Total hip arthroplasty is a widely utilized surgical treatment option for osteoarthritis of the hip, with good long-term outcomes25,26,16,17,18,19,20,21,23. However, few outcomes have been reported for patients undergoing THA with a lack of, or minimal, preoperative radiographic disease burden23,24,25,26,27,28,29. Our study is one of the largest databases of patients undergoing THA with minimal disease burden to our knowledge. Therefore, we aimed to define and analyze patient outcomes and compare these patients to those with significant radiographic disease. Our data suggests that patients with hip disease, irrespective of the severity of radiographic grading, can still improve after total hip arthroplasty.
This study has limitations. First, this retrospective study represents a single surgeon’s experience with an emphasis on hip preservation surgery in a high-volume practice. This author (JW) is a technical expert, and as a single-surgeon series, this is a strength and weakness. The results obtained might not accurately reflect the experiences of low-volume practices, thus limiting the generalizability. Future research should consider utilizing larger sample sizes to enhance the applicability of our findings. This would greatly bolster the generalizability of our results, especially for high-volume joint centers where this study could serve as a valuable reference for guiding surgeons. Moreover, it's important to note that our study did not assess or correct intraoperative head and neck offset, nor did it analyze postoperative radiographs for head and neck offset during the initial surgical timeframe. Existing literature has demonstrated the significance of femoroacetabular impingement (FAI) following total hip arthroplasty (THA), which can significantly impact patient outcomes30. Unfortunately, we could not stratify our data to account for FAI-related impairments in this study.
The relatively short follow-up period for joint arthroplasty should be considered, as longer follow-up periods provide a more comprehensive understanding of the intervention's effects over time. Our study had a mean follow-up time of 680 days, and we do not know if long-term follow-up timeframes will have similar patient outcomes between each group. Addressing these limitations through prospective designs, longer follow-up periods, and larger sample sizes would strengthen the validity of our findings and open avenues for further exploration. Another consideration for future research would be classifying outcomes based on a more sensitive imaging modality, such as magnetic resonance imaging (MRI).
HHS and HOS have historically been the gold standard for quantifying patient outcomes following THA16,17,18,19,20,21. HHS domains covered are pain, function, absence of deformity, and range of motion, with scores ≥ 80 denoted as clinically accurate criteria for determining good patient outcomes16,19. HOS contains two domains, activities of daily living (ADL) and sports, that consist of 28 items21. There is no particular HOS score designating a good outcome; however, higher HOS scores represent a higher level of physical function for both the ADL and sports subscales21. We have shown that despite not having significant preoperative radiographic disease with preserved joint space, patients have improved HHS and HOS scores following THA. In addition, patients with less severe baseline radiographic findings had similar HHS and higher HOS metrics post-operatively when compared to those with more severe radiographic findings.
Our results include a higher number of hips (83) undergoing primary THA without or with mild preoperative radiographic osteoarthritis (Tönnis Grade of 0–1) and directly contradict the findings when compared to the existing literature. Dowsey et al. reported on 382 primary THAs with varying levels of radiographic OA severity (modified Kellgren-Lawrence, mK-L) on the minimum difference (MID, as designated by half the standard deviation of the mean change) in pain and function scores at 1 and 2 years compared to baseline. Their results showed that odds ratios for THAs demonstrating a MID in pain and function scores with less severe baseline radiographic changes were significantly lower at 1 and 2 years than those with severe radiographic changes30. However, this study is limited by only having 4 patients with a mK-L severity of less than 3 (moderate osteoarthritis). Similarly, Tilbury et al. reported on 302 primary THAs, comparing hip disability and osteoarthritis outcome scores (HOOS) in patients with mild OA (n = 78) versus severe OA (n = 224) (Kellgren-Lawrence (KL) scores 0–2 vs. 3–4)34. Results were notable for lower degrees of change in HOOS for patients with mild OA; however, comparisons were not made on post-operative HOOS scores between the two groups, which is the aim of our study34. Additionally, Valdes et al. examined 928 post-THA patients and stated individuals with lower radiographic severity (n = 72) were more likely to experience higher pain postoperatively at a mean of 3.2 years35. Although we did not collect WOMAC pain data in this study, our data contradicts these findings when comparing HHS pain subscales between groups.