Accuracy of Percutaneous Lateral Release for Hallux Valgus: An Anatomic Study

Category: Bunion; Other Introduction/Purpose: Minimally Invasive Chevron and Akin (MICA) surgery is growing in popularity. There are now multiple studies comparing minimally invasive bunion correction to traditional open techniques. Many of these studies include percutaneous lateral soft tissue release using a specific blade, while others use an open technique. To our knowledge, there is no prior study confirming the accuracy of soft tissue release via percutaneous technique. Our objective was to evaluate the precision of the percutaneous release, both the structures released and percent release. Additionally, we identified adjacent nerves potentially at risk with a lateral soft tissue release, measuring their proximity to the incision and if they were damaged. Methods: Sixteen fresh frozen cadaveric foot specimens (8 paired limbs) underwent percutaneous lateral release utilizing a beaver blade under fluoroscopic guidance by two Foot and Ankle Fellowship Faculty who regularly perform the procedure. As described in early MICA technique papers by Redfern and Vernois, the blade was inserted into the plantar plate between the lateral sesamoid and the proximal phalanx. Then the blade was rotated laterally while the hallux was directed into varus. The goal was to release the lateral head of the Flexor Hallucis Brevis (FHB) without violating the Lateral Collateral Ligament (LCL). During our experiment the sesamoids were able to be successfully reduced after each release. The specimens were then dissected to reveal the extent of release of the FHB and LCL. Distance was measured between the blade path and the dorsal digital branch of the deep peroneal nerve, as well as the plantar digital nerve. Results: The FHB was at least partially released in 15/16 specimens. It was completely released in two specimens. 5/16 specimens had greater than 50% but less than 100% release and 8/16 specimens had <50% release. The LCL was completely intact in 8/16 specimens. It was partially released in 8/16 specimens (5 less than 50% released and 3 greater than 50% released). There was no correlation between percent of FHB release and the likelihood of LCL release. The dorsal cutaneous nerve was consistently near the path of the beaver blade, with a median distance of 2mm (range 1-8mm). However, the nerve was never found to be incised or transected. Likewise, the plantar nerve was never injured. Conclusion: This study sought to verify the effectiveness of percutaneous lateral release. We found the FHB to be at least partially released in all but one case, resulting in adequate clinical correction of sesamoid position. Full FHB release may not be necessary to achieve the clinical objective of sesamoid reduction. There was no correlation between percent of FHB release and concomitant release of the LCL, which demonstrates the challenge of an isolated FHB release. The dorsal cutaneous nerve was consistently near the blade path but was never injured, suggesting patients should be counseled regarding the risk. [Table: see text]

Biomechanical Evaluation of an Augmented Medial Capsular Repair for Hallux Valgus Surgery

Category: Bunion Introduction/Purpose: Hallux valgus correction is often complicated by recurrence in the setting of inadequate soft tissue balancing. The etiology of recurrence is multifactorial, but a key factor is the quality of the medial capsulorrhaphy which is limited by the quality and strength of the soft tissues. These soft tissues are often attenuated with loss of integrity due to the longstanding bunion deformity. We hypothesize that the medial capsulorrhaphy augmented with a suture tape construct will create a stronger repair. Methods: 8 unmatched and 16 matched cadaveric foot specimens were prepared. None had bunion deformities. The 8 unmatched samples were tested to determine the strength of the native medial capsule. The 16 matched samples underwent a longitudinal medial capsulotomy, eminence resection and medial capsulorrhaphy with or without augmentation with a suture tape construct. The samples were then tested in a biomechanics lab to determine the strength of the medial capsulorrhaphy. Results: The mean maximum moment for the intact, capsular repair and suture tape groups were 2.19 ± 0.639 Nm, 0.225 ± 0.074 Nm and 0.968 ± 0.581, respectively, P<0.001. The mean stiffness for the intact, capsular repair and suture tape groups were 8.06 ± 3.75 N/mm, 1.463 ± 0.553 N/mm, and 4.438 ± 4.035 N/mm, respectively, P=0.003. The suture tape provided 4.3x higher maximum moment and 3x higher stiffness compared to traditional medial capsulorrhaphy. Conclusion: The study demonstrates that a medial capsular repair augmented in a cadaveric model of medial capsulorrhaphy to provide greater strength compared to conventional suture repair. Recurrence of hallux valgus after surgery is multifactorial. One element is the strength of the medial imbrication and capsular repair at the 1st metatarsal phalangeal joint (MTPJ). The study presents biomechanical data demonstrating that this repair is strengthened with suture tape augmentation at the medial 1st MTPJ. This may result in decreased recurrence and potentially improved patient satisfaction following bunion correction.

Minimally Important Difference in the Foot and Ankle Outcome Score Among Patients Undergoing Hallux Valgus Surgery

Background: Patient-reported outcomes are increasingly used as measures of effectiveness of interventions. To make the tools more useful, therapeutic thresholds known as minimally important differences have been developed. The objective of this study was to calculate minimally important differences for the domains of the Foot and Ankle Outcome Score for hallux valgus surgery. Methods: The study was based on a retrospective analysis of patients newly scheduled for bunion correction surgery and completing patient-reported outcomes between October 2013 and January 2018. This study used anchor- and distribution-based approaches to calculate the minimally important difference for the instrument’s 5 domains. Confidence intervals were calculated for each approach. There were 91 participants included in the study. Results: Using anchor- and distribution-based approaches, the minimally important difference for the pain domain ranged from 5.8 to 10.2, from 0.3 to 6.9 for the symptoms domain, 8.3 to 10.3 for the activities of daily living domain, 7.4 to 11.1 for the quality of life domain, and from 7.0 to 15.7 for the sports and recreation domain. Small differences in the activities of daily living domain may be more clinically important for patients with better function. Discussion: The range of minimally important difference values for each domain indicate how the Foot and Ankle Outcome Score corresponded to bunion correction surgery. The sports and recreation domain showed considerable variability in the range of values and may be associated with the domain’s lack of responsiveness. Overall, most minimally important difference values for the domains of FAOS ranged from above 4 to below 16. Level of Evidence: Level III, retrospective comparative series.

Cost-Utility Study of the Economics of Bunion Correction Surgery

Background: Bunion correction surgery is a very common procedure to improve patients’ pain and physical function attributable to a misaligned first metatarsophalangeal joint. The objective of this study was to apply a health utility framework to estimate the cost utility of bunion correction surgery. Methods: Patients were prospectively recruited from the population of patients seen in a lower-extremity orthopedic clinic and scheduled for isolated bunion surgery. Participants completed EuroQoL’s EQ-5D(3L) to measure patients’ current general health preoperatively and 6 months postoperatively. Participants’ change in quality-adjusted life years (QALYs) were calculated by comparing the difference between postoperative utility values and preoperative utility values. The study had 95 patients representing 53% of eligible patients. Results: The mean preoperative utility value was 0.6816 and the mean postoperative value was 0.7451, a statistically significant difference denoting an improvement in self-reported health. The cost per QALY, assuming gains in health accrued for 15 years, was $4911 (the 95% confidence interval ranged from $4736 to $5088). The cost per QALY was highest among the oldest patients. Assuming gains in health accrued for 20 years, the cost per QALY was $3922. Conclusion: This study demonstrated that bunion correction surgery was inexpensive relative to its gains in health compared with commonly applied thresholds for women and men in all age groups, though the gains were not uniformly distributed across age categories. Future research should examine the impact of recurrence on the robustness of these findings. Level of Evidence: Level III, comparative study.

Relationship of Duration of Wait for Surgery and Postoperative Patient-Reported Outcomes for Hallux Valgus Surgery

Background: Little is known about the effect of delayed access to bunion correction (hallux valgus) surgery on patient-reported outcomes. The objective of this study was to measure the association between preoperative wait time for bunion correction surgery and postoperative patient-reported outcomes. Methods: This study prospectively recruited patients to complete preoperative patient-reported outcomes measuring depression, pain, and foot and ankle health, including the Patient Health Questionnaire–9 (PHQ-9); the pain intensity (P), interference with enjoyment (E) of life and general (G) instrument (ie, PEG); and the Foot and Ankle Outcome Score (FAOS), a condition-specific instrument. Patients complete the same patient-reported outcomes 6 months postoperatively. Regression models measured patient-reported outcomes as a function of wait time, adjusting for baseline health, age category, sex, comorbidities, and socioeconomic status. This study included 87 participants, a response rate of 53% among eligible patients. Results: Longer waits for bunion correction surgery, adjusting for other factors, were associated with smaller gains in health in 4 of the 5 domains of the FAOS. There was no relationship between postoperative depression and pain scores with duration of wait time, adjusting for patient characteristics. Conclusion: At the 6-month postoperative time point, prolonged preoperative wait times were detrimental to foot and ankle outcomes in 4 of the 5 domains of the foot and ankle–specific PRO. Policies for expediting access for symptomatic hallux valgus are warranted to mitigate poorer postoperative outcomes. Further study is required to understand if failure to improve is a permanent finding in the postoperative period. Level of Evidence: Level II, prospective comparative study.

Delayed access to bunion correction surgery

Category: Bunion Introduction/Purpose: Little is known about the effect of delayed access to bunion correction (Hallux Valgus) surgery on patient-reported outcomes. The objective of this study is to measure the association between delayed access to bunion correction surgery and post-operative patient-reported outcomes. Methods: This study prospectively recruited patients to complete pre-operative patient-reported outcomes measuring pain, depression and foot and ankle health. Patients complete the same patient-reported outcomes six months post-operatively. Linear regression models measured outcomes, adjusting for baseline health, age category, sex, comorbidities and socio-economic status. Results: This study included 74 participants, a response rate of 53% among eligible patients. Among participants, 58.9% underwent a Lapidus procedure, the remainder underwent a corrective osteotomy. There was no relationship between post-operative depression and pain scores with duration of wait time, adjusting for patient characteristics. Longer waits for bunion correction surgery, adjusting for other factors, were associated with smaller gains in health in four of the five domains of measurement of foot and ankle health. Conclusion: At the six-month post-operative time point, prolonged wait times were detrimental to foot and ankle outcomes in four of the five domains of the foot and ankle specific PRO. Policies for expediting access for symptomatic hallux valgus are warranted to mitigate poorer long-term outcomes.