Robert S. Adelaar

Clinical Rating Systems for the Ankle-Hindfoot, Midfoot, Hallux, and Lesser Toes

Four rating systems were developed by the American Orthopaedic Foot and Ankle Society to provide a standard method of reporting clinical status of the ankle and foot. The systems incorporate both subjective and objective factors into numerical scales to describe function, alignment, and pain.

Tibiotalar joint dynamics: indications for the syndesmotic screw: a cadaver study

Pronation-external rotation ankle injuries involve varying degrees of disruption of the syndesmotic ligaments. The loss of ligament support and alteration in the stability of the mortise have been postulated to lead to an increase in joint reactive forces and traumatic arthritis. The purpose of this study was to determine the changes in tibiotalar joint dynamics associated with syndesmotic diastasis as a result of the sequential sectioning of the syndesmotic ligaments to simulate a pronation-external rotation injury. Dissections were conducted on 10 fresh-frozen, knee-disarticulated cadaveric specimens which were then axi-ally loaded in an unconstrained manner. Tibiotalar joint forces were measured at each level of sequential sectioning of the syndesmotic ligaments, the interosseous membrane, and finally the deltoid ligament. Complete disruption of the syndesmosis with the medial structures of the ankle intact resulted in an average syndesmotic widening of 0.24 mm and no significant change in the tibiotalar contact area or the peak pressure. However, deltoid ligament strain increases with sectioning of the syndesmosis. With the addition of deltoid ligament sectioning, there was an average syndesmotic diastasis of 0.73 mm, a 39% reduction in the tibiotalar contact area, and a 42% increase in the peak pressure. In a simulated unconstrained cadaveric model of a pronation-external rotation ankle injury that results in complete disruption of the syndesmosis, if rigid anatomic medial and lateral joint fixation is obtained and the deltoid ligament complex is intact, syndesmotic screw fixation is not required to maintain the integrity of the tibiotalar joint.

The treatment of the cubital tunnel syndrome

Treatment by in situ release, submuscular transposition, and anterior subcutaneous transposition have all been reported to produce satisfactory results for ulnar neuropathy secondary to the cubital tunnel syndrome. A prospective study was done to determine which preoperative clinical and electrical factors and surgical approaches in patients with ulnar nerve palsy at the elbow had the best results. The 32 patients had an average age of 50 years, had symptoms for an average of 15 months before surgery, and underwent postoperative follow-up for an average of 13 months. All patients with good results had no atrophy or preoperative fibrillations in the intrinsic muscles and had an obtainable evoked sensory potential. The change in motor conduction velocity did not correlate with good results. There was no significant difference in the results of the three surgical procedures. Eight of the 37 operations yielded good results, 19 patients showed an improvement, but 10 of the operations yielded poor results. Our results also indicated that surgical results could be predicted by proper patient selection through the assessment of the preoperative physical examination and electromyogram.

Contribution of the Deltoid Ligament to Ankle Joint Contact Characteristics: A Cadaver Study

Changes in ankle biomechanics lead to altered load transmission through the ankle joint, possibly predisposing it to osteoarthritis. Contributions of the different bands of the deltoid ligament to the contact characteristics in the ankle were examined. Fifteen normal cadaveric lower extremities were axially loaded to 445 N after intra-articular Fuji film placement. Ankles were tested in neutral, 10° dorsiflexion, and 10° plantarflexion. Repeated testing was done following sequential sectioning of the deltoid ligament, and the contact characteristics were analyzed. The greatest significant tibiotalar changes (P < 0.0001) occurred after sectioning of the tibiocalcaneal fibers of the superficial deltoid ligament complex. Contact areas decreased up to 43%, peak pressures increased up to 30%, and centroids moved 4 mm laterally, on average. In contrast, sectioning of the other bands led to insignificant changes in joint contact characteristics. The data indicate that significant changes in contact characteristics occur before radiographic evidence of deltoid ligament damage is evident, and may indicate that greater attention to the medial side of the ankle is indicated to restore normal biomechanics to this joint.

Effect of Isolated Talocalcaneal Fusion on Contact in the Ankle and Talonavicular Joints

A cadaveric model was developed to establish the articular contact area and load distribution in the ankle joint, posterior facet of the talocalcaneal joint, and talonavicular joint using pressure sensitive film. Positions of dorsiflexion, neutral, and plantarflexion were evaluated. This model was further used to determine the effect of talocalcaneal fusion on the articular contact area in the talonavicular and ankle joints. Alteration of articular contact was most pronounced in the talonavicular joint. There, a statistically significant reduction in contact area postfusion was noted when the foot was in the plantarflexed position. Reductions in ankle joint articular contact area were observed in the dorsiflexed and plantarflexed positions in the majority of specimens. Lateral displacement of the region of articular contact was noted in some specimens. A pressure-weighted centroid calculation was performed to provide a quantitative measure of the shift of the contact region.

Effects of Medializing Calcaneal Osteotomy on Achilles Tendon Lengthening and Plantar Foot Pressures

Posterior tibial tendon insufficiency, or adult acquired flatfoot deformity, involves collapse of the longitudinal arch of the foot with ensuing changes in the bony architecture of the foot as well. While it is generally accepted that a medializing calcaneal osteotomy (MCO) is a very useful treatment for restoring the fallen arch, questions regarding the effects of this procedure upon plantar foot pressures and Achilles tendon length changes need to be answered. This study focuses on changes in plantar foot pressures and Achilles tendon length as the result of performing a MCO. Fourteen fresh-frozen cadaver legs were used to test the effects of MCO on Achilles tendon length changes 2 cm proximal to the Achilles tendon insertion on the calcaneus. Differential variable reluctance transducers were anchored in ventromedial, dorsomedial, dorsolateral, and ventrolateral positions of the Achilles tendon at the aforementioned level. The effects of the MCO on plantar foot pressures were assessed simultaneously using the Tekscan HR Mat. Axial loading (100 lbs) of each specimen was performed in neutral and dorsiflexion (15°). Data were gathered for Achilles tendon length changes and plantar foot pressures for three trials in both the neutral and dorsiflexed positions. A medializing calcaneal osteotomy (1 cm medial translation) was then performed and testing was repeated in the fashion outlined heretofore. Analysis of the data revealed that there was no significant increase in Achilles tendon length as a result of the MCO. The data also showed that average pressure over the first and second metatarsal regions of the forefoot decreased significantly after MCO. At the same time there was a significant increase in average pressure over the medial and lateral aspect of the heel. These findings suggest that the Achilles tendon aids in inversion of the forefoot without undergoing a significant increase in length change of Achilles tendon fibers in any of the regions tested.

Biomechanical comparison of ankle arthrodesis techniques: crossed screws vs. blade plate.

Many different techniques for ankle arthrodesis have been described. Experience at our institution with crossed screws internal fixation has not met the 90+% union rate reported in the literature. A compression blade plate is one technique for ankle arthrodesis which has not been evaluated biomechanically. A biomechanical study comparing two groups of sawbone ankle fusion constructs fixed with crossed screws and compression blade plates was performed in order to evaluate the stiffness and rigidity of these two arthrodesis techniques. The crossed screws construct demonstrated superior stiffness during dorsiflexion (p < 0.001) and valgus (p < 0.001) loading. The two constructs were found to have equal strength in resisting plantarflexion, varus and torsional loads although there was a trend for greater resistance by the crossed screws construct. These findings lend biomechanical support to the use of crossed screws for tibiotalar arthrodesis.

The practical biomechanics of running

The foot and ankle is a complex structure made of many small bones with capsular and ligamentous con straints. The physiology, kinematics, and muscle inter action of the walking, jogging, and running cycles will be discussed and the current biomechanical literature reviewed. To analyze the pathologic state, one must be aware of the normal stresses and functions of the running cycle. This knowledge establishes a rational basis for the interpretation of problems in providing medical and orthotic treatment.

Plantar pressure analysis in cadaver feet after bony procedures commonly used in the treatment of stage II posterior tibial tendon insufficiency.

Background: Bony procedures play an essential role in the operative treatment of stage II posterior tibial tendon insufficiency and often substantially alter the loading characteristics of the foot. Methods: Eight matched pairs of cadaver lower extremities were axially loaded onto a TekScan HR Mat. (TekScan, Inc., South Boston, MA) After intact testing, each specimen had a lateral column lengthening (either a calcaneocuboid distraction arthrodesis [CCDA] or Evans procedure), a medializing calcaneal osteotomy (MCO), and a plantarflexion (Cotton) osteotomy of the medial cuneiform. The measured plantar pressures were divided into three forefoot regions, two midfoot regions, and two hindfoot regions. For each region, average pressure, peak pressure, and contact area data were collected. Results: Despite the fact that both lateral column lengthening procedures resulted in increased lateral forefoot pressures, no significant differences were noted between the CCDA and the Evans procedure. The addition of a MCO did not significantly alter the plantar pressures measured after the lateral column lengthening alone. Although the Cotton osteotomy resulted in increased average pressures within the medial forefoot, a compensatory significant decrease in lateral forefoot pressures was not observed. Conclusions: The present study demonstrated increased lateral forefoot pressures after a combined lateral column lengthening and MCO and does not support the idea that a Cotton osteotomy significantly reduces loading of the lateral forefoot. Clinical Relevance: The incidence of lateral forefoot pain and fifth metatarsal stress fractures subsequent to either lateral column lengthening procedure may not significantly decline after a Cotton osteotomy.

Plantar pressure and Load in cadaver feet After a Weil or chevron osteotomy

Background: Since metatarsal osteotomy was first used to treat metatarsalgia in the early twentieth century, many techniques have been described to accomplish the basic aim of reduction of load transmission through the operated metatarsal and reduction of localized high pressure on the plantar surface of the metatarsal. Our study examined two popular distal metatarsal neck osteotomies used for the relief of central metatarsalgia and the biomechanical changes that result from their use in a cadaver forefoot model. Methods: After applying 445N (100 lbs) of axially directed force, we measured plantar pressure using the TekScan HR Mat™ (TekScan, Inc., South Boston, MA) in twelve paired, thawed, fresh-frozen intact cadaver legs, then after either a Weil or chevron osteotomy of the second metatarsal and finally after the addition of the same osteotomy of the third metatarsal. Results: Load in the forefoot was not significantly affected by the Weil osteotomy. A significant increase in load was produced in the first metatarsal region, and significant decreases in load were produced beneath the operated metatarsal heads after the chevron osteotomy. Average pressure in the contact area of the forefoot showed similar trends; however, load and pressure changes occurred independently, owing to the changes in contact area produced by the osteotomies. No significant changes were observed in the nonoperated metatarsal regions. Conclusions: In this model, the chevron osteotomy more effectively reduced load and plantar pressure in the operated metatarsal regions; however, increases in load and pressure were observed in the first metatarsal region. The increase in pressure without a change in load in region 3 (third metatarsal) after a Weil osteotomy of the third metatarsal was attributed to the creation of a plantar prominence. This study did not show a reduction in load transmission as a result of the Weil osteotomy, which contradicts the proposed mechanism of clinical benefit. An intact first ray likely prevents transfer of load or pressure to adjacent lesser metatarsals with chevron osteotomy.