Biomedical subjects
Publications and source records attributed to M S Myerson.
Continued research and clinical advances have allowed clinicians to diagnose injuries of the tarsometatarsal joint earlier and with greater precision than in previous eras and have promoted refinements of the surgical procedures used in their treatment. For patients with such injuries, these advances should result in improved function and a substantial decrease in morbidity.
Numerous surgical procedures have been proposed for reconstructing and correcting adult flatfoot deformity. Most procedures include lengthening of the tight Achilles tendon and transferring the FDL tendon to substitute for a dysfunctional PTT. These procedures commonly are combined with a bone procedure to stabilize the correction and correct the pathologic anatomy. All of these procedures have the potential for a range of complications, many of them serious. In general, the clinician should perform the least invasive procedure that decreases pain and improves function. The effects of each procedure and the associated morbidity and complications must be considered.
For metatarsalgia caused by a dislocated lesser metatarsophalangeal (MTP) joint and isolated over-long lesser metatarsals, surgical treatment options without sacrificing the joint are limited. Recently, the Weil osteotomy has been advocated for the treatment of this deformity. In our experience, preliminary results with this technique have revealed a high rate of dorsiflexion contracture of the MTP joints at follow-up. We performed a cadaver study and a three-dimensional analysis on sawbones to investigate this phenomenon. In the cadaveric portion of this study, the second MTP joints of two fresh-frozen cadavers were dissected; the entire ray, with the metatarsal shaft, MTP joint, toe, and plantar fascia, was removed en bloc. After gross anatomic structures were photographed, a Weil osteotomy was performed at 25 degrees relative to the long axis of the metatarsal shaft. The positions of muscles, ligaments, and tendons were noted and photographed before and after the osteotomy. In the sawbones portion of this study, a Weil osteotomy was performed at four different angles (25 degrees, 30 degrees, 35 degrees, and 40 degrees) relative to the long axis of the metatarsal. To ensure reproducibility, the sawbone models were fixed proximally to a vertical milling machine with the second metatarsals inclined 15 degrees to simulate the anatomic position. After making the cut, the plantar fragment was translated along the dorsal fragment proximally for a distance of 5 mm. Before and after the osteotomy, selected x, y, and z coordinates were obtained using a Microscribe 3D digitizer. Data analysis was performed with Microsoft Excel, and ANOVA was used to determine significant differences (p < 0.05) between the various osteotomies. Analysis of the cadaver dissection revealed that after the Weil osteotomy, the tendons of the interosseous muscles move dorsally with respect to the axis of the MTP joint due to the depression of the plantar fragment of the metatarsal. The loss of their flexion effect on the joint permits the pull of the extensor to dorsiflex the toe. The size of the depression for the various osteotomies averaged: 25 degrees osteotomy, 3.03 mm (range, 1.8 to 3.8 mm); 30 degrees osteotomy, 3.2 mm (range, 1.9 to 4.0 mm); 35 degrees osteotomy, 3.5 mm (range, 1.7 to 5.7 mm); and 40 degrees osteotomy, 4.2 mm (range, 2.8 to 6.4 mm). Amounts of shortening relative to the long axis of the metatarsal for the various osteotomies averaged: 25 degrees osteotomy, 5.03 mm (range, 4.77 to 5.30 mm); 30 degrees osteotomy, 4.59 mm (range, 3.47 to 5.19 mm); 35 degrees osteotomy, 4.27 mm (range, 2.87 to 5.00 mm); and 40 degrees osteotomy, 3.65 mm (range, 3.20 to 4.31 mm). According to our analysis, depression of the plantar fragment always occurs after a Weil osteotomy. This depression changes the center of rotation of the MTP joint, and the interosseous muscles then act more as dorsiflexors than as plantarfexors.
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The goal of this study was to determine if the application of muscle forces (simulating the dynamic phase of the midstance part of gait) had an effect on flatfoot deformity. We created a flatfoot model in each of seven cadaver foot specimens by grasping the Achilles, peroneus longus, peroneus brevis, flexor digitorum longus, and flexor hallucis longus tendons with soft-tissue vice clamps connected via wire cables to pneumatic cylinders. The experiment included four stages: 1) initial static axial loading; 2) axial loading after 3,000 load cycles (average, 735 N; range, 70 to 1400 N); 3) axial loading after releasing the spring ligament and plantar fascia; and 4) axial loading after an additional 3,000 load cycles. At each stage, both static (with axial loading only) and dynamic (axial loading with tensioning of the tendons to simulate the muscle forces at midstance) conditions were evaluated radiographically. No change was observed between the static and dynamic conditions in the first two phases of the experiment. After the third phase, changes in the talar-first metatarsal angle and the height of the medial cuneiform were noted, particularly in the dynamic condition. These and additional radiographic changes were magnified in the fourth phase, but only in the dynamic condition. We concluded that, to create an effective flatfoot model, the medial structures, including the spring ligament and possibly the plantar fascia, must be severed. Cyclic loading of the foot further increased the arch flattening, and this effect was magnified by dynamic loading.
HYPOTHESES/PURPOSE: The success of the medial displacement calcaneal osteotomy in correcting flatfoot deformities is likely to be the result of a shift of the Achilles tendon forces on the hindfoot. The purpose of this study was twofold: 1) to define the contribution of the Achilles tendon to the flatfoot deformity, and 2) to define the effect of a calcaneal medial displacement osteotomy. METHODS: We used six different experimental dynamic stages: 1) intact foot without Achilles loading; 2) intact foot with Achilles loading; 3) flatfoot without medial calcaneal displacement osteotomy and without Achilles loading; 4) flatfoot without medial calcaneal displacement osteotomy but with Achilles loading; 5) flatfoot with medial calcaneal displacement osteotomy but without Achilles loading; and 6) flatfoot with medial calcaneal displacement osteotomy and with Achilles loading. The experimental flaffoot was developed by releasing the posterior tibial tendon, spring ligament, and plantar fascia and applying 7,000 cycles of axial fatigue load (range, 700 to 1,400 N; 1-Hz frequency). To simulate the phase of midstance, the peroneus longus, peroneus brevis, flexor digitorum longus, and flexor hallucis longus tendons were grasped by clamps, connected to pneumatic actuators, and loaded with precalculated forces. Anteroposterior and lateral radiographs were obtained for each stage on which the following measurements were made: talonavicular coverage angle, talar-first metatarsal angle, talocalcaneal angle, and height of the medial cuneiform. These measurements were compared with a one-way ANOVA. RESULTS: Between stages 1 and 2, all measurements were statistically insignificant. Between stages 3 and 4, for all measurements, Achilles tendon loading aggravated the flatfoot deformity (p < 0.05). After medial calcaneal osteotomy (stages 5 and 6), the Achilles tendon contributed less to the arch-flattening. We found that the medial displacement osteotomy plays an important role in reducing and/or delaying the progress of flatfoot deformity. CONCLUSIONS/SIGNIFICANCE: In the flatfoot, loading of the Achilles tendon increases the deformity. Medial calcaneal osteotomy significantly decreases the arch-flattening effect of this tendon and therefore limits the potential increase of the deformity.
This retrospective study analyses the results of subtalar bone block distraction arthrodesis used in the treatment of late complications of calcaneal fractures, acute severely comminuted fractures, nonunion (and malunion) of attempted subtalar arthrodeses, avascular necrosis of the talus, and club-foot deformity. Of 39 patients (41 feet) who had this procedure, 35 (37 feet) returned for follow-up after a mean of 70 months (26 to 140). There were 24 men (25 feet) and 11 women (12 feet) with a mean age of 41 years (16 to 63). Each completed a standardised questionnaire, based on the hindfoot-scoring system of the American Orthopaedic Foot and Ankle Society and were reviewed both clinically and radiologically. Of the 37 operations, 32 (87%) achieved union. The mean hindfoot score (maximum of 94 points) increased from 21.1 points (8 to 46) preoperatively to 68.9 (14 to 82) at the final follow-up. The mean talocalcaneal and calcaneal pitch angles were 20.5 degrees and 4.9 degrees before operation, 25.9 degrees and 8.3 degrees immediately after, and 24.6 degrees and 7.7 degrees at the final follow-up, respectively. The mean talar declination angle improved from 6.5 degrees (-10 to 22) before operation to 24.8 degrees (14 to 32) at the final follow-up. The mean talocalcaneal height increased from 68.7 mm before operation to 74.5 mm immediately after and 73.5 mm at the final follow-up. Of the 37 arthrodeses available for review, 32 were successful; 29 patients (30 arthrodeses) were satisfied with the procedure. Minimal loss of hindfoot alignment occurred when comparing radiographs taken immediately after operation and at final follow-up.
Because malunion (usually with dorsal elevation of the first metatarsal) has been reported after the treatment of severe hallux valgus deformities by proximal osteotomies, the current study was designed to compare the sagittal stability of six different metatarsal shaft osteotomies: the proximal crescentic, proximal chevron, Mau, Scarf, Ludloff, and biplanar closing wedge osteotomies. A plate was used in the biplanar closing wedge osteotomy; all others used screws for fixation. Ten fresh-frozen, human anatomic lower extremity specimens were used for each osteotomy. Failure loads were measured as units of force (newtons) and converted to pressure (kilopascals). Then the F-Scan system, which uses a thin insole to measure plantar pressure, was used to evaluate the pressure under the first metatarsal of seven volunteers using four types of shoes. According to the results, in patients with normal bone stock who are compliant, any of the four shoe types tested may be used after a Ludloff, Scarf, biplanar wedge (plantar screw fixation), or Mau osteotomy, but the wedge-based shoe should be used after a proximal crescentic or chevron osteotomy or for patients with severe osteopenic bone.
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We treated 24 patients (18 women, six men; average age, 46.4 years; (range, 28 to 66 years) with fusion of the hallux metatarsophalangeal (MTP) joint using bone graft for the restoration of the length of the first ray. This procedure was performed after bone loss subsequent to previous surgeries for the correction of hallux valgus and hallux rigidus with: silastic arthroplasty (11), bunionectomy and distal metatarsal osteotomy (six), Keller resection arthroplasty (five), and total joint replacement (two). The indication for performing the arthrodesis with bone graft was a short first metatarsal, and associated metatarsalgia of the lesser metatarsals in addition to a painful MTP joint with or without deformity. This bone loss was associated with avascular necrosis of the first metatarsal (nine patients) and with osteomyelitis (seven patients). Of the 24 patients, 14 underwent additional concurrent surgery for correction of hammer toes (10), excision of a Morton's neuroma (two), and lesser metatarsal osteotomy (two). All patients were examined clinically and radiographically at a mean interval of 62.7 months after surgery (range, 26 to 108 months). The patients were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) hallux and MTP 100-point outcome scale. Arthrodesis occurred in 19/24 patients (79.1%) at a mean of 13.3 weeks (range, 11 to 16 weeks), and the first ray was lengthened by a mean of 13 mm (range, 0 to 29 mm). Of the five nonunions, two were asymptomatic, and three were subsequently revised successfully, with arthrodesis occurring at a mean of 10.7 weeks. Complications included one deep infection requiring intravenous antibiotics for treatment of osteomyelitis and two minor superficial wound infections. The mean AOFAS score improved from 39 points (range, 22 to 60 points) to 79 points (range, 64 to 90 points). All patients were satisfied with the final outcome of treatment and stated that they would undergo the surgical procedure again. We concluded that arthrodesis of the hallux MTP joint with bone graft to restore bone loss and length of the first ray may be a worthwhile procedure despite the technical difficulty and the high rate of nonunion.
PURPOSE: The purpose of this investigation was to evaluate the outcome of tibiocalcaneal arthrodesis using an adolescent condylar blade plate for severe ankle and hindfoot deformities. MATERIALS AND METHODS: We retrospectively reviewed the records of patients managed at our institutions between 1989 and 1996 whose tibiocalcaneal arthrodeses were performed with adolescent condylar blade plates and allograft bone. In these 30 patients (14 men, 16 women; average age, 53 years), the etiologies of the nonbraceable deformity included: diabetic neuroarthropathy with talar fragmentation and resorption (26), inflammatory arthritis (3), and posttraumatic avascular necrosis of the talus with collapse (1). Due to the severity of the deformity in 28 of these patients, the alternative treatment would have been amputation. Thirteen patients had undergone previous surgeries, eight had documented osteomyelitis, and 13 had ulcers ranging from 2 to 27 mm. At surgery, the remnants of the talus were removed. Morcellized bone graft mixed with tobramycin/vancomycin powder was inserted into the arthrodesis site and then fixed with a rigid plate. Intravenous antibiotics, followed by oral antibiotics, were given until wound healing and suture removal. Follow-up averaged 48 months (19 to 112 months). RESULTS: Tibiocalcaneal fusion was achieved in 28/30 patients at an average of 16 weeks (12 to 18 weeks). Complications occurred in seven patients: two developed stress fractures of the tibia at the proximal end of the blade plate, three had superficial cellulitis that resolved with antibiotic therapy, and two had nonunions. CONCLUSION: Tibiocalcaneal arthrodesis using an adolescent condylar blade plate and allograft bone can be a successful procedure in the patient with severe neuropathic ankle deformity and can achieve a stable plantigrade foot for limited community ambulation with relatively few complications.
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BACKGROUND: To analyze the effects of multiple preoperative, intraoperative, and postoperative factors on the intermediate results of triple arthrodesis, we focused on preoperative deformity, preoperative diagnosis, degree of clinical and radiographic correction, and arthritis of the ankle. METHODS: Between 1987 and 1995, 160 patients were managed with a total of 183 triple arthrodeses. Patients who had an infection or neuroarthropathy or who were managed with a revision arthrodesis were excluded from our study. Of the 160 patients, 111 (132 feet) who had been followed for a minimum of two years formed our study group. Each patient had an arthrodesis with rigid screw fixation and realignment of the joint surfaces without resection of wedges. The average duration of follow-up was 5.7 years (range, 2.0 to 10.8 years). RESULTS: As seen radiographically, arthritis of the ankle was significantly more severe postoperatively than preoperatively (p<0.01), although patient satisfaction was not associated with the presence of arthritis. On a scale (not a visual analog) of 0 (not satisfied) to 10 (completely satisfied), overall satisfaction averaged 8.3 points (range, 0 to 10 points). The postoperative modified ankle-hindfoot score of the American Orthopaedic Foot and Ankle Society averaged 60.7 points (range, 0 to 94 points). There was a significant association (p = 0.001) between satisfaction of the patient and postoperative alignment. Ten patients had a total of eleven complications: four superficial wound problems, three nonunions, one case of superficial peroneal neuritis, one case of Charcot-like neuroarthropathy of the foot (in a patient in whom diabetes developed during the follow-up period), one rupture of the Achilles tendon, and one case of peroneal tenosynovitis. Of the 111 patients, 101 (91 percent) stated that they would have the procedure again under similar circumstances, and this response was independent of the preoperative diagnostic or deformity group. CONCLUSIONS: Triple arthrodesis for the treatment of various deformities and etiologies is effective in relieving pain and improving functional deficits. Although a high prevalence of subsequent arthritis of the ankle was noted clinically and radiographically, we could detect no association between satisfaction of the patient and arthritis.
BACKGROUND: The purposes of this retrospective study were to review the results of isolated subtalar arthrodesis in adults and to identify factors influencing the union rate. The hypotheses were that (1) the overall outcome is acceptable but is not as favorable as previously reported, (2) complication rates, especially the nonunion rate, are higher than previously reported, and (3) factors contributing to a less favorable union rate can be identified. METHODS: Between January 1988 and July 1995, 184 consecutive isolated subtalar arthrodeses were performed in 174 adults (115 men and fifty-nine women) whose average age was forty-three years (range, eighteen to seventy-nine years). Eighty patients (46 percent) were smokers. The indications for the procedure included posttraumatic arthritis after a fracture of the calcaneus (109 feet), a fracture of the talus (thirteen feet), or a subtalar dislocation (thirteen feet); primary subtalar arthritis (thirteen feet); failure of a previous subtalar arthrodesis (twenty-eight feet); and residual congenital deformity (eight feet). Rigid internal fixation with one or two screws was used for all feet. Bone graft was used in 145 feet; the types of graft material included cancellous autograft (ninety-four feet), structural autograft (twenty-nine feet), cancellous allograft (seventeen feet), and structural allograft (five feet). Bone graft was not used in the remaining thirty-nine feet. RESULTS: Clinical and radiographic follow-up examinations were performed for 148 (80 percent) of the 184 feet at an average of fifty-one months (range, twenty-four to 130 months) postoperatively. The average ankle-hindfoot score according to the modified scale of the American Orthopaedic Foot and Ankle Society (maximum possible score, 94 points) improved from 24 points preoperatively to 70 points at follow-up. Thirty feet had clinical evidence of nonunion. The union rate was 84 percent (154 of 184) overall, 86 percent (134 of 156) after primary arthrodesis, and 71 percent (twenty of twenty-eight) after revision arthrodesis. The union rate was 92 percent (ninety-three of 101 feet) for nonsmokers and 73 percent (sixty-one of eighty-three feet) for smokers (p < 0.05). Intraoperative inspection revealed that 42 percent (seventy-eight) of the 184 feet had evidence of more than two millimeters of avascular bone at the subtalar joint; all thirty nonunions occurred in this group (p < 0.05). A nonunion occurred in three of the five feet that had been treated with structural allograft and in two of the six feet in which the subtalar arthrodesis had been performed adjacent to the site of a previous ankle arthrodesis. After elimination of the subgroups of feet in patients who smoked, those that had had a failure of a previous subtalar arthrodesis, those that had been treated with a structural graft, and those that had had the subtalar arthrodesis adjacent to the site of a previous ankle arthrodesis, the union rate improved to 96 percent (seventy-three of seventy-six). Complications other than nonunion included prominent hardware requiring screw removal (thirty-six of 184 feet; 20 percent), lateral impingement (fifteen of 148 feet; 10 percent), symptomatic valgus malalignment (five of 148 feet; 3 percent), symptomatic varus malalignment (four of 148 feet; 3 percent), and infection (five of 184 feet; 3 percent). CONCLUSIONS: To the best of our knowledge, the present study includes the largest reported series of isolated subtalar arthrodeses in adults. Our results suggest that the outcome following isolated subtalar arthrodesis is not as favorable as has been reported in previous studies. The rate of union was significantly diminished by smoking, the presence of more than two millimeters of avascular bone at the arthrodesis site, and the failure of a previous subtalar arthrodesis (p < 0.05 for all). Other factors that probably affect the union rate include the use of structural allograft and performance of the arthrodesis adjac
To determine the effects of intermittent compression on foot swelling, intracompartmental pressures, and hospital stay associated with acute calcaneus fractures, we retrospectively reviewed the records of 55 patients between January 1990 and July 1992 whose management profile included preoperative use of an intermittent compression foot pump and surgical treatment by open reduction and internal fixation. Average times were: injury to admission, 6.04 days; admission to surgery, 1.35 days; and surgery to discharge, 3.38 days. Hospital stay averaged 4.73 days. In 27 patients with suspected compartmental ischemia, admission and preoperative pressures in three compartments were averaged and compared: 18.22 and 3.81 mm Hg, respectively (p < 0.001). The authors concluded that the intermittent compression pump appears to rapidly reduce swelling of the foot and decrease elevated compartment pressures associated with calcaneus fractures, which may play a role in decreasing hospital stay.
BACKGROUND: The chevron osteotomy, an accepted method for the correction of mild and moderate hallux valgus, is generally advocated for patients younger than the age of fifty years. The purposes of this prospective study were to compare the short-term (two-year) and intermediate-term (five-year) results of this operation with respect to patient satisfaction, flexion and extension of the metatarsophalangeal joint, maintenance of correction, and development of arthrosis and to determine whether the effectiveness of the procedure was limited by age. METHODS: Between April 1991 and September 1992, the chevron osteotomy was performed for the treatment of mild-to-moderate hallux valgus deformity in sixty-six consecutive feet. Forty-three patients (fifty-seven feet) were available for follow-up at both two and five years postoperatively. The two-year and five-year clinical assessments were based on the American Orthopaedic Foot and Ankle Society's hallux-metatarsophalangeal-interphalangeal scale. RESULTS: Between the two-year and five-year follow-up evaluations, there was only a minimal change in overall patient satisfaction, and the average score on the hallux-metatarsophalangeal-interphalangeal scale was unchanged. The passive range of motion of the first metatarsophalangeal joint decreased between the preoperative assessment and the two-year follow-up evaluation and was unchanged at the five-year follow-up evaluation. Radiographic evaluation showed no changes in the hallux valgus or intermetatarsal angle between the two-year and five-year evaluations, although the number of feet with arthrosis of the metatarsophalangeal joint increased slightly, from eight to eleven. Patients aged fifty years or older did as well as younger patients. CONCLUSIONS: At these two follow-up periods, the chevron osteotomy was found to be a reliable procedure for the correction of mild and moderate hallux valgus deformity, and outcome did not differ on the basis of age.
Hypermobility of the first ray is one of the causative components in common foot problems (such as hallux valgus) with a large intermetatarsal angle and metatarsus primus varus. Although not always associated with hallux valgus, hypermobility is a predisposing factor for this deformity, especially in conjunction with extrinsic factors, such as disruption of the plantar first metatarsal cuneiform ligament and tendon-muscle imbalance. Hypermobility is also frequently found in adolescents with hallux valgus, especially when associated with a large intermetatarsal angle. Motion at the first metatarsocuneiform joint occurs in the sagittal and transverse planes. Most studies agree that greater than 4 degrees and greater than 8 degrees, respectively, constitutes excessive motion. Clinically, hypermobility is evaluated by determining sagittal motion (the grasping test) and transverse motion (the clinical squeeze test) and by identifying signs such as the presence of a dorsal bunion, intractable plantar keratosis beneath the second metatarsal head, and arthritis of the first and second metatarsocuneiform joint. Radiographically, hypermobility is evaluated by measurements from the modified Coleman block test (for sagittal motion) and the radiographic squeeze test (for transverse motion) and by the identification of signs, such as cortical hypertrophy along the medial border of the second metatarsal shaft, a cuneiform split, the presence of os intermetatarseum, and the round shape and increased medial slope of the first metatarsocuneiform joint. Usually, treatment for hypermobility of the first ray is operative, but surgery is contraindicated for patients less than 20 years of age (especially when the epiphysis is not closed) and for patients with generalized ligamentous laxity, short first metatarsal, and arthritis of the hallux MTP joint. The authors' surgical treatment of choice is arthrodesis of the tarsometatarsal joint (as part of the hallux valgus correction), exostectomy, capsulorraphy, and distal soft tissue release to correct and stabilize the first metatarsal at the apex of the deformity. The authors have found it unnecessary to include the base of the second metatarsal. The main complications associated with the Lapidus procedure and its modifications are nonunion, malunion, and dorsal elevation of the first metatarsal. Although radiographic nonunion is the most frequent complication, only 25% of the patients with this condition have associated clinical findings; the results have been defined as good or excellent in two series. These results closely equal those in rheumatoid or sedentary patients managed with newer, modified, less traumatic techniques that stabilize the first metatarsocuneiform joint with screws rather than with arthrodesis.