Lateral column calcaneal lengthening, flexor digitorum longus transfer, and opening wedge medial cuneiform osteotomy for flexible flatfoot: a biomechanical study

BACKGROUND: Lengthening of the lateral column is commonly used for reconstruction of the adult and pediatric flatfoot, but can result in supination of the foot and symptomatic lateral column overload. The addition of a medial cuneiform osteotomy has been used to redistribute forces to the medial column. The combined use of a lateral column lengthening and medial cuneiform osteotomy in a reproducible cadaver flatfoot model was evaluated. METHODS: Twelve cadaver specimens were physiologically loaded and each was evaluated radiographically and pedobarographically in the following conditions: 1) intact, 2) severe flatfoot, 3) lateral column lengthening with simulated flexor digitorum longus transfer, and 4) lateral column lengthening and flexor digitorum longus (FDL) transfer with added medial cuneiform osteotomy. The lateral column lengthening was performed with a 10-mm foam bone wedge through the anterior process of the calcaneus, and the medial cuneiform osteotomy was performed with a dorsally placed 6-mm wedge. RESULTS: Lateral column lengthening with simulated FDL transfer on a severe flatfoot model resulted in a significant change as compared with the flatfoot deformity in three measurements: in lateral talus-first metatarsal angle (-17 to -7 degrees; p<0.001), talonavicular angle (46 to 24 degrees; p<0.001), and medial cuneiform height (16 to 20 mm; p<0.001). Lateral forefoot pressure increased from 24.6 to 33.9 kPa (p<0.001) after these corrections as compared with the flatfoot. Adding a medial cuneiform osteotomy decreased the lateral talar-first metatarsal angle from -7 to -4 degrees, decreased the talonavicular coverage angle from 24 to 20 degrees, and increased the medial cuneiform height from 20 to 25 mm. After added medial cuneiform osteotomy, lateral pressure was significantly different from that of the flatfoot (p=0.01) and was not significantly different from that of the intact foot (p=0.14). Medial forefoot pressure was overcorrected as compared with the intact foot with added medial cuneiform osteotomy. CONCLUSIONS: Lateral column lengthening increased lateral forefoot pressures in a severe flatfoot model. An added medial cuneiform osteotomy provided increased deformity correction and decreased pressure under the lateral forefoot.     

Micro-CT Density Analysis of the Medial Wall of the Human Medial Cuneiform

The human medial cuneiform is incompletely characterized with regard to anatomical morphology, including mineral density and bone quality. Clinically, we have observed failures of fixation by pull-through of devices through relatively soft medial bone. Defining patterns of relative density may provide valuable information regarding implant placement as higher cortical density bone may offer better resistance to such failures. We sought to identify an area of greatest density along the medial wall of the medial cuneiform.Ten fresh-frozen human cadaveric medial cuneiforms underwent micro-computed tomography imaging. Images were analyzed to obtain densities in 4 quadrants along the medial wall of the medial cuneiform. Seven of 10 specimens revealed a maximum density in the plantar distal quadrant of the medial wall of the medial cuneiform. Chi-square goodness-of-fit testing indicated that the density of this quadrant was significantly different from 3 other quadrants (P<.009). Using the Principle of Standard Residuals, the density of the plantar distal quadrant was significantly different than the other 3.We conclude that the plantar distal quadrant of the medial cuneiform contains bone of maximal density when compared to 3 other quadrants. Surgeons who place implants in this region should be aware that this area might offer better resistance to fixation failure.     

Accuracy of Palpation to Identify the Medial Branch of the Medial Dorsal Cutaneous Nerve in Medial Column Surgery: Correlation of Preoperative Nerve Marking With Intraoperative Findings During Lapidus Fusion

The medial branch of the medial dorsal cutaneous nerve is frequently encountered in medial column surgery. Postoperative sensory nerve symptoms can lead to dissatisfaction and suboptimal outcome. The purpose of this case series is to correlate intraoperative nerve location on direct viewing with preoperative nerve localization to assess the accuracy of a specific nerve palpation technique. Hundred consecutive patients undergoing elective Lapidus fusion were prospectively evaluated. Preoperative nerve localization and intraoperative comparison was performed along with assessment of nerve position in relation to the cuneiform and first tarsometatarsal joint. Preoperative nerve identification correlated with intraoperative findings in 99 of 100 consecutive cases. In 1 of 100 cases, the palpated nerve was proximal to the zone of dissection and was not visualized. The medial branch of the medial dorsal cutaneous nerve crossed the dorsal Lapidus incision at the medial cuneiform or first metatarsal base level in 95 of 100 cases; at the mid metatarsal level in 2 of 100 cases; and proximal to the medial cuneiform in 3 of 100 cases.     

Anatomic Description of the Distal and Intercuneiform Articulations: A Cadaveric Study

The medial, intermediate, and lateral cuneiforms play a pivotal role in foot biomechanics. When correcting deformities of this joint complex understanding the clinical anatomy remains imperative to provide both anatomic reduction and appropriately sized fixation. This study qualitatively and quantitatively describes the distal and intercuneiform articulations and their clinical implications. The cuneiform complex of 10 fresh-frozen cadavers was dissected, and the width of the complex was measured with digital calipers. Following further dissection, the distal articular surface shapes of each cuneiform were described, and the individual heights and widths were measured. The intercuneiform articular facets were described and the protrusion distances, between the medial and lateral cuneiforms with the intermediate cuneiform, were measured. The width of the joint complex was 44.74 ± 3.40 mm. The medial cuneiform height, width, dorsal anterior, and plantar protrusion distances were 32.58 ± 2.77 mm, 14.08 ± 2.26 mm, 8.51 ± 2.17 mm, and 6.66 ± 1.21 mm, respectively. The intermediate cuneiform height and width was 23.05 ± 1.92 mm and 9.59 ± 1.85 mm, respectively. The lateral cuneiform height, width, dorsal, and plantar anterior protrusion distances were 23.38 ± 2.67 mm, 10.98 ± 3.01 mm, and 6.76 ± 1.43 mm, and 4.19 ± 1.10 mm respectively. The anterior surface of the medial, intermediate, and lateral cuneiforms was described as reniform, triangular, and triangular, respectively. The majority of intermediate cuneiforms shared an inverted L-shaped articulation with the medial cuneiform, and a B-shaped articulation with the lateral cuneiform. The shapes and sizes of distal and intercuneiform articulations were described with shared anatomical features across cadavers. Understanding the dimensions of the respective surfaces allows for anatomically appropriate fixation size.     

The “L-shaped” intermediate cuneiform

We present the case of a 44-year-old lady with an ‘L-shaped’ intermediate cuneiform. Plain radiography did not identify the anomaly but showed osteoarthritic changes in her tarsometatarsal joint. At the time of sugical fusion, an ‘L-shaped’ intermediate cuneiform was observed, preventing the medial cuneiform articulating with the navicular bone. Fusion of the medial through the intermediate, to the navicular bone was successful at resolving her midfoot pain.     

Symptomatic bipartite medial cuneiform in an adult athlete: a case report

We present the case of a 32-year-old female marathon runner with a symptomatic bipartite medial cuneiform. The bipartite articulation was best visualized on a 30 degress external oblique radiograph of the foot. Surgical exploration revealed a noncartilaginous articulation between the two osseous segments. The smaller medial segment was excised. Postoperatively the patient's symptoms resolved, and at one-year follow-up she remains asymptomatic and has returned to competitive running. This case demonstrates that surgical excision is indicated for a symptomatic bipartite medial cuneiform that fails to respond to nonoperative measures.     

Radiographic comparison of standing medial cuneiform arch height in adults with and without acquired flatfoot deformity

BACKGROUND: Adult acquired flatfoot (AAF) is characterized by decreased arch height, talar depression, medial arch depression and elongation, and forefoot abduction. We have measured standing arch height in AAF patients and in a control group of patients using the standing lateral medial cuneiform arch height radiographic measurement. METHODS: Fifteen (25 feet) patients were selected with the clinical diagnosis of symptomatic AAF with no secondary diagnoses. A control group consisted of 36 (72 feet) patients with no foot deformities or prior foot surgeries. Arch height was measured in millimeters using the standing medial cuneiform height on the lateral radiographic view. RESULTS: The mean standing medial cuneiform arch height in the control group was 18.38 mm. The mean arch height in the AAF group was 11.04 mm (p < 0.001). There were no differences between right and left feet in the control group or symptomatic and contralateral feet in the AAF group. Body mass index (BMI) in the control group was 26.17 and in the AAF 33.74. (p = 0.007). CONCLUSION: These data provide a control value for the arch height using the medial cuneiform as reference. The decrease in arch height is a strong indicator of AAF. A study with larger numbers of patients is necessary.     

Isolated medial cuneiform fractures: report of two cases and review of the literature

Although fractures of the midfoot are common, cuneiform fractures are rarely seen. These fractures are frequently associated with other fractures of the midfoot such as Lisfranc fracture-dislocations. However, isolated cuneiform fractures are extremely rare, with few cases reported in the relevant literature. Herein, the authors report 2 cases of isolated medial cuneiform fractures. One of the patients was treated with headless screw fixation due to displacement in fracture configuration, and the other was treated conservatively. Fractures were united without any complication in both patients. In this report, the authors discuss the mechanism of injury, diagnostic challenges, and treatment options of isolated medial cuneiform fractures.     

Observed Changes in First Metatarsal and Medial Cuneiform Positions after First Metatarsophalangeal Joint Arthrodesis

The first intermetatarsal angle (IMA) is known to decrease after first metatarsophalangeal joint arthrodesis, although the exact mechanism by which this decrease occurs is not known. We measured the first IMA and obliquity of the medial cuneiform on anteroposterior weightbearing preoperative and postoperative radiographs in 86 feet and analyzed the statistical correlation between the IMA and the medial cuneiform angle. A change in the first IMA after first metatarsophalangeal joint fusion showed a strong positive correlation with a change in cuneiform obliquity (p < .0001). This finding was consistent in the direction and magnitude in each of 3 clinical subgroups: normal, p = .087; moderate deformity, p = .011; and severe deformity, p = .10. A comparison of the preoperative IMA and cuneiform obliquity revealed a trend toward a positive relationship but did not reach statistical significance (p = .08). The preoperative association between the IMA and medial cuneiform obliquity was not significant in any clinical subgroup, and the postoperative association between the IMA and cuneiform obliquity was not significant (p = .65). Clinical subgroup analysis showed no significant association between the IMA and the normal (p = .73) and moderately (p = .69) deformed feet, although the postoperative association between the IMA and cuneiform obliquity in the severely deformed group was significantly (p = .034) positive. A linear relationship between the reduction of the first IMA and medial cuneiform obliquity after metatarsophalangeal joint fusion was observed. Our findings suggest that frontal plane rotation influences cuneiform obliquity.     

Dorsomedial Fracture Dislocation of the First Ray and Medial Cuneiform: A Case Report

Isolated dislocation of the medial cuneiform is a rare injury. A favorable outcome relies on an accurate and stable reduction. Evidence of residual instability can be subtle. We present 1 such injury whose true extent was not fully appreciated at presentation, despite multiple plain films. Occult fracture of the medial cuneiform contributed to residual instability of the first ray and persistent and progressive symptoms and ultimately necessitated operative stabilization of the medial arch. We recommend the use of computed tomography as an adjunct to plain radiography for all midfoot dislocations to more accurately define the extent of the injury.     

Influence of tendon transfer site on moment arms of the flexor digitorum longus muscle

BACKGROUND: Adult acquired flatfoot is a common condition that leads to significant morbidity. Along with bony procedures to operatively treat this condition, transfer of the flexor digitorum longus (FDL) tendon to the medial cuneiform or navicular is routinely performed. The goal of this tendon transfer is to increase the capacity of the FDL to invert the hindfoot and control the transverse tarsal joints. However, it is not known whether this biomechanical goal is met or whether one transfer site produces a larger mechanical advantage compared to another site. The purpose of this study was to calculate FDL muscle moment arms at the hindfoot with two clinically relevant transfer locations to quantify the change in mechanical advantage of the FDL after tendon transfer. METHODS: In seven cadaver specimens, muscle moment arms of the FDL with respect to hindfoot motion were measured using the tendon excursion method before and after the FDL was transferred to the plantar aspect of the navicular and medial cuneiform. The position and orientation of the foot and excursion of the FDL tendon were measured with an optoelectronic measurement system. RESULTS: The FDL moment arm did not increase after tendon transfer to either the medial cuneiform or navicular when compared to its native site. There were significant decreases in FDL moment arm when transferred from its native site to the medial cuneiform (56% decrease, p=0.018) and navicular (46% decrease, p=0.026). CONCLUSIONS: In contrast to the clinical proposition that FDL transfer to the navicular or medial cuneiform increases this muscle's mechanical advantage to invert the hindfoot, this cadaver study suggests that, to the contrary, FDL muscle moment arms decrease after tendon transfer.     

Opening wedge osteotomy of the medial cuneiform before age 4 years in the treatment of forefoot adduction

Thirty-seven feet in 25 children (12 girls, 13 boys) treated surgically with medial cuneiform opening wedge osteotomy to correct forefoot adduction were assessed. Thirteen patients had unilateral deformity. Primary diagnoses were congenital clubfoot (33 feet), congenital forefoot adduction (3 feet), and skewfoot (1 foot). All children underwent operation before age 4 years. The age at operation ranged from 21 to 47 months (mean 35). In 18 feet, allografts were used. In 5 feet, autograft was used. In 14 feet, ceramic material was inserted as opening wedge. Follow-up ranged from 3 to 8 years (mean 4). In four feet, the ossification center of the medial cuneiform was invisible. The correction of the deformity was assessed clinically and radiographically. The first ray angle and talo-first metatarsal angle were evaluated on anteroposterior radiographs, the latter was evaluated on lateral radiographs, also. In 26 feet, normal position of the forefoot was achieved. In five feet, overgrowth of the medial cuneiform in comparison with the normal side was observed. Forefoot adduction persisted in six feet. The ossification center was often divided into two parts by bone graft, and subsequent independent growth of both parts was observed. This technique is safe and useful for correction of forefoot adduction in young children. It can be performed even in cartilaginous bone. The osteotomy causes overgrowth of the medial cuneiform and the medial ray.     

First cuneiform closing abductory osteotomy for reduction of metatarsus primus adductus.

The closing subtraction osteotomy of the first cuneiform effectively reduces pronounced obliquity of the first metatarsal cuneiform joint and predictably reduces the intermetatarsal angle in patients with metatarsus primus adductus. This osteotomy is combined with other procedures in surgical realignment of the first ray. Cases best suited for this procedure must be selected carefully. The procedure involves resecting the existing bone block from the opposing surfaces of the first and second metatarsal bases and from the distal one half of the opposing surfaces of the first and second cuneiforms. A triangular-shaped wedge of bone is then resected from the midbody of the first cuneiform while retaining a medial hinge. Closure of the first cuneiform osteotomy should require only minimal pressure. Two threaded Steinman pins transfix the osteotomy site. The vascular cancellous bone of the first cuneiform assures adequate healing of the osteotomy site.     

Rupture of the anterior tibial tendon: three clinical cases, anatomical study, and literature review

BACKGROUND: We report three cases of anterior tibial tendon ruptures and the results of an anatomical study in regard to the tendon's insertion site and a literature review. METHODS: Three patients were referred to our hospital with anterior tibial tendon ruptures. In the anatomical study, 53 feet were dissected, looking in particular for variants of the bony insertion of the tendon. RESULTS: Two patients had surgical treatment (one primary repair and one semimembranosus tendon graft) and one conservative treatment. After a mean followup of 14 weeks all patients had satisfactory outcomes. In the anatomical study, we noted three different insertion sites: in 36 feet the tendon inserted into the medial side of the cuneiform and the base of the first metatarsal bone and in 13 feet only into the medial side of the cuneiform bone. In the remaining four feet the tendon inserted into the cuneiform and the first metatarsal bone, but an additional tendon was noted taking its origin from the anterior tibial tendon near its insertion into the medial cuneiform and attaching to the proximal part of the first metatarsal. CONCLUSIONS: According to literature, surgical repair is the treatment of choice for acute ruptures and for patients with high activity levels. For chronic ruptures and patients with low demands, conservative management may lead to an equally good outcome. Knowledge of the anatomy in this region may be helpful for diagnosis and for the interpretation of intraoperative findings and choosing the most appropriate surgical procedure.     

Isolated medial cuneiform tuberculosis: A case report

Skeletal involvement in extrapulmonary tuberculosis is extremely rare, and foot involvement accounts for less than 10% of osteoarticular tuberculosis. Tuberculosis osteomyelitis of the foot can also mimic a wide range of pathology. As a result, this condition is often misdiagnosed, or the true nature of the lesion is identified late in the diagnostic process. This article reports a case of tuberculosis in the medial cuneiform of a 3-year-old girl. Initially misdiagnosed as osteochondrosis, the patient returned 2 years later with a draining sinus on the medial aspect of the left midfoot. New radiographs showed a cystic lesion in the substance of the medial cuneiform. A diagnosis of tuberculosis was established after biopsy and histopathological examination of operative specimen. Antituberculosis treatment was implemented and continued for 16 months. At that time, clinical signs of infection had ceased.     

Symptomatic Os Infranaviculare

The author observed a new accessory bone of the foot in the distal portion of navicular, which articulated with the medial cuneiform and the intermediate cuneiform, and named it os infranaviculare. A degenerative change was observed between the accessory bone and the navicular; this caused midfoot pain to the patient during weight-bearing. Thus, the patient was treated by excision of the accessory bone. The symptom was relieved at one-year postoperative.     

The Cobb procedure for stage II posterior tibial tendon dysfunction.

Flexor digitorum longus transfer or augmentation is currently the most popular adjunctive procedure for the repair of an attenuated or ruptured tibialis posterior tendon. Although the procedure is efficacious, an important functional muscle is sacrificed. Results show that similar results can be achieved with a tenodesis procedure by way of a split anterior tibial tendon repair. The authors have modified the Cobb procedure, and do not create a hole through the medial cuneiform or navicular. The thick, fibrous periosteal tissue at the medial aspect of the cuneiform is a sufficient tunnel for securing and positioning the tibialis anterior tendon. An additional site of healing and potential complications are avoided. The Cobb procedure is a useful and successful treatment option for PTTD, provides strong autograft augmentation to the posterior tibial tendon without sacrificing function of other tendons, and offers the surgeon and patient predictable outcomes with long-term satisfaction.     

Articular geometry of the medial tarsometatarsal joint in the foot: Comparison of metatarsus primus adductus and metatarsus primus rectus

The three-dimensional surface geometry of the medial tarsometatarsal joint ("first metatarsocuneiform") of the first ray was analyzed to determine if the shape of the joint is distinct in the medially deviated first metatarsal with metatarsus primus adductus (MPA). Clinical evaluation of 29 cadaver feet identified 13 feet with MPA and 16 with metatarsus primus rectus (MPR). Three-dimensional (3D) coordinates x, y, z of the first metatarsal and medial cuneiform joint facets of the feet were digitized on a Coordinate Measuring Machine (accuracy = 0.01 mm) and the data fitted with B-spline surfaces from which 3D curvature maps were generated. Comparison of means of surface-averaged maximum and minimum principal curvatures and root-mean-square curvatures showed significant (p < .0005) differences between the MPA and MPR subsets, male and female subsets, and metatarsal and cuneiform subsets. These results show that the articular shape of the medial tarsometatarsal joint in feet with MPA is significantly less contoured, or is flatter, than the same joint in normal or MPR feet. Results also showed that the female joints are more curved than male joints, and that metatarsal and cuneiform facets closely conform in shape to each other. These preliminary results may be related to questions concerning the anatomical and functional basis for the first metatarsal deviation, for radiographic presentation of the joint and surgical options in correcting related forefoot deformities.