Digital arthrodesis

Pressure-Relief Effect of Post-Op Shoes Depends on Correct Usage While Walking

Post-op shoes (POSs) are commonly used after forefoot surgery to protect the surgical site. However, there are insufficient data on their impact on forefoot load during the rollover phase of walking. This study aims to analyze the effects of a commonly used POS on plantar pressures under the forefoot and to assess whether improper usage could affect pressure patterns. Sixteen healthy volunteers underwent three different walking tests on a straight tartan track. The test setting included walking barefoot, as well as normal walking and a modified heel-accentuated "limping" gait while wearing a common POS. The pressure distribution over the forefoot regions of interest was measured using sensor insoles and a pressure-measuring plate on the ground. Results show that only the heel-accentuated "limping" gait in the POS led to a significant reduction in pressure values over all anatomical regions compared to the normal barefoot gait. Furthermore, higher pressure values were found over the lesser toes during normal walking in the POS compared to normal barefoot walking. The findings highlight that the protective function of a POS relies on proper use, specifically the correct gait pattern. If used incorrectly, POS may even have unfavorable effects on the pressure on the operated forefoot and possibly even increase the risk of delayed healing or complications in comparison to barefoot walking. Therefore, strategies such as patient training in proper walking techniques should be incorporated into postoperative care.

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.

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.

Hammer Toe Correction with Proximal Interphalangeal Joint Arthrodesis

Background

First described by Soule in 1910, arthrodesis of the proximal interphalangeal joint is a common operative method of treatment of hammer toe, or fixed-flexion deformity of the proximal interphalangeal joint of the lesser toes1. The deformity is often caused by imbalance in intrinsic and extrinsic muscle function across the interphalangeal joint and metatarsophalangeal joint2,3, which can be effectively addressed through proximal interphalangeal joint straightening and arthrodesis in conjunction with soft-tissue balancing of the metatarsophalangeal joint.

Description

Following longitudinal skin incision over the joint, a transverse extensor tenotomy and capsulotomy reveal the proximal interphalangeal joint and provide appropriate exposure of the head of the proximal phalanx. With the soft tissues protected, the proximal and middle phalanges undergo resection of the articular surfaces to allow osseous apposition. This step can be performed with a rongeur sagittal saw or with osteotomes4,5. The head of the proximal phalanx is resected proximal to the head-neck junction, and the proximal portion of the middle phalanx is removed to expose the subchondral bone. Often, there is a dorsal contracture of the metatarsophalangeal joint that is elevating the toe, which is addressed with use of a longitudinal incision over the metatarsophalangeal joint, a Z-lengthening of the long extensor tendon to the toe, and a subsequent capsulectomy. If there is an angular component to the deformity, the collateral ligaments are released from the metatarsal neck, and the toe can be balanced. If there is residual subluxation of the joint that is incompletely corrected by soft-tissue procedures, a metatarsal osteotomy should be considered. Fixation is then performed with use of a smooth Kirschner wire. The wire is inserted from the middle phalanx out the tip of the toe and subsequently inserted retrograde across the proximal interphalangeal joint, often into the metatarsal head and neck, holding the metatarsophalangeal joint in appropriate position. This step can also be completed with use of novel methods including screws, bioabsorbable pins, or intramedullary implants6-8.

Alternatives

Nonoperative treatments for hammer toe deformity are generally pursued prior to surgery and include shoe modifications such as a wide toe-box, soft uppers, and padding of osseous prominences3,9,10. Alternative surgical treatments include proximal interphalangeal arthroplasty, soft-tissue capsulotomy, extensor tendon lengthening, and amputation11.

Rationale

Although nonoperative treatment can alleviate symptoms temporarily, surgical treatment is often necessary for definitive treatment of hammer toe. Soft-tissue procedures such as tendon lengthening can provide a stabilizing benefit, but the degenerative bone changes associated with hammer toe are better addressed with use of resection of the proximal interphalangeal joint3. Arthroplasty allows for some retained motion; however, this motion may lead to deformity and pain over time2. Arthrodesis provides less painful and more reliable fixation as well as equal outcomes compared with other operative techniques. Patient satisfaction rates after this procedure are high, with pain relief in up to 92% of patients and rare complications7-12.

Expected Outcomes

Outcomes of this procedure are favorable, with rates of osseous fusion ranging from 83% to 98%2,4,11,13. Patient satisfaction rates range from 83% to 100%4,11. Historically, patients have expressed dissatisfaction with pain and the appearance of exposed hardware, but novel internal fixative devices provide a more natural appearance to the toe without the need for secondary surgical procedures for pin removal8,14. Patients are often able to return to regular activity at 6 weeks postoperatively; however, there may be persistent pain or swelling in the toe. Wide shoes and activity modifications are frequently continued for several more weeks postoperatively, and some patients may benefit from formal physical therapy and at-home rehabilitation.

Important Tips

Avoid vascular compromise by ensuring adequate resection of bone at the proximal interphalangeal joint.A longitudinal incision across the joint provides greater exposure but can lead to scar contracture that elevates the toe. One alternative is the use of an elliptically shaped incision over the proximal interphalangeal joint, which can improve cosmesis but does restrict exposure.Excessive osseous resection can lead to a cosmetically undesirable short toe.If using an implant for the arthrodesis, ensure the implant is not too big for the toe. Most implants are too big for fifth-toe arthrodesis.In toes with severe deformity, fixation with a Kirschner wire is often preferred because excessive stretching of the neurovascular bundle can lead to toe compromise and if Kirschner wire is used the pin can easily be removed at bedside.For flexible deformities, a nonoperative approach is recommended, such as stretching exercises, shoe-wear modifications, and metatarsal pads. A tenotomy of the flexor digitorum brevis is a soft-tissue procedure that can be considered if nonoperative treatment is insufficient to correct the deformity. If flexor digitorum brevis tenotomy does not adequately treat proximal interphalangeal joint deformity, a proximal interphalangeal joint arthrodesis should be the next step.

Acronyms and Abbreviations

MTP = metatarsophalangealPIP = proximal interphalangeal.

Current Knowledge on Biomaterials for Orthopedic Applications Modified to Reduce Bacterial Adhesive Ability

A significant challenge in orthopedics is the design of biomaterial devices that are able to perform biological functions by substituting or repairing various tissues and controlling bone repair when required. This review presents an overview of the current state of our recent research into biomaterial modifications to reduce bacterial adhesive ability, compared with previous reviews and excellent research papers, but it is not intended to be exhaustive. In particular, we investigated biomaterials for replacement, such as metallic materials (titanium and titanium alloys) and polymers (ultra-high-molecular-weight polyethylene), and biomaterials for regeneration, such as poly(ε-caprolactone) and calcium phosphates as composites. Biomaterials have been designed, developed, and characterized to define surface/bulk features; they have also been subjected to bacterial adhesion assays to verify their potential capability to counteract infections. The addition of metal ions (e.g., silver), natural antimicrobial compounds (e.g., essential oils), or antioxidant agents (e.g., vitamin E) to different biomaterials conferred strong antibacterial properties and anti-adhesive features, improving their capability to counteract prosthetic joint infections and biofilm formation, which are important issues in orthopedic surgery. The complexity of biological materials is still far from being reached by materials science through the development of sophisticated biomaterials. However, close interdisciplinary work by materials scientists, engineers, microbiologists, chemists, physicists, and orthopedic surgeons is indeed necessary to modify the structures of biomaterials in order to achieve implant integration and tissue regeneration while avoiding microbial contamination.

Flexor tenotomy for mallet toe with penetration of the middle phalanx head by dual-component intramedullary implant following proximal interphalangeal arthrodesis

Introduction

There is a risk of mallet toe following proximal interphalangeal (PIP) joint fusion for hammertoe. Here we describe a rare case of penetration of the dorsal aspect of the middle phalanx head by the distal portion of a dual-component intramedullary implant during progression of mallet toe that was treated with flexor tenotomy.

Presentation of case

A 59-year-old man underwent uneventful arthrodesis of the third PIP using a dual-component intramedullary implant and presented 6 months later with progressive mallet toe and swelling, pain, and ulceration over the distal interphalangeal joint of the third toe. Imaging showed that the distal portion of the implant had penetrated the dorsal aspect of the middle phalanx head. A longitudinal incision was made over the dorsum of the middle and proximal phalanges of the third toe and the implant was removed. A plantar incision was made at the metatarsophalangeal joint and the flexor tendon was cut to correct the mallet toe deformity. One year later, correction was satisfactory with an acceptable functional outcome and good pain relief.

Discussion

We successfully treated a man with penetration of the dorsal border of the middle phalanx head in the third toe by the distal portion of a dual-component intramedullary implant as a result of mallet toe that developed following PIP arthrodesis, by removing the implant and performing flexor tenotomy.

Conclusion

Addition of flexor tenotomy should be considered when performing PIP arthrodesis in a patient with risk factors for severe mallet toe.

•

Dual component intramedullary implant is useful for hammer toe.

•

Mallet toe occur after proximal interphalangeal arthrodesis.

•

Middle phalangeal head penetration by implant occur

•

Flexor tenotomy is useful for mallet toe.

Relative Strengths of Intramedullary K-Wire Techniques for Digital Deformities

Hammertoe deformity correction surgery is one of the most common procedures performed by foot and ankle surgeons. Recent foot and ankle medical literature presents conflicting opinions regarding the optimal intramedullary fixation device and techniques for use in digital deformity correction. There are a number of varying fixation constructs of intramedullary Kirschner wire fixation reported for proximal interphalangeal joint arthrodesis; however, there are no reports of relative loading strength of the fixations. In this study, 90 sawbone models were divided equally into 3 groups of different intramedullary Kirschner wire fixation techniques: Group A- single straight, Group B- single bent, Group C- double bent. Each fixation construct underwent controlled axial loading and failure points were observed. Results showed no significant difference in load failure from all 3 groups with mean maximum force of Group A = 20N, Group B = 19.1N, and Group C =17.5N. We conclude that all Kirschner wire fixation options for digital deformity correction, will provide similar resistance to sagittal plane axial loads.

Nitinol, Stainless Steel, and Titanium Kirschner Wire Durability

Kirschner wires (K wires) are a common fixation device in foot and ankle surgery, particularly in lesser-toe fixation. Fatigue failure is a known complication of this fixation. The material properties of the K wire are a factor in the strength and durability of the wire. The purpose of this study is to compare the durability of K wires made of stainless steel, titanium, and Nitinol. Ten samples each of stainless steel, titanium. and Nitinol underwent cyclic durability testing using a rotating beam approach, and S-N curves (applied stress vs the number of cycles to failure) were generated. The results demonstrate that, generally, Nitinol K wires have a shorter life for the same applied stress than the stainless steel or titanium wires. Titanium had a longer life at low stresses compared with stainless steel, and stainless steel had a longer life at higher stresses. This study provides comparative durability data for K wires made of different metals, which have not been previously reported. Although there was a statistically significant difference in durability for wires used in K wire fixation, all 3 metal types are reasonable choices for temporary K wire fixation.Levels of Evidence: Level 5: Mechanical study.

Ideal implant choice for proximal interphalangeal joint arthrodesis in hammer toe/claw toe deformity correction: A systematic review

Intramedullary devices have been developed to reduce the problems associated with Kirschner (K)-wire fixation in proximal interphalangeal joint (PIPJ) arthrodesis. The purpose of this systematic review is to compare the surgical outcomes of K-wires versus novel internal fixation devices in PIPJ arthrodesis in claw/hammer toe surgery. The databases searched were PubMed, Scopus, Cochrane, and Embase with keywords "claw toe OR hammer toe" AND "proximal interphalangeal OR PIP" AND "fusion OR arthrodesis." Clinical trials published in English with evidence levels I, II, and III were included. Five studies, including one randomized controlled trial and four case-controlled studies, were identified to meet the inclusion criteria. Overall, the studies showed promising results in union rates using the novel internal devices compared to K-wires. However, the novel internal devices seem not to present advantages in clinical parameters such as pain levels, patient satisfaction, foot-related function, or surgical complication rates.

[Research progress of interphalangeal arthrodesis]

OBJECTIVE

To review the research progress of interphalangeal arthrodesis in the treatment of interphalangeal joint deformity.

METHODS

The literature about interphalangeal arthrodesis at home and abroad was extensively consulted, and the indications, fusion methods, fixation methods, complications, and so on were summarized and analysed.

RESULTS

The indications of interphalangeal arthrodesis are hammer toe, claw toe, and mallet toe. From the different forms of fusion surface, fusion methods include end-to-end, peg-in-hole, conical reamer type, and V-shape arthrodesis. There are three kinds of fixation methods: Kirschner wire fixation, stainless-steel wire suture fixation, and intramedullary fixation, and there are many kinds of intramedullary fixation. The complications of interphalangeal arthrodesis include vascular injury, fixation related complications, and postoperative complications.

CONCLUSION

Interphalangeal arthrodesis is a good way to correct some deformities of toes, but the incidence of various complications can not be ignored, and there is still a lack of clinical research on interphalangeal arthrodesis.

Lesser Digit Implants

Lesser digit deformities that require surgical intervention may be corrected by interphalangeal arthrodesis. The traditional fixation device used to stabilize an interphalangeal arthrodesis is a smooth Kirschner wire (K-wire). Its use, however, has been associated with risks. The K-wires are known to migrate and break, and there are increased risks of pin tract infection. Choices for digital implants include nonresorbable, resorbable, and allograft. There are more than 60 newer intramedullary fixation devices available for use in digital surgery. Intramedullary implants also have their own inherent risks. Further research into patient outcomes and cost-effectiveness of these new devices is still needed.

Diverging Dual Intramedullary Kirschner Wire Technique for Arthrodesis of the Proximal Interphalangeal Joint in Hammertoe Correction

Digital arthrodesis is one of the most common surgical procedures performed by the foot and ankle surgeon. The market offers a variety of devices available to the surgeon to accomplish solid, permanent, and safe fusion for the patient. However, with these new devices come high surgical costs, adding to the burden on the already strapped health care system. We offer a simple technique updating the way in which a Kirschner wire is utilized for interphalangeal digital arthrodesis that employs the benefits of the newer implantable devices at a fraction of the cost. Two Kirschner wires are buried in a slightly diverging pattern to increase rotational stability while adding slight compression across the fusion site. In this article, we explain the technique and present a case example of its implementation.

LEVELS OF EVIDENCE

Therapeutic, Level V: Expert opinion.

Dual-Component Intramedullary Implant Versus Kirschner Wire for Proximal Interphalangeal Joint Fusion: A Randomized Controlled Clinical Trial

We undertook a multicenter, parallel treatment arm, randomized controlled trial to compare the outcomes after surgery for the treatment of lesser digital hammertoe using either a Kirschner wire or a 2-piece intramedullary, stainless steel implant for fixation of the proximal interphalangeal joint. Our primary aim was to compare the incidence of arthrodesis and complications, and our secondary aim was to compare the subjective foot-related outcomes measured using the Bristol Foot Score and the Foot Function Index, stratified by fixation group. We hypothesized that the use of the dual-component implant would result in greater patient satisfaction, a greater incidence of radiographic arthrodesis, and fewer complications after hammertoe repair. The overall mean age of the participants was 58.72 ± 13.48 (range 18 to 84) years, their mean body mass index was 30.14 ± 6.55 (range 20.7 to 46.98) kg/m(2), and no statistically significant differences in the demographic variables were present between the treatment groups at baseline or during the follow-up period. Of the 91 participants, 46 (50.55%) were randomly allocated to the Kirschner wire group and 45 (49.45%) to the intramedullary implant group. No statistically significant differences were observed between the 2 fixation groups in the incidence of complications; however, the 2-piece intramedullary implant group was associated with a greater mean Bristol Foot Score and Foot Function Index score and a greater incidence of fusion.

Arthrodesis of proximal inter-phalangeal joint for hammertoe: intramedullary device options

Background

Proximal inter-phalangeal (PIP) joint arthrodesis today represents the standard treatment for structured hammertoes; however, recently, a lot of new intramedullary devices for the fixation of this arthrodesis have been introduced. The purpose of this work is to look at the currently available devices and to perform a review of the present literature.

Materials and methods

A literature search of PubMed/Medline and Google Scholar databases, considering works published up until September 2014 and using the keywords: hammertoe, arthrodesis, PIP joint, fusion, intramedullary devices, and K-wire, was performed. The published papers were included in the present study only if they met the following inclusion criteria: English articles, arthrodesis of PIP joints for hammertoes with new generation intramedullary devices, series with n > 10. Studies using absorbable pins or screws that are considered as another kind of fixation that involved more than one articulation, as well as comments, letters to the editor, or newsletters were excluded.

Results

Nine publications were included. Of the patients’ reports, 93–100 % were good or excellent concerning satisfaction. Radiological arthrodesis was achieved in 60.5–100 % of cases. Three of the publications compared the new devices with the K-wire. Of these three articles, two employed the traditional technique and one the buried technique. The AOFAS score, evaluated in three publications, showed a delta of 19, 45 and 58 points. Major complications, which required a secondary surgical revision, were between 0 and 8.6 %. The complications of the K-wire and the new devices were similar; also the reoperation rate was close to equal (maximal difference 2 %). On the other hand, these kinds of devices definitely have a higher price, compared to the K-wire.

Conclusion

The use of these new devices provides good results; however, their high price is currently a problem. For this reason, cost-benefit studies seem to be necessary to justify their use as standard treatment.

Level of evidence

Level III systematic review.

Hammertoe correction with k-wire fixation

BACKGROUND

Kirschner wire (K-wire) fixation for correction of hammertoe deformity is a common, low-cost method for fixation of hammertoes after proximal interphalangeal (PIP) arthroplasty or fusion. Complications of this procedure include pin-tract infection, pin migration, pin bending or breakage, and recurrence of deformity. The investigators reviewed a large experience using K-wire stabilization for hammertoe correction.

METHODS

All hammertoe corrections performed by a single surgeon from 1999 to 2013 were retrospectively reviewed. A resection arthroplasty of the PIP joint or PIP fusion was performed and fixed with a K-wire. Follow-up duration, preoperative diagnosis, pin duration, concomitant procedures, recurrence rates, and complications were reviewed and analyzed. A total of 1,115 operations were performed on 876 patients, with correction of 2,698 hammertoes. There were 709 female and 167 male patients, with an average age of 57.5 years (range, 14-88 years), followed for an average of 20.8 months (range, 27 days to 12.7 years).

RESULTS

Complications included 94 pin migrations (3.5%), 9 pin-tract infections (0.3%), and 2 pin breakages (0.1%). There were 150 recurrent deformities (5.6%) and 94 toes (3.5%) required revision hammertoe surgery. Malalignment was noted in 55 toes (2.1%). Vascular compromise occurred in 16 toes (0.6%), with 10 (0.4%) requiring amputation. Ninety-four toes (3.5%) required revision surgery because of symptomatic recurrence of deformity. The expected rates and rate ratios (RRs) of patients requiring revision hammertoe correction, compared with the study population as a whole, were statistically significantly higher in patients who underwent an metatarsophalangeal joint capsulotomy (3.10 vs 0.97; RR, 3.20) and those who experienced K-wire-related complications (5.10 vs 1.80, RR, 2.84).

CONCLUSIONS

K-wire fixation for the treatment of hammertoe deformities led to good maintenance of correction with a relatively low complication rate, and we believe that it remains an effective, low-cost method of fixation for hammertoe correction.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Prospective study of hammertoe correction with an intramedullary implant

BACKGROUND

Operative correction of a hammertoe deformity is often accomplished by excision of the articular surface of the proximal interphalangeal joint (PIP) and fixation across the joint. This study aimed to prospectively evaluate clinical and radiographic outcomes of hammertoe operative correction utilizing an internal implant and assess its ability to maintain postoperative alignment.

METHODS

Twenty-nine patients (53 toes) with a painful rigid hammertoe deformity were prospectively enrolled and operatively treated with resection arthroplasty of the PIP joint and fixation with an implant. Five patients were lost to follow-up, and 24 patients (42 toes) returned at an average of 12 months for final clinical and radiographic evaluation. All patients were evaluated pre- and postoperatively by AOFAS and Visual Analog Pain Scale (VAS) scores. On physical exam, the location and magnitude of the deformity, callosities, and digit circumference were recorded. Radiological parameters evaluated were digital alignment, successful union, implant position, and bone reaction.

RESULTS

All patients reported satisfaction at final follow-up, with an average improvement of AOFAS score from 52 (range, 24-87 points) to 71 (range, 42-95 points) points. The mean VAS pain score improved from 5 points (range, 2 to 10) preoperatively to 1 point (range, 0 to 5) postoperatively. Of patients, 87% reported an ability to return to their preoperative activities without limitations. Regarding digital alignment, there were no recurrent deformities or transverse plane deformities; 1 toe presented with a minor digital rotational deformity at final follow-up. Postoperative radiographs indicated 100% of proximal interphalangeal (PIP) joints with good alignment, and 81% demonstrated bony union.

CONCLUSION

Our results suggest that utilization of an internal implant for hammertoe correction was safe and provided acceptable alignment, pain reduction, and improved function at final follow-up.

LEVEL OF EVIDENCE

Level IV, case series.