Of the potential 109 participants for the study, 89 had completed data fields and were included which represents an 82% completion rate, and an acceptable and comparable sample size for the study. The demographic profile of the study group is consistent with the reported demographics for age and gender in the literature: IPF does appear to be prevalent across a wide age range and is more common in females (5). This gives the study favourable external validity.
The current audit data collection process by the hospital for injection therapy is deficient and does not record patient outcome measures despite this service being widely used with 749 injections over the three years of the study. The injections for IPF were also limited to single steroid or occasional sequential steroid injections. Whilst these are a recommended treatment for IPF, the extent and quality of audit data for non-surgical management of IPF is variable and at times contradictory (23). However, given the evidence in the literature search, it would be reasonable to include steroid injections into the pathway given that they may not be a long-term effective treatment but can also act as a diagnostic tool.
The literature also suggests that alcohol neuroablation injections produce satisfactory results in 89% of cases but the current care pathways do not advocate its use, and this may be due to the mixing of drugs, or concerns over the long-term effectiveness of the technique (24). The longevity of the technique has been criticised by Gurdezi, White, & Ramesh, 2013 but further researchers, Pasquali, et al., 2015, have disagreed with the findings and, therefore, the technique warrants inclusion in a care pathway, following the clinical technique and recommendations of Dockery, 1999 (24) (25) (26).
Other conservative or non-surgical options are offered by the local triage service and, at this time, the effectiveness of the treatments have a limited evidence base and require further investigation. Therefore, they have not been considered for inclusion in the secondary care pathway but are likely to be undertaken by Triage service prior to secondary referral. Moreover, the use of “generic anti-pronatory” insoles does not reflect the complexity of foot biomechanics and investigation into outcomes and patient satisfaction with bespoke orthosis (insoles) would be valuable in the formulation of a care pathway.
The use of ultrasound has its detractors but there is good evidence to suggest that guided injections are advantageous, and it would seem logical that a technique that allows the accurate visualisation of the placement of a drug into a tissue is beneficial (27) (28). This would also negate the risk of potential litigation and is primarily supported by advisory bodies (29).
The size of the IPF has been suggested as a possible factor in clinical outcomes for conservative care but this was not examined in this study. However, this data is available and a further study comparing the functional outcomes of surgery and patient satisfaction with the size of the IPF may provide constructive data for further development of the care pathway. If it assumed that the size of the IPF lesion is proportional to the duration of the condition then the timing of the surgery, and size of the lesion, may influence the potential outcomes.
The study also shows that the prevalence for IPF was more common in the 2/3 (77.5%) than the 3/4 intermetatarsal space (22.5%) and disagrees with previous literature (3). It also shows IPF to be prevalent in both spaces in 24% of patients in comparison to the 12% reported by Kasparek & Schneider, 2013, which is likely due to the high incidence of IPF in the 2/3 space (30). This may be attributed to the use of Ultrasound scans to support the clinical diagnosis and may represent an over diagnosis. However, diagnosis was also supported by isolated local anaesthetic and steroid injections before progressing to surgery, and a further study into the incidence and location of the pathology is suggested.
Again, in contrast to Kasparek & Schneider, 2013, the outcomes for double IPF excision were not significantly different to single IPF excision. There was also no significant difference in the post-operative follow-up duration and the patient satisfaction with the surgical outcomes (PSQ10), which is contrary to the findings of Lee et al, 2011 who suggests that the long-term results are not as favourable as the short term (31). This would suggest that the surgical technique employed in the study was effective at removing the IPF, and there were limited complications or regrowth of the lesions, for the majority of the patients, at an average of 130 weeks (range 48–203 weeks). Unfortunately, it is not possible to directly assess the individual surgical techniques of clinicians and this is likely to lead to some variance in outcomes.
In this study, the range and type of post-operative complications was not examined and no comparison can be drawn directly to the literature. However, if the PSQ10 is considered as a measure of patient satisfaction, then a score below 60 would represent a poor outcome. This was seen in 3 patients (3.3%), although it is not known if they underwent revision surgery. However, if the level of “acceptable satisfaction” is set at a PSQ10 of 70 then this figure rises to 7 (7.8%). These figures compare very favourably with the complication rate given in the literature, but this study does not identify the type of complications or reason for dissatisfaction. This may be a criticism of the study, but the extent of data collection required would have been prohibitive.
The MOxFQ domains results are not often reported in the literature but Flanagan & Reilly, 2016, do give the mean scores for the plantar incision approach on 42 patients (2). The scores obtained in this study are comparative pre-operatively and very slightly lower post-operatively to their study. When the MOxFQ domains in this study are analysed further to assess the effect of surgical approach (dorsal or plantar), there was no significant difference across the three domains and this agrees with the findings of Akermark et, 2008, although they did not present MOxFQ scores (7). There was also no significant difference between the site of the pathology (2/3 or 3/4) and the MOxFQ domain scores. Therefore, the care pathway cannot directly recommend which surgical approach is best and this would be based on the clinician’s preference.
In contrast, there was a significant difference in the patient satisfaction (PSQ10), with a lower outcome score associated with additional surgery, at the time of IPF excision. However, the MOxFQ scores were not significant for additional surgery. Unfortunately, the study was not able to differentiate if the lower satisfaction score was associated with the IPF excision, the additional surgery or a combination. It may be difficult for patients to appreciate the study requirements to answer questions directly related to the IPF only and not to other aspects of their surgery, which may have been more extensive. Furthermore, it may be that the few data outliers may be causing a skewing of the results, and therefore, there may be no significant difference with a larger sample. However, the care pathway could recommend that the excision of IPF with additional foot surgery may contribute to lower satisfaction levels but not functional scores. It is also suggested that further study into the outcomes of IPF excision with additional surgery against the outcomes from IPF excision only, at a National level, would be informative to the care pathway development in the future.
The MOxFQ and PSQ10 study data was compared to the National PASCOM reported outcomes (n = 1294) and there is marginal difference across all domains. In general, the patients in this study reported higher pre-operative and lower post-operative scores, indicating that the validity of this study data is supported against much larger numbers, and that the clinical technique is comparable to National standards. The National data was not investigated further to establish the number of dorsal or plantar incisions. Furthermore, this study reported a marginal increase in PSQ10 indicating that there was a slightly higher patient satisfaction in this study.
The relationship between the functional assessment scores of MOxFQ domains and the patient satisfaction score of PSQ10 shows that there is significant correlation between the two scores, so that a greater change in the MOxFQ outcome score (improved function) produces a higher patient satisfaction rate. This would also seem a logical correlation that the post-operative function and patient satisfaction are directly linked and helps validate the MOxFQ and the PSQ10.
The clinical care pathway developed in Fig. 3 is an adapted version from Thomas, et al., 2009, with the addition of relevant research findings to guide clinicians or patients in treatment choice (5). The yellow boxes show clinical history findings and the orange box gives the test recommendations. The green box shows the recommended treatments and the red box shows the differential diagnosis for IPF. The recommendation for an initial dorsal surgical approach was based on the research evidence and results of the study. However, this can be varied based on clinician’s personal preference and training.
The new clinical pathway (Fig. 3) compares well to the pathway suggested by Di Caprio et al, 2017 (6). However, their pathway reports inferior outcomes to those seen in this study: with lower success rates and a higher rate of unsatisfactory outcomes.