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Osteochondral Lesions in Surgically Treated Hallux Valgus James R. Jastifer, Michael J. Coughlin, Jesse F. Doty, Faustin R. Stevens, Christopher Hirose and Travis J. Kemp Foot Ankle Int 2014 35: 643 originally published online 7 April 2014 DOI: 10.1177/1071100714531234 The online version of this article can be found at: http://fai.sagepub.com/content/35/7/643
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research-article2014
FAIXXX10.1177/1071100714531234Foot & Ankle InternationalJastifer et al
Article
Osteochondral Lesions in Surgically Treated Hallux Valgus
Foot & Ankle International® 2014, Vol. 35(7) 643–649 © The Author(s) 2014 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1071100714531234 fai.sagepub.com
James R. Jastifer, MD1, Michael J. Coughlin, MD1, Jesse F. Doty, MD2, Faustin R. Stevens, MD3, Christopher Hirose, MD1, and Travis J. Kemp, MD4
Abstract Background: Patient dissatisfaction following surgical correction of hallux valgus remains a clinical problem. The aim of this study was to investigate articular erosion patterns of the first metatarsal head in patients with hallux valgus, to evaluate if the cartilage damage was associated with the degree of hallux valgus deformity, and to prospectively evaluate the effect on patient outcomes. Methods: Fifty-six consecutive feet undergoing surgical correction for hallux valgus were prospectively enrolled and followed for 24 months postoperatively. In addition to clinical and radiographic examinations, intraoperative measurements were obtained to quantify osteochondral lesion location, size, and grade of the first metatarsal head cartilage. Results: Fifty-one of 56 feet (91%) had osteochondral lesions. The mean number of zones affected was 2.9, and the mean maximum International Cartilage Repair Society (ICRS) scale lesion grade was 2.9 out of 4. A total of 44/56 (79%) completed a minimum of 24 months of follow-up. The grade of the lesion and the extent of the lesion did not have a strong correlation with the radiographic measures or clinical outcome scores. Conclusions: This study showed a high prevalence of osteochondral lesions in patients undergoing operative correction of hallux valgus. Since the grade and the extent of the lesions did not have a strong correlation with the severity of the deformity or the clinical outcome, the significance of these lesions remains unknown. Level of Evidence: Level III, comparative series. Keywords: hallux valgus, osteochondritis dissecans, bunion First metatarsal head and sesamoid cartilaginous lesions have been shown to be associated with hallux valgus deformities.1,7,9,13,15 The evaluation of these lesions should be considered in the treatment of the deformity. The American Orthopaedic Foot and Ankle Society has recommended that the evaluation of articular damage of the first metatarsophalangeal joint be included in the standard clinical data evaluation for a hallux valgus deformity.14 While several studies document the incidence of cartilage lesions in patients with hallux valgus in both cadavers and at the time of surgical correction, none to the authors’ knowledge correlate cartilage lesions to patient symptoms or outcomes.9,13 The aim of this study was to investigate articular erosion patterns of the first metatarsal head, including size, grade, and location of the cartilage lesions, to evaluate if the cartilage damage was associated with the degree of a hallux valgus deformity, and to prospectively evaluate the effect that these variables may have on patient outcomes. Our hypothesis was that lesion grade and surface area would correlate with radiographic measures of deformity and patient clinical outcomes.
Methods Institutional review board approval was obtained, and a 24-month prospective cohort study was performed.
Inclusion Criteria Inclusion criteria were patients with pain isolated to the region of the first metatarsophalangeal joint associated with a hallux valgus deformity that was refractory to shoe modifications, nonsteroidal anti-inflammatory medications, or modification of activities who underwent operative correction of 1
Saint Alphonsus Coughlin Foot & Ankle Clinic, Boise, ID, USA UT-Erlanger Foot and Ankle Institute, Chattanooga, TN, USA 3 Tri-City Orthopaedics, Kennewick, WA, USA 4 Allied Orthopaedics, Boise, ID, USA 2
Corresponding Author: James R. Jastifer, MD, Saint Alphonsus Coughlin Foot & Ankle Clinic, 1075 N Curtis Rd, Ste 300, Boise, ID 83706, USA. Email: [email protected]
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their hallux valgus deformity. Exclusion criteria included rheumatoid arthritis or other inflammatory arthropathy, traumatic origin of the hallux deformity, previous forefoot surgery on the ipsilateral foot, history of diabetes mellitus, history of peripheral neuropathy, or those with peripheral neuropathy on examination. The initial preoperative evaluation included patient demographics, a visual analog pain (VAS) scale score, subjective numbness, the American Orthopaedic Foot and Ankle Society (AOFAS) Hallux Metatarsophalangeal Joint Scale score,8 physical examination, and radiographs. The hallux valgus angle (HVA), the 1-2 intermetatarsal angle (IMA), and the hallux interphalangeal joint angle (HVIP) were measured and recorded using mid-diaphyseal reference points.5 The distal metatarsal articular angle (DMAA) was also recorded to evaluate the relationship between the articular surface of the distal first metatarsal and the diaphysis of the first metatarsal.12 Radiographic evidence of first metatarsophalangeal degenerative joint disease was graded as described by Coughlin and Shurnas.6 All angles were measured with a commercial computerized digital templating software package Orthoview™ (version 6.0.14, Jacksonville, Florida). The preoperative clinical and radiographic examination was repeated at 3, 6, and 24 months postoperatively. At the time of surgery, the first metatarsal head was directly examined for evidence of chondral lesions through a standard “L” shaped medial capsulotomy with dorsal and proximal limbs. The chondral lesions were graded according to the International Cartilage Repair Society scale:3 grade 0 = normal; grade 1 = nearly normal, superficial fissures; grade 2 = lesions less than 50% cartilage depth; grade 3 = lesions greater than 50% cartilage depth or down to subchondral bone; grade 4 = lesions through subchondral bone. The lesion surface area was calculated by using the lesion height and width, and measured using a handheld digital caliper (catalog #721 A-6/150, L.S. Starrett Co, Athol, MA) with a measuring error of .04 mm. The lesions were then categorized according to location based on schematics described by Roukis et al and subsequently found to be reliable by others.13,15 This classification system divides the first metatarsal head into 9 zones. Zones 1 to 6 are located anteriorly on the first metatarsal head. Zones 7 to 9 are located plantarly on the first metatarsal head (Figure 1). The first metatarsal head was evaluated, and lesion prevalence, surface area, and grade were recorded independently for each zone. Individual zones were combined to create select zone groupings for lesion prevalence, surface area, and maximum grade. The select zone groupings were anterior metatarsal head (zones 1-6), superior anterior metatarsal head (zones 1-3), inferior anterior metatarsal head (zones 4-6), medial anterior metatarsal head (zones 1, 4), central anterior metatarsal head (zones 2, 5), lateral anterior metatarsal head (zones 3, 6), and plantar metatarsal head (zones 7-9).
Figure 1. First metatarsal head zones.
Linear relationships between cartilage lesion endpoints, clinical, and radiographic data were estimated by Pearson’s correlation coefficient where r ranges from 0 to 1. An r of 0 means no correlation, .5 is a fair correlation, .8 and above is a good correlation, 1 is a perfect positive correlation. Mean comparisons between groups were made with a Student t test. Statistical tests were performed at a .05 level of significance. A post hoc power analysis was performed, which indicated that a group of 44 patients would provide 90% power to detect a Pearson’s r correlation coefficient of .47 or greater. All statistical analysis was performed with R version 2.11.1 software (http://cran.r-project.org/).
Results Intraoperative Osteochondral Lesions A total of 56 feet underwent intraoperative evaluation. Fiftyone of 56 (91%) had lesions on examination. The mean total
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Jastifer et al Table 1. Mean Number of Zones Affected and Maximum Lesion Grade by Severity of Hallux Valgus. Hallux valgus angle
Number of specimens evaluated
Number of specimens with lesion
Percentage with lesion
Mean number of zones affected
Mean maximum lesion grade
3 8 23 22
2 7 23 19
67 88 100 86
1.7 3.3 3.1 2.7
3.0 3.4 2.9 2.6
30
Table 2. Estimated Pearson’s Correlation Coefficient (r) Between Maximum Lesion Grade in All Zones and Hallux Valgus (HV) Angle, Intermetatarsal (IM) Angle, Hallux Interphalangeal (HI) Angle, and Distal Metatarsal Articular (DMA) Angle. HV angle r –.28
1-2 IM angle
HI angle
DMA angle
P
r
P
r
P
r
P
.04
–.21
.14
–.08
.56
–.13
.35
Table 3. Estimated Pearson’s Correlation Coefficient (r) Between Number of Zones With Lesion and Hallux Valgus (HV) Angle, 1-2 Intermetatarsal (1-2 IM) Angle, Hallux Interphalangeal (HI) Angle, and Distal Metatarsal Articular (DMA) Angle. HV angle r .05
1-2 IM angle
HI angle
DMA angle
P
r
P
r
P
r
P
.73
.06
.64
–.07
.60
.06
.68
lesion surface area was 50 mm2 among the 51 patients. Fifteen patients had 2 lesions and 3 had 3 separate lesions. In all, 7% (4/56) had a maximum of grade 1 lesions, 18% (10/56) had a maximum of grade 2 lesions, 50% (28/56) had a maximum of grade 3 lesions, and 16% (9/56) had a maximum of grade 4 lesions. The mean maximum lesion grade was 3.0 for a HVA of less than 15 degrees, 3.4 for a HVA of 15 to 20 degrees, 2.9 for a HVA of 21 to 30 degrees, and 2.6 for a HVA greater than 30 degrees (Table 1). The overall maximum lesion grade had a negative and weak correlation with the HVA (r = –.28, P = .04), but there was no correlation with the DMAA (r = –.13, P = .35), the 1-2 IMA (r = –.21, P = .14), or the HVIP angle (r = –.08, P = .56) (Table 2). We believe the correlation with HVA, while statistically significant, is likely not clinically significant. Maximum lesion grade did not correlate significantly with age (r = .23, P = .10), and mean maximum lesion grade did not differ significantly by gender (male mean = 2.5, female mean = 2.9, P = .21). The mean number of zones eroded for all patients was 2.9 zones. The mean number of zones eroded was 1.7 zones for a HVA of less than 15 degrees, 3.3 zones for a HVA of 15 to 20 degrees, 3.1 zones for a HVA 21 to 30 degrees, and 2.7 zones for a HVA greater than 30 degrees (Table 1). No significant correlation was seen between the number of zones with lesions and HVA, 1-2 IMA, HI angle, or DMAA
(Table 3). The number of zones eroded did not correlate significantly with age (r = .19, P = .15), and the mean number of zones eroded did not differ significantly by gender (male mean = 2.9, female mean = 3.2, P = .71). The erosion rate of the anterior metatarsal head (zones 1-6) was 80%. For the superior anterior metatarsal head (zones 1-3), the erosion rate was 38%. The erosion rate of the interior anterior metatarsal head (zones 4-6) was 80%. Thus no patient had a lesion only in zones 1 to 3. The erosion rate of the plantar metatarsal head (zones 7-9) was 77%. In general, the lesions tended to be central and medial in location. When comparing the inferior portion to the superior portion of the anterior metatarsal head, each respective inferior zone was more commonly affected than its superior counterpart. The rate of medial anterior metatarsal head erosion (zones 1 and 4) was 25% compared to the lateral anterior metatarsal head (zones 3 and 6), which was 16%. The rate of anterior metatarsal head zone erosion from greatest to least was as follows: central inferior 77% (zone 5), central superior 30% (zone 2), medial inferior 25% (zone 4), medial superior 16% (zone 1), lateral inferior 13% (zone 6), and lateral superior 7% (zone 3) (Table 4). The mean total lesion surface area per specimen including all zones was 30 mm2 for a HVA less than 15 degrees, 44 mm2 for a HVA of 15 to 20 degrees, 54 mm2 for a HVA of 21 to 30 degrees, and 40 mm2 for a HVA of greater than 30 degrees. The mean total lesion surface area isolated to the metatarsophalangeal compartment (zones 1-6) was 18 mm2 for a HVA less than 15 degrees, 28 mm2 for a HVA of 15 to 20 degrees, 27 mm2 for a HVA of 21 to 30 degrees, and 18 mm2 for a HVA greater than 30 degrees (Table 5). The lesion area in all zones correlated poorly with the HVA (r = .03, P = .84), the DMAA (r = –.07, P = .62), the 1-2 IMA (r = –.05, P = .55), and the HI angle (r = –.05, P = .73). Lesion area was also broken down by zone, with no clinically significant correlation noted (Table 6). Lesion area in all zones was positively correlated with age (r = .28, P = .04), but mean lesion area in all zones did not differ significantly by gender (male mean = 53, female mean = 45, P = .63).
Clinical Outcomes A total of 44/56 (79%) went on to complete 24 months of follow-up and were included in the clinical data analysis. A
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Table 4. Erosion Rate by Zone. Zone
Erosion rate (%)
1 2 3 4 5 6 7 8 9 Medial anterior metatarsal (1 and/or 4) Central anterior metatarsal (2 and/or 5) Lateral anterior metatarsal (3 and/or 6) Superior anterior metatarsal (1-3) Inferior anterior metatarsal (4-6) Anterior metatarsal head (1-6) Plantar metatarsal head (7-9)
16 30 7 25 77 13 34 71 16 25 77 16 38 80 80 77
Table 5. Lesion Surface Area (mm2) by Increasing Severity of the Hallux Valgus Angle. Mean lesion surface area Hallux Metatarsophalangeal Metatarsosesamoid First metatarsal valgus angle joint (zones 1-6) joint (zones 7-9) head (zones 1-9) 30
18 28 27 18
13 16 26 22
30 44 54 40
total of 91% (40/44) of these patients had a cartilage lesion. There were 5 males and 39 females in the included population. Mean age was 51 (range, 19-69; SD 15.1) years. Of the 44 feet that were included 23 (52%) were left feet and 21 (48%) were right feet. Family history of hallux valgus was positive in 32/44 (73%). In all, 89% (39/44) underwent a proximal crescentic osteotomy and distal soft tissue procedure, 70% (31/44) underwent an Akin osteotomy, 2% (1/44) underwent a triple osteotomy, and 11% (5/44) underwent a chevron osteotomy. All patients, as a result of 1 of the procedures, underwent a medial incision at the level of the first MTP joint. In all, 77% (34/44) had a symptom duration greater than 2 years and 23% (10/44) less than 2 years. The mean AOFAS forefoot scores improved from 59 points (range, 34-75; SD 9.1) preoperatively to 89 points (range, 64-100; SD 9.8) at 24-month follow-up. The mean HVA improved from 29.1 degrees preoperatively to 9.4 degrees at 24-month follow-up. One patient had recurrent deformity and went on to a first MTP fusion. The mean 1-2 IMA improved from 14.1 degrees to 5.7 degrees. The mean preoperative VAS scores were 5.5 (range, 0-10; SD 2.3), which improved to a mean of 1.2 (range, 0-7; SD 1.9) The
mean AOFAS forefoot scores improved from 58.9 points (range, 34-75; SD 9.1) preoperatively to 88.6 points (range, 64-100, SD 9.8) postoperatively. Total lesion area was not significantly correlated to preoperative or postoperative VAS scores or preoperative or postoperative AOFAS scores. Of the patients who had a preoperative HVA of less than 21 degrees, 100% (8/8) had a good or excellent outcome. Of those with an HVA of 21 degrees or greater, 83% (30/36) had a good or excellent outcome. The relationship between lesion surface area and change in AOFAS score, VAS score, and ability to walk from preoperatively to 24-month followup was examined with the Pearson’s correlation coefficient. No clinically significant relationship existed in the data with the numbers available (Table 7). The mean lesion surface area of the 6 patients who rated their outcome as fair or poor was 67mm2 compared to the other 38 patients who rated their outcome as good or excellent whose mean lesion surface area was 42mm2; this difference was not statistically significant with the numbers available (P = .16). The grade of arthritis on preoperative radiographs was weakly correlated with total lesion area (r = .34, P = .02), but was not significantly correlated with maximum lesion grade (r = .10, P = .53) or number of zones eroded (r = .11, P = .23).
Discussion This study showed that 91% of patients undergoing operative correction of hallux valgus had cartilage lesions of the metatarsophalangeal joint. While these lesions may play a multifactorial role in dissatisfaction after hallux valgus surgery, we were unable to demonstrate a clinically significant correlation among the lesions, patient outcomes, and radiographic measures. The current study supports the concept that severity of the deformity is not strongly correlated with the size or grade of the lesion or the patient outcome at 24 months of follow-up. It is possible that the reason that grade and extent of the lesions did not have a strong correlation with these variables is the high prevalence of these lesions in this patient population. The clinical significance of these lesions is unclear, but the prevalence is high, which is consistent with previously published studies. Assessment of first metatarsophalangeal joint articular damage with regard to a hallux valgus deformity is an important clinical parameter for consideration and has been recommended to be part of standard clinical data collection.14 The assessment and surgical treatment of hallux valgus has been described in detail, but there are few reports regarding the condition of the articular cartilage in hallux valgus deformities.1,13,15 Even less has been documented with regard to the location, size, and severity of chondral damage, with none to the authors knowledge examining patient outcomes. Although osteoarthritis is considered a contraindication to joint preserving surgery,4,10 no report describes the extent of
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Jastifer et al Table 6. Estimated Pearson’s Correlation Coefficient (r) Between Lesion Area and Hallux Valgus (HV) Angle, 1-2 Intermetatarsal (IM) Angle, Hallux Interphalangeal (HI) Angle, and Distal Metatarsal Articular (DMA) Angle. HV angle Zone All zones Zones 1-6 (AMH) Zones 1-3 (superiorly) Zones 4-6 (inferiorly) Zones 1, 4 (medially) Zones 2, 5 (centrally) Zones 3, 6 (laterally) Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 Zones 7-9 (PMH) Zone 7 Zone 8 Zone 9
IM angle
HI angle
DMA angle
r
P
r
P
r
P
r
P
.03 –.05 –.17 .01 .04 –.11 .12 .11 –.27 –.12 .00 –.04 .24 .09 .05 .06 .12
.84 .70 .21 .96 .75 .42 .39 .40 .04 .38 1.00 .79 .07 .50 .69 .66 .36
–.08 –.05 –.07 –.03 –.08 –.03 .12 –.01 –.09 .02 –.11 –.01 .14 –.09 –.10 –.10 .13
.55 .72 .63 .82 .57 .80 .37 .93 .51 .90 .42 .95 .30 .52 .47 .48 .36
–.05 –.01 –.08 .02 .08 –.06 .02 .01 –.09 –.05 .11 –.04 .07 –.07 –.06 –.03 –.10
.73 .96 .58 .86 .57 .66 .87 .96 .51 .72 .41 .78 .62 .62 .68 .82 .46
–.07 .04 –.03 .06 .04 .03 –.02 .08 –.10 .03 .02 .07 –.05 –.15 –.04 –.16 –.05
.62 .77 .85 .65 .75 .85 .86 .57 .44 .84 .88 .63 .70 .29 .79 .23 .70
AMH, anterior metatarsal head; PMH, plantar metatarsal head.
chondral damage acceptable to proceed with operative correction of a hallux valgus deformity. The grid layout of the cartilage defects in the current study allows mapping of the lesion patterns in addition to lesion size and grade. Interestingly, when looking at the anterior metatarsal head, each respective inferior zone was more commonly affected than its superior counterpart. This is seen in the rate of inferior erosion (zones 4-6) of 80% and the rate of superior erosion (zones 1-3) of 38%. These are consistent with Doty et al,7 and we feel this may be due to distal migration of the sesamoids during toe-off as they track inconsistently in their respective grooves with deformity progression. Further studies may elucidate this phenomenon. Analyzing incidence of lesions on the grid in the medial to lateral plane, 77% of patients had involvement of the central AMH (zones 2 and 5), 25% of the medial AMH (zones 1 and 4), and 16% of the lateral AMH (zones 3 and 6). A possible mechanism for this pattern of erosion may be the deviated position of the phalanx with increased pressure from the medial rim of the phalangeal base on the metatarsal head. As the toe is axially loaded in a position of valgus, the medial base of the proximal phalanx articulates with the central portion of the metatarsal head. This erosion pattern may also contribute to the “sagittal groove” and the cartilage medial to the groove undergoing disuse atrophy and erosion.11,13 Roukis et al, in the study first describing the technique for mapping the cartilage of the first MTP joint, examined articular lesions at the time of hallux valgus correction and
reported a 100% occurrence rate of articular lesions in patients over 50 years of age in an average of 5.1 zones.13 The rate in those less than 50 years of age was not reported, but they reported a linear relationship between age and increased incidence of erosion implying a lower rate for younger patients without reporting correlation statistics or statistical methods. Unfortunately they did not report correlation coefficients for relationships between angular measurements and lesion size or grade. Their results led them to suggest that realignment at a younger age, or prior to significant deformity progression, may reduce the likelihood of articular erosion. Our results do not support this notion. Smith et al15 subsequently performed a reliability study of the cartilage mapping, reported on 30 feet operatively treated for hallux valgus deformity and found that the medial portion of the anterior metatarsal head was affected most often with zone 1 and zone 4 affected 87% and 93% of the time, respectively. And while it is unclear why they found such a high prevalence of lesions in zones 1 and 4 compared to the current study values, they did find the current study methods to be reliable. Doty et al showed in their cadaver study that 90% (35 of 39) of extremities had evidence of cartilaginous erosion with a mean of 4.2 zones affected. They did show a statistically significant correlation between both the DMAA and HVA and maximum lesion grade (r = .56 and r = .35, respectively) but not between 1-2 IMA and lesion grade. Although the angular correlations are statistically significant, and the correlations in the current study are not, the
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Table 7. Estimated Pearson’s Correlation Coefficient (r) Between Lesion Area and Change in Outcomes Between Baseline and 24 Months: Change in AOFAS Total Pain Score, Change in Average Pain Score, and Change in Ability to Walk Score, Based on 44 Specimens With Preoperative and 24-Month Measurements. Change in AOFAS total pain score Zone All zones Zones 1-6 (AMH) Zones 1-3 (superiorly) Zones 4-6 (inferiorly) Zones 1, 4 (medially) Zones 2, 5 (centrally) Zones 3, 6 (laterally) Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 Zones 7-9 (PMH) Zone 7 Zone 8 Zone 9
Change in average pain score
Change in ability to walk score
r
P
r
P
r
P
–.02 –.05 .12 –.10 .20 –.20 .03 .22 –.03 –.06 .17 –.22 .06 .01 .10 –.07 .03
.90 .77 .43 .50 .20 .20 .86 .14 .86 .68 .28 .15 .70 .96 .50 .66 .83
.07 .20 –.01 .25 –.20 .34 .21 –.25 .24 .06 –.16 .32 .21 –.05 –.18 .08 –.14
.64 .20 .95 .11 .19 .03 .18 .10 .12 .68 .30 .03 .18 .73 .24 .59 .37
.17 .18 .46 .05 .37 –.03 –.01 .44 .24 .08 .30 –.09 –.04 .11 .13 .07 .01
.27 .23 .00 .76 .01 .86 .97 .00 .12 .62 .05 .54 .80 .48 .39 .66 .96
AMH, anterior metatarsal head; PMH, plantar metatarsal head.
1-2 IMA was not statistically significant and the DMAA and HVA correlations are not strong correlations and may not be clinically significant. Also, the mean number of zones affected of 4.2 zones is more than the 2.9 zones in the current study. This may be accounted for by the fact that theirs was a cadaver study with a mean specimen age of 79 years versus the current study mean of 51 years. Mean lesion grades however are similar in the current study to those reported by Doty et al.7 Breslauer and Cohen showed that articular erosion occurred across the entire range of 1-2 IMAs in their patient population; in fact they found that the majority of the eroded sesamoid cristae were not associated with an increase in the 1-2 IMA.2 This is supported by the current findings of no correlation between lesion and the 1-2 IMAs. Bock et al related the extent of cartilage lesions of the first MTP joint to hallux valgus deformity.1 In 265 feet that were examined, a total of 73.2% had cartilage lesions in a patient population of similar mean age to the current study; 15.5% had grade 1 lesions, 30.9% had a maximum of grade 2 lesions, 19.3% had a maximum of grade 3 lesions, and 7.5% had a maximum of grade 4 lesion. In the current study, the prevalence of lesions was greater, as was the severity of the cartilage lesions, with 7% of patients with a maximum of grade 1 lesions, 18% had a maximum of grade 2 lesions, 50% had a maximum of grade 3 lesions, and 16% had a maximum of grade 4 lesions. The Doty et al study also
noted a higher incidence of lesions than Bock et al, however the population in Doty et al’s study was older. Lui et al performed arthroscopy at the time of hallux valgus correction in 121 patients and found a statistically significant correlation between HVA and prevalence of MTP joint cartilage lesions.9 They did not grade or quantify the lesions, which limits the conclusions in relation of the current study. Taken together, the published studies on osteochondral lesions in hallux valgus are clear that the prevalence of lesions is high in this patient population. Also, the geometric distribution of these lesions seems to be consistent. The cartilage lesions seem to be inferior in location compared to the lesions seen in hallux rigidus, which is generally thought to be a dorsal disease. What is not clear, however, is how the severity of the deformity and clinical outcomes relate to the lesions and the deformity. The high prevalence of the lesions, even in young patients with small deformities, makes correlations difficult to reconcile. The prevalence of these lesions in the normal population remains unknown. It could be the case that the correlations are statistically significant but weak and that the current study was underpowered to detect them. Or, possibly there is no correlation and there is another underlying cause to these lesions that has not been studied. Regardless, the clinically significant point is that the prevalence of osteochondral lesions in hallux valgus is high and could be considered as a component of
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Jastifer et al patient dissatisfaction, which is likely multifactorial. Patients should be counseled about the prevalence of these lesions when discussing expectations from surgery. This study has several limitations. First, the sample size and follow-up were limited. Even though we obtained consent prior to participation, we had a loss of follow-up between the 6-month and 2-year time periods, which highlights the difficulty of long-term, prospective study of hallux valgus patients. The prospective design with a minimum of 2-year follow-up is a strength of the article as well. Second, there is difficulty and potential for error in the process of obtaining 2-dimensional area measurements from a 3-dimensional cartilage surface. Straight lines become arcs, and much like for a geographic map, the area of the surface of a sphere is inaccurate when translated into a 2-dimensional area. In light of this, we believe the current methods are the best method available and a reliable technique as described by Smith et al.15
Conclusion This study showed that 91% of patients undergoing operative correction of hallux valgus had cartilage lesions of the metatarsophalangeal joint. These lesions did not correlate to postoperative outcomes or preoperative deformity. The significance of these osteochondral lesions is unclear. To put the lesion significance in context, further studies are warranted regarding the prevalence of cartilage lesions in the normal population. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
References 1. Bock P, Kristen KH, Kroner A, Engel A. Hallux valgus and cartilage degeneration in the first metatarsophalangeal joint. J Bone Joint Surg Br. 2004;86:669-673.
2. Breslauer C, Cohen M. Effect of proximal articular set anglecorrecting osteotomies on the hallucal sesamoid apparatus: a cadaveric and radiographic investigation. J Foot Ankle Surg. 2001;40:366-373. 3. Brittberg M, Aglietti P, Gambardella R, et al. ICRS Cartilage Evaluation Package. Wetzikon, Switzerland: International Cartilage Repair Society; 2000. 4. Coughlin MJ. Hallux valgus. J Bone Joint Surg Am. 1996;78:932-966. 5. Coughlin MJ, Saltzman CL, Nunley JA II. Angular measurements in the evaluation of hallux valgus deformities: a report of the ad hoc committee of the American Orthopaedic Foot & Ankle Society on angular measurements. Foot Ankle Int. 2002;23:68-74. 6. Coughlin MJ, Shurnas PS. Hallux rigidus. Grading and longterm results of operative treatment. J Bone Joint Surg Am. 2003;85-A:2072-2088. 7. Doty JF, Coughlin MJ, Schutt S, et al. Articular chondral damage of the first metatarsal head and sesamoids: analysis of cadaver hallux valgus. Foot Ankle Int. 2013;34:1090-1096. doi:10.1177/1071100713481461. 8. Kitaoka HB, Alexander IJ, Adelaar RS, et al. Clinical rating systems for the ankle-hindfoot, midfoot, hallux, and lesser toes. Foot Ankle Int. 1994;15:349-353. 9. Lui TH. First metatarsophalangeal joint arthroscopy in patients with hallux valgus. Arthroscopy. 2008;24:11221129. doi:10.1016/j.arthro.2008.05.006. 10. Mann RA. Decision-making in bunion surgery. Instr Course Lect. 1990;39:3-13. 11. Miller F, Arenson D, Weil LS. Incongruity of the first metatarsophalangeal joint. The effect on cartilage contact surface area. J Am Podiatry Assoc. 1977;67:328-333. 12. Richardson EG, Graves SC, McClure JT, Boone RT. First metatarsal head-shaft angle: a method of determination. Foot Ankle. 1993;14:181-185. 13. Roukis TS, Weil LS, Landsman AS. Predicting articular erosion in hallux valgus: clinical, radiographic, and intraoperative analysis. J Foot Ankle Surg. 2005;44:13-21. doi:S1067251604005885 [pii] 10.1053/j.jfas.2004.11.012. 14. Smith RW, Reynolds JC, Stewart MJ. Hallux valgus assessment: report of research committee of American Orthopaedic Foot and Ankle Society. Foot Ankle. 1984;5:92-103. 15. Smith SE, Landorf KB, Gilheany MF, Menz HB. Development and reliability of an intraoperative first metatarsophalangeal joint cartilage evaluation tool for use in hallux valgus surgery. J Foot Ankle Surg. 2011;50:31-36. doi:S10672516(10)00404-7 [pii] 10.1053/j.jfas.2010.10.004.
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Osteochondral Lesions in Surgically Treated Hallux Valgus James R. Jastifer, Michael J. Coughlin, Jesse F. Doty, Faustin R. Stevens, Christopher Hirose and Travis J. Kemp Foot Ankle Int 2014 35: 643 originally published online 7 April 2014 DOI: 10.1177/1071100714531234 The online version of this article can be found at: http://fai.sagepub.com/content/35/7/643
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research-article2014
FAIXXX10.1177/1071100714531234Foot & Ankle InternationalJastifer et al
Article
Osteochondral Lesions in Surgically Treated Hallux Valgus
Foot & Ankle International® 2014, Vol. 35(7) 643–649 © The Author(s) 2014 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1071100714531234 fai.sagepub.com
James R. Jastifer, MD1, Michael J. Coughlin, MD1, Jesse F. Doty, MD2, Faustin R. Stevens, MD3, Christopher Hirose, MD1, and Travis J. Kemp, MD4
Abstract Background: Patient dissatisfaction following surgical correction of hallux valgus remains a clinical problem. The aim of this study was to investigate articular erosion patterns of the first metatarsal head in patients with hallux valgus, to evaluate if the cartilage damage was associated with the degree of hallux valgus deformity, and to prospectively evaluate the effect on patient outcomes. Methods: Fifty-six consecutive feet undergoing surgical correction for hallux valgus were prospectively enrolled and followed for 24 months postoperatively. In addition to clinical and radiographic examinations, intraoperative measurements were obtained to quantify osteochondral lesion location, size, and grade of the first metatarsal head cartilage. Results: Fifty-one of 56 feet (91%) had osteochondral lesions. The mean number of zones affected was 2.9, and the mean maximum International Cartilage Repair Society (ICRS) scale lesion grade was 2.9 out of 4. A total of 44/56 (79%) completed a minimum of 24 months of follow-up. The grade of the lesion and the extent of the lesion did not have a strong correlation with the radiographic measures or clinical outcome scores. Conclusions: This study showed a high prevalence of osteochondral lesions in patients undergoing operative correction of hallux valgus. Since the grade and the extent of the lesions did not have a strong correlation with the severity of the deformity or the clinical outcome, the significance of these lesions remains unknown. Level of Evidence: Level III, comparative series. Keywords: hallux valgus, osteochondritis dissecans, bunion First metatarsal head and sesamoid cartilaginous lesions have been shown to be associated with hallux valgus deformities.1,7,9,13,15 The evaluation of these lesions should be considered in the treatment of the deformity. The American Orthopaedic Foot and Ankle Society has recommended that the evaluation of articular damage of the first metatarsophalangeal joint be included in the standard clinical data evaluation for a hallux valgus deformity.14 While several studies document the incidence of cartilage lesions in patients with hallux valgus in both cadavers and at the time of surgical correction, none to the authors’ knowledge correlate cartilage lesions to patient symptoms or outcomes.9,13 The aim of this study was to investigate articular erosion patterns of the first metatarsal head, including size, grade, and location of the cartilage lesions, to evaluate if the cartilage damage was associated with the degree of a hallux valgus deformity, and to prospectively evaluate the effect that these variables may have on patient outcomes. Our hypothesis was that lesion grade and surface area would correlate with radiographic measures of deformity and patient clinical outcomes.
Methods Institutional review board approval was obtained, and a 24-month prospective cohort study was performed.
Inclusion Criteria Inclusion criteria were patients with pain isolated to the region of the first metatarsophalangeal joint associated with a hallux valgus deformity that was refractory to shoe modifications, nonsteroidal anti-inflammatory medications, or modification of activities who underwent operative correction of 1
Saint Alphonsus Coughlin Foot & Ankle Clinic, Boise, ID, USA UT-Erlanger Foot and Ankle Institute, Chattanooga, TN, USA 3 Tri-City Orthopaedics, Kennewick, WA, USA 4 Allied Orthopaedics, Boise, ID, USA 2
Corresponding Author: James R. Jastifer, MD, Saint Alphonsus Coughlin Foot & Ankle Clinic, 1075 N Curtis Rd, Ste 300, Boise, ID 83706, USA. Email: [email protected]
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their hallux valgus deformity. Exclusion criteria included rheumatoid arthritis or other inflammatory arthropathy, traumatic origin of the hallux deformity, previous forefoot surgery on the ipsilateral foot, history of diabetes mellitus, history of peripheral neuropathy, or those with peripheral neuropathy on examination. The initial preoperative evaluation included patient demographics, a visual analog pain (VAS) scale score, subjective numbness, the American Orthopaedic Foot and Ankle Society (AOFAS) Hallux Metatarsophalangeal Joint Scale score,8 physical examination, and radiographs. The hallux valgus angle (HVA), the 1-2 intermetatarsal angle (IMA), and the hallux interphalangeal joint angle (HVIP) were measured and recorded using mid-diaphyseal reference points.5 The distal metatarsal articular angle (DMAA) was also recorded to evaluate the relationship between the articular surface of the distal first metatarsal and the diaphysis of the first metatarsal.12 Radiographic evidence of first metatarsophalangeal degenerative joint disease was graded as described by Coughlin and Shurnas.6 All angles were measured with a commercial computerized digital templating software package Orthoview™ (version 6.0.14, Jacksonville, Florida). The preoperative clinical and radiographic examination was repeated at 3, 6, and 24 months postoperatively. At the time of surgery, the first metatarsal head was directly examined for evidence of chondral lesions through a standard “L” shaped medial capsulotomy with dorsal and proximal limbs. The chondral lesions were graded according to the International Cartilage Repair Society scale:3 grade 0 = normal; grade 1 = nearly normal, superficial fissures; grade 2 = lesions less than 50% cartilage depth; grade 3 = lesions greater than 50% cartilage depth or down to subchondral bone; grade 4 = lesions through subchondral bone. The lesion surface area was calculated by using the lesion height and width, and measured using a handheld digital caliper (catalog #721 A-6/150, L.S. Starrett Co, Athol, MA) with a measuring error of .04 mm. The lesions were then categorized according to location based on schematics described by Roukis et al and subsequently found to be reliable by others.13,15 This classification system divides the first metatarsal head into 9 zones. Zones 1 to 6 are located anteriorly on the first metatarsal head. Zones 7 to 9 are located plantarly on the first metatarsal head (Figure 1). The first metatarsal head was evaluated, and lesion prevalence, surface area, and grade were recorded independently for each zone. Individual zones were combined to create select zone groupings for lesion prevalence, surface area, and maximum grade. The select zone groupings were anterior metatarsal head (zones 1-6), superior anterior metatarsal head (zones 1-3), inferior anterior metatarsal head (zones 4-6), medial anterior metatarsal head (zones 1, 4), central anterior metatarsal head (zones 2, 5), lateral anterior metatarsal head (zones 3, 6), and plantar metatarsal head (zones 7-9).
Figure 1. First metatarsal head zones.
Linear relationships between cartilage lesion endpoints, clinical, and radiographic data were estimated by Pearson’s correlation coefficient where r ranges from 0 to 1. An r of 0 means no correlation, .5 is a fair correlation, .8 and above is a good correlation, 1 is a perfect positive correlation. Mean comparisons between groups were made with a Student t test. Statistical tests were performed at a .05 level of significance. A post hoc power analysis was performed, which indicated that a group of 44 patients would provide 90% power to detect a Pearson’s r correlation coefficient of .47 or greater. All statistical analysis was performed with R version 2.11.1 software (http://cran.r-project.org/).
Results Intraoperative Osteochondral Lesions A total of 56 feet underwent intraoperative evaluation. Fiftyone of 56 (91%) had lesions on examination. The mean total
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Jastifer et al Table 1. Mean Number of Zones Affected and Maximum Lesion Grade by Severity of Hallux Valgus. Hallux valgus angle
Number of specimens evaluated
Number of specimens with lesion
Percentage with lesion
Mean number of zones affected
Mean maximum lesion grade
3 8 23 22
2 7 23 19
67 88 100 86
1.7 3.3 3.1 2.7
3.0 3.4 2.9 2.6
30
Table 2. Estimated Pearson’s Correlation Coefficient (r) Between Maximum Lesion Grade in All Zones and Hallux Valgus (HV) Angle, Intermetatarsal (IM) Angle, Hallux Interphalangeal (HI) Angle, and Distal Metatarsal Articular (DMA) Angle. HV angle r –.28
1-2 IM angle
HI angle
DMA angle
P
r
P
r
P
r
P
.04
–.21
.14
–.08
.56
–.13
.35
Table 3. Estimated Pearson’s Correlation Coefficient (r) Between Number of Zones With Lesion and Hallux Valgus (HV) Angle, 1-2 Intermetatarsal (1-2 IM) Angle, Hallux Interphalangeal (HI) Angle, and Distal Metatarsal Articular (DMA) Angle. HV angle r .05
1-2 IM angle
HI angle
DMA angle
P
r
P
r
P
r
P
.73
.06
.64
–.07
.60
.06
.68
lesion surface area was 50 mm2 among the 51 patients. Fifteen patients had 2 lesions and 3 had 3 separate lesions. In all, 7% (4/56) had a maximum of grade 1 lesions, 18% (10/56) had a maximum of grade 2 lesions, 50% (28/56) had a maximum of grade 3 lesions, and 16% (9/56) had a maximum of grade 4 lesions. The mean maximum lesion grade was 3.0 for a HVA of less than 15 degrees, 3.4 for a HVA of 15 to 20 degrees, 2.9 for a HVA of 21 to 30 degrees, and 2.6 for a HVA greater than 30 degrees (Table 1). The overall maximum lesion grade had a negative and weak correlation with the HVA (r = –.28, P = .04), but there was no correlation with the DMAA (r = –.13, P = .35), the 1-2 IMA (r = –.21, P = .14), or the HVIP angle (r = –.08, P = .56) (Table 2). We believe the correlation with HVA, while statistically significant, is likely not clinically significant. Maximum lesion grade did not correlate significantly with age (r = .23, P = .10), and mean maximum lesion grade did not differ significantly by gender (male mean = 2.5, female mean = 2.9, P = .21). The mean number of zones eroded for all patients was 2.9 zones. The mean number of zones eroded was 1.7 zones for a HVA of less than 15 degrees, 3.3 zones for a HVA of 15 to 20 degrees, 3.1 zones for a HVA 21 to 30 degrees, and 2.7 zones for a HVA greater than 30 degrees (Table 1). No significant correlation was seen between the number of zones with lesions and HVA, 1-2 IMA, HI angle, or DMAA
(Table 3). The number of zones eroded did not correlate significantly with age (r = .19, P = .15), and the mean number of zones eroded did not differ significantly by gender (male mean = 2.9, female mean = 3.2, P = .71). The erosion rate of the anterior metatarsal head (zones 1-6) was 80%. For the superior anterior metatarsal head (zones 1-3), the erosion rate was 38%. The erosion rate of the interior anterior metatarsal head (zones 4-6) was 80%. Thus no patient had a lesion only in zones 1 to 3. The erosion rate of the plantar metatarsal head (zones 7-9) was 77%. In general, the lesions tended to be central and medial in location. When comparing the inferior portion to the superior portion of the anterior metatarsal head, each respective inferior zone was more commonly affected than its superior counterpart. The rate of medial anterior metatarsal head erosion (zones 1 and 4) was 25% compared to the lateral anterior metatarsal head (zones 3 and 6), which was 16%. The rate of anterior metatarsal head zone erosion from greatest to least was as follows: central inferior 77% (zone 5), central superior 30% (zone 2), medial inferior 25% (zone 4), medial superior 16% (zone 1), lateral inferior 13% (zone 6), and lateral superior 7% (zone 3) (Table 4). The mean total lesion surface area per specimen including all zones was 30 mm2 for a HVA less than 15 degrees, 44 mm2 for a HVA of 15 to 20 degrees, 54 mm2 for a HVA of 21 to 30 degrees, and 40 mm2 for a HVA of greater than 30 degrees. The mean total lesion surface area isolated to the metatarsophalangeal compartment (zones 1-6) was 18 mm2 for a HVA less than 15 degrees, 28 mm2 for a HVA of 15 to 20 degrees, 27 mm2 for a HVA of 21 to 30 degrees, and 18 mm2 for a HVA greater than 30 degrees (Table 5). The lesion area in all zones correlated poorly with the HVA (r = .03, P = .84), the DMAA (r = –.07, P = .62), the 1-2 IMA (r = –.05, P = .55), and the HI angle (r = –.05, P = .73). Lesion area was also broken down by zone, with no clinically significant correlation noted (Table 6). Lesion area in all zones was positively correlated with age (r = .28, P = .04), but mean lesion area in all zones did not differ significantly by gender (male mean = 53, female mean = 45, P = .63).
Clinical Outcomes A total of 44/56 (79%) went on to complete 24 months of follow-up and were included in the clinical data analysis. A
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Table 4. Erosion Rate by Zone. Zone
Erosion rate (%)
1 2 3 4 5 6 7 8 9 Medial anterior metatarsal (1 and/or 4) Central anterior metatarsal (2 and/or 5) Lateral anterior metatarsal (3 and/or 6) Superior anterior metatarsal (1-3) Inferior anterior metatarsal (4-6) Anterior metatarsal head (1-6) Plantar metatarsal head (7-9)
16 30 7 25 77 13 34 71 16 25 77 16 38 80 80 77
Table 5. Lesion Surface Area (mm2) by Increasing Severity of the Hallux Valgus Angle. Mean lesion surface area Hallux Metatarsophalangeal Metatarsosesamoid First metatarsal valgus angle joint (zones 1-6) joint (zones 7-9) head (zones 1-9) 30
18 28 27 18
13 16 26 22
30 44 54 40
total of 91% (40/44) of these patients had a cartilage lesion. There were 5 males and 39 females in the included population. Mean age was 51 (range, 19-69; SD 15.1) years. Of the 44 feet that were included 23 (52%) were left feet and 21 (48%) were right feet. Family history of hallux valgus was positive in 32/44 (73%). In all, 89% (39/44) underwent a proximal crescentic osteotomy and distal soft tissue procedure, 70% (31/44) underwent an Akin osteotomy, 2% (1/44) underwent a triple osteotomy, and 11% (5/44) underwent a chevron osteotomy. All patients, as a result of 1 of the procedures, underwent a medial incision at the level of the first MTP joint. In all, 77% (34/44) had a symptom duration greater than 2 years and 23% (10/44) less than 2 years. The mean AOFAS forefoot scores improved from 59 points (range, 34-75; SD 9.1) preoperatively to 89 points (range, 64-100; SD 9.8) at 24-month follow-up. The mean HVA improved from 29.1 degrees preoperatively to 9.4 degrees at 24-month follow-up. One patient had recurrent deformity and went on to a first MTP fusion. The mean 1-2 IMA improved from 14.1 degrees to 5.7 degrees. The mean preoperative VAS scores were 5.5 (range, 0-10; SD 2.3), which improved to a mean of 1.2 (range, 0-7; SD 1.9) The
mean AOFAS forefoot scores improved from 58.9 points (range, 34-75; SD 9.1) preoperatively to 88.6 points (range, 64-100, SD 9.8) postoperatively. Total lesion area was not significantly correlated to preoperative or postoperative VAS scores or preoperative or postoperative AOFAS scores. Of the patients who had a preoperative HVA of less than 21 degrees, 100% (8/8) had a good or excellent outcome. Of those with an HVA of 21 degrees or greater, 83% (30/36) had a good or excellent outcome. The relationship between lesion surface area and change in AOFAS score, VAS score, and ability to walk from preoperatively to 24-month followup was examined with the Pearson’s correlation coefficient. No clinically significant relationship existed in the data with the numbers available (Table 7). The mean lesion surface area of the 6 patients who rated their outcome as fair or poor was 67mm2 compared to the other 38 patients who rated their outcome as good or excellent whose mean lesion surface area was 42mm2; this difference was not statistically significant with the numbers available (P = .16). The grade of arthritis on preoperative radiographs was weakly correlated with total lesion area (r = .34, P = .02), but was not significantly correlated with maximum lesion grade (r = .10, P = .53) or number of zones eroded (r = .11, P = .23).
Discussion This study showed that 91% of patients undergoing operative correction of hallux valgus had cartilage lesions of the metatarsophalangeal joint. While these lesions may play a multifactorial role in dissatisfaction after hallux valgus surgery, we were unable to demonstrate a clinically significant correlation among the lesions, patient outcomes, and radiographic measures. The current study supports the concept that severity of the deformity is not strongly correlated with the size or grade of the lesion or the patient outcome at 24 months of follow-up. It is possible that the reason that grade and extent of the lesions did not have a strong correlation with these variables is the high prevalence of these lesions in this patient population. The clinical significance of these lesions is unclear, but the prevalence is high, which is consistent with previously published studies. Assessment of first metatarsophalangeal joint articular damage with regard to a hallux valgus deformity is an important clinical parameter for consideration and has been recommended to be part of standard clinical data collection.14 The assessment and surgical treatment of hallux valgus has been described in detail, but there are few reports regarding the condition of the articular cartilage in hallux valgus deformities.1,13,15 Even less has been documented with regard to the location, size, and severity of chondral damage, with none to the authors knowledge examining patient outcomes. Although osteoarthritis is considered a contraindication to joint preserving surgery,4,10 no report describes the extent of
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Jastifer et al Table 6. Estimated Pearson’s Correlation Coefficient (r) Between Lesion Area and Hallux Valgus (HV) Angle, 1-2 Intermetatarsal (IM) Angle, Hallux Interphalangeal (HI) Angle, and Distal Metatarsal Articular (DMA) Angle. HV angle Zone All zones Zones 1-6 (AMH) Zones 1-3 (superiorly) Zones 4-6 (inferiorly) Zones 1, 4 (medially) Zones 2, 5 (centrally) Zones 3, 6 (laterally) Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 Zones 7-9 (PMH) Zone 7 Zone 8 Zone 9
IM angle
HI angle
DMA angle
r
P
r
P
r
P
r
P
.03 –.05 –.17 .01 .04 –.11 .12 .11 –.27 –.12 .00 –.04 .24 .09 .05 .06 .12
.84 .70 .21 .96 .75 .42 .39 .40 .04 .38 1.00 .79 .07 .50 .69 .66 .36
–.08 –.05 –.07 –.03 –.08 –.03 .12 –.01 –.09 .02 –.11 –.01 .14 –.09 –.10 –.10 .13
.55 .72 .63 .82 .57 .80 .37 .93 .51 .90 .42 .95 .30 .52 .47 .48 .36
–.05 –.01 –.08 .02 .08 –.06 .02 .01 –.09 –.05 .11 –.04 .07 –.07 –.06 –.03 –.10
.73 .96 .58 .86 .57 .66 .87 .96 .51 .72 .41 .78 .62 .62 .68 .82 .46
–.07 .04 –.03 .06 .04 .03 –.02 .08 –.10 .03 .02 .07 –.05 –.15 –.04 –.16 –.05
.62 .77 .85 .65 .75 .85 .86 .57 .44 .84 .88 .63 .70 .29 .79 .23 .70
AMH, anterior metatarsal head; PMH, plantar metatarsal head.
chondral damage acceptable to proceed with operative correction of a hallux valgus deformity. The grid layout of the cartilage defects in the current study allows mapping of the lesion patterns in addition to lesion size and grade. Interestingly, when looking at the anterior metatarsal head, each respective inferior zone was more commonly affected than its superior counterpart. This is seen in the rate of inferior erosion (zones 4-6) of 80% and the rate of superior erosion (zones 1-3) of 38%. These are consistent with Doty et al,7 and we feel this may be due to distal migration of the sesamoids during toe-off as they track inconsistently in their respective grooves with deformity progression. Further studies may elucidate this phenomenon. Analyzing incidence of lesions on the grid in the medial to lateral plane, 77% of patients had involvement of the central AMH (zones 2 and 5), 25% of the medial AMH (zones 1 and 4), and 16% of the lateral AMH (zones 3 and 6). A possible mechanism for this pattern of erosion may be the deviated position of the phalanx with increased pressure from the medial rim of the phalangeal base on the metatarsal head. As the toe is axially loaded in a position of valgus, the medial base of the proximal phalanx articulates with the central portion of the metatarsal head. This erosion pattern may also contribute to the “sagittal groove” and the cartilage medial to the groove undergoing disuse atrophy and erosion.11,13 Roukis et al, in the study first describing the technique for mapping the cartilage of the first MTP joint, examined articular lesions at the time of hallux valgus correction and
reported a 100% occurrence rate of articular lesions in patients over 50 years of age in an average of 5.1 zones.13 The rate in those less than 50 years of age was not reported, but they reported a linear relationship between age and increased incidence of erosion implying a lower rate for younger patients without reporting correlation statistics or statistical methods. Unfortunately they did not report correlation coefficients for relationships between angular measurements and lesion size or grade. Their results led them to suggest that realignment at a younger age, or prior to significant deformity progression, may reduce the likelihood of articular erosion. Our results do not support this notion. Smith et al15 subsequently performed a reliability study of the cartilage mapping, reported on 30 feet operatively treated for hallux valgus deformity and found that the medial portion of the anterior metatarsal head was affected most often with zone 1 and zone 4 affected 87% and 93% of the time, respectively. And while it is unclear why they found such a high prevalence of lesions in zones 1 and 4 compared to the current study values, they did find the current study methods to be reliable. Doty et al showed in their cadaver study that 90% (35 of 39) of extremities had evidence of cartilaginous erosion with a mean of 4.2 zones affected. They did show a statistically significant correlation between both the DMAA and HVA and maximum lesion grade (r = .56 and r = .35, respectively) but not between 1-2 IMA and lesion grade. Although the angular correlations are statistically significant, and the correlations in the current study are not, the
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Table 7. Estimated Pearson’s Correlation Coefficient (r) Between Lesion Area and Change in Outcomes Between Baseline and 24 Months: Change in AOFAS Total Pain Score, Change in Average Pain Score, and Change in Ability to Walk Score, Based on 44 Specimens With Preoperative and 24-Month Measurements. Change in AOFAS total pain score Zone All zones Zones 1-6 (AMH) Zones 1-3 (superiorly) Zones 4-6 (inferiorly) Zones 1, 4 (medially) Zones 2, 5 (centrally) Zones 3, 6 (laterally) Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 Zones 7-9 (PMH) Zone 7 Zone 8 Zone 9
Change in average pain score
Change in ability to walk score
r
P
r
P
r
P
–.02 –.05 .12 –.10 .20 –.20 .03 .22 –.03 –.06 .17 –.22 .06 .01 .10 –.07 .03
.90 .77 .43 .50 .20 .20 .86 .14 .86 .68 .28 .15 .70 .96 .50 .66 .83
.07 .20 –.01 .25 –.20 .34 .21 –.25 .24 .06 –.16 .32 .21 –.05 –.18 .08 –.14
.64 .20 .95 .11 .19 .03 .18 .10 .12 .68 .30 .03 .18 .73 .24 .59 .37
.17 .18 .46 .05 .37 –.03 –.01 .44 .24 .08 .30 –.09 –.04 .11 .13 .07 .01
.27 .23 .00 .76 .01 .86 .97 .00 .12 .62 .05 .54 .80 .48 .39 .66 .96
AMH, anterior metatarsal head; PMH, plantar metatarsal head.
1-2 IMA was not statistically significant and the DMAA and HVA correlations are not strong correlations and may not be clinically significant. Also, the mean number of zones affected of 4.2 zones is more than the 2.9 zones in the current study. This may be accounted for by the fact that theirs was a cadaver study with a mean specimen age of 79 years versus the current study mean of 51 years. Mean lesion grades however are similar in the current study to those reported by Doty et al.7 Breslauer and Cohen showed that articular erosion occurred across the entire range of 1-2 IMAs in their patient population; in fact they found that the majority of the eroded sesamoid cristae were not associated with an increase in the 1-2 IMA.2 This is supported by the current findings of no correlation between lesion and the 1-2 IMAs. Bock et al related the extent of cartilage lesions of the first MTP joint to hallux valgus deformity.1 In 265 feet that were examined, a total of 73.2% had cartilage lesions in a patient population of similar mean age to the current study; 15.5% had grade 1 lesions, 30.9% had a maximum of grade 2 lesions, 19.3% had a maximum of grade 3 lesions, and 7.5% had a maximum of grade 4 lesion. In the current study, the prevalence of lesions was greater, as was the severity of the cartilage lesions, with 7% of patients with a maximum of grade 1 lesions, 18% had a maximum of grade 2 lesions, 50% had a maximum of grade 3 lesions, and 16% had a maximum of grade 4 lesions. The Doty et al study also
noted a higher incidence of lesions than Bock et al, however the population in Doty et al’s study was older. Lui et al performed arthroscopy at the time of hallux valgus correction in 121 patients and found a statistically significant correlation between HVA and prevalence of MTP joint cartilage lesions.9 They did not grade or quantify the lesions, which limits the conclusions in relation of the current study. Taken together, the published studies on osteochondral lesions in hallux valgus are clear that the prevalence of lesions is high in this patient population. Also, the geometric distribution of these lesions seems to be consistent. The cartilage lesions seem to be inferior in location compared to the lesions seen in hallux rigidus, which is generally thought to be a dorsal disease. What is not clear, however, is how the severity of the deformity and clinical outcomes relate to the lesions and the deformity. The high prevalence of the lesions, even in young patients with small deformities, makes correlations difficult to reconcile. The prevalence of these lesions in the normal population remains unknown. It could be the case that the correlations are statistically significant but weak and that the current study was underpowered to detect them. Or, possibly there is no correlation and there is another underlying cause to these lesions that has not been studied. Regardless, the clinically significant point is that the prevalence of osteochondral lesions in hallux valgus is high and could be considered as a component of
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Jastifer et al patient dissatisfaction, which is likely multifactorial. Patients should be counseled about the prevalence of these lesions when discussing expectations from surgery. This study has several limitations. First, the sample size and follow-up were limited. Even though we obtained consent prior to participation, we had a loss of follow-up between the 6-month and 2-year time periods, which highlights the difficulty of long-term, prospective study of hallux valgus patients. The prospective design with a minimum of 2-year follow-up is a strength of the article as well. Second, there is difficulty and potential for error in the process of obtaining 2-dimensional area measurements from a 3-dimensional cartilage surface. Straight lines become arcs, and much like for a geographic map, the area of the surface of a sphere is inaccurate when translated into a 2-dimensional area. In light of this, we believe the current methods are the best method available and a reliable technique as described by Smith et al.15
Conclusion This study showed that 91% of patients undergoing operative correction of hallux valgus had cartilage lesions of the metatarsophalangeal joint. These lesions did not correlate to postoperative outcomes or preoperative deformity. The significance of these osteochondral lesions is unclear. To put the lesion significance in context, further studies are warranted regarding the prevalence of cartilage lesions in the normal population. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
References 1. Bock P, Kristen KH, Kroner A, Engel A. Hallux valgus and cartilage degeneration in the first metatarsophalangeal joint. J Bone Joint Surg Br. 2004;86:669-673.
2. Breslauer C, Cohen M. Effect of proximal articular set anglecorrecting osteotomies on the hallucal sesamoid apparatus: a cadaveric and radiographic investigation. J Foot Ankle Surg. 2001;40:366-373. 3. Brittberg M, Aglietti P, Gambardella R, et al. ICRS Cartilage Evaluation Package. Wetzikon, Switzerland: International Cartilage Repair Society; 2000. 4. Coughlin MJ. Hallux valgus. J Bone Joint Surg Am. 1996;78:932-966. 5. Coughlin MJ, Saltzman CL, Nunley JA II. Angular measurements in the evaluation of hallux valgus deformities: a report of the ad hoc committee of the American Orthopaedic Foot & Ankle Society on angular measurements. Foot Ankle Int. 2002;23:68-74. 6. Coughlin MJ, Shurnas PS. Hallux rigidus. Grading and longterm results of operative treatment. J Bone Joint Surg Am. 2003;85-A:2072-2088. 7. Doty JF, Coughlin MJ, Schutt S, et al. Articular chondral damage of the first metatarsal head and sesamoids: analysis of cadaver hallux valgus. Foot Ankle Int. 2013;34:1090-1096. doi:10.1177/1071100713481461. 8. Kitaoka HB, Alexander IJ, Adelaar RS, et al. Clinical rating systems for the ankle-hindfoot, midfoot, hallux, and lesser toes. Foot Ankle Int. 1994;15:349-353. 9. Lui TH. First metatarsophalangeal joint arthroscopy in patients with hallux valgus. Arthroscopy. 2008;24:11221129. doi:10.1016/j.arthro.2008.05.006. 10. Mann RA. Decision-making in bunion surgery. Instr Course Lect. 1990;39:3-13. 11. Miller F, Arenson D, Weil LS. Incongruity of the first metatarsophalangeal joint. The effect on cartilage contact surface area. J Am Podiatry Assoc. 1977;67:328-333. 12. Richardson EG, Graves SC, McClure JT, Boone RT. First metatarsal head-shaft angle: a method of determination. Foot Ankle. 1993;14:181-185. 13. Roukis TS, Weil LS, Landsman AS. Predicting articular erosion in hallux valgus: clinical, radiographic, and intraoperative analysis. J Foot Ankle Surg. 2005;44:13-21. doi:S1067251604005885 [pii] 10.1053/j.jfas.2004.11.012. 14. Smith RW, Reynolds JC, Stewart MJ. Hallux valgus assessment: report of research committee of American Orthopaedic Foot and Ankle Society. Foot Ankle. 1984;5:92-103. 15. Smith SE, Landorf KB, Gilheany MF, Menz HB. Development and reliability of an intraoperative first metatarsophalangeal joint cartilage evaluation tool for use in hallux valgus surgery. J Foot Ankle Surg. 2011;50:31-36. doi:S10672516(10)00404-7 [pii] 10.1053/j.jfas.2010.10.004.
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