Biomedical subjects
Publications and source records attributed to C L Saltzman.
The human foot is a unique structure in the animal kingdom, as it is capable of supporting sustained bipedal gait. The foot facilitates upright walking in several ways: 1) load bearing, 2) leverage, 3) shock absorption, 4) balance, and 5) protection. In this article, we discuss the specialized architecture that enables the foot to accomplish these functions.
Aligning an articulated ankle external fixator with the ankle axis located using a mechanical axis finder has been shown to preserve normal ankle joint kinematics while the fixed hinge device is attached. However, several problems exist preventing the clinical application of this finding for fractures of the tibial plafond. We initiated a series of studies to resolve these issues. First, the accuracy of the mechanical axis finder in biological systems was quantified by comparing it to that of a computationally derived helical axis. Second, a prototype fixator design was developed in the biomechanics lab to increase the versatility of intraoperative fixator placement. Finally, a radiographic method of locating the ankle axis was developed which is based on talar morphology independent of the fractured tibia. The prototype fixator has been accurately aligned along the ankle axis in cadaveric specimens using this method. Open reduction and internal fixation (ORIF) is the accepted method of treatment for tibial plafond fractures. It holds the advantage of sufficient fracture fixation to permit early joint motion. Good results have been reported using this method, but some authors have reported complication rates up to 50%. The wide surgical approaches required, in conjunction with preexisting soft tissue injury, are thought to significantly increase the risk of soft tissue complications. In response to these problems, many investigators are beginning to utilize external fixation as an alternate treatment modality. One external fixation system which has shown particularly good results is a monolateral cross-ankle articulated fixator (Orthofix SRL., Verona, Italy) which allows motion at the ankle joint as the plafond fracture is healing (Figure 1).(ABSTRACT TRUNCATED AT 250 WORDS)
The purpose of this study was to evaluate the efficacy of a leather ankle lacer for treating painful problems of the ankle and hindfoot. The evaluation involved patient self assessment, clinical examination and radiographic determination of the effectiveness of the ankle lacer. Overall, patients had moderate pain relief with significant but not complete restriction of motion. Based on this study and our clinical experience, we find the leather ankle lacer to be a compliant and comfortable treatment strategy for patients with painful ankle and hindfoot problems who desire some retained motion.
More people of all ages are now spending more time participating in sports, both competitive and recreational. This increase in participation has been accompanied by an increase in the number of tendon injuries. Tendons can also be injured during trauma, as part of degenerative disease and with chronic overuse. Magnetic resonance imaging (MRI) has greatly improved the ability to detect and characterize these injuries. The MRI appearance of several important tendons, in both the normal state and after injury of various types, is described and depicted in this review.
We reviewed six free flap reconstructions of the weight-bearing surface of the heel. Patients were seen for clinical evaluation at a mean follow-up of 4.7 years (range 2.7-6.0 years). Functional results using a modified Boston Children's Hospital Ankle Score were 33% excellent, 33% good, 17% fair, and 17% poor. The excellent functional results were related to the absence of chronic draining flap ulcers. All flaps lacked protective sensation by Semmes-Weinstein monofilament testing. Weightbearing plantar pressures in the flaps were elevated in all patients. Sequential radiographs from the time of flap coverage revealed the development of a bony protuberance (stalactite) projecting from the undersurface of the calcaneus in all patients with injuries to the plantar cortex of the calcaneus. In patients with flap ulceration, these stalactites projected into the ulcer at the site of maximum plantar pressure. A combination of loss of plantar calcaneal integrity, elevated pressure concentrations, and flap insensitivity appear causally related to the development of heel free flap ulceration and outcome.
In this cadaver study, the functional significance of the hallux sesamoid bones was quantified by measuring the effective tendon moment arm (ETMA) of the flexor hallucis brevis (FHB) force. (The ETMA differs from the anatomic tendon moment arm in that ETMAs are determined by the experimentally measured moment of the tendon force, rather than by the actual location and orientation of the tendon pull in the joint). The intact case was compared with three levels of progressive sesamoid resection: distal half of the medial sesamoid excised, entire medial sesamoid excised, and both the medial and lateral sesamoids excised. Five dorsiflexion angles of the metatarsophalangeal joint were tested, ranging from -10 degrees to 50 degrees. A known active load was applied to the FHB muscle of fresh frozen cadaver specimens while the corresponding resisting forces from three orthogonally mounted transducers were being recorded. Results showed that the ETMAs decreased significantly (P < .05) only with the excision of both sesamoids. The percent decrease in ETMA was smallest at dorsiflexion angles of -10 degrees and 15 degrees (4.3% and 2.4%, respectively) and largest at dorsiflexion angles of 25 degrees, 35 degrees, and 50 degrees (29.2%, 22.4%, and 26.7%, respectively). The clinical significance of the results is that distal hemiresection of the medial sesamoid or full medial sesamoid excision is unlikely to appreciably compromise the effective mechanical advantage of the FHB muscle. However, this mechanical advantage may be profoundly diminished by excision of both hallux sesamoids.
A laboratory study was undertaken to quantify the validity, the intra- and interobserver reliability, and the effect of first metatarsal orientation on the distal metatarsal articular angle (DMAA). First metatarsals from six cadavers were isolated by sharp dissection and attached to a custom-made triplanar protractor. This allowed controlled positioning of the first metatarsal in the three cardinal planes. Each specimen was moved through a stepwise sequence of first metatarsal orientation changes. Radiographs were taken at each position. The distal (metatarsophalangeal) articular surface of the first metatarsal was then circumscribed with metallic paint and the radiographic series was repeated. DMAA measurements were made on each radiograph multiple times by two measurers blinded to the parameters of variation. The difference between the standard (clinical) radiographic technique for estimating the DMAA and the metallic paint DMAA averaged -0.9 degrees (SD = 2.4 degrees). Longitudinal rotation (P < .0001) and varus deviation (P < .02 at 10 degrees) of the first metatarsal had a significant effect on the radiographic determination of the DMAA. Although intraobserver reliability for DMAA measurement was high, interobserver reliability for the clinical technique of measurement was poor (pooled intraclass correlation coefficient = 0.14).
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The chevron osteotomy for hallux valgus was modified by addition of screw fixation and change of the osteotomy angle. Thirty-six patients underwent this modified osteotomy. All had mild to moderate symptomatic hallux valgus deformities. No other forefoot procedures were performed. Standing radiographs were taken before surgery, at 1 month after surgery, and, for the 15 patients who returned for long-term follow-up, at 1 year or more after surgery. Overall, 35/42 procedures were rated as satisfactory without reservations and 7 were rated as satisfactory with mild reservations. All patients stated that they had some improvement in their preoperative symptoms, which included pain, cosmetic concerns, and shoe wear difficulties. Radiographically, none of the capital fragments displaced and there were no malunions, nonunions, nor evidence of avascular necrosis. The average metatarsophalangeal-1 angle improved 8 degrees and the average intermetatarsal 1-2 angle improved 4 degrees. This modification is relatively simple, increases stability, and allows early weightbearing. In our experience, the modified chevron osteotomy has been a very reliable procedure for mild to moderate symptomatic hallux valgus deformity.
Fifty standing dorsoplantar and lateral foot radiographs were obtained on a consecutive series of patients seen in an orthopaedic foot and ankle clinic. These radiographs were duplicated, and eight common foot measurements were made on each pair by six experienced examiners. Measurements were made in two ways: first by a subjective visual assessment, and second by quantitative evaluation made according to strictly defined criteria. All measurements were made under controlled, ideal conditions with similar high quality goniometers. The results demonstrated overall greater reliability in the quantitative methods than the non-quantitative methods. For each of the quantitative techniques, a cumulated frequency distribution of differences between examiners was calculated. The approximate 95% bounds for these measures were: hallux-metatarsophalangeal angle = 6 degrees, first intermetatarsal angle = 4 degrees, metatarsophalangeal-5 angle = 11 degrees, fourth intermetatarsal angle = 4 degrees, AP talocalcaneal angle = 20 degrees, lateral talocalcaneal angle = 12 degrees, sesamoid station = 2 grades, and forefoot width = 5 mm. Physicians using these parameters to make decisions regarding patient care and clinical outcomes need to keep in mind these potential errors in making foot radiographic measurements.
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Stress fractures are overuse injuries of bone. Basketball players are particularly prone to develop the notoriously "troublesome" stress fractures of the foot and leg. This article reviews the pathogenesis, epidemiology, diagnosis, and treatment of stress fractures, with specific emphasis on the care of the basketball athlete.
UNLABELLED: The effects of shoe wear, custom-made inserts, patellar tendon-bearing (PTB) braces, and extra-padded PTB braces on load transmission to neuroarthropathic (Charcot) feet of six diabetic patients were assessed. A PTB brace with a free ankle and an extradepth shoe without external modifications was used. Four distinct anatomical regions were evaluated by an in-shoe technique measuring vertical force. The mean peak force transmitted to the entire foot was higher in the affected than in the unaffected extremity barefoot and shod. The mean peak forces under the midfoot were higher for the affected than for the unaffected extremity for all tested circumstances. In the affected foot, use of the standard PTB brace reduced mean peak force to the entire foot by 15%. Adding extra padding to the brace decreased the mean peak force 32%. The effect of padding on vertical load transmission was greatest for patients who had worn the brace the longest. For the patients who had worn it longer than average, the addition of padding decreased the mean peak force to the entire foot by 19%, to the hindfoot by 37%, and to the midfoot by 20%. CLINICAL RELEVANCE: In this preliminary study, we found that a properly fitted PTB brace can reduce load transmission to the Charcot foot. Specifically, load transmission was reduced to the hindfoot, but not to the midfoot or forefoot. Based on these results, we cannot recommend its use to reduce vertical force transmission to the Charcot midfoot or forefoot. Long-term PTB brace use, especially in the limited weight-bearing patient, should be regularly adjusted to ensure adequate brace fit.
Insertion of distal interlocking screws in femoral nails can be technically demanding and may entail substantial exposure. A method of insertion of femoral interlocking screws that uses a laser guiding system in addition to the standard image intensifier was used in an attempt to improve the accuracy of distal screw placement and to limit radiation exposure. Using this technique, 97% of the distal femoral drill holes attempted were successfully made with the first pass of a drill. Little or no resistance to the drill was met from contacting the femoral nail. Average fluoroscopy time was 0.4 minute. Laser-assisted screw placement requires relatively inexpensive modifications of existing equipment and is easy to master. Compared with the more commonly used freehand method, laser-assisted screw placement appears to offer a reduction in the amount of time and radiation exposure required to insert distal interlocking femoral screws.
We studied 366 feet in 313 patients who underwent surgical treatment for a primary interdigital neuroma through a dorsal web-splitting incision. Three hundred five feet in 259 patients were available for follow up, which averaged 5.9 years (range: 2.8 to 13); 45.2% of these patients were completely satisfied, 33.8% were satisfied with minor reservations, 9.2% were satisfied with major reservations, and 11.8% were dissatisfied after the surgical procedure. Patient satisfaction was directly related to the size of the neuroma found at the time of operation. Bilateral procedures were associated with a higher rate of dissatisfaction. The third web space accounted for 91% of the neuromas.
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