Hip joint osteoarthritis, a major cause of disabling pain among older adults, and predicted to occur in one of four older adults in the future 1, has long been considered a chronic health condition that deteriorates over time, and one that often requires surgical joint replacement, or a procedure known as total joint arthroplasty surgery. While commonly successful at reducing pain and increasing mobility 2, joint replacement surgery is not without complications such as joint infection, however 3. Indeed, while infection is not a given as a result of this form of surgery, it is cited to occur quite frequently in primary surgery contexts, as well as in cases requiring revision surgery, along with an array of possible undesirable outcomes and impacts 4. Moreover, even if only a small number of cases are likely to incur periprosthetic joint infections 5, given the immense additional social and personal costs and resultant suffering in the instance of a joint infection, substantive efforts to limit or reduce this occurrence and any further need for revision surgery has been advocated for some time. Indeed, while this situation, which is not easy to predict and resolve, remains a high priority issue for surgeons and hospitals, it is possible even more important to address in light of the ongoing COVID-19 pandemic where the patient may be in more severe pain and less healthy before surgery than in pre COVID-19 times 6.

In this regard, vitamin D, said to be a highly important hormone influencing many bodily functions that must be produced by the body in response to sunlight exposure or provided in supplement or food based formats, is cited as being required for fostering normal macrophage activity and inflammatory responses that may correlate with the presence of various modes of infection 789. Vitamin D may also impact on many physiological processes that have a link to osteoarthritis pathology 10, such as bone health 11. A role for vitamin D deficiency in the pathological processes underlying osteoarthritis can also not be ruled out. Thus, study of this possible association has not only been advocated, but appears to warrant attention, given the numbers of arthroplasty surgeries anticipated in the future, and the fact that prospective surgical candidates are commonly and predictably at high risk for vitamin D deficiencies 12 and likely to possibly be excessively impaired post COVID-19 lockdown situations. They may hence be more vulnerable to surgical infections than in pre pandemic times, as well as requiring prolonged rehabilitation periods due to COVID-19 related precautions and hospital administration changes that may excessively limit sunlight exposure.

To assure that those undergoing surgery in the face of the COVID-19 pandemic, do obtain significantly improved health, well-being and desired life quality status, it appears every effort to guard against unwanted postoperative joint infections should be made and is strongly warranted 3456.

In this respect, Morrison et al. 13 indicate that among an accepted array of precautionary practices, efforts to ensure vitamin D levels are not deficient (a term commonly referring to serum vitamin D levels of less than 20 ng/ml), may prove highly efficacious in minimizing the chances of unwanted post-operative joint infections, and their associated longer than desirable hospital stays. Accordingly, the current review reports on what is known about the role of vitamin D in the context of perioperative infections that continue to occur quite often following total joint replacement surgery 8.

The hip joint is examined as the sources of this dysfunction often require joint replacement surgery include hip fracture patients, who are often elderly with possible low vitamin D levels 9, as well as other prevailing health conditions that may correlate with vitamin D deficits such as obesity or frailty even if these are not directly associated with the disease incidence 2. The hip is also clearly a less well studied joint when compared to comparable data on knee joint arthroplasty infections and vitamin D.

Vitamin D is examined because it may yet have the potential to impact other important osteoarthritis correlates that may be associated in their own right with the disease and the patient’s ability to recover from hip joint surgery in a timely way, for example osteoporosis 14, possible fractures, and falls 10 see Box 1. The presence of insufficient vitamin D may also impact cartilage destruction, muscle atrophy, sarcopenic obesity, muscle strength, muscle recovery, and balance15, as well as arthroplasty surgery outcomes 12.

To achieve the overall aims of the current review, and to possibly answer the question of whether vitamin D is clinically relevant in the context of averting or minimizing post-operative hip arthroplasty infection rates, all pertinent articles listed on the PUBMED, Scopus, and Web of Science Consolidated Data Bases that appeared to inform about vitamin D, hip joint osteoarthritis, and post-surgical joint infections at the hip were sought and those of high relevance were examined specifically.

In this regard, topical articles published predominantly, in the last five years albeit not exclusively if an insightful report was relevant to the topic at hand, were examined and downloaded if deemed relevant. The research material reviewed was not restricted to any particular mode of inquiry, and both preclinical, as well as clinical data were considered relevant if they were peer reviewed full length articles published in English, and discussing vitamin D and its possible role in hip osteoarthritis, hip joint arthroplasty surgery infection outcomes. Articles referring solely to knee or other forms of osteoarthritis were excluded, as were non English articles.

After salient articles were scrutinized to examine if they addressed the present topic and questions of interest, those deemed relevant were selected for review, and discussed solely in narrative form as outlined below. In this regard, the term vitamin D was adopted throughout to describe this compound, mindful that diverse modes of vitamin D exist, along with its various properties, classifications, functional attributes, and typologies. The various modes of determining the extent of any prevailing vitamin D serum concentrations and their cutoff points and definitions of deficiency are reported as they appeared in the related literature, mindful that these are not necessarily uniform nor well standardized or accepted. The term COVID-19 is used to describe the novel corona virus that emerged in 2019 in Wuhan, China.

The key terms outlined below, yielded a limited number of publications that covered the time periods January 1, 2016-December 30, 2020 as per Table 1.

Hip joint osteoarthritis is a widespread health condition, of high concern in the realm of efforts to optimize the wellbeing of older adults worldwide 1230. Since treatments to alleviate the pain, inflammation, mechanical derangement, plus the weakening of joint muscles, bone, and cartilage 30 associated with hip osteoarthritis are often ineffective, surgical procedures are commonly advocated. However, as with all forms of surgery, complications such as infection remain among the most serious outcomes of these total hip joint arthroplasty surgeries 5711, and that may lead to pain, debility, bone and sift tissue erosion, and implant loosening 7, as well as death 62 See Figure 1. This review sought to examine whether there is support for examining vitamin D serum levels among older adults undergoing this form of surgery, and offering vitamin D supplementation to mediate infection rates post hip joint arthroplasty in those adults found to be vitamin D deficient or at risk for a deficiency. A case for the utility of this idea was deemed highly necessary to undertake in light of the persistence of the COVID-19 pandemic where a substantive number of older patients may not only have deficient vitamin D levels 37, but worse hip joint disease manifestations prior to surgery than anticipated due to the impact of the COVID-19 lockdowns on pain, joint function, physical function, and physical activity in patients with end-stage hip osteoarthritis 630. In addition, while in hospital they may be at greater risk than in pre pandemic times to infections 55, due to logistical factors, increased susceptibility, and possible care factors due to staff and resource shortages. Hypovitaminosis D, is also associated with increased susceptibility to frailty, falls, inactivity, and fractures 55. As such, this review, which examined almost all available current reports, revealed that a fair proportion of those older adults who require total hip arthroplasty surgery are likely to not only be vitamin D deficient, among exhibiting other debilitating health issues, but a small albeit important subgroup may sustain periprosthetic joint infections that delay healing and may require prolonged hospitalization and further surgery. On the other hand, efforts to attenuate postsurgical hip infection risk via the administration of vitamin D supplements as needed prior to joint arthroplasty surgery may be of high value in mitigating or averting both excess health deterioration and poorer than desired outcomes, as well as acute periprosthetic infections 48, along with the risk of hospitalization and severe COVID-19 4961.

Arguments against this idea however do prevail, and include, but are not limited to the idea that while baseline vitamin D levels do tend to decline post joint arthroplasty surgery, they also tend to return to baseline levels within six weeks as discussed by Binkley et al. 50. As well, Buirs et al. 51 discount vitamin D as having any bearing on the nature of total hip arthroplasty physical outcomes. This conclusion may arguably not apply to all cases, for example, those who sustain joint infections associated to some possible degree with low baseline vitamin D status or marginal status or other factors, such as the presence of one or more comorbid diseases 52, and/or a decline in vitamin D availability, other health issues or the presence of an overall compromised health status due this chronic situation 48. There is also an increasingly older population undergoing this form of surgery, that may at high risk for low vitamin D serum levels

In the meantime, even though neither Da Rocha et al. 30, nor Rhee et al. 53 mentioned vitamin D in their effort to advise osteoarthritis sufferers during this current ongoing COVID-19 pandemic, and this review may not have sourced all available publications, we agree with the conclusions of Wall and de Steiger 12 who argue that among the number of modifiable factors that increase the risk of postoperative complications following arthroplasty, one factor is the presence of a vitamin D deficiency. The degree to which outcomes are manifest post arthroplasty surgery may also depend on how close to desired levels the subject’s vitamin D status has been over time. Although not mentioned as a risk factor for perioperative infection specifically, Kong et al. 57 note that insufficient serum vitamin D concentrations are found to prevail in 40-65% of cases requiring total hip arthroplasty 58. As well, patients who go on to suffer from periprosthetic hip joint infections are found to have lower vitamin D levels than those who present with aseptic implant loosening complaints 59. Older adults who are candidates for hip joint arthroplasty surgery and who exhibit low vitamin D levels prior to surgery may also be expected to be at greater risk for worse postoperative outcomes, as well as infections, due to factors such as an associated functional decline and falls risk 60.

Consequently, while not conclusive, it is apparent that addressing this possible modifiable risk factor, as indicated, among others, not only over the course of helping the patient to manage their health condition more effectively, but especially prior to the implementation of hip joint arthroplasty surgery may yet help to reduce or hopefully eliminate the risk of adverse outcomes, in general, as well as the need for infection related revision surgery that often leads to premature death 4056. In addition, although more study is needed, parallel data show vitamin D is one important modifiable nutritional factor that is often deficient in the elderly, but one where repletion is a possible cost-effective and plausible approach to reducing postoperative infection risk among older adults scheduled to undergo joint arthroplasty surgery 112745 as well as favorably impacting soft tissue healing and recovery, plus gait recovery, and length of hospital stay after surgery 636465. To this end, and in light of projected increases in the incidence of costly periprosthetic infections among the elderly and their disastrous consequences 66, more extensive research to further a better understanding of the implications of vitamin D serum levels in the context of the health outcomes of adults 65 years of age and above who require hip joint replacement surgery 61 should be undertaken in the near future. This idea is clearly of high possible clinical significance in efforts to attain appropriate surgical outcomes 62, especially in the context of COVID-19, as well as the time period beyond that 666768.

The need for hip joint arthroplasty surgery, which is likely to increase exponentially in the future may yet be impacted negatively in the case of a postsurgical infections, also projected to increase in numbers in the future.

Older adults with disabling hip osteoarthritis who are hip arthroplasty surgical candidates are more likely than not to benefit by efforts to uniformly examine and intervene as indicated to maximize their serum vitamin D levels prior to as well as following any arthroplasty surgery in this regard.

At the same time, adults 65 years of age or older who are diagnosed with hip osteoarthritis and who are asked to defer their scheduled joint replacement surgery appointments in response to COVID-19 lockdowns are likely to benefit from a standardized screening and supplementation effort, owing to the observed impact of isolation on vitamin D availability, and the risk posed by any deficiency towards on both COVID-19 risk, enforced hospitalization, plus possible worse than anticipated hip joint osteoarthritis outcomes.

On the other hand, early and timely administration of vitamin D as required by those older adults at risk for any vitamin D deficiency appears equally valuable for potentially averting surgical need, or in delaying this, while offering the best chances of a speedy safe surgical outcome, with less chance of revision, given the many attributes of vitamin D in the realm of joint health maintenance as well as overall health status.