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A Closer Look At Recent Innovations In Podiatry
Minimally invasive surgery has existed since the 1940s, lost favor with surgeons and has resurged in the last 20 years, notes Raquel Sugino, MS, DPM, FACFAS. As she says, in 2000, Bosch and colleagues showed good results using a 2-mm Steinmann pin for hallux valgus with a seven- to 10-year follow-up, and Portaluri also showed good results with minimally invasive bunion surgery.1,2
Dr. Sugino says the principles and goals of minimally invasive surgery are to obtain anatomic reduction and mechanical realignment in all three planes, to minimize soft tissue disruption, and to preserve vascularity. Additional goals are maintaining the stability of the osteotomy and to encourage early mobilization of the first metatarsophalangeal joint to restore a pain-free joint.
Who is a candidate for minimally invasive surgery? Dr. Sugino suggests those with hallux valgus that is mild, moderate (and sometimes severe) on radiographs, those with or without hypermobility, and those with little or no arthritis.
Since 2000, Dr. Sugino cites numerous innovations in minimally invasive techniques. Giannini developed the SERI (simple, effective, rapid, inexpensive) technique with a saw, not a burr, later reporting no nonunions with the technique in 1,000 feet.3,4 In 2014, Brogan introduced the third generation chevron with a Shannon burr, a 1.8-mm titanium pin and single screw fixation.5 Vernois and Refdern developed a minimally invasive chevron Akin for hallux valgus.6
Dr. Sugino notes the SERI technique utilizes a few K-wires and finishes with an osteotome. The surgeon would laterally translate the head and fixate it from distal to proximal with a Steinmann pin, to be held in place for 30 days.
Blood supply can be a concern in minimally invasive surgery, notes Dr. Sugino. Malal and colleagues found that constructing the chevron osteotomy with a long plantar limb exiting well proximal to the capsular attachment may decrease the postoperative prevalence of first metatarsal head osteonecrosis.7 Minokawa and colleagues checked the blood flow of 13 patients using laser Doppler flowmetry before and after minimally invasive surgery of the first metatarsal head, finding no significant change in pre-op or post-op blood flow, and no avascular necrosis at 12 months’ follow-up.8
Nerves can also be at risk in minimally invasive surgery, cautions Dr. Sugino. In a cadaver study, McGann and colleagues found following a minimally invasive distal chevron osteotomy, five of 10 cadavers had injured dorsal medial cutaneous nerves.9 Dr. Sugino says the results suggest a high learning curve with minimally invasive surgery, noting that the study used a surgeon who was inexperienced in minimally invasive techniques, who had watched videos and read articles about the procedure.
What does recent research reveal? In a study of 217 feet, Siddiqui and colleagues found no nonunions or major complications after percutaneous distal metatarsal osteotomy for hallux valgus.10 Patients achieved immediate weightbearing. In comparing chevron to transverse distal metatarsal osteotomy in cadavers, Aiyer and colleagues noted advantages to minimally invasive surgery.11 These include decreased operative time, fewer complications, better patient satisfaction and biomechanical strength.
For the post-op course following minimally invasive surgery, Dr. Sugino starts patients weightbearing as tolerated in a short controlled ankle motion boot or surgical shoe for the first two weeks. From weeks two to four, her patients bear weight as tolerated in a surgical shoe and begin range of motion at the first metatarsophalangeal joint. By week four, patients may wear tennis shoes with arch supports. At week 10, her patients may perform regular activities and impact activities if there is radiographic healing and no pain at the osteotomy sites.
How Innovations in Motion Analysis Change Patient Care
Visual gait analysis can provide valuable information about a patient’s biomechanics. However, the phenomenon is fleeting in real time, so measurement of gait can add great clinical value, according to Stephen Hill, PhD. Gait analysis technology has evolved from two-dimensional video recording with one camera, to early 3D video systems of five or six cameras, to multi-segmental foot models using 10 to 12 cameras featuring high resolution and high speed. In addition, a multi-camera system can incorporate floor-mounted force plates, and synchronized electromyography (EMG).
Dr. Hill emphasizes that gait analysis provides converging evidence with clinical findings, such as history, medical records, weightbearing, non-weightbearing, physical/biomechanical exams, range of motion, manual muscle testing, imaging, blood work, and other factors, to better understand a patient’s gait biomechanics.
Dr. Hill notes that electronic pressure walkways allow one to measure spatio-temporal parameters of gait such as step length and width, cadence, speed, cadence, toe-out angle, left-right symmetry, and variability. These walkways capture multiple left and right steps in one walk, include a graphic display of metrics, can incorporate webcam recording of lower limbs or whole body, synchronized with the footfall data, and are simple to set up with no instruments on the patient.
Dr. Hill advances that a more complete quantitative motion analysis of the lower limbs or even whole body during gait, can include 3D joint kinematics and kinetics, EMG, foot pressure distribution, and balance measures. In a recent review, Wren and colleagues found 3D instrumented gait analysis offers technical accuracy, diagnostics such as detailed interpretation of quantitative data, enhanced surgical planning, follow-ups, and improved outcomes for patients.12
Innovations in gait analysis include inertial monitoring units, which Dr. Hill points out are wireless, so patients may wear them under their clothes and have increased freedom of movement during activity. Patients can wear them on the head, sternum, arms, forearms, hands, pelvis, thighs, legs and feet. He notes an isokinetic dynamometer enables muscle strength testing at controlled angular velocities, and measures the force–velocity relationships of muscles. Dr. Hill says balance analysis measures volitional postural shifts, recovery responses to anterior/posterior perturbations, toes-up/toes-down perturbations, and vestibular head movements. New wearable technologies for gait analysis include compression garments with EMG electrodes, joint ankle sensors with smartphone apps, and instrumented socks and insoles, notes Dr. Hill.
Dr. Hill states that in private practice or a clinic, video recording assessment of walking and/or running is a simple application of modern technology to advance understanding and quality of care for your patients. He recommends the use of a treadmill or an unobstructed floor, and recording on a password protected/encrypted smart phone or tablet app. Two-dimensional videos should include a sagittal (left and right passes) and posterior view, and should utilize replay, slow motion and pause. Dr. Hill emphasizes that these visual recordings help patients understand their own gait, promoting their engagement in the course of treatment, and video has low requirements for cost, time and space.
The Subchondroplasty: What Have We Learned?
Bone marrow lesions are common in the knee and can lead to chronic pain and gait abnormality, notes Nicholas Todd, DPM. However, he says the clinical picture does not always correlate with radiographic evaluation; one patient may have bone on bone on radiographs but no pain, while another patient may have preservation of joint space but be in severe pain.
Dr. Todd notes MRI can demonstrate soft tissue causes of pain and bone damage with bone marrow lesions, which may not be appreciated on radiographs. As he notes, MRI can show bone marrow lesions via a hyperintense marrow signal, adding that the lesions are recognized on fluid-sensitive, fat-suppressed sequences.
Dr. Todd notes bone marrow lesions represent a healing response to trauma such as microtrabecular fractures of subchondral bone.13 Starr and colleagues found symptoms from bone defects occur due to irritation or disruption of the sensory nerves of bone marrow, and that bone has pain fibers.14 Rios and colleagues found bone marrow lesions to be common in the foot and ankle, often post-traumatic and related to avulsion fractures or contusions.15 Bone marrow lesions are highly symptomatic and can predict long-lasting pain.16
Who presents with bone marrow lesions? Dr. Todd notes patients are on average younger and more active. They present with chronic pain and disability, and have not responded to conservative care. He notes they may have presence of bone defects as seen on fat-suppressed MRI. Dr. Todd says conservative treatments in younger patients have shown mixed results in the long and short terms, and that these treatments have not directly addressed symptomatic subchondral bone defects.17
Subchondroplasty may be a viable treatment option for bone marrow lesions that falls in between conservative and surgical treatments, says Dr. Todd. In the hindfoot, he says subchondroplasty has applications in the tibial plafond, talus and calcaneal stress reaction. In the midfoot, subchondroplasty has applications for navicular stress reactions, and in the cuboid/cuneiform. Applications in the forefoot include the tarsal/metatarsal. Dr. Todd notes the most common foot and ankle applications for subchondroplasty are for bone defects associated with osteochondral lesions of the talus, bone marrow lesion defects, symptomatic subchondral cysts, and stress fractures.
Subchondroplasty is minimally invasive and assisted by fluoroscopy. Dr. Todd notes the procedure targets and fills subchondral bone defects with AccuFill Bone Substitute Material (Zimmer Biomet), which is a nanocrystalline, porous, injectable calcium phosphate. He notes surgeons usually perform the procedure with arthroscopy to visualize the joint, adding that sometimes an open or mini-open procedure may be necessary to access the joint.
Preoperative planning for subchondroplasty is based on MRI findings. Dr. Todd notes T1 MRI may show the bone lesion and can estimate fill volume, while T2 will show the bone marrow lesion. For most lesions, he says an implant of 0.25–2 cc is adequate. The working time for AccuFill is 15 minutes and it is injectable under low pressure. Dr. Todd says it flows uniformly into trabecular bone, is hydrophilic and isothermically sets in 10 minutes. He adds that AccuFill has a total porosity of 55 percent and an average compressive strength of about 10 MPa, similar to average cancellous bone.
Making Sure Your Hospital Gets The Products You Need
What do you do when there is a new product you like but your facility does not want to add it? Devon Glazer, DPM, FACFAS, says most of the time, hospitals won’t approve a product because it is a new technology, has a high cost, or is not on contract, but there are ways to work around this.
First, Dr. Glazer says your product representative should make first contact with the facility and report back to you. The rep should collect all the data you need for any forms you need to fill out. Then Dr. Glazer says you should schedule a visit with your OR manager and ask the following: why specifically you can’t use the product, what the process is at the facility, and what are the approved products and the cost for those products. He cautions that one should not try to negotiate at that point. For the OR manager, should collect facts on the procedure for which you’re using the product, get an average cost and an average time for the procedure use.
Dr. Glazer notes with new technology, one would submit to the Value Analysis Committee why the product is proprietary, an important factor for approval, and the committee will decide if it is approved. One should also explain to the Value Analysis Committee the opportunity that the new product provides, any cost saving, any better clinical outcomes from the product. He notes one would also explain any issues with the existing product. He says the committee will look at data, literature review and third-party evaluations and comments.
With a new technology, Dr. Glazer suggests asking a no-charge trial case from the vendor demonstrating the product. He says one should highlight any reduced cost, asking the vendor for contracted rates. If the new product is not cheaper, emphasize improved results, saved OR time or if the new product encompasses multiple procedures, according to Dr. Glazer.
What if the product is not on contract? Dr. Glazer says this does not have to be the “kiss of death.” He says most hospitals have a contracting time and follow surgeon comment, and will may have to champion the product at the next contract time. Some facilities will have a 90/10 on-contract rule and may be able to use an off-contract product if 90 percent of their other products are on contract.
In an email or a letter, Dr. Glazer suggests highlighting the cost of the product, safety, time saved, and if the product is proprietary. He says one should note whether the product will yield more billable procedures, and note difficulties of other technologies that may have failed.
After sending the letter, Dr. Glazer says the hospital may give you a trial use of the product and you should document how the trial went. The Value Analysis Committee will send a request for proposal and the product may go through a final analysis process before its official approval.
Disclosures (Dr. Glazer): Product design for Extremity Medical, clinical trainer for SEAL DNE, clinical educator for Tenex Health
References
1. Bosch P, Wanke S, Legenstein R. Hallux valgus correction by the method of Bosch: a new technique with a seven-to-ten-year follow-up. Foot Ankle Clin. 2000;5(3):485-98S.
2. Portaluri M. Hallux valgus correction by the method of Bosch: a clinical evaluation. Foot Ankle Clin. 2000; 5(3):499–511.
3. Giannini S, Ceccarelli F, Bevoni R, Vannini F. Hallux valgus surgery: the minimally invasive bunion correction (SERI). Techniques Foot Ankle Surg. 2003; 2(1):11–20.
4. Giannini S, Faldini C, Nanni M, et al. A minimally invasive technique for surgical treatment of hallux valgus: simple, effective, rapid, inexpensive (SERI). Int Orthop. 2013; 37(9):1805–13.
5. Brogan K, Voller T, Gee C, et al. Third-generation minimally invasive correction of hallux valgus: technique and early outcomes. Int Orthop. 2014; 38(10):2115–21.
6. Vernois J, Redfern DJ. Percutaneous surgery for severe hallux valgus. Foot Ankle Clin. 2016; 21(3):479–93.
7. Malal JJG, Shaw-Dunn K, Kumar S. Blood supply to the first metatarsal head and vessels at risk with a chevron osteotomy. J Bone Joint Surg Am. 2007; 89(9):2018–22.
8. Minokawa S, Yoshimura I, Kanazawa K, et al. Effect of minimally invasive distal first metatarsal osteotomy on blood flow of the metatarsal head. J Orthop Sci. 2019; 24(4):693–6.
9. McGann M, Langan TM, Brandao RA, et al. Structures at risk during percutaneous extra-articular chevron osteotomy of the distal first metatarsal. Foot Ankle Spec. 2021; 14(1):19–24.
10. Siddiqi NA, LaPorta G, Walsh A, et al. Radiographic outcomes of a percutaneous, reproducible distal metatarsal osteotomy for mild and moderate bunions: a multicenter study. J Foot Ankle Surg. 2019; 58(6):1215–22.
11. Aiyer A, Massel DH, Siddiqui NA, Acevedo JI. Biomechanical comparison of two common techniques of minimally invasive hallux valgus correction. Foot Ankle Int. 2021; 42(3):373–80.
12. Wren TAL, Gorton GE, Õunpuu S, Tucker CA. Efficacy of clinical gait analysis: A systematic review. Gait Posture. 2011; 34(2):149–153. Update presented at Gait and Clinical Movement Analysis Society Conference, June 8–9, 2021.
13. Eriksen EF, Ringe JD. Bone marrow lesions: a universal bone response to injury? Rheumatol Int. 2012. 32(3):575–84.
14. Starr AM, Wessely MA, Albastaki U, et al. Bone marrow edema: pathophysiology, differential diagnosis, and imaging. Acta Radiol. 2008; 49(7):771–86.
15. Rios AM, Rosenberg ZS, Bencardino JT, et al. Bone marrow edema patterns in the ankle and hindfoot: distinguishing MRI features. AJR Am J Roetgenol. 2011; 197(4):W720–9.
16. Zanetti M, Steiner CL, Seifert B, Hodler J. Clinical outcome of edema-like bone marrow abnormalities of the foot. Radiology. 2002; 222(1):184–8.
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