Raymond J. Sullivan

Ligamentous Lisfranc Joint Injuries: A Biomechanical Comparison of Dorsal Plate and Transarticular Screw Fixation

Background: The current treatment of displaced ligamentous injuries of the tarsometatarsal (TMT) joints is open reduction and rigid fixation using transarticular screws. This technique causes further articular surface damage that theoretically may increase the risk of arthritis. Should the screws break, hardware removal is difficult. An alternative method that avoids these potential complications is rigid fixation using dorsal plates. Methods: The displacement between the first metatarsal and medial cuneiform, the second metatarsal and intermediate cuneiform, the first and second metatarsal bases, and the medial cuneiform and second metatarsal base were measured in 10 matched pairs of fresh-frozen cadaver lower extremities in the unloaded and loaded condition. After sectioning the Lisfranc and TMT joint ligaments, measurements were repeated in the loaded condition. The first and second TMT joints of the right feet were fixed with transarticular 3.5-mm cortical screws while those of the left feet with were fixed with dorsal 2.7-mm 1/4 tubular plates. Measurements were then repeated in the unloaded and loaded condition. Results: After ligament sectioning, significantly increased first and second TMT joint subluxation with loading was seen. No significant difference was noted with direct comparison between plates and screws with respect to ability to realign the first and second TMT joints and to maintain TMT joint alignment during loading. The amount of articular surface destruction caused by one 3.5-mm screw was 2.0 ± 0.7% for the medial cuneiform, 2.6 ± 0.5% for the first metatarsal, 3.6 ± 1.2% for the intermediate cuneiform, and 3.6 ± 1.0% for the second metatarsal. Conclusions: The model reliably produced displacement of the first and second TMT joints consistent with a ligamentous Lisfranc injury. Transarticular screws and dorsal plates showed similar ability to reduce the first and second TMT joints after TMT and Lisfranc ligament transection and to resist TMT joint displacement with weightbearing load. Clinical relevance: Dorsal plating may be an alternative to transarticular screws in the treatment of displaced Lisfranc injuries.

The Effect of Triceps Surae Contracture Force on Plantar Foot Pressure Distribution

Background: Triceps surae contractures have been associated with foot and ankle pathology. Achilles tendon contractures have been shown to shift plantar foot pressure from the heel to the forefoot. The purpose of this study was to determine whether isolated gastrocnemius contractures had similar effects and to assess the effects of gastrocnemius or soleus contracture on midfoot plantar pressure. Methods: Ten fresh frozen cadaver below-knee specimens were loaded to 79 pounds (350N) plantar force with the foot unconstrained on a 10-degree dorsiflexed plate. Combinations of static gastrocnemius or soleus forces were applied in 3-lb increments and plantar pressure recordings were obtained for the hindfoot, midfoot, and forefoot regions. Results: The percentage of plantar force borne by the forefoot and midfoot increased with triceps surae force, while that borne by the hindfoot decreased (p ≤ 0.005). Increasing gastrocnemius force had similar results. Increasing triceps surae force from 0 to 21 lbs (93 N) increased average percent forefoot and midfoot force 59% and 38%, respectively, and reduced average percent hindfoot force 18%. Increasing gastrocnemius force from 0 to 18 lbs increased average percent forefoot and midfoot force 50% and 32%, respectively, and reduced average percent hindfoot force 16%. For a given triceps surae force, there was no statistical difference in pressure distribution noted between different combinations of gastrocnemius and soleus force. Conclusions: In a static model, increased triceps surae or isolated gastrocnemius force shifted weightbearing plantar pressure from the hindfoot to the midfoot and forefoot. Similar results were noted whether the triceps surae force was applied through the gastrocnemius or soleus or both. The results of this study are consistent with the clinical association of triceps surae contracture with foot and ankle disorders including diabetic foot ulcers and metatarsalgia. The similar effects with triceps surae force application through the gastrocnemius or soleus suggest that patients with isolated gastrocnemius contractures may obtain similar clinical benefits with potentially less morbidity after gastrocnemius aponeurosis lengthening as compared to Achilles tendon lengthening.

Flexor Hallucis Longus Transfer for Repair of Chronic Achilles Tendinopathy

Background: The flexor hallucis longus (FHL) tendon has been used to augment the repairs for chronic Achilles tendinopathy. Two common methods of FHL harvesting include a single incision (posterior) technique and a double incision (posterior and medial utility) technique. This cadaver study was designed to measure and compare the lengths of FHL tendon obtainable for reconstruction with each technique. Methods: Fourteen fresh-frozen cadaver lower limbs were utilized for FHL harvest. The tendon was first exposed through the single posterior-medial incision approach adjacent to the Achilles. A second medial utility midfoot incision was then made and the FHL was marked at the level of Henrys knot with a suture, to approximate the level of potential harvest via a two-incision technique. The FHL was then harvested and delivered into the posterior wound. Single incision technique graft length was then measured from the tip of the calcaneal tuber to the level of transection. The remaining in situ tendon was then also measured between its level of transection and the more distal suture placed at Henrys knot. These two lengths were then combined to determine the total potential tendon graft length obtainable using a double incision technique. Results: The average length of the FHL tendon harvested through the single posterior incision technique measured 5.16 cm (range, 3.4–6.9 cm, SD = 1.29). The average total tendon graft length available using the double incision technique measured 8.09 cm (range, 5.1–11.1 cm, SD = 1.63). The difference between the lengths obtained from these two techniques was significant (p < .001). Conclusions: These results demonstrate approximate FHL graft lengths obtainable by using either a single or double incision harvest technique and show that a significantly longer graft can be obtained using a double incision technique. Further data need to be obtained, however, to support whether the extra surgery and graft length obtained from a double incision technique are of any benefit in improving the ultimate functional outcome of these repairs.

Cyclic loading of achilles tendon repairs : A comparison of polyester and polyblend suture

Background: Early functional rehabilitation is widely used after open suture repair of the Achilles tendon. To our knowledge, no previous studies have assessed gap formation from cyclic loading and subsequent failure loads of simulated Achilles tendon repairs. A synthetic (polyblend) suture has been introduced for tendon repairs with reportedly greater strength than polyester suture. This stronger, stiffer suture material may provide stronger repairs with less elongation of the tendon repair. Methods: Simulated Achilles tendon ruptures in bovine Achilles tendon were repaired with a four-strand Krackow suture technique using No. 2 polyester suture. Specimens were loaded for 3000 cycles at maximal loads of 50, 75,100, or 125 N, and gap formation at the repair site was continuously measured. After cyclic loading, each specimen was loaded to failure. Identical repairs were performed with number 2 polyblend suture and cyclically loaded to 75 N for 3000 cycles. All specimens were loaded to failure. Results: Cyclically loading polyester suture repairs to 50, 75, 100, or 125 N for 3000 cycles resulted in mean gapping at the repair site of 3.0 ± 0.8,4.9 ± 1.0,7.2 ± 0.9, and 7.9 ± 0.8 mm, respectively. Cyclically loading the polyblend suture repairs for 3000 cycles at 75 N, resulted in 3.3 ± 0.3 mm of gap formation at the repair site, significantly less than polyester suture repairs (p < 0.001). The mean load to failure for polyester suture repair was 222 ± 19 N and for polyblend suture repair was 582 ± 49 N, a statistically significant difference (p < 0.001). Gap formation at 100, 1000, and 2000 cycles, as a percentage of total gap formation at 3000 cycles, was 64.3%, 87.5%, and 95.4% for polyester suture and 45.8%, 78.5%, and 90.1% for polyblend repairs. All specimens in all groups failed at the knots during load-to-failure testing. Conclusions: Cyclic loading of simulated Achilles tendon repairs using a Krackow, four-core polyester suture technique showed progressive gap formation with increasing load. All repairs failed at the knot, and suture pull-out from tendon was not observed. Polyblend suture repair, when compared to identical repairs with braided polyester suture, resulted in a 260% higher load to failure and 33% less gap formation at the repair site after 3000 cycles. Clinical Relevance: The use of polyblend suture in a four-stranded Krackow configuration provides stronger repairs with less gap formation, which may provide increased security during early functional rehabilitation.

Arthroscopic treatment of soft-tissue impingement lesions of the ankle in adolescents.

Background: Ankle sprains are common injuries in adolescents. Most are treated conservatively with rest, ice, antiinflammatory medication, and rehabilitation. A small percentage of patients develop chronic pain and functional instability secondary to intraarticular soft-tissue impingement. This study evaluated the effectiveness of ankle arthroscopy for the treatment of functional instability of the ankle with pain specifically in adolescents between the ages of 13 and 19 years. Methods: We evaluated 11 patients at an average of 25 (range 15 to 38) months after arthroscopic debridement. The American Orthopaedic Foot and Ankle Society (AOFAS) ankle and hindfoot score was used to evaluate outcomes. In addition, four questions were asked: 1) Are you satisfied with the outcome of your surgery? 2) Would you have the procedure again? 3) Would you recommend it to a friend? 4) Have you returned to your preinjury level of activity. Results: The average postoperative AOFAS score was 95 (range 75 to 100). We found that 10 of 11 patients had good to excellent results with arthroscopic debridement of soft-tissue, intraarticular impingement lesions. All but one patient was satisfied with the procedure and all stated that they would have the procedure again. Two patients had repeat injuries and one subsequently developed reflex sympathetic dystrophy. These two patients had not yet returned to their preinjury level of activity at last followup. Conclusions: We found ankle arthroscopy to be a safe and effective means of treatment in adolescents with functional instability from soft-tissue ankle impingement.

An in vitro study comparing the use of suture anchors and drill hole fixation for flexor digitorum longus transfer to the navicular

Background: The surgical management of posterior tibial tendon dysfunction often includes transfer of the flexor digitorum longus (FDL) tendon through a tunnel in the navicular. Fixation often is obtained by sewing the tendon back onto itself. The purpose of this study was to compare this standard method of fixation with suture anchor fixation, a technique that may be associated with less surgical morbidity, because it requires the harvesting of less tendon length. Methods: FDL tendon transfer to the navicular was done in 13 fresh-frozen cadaver specimens. In six feet comprising the standard group, the FDL tendon was transected distal to the master knot of Henry, placed through a drill hole into the navicular, and sutured back onto itself. In seven feet the FDL tendon was transected proximal to the master knot of Henry, placed into a drill hole into the navicular, and fixed with a suture anchor. Load was applied to the proximal FDL muscle and tendon using a materials testing system (MTS) machine and peak load to failure was measured. Results: The mean load to failure was 142.48 N ± 38.06 N for the standard group and 142.12 N ± 59.26 N for the suture anchor group (p = 0.305 for the Student-t test and p = 0.945 for the Mann-Whitney test). Conclusion: Transfer of the FDL tendon to the navicular using suture anchor fixation requires less tendon length yet provides similar fixation strength as compared to sewing the tendon back onto itself. However, suture anchors are considerably more expensive than sutures. Clinical Implications: Suture anchors allow comparable fixation of FDL tendon transfer into a navicular without the need to disrupt the master knot of Henry. This technique may be associated with less morbidity including a shorter incision, decreased risk of medial plantar nerve injury, and decreased loss of lesser toe plantarflexion strength secondary to maintenance of the normal interconnections between the flexor hallucis longus (FHL) and FDL tendons.

Adolescent osteochondral lesion of the talus: Ankle arthroscopy in pediatric patients

Osteochondral lesions of the talus can be difficult to diagnose and can result in a significant functional limitation in young, active patients. New imaging modalities have improved the diagnosis and staging of these lesions. In general, nonoperative treatment results in poorer outcomes compared with operative treatment, and arthroscopic treatment has results similar to open treatment. Although the literature is limited, the treatment of adolescents results in outcomes similar to the adult population.

Biomechanical Evaluation of Calcaneocuboid Distraction Arthrodesis: A Cadaver Study of Two Different Fixation Methods

Calcaneocuboid distraction arthrodesis can be used to treat stage 2 posterior tibial tendon dysfunction. Nonunion, graft resorption, and implant failure have been reported after this procedure. This study compared two of the most commonly used methods for fixation of calcaneocuboid distraction arthrodesis. Twelve pairs of cadaver feet underwent simulated calcaneocuboid distraction arthrodesis. One specimen in each pair was fixed with two crossed 3.5 mm cortical lag screws. The contralateral specimen was fixed with a cervical H-plate. The calcaneus was fixed and a load was applied to the plantar aspect of the cuboid at a rate of 5mm/minute until joint separation of 3mm or fracture occurred. The average applied load to failure at 1.0 mm of joint separation was 30.5 +/−11.6 N for the crossed screws and 77.7 +/− 36.4 N for the cervical H-plate (p = 0.001). The average stiffness at 1.0 mm of joint separation was 27.5 +/− 10.9 N/mm for the crossed screws and 43 +/− 21.2 N/mm for the cervical H-plate (p = 0.036). The higher stiffness and load to failure may account for the decreased nonunion rate noted anecdotally by some surgeons with H-plate fixation over crossed screw fixation for calcaneocuboid distraction arthrodesis.

Different faces of the triple arthrodesis.

Patients with severe pes planovalgus or cavovarus foot deformities who fail conservative treatment may require a triple arthrodesis. Modifying the triple arthrodesis to include extended bone wedge resections allows for improved correction. The goal of each procedure is to obtain a less painful, plantigrade foot, and to improve function. Additional hindfoot or midfoot osteotomies may be needed in the modified triple arthrodesis. Midfoot or forefoot cavus can be addressed with either the Japas, Cole, or Jahss osteotomies, as described above. Residual hindfoot valgus can be adequately corrected with a medial displacement osteotomy of the calcaneus. Residual hindfoot varus is preferably corrected through a lateral closing wedge calcaneal osteotomy. This allows for adequate correction without the need for bone graft or an extended medial incision in the area of the tibial neurovascular bundle. Good results have been obtained with these types of complicated reconstructive procedures.

When does the flat-top talus lesion occur in idiopathic clubfoot: evaluation with magnetic resonance imaging at three months of age.

Flat-top talus has been described as a pathologic change secondary to idiopathic clubfoot condition and/or as a direct result of nonoperative manipulation involving forced dorsiflexion and molding of the cartilaginous talus. No definitive study, however, on the etiology and the timing of the flat-top talus deformity has been performed to date. The authors evaluated the magnetic resonance images of eleven patients with idiopathic clubfoot deformities treated with 2 to 3 months of casting to assess if flattening of the talar dome occurred at this age with this amount of casting. All children were 3 months of age, were casted for a maximum of 2 to 3 months, and sedated before MRI examination. The images were evaluated for maximum talar head height, maximum talar body height, and deviation of the talar body from a perfect circle. Maximum talar head height ranged from 4 to 9 mm, maximum talar body height ranged from 6 to 10mm. Eight of the eleven had maximum talar body measurements 3 to 5mm greater than maximum talar head height. Three of the eleven patients had head and body size of equal proportion. Two of the eleven had a talar body that was within 1mm of a perfect circle. The remaining nine patients had perfectly round talar bodies. In the senior authors (RSD) experience with treating clubfeet, a substantial increase has been seen at operation in flat-top tali among children that were casted for more than 1 year before surgical correction, compared to children casted for 3 months before surgical correction. The current investigation indicated that although tali of children with clubfeet are abnormally shaped, the talar body remains larger than the talar head and maintains its roundness after two to three months of corrective casting. Maintenance of cast treatment for more than three months may lead to the flat-top talus deformity. The authors recommend surgical intervention following three months of failed manipulation and casting to prevent this deformity.