Distal articular set angle. Etiology and x-ray evaluation

The Reliability of Common Radiographic Measurements Used to Describe Foot Deformities

Radiographic measurements are frequently used to classify deformity and determine treatment options. Correlation coefficients can be used to determine inter- and intrarater reliability. Reliability is a required feature of any measurement if the measurement is to provide valid information. We calculated correlation coefficients for standard radiographic measurements used to categorize foot deformities: this was done for 52 sets of radiographs assessed by 5 raters. We aimed for generalizability, and kept rater instructions to match what was originally published for each measurement of interest with schematic illustration. Overall, our results mostly showed a lack of inter-rater reliability (correlation coefficients <0.4), and strong intrarater reliability (correlation coefficients >0.6), for 12 forefoot and 12 rearfoot radiographic measurements that are commonly used. The results of this investigation bring into question the routine use of radiographic measurements to categorize deformity, select treatments, and measure surgical outcomes, between surgeons, because the validity of these measurements appears to be threatened by weak inter-rater reliability. In order for these measurements to be considered useful, it may be necessary for surgeons to more rigorously define and practice making standard radiographic measurements.

Revisiting the original Akin technique: A comparative analysis of radiographic outcome

BACKGROUND

The Akin osteotomy is widely used to correct the hallux valgus and different fixation techniques have been proposed. Currently most of these procedures coexist, with disagreement on which offers the best results. The aim of this study is to compare the radiological outcome of the original Akin's technique with one in which a staple was used to stabilize the osteotomy. We also assessed whether other factors unrelated to the osteosynthesis could influence the radiological outcome.

METHODS

We retrospectively reviewed data from 118 patients who underwent a scarf and Akin osteotomy. In 60 patients the Akin osteotomy was fixed with a staple and in 58 cases no staple was used. Hallux valgus angle (HVA), distal articular set angle (DASA), interphalangeal angle (IPA) and tibial sesamoid position were measured. The presence of lateral cortex disruption of the phalanx was also included in the analysis.

RESULTS

Six variables significantly influenced the radiological results of the Akin osteotomy: preoperative HVA, IPA and tibial sesamoid position, laterality, postoperative cortical disruption and use of a staple.

CONCLUSION

Ours results suggest that the original Akin's technique seems to offer equal or better results than a variation in which a staple is added to stabilize the osteotomy.

LEVEL OF EVIDENCE

This is a level III retrospective case-control study.

Intrasubject Radiographic Progression of Hallux Valgus Deformity in Patients With and Without Metatarsus Adductus: Bilateral Asymmetric Hallux Valgus Deformity

This study was to analyze intrasubject radiographic progression of the hallux valgus deformity by comparing the mildly and severely affected sides in patients with bilateral asymmetric hallux valgus in the whole group as well as the metatarsus adductus and the nonmetatarsus adductus subgroups. A total of 186 patients with bilateral asymmetrical hallux valgus deformity with a difference of 5° or greater in the hallux valgus angle were included, and 11 radiographic measurements were analyzed. The radiographic differences between the mildly and severely affected sides were compared. Correlation between the changes in the hallux valgus angle and those in other measurements was analyzed, and multiple regression analyses were performed. The anteroposterior talo-second metatarsal angle showed no significant difference between the mildly and severely affected sides. Changes in the intermetatarsal angle and sesamoid rotation angle were significantly associated with the progression of hallux valgus angle in the whole group as well as the nonmetatarsus adductus subgroup. Change in the intermetatarsal angle (p = .006) was the significant factor associated with the progression of hallux valgus angle in the metatarsus adductus subgroup. The anteroposterior talo-second metatarsal angle might be useful in evaluating the overall foot shape in the hallux valgus deformity. Progression of the hallux valgus deformity might be pathophysiologically different between those with and without metatarsus adductus.

Hallux valgus interphalangeus: reliability of radiological assessment

BACKGROUND

Reliable radiographic measurement of hallux valgus interphalangeus (HVI) deformity has a role in guiding surgical management. HVI can be assessed using: The aim of the study is to investigate the reliability of these radiological parameters.

METHODS

Seventy foot radiographs in patients pre and post hallux valgus corrective surgery were assessed by 3 observers. HVI was assessed using the radiological measurements described above. Two-way random, single measure intra-class correlation coefficients were calculated to assess agreement.

RESULTS

Inter-observer reliability showed good agreement for DASA [ICC=0.77(0.61-0.88)], and excellent for HIA [ICC=0.92(0.85-0.96)] and PDPA [ICC=0.91(0.84-0.96)]. Intra-observer reliability was excellent for all angles; DASA [ICC=0.88 (0.76-0.95)], HIA [ICC=0.94(0.86-0.97)] and PDPA [ICC=0.83(0.65-0.92)].

CONCLUSIONS

Reliability is good to excellent among these three radiological techniques for assessing HVI. The HIA and PDPA are slightly more reliable.

The change of first metatarsal head articular surface position after Lapidus arthrodesis

BACKGROUND

The Lapidus procedure has been used for hallux valgus deformity correction since 1931. In some cases, the arthrodesis results in an unfavourable lateral inclination of first metatarsal head articular surface. The objective of our study was to evaluate the change of orientation of this articular surface in relation to the second metatarsal axis by comparing pre- and postoperative radiographs. The secondary target was to evaluate possible benefits of combination of Lapidus and Akin procedures in the reduction of hallux valgus deformity.

METHODS

We evaluated 449 pre- and postoperative radiographs of 134 operations from 2010 to 2015. Routinely used angle measurements were performed on all X-rays. A sum of tangential angle to the second axis and distal articular set angle values was chosen as the best indicator for the deformity correction success.

RESULTS

The mean value of these angles total was 5.2° ±9.3° before and 14.2° ±7.8° after the operation. In the group of patients, where the additional Akin osteotomy was used, the mean value was 5.3° ±8.4° before and 6.9° ±10.2° after the surgery. The mean difference in values between the two groups (with and without Akin procedure) was 7.3° of extra correction in favour of the group with the Akin osteotomy.

CONCLUSIONS

The mean worsening of the tangential angle after Lapidus operation was 6.1° ±6.9°, which counts for significant deterioration after a surgery. The Akin osteotomy was found to be a valuable addition to the Lapidus arthrodesis, which improves the position of articular surfaces in first metatarsophalangeal joint.

Comparison of radiographic and anatomic distal metatarsal articular angle in cadaver feet

BACKGROUND

A few studies report correlations between radiographic and anatomic measurements of the distal metatarsal articular angle (DMAA). However, little is known about how the DMAA correlates with the hallux valgus angle (HVA) and with anatomic and clinical radiographic measurements.

METHODS

We dissected, measured, and radiographed 39 cadaveric feet for evidence of hallux valgus and the DMAA. We then correlated these values with paired clinical radiographic measurements made by physician evaluators.

RESULTS

Physician measurement of DMAA and anatomic measurement of DMAA were significantly correlated with a mean r = 0.64 (evaluator range, 0.44-0.66). Pairwise correlation between physician evaluators ranged from r = 0.63 to 0.84. Sixty-six percent of physician-measured DMAAs were within 5 degrees of anatomic DMAA.

CONCLUSION

The percentage of radiographic DMAAs that were within 5 degrees of anatomic DMAAs was only 66%. Additionally, the DMAA was increased in the specimens with moderate and severe hallux valgus compared with those with normal or mild hallux valgus angles.

CLINICAL RELEVANCE

The DMAA is an important consideration in patients with hallux valgus. While it is less reliable than other radiographic measures, it was correlated to deformity severity in specimen with hallux valgus.

Reliability and relationship of radiographic measurements in hallux valgus

BACKGROUND

Although various radiographic measurements have been developed and used for evaluating hallux valgus, not all are universally believed to be necessary and their relationships have not been clearly established. Determining which are related could provide some insight into which might be useful and which would not.

QUESTIONS/PURPOSES

We investigated the reliability of eight radiographic measurements used to evaluate hallux valgus, and determined which were correlated and which predicted the hallux valgus angle.

METHODS

We determined eight radiographic indices for 732 patients (mean age, 51 years; SD, 17 years; 107 males and 625 females) with hallux valgus: hallux valgus angle, intermetatarsal angle, hallux interphalangeal angle, distal metatarsal articular angle, proximal phalangeal articular angle, simplified metatarsus adductus angle, first metatarsal protrusion distance, and sesamoid rotation angle. Intraobserver and interobserver reliabilities of each radiographic measurement were analyzed on 36 feet from 36 randomly selected patients. Correlations among the radiographic measurements were analyzed. Radiographic measurements predicting hallux valgus angle were evaluated using multiple regression analysis.

RESULTS

Hallux valgus angle had the highest reliability, whereas the distal metatarsal articular angle and simplified metatarsus adductus angle had the lowest. Distal metatarsal articular angle, intermetatarsal angle, and sesamoid rotation angle had the highest correlations with hallux valgus angle. Distal metatarsal articular angle correlated with sesamoid rotation angle. The intermetatarsal angle, interphalangeal angle, distal metatarsal articular angle, first metatarsal protrusion distance, sesamoid rotation angle, and metatarsus adductus angle predicted the hallux valgus angle.

CONCLUSIONS

We suggest using hallux valgus angle, intermetatarsal angle, interphalangeal angle, sesamoid rotation angle, and first metatarsal protrusion distance considering their reliability and prediction of the deformity.

First metatarsal bone: an anatomic study

BACKGROUND

The purpose of this study was to establish the range of anatomic variations of the first metatarsal bone, including both the angulations of the articular surfaces and the dimensions of the bone in a large sample.

METHODS

Four hundred and seventy-eight first metatarsal bones of 239 cadaver specimens were studied. The following parameters were recorded: the distal metatarsal articular angle (DMAA), distal metatarsal articular surface shape, proximal metatarsal articular angle (PMAA), the first metatarsal bone length and width at the mid-region of the shaft, and the existence of a joint between the bases of the first and second metatarsals. These parameters were correlated to the specimen's age, sex, race, height, and weight. The DMAA and PMAA were measured from a digital picture of the first metatarsal bone by a specially designed computer analysis program.

RESULTS

Males and African-American race had a longer and wider metatarsal. The joint between the first and second bases was present in 25% of the population. The DMAA ranged from -14 degrees of medial deviation to 30 degrees of lateral deviation with an overall average of 8.21 degrees. The DMAA increased 1 to 3 degrees with every 10 years in age for both right and left bones with a p value of < 0.01 and < 0.001, respectively, and the average increase from 20 to 60 years of age was 4.5 degrees. The PMAA ranged from -13.8 degrees of lateral deviation to 12.7 degrees of medial deviation with an overall average of -1 degrees. PMAA significantly deviated laterally in the presence of a joint between the bases of the first and second metatarsals (p < 0.001). The male and female means for the DMAA and PMAA were nearly equal.

CONCLUSIONS

The DMAA had a wider range than reported in the literature, and it increased with age. The first-second metatarsal joint was accompanied by lateral deviation of the PMAA.

CLINICAL RELEVANCE

Laterally deviated PMAA could predispose to a varus deformity of the first metatarsal.

The oblique proximal phalangeal osteotomy in the correction of hallux valgus

An oblique proximal phalangeal osteotomy is introduced as an alternative to the Akin procedure for the treatment of hallux valgus. It consists of a single oblique osteotomy directed from proximal-dorsal to plantar-distal. A retrospective review of 32 patients who underwent 36 oblique proximal osteotomies is presented. The mean follow-up was 11 months (range, 3 to 21 months). Pre- and postoperative radiographic measurements of the distal articular set angles showed an average correction angle of 12 degrees (range, 7 degrees to 22 degrees; SD = 2.99). Mean range of first metatarsophalangeal joint motion was 82% of the preoperative value when combined with distal metatarsal osteotomy, and 87% of the preoperative value without a distal metatarsal osteotomy. Time to clinical and radiographic healing averaged 5 weeks (range, 4 to 8 weeks). The average amount of phalangeal shortening was 1 mm (range, 0 to 2 mm). There were no delayed or nonunions. Subjective assessment conducted by retrospective review of 19 patients at 6 months postoperatively showed that 17 were completely satisfied (90%), 1 was satisfied (5%), and 1 fairly satisfied (5%). Nineteen would have the surgery again (1 with reservations). Eighteen were very satisfied with appearance and 1 was improved. Fourteen returned to shoe gear at weeks 6 to 8, and 5 returned at weeks 8 to 12. Eighteen were satisfied with pain relief and 1 was improved. The study indicates that the oblique proximal phalangeal osteotomy is an effective, reliable, and technically simple procedure for correction of deformities of the proximal phalanx. The advantages include minimal shortening, ease of adjustability, and a construct conducive to rigid fixation.

Intra- and inter-observer reliability of the distal metatarsal articular angle in adult hallux valgus

There is some uncertainty as to whether the distal metatarsal articular angle (DMAA) is a real entity or just radiographic artifact and whether it can be reliably measured. If it is intrinsic to the bone, it should not change with bone position. If it is clinically useful, it should be reproducible. Pre-operative and post-operative radiographs of 32 patients undergoing a proximal bony procedure of the first ray were evaluated independently by three foot and ankle specialists in order to determine the intra and inter-observer reliability of the distal metatarsal articular angle (DMAA). In addition, the hallux valgus angle (HVA), intermetatarsal angle (IMA) and joint congruency/subluxation were determined. We used ANOVA (Scheffe's F-test) to determine reliability of the angular measurements; a p value of less than 0.05 indicates poor reliability and a p value of greater than 0.05 indicates reliability. Intra-observer reliability was good for all angular measurements (HVA, IMA, DMAA pre-op, and DMAA post-op) with p values ranging from 0.33 to 0.95. Inter-observer reliability of the HVA and IMA was good (p=0.63 and p=0.32). Inter-observer reliability of the pre-op DMAA approached statistically poor reliability (p=0.09) and the post-op DMAA reliability was poor (p=0.002). The DMAA reduced after the proximal procedure as measured by all observers, and averaged a reduction of 3.9 degrees. Weighted kappa analysis also revealed that there was poor agreement in the determination of congruency and subluxation (Kappa statistic ranged from 0.07 to 0.19). This study suggests that there may be limited value in the DMAA as a clinical measure as it varies with examiner and with the hallux valgus angle.

First metatarsal head-shaft angle: a method of determination

The distal metatarsal angle (DMAA) is a measurement of the relationship between the longitudinal axis of the first metatarsal and the articular surface of the metatarsal head. We measured the DMAA on radiographs with and without markers on the articular edges and compared them with measurements of the anatomic specimens. Based on the studies, the significance of the radiographic measurements to the actual DMAA and the normal distribution of the measurement were determined.