treating stage II PTTD, (2) to arthroscopically classify spring ligament lesions, and (3) to compare the arthroscopic assessment of spring ligament lesions with magnetic resonance imaging (MRI) and ultrasonographic (US) data.

METHODS

We reviewed prospectively collected data on 16 patients affected by stage II PTTD and treated by tendoscopy. We report the reoperation rate and functional outcomes evaluated by comparing pre- and postoperative visual analogic scale for pain (VAS-pain) and the Short-Form Health Survey (SF-36; with its physical [PCS] and mental [MCS] components). Postoperative satisfaction was assessed using a VAS-satisfaction scale. One patient was lost to follow-up. Spring ligament lesions were arthroscopically classified in 3 stages. Discrepancies between preoperative imaging and intraoperative findings were evaluated.

RESULTS

At a mean of 25.6 months' follow-up, VAS-pain ( P < .001), SF-36 PCS ( P = .039), and SF-36 MCS ( P < .001) significantly improved. The mean VAS-satisfaction score was 75.3/100. Patients were relieved from symptoms in 80% of cases, while 3 patients required further surgery. MRI and US were in agreement with intraoperative data in 92% and 67%, respectively, for the tendon assessment and in 78% and 42%, respectively, for the spring ligament.

CONCLUSIONS

Tendoscopy may be considered a valid therapeutic tool in the treatment of stage II PTTD resistant to conservative treatment. It provided objective and subjective encouraging results that could allow continued conservative therapy while avoiding more invasive surgery in most cases. MRI and US were proven more useful in detecting PT lesions than spring ligament tears. Further studies on PT could use this tendoscopic classification to standardize its description.

LEVEL OF EVIDENCE

Level IV, therapeutic study, case series.

Return to sport activities after medial displacement calcaneal osteotomy and flexor digitorum longus transfer

PURPOSE

Medial displacement calcaneal osteotomy with flexor digitorum longus transfer is a common treatment for the management of the adult flatfoot associated with posterior tibial tendon dysfunction. In the literature, there is a paucity of information regarding the ability of patients to return to sport and recreational activities after this surgical procedure. The purpose of this retrospective clinical study was to assess the rate and type of athletic activities that patients participated in before and after medial displacement calcaneal osteotomy with flexor digitorum longus transfer.

METHODS

A consecutive series of 42 patients with a mean age at surgery of 41 years (range 19-74 years) was evaluated with a minimum follow-up of 24 months (range 18-31 months). Pre- and post-operative sporting activities were assessed. At final follow-up, patients were asked to complete a Sports Athlete Foot and Ankle Score (SAFAS). Each patient was also evaluated with weight-bearing radiographs of the foot before surgery and at final follow-up.

RESULTS

Preoperatively, 27 of 42 (64.3 %) patients were engaged in athletic activities, participating in an average of 1.4 h/week (range 0-6 h/week); post-operatively, 36/42 (85.7 %) participated in sport and recreational activities for an average of 3.5 h/week (range 0-15 h/week). Meary's angle improved significantly from 11.5 ± 6.2 degrees preoperatively to 7.0 ± 5.7 degrees at final follow-up (p < 0.01); calcaneal pitch improved significantly from 16.5 ± 4.6 degrees to 19.0 ± 5.0 degrees (p < 0.01). At final follow-up, patients demonstrated good SAFASs in symptom tolerance (86.4 %), pain tolerance (89.0 %), daily living performance (96.1 %), and sports performance (86.7 %).

CONCLUSION

The majority of patients returned to sports and recreational activity after medial displacement calcaneal osteotomy and flexor digitorum longus for the treatment of adult flatfoot associated with posterior tibial tendon dysfunction.

LEVEL OF EVIDENCE

III.

Anatomical Study of the Neurovascular in Flexor Hallucis Longus Tendon Transfers

The transfer of the flexor hallucis longus tendon or flexor digitorum longus tendon is frequently used for the treatment of posterior tibial tendon insufficiency or chronic Achilles tendinopathy. According to several anatomical studies, harvesting the flexor hallucis longus (FHL) tendon may cause nerve injury. Sixty-eight embalmed feet were dissected and anatomically classified to define the relationship between Henry’s knot and the plantar nerves. Two different configurations were identified. In Pattern 1, which was observed in 64 specimens (94.1%), the distance between the medial plantar nerve and Henry’s knot was 5.96 mm (range, 3.34 to 7.84, SD = 1.12). In Pattern 2, which was observed in 4 specimens (5.9%), there was no distance between the medial plantar nerve (MPN) and Henry’s knot. No statistically significant difference was observed according to gender or side (p > 0.05). A retraction was performed to harvest the FHL through the posteromedial hindfoot incision using a single minimally invasive technique, and the medial and lateral plantar nerve lesions were scrupulously assessed. In conclusion, medial and lateral plantar nerve injuries did not occur more frequently, even after performing a single minimally invasive incision to harvest the FHL tendon, due to the large distance between the FHL tendon and the medial and lateral plantar nerves.

CT and MR Imaging of the Postoperative Ankle and Foot

A variety of surgical procedures exist for repair of both traumatic and degenerative osseous and soft-tissue pathologic conditions involving the foot and ankle. It is necessary for the radiologist to be familiar with these surgical procedures, so as to assess structural integrity, evaluate for complicating features, and avoid diagnostic pitfalls. Adequate interpretation of postoperative changes often requires access to surgical documentation to evaluate not only the surgery itself but the expected timeline for resolution of normal postoperative changes versus progressive disease. Appropriate use of surgical language in radiology reports is another important skill set to hone and is instrumental in providing a high-quality report to the referring surgeons. The pathophysiology of a myriad of surgical complaints, beginning from the Achilles tendon and concluding at the plantar plate, are presented, as are their common appearances at computed tomography and magnetic resonance imaging. Commonly encountered entities include Achilles tendon tear, spastic equinus, nonspastic equinus, talar dome osteochondral defect, tarsal tunnel syndrome, plantar fasciitis, pes planovalgus, pes cavovarus, peroneal tendinosis, lateral ligament complex pathology, Morton neuroma, plantar plate tear, and metatarsophalangeal joint instability. Computer-generated three-dimensional models are included with many of the procedures to provide a more global view of the surgical anatomy. Correlation with intraoperative photographs is made when available. When appropriate, discussion of postoperative complications, including entities such as infection and failure of graft integration, is presented, although a comprehensive review of postoperative complications is beyond the scope of this article. Notably absent from the current review are some common foot and ankle procedures including hallux valgus and hammertoe corrections, as these are more often evaluated radiographically than with cross-sectional imaging. ^©RSNA, 2016.

Calcaneal Osteotomies: Pearls and Pitfalls

Adult acquired flatfoot deformity is a debilitating condition typically affecting middle-aged patients. The multiple components include hindfoot valgus, first ray elevation, medial soft tissue compromise, and forefoot abduction. As the foot becomes unbalanced, the deformity progresses with repetitive loading and time. Untreated patients often need significant reconstructions or extensive arthrodesis after arthritis and joint contractures present. Medializing calcaneal osteotomy is the workhorse operation for correction of hindfoot valgus, reliably correcting deformity with a relatively low complication risk. This article reviews indications, techniques, complications, and outcomes for the medializing calcaneal osteotomy.

Facilitating the interpretation of pedobarography: the relative midfoot index as marker for pathologic gait in ankle osteoarthritic and contralateral feet

Background

Pedobarography offers dynamic information about the foot, but the interpretation of its large data is challenging. In a prior study it was shown that attention can be restricted to pedobarographic midfoot load data. We aim to verify this observation in ankle osteoarthritic and contralateral feet.

Methods

We assessed both feet of 120 patients with end-stage ankle osteoarthritis (OA) and 35 healthy volunteers with AOFAS-score and dynamic pedobarography in barefoot condition. We introduce a new parameter, the Relative Midfoot Index (RMI), representing the depth of the midfoot weighted by the maximal force (MF) in the hindfoot and forefoot. Main outcome measures were the RMI, MF and contact times in the hindfoot, midfoot and forefoot. Ankle OA, contralateral and healthy feet were compared with ANOVA.

Results

The RMI was significantly smaller in OA feet (0.65 ± 0.19) and contralateral feet (0.69 ± 0.15) than in healthy feet (0.84 ± 0.08, p < 0.0001). There was no significant difference between OA and contralateral feet. The RMI showed a correlation of 0.48 with the AOFAS score. Contralateral and OA feet were significantly different from healthy feet (p < 0.001) in all parameters except the hindfoot MF. An RMI <0.8 showed a positive predictive value of 80% and sensitivity of 78% for being unhealthy.

Conclusion

The RMI assists the interpretation of pedobarographic parameters and provides a user-friendly indicator for unhealthy foot conditions with a cut-off value of 0.8. The contralateral feet of ankle OA patients differed significantly from healthy feet and are therefore not suitable as control group.

Level of Evidence: 3 case control study

Minimally invasive calcaneal osteotomy: A cadaveric and clinical evaluation

BACKGROUND

A cadaveric and clinical study was performed to assess whether a minimally invasive technique is a potentially safer alternative compared to a calcaneal osteotomy through an open lateral approach.

METHODS

Cadaveric: A minimally invasive calcaneal osteotomy (MICO) was performed on nine cadaveric specimens. These were examined to identify any nerve injury and to quantify the displacement achieved with the osteotomy. Clinical: A retrospective review of a sequential case series of medializing MICO's performed by the senior author between October 2011 and November 2014 was undertaken.

RESULTS

Cadaveric: Neurological structures remained uninjured in all specimens. The distance of the sural nerve and the main trunk of the tibial nerve to the superior limb of the oblique osteotomy was 6.2±4.8mm (range 0-14mm) and 7.3±3.6mm (range 4-12mm), respectively. The mean coronal shift achieved was 16.7±3.4mm (range 12-21mm). Clinical: The senior author carried out 35 medializing MICO procedures. Radiological and clinical union occurred in all 35 cases (100%). There were no neurovascular or wound complications.

CONCLUSION

Minimally invasive calcaneal osteotomy offers a safe alternative to an open procedure with promising clinical results.

Stabilization of medial longitudinal foot arch by peroneus longus transfer

The mechanical integrity of the medial longitudinal arch depends on the dynamic support of muscles and the static support of ligaments. Although the posterior tibial tendon is the main dynamic stabilizer of the arch, the static structures provide the most support especially while the person is standing. After rupture of the posterior tibial tendon, the spring ligament may be compromised under increased stress and leads to talar derotation and peritalar subluxation. Surgical repair of the spring ligament has become an important adjunct to treating posterior tibial tendon abnormalities. A technique of peroneus longus transfer to augment the static stabilizers of the medial column is described in this article.

Safe Zone for Neural Structures in Medial Displacement Calcaneal Osteotomy: A Cadaveric and Radiographic Investigation

BACKGROUND

We aimed to define reference lines on standard lateral ankle radiographs that could be used intraoperatively to minimize iatrogenic nerve injury risk in medial displacement calcaneal osteotomy.

METHODS

Forty cadaveric specimens were used. In 20 specimens, the sural, medial plantar (MP), and lateral plantar (LP) nerves were sutured to radiopaque wire, and a lateral ankle radiograph was obtained. On the radiograph, a line was drawn from the posterior superior apex of the calcaneal tuberosity to the origin of the plantar fascia and labeled as the "landmark line." A parallel line was drawn 2 mm posterior to the most posterior nerve, and the area between these lines was defined as the safe zone. In 20 additional specimens, an osteotomy was performed 1 cm anterior to the landmark line using a percutaneous or open technique. Dissection was performed to assess for laceration of the sural, MP, LP, medial calcaneal (MC), or lateral calcaneal (LC) nerves.

RESULTS

The safe zone was determined to be within the area 11.2 ± 2.7 mm anterior to the landmark line. After open osteotomy, lacerations were found in 3 of 10 MC nerves and 3 of 10 LC nerves. After percutaneous osteotomy, lacerations were found in 2 of 10 MC nerves and 1 of 10 LC nerves. No lacerations of the sural, MP, or LP nerves were found with either osteotomy.

CONCLUSIONS

The safe zone extended 11.2 ± 2.7 mm anterior to the described landmark line. The MC and LC nerves were always at risk during medial displacement calcaneal osteotomy.

CLINICAL RELEVANCE

Nerve injury to both major and minor sensory nerves is likely underrecognized as a source of morbidity after calcaneal osteotomy. The current study provides a ready intraoperative guideline for minimizing this risk.

Interference screw for fixation of FDL transfer in the treatment of adult acquired flat foot deformity stage II

INTRODUCTION

Flexor digitorum longus transfer and medial displacement calcaneal osteotomy have shown favourable results in the treatment of adult acquired flat foot deformity stage 2. Little is known about the resorbable interference screw for tendon fixation and postoperative patient satisfaction though. Moreover possible changes of radiographic parameters at final follow-up, possible implant-associated complications and differences concerning clinical results at final follow-up to other studies using bone tunnel techniques for fixation of the FDL tendon were investigated.

MATERIALS AND METHODS

21 feet in 21 patients with a mean age of 51 years were evaluated pre- and postoperatively after a standardised operative procedure using MDCO and FDL transfer with interference screw fixation. Patients were evaluated with the American Orthopaedic Foot and Ankle Society Hindfoot Score and the Visual Analogue Scale at an average follow-up of 20 months. Hindfoot radiographic parameters were evaluated according to AOFAS guidelines. For statistical analysis SPSS v.15.0.1 was used.

RESULTS

The average AOFAS Score (from 42 to 95 points) and VAS (from 0.5 to 8 points) both increased significantly (p < 0.001 each) from preoperative to final follow-up as well as the hindfoot valgus (from 10 to 4 degrees (p = 0.005)) and the lateral talo-first metatarsal angle (from 13.6 preoperative to 5.2° at follow-up). 88 percent of patients evaluated the postoperative result with "very good" or "good". Implant-associated complications could not be detected.

CONCLUSION

We conclude that interference screw fixation for FDL transfer is a safe and promising operative technique, allowing a smaller skin incision without disrupting the normal interconnections at the knot of Henry, while achieving very high patient satisfaction and improving postoperative function as well as relieving pain. This method is technically easy to perform, has a low complication risk and we, therefore, recommend this fixation technique in patients with adult acquired flatfoot deformity stage 2.

Anatomical study for flexor hallucis longus tendon transfer in treatment of Achilles tendinopathy

PURPOSE

The purpose of the study was to describe the anatomical variations of the connection between the flexor hallucis longus (FHL) and flexor digitorum longus (FDL) tendons in the knot of Henry in Asians, and quantify the length of FHL tendon graft with different incisions.

METHODS

Sixty-four embalmed feet of 32 cadavers were analyzed anatomically with respect to the individual cross-links in the planta pedis. Single incision technique graft length was measured from the musculotendinous junction of FHL and the point at sustentaculum tali. Double incision technique was measured from musculotendinous junction of FHL and the level of the master knot of Henry. Additionally, minimally invasive incision technique was measured from musculotendinous junction of FHL to the first interphalangeal joint. These three techniques were then combined to determine the total potential tendon graft length obtainable using different approach.

RESULTS

Only two different configurations were found. Type 1, a tendinous slip branched from the FHL to the FDL (62 of 64 feet). Type 2, a slip branched from the FHL to the FDL and another slip from the FDL to FHL (2 of 64). The average length of the FHL graft available from a single incision measured 5.08 cm (range 3.32-10.35, SD = 1.09), double incision technique measured 6.72 cm (range 4.69-12.09, SD = 1.03), and minimally invasive incision measured 17.49 cm (range 13.51-20.52, SD = 1.80). The difference between the lengths obtained from these three techniques was statistically significant (p < 0.001).

CONCLUSION

The absence of no attachment and FDL tendon to the FHL between the two tendons in the foot may be more frequent than previously reported. Only two configurations of the anatomical relationship were found in this study. In over 96 % of the feet, a proximal to distal connection from the FHL to the FDL was found, which might contribute to the residual function of the lesser toes after FDL transfer.