- Top of page
- MATERIALS AND METHODS
- AUTHOR CONTRIBUTIONS
- ROLE OF THE STUDY SPONSOR
Osteoarthritis (OA) is the leading cause of chronic pain and disability among older people in developed countries (1). Several large population-based studies have reported that radiographic OA of the first metatarsophalangeal (MTP) joint of the foot is common (2). The prevalence of the condition increases with age, and radiographic first MTP joint OA is present in approximately 46% of women and 32% of men at age 60 years (3). Characteristic radiographic features include joint space narrowing (JSN), osteophyte (OP) proliferation of the metatarsal head and proximal phalanx, subchondral sclerosis, subchondral cysts, and sesamoid hypertrophy (4, 5).
OA of the first MTP joint has been commonly described as either hallux limitus or hallux rigidus. The term used depends on the magnitude of available joint motion and the severity of joint degeneration (4). Hallux limitus is characterized by restricted sagittal plane motion (primarily dorsiflexion), whereas hallux rigidus displays an absence of joint motion due to end-stage degenerative joint disease and subsequent joint ankylosis (4). Although the terms are often used interchangeably, hallux rigidus has been adopted by the World Health Organization in the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (6).
People with symptomatic first MTP joint OA typically present with localized pain, stiffness, and an enlarged joint (4, 5). Symptoms are commonly exacerbated by activity and alleviated by rest (4, 5). Reduced first MTP joint dorsiflexion inhibits efficient forward transfer of body weight during the propulsive phase of gait and subsequently leads to alterations in normal foot function (4, 7). Treatment interventions for this condition primarily focus on providing symptomatic relief (8). However, few well-designed studies have investigated the efficacy of these interventions (8).
Traditionally, the severity of chronic musculoskeletal conditions has been categorized according to the level of pain experienced. However, this approach may not necessarily provide a comprehensive and accurate assessment of condition severity from the patient's perspective (9). Health-related quality of life (HRQOL) takes into consideration the patient's perspective of the impact that a chronic condition has on their physical, psychological, and social health and well-being. HRQOL has become a standard and widely used measure of the broad impact of chronic musculoskeletal conditions, including OA (10–13).
A number of generic and specific HRQOL questionnaires have subsequently been developed (10). Generic questionnaires assess universal aspects of general health and well-being, whereas specific questionnaires assess aspects of HRQOL that are associated with a specific condition or body region (10, 14). The Short Form 36 (SF-36) questionnaire (15) and Foot Health Status Questionnaire (FHSQ) (16) are examples of commonly used generic and foot-specific HRQOL measures, respectively. Despite increasing recognition of their importance, few studies have used HRQOL measures to investigate the broad impact of first MTP joint OA (17–19). Using the FHSQ, 3 studies have suggested that symptomatic first MTP joint OA is associated with reduced foot-specific HRQOL (17–19). However, none of these studies compared people with symptomatic first MTP joint OA to an asymptomatic control group. Therefore, it is not possible to determine whether a difference in foot-specific HRQOL exists between people with and without this condition. In addition, the association between symptomatic first MTP joint OA and general HRQOL has not been investigated. Consequently, the impact of symptomatic first MTP joint OA on foot-specific and general HRQOL is not clearly understood.
Therefore, the aim of this study was to determine whether there are differences in the foot-specific and general HRQOL of people with and without radiographically confirmed symptomatic first MTP joint OA.
Significance & Innovations
This is the first study to explore the impact of first metatarsophalangeal (MTP) joint osteoarthritis (OA) on foot-specific and general health-related quality of life (HRQOL) using a case–control study design.
People with symptomatic first MTP joint OA display reduced foot-specific and general HRQOL.
Interventions for first MTP joint OA that focus on improving foot-specific and general HRQOL may lead to better patient outcomes.
- Top of page
- MATERIALS AND METHODS
- AUTHOR CONTRIBUTIONS
- ROLE OF THE STUDY SPONSOR
First MTP joint OA is recognized as a condition that commonly causes foot pain (4, 5). However, no studies have comprehensively investigated the broad impact of this condition using HRQOL outcome measures. Therefore, the primary objective of this study was to compare the foot-specific and general HRQOL of people with and without symptomatic first MTP joint OA.
Foot-specific HRQOL was investigated using the FHSQ. All FHSQ domain scores (foot pain, foot function, footwear, and general foot health) were significantly lower in the case group, indicating that symptomatic first MTP joint OA is associated with reduced foot-specific HRQOL. However, the severity of radiographic OA at the first MTP joint was not correlated with any FHSQ domain scores in the case group participants. These findings demonstrate that people with symptomatic first MTP joint OA experience more foot pain, have greater difficulty performing functional weight-bearing activities, find it more difficult to obtain suitable footwear, and perceive their feet to be in a poorer state of health than those without this condition. However, the severity of impairment is not related to the severity of radiographic degeneration at the first MTP joint. Our findings support earlier case series studies suggesting that people with symptomatic first MTP joint OA have suboptimal FHSQ scores (17–19), but provide stronger evidence due to the inclusion of a control group.
We also evaluated the general HRQOL of the participants using the SF-36 questionnaire. Our results showed that the physical functioning domain of the SF-36 was significantly lower in the case group. Similar to our analysis of foot-specific HRQOL, there were no correlations between the severity of radiographic OA at the first MTP joint with SF-36 domain scores in the case group participants. These findings indicate that people with symptomatic first MTP joint OA have greater difficulty performing a broad range of physical tasks and activities than those without this condition, but the severity of impairment is not related to the severity of radiographic degeneration at the first MTP joint. Further, although not statistically significant, there was also a trend showing that participants with symptomatic first MTP joint OA displayed reduced role physical (d = −0.54), vitality (d = −0.42), and social functioning (d = −0.53) SF-36 domain scores. Our study findings are novel, since no previous study has investigated the general HRQOL of people with first MTP joint OA. Previous studies have shown that all SF-36 domain scores are negatively impacted in those with OA occurring at the hip and knee joints, suggesting that first MTP joint OA has a less broad impact on HRQOL (12, 13). Nevertheless, our results do reinforce the notion that chronic musculoskeletal disease such as OA has a multidimensional impact on HRQOL.
This study addressed the limitations of the previous studies in this area (17–19). First, a reliable radiographic classification system was used to determine the presence and severity of first MTP joint OA (22). Second, both the foot-specific and general HRQOL of people with symptomatic first MTP joint OA was compared to that of an age-, sex-, and BMI-matched control group. There were no significant differences between the case and control groups for the level of education and self-reported comorbidities (except for foot OA). Therefore, we can conclude that the significant differences in HRQOL domains between our study groups are unlikely to be due to these commonly recognized confounding factors. Third, the participants were recruited from the community; therefore, the findings are likely to be broadly generalizable to the general population.
The findings of this study must be interpreted in the context of several limitations. First, although the results of this case–control study suggest that symptomatic first MTP joint OA is associated with reduced foot-specific HRQOL as well as the physical functioning aspect of general HRQOL, we cannot confirm that this relationship is causal. Second, our analyses showed that there were statistically significant correlations between each of the FHSQ domain scores with the SF-36 physical functioning domain scores, suggesting that, to some extent, these tools are measuring overlapping constructs. Third, the validity of the FHSQ and SF-36 for measuring the HRQOL of people with first MTP joint OA has not been fully established. Importantly, the clinically important difference in domain scores of the FHSQ and SF-36 for people with first MTP joint OA is not known. Consequently, it is difficult to determine if the magnitude of the effects observed in this study between those with and without first MTP joint OA are clinically meaningful. However, to attempt to assess the magnitude of any differences, we did determine normalized effect sizes (Cohen's d), and these differences were large (−2.24 to −1.10) for all domains of foot-specific HRQOL and the physical functioning domain of general HRQOL. Fourth, the case group was comprised of participants with radiographically confirmed symptomatic first MTP joint OA. However, people with radiographically confirmed first MTP joint OA may be asymptomatic (37, 38). Therefore, the findings only apply to people with radiographically confirmed symptomatic first MTP joint OA.
The findings of this study indicate that symptomatic first MTP joint OA has a much broader impact than localized pain and discomfort. Symptomatic first MTP joint OA is associated with large reductions in all aspects of foot-specific HRQOL and in the physical functioning aspect of general HRQOL. From a clinical and research perspective, the aspects of foot-specific and general HRQOL that were found to be reduced in people with symptomatic first MTP joint OA should be assessed in those presenting with this condition. Further, treatment interventions for first MTP joint OA that focus on improving localized symptoms as well as those aspects of HRQOL that were shown to be significantly reduced in people with symptomatic first MTP joint OA may lead to improved patient outcomes.