Marcus P. Besser

Osteochondral Lesions of the Talus: Localization and Morphologic Data from 424 Patients Using a Novel Anatomical Grid Scheme

Background: The primary aim of this study was to evaluate the true incidence of osteochondral lesions on the talar dome by location and by morphologic characteristics on MRI. Because no universally accepted localization system for talar dome osteochondral lesions currently exists, we established a novel, nine-zone anatomical grid system on the talar dome for an accurate depiction of lesion location. Methods: We assigned nine zones to the talar dome articular surface in an equal 3 × 3 grid configuration. Zone 1 was the most anterior and medial, zone 3 was anterior and lateral, zone 7 was most posterior and medial, and zone 9 was the most posterior and lateral. The grid was designed with all nine zones being equal in surface area. Two observers reviewed MRI examinations of 428 ankles in 424 patients (211 males and 213 females; mean age 43 years; age range 6 to 85 years) with reported osteochondral talar lesions. We recorded the frequency of involvement and size of lesion for each zone. Statistical analyses were performed using ANOVA and Scheffe tests. Results: Four hundred and twenty-eight lesions were identified on MRI. The medial talar dome was more frequently involved (n = 269, 62%) than the lateral talar dome (n = 143, 34%). In the AP direction, the mid talar dome (equator) was much more frequently involved (n = 345, 80%) than the anterior (n = 25, 6%) or posterior (n = 58, 14%) thirds of the talar dome. Zone 4 (medial and mid) was most frequently involved (n = 227, 53%), and zone 6 (lateral and mid) was second most frequently involved (n = 110, 26%). Lesions in the medial third of the talar dome were significantly larger in surface area involvement and deeper than those at the lateral talar dome. Conclusions: Our established nine-grid scheme is a useful tool for localizing and characterizing osteochondral talar lesions, which are most frequently located in zone 4 at the medial talar dome, and second most in zone 6 at the lateral talar dome near its equator. Medial talar dome lesions are not only more common but are larger in surface area and in depth than lateral lesions. Posteromedial and anterolateral lesions rarely were found.

Test-retest reliability of temporal and spatial gait characteristics measured with an instrumented walkway system (GAITRite).

BackgroundThe purpose of this study was to determine the test-retest reliability of temporal and spatial gait measurements over a one-week period as measured using an instrumented walkway system (GAITRite®).MethodsSubjects were tested on two occasions one week apart. Measurements were made at preferred and fast walking speeds using the GAITRite® system. Measurements tested included walking speed, step length, stride length, base of support, step time, stride time, swing time, stance time, single and double support times, and toe in-toe out angle.ResultsTwenty-one healthy subjects participated in this study. The group consisted of 12 men and 9 women, with an average age of 34 years (range: 19 – 59 years). At preferred walking speed, all gait measurements had ICCs of 0.92 and higher, except base of support which had an ICC of 0.80. At fast walking speed all gait measurements had ICCs above 0.89 except base of support (ICC = 0.79),ConclusionsSpatial-temporal gait measurements demonstrate good to excellent test-retest reliability over a one-week time span.

Comparison of an in-shoe pressure measurement device to a force plate: concurrent validity of center of pressure measurements.

The purpose of this study was to assess the concurrent validity of center of pressure (COP) measurements during walking, comparing the Parotec System (an in-shoe pressure measurement device) to an Advanced Mechanical Technology Inc. (AMTI) force plate. Pearson correlation coefficients comparing COP displacement in the medial-lateral (ML) and anterior-posterior (AP) direction calculated from the two systems were greater than 0.70 for 52/67 trials (78%) in the ML direction and were greater than 0.90 for 67/67 trials (100%) in the AP direction. The mean root mean square (RMS) error for COP displacement in the ML direction was 0.56+/-0.3 cm and in the AP direction was 1.37+/-0.59 cm. Overall, the Parotec System showed good correlation and small RMS errors when compared to the AMTI force plate. Additional analysis to investigate sources of error pointed to the methods used for calculating the position and orientation of the subjects foot on the force plate. Subsequent analysis to eliminate some of these errors, compared force calculated from the Parotec System and the AMTI plate and showed good to excellent correlation (>0.70) for 62/67 trials (93%). Additional data were collected that allowed for elimination of methodological errors. Again force calculated from the two systems was compared using Pearsons. These data showed excellent correlation (>0.90) for 20/20 trials (100%). This study provides evidence of the validity of the Parotec System for measuring COP during ambulation.

Validity of the Dexter Evaluation System's Jamar Dynamometer Attachment for Assessment of Hand Grip Strength in a Normal Population

There are several instruments available to measure grip strength, but some instruments are costly, time-consuming to use, or have questionable reliability. The purpose of this study is to examine the concurrent validity of the Dexter Evaluation System with Jamar dynamometer attachment (Dexter) compared with the reference-based criterion of the Jamar adjustable hand dynamometer (Jamar) for measurement of maximal hand grip strength among normal subjects. Sixty-two subjects between the ages of 20 and 50 years, who had no history of hand, arm, shoulder, or neck injuries, were tested with the Jamar in the second handle position and, during the same visit, with the Dexter in the identical position. The Jamar was found to be highly reliable (ICC [3,1] = 0.98) and valid (ICC (2,K) = 0.99) for measuring hand grip strength. In this study, the Dexter was shown to be valid when compared to the Jamar dynamometer for measuring hand grip strength.

Prediction of Midfoot Instability in the Subtle Lisfranc Injury: Comparison of Magnetic Resonance Imaging with Intraoperative Findings

BACKGROUND The objective of the present study was to assess the utility of magnetic resonance imaging for the diagnosis of an injury to the Lisfranc and adjacent ligaments and to determine whether conventional magnetic resonance imaging is a reliable diagnostic tool, with manual stress radiographic evaluation with the patient under anesthesia and surgical findings being used as a reference standard. METHODS Magnetic resonance images of twenty-one feet in twenty patients (ten women and ten men with a mean age of 33.6 years [range, twenty to fifty-six years]) were evaluated with regard to the integrity of the dorsal and plantar bundles of the Lisfranc ligament, the plantar tarsal-metatarsal ligaments, and the medial-middle cuneiform ligament. Furthermore, the presence of fluid along the first metatarsal base and the presence of fractures also were evaluated. Radiographic observations were compared with intraoperative findings with respect to the stability of the Lisfranc joint, and logistic regression was used to find the best predictors of Lisfranc joint instability. RESULTS Intraoperatively, seventeen unstable and four stable Lisfranc joints were identified. The strongest predictor of instability was disruption of the plantar ligament between the first cuneiform and the bases of the second and third metatarsals (the pC1-M2M3 ligament), with a sensitivity, specificity, and positive predictive value of 94%, 75%, and 94%, respectively. Nineteen (90%) of the twenty-one Lisfranc joint complexes were correctly classified on magnetic resonance imaging; in one case an intraoperatively stable Lisfranc joint complex was interpreted as unstable on magnetic resonance imaging, and in another case an intraoperatively unstable Lisfranc joint complex was interpreted as stable on magnetic resonance imaging. The majority (eighteen) of the twenty-one feet demonstrated disruption of the second plantar tarsal-metatarsal ligament, which had little clinical correlation with instability. CONCLUSIONS Magnetic resonance imaging is accurate for detecting traumatic injury of the Lisfranc ligament and for predicting Lisfranc joint complex instability when the plantar Lisfranc ligament bundle is used as a predictor. Rupture or grade-2 sprain of the plantar ligament between the first cuneiform and the bases of the second and third metatarsals is highly suggestive of an unstable midfoot, for which surgical stabilization has been recommended. The appearance of a normal ligament is suggestive of a stable midfoot, and documentation of its integrity may obviate the need for a manual stress radiographic evaluation under anesthesia for a patient with equivocal clinical and radiographic examinations.

Reconstruction for Missed or Neglected Achilles Tendon Rupture with V-Y Lengthening and Flexor Hallucis Longus Tendon Transfer through One Incision

Background: The purpose of this study was to introduce a novel operative technique and to evaluate the clinical outcomes in a cohort of patients with missed or neglected Achilles tendon ruptures. Methods: Fifteen consecutive patients with missed complete Achilles tendon ruptures and 5-cm or larger gaps had reconstruction with V-Y lengthening and flexor hallucis longus tendon transfer through a single incision. The patients were evaluated at an average of 106 weeks after surgery. At the time of followup, all patients were assessed with regard to their self-reported level of satisfaction and the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale. Ankle strength and active range of motion were evaluated using Biodex® (Biodex Medical Systems, Shirley, NY) isokinetic dynamometry. In addition, seven patients were evaluated using diagnostic ultrasound. Results: We found a 7.7 N-m (–22.3%) loss of plantarflexion torque at 60 degrees/sec and a 3.5 N-m (–13.5%) loss of plantarflexion torque at 120 degrees/sec, as well as a 5 degrees loss of active range of motion. AOFAS scores were all good to excellent, with an average score of 94.1 of 100. All patients were satisfied with their outcomes (rated good or very good). Excellent exposure of the Achilles tendon repair was obtained with ultrasound. Conclusions: For patients with missed or neglected Achilles tendon rupture with a rupture gap of at least 5 cm, operative repair using V-Y lengthening and flexor hallucis longus tendon transfer through a single incision technique achieved a high percentage of satisfactory results.

Outcomes of Chronic Insertional Achilles Tendinosis Using FHL Autograft Through Single Incision

Background: The purpose of this study was to evaluate the clinical outcomes and objective isokinetic dynamometry on a cohort of patients with chronic insertional Achilles tendinosis, who underwent surgical reconstruction using an FHL tendon autograft transfer through a single incision. Materials and Methods: Forty patients (16 male and 24 female; mean age, 57 years; age range, 39 to 76 years) with persistent chronic Achilles tendinosis were evaluated after surgical reconstruction at an average of 27 months after surgery. At the time of final followup, ankle strength and active range of motion (AROM) were evaluated using Biodex® isokinetic dynamometry. Additionally, patients were assessed with AOFAS Ankle Hindfoot scores, pain on a Visual Analog Scale (VAS) and their self-reported level of satisfaction (Very Good, Good, Fair, Poor). Results: We found no loss of plantarflexion strength or plantarflexion power in the operated ankles; an average of 4-degree loss of AROM was found. The study population scored an average of 96/100 for the total AOFAS-AH score post-repair. The average VAS decreased from 7.5 pre-op to 0.3 post-op. Thirty-eight of 40 patients (95%) were satisfied with their outcome (rated Very Good or Good), two patients rated their outcome as Fair and none as Poor. Conclusion: For individuals with chronic insertional Achilles tendinosis, operative repair using an FHL tendon with the single-incision technique achieved a high percentage of satisfactory results as well as excellent functional and clinical outcomes including significant pain reduction. Level of Evidence: IV, Retrospective Case Study

Osteochondral Lesions of the Distal Tibial Plafond: Localization and Morphologic Characteristics with an Anatomical Grid:

Background: The aim of this study was to evaluate the incidence and morphologic characteristics of osteochondral lesions of the distal tibial plafond (OLTP) by location and morphologic characteristics on MRI. Material and Methods: We assigned 9 zones to the distal tibial plafond articular surface in an equal 3×3 grid configuration. Zone 1 was the most anterior and medial, zone 3 was anterior and lateral, zone 7 was most posterior and medial, and zone 9 was the most posterior and lateral. The grid was designed with all 9 zones being equal in surface area. Two observers reviewed MRI examinations of 38 patients (12 males and 26 females; mean age, 38.7 years; age range, 10 to 68 years) with reported OLTPs. We recorded the frequency of involvement and size of lesion for each zone. A chart review was performed. Results: Of the 38 OLTP found in this study, 14 (37%) of the lesions were on the medial tibial plafond [zones 1, 4 and 7] and 11 (29%) involved the lateral tibial plafond [zones 3, 6 and 9]; 13 lesions (34%) localized to the center third of the plafond [zones 2, 5 and 8]. Nine of the lesions (24%) were on the anterior tibial plafond [zones 1, 2 and 3], 15 lesions (39%) predominately involved the posterior plafond [zones 7, 8 and 9], and 14 lesions (37%) localized to the central third of the plafond [zones 4, 5 and 6]. The medial central tibial plafond was most frequently involved site with 8 of the 38 (21%) lesions located there; the posterior medial tibial plafond was second most frequently involved with six of the 38 lesions (16%). Six of 38 ankles had both a talar osteochondral lesion and an OLTP. Of these, only one was a ‘kissing’ lesion. Chart review revealed that all subjects had ankle pain at time of MRI examination. Conclusion: We conclude that osteochondral lesions of the distal tibial plafond must be considered in the differential diagnosis of patients with symptomatic ankles and that no location had a significantly higher incidence.

Bone stress injury of the ankle in professional ballet dancers seen on MRI

BackgroundBallet Dancers have been shown to have a relatively high incidence of stress fractures of the foot and ankle. It was our objective to examine MR imaging patterns of bone marrow edema (BME) in the ankles of high performance professional ballet dancers, to evaluate clinical relevance.MethodsMR Imaging was performed on 12 ankles of 11 active professional ballet dancers (6 female, 5 male; mean age 24 years, range 19 to 32). Individuals were imaged on a 0.2 T or 1.5 T MRI units. Images were evaluated by two musculoskeletal radiologists and one orthopaedic surgeon in consensus for location and pattern of bone marrow edema. In order to control for recognized sources of bone marrow edema, images were also reviewed for presence of osseous, ligamentous, tendinous and cartilage injuries. Statistical analysis was performed to assess the strength of the correlation between bone marrow edema and ankle pain.ResultsBone marrow edema was seen only in the talus, and was a common finding, observed in nine of the twelve ankles imaged (75%) and was associated with pain in all cases. On fluid-sensitive sequences, bone marrow edema was ill-defined and centered in the talar neck or body, although in three cases it extended to the talar dome. No apparent gender predilection was noted. No occult stress fracture could be diagnosed. A moderately strong correlation (phi = 0.77, p= 0.0054) was found between edema and pain in the study population.ConclusionBone marrow edema seems to be a specific MRI finding in the talus of professional ballet dancers, likely related to biomechanical stress reactions, due to their frequently performed unique maneuvers. Clinically, this condition may indicate a sign of a bone stress injury of the ankle.

Mounting and calibration of stairs on piezoelectric force platforms

Abstract To calculate the centre of pressure using piezoelectric force plates mounted on pads, no net tensile stresses may be imposed on the surface of the plate. This condition is violated when stairs are attached to the plates, unless the plates are preloaded. Typical shear forces encountered when climbing stairs were used to determine required preloads of approximately 16.4 N/cm step height. Vertical and horizontal loads were applied at known locations on the steps, and points of application were calculated. Deviations were within ± 3 mm. The effect of point of application inaccuracy on calculated joint moments is considerable. A 2 cm medial shift in the point of application resulted in calculated peak knee abduction/adduction moment errors of 35%.