Foot & Ankle International

Background: Little has been reported about the biologic effect of shock waves on human normal or pathologic tendon tissue. We hypothesized that inflammatory cytokine and MMP production would be down-regulated by shock wave stimulation. Materials and Methods: Diseased Achilles tendon tissue and healthy flexor hallucis longus tissue were used. Shock wave treatment was applied to cultured cells at 0.17 mJ/mm²energy 250, 500, 1000, and 2000 times. Results: A dose-dependent decrease in cell viability was noted in cells receiving 1000 and 2000 shocks (86.0 ± 5.6%, p = 0.01 and 72.4 ± 8.9%, p = 0.001) as compared with the normal control. Cell count in the 500-shock group increased by 23.4% as compared with the control (p = 0.05). The concentration of MMP 1, 2, and 13 was higher in diseased tenocytes as compared with normal cells (p = 0.04, all comparisons). IL-6 levels were higher in the diseased tenocytes as compared with normal tenocytes (44.10 ± 16.72 versus 0.21 ± 0.55 ng/ml, (p < 0.05). IL-1 levels in normal cells increased (2.24 ± 5.02 ng/ml to 9.31 ± 6.85 ng/ml) after shock wave treatment (p = 0.04). In diseased tenocytes, levels of MMP-1 (1.12 ± 0.23 to 0.75 ± 0.24 ng/ml; p = 0.04) and MMP-13 (1.43 ± 0.11 to 0.80 ± 0.15 ng/ml; p = 0.04) were significantly decreased after shock wave treatment. The IL-6 level in diseased tenocytes was decreased (44.10 ± 16.72 to 14.66 ± 9.49 ng/ml) after shock wave treatment (p = 0.04). Conclusion: Higher levels of MMPs and ILs were found in human tendinopathy-affected tenocytes as compared with normal cells. ESWT decreased the expression of several MMPs and ILs. Clinical Relevance: This mechanism may play an important role in shock wave treatment of tendinopathy clinically.

Purpose: The purpose of this study was to retrospectively evaluate the clinical and radiographic outcomes of the medium and long-term results of Bionx bioabsorbable screw fixation of the ankle syndesmosis in unstable ankle injuries. Materials and Materials: Between May 2001 and July 2006, 75 patients underwent syndesmotic fixation with a bioabsorbable screw. All patients had closed primary ankle fractures or dislocations with syndesmotic instability. Open reduction and internal fixation of the ankle fracture was performed using current standard orthopaedic technique. Patients were followed clinically and radiographically from 12 to 74 months with the mean being 32.5 months. Results: Seventy of 75 patients (93%) returned for the final evaluation. Mean AOFAS Ankle-Hindfoot score was 90 of 100 and mean VAS for pain was 1.8 out of 10 at the time of final followup. No patients in this population showed radiographic syndesmotic instability, loss of mortise congruency, or post-traumatic arthritis in the sigmoid notch area at final followup. No patients required revision surgical fixation of the syndesmosis. Conclusion: This study demonstrates that the use of bioabsorbable screw for syndesmotic fixation is associated with satisfactory restoration of ankle function and syndesmotic stability.

Background: An accessory navicular bone may cause pain due to continuous irritation at its interface with the navicular. The authors performed the fusion of the accessory navicular and navicular with screw(s) to relieve the symptoms while preserving the continuity of the posterior tibial tendon. Materials and Methods: We analyzed the clinical and radiological outcomes of 31 consecutive patients (34 feet) with a painful type II accessory navicular. Results: Bone union was confirmed on plain radiography in 28 (82%) of 34 feet. Twenty-two patients (24 feet) were assessed as excellent, two (three feet) as good, and one (one foot) as fair. Nonunion developed in six patients (six feet) and was defined as poor. Conclusion: When conservative treatment fails to relieve pain in a type II accessory navicular, fusion of the accessory navicular to the navicular may successfully relieve pain without disrupting the tibialis posterior tendon insertion.

Background: Ankle and subtalar stiffness are widely associated with many foot and ankle conditions and functional deficits. Loss of range of motion, particularly dorsiflexion, results in significant gait dysfunction. A variety of methods have been evaluated to address this problem, including yoga, manipulation, dance training, jogging and static stretching exercises. No tools have been described that effectively and efficiently stretch the ankle and subtalar joint without requiring supervision or assistance of a trained physical therapist. Materials and Methods: Twenty-two subjects with varying foot and ankle diagnoses who had little or no improvement in range of motion after traditional assisted physical therapy were recruited from a foot and ankle orthopaedic clinic. The subjects'ankle and subtalar range of motion (ROM) in plantarflexion (PF), dorsiflexion (DF), inversion (INV), and eversion (EVR) were measured using a standard goniometer by a single physiotherapist prior to using the stretching device. The subjects were trained on the proper use of the stretching device and then instructed to use it daily for a 6-week period. Then the same examiner repeated the above measurements. Statistical analysis was performed using a two sample t-test assuming unequal variances. Results: There were statistically significant increases in ROM in all planes tested: DF to PF (p = 0.0052), and INV to EVR (p = 0.018). Conclusion: Stretching with the device significantly increased ankle and subtalar ROM. Clinical Significance: The stretching device can be used at home on a regular basis with minimal training and can effectively treat stiffness of the ankle and subtalar joints. It can be cost-effective when compared to use of physiotherapy services.

Background: Degenerative arthritis of the hallux metatarsophalangeal (MTP) joint can be treated in a variety of ways depending on the severity of the disease. If nonoperative treatment fails, then surgical treatment of Stage I and II has traditionally been cheilectomy. The purpose of this paper was to determine the potential advantages of cheilectomy using a less conventional dorsolateral approach. Materials and Methods: Twenty feet in 20 patients were included in the study with an average age of 53.8 (range, 29 to 69) years. The average followup was 2.8 years. Patient charts and radiographs were reviewed to determine preoperative patient characteristics and clinical-radiographic stage. All patients who qualified for the study were asked to return for evaluation using clinical examination, radiographs, and the AOFAS outcome score. Comparisons were made between preoperative and postoperative values using appropriate statistical analysis. Results: The mean AOFAS score improved from 53.5 to 84.0 (p < 0.001). The mean range of motion arc improved from 45 to 58 degrees (p < 0.001). Clinical-radiographic stage progressed in 50%. The most common complication was numbness in the first web space (40%). This loss was imperceptible in all patients until asked during the exam. No patients progressed to fusion during the followup period. Conclusion: Using a dorsolateral approach to perform a cheilectomy is a viable alternative to the more traditional dorsal technique. No obvious advantage over the traditional technique was identified.

Background: Hallux valgus surgery has been performed on only one side, even though patients may have bilateral hallux valgus. This study evaluated the results of simultaneous surgical correction for bilateral hallux valgus compared with unilateral correction. Materials and Methods: A retrospective review of 52 patients (69 feet) that underwent proximal metatarsal chevron osteotomy and distal soft tissue procedure for moderate to severe hallux valgus was conducted. Minimum followup was at least 12 months. Patients were divided into two groups, simultaneous bilateral surgical group (Group A) and a unilateral surgical group (Group B). Group A comprised 34 feet in 17 women and Group B comprised 35 feet in 35 women. Results: Average AOFAS scores were 57.0 points in group A and 52.8 points in group B preoperatively and at the last followup improved to 93.4 points and 92.2 points, respectively. Very satisfied or satisfied levels of patient satisfaction were 94.1% in Group A and 91.4% in Group B. Average hallux valgus angles in Groups A and B changed from 34.8 degrees and 37.9 degrees preoperatively to 12.5 degrees and 12.4 degrees postoperatively, respectively. Intermetatarsal 1-2 angles in Groups A and B changed from an average of 15.7 degrees and 18.4 degrees preoperatively to 7.4 degrees and 7.1 degrees postoperatively, respectively. No significant inter-group differences were observed in clinical and radiographic outcomes. Conclusions: Based on our results, the results of simultaneous bilateral correction for hallux valgus deformity was not worse than a unilateral correction. We advocate simultaneous correction for bilateral hallux valgus requiring surgical correction.

Background: Diabetic patients with Charcot arthropathy of the foot are at high risk for nonunion when undergoing arthrodesis. There is increasing evidence that cytokines identified in platelet rich concentrate and bone marrow aspirate may show equivalence to autologous bone graft in supporting arthrodesis. Materials and Methods: Prospectively, 44 high-risk diabetic patients with Charcot foot arthropathy underwent surgical correction of 46 feet through a limited surgical approach. The average age of the patients was 54.9 ± 10.4 years. Their mean BMI was 38.0 ± 9.7. Twenty-four were male and 20 were female. Twenty-eight had open wounds with chronic draining osteomyelitis. Surgical correction was maintained postoperatively with static circular ring fixation. At the time of wound closure, all of the patients had injection of autologous platelet rich concentrate and bone marrow aspirate. Results: Forty-two of the 46 feet had radiographic evidence of bony union at 26.2 ± 12.2 months following surgery. One patient died of unrelated causes. Two underwent amputation for persistent infection. Six had recurrent ulcers which resolved with local treatment. One patient required a fifth ray resection for gangrene following surgery. There were three tibial stress fractures, with two requiring intramedullary nailing to achieve union. Conclusions: Platelet-rich concentrate, when combined with a small amount of autologous bone marrow aspirate, may well be as effective as autologous bone grafting when performing arthrodesis of high risk diabetic patients with Charcot foot arthropathy.

Background: We devised a method of sclerotherapy using OK432. The present study comprised a retrospective followup of sclerotherapy outcomes. Materials and Methods: Eighteen feet in 18 consecutive patients (seven men, 11 women; mean age, 55 years) were treated with sclerotherapy. Previous surgery had been performed one to four times for seven feet. After aspirating the contents of the ganglion cysts, 0.2 to 0.3 ml of suspension of OK432 (lyophilized strep pyogenes) was injected. The volume of fluid aspirated was from 0.2 to 2.5 ml, with an average of 0.9 ml. Mean duration of followup was 3 years 6 months. Clinical evaluation was performed using the AOFAS hallux scale. Results: All ganglion cysts disappeared after sclerotherapy. However, recurrences were observed in eight feet. Mean duration until recurrence was 13 months. Sclerotherapy was again performed for all patients with recurrence. Re-recurrence occurred in three feet. A third sclerotherapy was performed for all three patients. All ganglion cysts had disappeared by final followup. Mean AOFAS score improved from 75 points before therapy to 95 points at followup. Six patients had complications with local redness and pain for 1 to 6 days after injection. Conclusion: Sclerotherapy using OK432 is a minimally invasive treatment of symptomatic ganglion cysts of the hallux. Recurrence is common but complications are infrequent and self-limited.

Background: Clinical outcomes of subtalar arthrodesis using screw fixation have been reported but biomechanical support for selection of screw trajectories and patterns has been lacking. This investigation was designed to assess the compressive and stabilizing abilities of different common screw insertion patterns for subtalar arthrodesis. Materials and Methods: Forty-two cadaveric subtalar joints underwent arthrodesis with a single talar neck screw, a single talar dome screw, double parallel screws, or double diverging screws. Single talar dome screw fixation was subdivided by screw tip placement in the anteromedial, posteromedial, anterolateral, or posterolateral dome. Joint compression, construct torsional stiffness, and joint angulation under torsional load were quantified. Results: Higher compressive force, torsional stiffness, and joint rotation resistance were achieved by double screw fixation compared to single screws (p < 0.001). Torsional stiffness with double diverging screws exceeded that of double parallel screws in internal rotation (p < 0.05). There was greater internal rotation with a single talar neck screw (p < 0.001) and greater external rotation with an anterolateral talar dome screw (p < 0.01) compared to the other single-screw orientations. Greater rotation in both directions was noted with the single screw tip located in the posterolateral talar dome (p < 0.01). Conclusion: Under the described testing conditions, double diverging screws confer the highest compression, the greatest torsional stiffness, and the least joint rotation. When a single screw is used, placement of the screw tip in the talar neck or lateral talar dome should be avoided. Clinical Relevance: The results provide an objective basis for selection of optimal screw placement by the surgeon.

Background: Hallux valgus associated with metatarus primus varus is a deformity that disrupts normal foot function. Standard treatment has often included distal or proximal metatarsal osteotomy with or without a distal soft tissue procedure. The intrinsically unstable proximal crescentic osteotomy relies on operative fixation for stability. This study examined the strength of fixation of a single screw versus a plate for stabilization of proximal first metatarsal crescentic osteotomies for correction of hallux valgus. Materials and Methods: A crescentic osteotomy was performed on nine pairs of fresh/frozen cadaveric feet. The distal fragment was rotated laterally and the osteotomy was temporarily stabilized with a Kirschner wire. The osteotomized metatarsal fragments were fixed with a cancellous screw on one side and single plate on the contralateral side. Each specimen was loaded in a mechanical testing machine, and its response was measured by monitoring the opening of the osteotomy and change in alignment of the fragments. Position and alignment of the proximal and distal fragments were calculated. Results: All of the measures of fixation strength were statistically greater in specimens treated with a plate rather than with screw fixation. Plate fixation provided approximately twice the resistance to disruption of the osteotomy under cyclic loading conditions. Conclusion: The dorsal plate is biomechanically more stable than a single cancellous screw when applied to proximal crescentic osteotomies. Clinical Relevance: The greater stability of the plate construct may be helpful in selecting the fixation device for these osteotomies.

Background: Talonavicular fusion is performed for a variety of indications. This study examined the effects of fixation techniques on plantar pressures, construct stiffness, and strength. Materials and Methods: Eight matched pairs of cadaveric lower extremities were axially loaded intact and after talonavicular fixation with a 3.5 reconstruction plate, reconstruction plate plus cancellous screw (plate/screw), or three screws (screws). Recorded plantar pressures were divided into three forefoot, two midfoot, and two hindfoot regions. Cantilevered bending of excised constructs provided stiffness data for plantar and lateral directions, and failure characteristics in plantar bending. Results: Relative to the intact state, all fixations decreased peak pressure in the medial forefoot, while generally increasing it in the lateral forefoot and midfoot. Average pressure shifted laterally for all fixation methods in the forefoot, generally in the hindfoot and the lateral midfoot. Generally, contact areas decreased in the medial forefoot, midfoot, and hindfoot while increasing laterally in the midfoot and hindfoot. The only difference among fixation methods was a decreased medial midfoot contact area for screws. No differences were found between screws and plate/screw in bending stiffness or failure (p < 0.5 and p < 0.2 respectively). Plantar and lateral bending stiffness for the plate/screw method averaged approximately 363 N/mm while stiffness of the screw only construct averaged approximately 380 N/mm. The load to failure averaged 946 N for the plate/screw construct and 1099 N for the screw construct. Conclusion: This study showed lateralization of plantar pressures following talonavicular fixation. Minimal differences were found between plate/screw and screws. Fixation across the joint may be key to achieving stability sufficient to resist shear and rotational stresses. Clinical Relevance: Plate/screw or screws would likely be similarly effective in fusing the talonavicular joint. However, the fusion induced lateralization of plantar pressures may unintentionally result in adjacent joint arthritis and foot pain.

Background: Our goal was to quantify and visualize the three-dimensional loading relationship between the ligaments and articular surfaces of the ankle to identify and determine the stabilizing roles of these anatomical structures during the stance phase of gait. Materials and Methods: We applied discrete element analysis to computationally model the three-dimensional contact characteristics and ligament loading of the ankle joint. Physiologic loads approximating those at five positions in the stance phase of a normal walk cycle were applied. We analyzed joint contact pressures and periankle ligament tension concurrently. Results: Most ankle joint loading during the stance phase occurred across the articular surfaces of the joint, and the amount of ligament tension was small. The tibiotalar articulation showed full congruency throughout most of the stance phase, with peak pressure developing anteriorly toward the toe-off frame. Of the periankle ligaments, the deep deltoid ligament transferred the most force during the stance phase (57.2%); the superficial deltoid ligament transferred the second-most force (26.1%). The anterior talofibular ligament transferred force between the talus and fibula continuously, whereas the calcaneofibular ligament did not carry force during gait. The distal tibiofibular ligaments and the interosseous membrane were loaded throughout the stance phase. Conclusion: Force transmission through the ankle joint during the stance phase is predominantly through the articular surfaces, and the periankle ligaments do not play a major stabilizing role in constraining ankle motion. The medial ligaments have a more important role than do the lateral ligaments in stabilizing the ankle joint. Clinical Relevance: In addition to ligament insufficiency, other factors, such as varus tilt of the tibial plafond, may be important in the development of recurrent instability. Continuous loading of syndesmosis ligaments provides a theoretical basis for evidence of syndesmosis screw breakage or loosening. The analysis method has potential applications for clarifying ankle joint function and providing a basis for comparison between normal and abnormal joint conditions.