A systematic review of the claw toe deformity: What is known and what is needed apart from surgical procedures.

The claw toe deformity is a painful condition that mainly affects the adult population. Although there are many different treatments to solve the deformity, there is no optimal procedure to restore the normal foot mechanics. The objective of this review was to identify the technical features of the kinematic evaluation methods used in patients with claw toes. Furthermore, the aim of this review was to clarify what is known and what is needed apart from the surgical procedures to correct the claw toe deformity, with the purpose of reducing risk factors of falling in elderly people. A search in electronic databases, such as Scopus (n = 78), Google Scholar (n = 705) and ScienceDirect (n = 290) was conducted. There were seven articles (43.75%) related to the fixation (arthrodesis) of proximal and distal interphalangeal joints, one article (6.25%) describes the correction of the claw toe through plantar plate tenodesis and release of collateral ligaments, four articles (25%) describe the procedure of tendon transfer, one article (6.25%) describes flexor digitorum brevis tenotomy and a proximal interphalangeal joint arthrolysis, and another article (6.25%) presented the impact of partial phalanx osteotomy to treat the claw toe deformity. In conclusion, the review indicates that there are several studies related to the treatment or correction of claw toe deformity. However, there is a lack of knowledge of the postsurgical effects of treating claw toe condition, especially in the structural mechanics (plantar pressure distribution, stability, gait, foot mechanics and so on) of the foot after the correction of the claw toe deformity. The analysis of the foot mechanics after the correction of the claw toes has to be paramount to determine the benefits of the correction.

Neuropathic Deformities of the Lesser Toes.

Neuropathic deformities of the lesser toes refer to a variety of neuromuscular disorders in which a stiff lesser toe deformity is encountered. Claw toes, hammer toes, and mallet toes can be found. Each deformity is better described as which joint of a particular toe is in a flexed or extended position. This information guides the surgeon to which joint should be addressed and what additional soft tissue procedure may be needed. Interphalangeal joint fusions are the procedure of choice, together with extensor or flexor tenotomies. Good results can be expected, with low revision rates.

Principles of Lesser Toe and Metatarsophalangeal Joint Reconstruction for Complex and Revision Surgery of the Forefoot.

Successful lesser toes and metatarsophalangeal (MTP) joint reconstruction must withstand substantial biomechanical loads from standing, walking, and exercise. While complications following lesser toe and MTP reconstruction are common, limited literature addresses revision surgeries for complications including recurrence. Numerous complications of surgery for toes and lesser MTP joints can be managed or improved through revision surgery, but not all complications can be prevented or resolved. This review focuses on understanding the general principles and surgical techniques for hammer toe and lesser MTP reconstruction to apply effectively in both primary and revision surgeries.

Influence of the biomechanical evaluation of rupture using two shapes of same intramedullary implant after proximal interphalangeal joint arthrodesis to correct the claw/hammer pathology: A finite element study.

We used finite element analysis to study the mechanical stress distribution of a new intramedullary implant used for proximal interphalangeal joint (PIPJ) arthrodesis (PIPJA) to surgically correct the claw-hammer toe deformity that affects 20% of the population. After geometric reconstruction of the foot skeleton from claw toe images of a 36-year-old male patient, two implants were positioned, in the virtual model, one neutral implant (NI) and another one 10° angled (10°AI) within the PIPJ of the second through fourth HT during the toe-off phase of gait and results were compared to those derived for the non-surgical foot (NSF). A PIPJA was performed on the second toe using a NI reduced tensile stress at the proximal phalanx (PP) (45.83 MPa) compared to the NSF (59.44 MPa; p < 0.001). When using the 10°AI, the tensile stress was much higher at PP and middle phalanges (MP) of the same toe, measuring 147.58 and 160.58 MPa, respectively, versus 59.44 and 74.95 MPa at corresponding joints in the NSF (all p < 0.001). Similar results were found for compressive stresses. The NI reduced compressive stress at the second PP (-65.12 MPa) compared to the NSF (-113.23 MPa) and the 10°AI (-142 MPa) (all p < 0.001). The von Mises stresses within the implant were also significantly lower when using NI versus 10°AI (p < 0.001). Therefore, we do not recommend performing a PIPJA using the 10°AI due to the increase in stress concentration primarily at the second PP and MP, which could promote implant breakage.

How Important Is a Lesser Metatarsal Osteotomy in Preventing Second Hammertoe Recurrence?

Hammertoes with greater preoperative transverse plane deformity are more likely to recur after corrective surgery; however, it is unclear whether this represents an inherent (fixed, nonmodifiable) risk, or whether steps can be taken intraoperatively to mitigate this risk. In this study, we examined whether transverse plane transposition and/or shortening of the second metatarsal during second hammertoe surgery influenced recurrence. We performed a secondary analysis of pre-existing data from patients that had previously undergone second hammertoe surgery at our institution between January 1, 2011 and December 31, 2013. One hundred two patients (137 toes) were followed for a mean 28 ± 7.8 months postoperatively. Thirty-seven toes required, at the surgeon's discretion, an additional/concomitant Weil metatarsal osteotomy. Magnitude of transverse plane transposition and shortening of the second metatarsal, and joint angular measurements were obtained from the second metatarsophalangeal joint on weightbearing AP radiographs preoperatively and at 6 to 10 weeks postoperatively. Cox regression analysis was used to identify predictors of hammertoe recurrence using these new variables and a set of known predictors. In the final regression model, failure to establish a satisfactory postoperative metatarsal parabola (i.e., long second metatarsal; Nilsonne values <-4 mm, multivariate hazards ratio [HR] 1.96, p = .097), and intraoperative lateral transposition of the metatarsal head (multivariate HR 3.45, p = .028) seemed to confer additional risk for hammertoe recurrence. We conclude that shortening osteotomies may be assistive in some individuals, while further inquiry is still needed to determine whether similar benefits can be derived from medial head transposition in medial toe deformities.

Minimally Invasive Versus Open Hammertoe Correction: A Retrospective Comparative Study.

Hammertoe deformity is a common forefoot pathology, characterized by a progressive deformity with dorsiflexion of the proximal phalanx on the metatarsal head at the metatarsal phalangeal joint (MTPJ) and plantarflexion of the intermediate phalanx on the proximal phalanx at the proximal interphalangeal joint (PIPJ). While there is literature available discussing open techniques for hammertoe correction, there is a lack of publications discussing minimally invasive techniques, therefore the objective of this retrospective comparative study is to evaluate minimally invasive versus open hammertoe surgery in terms of time to osseous union, complications, recurrence, and return to full activity. Sixty eight feet among 41 patients met the inclusion criteria and were surveyed. Among the 68 feet, 54 feet (124 toes) underwent minimally invasive hammertoe correction and 14 feet (22 toes) underwent open hammertoe correction. Time to osseous union (weeks) in the MIS group was 8.76 ± 2.31 weeks with similar outcomes to the open group with union at 8.42 ± 2.31 (p = .65). Return to activity (weeks) was 10.47 ± 3.45 in the MIS group and 9.92 ± 3.03 in the open group with no statistical significance (p = .62). There was 4 recurrent hammertoe deformities in the MIS group (3.23%) with no recurrent hammertoes in the open group (0%). In the MIS group 5 hammertoes had unplanned hardware removal (4.03%) compared to 0 in the open group. There was no statistical significance for both recurrence and unplanned hardware removal (p = 1). Overall, we concluded that both techniques are equivocal with no detectable statistical difference.

Treatment of Dynamic Claw Toe Deformity Through Lengthening of the Flexor Tendons of the Hallux and Toes at the Midfoot Level.

The claw toe deformity is characterized by the flexion of interphalangeal joints (IPJs) with hyperextension of the metatarsophalangeal (MTP) joint. It can be flexible and reducible or rigid and irreducible, or dynamic. The most common cause of dynamic claw toes is a neurological disorder, like sequelae of an ischemic contracture of the muscle belly after a compartment syndrome. Most of the surgical techniques require multiple procedures and may be associated with complications such as toe stiffness, persisting metatarsalgia, and toe malalignment. The aim of this study is to present an option for the surgical treatment of the dynamic claw toe deformity, by simultaneous tenodesis and lengthening of the flexor hallucis longus (FHL) and flexor digitorum longus (FDL) tendons at Henry's knot through a single midfoot incision.Levels of Evidence: V; Therapeutic Study; Expert Opinion.

The use of an Intra-medullary fusion system in hammer toe surgery; mid-term follow-up.

Objectives: To assess the efficacy of a new hammer-toe locking fusion system. METHODS: The retrospective study was conducted at Kutahya Evliya Çelebi Education and Research Hospital, and comprised data from March 2014 to January 2017 of patients of either gender with hammer toe deformity. The American Orthopaedic Foot and Ankle Society and visual analogue scale scoring systems were used. Radiological evaluation was also used to determine the lateral interphalangeal angle measurements. All patients were subjected to hammer toe surgery using new two-block interlocking fusion system, and were followed up for about 2 years. SPSS 25.0 for windows was used for analysis. RESULTS: According to gender, 13(65%) of patients were female and 7(35%) of patients were male. The overall mean age was 51.5±16.31 years (range: 20-72 years). Of all the surgeries, 9(45%) were performed on the right foot, and 11(55%) on the left foot. The follow-ups ranged 21-32 months. Compared to baselines values, American Orthopaedic Foot and Ankle Society scale and visual analogue scale scores significantly improved post intervention (p<0.05). CONCLUSIONS: Significantly favourable outcomes were noted, indicating the efficacy of the fusion process.

Claw Toe Deformity After Revision Hip Arthroscopy with Concomitant Periacetabular Osteotomy: A Case Report.

CASE: A 22-year-old woman underwent revision right hip arthroscopy (HA) with concomitant periacetabular osteotomy (PAO). The total procedure time was 5.5 hours. After completion of the 3 hour HA portion, the traction boots were loosened. Eleven weeks postoperatively, she developed a left claw toe deformity. After failed conservative management, she underwent lengthening of the left flexor hallucis longus and flexor digitorum longus tendons. CONCLUSION: This is a case of a claw toe deformity after revision right HA with concomitant PAO. The possibility of this complication should be considered in cases with prolonged intraoperative times because of the use of traction boots.

Novel Extramedullary Fixation Device for Hammertoe Correction: A Retrospective Review of 100 patients.

Classically, one of the more common treatment options for rigid hammertoe correction consists of end-to-end arthrodesis stabilized by temporary Kirschner wire (K-wire) fixation maintained until osseous consolidation or complication necessitating premature removal. However, single K-wire fixation allows for axial rotation which results in loss of compression at the arthrodesis site. To counteract this, intramedullary implants were designed to provide fusion site stability in all planes negating extra-skeletal extension of the wire. Nevertheless, manual pressfit implants arguably offer less reliable positioning of the fusion site in a true end to end orientation due to variation in intramedullary stem placement compared to direct visualization with dorsal plating. Larger diameter implants create an osseous void at the bony interface reducing the potential of true bony union. Hammertoe implant failure poses a unique and challenging salvage scenario which can ultimately end in amputation. Extramedullary fixation is uniquely designed to merge both benefits of K-wires and intramedullary implants while eliminating inadequacies of each. A total of 100 patients who underwent 150 rigid hammertoe corrections with an extramedullary implant were retrospectively reviewed. The mean postoperative follow-up was 12.6 months (range 12-18 months). Overall, 94 of 100 patients (94%) achieved radiographic union, defined by 2 or more bridged cortices at the arthrodesis site without signs of hardware breakage or signs of lucency across one or more fusion sites at a mean 8.8 weeks (range 7-10 weeks). This study demonstrated excellent results in regards to postoperative arthrodesis when utilizing an extramedullary implant for hammertoe deformity correction. This device minimizes osseous deficit by extramedullary application, all while augmenting intramedullary K-wire fixation.

Biomechanical comparison of different implants for PIP arthrodesis.

BACKGROUND: Surgical correction of hammertoe deformities with arthrodesis of the proximal interphalangeal joint (PIP) is one of the most frequent forefoot procedures. Recently, new intramedullary fixation devices for PIP arthrodesis have been introduced. The aim of this study was to compare a newly developed absorbable intramedullary implant made of magnesium (mm.PIP), an already available intramedullary implant made of titanium (PipTree), and the classical Kirschner-wire (K-wire). METHODS: The three intramedullary devices (mm.PIP, PipTree, and K-wire) for PIP arthrodesis were compared. A classical arthrodesis of the PIP joint was performed on fifty-four composite synthetic bone pairs. After arthrodesis, torsional load, weight-bearing and cyclic load tests were performed, and stability of the synthetic bone pairs was analyzed. RESULTS: The mm.PIP was the most torsion resistant (mm.PIP vs. PipTree and K-wire, p < 0.001). The PipTree showed the best overall stability during cyclic weight-bearing simulation (PipTree vs. mm.PIP and K-wire, p < 0.001). K-wire demonstrated the highest breaking loads during bending tests (K-wire vs. mm-PIP and PipTree, p < 0.001). CONCLUSION: Biomechanical properties of two new intramedullar implants, the bioresorbable mm.PIP made of magnesium and the PipTree made of titanium, were found to be comparable to the biomechanical properties of a K-wire which is commonly used for this procedure. Future work should be directed towards a clinical assessment of the bioabsorbable fixation devices for hammertoe procedures.

Symptomatic Hammertoes Treatment Comparison: Peg-in-Hole Arthrodesis Versus End-to-End Screw Fixation.

Proximal interphalangeal (PIP) arthrodesis technique utilizing the peg-in-hole arthrodesis was founded to avoid the use of retained internal fixation implants and thereby potentially decrease the concern of hardware complication. The specific aim of this study was to report the complication rates of the modified peg-in-hole arthrodesis technique and the end-to-end arthrodesis with single screw fixation technique for correcting symptomatic hammertoe deformities in lesser digits. This retrospective chart review included patients who underwent surgical hammertoe correction of lesser digits between the dates of January 2012 and December 2019. Patient demographic data and charts were reviewed to evaluate need for revision including screw/pin removal and complications related to corrective surgery. Five hundred ninety-three symptomatic hammertoe deformity cases (443 female, 150 male) were identified, with 113 cases (88 female, 25 male) treated with peg-in-hole arthrodesis technique and 480 cases (355 female, 125 male) treated with end-to-end arthrodesis with a single screw technique. The deformity recurrence rate was not significantly different between the two techniques (peg-in-hole: 10%, end-to-end: 13%, p = .428). There were 97 cases with postoperative complications that required re-operation (peg-in-hole: 7 cases, end-to-end: 90 cases) with the majority detected at <6 months. There was no statistically significant difference in reoperation rate between the peg-in-hole technique and the end-to-end arthrodesis technique reoperated with reasons excluding simple screw removal (p = .068). This study tended to show these two arthrodesis techniques have equivalent risks and similar success in bone healing; however, the peg-in-hole arthrodesis technique offers an advantage that does not result in retained hardware.

Pediatric Hammertoe Recurrence-Considerations for Revision Surgical Technique and Hypoperfusion Management: A Case Report.

CASE: A 7-year-old girl presented with a recurrent hammertoe deformity causing pain with shoe wearing after a prior corrective surgery. Surgical revision required a unique approach that included a staged corrective osteotomy of the proximal phalanx because of hypoperfusion management and the application of a rotational skin flap previously described for camptodactyly correction in the hand to avoid harvesting a skin graft. CONCLUSION: Revision surgery for recurrent pediatric hammertoe deformity requires a heightened awareness of the risk for toe hypoperfusion and subsequent wound closure challenges.

Medullary Screw Fixation and the Pilot Hole Technique for the Correction of Hammertoe Deformity.

BACKGROUND: Historically, Kirschner wires have been used for fixation of the interphalangeal joints of the toe. They are still the most popular form of fixation, likely due to training patterns, ease of use, and decreased cost. Recently, numerous medullary fixation devices have become available, including medullary screws. METHODS: After performing various forms of fixation for the correction of toe deformities, the authors have developed a new pilot hole technique for screw fixation advancing on the previously described pilot hole technique for Kirschner wire fixation. RESULTS: The authors have found this method to provide intraoperative confidence that improper hardware placement has not occurred. CONCLUSIONS: The pilot hole technique described in this paper is a safe and effective technique that may be employed by surgeons using screw fixation for the treatment of hammertoe deformities. The technique reduces the possibility of surgeon error and helps to ensure that the screw is properly placed within the phalanges when properly employed.

Conservative Approach in the Management of Lesser Toe Deformities in Older Adults.

BACKGROUND: Toe deformities are common foot abnormalities in older adults, contributing to functional disability, loss of balance, falls, and pressure lesions. The aim of this study was to evaluate the effectiveness of the custom-made molded silicone toe prop in distributing apical and metatarsophalangeal joint peak plantar pressures and force-time integral in toe deformities, including hammertoes and claw toes, and to observe any difference in pressures between flexible and rigid toe deformities. METHODS: A prospective quasi-experimental pretest/posttest study was conducted including 20 "healthy" older adults with a hammer or claw toe at the second digit. Ten subjects presented with a flexible toe and 10 subjects presented with a rigid toe. A molded silicone toe prop was devised for each participant. Dynamic plantar pressure measurements were taken/recorded before applying the toe prop and after the toe prop was placed under the toe. RESULTS: Significant differences in mean peak plantar pressure and pressure-time integral were observed at the apex of the second toe in both the flexible and rigid toe deformity when using a molded silicone toe prop. At the metatarsophalangeal joint, pressures were significantly reduced in the rigid toe deformity but not in the flexible toe deformity. CONCLUSIONS: Silicone molded toe props were found to be effective in reducing peak pressure and pressure-time integral on the apex of the second digit in participants with both flexible and rigid claw or hammertoe deformity. Lesser toe deformities may be the cause of several foot complications, including pain on walking, corns, difficulty in wearing footwear, possible ulcerations caused by increased pressure at the apices of the toes, and other comorbidities, that could possibly lead to falls in older adults and thus need to be addressed appropriately.

Intraosseous Technique for Correction of Hammertoe Deformity.

Hammertoe deformities are among the most common conditions treated by foot and ankle surgeons. Many different types of proximal interphalangeal joint arthrodesis fixation techniques have been used. These include implant fixation, absorbable fixation, screw fixation, two-pin fixation, and single-Kirschner wire fixation. Each of these has their own set of associated advantages and disadvantages. One of the most common techniques to address hammertoe deformity is the use of Kirschner wires. Although Kirschner wires have been reliable and produced good outcomes, there are some drawbacks associated with their use. Some disadvantages include wire failure (bending/breaking), infection, and patient anxiety associated with removal. One of the more challenging aspects with using a single Kirschner wire for fixation is stability. Pistoning and rotational instability may occur with single-Kirschner wire use. Both pistoning and lack of rotational control can lead to nonunion, fibrous union, malunion, and ultimately patient dissatisfaction. The suturedesis technique is a surgical option that may be considered when a surgeon attempts to address these disadvantages. The authors believe this technique can adequately bring stability to the frontal plane and eliminate pistoning, which may lead to better fusion rates, better postoperative alignment, and better patient satisfaction. This article outlines the authors' surgical technique of suturedesis in correcting hammertoe deformity.

Hammertoe correction with wire fixation of varying length.

BACKGROUND: Proximal interphalangeal (PIP) joint fusion with Kirschner (K) -wire fixation remains a popular strategy for hammertoe correction. This study was performed to evaluate the effect of length of wire fixation on clinical outcomes. METHODS: A retrospective review of all hammertoe reconstructions by a single surgeon was performed. Wire length was chosen at the surgeon's discretion. Outcomes were assessed with metatarsophalangeal (MTP) congruency, pin complications, and PIP union. RESULTS: 157 toes underwent reconstruction. Seventy had wires that spanned the MTP and 87 that did not. Wire breaks were significantly more common with longer wire fixation (P = .024). MTP incongruency was significantly more common in the MTP group (P = .014). CONCLUSION: Pin breakage was rare and only occurred in the MTP group. MTP incongruence was significantly more common in the MTP group but may not reflect surgical technique. PIP union was more common with longer wire fixation but is not clinically significant. LEVEL OF EVIDENCE: III.

Fiber-reinforced fixation implant for proximal interphalangeal joint arthrodesis shows advanced implant bio-integration at 2-year follow-up.

BACKGROUND: A bio-integrative fiber-reinforced implant (OSSIOfiber® Hammertoe Fixation Implant, OSSIO Ltd., Caesarea, Israel) for proximal interphalangeal joint (PIPJ) correction-arthrodesis showed partial bio-integration at 1-year follow-up (1FU) in a previous study. The study was prolonged to assess the bio-integration at 2-year-follow-up (2FU). METHODS: Twenty-four patients with proximal interphalangeal joint (PIPJ) correction-arthrodesis using the fiber-reinforced implant and analysed at 1FU, completed 2FU. Follow-up included clinical examination, patient reported outcomes, radiographs, MRI and bio-integration scoring. Results were compared between the 1FU and 2FU (paired t-test). RESULTS: Radiographs confirmed fusion in 96 % (n = 23) at 2FU (1FU, 92 % (n = 22)). Implant was no longer visible in 21 % (n = 5), partially visible in 33 % (n = 8), and fully visible in 46 % (n = 11)(1FU, fully visible 100 % (n = 24)). The border between implant and surrounding bone was scored not visible in 88 % (n = 21) and partially visible in 12 % (n = 3) (1FU, border partially visible 100 % (n = 24)). There were no cyst formation or fluid accumulation findings 1FU/2FU. Mild bone edema was detected in 4 % (n = 1) (1FU, 29 % (n = 7)). None of the edema findings were considered as adverse implant related. The mean bio-integration score was 9.71 ± 0.69 at 2FU (1FU, 7.71 ± 0.46). The parameters of border between implant and bone and bone edema further improved at the 2FU compared to the 1FU, total bio-integration score was also higher at 2FU than 1FU (each p < 0.05). CONCLUSIONS: This study demonstrates 96 % PIPJ fusion rate and increased bio-integration from 1FU to 2FU, reaching advanced bio-integration of the fiber-reinforced implant at 2FU.

Complications of Lesser Toe Surgery: How To Avoid Them before Surgery and How To Assess and Treat Them When They Have Occurred.

Complications following lesser toe surgery are challenging to manage. The keys to treatment of any of these conditions are, first, to try to avoid them through identification of patient- and surgeon-related variables that contribute to their development and, second, following the occurance of a complication, to understand what can and cannot be corrected with surgical and nonsurgical management. This review provides a comprehensive assessment of current literature, demonstrates best practices and approaches to lesser toe complications, and provides an illustration of clinical examples.

The influence of concomitant hammertoe correction on postoperative outcomes in patients undergoing hallux valgus correction.

BACKGROUND: Patients with hallux valgus often develop secondary hammertoe deformities of the lesser toes. Operative management of bunions with hammertoe can be more extensive; however, it is unclear whether this affects patient-reported outcomes. The aim of this study was to compare postoperative patient-reported outcome measures and radiographic outcomes between patients who underwent isolated bunion correction and patients who underwent simultaneous bunion and hammertoe correction. METHODS: Preoperative, postoperative, and change in Patient-Reported Outcomes Measurement Information System (PROMIS) scores were compared between patients who underwent isolated hallux valgus correction and those who underwent concomitant hammertoe correction. Radiographic measures including hallux valgus angle (HVA), intermetatarsal angle (IMA), distal metatarsal-articular angle (DMAA), and Meary's angle were also compared. Targeted minimum-loss estimation (TMLE) was used for statistical analysis to control for confounders. RESULTS: A total of 221 feet (134 isolated bunion correction, 87 concomitant hammertoe correction) with a minimum of 12 months follow-up were included in this study. Both cohorts demonstrated significant improvements in the physical function, pain interference, pain intensity, and global physical health PROMIS domains (all p < 0.001). However, patients in the concomitant hammertoe cohort had significantly less improvements in pain interference and pain intensity (p < 0.01, p < 0.05 respectively). The concomitant hammertoe cohort also had significantly higher postoperative pain interference scores than the isolated bunion cohort (p < 0.01). Radiographic outcomes did not differ between the two groups. CONCLUSION: While both isolated bunion correction and concomitant hammertoe correction yielded clinically significant improvements in patient reported outcomes and normalized radiographic parameters, patients undergoing simultaneous bunion and hammertoe correction experienced substantially less improvement in postoperative pain-related outcomes than those who underwent isolated bunion correction.