Abstract
Background: The purpose of this investigation is to compare the radiographic and intraoperative assessment of scaphotrapezoid (ST) joint arthritis in patients with end-stage carpometacarpal (CMC) arthritis of the thumb base. We aim to define the incidence of ST arthritis in this population and determine whether radiographic features such as lunate morphology, dorsal intercalated segment instability (DISI), and scapholunate (SL) diastasis are associated with the incidence of ST arthritis. Methods: We retrospectively reviewed consecutive patients with end-stage CMC arthritis of the thumb treated operatively with trapeziectomy. Preoperative wrist radiographs were reviewed, and the presence of ST arthritis was determined using the Sodha classification. Lunate morphology, DISI, and SL diastasis were noted. Intraoperative grading of ST arthritis was assessed using a modified Brown classification. The specificity and sensitivity of radiographic assessment was compared with the gold standard of intraoperative direct visualization. Results: In total, 302 thumbs met inclusion criteria. End-stage ST joint arthritis determined by intraoperative visual inspection was noted in 31% of cases. No radiographic or demographic variables were found to be risk factors for ST arthritis. Plain radiographs were 47% sensitive and 94% specific in their ability to detect end-stage ST joint arthritis. Conclusions: We report a 31% incidence of end-stage ST joint arthritis in surgically treated patients with CMC arthritis based on visual inspection which is lower than previous literature. Wrist radiographs demonstrate a 47% sensitivity and 94% specificity in predicting end-stage ST joint arthritis. It is imperative to directly visualize the ST joint after trapeziectomy, as radiographs demonstrate poor sensitivity.
Keywords: scaphotrapezoid, carpometacarpal arthritis, osteoarthritis, wrist arthritis, trapeziectomy
Introduction
Carpometacarpal (CMC) arthritis of the thumb base is one the most common symptomatic arthritic conditions in the hand.10 While scaphotrapeziotrapezoid (STT) arthritis has a reported incidence of 16%, concomitant CMC arthritis is associated with an increased incidence of STT arthritis.5 During procedures to address CMC arthritis, inspection and appropriate treatment of the scaphotrapezoid (ST) joint after trapeziectomy is necessary to avoid residual symptoms secondary to ST joint degeneration.2,7
The preoperative diagnosis of ST arthritis in patients with concomitant CMC arthritis is difficult due to the low sensitivity of plain radiographs.7 Prior studies analyzing these 2 conditions have demonstrated a 62% incidence of ST arthritis after trapeziectomy; however, these investigations were limited by small sample size and the utilization of a binary scale to grade degenerative changes both radiographically and intraoperatively.7
The purpose of this investigation is to compare the radiographic and intraoperative assessment of ST joint arthritis in patients with end-stage CMC arthritis of the thumb base. In addition to defining the incidence of ST arthritis in surgically treated patients with end-stage CMC arthritis, we aim to determine whether associated radiographic features, such as lunate morphology, the presence of dorsal intercalated segment instability (DISI), and scapholunate (SL) diastasis are associated with an increased incidence of ST arthritis. We hypothesize that plain radiographs will display poor sensitivity and high specificity for ST arthritis in patients with end-stage CMC arthritis.
Materials and Methods
Institutional review board approval was obtained. We retrospectively reviewed a consecutive series of patients 18 years of age and older with end-stage CMC arthritis of the thumb base treated with trapeziectomy from August 1, 2007, to July 30, 2016. These procedures were performed by a single fellowship-trained hand surgeon. Exclusion criteria included patients undergoing revision CMC joint procedures, patients with previous distal radius fracture or deformity, and patients previously treated surgically for STT joint arthritis. The electronic medical records were reviewed for each patient, and baseline demographics were recorded including age, gender, laterality, hand dominance, comorbid medical conditions, and documentation of metacarpophalangeal (MCP) joint hyperextension >20 .
Preoperative anteroposterior, lateral, and oblique radiographs of the involved wrist were reviewed for all included patients. All radiographic measurements and classifications were reviewed. ST joint arthritis was classified utilizing the system created by Sodha et al (Table 1), which was originally proposed for CMC arthritis.6 Recent investigators have also utilized this system to define the radiographic prevalence of STT arthritis, noting its substantial intraobserver and moderate interobserver reliability.5
Table 1.
| Sodha radiographic staging | Brown visual grading system | |
|---|---|---|
| I | No or nearly no arthrosis | Normal cartilage: smooth, shiny, and intact surfaces |
| II | Arthrosis but a finding that the joint was not destroyed | Early cartilage degeneration: surface fibrillation, minor surface pitting |
| III | Joint destroyed | Progressive cartilage degeneration: deep surface pitting, fissures, clefts, surface blistering, exposed bone |
| IV | — | End-stage cartilage degeneration: eburnated bone |
Lunate morphology was recorded using the classification system proposed by Viegas.8 A Type I lunate was defined as having a single distal facet for the capitate, and did not articulate with the hamate.8 A Type II lunate was defined as having 2 distal facets for both the capitate and the hamate.8 The presence of DISI was defined as a SL angle > 70° and capitolunate angle > 20°. Scapholunate diastasis was recorded in mm for each patient.
Intraoperatively, each patient underwent trapeziectomy through a dorsal approach. After trapeziectomy, the ST joint was visually inspected for arthritis and the state of the articular surface was documented. We utilized a modification of the classification proposed by Brown et al, which is presented in Table 1.1 Both Stage III and Stage IV disease in this visual grading system have exposed subchondral bone, and for the purposes of this investigation, we combined these two into a single stage. As suggested by Tomaino et al and in accordance with our clinical practice, all patients with evidence of exposed subchondral bone (Brown Stage III and IV) underwent a partial excision of the proximal trapezoid.7 Utilizing a 3-point intraoperative grading scale allowed for a more effective comparison to the Sodha 3-point radiographic staging system.
Simple descriptive percentages were calculated to establish the incidence of ST arthritis (as measured by Brown and Sodha classifications). Spearman rank correlation, which is an appropriate measure for ordinal categories like these grading systems, was used to measure the strength of the association between the Brown and Sodha classifications. Simple descriptive percentages were used to describe how many patients in each category had potential demographic and radiographic risk factors for ST arthritis. For categorical risk factors (eg, presence or absence of gout), nonparametric Kruskal-Wallis tests were used to rank all the observations with respect to the modified Brown classification and test for significant differences in ranks between cases with and without the potential risk factors. For continuous variables (eg, age, mm SL diastasis), analysis of variance was used to compare the means among the modified Brown classification groups. Sensitivity and specificity were calculated for radiographic assessment of ST arthritis using the intraoperative direct visualization as the gold standard. Statistical analysis was performed using SAS 9.4 software (SAS Institute, Cary, North Carolina) with P values of <.05 considered significant.
Results
In total, 302 cases in 257 patients met inclusion criteria. All patients included in our series had radiographic evidence of end-stage CMC arthritis. Table 2 describes the basic characteristics of included patients. Of the 257 patients, 195 (76%) were female, with a mean age of 62 years. Radiographic end-stage ST joint arthritis (Sodha Grade III) was noted in 57 of 302 cases (19%), and end-stage ST joint arthritis as determined by intraoperative visual inspection (Brown Stage III / IV) was noted in 94 of 302 cases (31%). The association between Sodha and Brown classifications for all cases is shown in Table 3. These two classification systems demonstrated a statistically significant correlation (Spearman ρ = 0.55, P < .0001).
Table 2.
Baseline Demographics and Radiographic Findings for All Patients.
| Patients, n | 257 |
| Female, n (%) | 195 (76) |
| Age, years | |
| Mean (SD) | 62 (10) |
| Range | 25-89 |
| Procedures, n | 302 |
| Laterality, n (%) | |
| Right | 160 (53) |
| Dominant hand involved, n (%) | 162 (54) |
| MCP joint hyperextension >20° | 65 (22) |
| Medical comorbidities, n (%) | |
| Gout | 6 (2) |
| Pseudogout | 7 (2) |
| Sodha stage, n (%) | |
| I | 179 (59) |
| II | 66 (22) |
| III | 57 (19) |
| Brown visual grade (modified), n (%) | |
| I | 202 (67) |
| II | 6 (2) |
| III/IV | 94 (31) |
| Associated radiographic findings | |
| S-L diastasis in mm, mean (SD) | 1.4 (0.7) |
| S-L diastasis 3 mm or greater, n (%) | 15 (5) |
| DISI, n (%) | 11 (4) |
| Lunate morphology | |
| Type I, n (%) | 230 (76) |
| Type II, n (%) | 72 (24) |
| Pseudogout on x-ray, n (%) | 0 (0) |
Note. MCP = metacarpophalangeal; DISI = dorsal intercalated segment instability.
Table 3.
Comparison of Patient’s Radiographic Changes of the Scaphotrapeziotrapezoid With Intraoperative Findings.
| Sodha I (n = 179) | Sodha II (n = 66) | Sodha III (n = 57) | Spearman coefficient | P value | |
|---|---|---|---|---|---|
| Brown | 0.55 | <.0001 | |||
| I | 156 (87%) | 34 (52%) | 12 (21%) | ||
| II | 0 (0%) | 5 (8%) | 1 (2%) | ||
| III | 23 (13%) | 27 (41%) | 44 (77%) |
A comparison of the demographic and radiographic factors across the 3 modified Brown classification stages is shown in Table 4. No variables were statistically significantly associated with the presence of ST arthritis as noted intraoperatively.
Table 4.
Distribution of Potential Risk Factors Across the 3 Brown Grading Categories.
| Brown I (n = 202) | Brown II (n = 6) | Brown III (n = 94) | P value | |
|---|---|---|---|---|
| Gout, n (%) | 5 (2) | 0 (0) | 1 (1) | .40 |
| Pseudogout, n (%) | 5 (2) | 0 (0) | 2 (2) | .82 |
| Age in years, mean (SD) | 61 (10) | 60 (9) | 64 (9) | .14 |
| Females, n (%) | 154 (76) | 6 (100) | 73 (78) | .68 |
| Dominant hand involved, n (%) | 110 (54) | 2 (33) | 50 (53) | .76 |
| Presence of pseudogout on x-ray, n (%) | 0 (0) | 0 (0) | 0 (0) | >.99 |
| DISI, n (%) | 5 (2) | 0 (0) | 6 (6) | .11 |
| Lunate type II, n (%) | 53 (26) | 1 (17) | 18 (19) | .17 |
| SL joint diastasis | ||||
| Diastasis in mm, mean (SD) | 1.35 (0.67) | 1.52 (0.75) | 1.38 (0.76) | .83 |
| Diastasis ≥ 3mm, n (%) | 10 (5) | 0 (0) | 5 (5) | .94 |
| Thumb MCP joint hyperextended, n (%) | 40 (20) | 1 (17) | 24 (26) | .28 |
Note. DISI = dorsal intercalated segment instability; MCP = metacarpophalangeal.
The sensitivity and specificity of plain films for the assessment of ST arthritis are displayed in Table 5. Plain radiographs were 47% sensitive and 94% specific in their ability to detect end-stage ST joint arthritis.
Table 5.
Sensitivity and Specificity for Predicting Modified Brown Classification Based on the Sodha Classification.
| Sensitivity (95% CI) | Specificity (95% CI) | |
|---|---|---|
| Predicting Brown I based on Sodha I | 77% (71%-83%) | 77% (67%-85%) |
| Predicting Brown III based on Sodha III | 47% (36%-57%) | 94% (90%-97%) |
Note. CI = confidence interval.
Discussion
Radiographic ST joint arthritis has been identified in 16% of patients seen for any hand complaint using the Sodha classification and in 38% of patients using a modified Kellgren-Lawrence scale.1,5,7 Previous studies have shown agreement between visual examination and radiographic evaluation ranging from 29% to 67.5%.1,3,4 Tomaino et al reported a 62% (23/37 patients) incidence of ST joint arthritis based on direct intraoperative visualization in patients undergoing trapeziectomy for end-stage CMC arthritis.7 This compared with a 32% (12/37 patients) incidence utilizing plain radiographs in their series.7 In contrast to these findings, we report a 31% incidence of end-stage ST arthritis based on visual inspection in 302 cases of surgically treated end-stage CMC arthritis and a radiographic incidence of 19%. The difference in these findings may be attributable to a smaller sample size in the prior series.
Tomaino et al previously found that the sensitivity and specificity of plain radiographs for detecting end-stage ST joint arthritis was 44% and 86%, respectively.7 We report similar results with a sensitivity and specificity of 47% and 94%, respectively. Plain radiographs were more sensitive (77% vs 47%) with respect to determining the absence of ST arthritis (Brown Stage I) but were less specific (77% vs 94%). Radiographs underestimate the rate of end-stage ST arthritis. In addition, our data indicate that while plain radiographs are a poor screening test to detect the presence of end-stage ST joint arthritis, when end-stage changes are noted radiographically, they do demonstrate high specificity.
Neither patient baseline demographic factors nor radiographic findings, including the presence of DISI, lunate morphology, SL diastasis, were found to be risk factors for the development of ST arthritis. In a review of 210 patients with radiographic wrist arthritis, Watson and Ballet noted that 57% of cases involved the scaphoid, lunate, and radius and 27% involved the STT joint.9 The authors noted that a combined pattern (STT arthritis and scapholunate advanced collapse [SLAC]) occurred in 15%.9 We did not find an association between SLAC changes and ST arthritis, which may be attributed to the relatively low number of cases with degenerative changes related to SL pathology.
Limitations of our study include a lack of specific preoperative stress films specific to the CMC or ST joints. Posteroanterior stress views of the ST joint space can exhibit narrowing in the presence of arthritis. The films we utilized were a standard wrist series with posteroanterior, lateral, and oblique radiographs. In addition, our cases all were completed at a rural academic center with a homogeneous patient population, and our results may not be generalizable across all demographics.
During procedures to address CMC arthritis of the thumb base, inspection and appropriate treatment of the ST joint after trapeziectomy is necessary to avoid residual symptoms secondary to ST joint degeneration. We report a 31% incidence of end-stage ST joint arthritis in surgically treated patients with CMC arthritis based on visual inspection, which is substantially lower than previously reported in the literature. Wrist radiographs demonstrate a 47% sensitivity and 94% specificity in predicting end-stage ST joint arthritis at the time of surgery, further emphasizing the importance of visually inspecting the ST joint after trapeziectomy, as radiographs are a poor screening test.
Footnotes
Ethical Approval: This retrospective study was approved by the Geisinger Health System IRB (reference #2016-0264).
Statement of Human and Animal Rights: This article does not contain any studies with human or animal subjects.
Statement of Informed Consent: Not applicable.
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.
ORCID iD: A Akoon 
https://orcid.org/0000-0002-3526-4001
References
- 1. Brown G, Roh M, Strauch R, et al. Radiography and visual pathology of the osteoarthritic scaphotrapezio-trapezoidal joint, and its relationship to trapeziometacarpal osteoarthritis. J Hand Surg. 2003;28(5):739-743. [DOI] [PubMed] [Google Scholar]
- 2. Garcia-Elias M, Lluch A, Farreres A, et al. Resection of the distal scaphoid for scaphotrapeziotrapezoid osteoarthritis. J Hand Surg. 1999;24(4):448-452. [DOI] [PubMed] [Google Scholar]
- 3. Glickel S, Kornstein A, Eaton R. Long-term follow-up of trapeziometacarpal arthroplasty with coexisting scaphotrapezial disease. J Hand Surg. 1992;17(A):612-620. [DOI] [PubMed] [Google Scholar]
- 4. North E, Eaton R. Degenerative joint disease of the trapezium: a comparative radiographic and anatomic study. J Hand Surg. 1983;8:160-167. [DOI] [PubMed] [Google Scholar]
- 5. Scordino L, Bernstein J, Nakashian M, et al. Radiographic prevalence of scaphotrapeziotrapezoid osteoarthrosis. J Hand Surg. 2014;39:1677-1682. [DOI] [PubMed] [Google Scholar]
- 6. Sodha S, Ring D, Zurakowski D, et al. Prevalence of osteoarthrosis of the trapeziometacarpal joint. J Bone Joint Surg Am. 2005;87(12):2614-2618. [DOI] [PubMed] [Google Scholar]
- 7. Tomaino M, Vogt M, Weiser R. Scaphotrapezoid arthritis: prevalence in thumbs undergoing trapezium excision arthroplasty and efficacy of proximal trapezoid excision. J Hand Surg. 1999;24(6):1220-1224. [DOI] [PubMed] [Google Scholar]
- 8. Viegas S. The lunatohamate articulation of the midcarpal joint. Arthroscopy. 1990;6(1):5-10. [DOI] [PubMed] [Google Scholar]
- 9. Watson HK, Ballet FL. The SLAC Wrist: scapholunate advanced collapse pattern of degenerative arthritis. J Hand Surg. 1984;9:358-365. [DOI] [PubMed] [Google Scholar]
- 10. Zhang Y, Niu J, Kelly-Hayes M, et al. Prevalence of symptomatic hand osteoarthritis and its impact on functional status among the elderly. Am J Epidemiol. 2002;156:1021-1027. [DOI] [PubMed] [Google Scholar]