James D. Michelson
Johns Hopkins University
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Featured researches published by James D. Michelson.
Foot & Ankle International | 1994
James D. Michelson; Mark E. Easley; Fredrick M. Wigley; David B. Hellmann
The purpose of this study was to examine the prevalence of foot and ankle problems in 99 patients with clinically proven rheumatoid arthritis. Patients were recruited from outpatient rheumatology clinics; no attempt was made to select patients on the basis of the severity of their disease, duration of disease, or symptom constellation. Each patient was examined by an investigator utilizing a predesigned protocol to assess their functional status, functional capacity, and overall joint involvement. Ninety-three of 99 patients had complaints referable to the foot or ankle at some time since diagnosis of rheumatoid arthritis. Ankle problems were paramount in 42%, forefoot difficulties in 28%, and equal ankle and forefoot problems in another 14%. Only four patients had had any treatment involving foot orthotic devices or special shoe wear. The prevalence of foot and ankle symptoms was related to the duration of systemic illness, but was present in > 50% of patients at any time after diagnosis of rheumatoid arthritis. Patients with longstanding rheumatoid arthritis have a high prevalence of foot and ankle symptoms. Unlike previous reports, the present study found a high prevalence of ankle and hindfoot symptoms, as opposed to forefoot complaints. Despite this finding, the patients had been treated infrequently by either conservative nonoperative management directed at accommodating footwear or surgical intervention to favorably alter their foot and ankle mechanics.
Foot & Ankle International | 1992
Melvin H. Jahss; James D. Michelson; Panna Desai; Robert A. Kaye; Frederick J. Kummer; William Buschman; Frank Watkins; Steven Reich
Anatomical, histological, and histochemical studies were performed on normal and abnormal fat pads of the sole of cadaver feet. The fat pads were found to contain a significant nerve and blood supply separate from that to the surrounding musculature and skin. Pacinian corpuscles and free nerve endings within the fat were identified. Histological analysis indicated a meshwork of fibroelastic septae arranged in a closed-cell configuration. The mechanical consequences of this organization are discussed in the context of the weightbearing role of the fat pads of the feet. Alterations seen in dysvascular or senescent feet are consistent with the hypothesis that the septal anatomy of the fat pads is central to their cushioning function.
Foot & Ankle International | 1992
Stephen F. Conti; James D. Michelson; Melvin H. Jahss
A retrospective study of attenuated/ruptured posterior tibial tendons was conducted of all patients who underwent tendon reconstruction over a 4-year period. The study comprised 20 feet in 19 patients having an average age of 53.3 years, with an average follow-up of 2 years. Preoperative magnetic resonance images were taken and graded for assignment to one of three magnetic resonance imaging (MRI)-based groups. The surgical grade was determined intraoperatively based on a previously described classification scheme. No medical or rheumatologic conditions predisposing to failure could be identified. Failure was defined as postoperative progression of pain and deformity which required subsequent triple arthrodesis. There were six failures at an average of 14.7 months. Surgical evaluation was not correlated to outcome following reconstruction. MRI grading, however, was predictive of outcome. The superior sensitivity of MRI for detecting intramural degeneration in the posterior tibial tendon that was not obvious at surgery may explain why MRI is better than intraoperative tendon inspection for predicting the outcome of reconstructive surgery. Therefore, it may be helpful to obtain preoperative MRI when this particular reconstruction of the posterior tibial tendon is contemplated, since this provides the best measure of tendon integrity and appears to be the best predictor of clinical success after such surgery.
Foot & Ankle International | 1995
James D. Michelson; Mark E. Easley; Fredrick M. Wigley; David B. Hellmann
Although hindfoot pathology in rheumatoid arthritis is a significant cause of disability for patients, the etiology of the planovalgus deformity is controversial. The present study surveys 99 patients with clinically proven rheumatoid arthritis for the presence and severity of hindfoot pathology. Specific attention was directed at the function of the posterior tibial tendon, as disruption of this structure has been implicated by some investigators as a cause of hindfoot deformity in rheumatoid arthritis. Assessment of posterior tibial function was by manual testing using two different grading scales, as well as by examination for several signs associated with posterior tibial tendon dysfunction. Between 13% and 64% of the study population could be considered to have posterior tibial tendon dysfunction, depending upon the specific diagnostic criteria used. Using the presence of all three of the most stringent criteria for diagnosis, 11% of patients were believed to have posterior tibial tendon dysfunction. These criteria were loss of the longitudinal arch, inability to perform a heel-rise, and lack of a palpable posterior tibial tendon. This study demonstrates that planovalgus deformity in rheumatoid arthritis can be due to clinically evident dysfunction of the posterior tibial muscle-tendon unit. There is a complex interplay between hindfoot joint disruption due to the inflammatory process and deformity due to tendinous dysfunction. If there is primary subtalar joint instability secondary to the inflammatory process, the posterior tibial tendon is rendered dysfunctional due to deranged hindfoot mechanics, as with primary posterior tibial tendon rupture. Since treatment of either condition (i.e., primary hindfoot instability or primary posterior tibial tendon rupture) is similar, the distinction is not important clinically. What is important is that attention to the specific cause of planovalgus would be expected to improve the overall treatment of rheumatoid feet.
Foot & Ankle International | 1991
Hugh J. Clarke; James D. Michelson; Quentin G.K. Cox; Riyaz H. Jinnah
A dynamic weight-bearing model has been developed in a cadaveric ankle model to assess the contact areas of the talus in varying degrees of bimalleolar ankle fractures. A surgically created transverse fibula osteotomy with up to 6 mm of displacement did not cause a significant change in the contact area. Sectioning of the deltoid ligament, regardless of fibular displacement, created a 15% to 20% decrease in the contact area (P < .001). This model represents a clinically relevant situation, as it examines motion of an unconstrained, axillary loaded ankle. Additional medial side disruption increases ankle instability by allowing anterior and lateral translation of the talus out of the mortise. Isolated lateral malleolar displacement does not appear to cause ankle instability.
Foot & Ankle International | 1992
Melvin H. Jahss; Frederick J. Kummer; James D. Michelson
The fat pads of the heel have a structure that is optimized for load bearing. In various diseases and aging, the load-carrying ability of the heel pad is clinically impaired. The loading pattern was examined in subjects having normal heel pads and those with atrophic heel pads, both with and without clinical symptoms. Normal heel pads showed a broad region of high pressure, which accounted for a high percentage of the total load transmission. In contrast, the atrophic heels showed a high but narrow peak pressure. However, most of the load was transmitted over a large area of low pressure. There was no difference between symptomatic and asymptomatic heels. The mechanical behavior of the fat pad is discussed with particular reference to the anatomic structure of the pads. Pad thickness and septal integrity are both important to the mechanical characteristics of the fat pad. The load-bearing patterns observed are discussed in terms of the mechanical components influencing fat pad resilience. These results have direct relevance to understanding the pathophysiology of heel pain secondary to degeneration of the fat pad.
Journal of Trauma-injury Infection and Critical Care | 1992
James D. Michelson; Donna Magid; Derek R. Ney; Elliot K. Fishman
A prospective study of the translational and rotational displacement of the lateral malleolus in ankle fractures was carried out utilizing roentgenographic techniques. Twenty-six ankle fractures in 25 patients were studied using both routine plain films and CT scanning with two- and three-dimensional multiplanar reconstruction. Eighty-one percent were Lauge-Hansen supination-external rotation type injuries. Overall, 21 fractures did not involve the medial malleolus. Initial talar shift was less than or equal to 2 mm in 15 fractures. Although all patients exhibited external rotation deformities of the lateral malleolus on plain films, only one fracture was found to possess any degree of external rotation relative to the talus. The proximal fibula was seen on CT scans to have increased internal rotation with respect to the tibia in 19 cases. One patient had a slightly externally rotated proximal fibula; the remainder appeared normally aligned. The displacements measured by the CT scans at the talofibular articulation were compared with the standard plain film measurements. The displacements at the distal lateral malleolus were consistently overestimated by the plain roentgenograms, presumably because the capsular and ligamentous attachments to the distal fibula limit malleolar displacement. The talocrural angle, determined on both plain films and CT scans, was also not found to be a sensitive measure of fibular shortening nor of the severity of the fracture. The results of this study suggest that, in an isolated lateral malleolar ankle fracture, the apparent external rotation of the fracture fragment is relative only to the proximal fibula and is not associated with derangement of the talofibular articulation. Based on these mechanical considerations, surgical intervention for such fractures may not be necessary. This hypothesis is consistent with previous long-term clinical studies.
Acta Orthopaedica Scandinavica | 1992
Mark J. Curtis; James D. Michelson; Marc W. Urquhart; Ronald P. Byank; Riyaz H. Jinnah
Six cadaveric ankles were dissected, preserving medial and lateral ligaments; an axial load of 455N was applied to the tibia supported by the foot and ankle. The unconstrained tibia was moved through 20 degrees of flexion and extension to simulate walking. The tibiotalar contact area was defined using carbon black suspension, recorded photographically, and measured using computerized area analysis. Osteotomy of the distal fibula was performed and fixed with a specially modified plate; a selection of plates provided fixation with 0 degrees or 30 degrees of external rotation in combination with 0 or 2 mm of shortening. The contact area was measured for each of the plates and after division of the deltoid ligament. There were greater than 30 percent decreases in tibiotalar contact with both fibular shortening and external rotation, doubled with a divided deltoid ligament. Anatomic restoration of both fibular length and rotation is essential for normal ankle mechanics. The deltoid ligament has crucial effects on the stability of the ankle mortise.
Foot & Ankle International | 2002
James D. Michelson; D. M. Durant; E. McFarland
Despite the common prophylactic use of rigid orthotics in athletes with flat feet to prevent subsequent injury, there is little scientific data in the literature examining the relationship between pes planus and athletic injuries to the lower extremity. The current prospective study was undertaken to establish what relationship, if any, exists between foot morphology and subsequent lower extremity injury. A total of 196 subjects were enrolled in the study, of which 143 (73%) were male and 53 (27%) were female. Forty-two percent of the participants (83) engaged in contact sports. There were a total of 227 episodes of injury involving the lower extremity. Logistic regression using contact sports, gender, and all of the different foot contact areas that were measured at the beginning of the study was undertaken. Although gender and participation in contact sports was predictive of some lower extremity injuries, the existence of pes planus as measured by medial midfoot contact area as a percentage of total contact area was not a risk factor for any injury of the lower extremity. This study shows that in an athletic population that is representative of collegiate athletics, the existence of flat footedness does not predispose to subsequent lower extremity injury. The routine prophylactic use of orthotics in flat-footed athletes to prevent future injury may therefore not be justified based on the data available.
Foot & Ankle International | 2005
James D. Michelson; Laura Dunn
Background: Symptoms associated with flexor hallucis longus (FHL) pathology can manifest themselves anywhere along its length from the posterior leg to the plantar foot and the hallux. This study describes the spectrum of clinical presentations seen with FHL pathology, illustrates the relevant physical examination findings, and outlines a treatment approach. Materials: Computerized medical data was prospectively collected on 81 patients treated between January, 1997 and March, 2002. The 55 females and 26 males had an average age of 38.3 years, with a mean follow-up of 21.3 months. Forty-five of 81 had previous therapy that failed, usually for “plantar fasciitis.” Twenty-seven were active athletically and 24 related the onset of symptoms to a specific traumatic episode. Pain was located at the posteromedial ankle in 40, plantar heel in 23, plantar midfoot in 22, and multiple locations in 16. All patients had tenderness of the FHL. Restriction of FHL excursion was demonstrated in 30 patients by limited hallux metatarsophalangeal joint dorsiflexion when the ankle was dorsiflexed (“FHL stretch test”). Thirty-four patients had magnetic resonance imaging of the FHL, 28 (82%) of which were positive for synovitis of the FHL. Treatment included an FHL stretching program, short-term immobilization, and operative decompression and synovectomy in patients for whom nonoperative treatment failed. Results: Of the 58 patients treated nonoperatively, 37 (64%) had successful results. Twenty-three patients had surgery, 20 at the posterior ankle fibro-osseous tunnel, and three in the sesamoid region. All patients treated operatively had successful outcomes. A subset of 10 patients had hallux rigidus symptoms without significant osteophyte formation. All 10 obtained successful results with treatment directed at restoring normal FHL excursion (nine nonoperatively, one by FHL release). This suggests that limited FHL excursion may be an etiology for the development of hallux rigidus. Conclusions: Clinical syndromes related to the FHL are more frequent than previously reported. The close relationship of the FHL to commonly injured structures (such as the plantar fascia) contributes to significant delays in effective treatment.