Michael J. Shereff

Associated injuries found in chronic lateral ankle instability.

Sixty-one patients underwent a primary ankle lateral ligament reconstruction for chronic instability between 1989 and 1996. In addition to the ligament reconstruction, all patients had evaluation of the peroneal retinaculum, peroneal tendon inspection by routine opening of the tendon sheath, and ankle joint inspection by arthrotomy. A retrospective review of the clinical history, physical exam, MRI examination, and intraoperative findings was conducted on these 61 patients. The purpose was to determine the type and frequency of associated injuries found at surgery and during the preoperative evaluation. At surgery no patients were found to have isolated lateral ligament injury. Fifteen different associated injuries were noted. The injuries found most often by direct inspection included: peroneal tenosynovitis, 47/61 patients (77%); anterolateral impingement lesion, 41/61 (67%); attenuated peroneal retinaculum, 33/61 (54%); and ankle synovitis, 30/61 (49%). Other less common but significant associated injuries included: intra-articular loose body, 16/61 (26%); peroneus brevis tear, 15/61 (25%); talus osteochondral lesion, 14/61 (23%); medial ankle tendon tenosynovitis, 3/61 (5%). The findings of this study indicate there is a high frequency of associated injuries in patients with chronic lateral ankle instability. Peroneal tendon and retinacular pathology, as well as anterolateral impingement lesions, occur most often. A high index of suspicion for possible associated injuries may result in more consistent outcomes with nonoperative and operative treatment of patients with chronic lateral ankle instability.

Kinematics of the first metatarsophalangeal joint.

The kinematics of both the first metatarsophalangeal joint and the articulation of the hallux sesamoid bones with the metatarsal head were investigated with fifteen fresh-frozen below-the-knee amputation specimens using a radiographic technique. Six feet were of normal structural anatomy, six displayed hallux valgus, and three had hallux rigidus. Normal specimens demonstrated an average total range of motion in the sagittal plane of 111 degrees, with about 76 degrees of dorsiflexion and 34 degrees of plantar flexion. The abnormal specimens revealed a decreased total arc of motion, with a limitation of plantar flexion in feet with hallux valgus and a loss of dorsiflexion in feet with hallux rigidus. Motion analysis of the normal metatarsophalangeal joints demonstrated minimum scattering of instant centers of rotation. This was in contrast to the diseased articulations, which displayed markedly displaced instant centers of rotation located eccentrically about the metatarsal head. Surface motion in the normal joints was characterized as tangential sliding from maximum plantar flexion to moderate dorsiflexion, with some compression at maximum dorsiflexion. The feet with hallux valgus and the feet with hallux rigidus displayed distinctive patterns of distraction and jamming throughout specific portions of the range of motion in the sagittal plane. Motion of the metatarsophalangeal joint in the transverse plane concomitant with motion in the sagittal plane, which has been hypothesized by other investigators, was confirmed and quantified in this study. The feet with hallux rigidus displayed a reduction in this motion.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro determination of midfoot motion.

Midfoot motion was determined using an in vitro model. Ten fresh-frozen below-the-knee amputation specimens were instrumented by inserting reference pins into each of the bones of the hindfoot, midfoot and metatarsals. Dorsiflexion-plantar flexion and supination-pronation were simulated and the reference pin location in three dimensional space was determined. Comparing the location of the reference pins at each simulated position, motion was determined. Motion occurring through each articulation (dorsiflexion-plantar flexion/supination-pronation) in degrees was: talonavicular (7.0/17.7), calcaneocuboid (2.3/ 7.3), naviculo-medial cuneiform (5.0/7.3), naviculo-middle cuneiform (5.2/3.5), naviculo-lateral cuneiform (2.6/2.1), medial cuneiform-first metatarsal (3.5/1.5), middle cuneiform-second metatarsal (0.6/1.2), lateral cuneiform-third metatarsal (1.6/2.6), cuboid-fourth metatarsal (9.6/11.1), and cuboid-fifth metatarsal (10.2/9.0).

Open Versus Arthroscopic Ankle Arthrodesis: A Comparative Study

A retrospective review was undertaken for 36 patients who underwent ankle arthrodesis. Nineteen patients underwent an arthroscopic ankle arthrodesis, and 17 patients underwent an open arthrodesis. Only patients with limited angular deformities were suitable candidates for an arthroscopic arthrodesis. The open arthrodesis group inclusion criteria were defined by the maximum coronal and sagittal plane deformity in the arthroscopic group. Perioperative parameters were compared and analyzed. Arthroscopic ankle arthrodesis yielded comparable fusion rates to open ankle arthrodesis, with significantly less morbidity, shorter operative times, shorter tourniquet times, less blood loss, and shorter hospital stays. Arthroscopic ankle arthrodesis is a valid alternative to traditional open arthrodesis of the ankle for selected patients with ankle arthritis.

Vascular Anatomy of the Fifth Metatarsal

The extraosseous and intraosseous vascular anatomy to the fifth metatarsal as visualized in a group of below-the- knee amputation specimens has been described. The extrinsic circulation to the area is provided by the dorsal metatarsal artery, the plantar metatarsal arteries, and the fibular plantar marginal artery. These three source arteries supply branches to the metatarsal and adjacent joints. The intraosseous vascularity consists of a periosteal plexus, a nutrient artery, and a system of metaphyseal and capital vessels.

Posterior Tibial Tendon Dysfunction: Its Association with Seronegative Inflammatory Disease:

Idiopathic inflammation and rupture of the posterior tibial tendon (PTT) has received much attention in the recent literature. In this report of the presentation of PTT dysfunction as a manifestation of seronegative inflammatory disease, we describe the clinical and laboratory features of 76 patients with inflammation and/or rupture of the PTT. Analysis of all patients identified two discrete groups. Group A patients were younger (mean age 39 years) and had multiple manifestations of inflammation at other sites of ligament and tendon attachments (enthesopathy). Other features of a systemic inflammatory disorder such as oral ulcers, conjunctivitis, colitis, and especially psoriasis were common in the latter patients and their families. Group B consisted predominantly of elderly patients (mean age 64 years) with isolated dysfunction of the PTT. These two groups differed widely in the manner of clinical presentation, demographic data, family history, HLA data, and surgical pathology. These distinctions suggest different pathogeneses for posterior tibial tendinitis. Group A demonstrated local manifestations of a systemic inflammatory disease, whereas group B exhibited the effects of mechanical trauma and degeneration.

A Comparison Study of Plantar Foot Pressure in a Standardized Shoe, Total Contact Cast, and Prefabricated Pneumatic Walking Brace

Total contact casting is the current recommended treatment for Wagner Stage 1 and 2 neuropathic plantar ulcers. The rationale for this treatment includes the equalization of plantar foot pressures and generalized unweighting of the foot through a total contact fit at the calf. Total contact casting requires meticulous technique and multiple cast applications to avoid complications before ulcer healing. An alternative to total contact casting is the use of a prefabricated brace designed to maintain a total contact fit. This study compares plantar foot pressure metrics in a standardized shoe (SS), total contact cast (TCC), and prefabricated pneumatic walking brace (PPWB). Five plantar foot sensors (Interlink Electronics, Santa Barbara, CA) were placed at the first, third, and fifth metatarsal heads, fifth metatarsal base, and midplantar heel of 10 healthy male subjects. Each subject walked at a constant speed over a distance of 280 meters in a SS, PPWB, and TCC. A custom-made portable microprocessor-based system, with demonstrated accuracy and reliability, was used to acquire the data. No significant differences in peak pressure or contact duration were found between the initial and repeat SS trials (P > 0.05). Peak pressures were reduced in the PPWB as compared to the SS for all sensor locations (P < 0.05). Similarly, peak pressures were reduced in the TCC compared to the SS for all sensor locations (P < 0.05) with the exception of the fifth metatarsal base (P = 0.45). Our results are summarized as follows: (1) the methods used in the current study were found to be reliable through a test-retest analysis; (2) the PPWB decreased peak plantar foot pressures to an equal or greater degree than the TCC in all tested locations of the forefoot, midfoot, and hindfoot; (3) compared to a SS, contact durations were increased in both the TCC and PPWB for most sensor locations; and (4) the relationship of peak pressure over time, the pressure-time integral, is lower in the brace compared to the shoe at the majority of sensor locations. The values are not significantly different between the cast and shoe. These findings suggest an unweighting of the plantar foot and equalization of plantar foot pressures with both the PPWB and TCC. Based on these findings, the PPWB may be useful in the treatment of neuropathic plantar ulcerations of the foot.

Prospective Study of Bone, lndium-111-Labeled White Blood Cell, and Gallium-67 Scanning for the Evaluation of Osteomyelitis in the Diabetic Foot

Twenty-two adult diabetic patients with clinical suspicion of foot and/or ankle infection were prospectively evaluated using radiography, technetium-99m methylene diphosphonate bone scanning (99Tc), indium-111-labeled leukocyte scanning (111In), and gallium-67 scanning (67Ga) to determine the presence of clinically suspected osteomyelitis. Biopsy for culture and histology was performed in 16 patients. The diagnosis of osteomyelitis was confirmed by biopsy in 12 patients. The remaining 10 patients had no evidence of osteomyelitis with long-term follow-up. 99mTc was snown to be of limited valued when used alone in these patients with peripheral neuropathy. 67Ga, either alone or in combination with 99mTc bone scanning, was of little diagnostic value and gave no additional information that was not available from 111In. The combination of three-phase 99mTc and 111In had the highest diagnostic efficacy (100% sensitivity, 80% specificity, and 91% accuracy), followed closely by 111In alone (100% sensitivity, 70% specificity, and 86% accuracy). We conclude that for adult diabetic patients with clinical suspicion of osteomyelitis but no radiographic findings of that disease, 111In alone is an appropriate nuclear medicine evaluation for ruling out infection if it is negative. However, if an area of 111In white blood cell uptake is present, a “simultaneous” 99mTc is often helpful in providing the anatomic correlation to differentiate osteomyelitis from infection that is limited to soft tissue.

The Stability of Fixation of First Metatarsal Osteotomies

Five different types of osteotomies for the correction of the hallux valgus deformity were performed on dried human first metatarsal bones. These included the step-cut Mitchell osteotomy, a distal transverse osteotomy, a distal biplanar osteotomy, the Chevron osteotomy, and a basilar osteotomy. Each type of procedure was then fixed using a variety of clinically appropriate techniques including single K-wires, crossed K-wires, a single A-0 cancellous screw, a single A-0 cortical screw, and three different types of sutures. Specimens were placed in a test jig and physiological loads applied with a Materials Testing Systems servohydraulic testing machine (Minneapolis, Minnesota). No difference in stability was observed between the various types of osteotomies, except for the Chevron osteotomy, which did possess greater inherent stability. Fixation by screws or multiple K-wires provided the most stable configuration when compared to other methods. The postoperative regimen following first metatarsal osteotomy should take into account the relative stability of fixation. Cast immobilization and a nonweight-bearing status may be preferable after procedures characterized by less mechanical stability.

Multistep Measurement of Plantar Pressure Alterations Using Metatarsal Pads

Metatarsal pads are frequently prescribed for nonoperative management of metatarsalgia due to various etiologies. When appropriately placed, they are effective in reducing pressures under the metatarsal heads on the plantar surface of the foot. Despite the positive clinical reports that have been cited, there are no quantitative studies documenting the load redistribution effects of these pads during multiple step usage within the shoe environment. The objective of this study was to assess changes in plantar pressure metrics resulting from pad use. Ten normal adult male subjects were tested during a series of 400-step trials. Pressures were recorded from eight discrete plantar locations at the hindfoot, midfoot, and forefoot regions of the insole. Significant increases in peak pressures, contact durations, and pressure-time integrals were noted at the metatarsal shaft region with pad use (P ≤ .05). Statistically significant changes in metric values were not seen at the other plantar locations, although metatarsal pad use resulted in mild decreases in mean peak pressures at the first and second metatarsal heads and slight increases laterally. Contact durations decreased at all metatarsal head locations, while pressure-time integrals decreased at the first, second, third, and fourth metatarsal heads. A slight increase in pressure-time integrals was seen at the fifth metatarsal head. The redistribution of plantar pressures tended to relate not only to the dimensions of the metatarsal pads, but also to foot size, anatomic foot configuration, and pad location. Knowledge of these parameters, along with careful control of pad dimensions and placement, allows use of the metatarsal pad as an effective orthotic device for redistributing forefoot plantar pressures.