In vitro assessment of the motion of equine proximal sesamoid bones relative to the third metacarpal bone under physiologic midstance loads.

OBJECTIVE: To assess the motion of the proximal sesamoid bones (PSBs) relative to the third metacarpal bone (MC3) of equine forelimbs during physiologic midstance loads. SAMPLE: 8 musculoskeletally normal forelimbs (7 right and 1 left) from 8 adult equine cadavers. PROCEDURES: Each forelimb was harvested at the mid-radius level and mounted in a material testing system so the hoof could be moved in a dorsal direction while the radius and MC3 remained vertical. The PSBs were instrumented with 2 linear variable differential transformers to record movement between the 2 bones. The limb was sequentially loaded at a displacement rate of 5 mm/s from 500 N to each of 4 loads (1.8 [standing], 3.6 [walking], 4.5 [trotting], and 10.5 [galloping] kN), held at the designated load for 30 seconds while lateromedial radiographs were obtained, and then unloaded back to 500 N. The position of the PSBs relative to the transverse ridge of the MC3 condyle and angle of the metacarpophalangeal (fetlock) joint were measured on each radiograph. RESULTS: The distal edge of the PSBs moved distal to the transverse ridge of the MC3 condyle at 10.5 kN (gallop) but not at lower loads. The palmar surfaces of the PSBs rotated away from each other during fetlock joint extension, and the amount of rotation increased with load. CONCLUSIONS AND CLINICAL RELEVANCE: At loads consistent with a high-speed gallop, PSB translations may create an articular incongruity and abnormal bone stress distribution that contribute to focal subchondral bone lesions and PSB fracture in racehorses.

Effect of metatarsal osteotomy and open lateral soft tissue procedure on sesamoid position: radiological assessment.

BACKGROUND: Incomplete sesamoid reduction is a potential risk factor for the recurrence of hallux valgus. The purpose of this study was to radiologically investigate changes in sesamoid position after chevron osteotomy and the open lateral soft tissue procedure. METHODS: Sixty-eight feet that underwent operative correction for hallux valgus deformity were reviewed consecutively. The hallux valgus angle (HVA), first to second intermetatarsal angle (IMA), tibial sesamoid position (TSP), distance of the fibular sesamoid (DFS), and translation of the metatarsal head (TMH) were evaluated preoperatively and at final follow-up. RESULTS: While most parameters were significantly decreased after surgery, no significant change in DFS (correction - 1.45 mm, p = 0.08) was noted. The difference between preoperative and postoperative TSP values (ΔTSP) has a moderately positive correlation with difference in TMH values (ΔTMH) (Rho 0.475, p = .000). Other parameters were similarly correlated. CONCLUSIONS: First, metatarsal bone realignment reduced the sesamoid, but its position, relative to the second metatarsal axis (DFS), was unchanged. The sesamoid is reduced by the lateral translation of the first metatarsal but not by medial sesamoid migration.

Inter and intra-observer reliability in assessment of the position of the lateral sesamoid in determining the severity of hallux valgus.

BACKGROUND: The position of the lateral sesamoid on standard dorso-plantar weight bearing radiographs, with respect to the lateral cortex of the first metatarsal, has been shown to correlate well with the degree of the hallux valgus angle. This study aimed to assess the inter- and intra-observer error of this new classification system. METHODS: Five orthopaedic consultants and five trainee orthopaedic surgeons were recruited to assess and document the degree of displacement of the lateral sesamoid on 144 weight-bearing dorso-plantar radiographs on two separate occasions. The severity of hallux valgus was defined as normal (0%), mild (≤50%), moderate (51-≤99%) or severe (≥100%) depending on the percentage displacement of the lateral sesamoid body from the lateral cortical border of the first metatarsal. RESULTS: Consultant intra-observer variability showed good agreement between repeated assessment of the radiographs (mean Kappa=0.75). Intra-observer variability for trainee orthopaedic surgeons also showed good agreement with a mean Kappa=0.73. Intraclass correlations for consultants and trainee surgeons was also high. CONCLUSION: The new classification system of assessing the severity of hallux valgus shows high inter- and intra-observer variability with good agreement and reproducibility between surgeons of consultant and trainee grades.

Lateral sesamoid position in hallux valgus: correlation with the conventional radiological assessment.

BACKGROUND: We aimed to quantify the severity of the hallux valgus based on the lateral sesamoid position and to establish a correlation of our simple assessment method with the conventional radiological assessments. METHODS: We reviewed one hundred and twenty two dorso-plantar weight bearing radiographs of feet. The intermetatarsal and hallux valgus angles were measured by the conventional methods; and the position of lateral sesamoid in relation to first metatarsal neck was assessed by our new and simple method. RESULTS: Significant correlation was noted between intermetatarsal angle and lateral sesamoid position (Rho 0.74, p < 0.0001); lateral sesamoid position and hallux valgus angle (Rho 0.56, p < 0.0001). Similar trends were noted in different grades of severity of hallux valgus in all the three methods of assessment. CONCLUSIONS: Our method of assessing hallux valgus deformity based on the lateral sesamoid position is simple, less time consuming and has statistically significant correlation with that of the established conventional radiological measurements.

Radiographic changes in Thoroughbred yearlings. Part 2: Associations with racing performance.

REASONS FOR PERFORMING STUDY: Although the radiographic examination of yearlings has become commonplace at some large Thoroughbred sales, there are few data to support the decisions facing veterinarians who are asked to evaluate future racing potential. OBJECTIVES: To identify radiographic changes in the fetlocks, proximal sesamoid bones, carpi, tarsi, stifles and fore feet of Thoroughbred yearlings associated with future racing performance during ages 2 and 3 years. METHODS: Radiographs from routine pre- and post sale examinations of 1162 yearlings were used to identify individual radiographic changes in sale yearlings. Starting a race, the percent of starts placed, money earned and earnings per start were used to assess racing performanceand examined for associations with the radiographic changes observed. RESULTS: Overall 946 (81%) yearlings started at least one race during ages 2 or 3 years. Fourteen of 24 (58%) yearlings with moderate or extreme palmar supracondylar lysis of the third metacarpus, 8 of 14 (57%) of those with enthesophyte formation on the proximal sesamoid bones and 19 of 30 (63%) of those with dorsal medial intercarpal joint disease started a race. The odds of starting a race when age 2 or 3 years were 3 times lower for yearlings with these changes (P < 0.01) compared with yearlings that did not have these changes. Twenty-five of 36 (69%) yearlings with proximal dorsal fragmentation of the first phalanx in the hind fetlock started a race and these yearlings were also less likely (OR = 0.51, P = 0.07) to start a race. Yearlings with enthesophyte formation on hind proximal sesamoid bones placed in a smaller percentage of starts (16%, P = 0.01) earned less money (987 US dollars, P = 0.02) and had lower earnings per start (252 US dollars, P = 0.03) compared to starters without this change. CONCLUSIONS: Although many of the changes observed on radiographs of sale yearlings do not appear to influence future racing performance, some are associated with reduced performance. POTENTIAL RELEVANCE: The results of this study are best applied in parallel with the clinical impressions of veterinarians experienced in examining radiographs of sale yearlings. Some findings support those established in the literature as incidental findings and others suggest new areas for concern not previously reported as a problem in Thoroughbred sale yearlings.

Prospective, randomized comparison of proximal crescentic and proximal chevron osteotomies for correction of hallux valgus deformity.

In this study, intermetatarsal angle (IMA) correction, functional outcome, and healing time for the proximal crescentic and proximal chevron osteotomies in moderate to severe hallux valgus deformity were prospectively compared. Seventy-five patients (97 feet) were prospectively randomized to either a proximal crescentic or proximal chevron osteotomy for the correction of moderate to severe hallux valgus deformity with associated metatarsus primus varus. Criteria for study entry included age (adult patients), IMA greater than or equal to 13 degrees, persistent symptoms despite nonoperative treatment, and minimum follow-up of 12 months. Twenty-nine patients (41 feet) in the crescentic group and 37 patients (43 feet) in the chevron group returned for follow-up at an average of 24 and 20 months, respectively. Good results were achieved with both procedures. No statistically significant differences were found with respect to correction of the IMA or to functional outcome between the two groups. Results held true irrespective of patient age, severity of disease, or bilateral involvement. A statistically significant shorter healing time of the first metatarsal was found after proximal chevron osteotomy. Other potential benefits of the chevron procedure included avoidance of dorsiflexion of the first metatarsal, tendency toward less shortening of the first metatarsal, and more medial distribution of tibial sesamoids following surgery, all of which may reduce the potential for development or persistence of transfer lesions.

Assessment of puberty growth spurt in boys and girls--a dental radiographic method.

The first radiographic appearance of adductor sesamoid bone of thumb is considered reliable and is the most commonly used indicator of puberty growth spurt. The purpose of this study was to find out whether the tooth mineralization stage/stages were as reliable an indicator of puberty growth spurt as the adductor sesamoid bone. Puberty assessment has its necessary application in diagnosis, treatment planning of various malocclusions and in medico legal cases. The results indicated that a close relationship existed between tooth mineralization Stage G and appearance of the sesamoid bone. Hence it can be used in dentistry as an indicator for onset of puberty growth spurt via periapical or panoramic radiographs. The result of this study were not applicable to boys as the apical closure of these teeth had already occurred at the time of early radiographic appearance of the adductor sesamoid bone.

Bone scintigraphy in the assessment of the hallucal sesamoids.

Bone scintigraphy is frequently used to evaluate suspected hallucal sesamoid pathology. Increased scintigraphic activity of the hallucal sesamoid is assumed to corroborate clinical suspicion of pathology, but the incidence of such increased uptake has not been studied in an asymptomatic population. Using a 0 to 2 bone scintigraphic rating system, 25 of 86 (29%) asymptomatic infantry recruits and 7 of 27 (26%) asymptomatic sedentary adults were found to have grade 1 or grade 2 activity. When using scintigraphy to evaluate hallucal sesamoid pathology, caution should be used in interpreting the meaning of increased scintigraphic activity.