Plantar versus dorsomedial locked plating for Lapidus arthrodesis: a biomechanical comparison

Biomechanical Evaluation of Fourth Generation Minimally Invasive Distal First Metatarsal Osteotomy-Akin Osteotomy Technique on First Ray Articular Contact Properties

BACKGROUND

Hallux valgus is a common deformity encountered but remains a complex clinical entity. Fourth-generation minimally invasive surgery (MIS) techniques consisting of a percutaneous distal metatarsal transverse osteotomy combined with an Akin osteotomy have been used to address mild to severe hallux valgus deformities. The benefits of an MIS approach include improved cosmesis, faster recovery, lower opiate requirement, immediate weightbearing, and favorable outcomes relative to a traditional, open procedure. An understudied area with respect to hallux valgus correction is the effect that osteotomies can have on the articular contact properties of the first ray following correction.

METHODS

Sixteen paired cadaveric specimens were dissected to include the first ray and tested in a customized apparatus. Specimens were randomized to receive a distal transverse osteotomy translated either 50% or 100% of the width of the first metatarsal shaft. The osteotomy was performed with either a 0° or 20° distal angulation of the burr relative to the shaft in the axial plane. Specimens were tested in the intact state and following the distal first metatarsal osteotomy for peak pressure, contact area, contact force and center of pressure at the first metatarsophalangeal (MTP) and first tarsometatarsal (TMT) joints. An Akin osteotomy was then performed on each specimen, and peak pressure, contact area, contact force, and center of pressure were recalculated.

RESULTS

There was a notable decrease in peak pressure, contact area, and contact force across the TMT joint with greater shifts of the capital fragment. However, at 100% translation of the capital fragment, distal angulation of the osteotomy by 20° appears to improve loading across the TMT joint. Addition of the Akin osteotomy at 100% translation also aids in increasing the contact force across the TMT joint. The MTP joint is less sensitive to changes in shifts and angulation of the capital fragment. The Akin osteotomy also leads to increased contact force across the MTP joint when the capital fragment is translated 100%.

CONCLUSION

While the clinical significance is unknown, larger shifts of the capital fragment lead to greater load alterations at the level of the TMT joint than the MTP joint. Distal angulation of the capital fragment and the addition of an Akin osteotomy can aid in reducing the size of those changes. The Akin can lead to increased contact forces at the MTP joint with 100% translation of the capital fragment.

LEVEL OF EVIDENCE

Not applicable, Biomechanical study.

First cuneo-metatarsal arthrodesis (Modified Lapidus) with plantar plate for the treatment of hallux valgus: clinical and radiological outcomes at one year follow-up

INTRODUCTION

The modified Lapidus arthrodesis, involving the first cuneo-metatarsal joint, is a well-established surgical method and widely utilized for treating moderate to severe hallux valgus deformities with hypermobility in the first tarsometatarsal joint. The purpose of this study was to assess the rate of union following the Lapidus procedure using a plantar plate and an immediate full weight-bearing protocol. Secondary objectives included examining radiological corrections and potential associated complications.

METHODS

A retrospective study included 66 patients (80 feet) who underwent a modified Lapidus procedure for the treatment of hallux valgus associated with hypermobility of the first ray, performed by a single senior surgeon at our institution between May 2013 and November 2019. All patients had a minimum follow-up of 12 months. Patients were clinically assessed at 3 weeks, 3 months, and 1 year. Radiological measurements were taken on weight-bearing dorsoplantar views preoperatively, at 3 months, and at 12 months postoperatively.

RESULTS

Bone union was achieved in 79 cases (98.75%). There was one case of non-union, two wound complications (one infection and one dehiscence), two cases of symptomatic hardware requiring hardware removal, and one stress fracture associated with recurrence of hallux valgus that required revision. The mean hallux valgus angle (HVA) improved from 30.5 ° ±10.4 ° to 10.1 ° ±6.6 ° (p < .001), the mean intermetatarsal angle (IMA) improved from 13.4 ° ±3.6 ° to 5.6 ° ±2.9 (p < .001), The average sesamoid position improved from stage 5.9 ± 1.6 to stage 2.6 ± 1.2 (p < .001). The mean shortening of the first metatarsal was 3.6 mm ± 1.8. There was no significant difference between measurements at 3 and 12 months postoperatively.

CONCLUSION

Modified Lapidus with a planter plate and compression screw is a reliable method of fixation with a high union rate, permit an immediate protected weight bearing and a low complications rate.

LEVEL OF EVIDENCE

IV; Retrospective study.

First tarsometatarsal arthrodesis for severe hallux valgus using the tension band principle - Technical tip and case series

BACKGROUND

Hallux valgus (HV) is a common foot pathology. Severe HV in the presence of Tarsometatarsal joint (TMTJ) instability is often managed with arthrodesis of the 1st TMTJ. There are concerns regarding non-union and malunion (particularly the early loss of inter-metatarsal angle correction before complete arthrodesis). We report our medium-term results of a small series of patients that underwent an evolved surgical technique utilising orthogonal staples and a transverse suture button fixation to address biomechanical concerns with traditional Lapidus arthrodesis.

METHODS

A retrospective study of a consecutive series of patients who underwent this surgical technique between February 2017 and May 2022. Clinical outcomes were validated through Patient-reported outcomes measures (PROMS); EuroQol-5 Dimension (EQ-5D) and Manchester-Oxford Foot Questionnaires (MOXFQ). Radiographic parameters (hallux valgus (HVA), intermetatarsal (IMA), distal metatarsal articular angle (DMAA)) were assessed. Union of the arthrodesis and complications were recorded.

RESULTS

During the study period, 9 feet underwent the procedure. Radiographic data was available for all nine and PROMS data for seven (77.8%). Significant improvement occurred in all radiographic deformity parameters at mean 6-month follow-up. Mean ± standard deviation correction calculated preoperatively as HVA 40.2°, IMA 19.3° and DMAA 15.8°, corrected to HVA 15.4°, IMA 5.8° and DMAA 5.9° postoperatively. (HVA; P < 0.001, IMA; P < 0.001, DMAA; P < 0.001) Clinical PROMs at mean follow-up of 2 years were MOXFQ 34.4 ± 25.2, EQ-5D-5 L 0.819 ± 0.150 and VAS pain 13.6 ± 13.6. There were no cases of non-union, Tibialis anterior tendon irritation or hallux varus. Complications included first MTPJ stiffness in one case and CRPS and dorsiflexion malunion of the first ray in another patient.

CONCLUSION

This preliminary study of the procedure used in this series confirm this is a safe surgical technique to address severe HV with a low rate of non-union and significant radiographic improvements. A larger patient dataset is needed to evaluate this procedure robustly.

Early Functional Rehabilitation in Foot and Ankle Surgery

The traditional postoperative management of common foot and ankle procedures has involved a prolonged period of immobilization and nonweight bearing. The concern was loss of correction and fixation failure. However, it has been shown that a prolonged period of nonweight bearing can predispose patients possible deep vein thrombosis, disuse osteopenia, cardiovascular complications, and generalized deconditioning. The authors' institution has published studies reviewing the efficacy of early weight bearing after first metatarsophalangeal joint arthrodesis, modified Lapidus bunionectomy, and open reduction and internal fixation of ankle fractures. This article highlights the literature and rationale supporting the safety of early weight-bearing protocols.

Open vs Minimally Invasive Resection of the First Metatarsocuneiform Joint: An Anatomical Study

BACKGROUND

The modified Lapidus arthrodesis is a standard procedure to correct middle to severe hallux valgus (HV) deformities. Recently, minimally invasive techniques of first metatarsocuneiform joint (MCJ) resection using a Shannon burr were described. The primary goal of this study is to compare the anatomical efficacy and safety of first MCJ resection using a straight 2 × 13-mm Shannon burr and minimally invasive technique (MIS) vs an open technique using an oscillating saw.

METHODS

Ten pairs of fresh frozen cadaveric feet were randomly assigned to open or MIS first MCJ resection with subsequent systematic dissection. For the MIS procedure, a dorsomedial approach was used and for the open procedure a medioplantar approach was used. Cartilage removal was investigated by analyzing standardized scaled photographs of the resected articular surfaces with ImageJ software. Nearby structures at risk were analyzed for iatrogenic violation: tibialis anterior (TA), extensor hallucis longus (EHL) and peroneus longus (PL) tendons, and the Lisfranc ligament complex (LLC).

RESULTS

In the MIS group, the median cartilage resection was 85.9% at the cuneiform and 85.6% at the metatarsal bone compared to 100% cartilage resection in open technique (P < .01). Iatrogenic damage of the LLC, EHL, and TA tendons was not found in any group. The PL tendon was thinned out (<25% of tendon thickness) in 4 cases (40%) in the open group and in 1 case (10%) in the MIS group. A safe zone of 3.0 mm between the articular surface of the cuneiform bone and the LLC was identified, which can be resected without putting the LLC at risk when performing lateral-based wedge resections.

CONCLUSION

In this cadaver study with the procedures performed by an experienced foot and ankle surgeon, and using 2 different surgical approaches, we found general parity between the Shannon burr MIS technique vs oscillating saw open technique techniques with more risk to the PL with our open technique and approximately 15% less cartilage resection with our MIS technique.

LEVEL OF EVIDENCE

Level V, cadaver study.

Indications and possible limitations using medio-plantar plate systems in tarsometatarsal 1 fusions - A cadaveric study

BACKGROUND

The tarsometatarsal 1 arthrodesis is an adequate treatment for moderate to severe hallux valgus deformity and instability of the first ray. Plantar plating arthrodesis has been shown to provide better mechanical stability and fewer postoperative complications than screw fixation or medial plating. The medio-plantar plate is a new plate design for Lapidus arthrodesis. It could combine the biomechanical advantages of the plantar plate and the anatomical overview of a medial plate. However, the implanted material can cause irritation of the tibialis anterior, which in some cases may require removal of the material. The purpose of this study was to examine the possibility of tendon irritation following medio-plantar first tarsometatarsal joint arthrodesis using cadaveric specimens.

METHODS

The study involved the simulated surgical procedure of medio-plantar plate arthrodesis on 30 lower extremities. After the plates were fixed, a thorough examination of the feet was conducted to assess any tendon irritation and to determine a recommendation for placement of the medio-plantar plate based on the Olewnik classification.

RESULTS

Irritation of the tibialis anterior tendon components with the medio-plantar plate depends mainly on the anatomic norm variant, classified according to Olewnik et al. A medio-plantar plate is particularly recommended in TA tendon Olewnik type 3 and type 5. The positioning of a medio-plantar plate in Olewnik type 1 and type 2 tendons depends on the anatomic fit of the medio-plantar plate and the bony configuration of the TMT 1 joint. A large portion of the TA tendon must be detached, so a different plate design may be preferred in these patients.

CONCLUSIONS

TMT 1 arthrodesis with medio-plantar plating of the first tarsometatarsal joint should be performed considering the anatomic TA tendon variations.

LEVEL OF EVIDENCE

Level V, Expert Opinion includes Case Reports and Technique Tips.

Biomechanical Comparison of Medio-Plantar and Plantar Plate Fixation for First Tarsometatarsal Joint Arthrodesis

Plantar plate positioning has been demonstrated as biomechanically superior. However, some operators remain resentful about the morbidity of the surgical approach. To provide improved plate fixation for first tarsometatarsal joint arthrodesis with respect to the tibialis anterior tendon, a medio-plantar plate was developed. The purpose of this biomechanical study was to compare its construct stability to that of a plantar plate construct. Twelve pairs of fresh frozen human specimens were used in a matched pair test. Each pair was fixed with a 4 mm compression screw and either a plantar locking plate or a medio-plantar locking plate. A cantilever beam test was performed in dorsiflexion. Before and after cyclic loading (5000 cycles; 40 N), bending stiffness and relative movements at the joint space were monitored in a quasi-static test including optical motion tracking. Maximum load and bending moment to failure were investigated in a load-to-failure ramp test. The bending stiffness of both groups did not significantly differ before (plantar 49.9 N/mm ± 19.2; medio-plantar 53.9 N/mm ± 25.4, p = 0.43) or after (plantar 24.4 N/mm ± 9.7; medio-plantar 35.3 N/mm ± 22.0, p = 0.08) cyclic loading but decreased significantly in both groups (p < 0.01) after cyclic loading. Relative movement increased significantly during cyclic testing in both groups (p < 0.01) but did not differ significantly between the groups before (p = 0.29) or after (p = 0.16) cyclic loading. Neither load nor bending moment to failure were significantly different (plantar 225 N ± 78, 10.8 Nm; medio-plantar 210 N ± 86, 10.1 Nm, p = 0.61). Both plate constructs provided equivalent construct stability, both being well suited for Lapidus arthrodesis.

Union Rates With the Use of Structural Allograft in Lapidus Arthrodesis: A Comparison Between Two Fixation Constructs

Although structural allograft has been previously described as acceptable practice for reconstructive foot and ankle surgery, results for an allograft bone wedge in Lapidus arthrodesis are unknown. Additionally, there is no consensus on the superiority of a single fixation construct in Lapidus cases. Our objective was (1) to report union rates for Lapidus arthrodesis with and without the use of an allograft bone wedge and (2) to determine if fixation construct impacts rates of union when using structural allograft. A review was performed for Lapidus cases with fixation constructs of 2 crossed compression screws (CS) and a medial locking plate with single transarticular screw (MPS), both with and without use of an allograft bone wedge. Inclusion required a CT scan to evaluate bony union. There was no significant difference in union rates (p = .41) between the use (90%) and the nonuse (97%) of an allograft bone wedge. Union rates were significantly different (p = .04) when comparing CS fixation (85%) and MPS fixation (98%). The comparative results between the fixation constructs highlight the importance of compression across the arthrodesis site as part of a robust fixation construct. Our findings demonstrate that the use of an allograft bone wedge in Lapidus arthrodesis may mitigate complications due to metatarsal shortening while providing satisfactory rates of union.

Plantar Plating in the Modified Lapidus Procedure: Evaluation of Function and Impairment of the Tibialis Anterior Tendon

The modified "Lapidus" procedure (MLP) describes the arthrodesis of the first tarsometatarsal joint. We investigate if there are detectable changes of the tendon or the function of the muscle and clinical outcome after MLP. We reviewed 22 feet. All patients underwent magnetic resonance imaging (MRI) at an average of 27 (range, 12-49) months. Clinical outcome was evaluated using the European Foot and Ankle Society score. Strength was measured and complications were assessed. MRI revealed signs of tendinopathy of the tibialis anterior tendon in 13 feet (59%). The mean total European Foot and Ankle Society score at final follow-up was 17 (range, 6-24) points. The mean postoperative Visual Analog Scale score was 1.4 (range, 0-5). Range of motion and force data were not significantly different to the contralateral side. In conclusion, MRI showed signs of tendinopathy in 59%, which does not seem to affect clinical outcome, but has to be considered when choosing the desired implant and placement. MLP leads to high patient satisfaction rates and significant improvement at midterm follow up.

Biomechanical evaluation of the proximal chevron osteotomy in comparison to the Lapidus arthrodesis for the correction of hallux valgus deformities

PURPOSE

The proximal chevron osteotomy and the modified Lapidus arthrodesis are both procedures utilized for deformity correction in patients with severe symptomatic hallux valgus. The aim of the current study was to compare their biomechanical stability when using locking plate fixation.

METHODS

Twelve matched pairs of human anatomical lower leg specimens underwent on one side a proximal chevron osteotomy with a medial locking plate and on the other side a modified Lapidus arthrodesis with a plantar locking plate utilizing an interfragmentary compression screw. All specimens underwent bone mineral density (BMD) assessment and were tested in a servohydraulic load frame which applied a load on the centre of the metatarsal head over 1000 loading cycles with subsequently ultimate load testing. Displacement of the proximal and distal bone segment, ultimate load, and bending stiffness were analyzed.

RESULTS

Mean displacement of both procedures showed no statistically significant difference throughout all the loading cycles (0.213 ≤ p ≤ 0.834). The mean ultimate load of the proximal chevron osteotomy was 227.9 N (± 232.4) and of the modified Lapidus arthrodesis 162.9 N (± 74.6) (p = 0.754). The proximal chevron osteotomy (38.2 N/mm (± 24.9)) had a significantly higher bending stiffness compared to the modified Lapidus arthrodesis (17.3 N/mm (± 9.9)) (p = 0.009). There was no correlation between BMD and displacement in all loading cycles, ultimate load, and bending stiffness of either procedure (p > 0.05).

CONCLUSION

Although the bending stiffness of the chevron osteotomy was higher, there was no statistically significant difference between the surgical techniques in mean displacement and ultimate load. The BMD did not influence the overall stability of either reconstruction. Locking plate fixation increases the clinical value of the modified Lapidus arthrodesis by outweighing most of the biomechanical disadvantages in comparison to the proximal chevron osteotomy.

Early Results and Patient-Reported Outcome Measures (PROMS) of an Intraosseous Device for Arthrodesis of the First Tarso-Metatarsal (TMT) Joint

BACKGROUND

We describe a new surgical technique for arthrodesis of the first tarso-metatarsal (TMT) joint using an intraosseous fixation device and the early results including patient-reported outcome measures (PROMS).

MATERIALS AND METHODS

Seventeen consecutive procedures with this method were included. Indication for surgery was hallux valgus. The average age was 42 years (range 26-65). PROMS were collected and the patients were asked to fill out a satisfaction questionnaire. A retrospective review of radiographs and electronic medical notes was conducted.

RESULTS

Overall fusion rate was 94%. Complications included a case of failed fusion, a superficial wound infection and a deep vein thrombosis (DVT). At a mean follow-up of 24 months (range 10-38) radiographic results demonstrated significant improvement in the intermetatarsal angle or IMA (11.7 ± 2.8 degrees to 6.9 ± 2.4 degrees, P < 0.001) and hallux valgus angle or HVA (28.1 ± 7.3 degrees to 12.2 ± 4.3 degrees, P < 0.001). The mean visual analog scale (VAS) score improved significantly from a mean of 7.6 (SD 0.85) preoperatively, to a mean of 2.1 (SD 1.83) post-operatively (P < 0.0001). The Manchester-Oxford Foot Questionnaire (MOXFQ) significantly improved from a mean of 35.8 (SD 10.2), to a mean of 9.2 (SD 17) (P < 0.0001). The final result was satisfactory for 88% of the patients.

CONCLUSIONS

The early results show intraosseous fixation to be a safe and efficient method for the fusion of the first TMT joint providing good patient satisfaction.

Biomechanical Evaluation of Tarsometatarsal Fusion Comparing Crossing Lag Screws and Lag Screw With Locking Plate

BACKGROUND

Tarsometatarsal (TMT) arthrodesis is a common operative procedure for end-stage arthritis of the TMT joints. To date, there is no consensus on the best fixation technique for TMT arthrodesis and which joints should be included.

METHODS

Thirty fresh-frozen feet were divided into one group (15 feet) in which TMT joints I-III were fused with a lag screw and locking plate and a second group (15 feet) in which TMT joints I-III were fused with 2 crossing lag screws. The arthrodesis was performed stepwise with evaluation of mobility between the metatarsal and cuneiform bones after every application or removal of a lag screw or locking plate.

RESULTS

Isolated lag-screw arthrodesis of the TMT I-III joints led to significantly increased stability in every joint (P < .05). Additional application of a locking plate caused further stability in every TMT joint (P < .05). An additional crossed lag screw did not significantly increase rigidity of the TMT II and III joints (P > .05). An IM screw did not influence the stability of the fused TMT joints. For TMT III arthrodesis, lag-screw and locking plate constructs were superior to crossed lag-screw fixation (P < .05). TMT I fusion does not support stability after TMT II and III arthrodesis.

CONCLUSION

Each fixation technique provided sufficient stabilization of the TMT joints. Use of a lag screw plus locking plate might be superior to crossed screw fixation. An additional TMT I and/or III arthrodesis did not increase stability of an isolated TMT II arthrodesis.

CLINICAL RELEVANCE

We report the first biomechanical evaluation of TMT I-III arthrodesis. Our results may help surgeons to choose among osteosynthesis techniques and which joints to include in performing arthrodesis of TMT I-III joints.

Biomechanical evaluation of naviculocuneiform fixation with lag screw and locking plates

BACKGROUND

There have been no biomechanical evaluations of naviculocuneiform (NC) joint fixation. This study compared biomechanically 3 different fixation constructs for NC-1-3 joint fixation.

METHODS

The present study compared the three fixation constructs lag screw with locking plate for each NC joint, two crossed lag screws for each NC joint and a separate lag screw for each NC joint with bridging locking plates. NC-1-3 fixation was performed stepwise, and rotation of each joint was evaluated after the application of each lag screw or locking plate and their removal.

RESULTS

All examined fixation techniques led to a significant reduced rotation of the NC joints. For NC-1 rotation decreased from 2.8° (Range 1.2-6.6°) to 0.6° (0.2-3.0°) for lag screw and locking plate (p = 0.002) and from 5.0° (1.7-9.8°) to 1.0° (0.1-3.6°) for crossed lag screws (p = 0.002). For NC-2, locking plate constructs were better with 0.2° (0.1-0.5°) compared to crossed lag screw osteosynthesis with 0.9° (0.2-1.6°) (p = 0.011).

CONCLUSION

Each evaluated fixation technique led to a reduced NC joint rotation. The fixation of any NC joint had no relevant effect on the adjacent NC joints. The results might support surgeons treating NC joint disorders.

Anatomical reconstruction of first ray instability hallux valgus with a medial anatomical TMTJ1 plate

BACKGROUND

First tarsometatarsal joint (TMTJ1) arthrodesis is a powerful tool for hallux valgus correction. Past criticism of the TMTJ1 arthrodesis has focused on high non-union rates, and consequent need for delayed weightbearing as prevention. In this study we present a selection and treatment protocol to minimise non-union while allowing early weightbearing.

METHODS

All TMTJ1 arthrodesis procedures for hallux valgus performed by the senior surgeon over the period June, 2016 to July, 2019 were included. An anatomically-designed, medial TMTJ1 plate and screw compression was utilised for TMTJ1 arthrodesis. The construct was augmented with synthetic intermetatarsal stabilisation. All patients were kept non-weightbearing for 2 weeks, followed by progressive weightbearing as tolerated for 4 weeks. Minimum follow-up was 1 year.

RESULTS

300 modified Lapidus procedures were performed for hallux valgus with mean IMA 17° (Range: 14-29). Mean age was 58 years, with 93% female. 284 (94%) had an Akin osteotomy, while 222 cases (74%) were associated with another forefoot procedure. Patients began progressive weight bearing as tolerated from 2 weeks. All were fully weight bearing by 8 weeks post-operatively. There was a 100% union rate in this group. Mean AOFAS Hallux MTP-IP scores rose from 59 pre-operatively to 97 post-operatively. One plate was removed due to tibialis anterior impingement. There were no recurrences at final follow-up.

CONCLUSIONS

We describe a selection and treatment protocol for TMTJ1 arthrodesis for hallux valgus. This yields high union rates while allowing early weight bearing.

LEVEL OF EVIDENCE

4.

Effectiveness of the Lapidus plate system in foot surgery: A PRISMA compliant systematic review

Lapidus arthrodesis is an established standard procedure to correct various foot surgery problems and hallux limitus, hypermobility of the first ray, hallux abductus valgus, and symptomatic lesser metatarsal. After decades, many fixation methods in the orthopaedic surgery industry have been developed for decreasing complications and improving this technique. The aim of this PRISMA compliant systematic review is to analyse the effectiveness of several lapidus plate systems in foot surgery. We have carried out the first systematic review of the relevant published literature so as to systematically evaluate the scientific knowledge available now on this association, assigning predefined eligibility criteria. Fourteen studies were selected which had an overall of 738 cases. The first tarsal metatarsal joint and hallux valgus were treated by the application of different types of Lapidus plate system. The optimal level of the fixation in these procedures is related with the type and system insertion place of the plate with or without screw in each specific foot disease. There is an insufficient number of studies about the effectiveness of the different types of Lapidus plate system in foot surgery, and there is a need to increase outcomes knowledge on the level of the fixation, sort of the system, and insert place in foot surgery.

Radiographic Outcomes, Union Rates, and Complications Associated With Plantar Implant Positioning for Midfoot Arthrodesis

Background:

Midfoot arthrodesis has long been successfully included in the treatment paradigm for a variety of pathologic foot conditions. A concern with midfoot arthrodesis is the rate of nonunion, which historically has been reported between 5% and 10%. Plantar plating has also been noted to be more biomechanically stable when compared to traditional dorsal plating in previous studies. Practical advantages of plantar plating include less dorsal skin irritation and the ability to correct flatfoot deformity from the same medial incision. The purpose of this study is to report the arthrodesis rate, the success of deformity correction, and the complications associated with plantar-based implant placement for arthrodesis of the medial column.

Methods:

A retrospective review was undertaken of all consecutive patients between 2012 and 2019 that underwent midfoot arthrodesis with plantar-positioned implants. Radiographic outcomes and complications are reported on 62 patients who underwent midfoot arthrodesis as part of a correction for hallux valgus deformity, flatfoot deformity, degenerative arthritis, Lisfranc injury, or Charcot neuroarthropathy correction.

Results:

Statistically significant improvement was seen in the lateral talus–first metatarsal angle (Meary angle) and medial arch sag angle for patients treated for flatfoot deformity correction. In patients treated for hallux valgus deformity, there was a reduction in the intermetatarsal angle from 15.4 to 6.8 degrees. The overall nonunion rate was 6.45% in all patients. The rate of nonunion was higher at the NC joint compared to the TMT joint and with compression claw plates. One symptomatic nonunion required revision surgery (1.7%). There were no nonunions when excluding neuroarthropathy patients and smokers. The odds ratio (OR) for nonunion in patients with neuroarthropathy was 6.05 ( P < .05), and in active smokers the OR was 2.33 ( P < .05).

Conclusion:

Plates placed on the plantar bone surface for midfoot arthrodesis achieved and maintained deformity correction with rare instances of symptomatic hardware for a variety of orthopedic conditions. An overall clinical and radiographic union rate of 94% was achieved. The radiographic union rate improved to 100% when excluding both neuroarthropathy patients and smokers. The incidence of nonunion was higher in smokers, neuroarthropathy patients, naviculocuneiform joint fusions, use of compression claw plates, and when attempting to fuse multiple joints. Incisional healing complications were rarely seen other than in active smokers.

Level of Evidence:

Level IV, case series.

Early Results of Immediate Weightbearing Following First Tarsometatarsal Joint Arthrodesis With Plantar Locking Plate and Dorsal Compression Screw

Arthrodesis of the first tarsometatarsal joint (TMT1) reduces pathologic angles at the anatomic center of rotation of angulation and presents a substantial correction potential in 3 planes in the treatment of hallux abductovalgus. The optimal fixation method remains unclear since prevailing dorsomedial locking plates and/or compression screws depict elevated implant-associated complications. Medical records of 49 patients that underwent 53 TMT1 arthrodeses in hallux abductovalgus interventions were included. Median average visual analog scale scores decreased (p < .001) from 6.8 (range 4-10) to 2.7 (range 0-10), first intermetatarsal angles were reduced (p < .001) from 17.39° (range 12°-28°) to 7.16° (range 3°-12°), standing lateral first metatarsal angles improved (p < .001) from 21.66° (range 12°-29°) to 23.94° (range 14°-31°) and tibial sesamoid positions were plantarized (p < .001) from 6.02° (range 4°-7°) to 2.79° (range 1°-6°). Plantar plating allowed immediate weightbearing with transition to normal shoe gear at 6 weeks. Complications occurred in 6 (11.34%) feet including 1 (1.89%) nonunion, 1 (1.89%) delayed union, 1 (1.89%) hallux varus, 1 (1.89%) incomplete recurrence, 1 (1.89%) minor dehiscence, and 1 (1.89%) hardware irritation. Plantar locking plates combined with a dorsal compression screw presented a favorable tension-side implant location that closed the fusion site under load. This facilitated substantial reductions in complications, pathologic angles, and pain.

The Lapidus Arthrodesis: Examining the Effect of the Metatarsal Base Transfixion Screw

The modified Lapidus bunionectomy is a useful and highly powerful procedure for correcting hallux abducto valgus. Traditionally reserved for "severe" deformities, this procedure has seen a recent resurgence in the podiatric community for its unique ability to achieve tri-planar correction of this challenging deformity. Although this procedure has been extensively studied in both biomechanical labs and the clinical arenas, no clear consensus has been achieved regarding optimal fixation for this thought-provoking procedure. The current study examined the differences in strength between commercially available 5-hole locking plates with interfragmentary compression vs a crossed-screw with a third "transfixation" screw construct in a controlled setting. Ten fresh-frozen cadaveric match pair limbs (20 total limbs) were used to complete this study. Ten limbs were randomly assigned to a 3-screw construct. The other 10 contralateral limbs were assigned to a commercially available 5-hole locking plate (5 stainless steel and 5 titanium alloy) with an interfragmentary lag screw construct. The first rays were then isolated and potted into a 4-point bending device. The specimens were loaded to failure in a servohydraulic load frame at a controlled rate. Failure was defined as catastrophic or 3 mm of plantar gapping at the arthrodesis site. The mean maximal load to failure was 310.9 ± 109.4 N for the 3-screw construct. The mean maximal load to failure for the locking plate constructs was 264.1 ± 100.9 N. This difference was not statistically significant (p = .328). These results suggest that a 3-screw construct for Lapidus arthrodesis is as strong as commercially available locking plate constructs.

Comparison of Isolated Screw to Plate and Screw Fixation for Tarsometatarsal Arthrodesis Including Clinical Outcome Predictors

BACKGROUND

The common treatment for end-stage tarsometatarsal (TMT) arthritis is an arthrodesis of the affected joints. This study was performed to examine the clinical and radiographic outcome after TMT arthrodesis and to identify risk factors for postoperative complications.

METHODS

A total of 101 patients with tarsometatarsal arthritis of at least 2 joints were retrospectively examined. Data were acquired using clinical and radiographic examination, pedobarographic analysis, and standardized questionnaires, including the European Foot and Ankle Society Score, the Foot and Ankle Outcome Score, a pain numeric rating scale (NRS), the 36-Item Short Form Health Survey, and the University of California at Los Angeles Activity (UCLA) Score. The fixation technique, any complications, and revision surgery were recorded.

RESULTS

All scores improved significantly, except for the UCLA Score. The mean pain NRS score was significantly reduced from 7.7 preoperative to 3.0 postoperative (P < .05). The overall nonunion rate was 12.6%. Compared with 2 crossed-screw fixation, locking plate plus compression screw fixation was associated with a decreased nonunion rate (odds ratio [OR] 0.165, 95% confidence interval [CI] 0.032-0.854; P = .017). A body mass index >27 was significantly associated with a higher nonunion rate and wound healing problems (OR 12.05, 95% CI 1.430-101.468; P = .006; OR 5.03, 95% CI 1.273-19.871; P = .013). The overall reoperation rate was 25.2%.

CONCLUSION

TMT arthrodesis of the medial and central column resulted in significant improvement in foot function and pain. A major complication was nonunion. Locking plate plus compression screw fixation was associated with a lower nonunion rate.

LEVEL OF EVIDENCE

Level III, comparative series.

Revision of Malaligned Lapidus and Nonunited Lapidus

"Lapidus arthrodesis is becoming more of a common procedure for treatment of hallux valgus deformities. Like other procedures, complications are possible. The common complications associated with Lapidus arthrodesis procedures include nonunion and malunion. Malunion is typically broken down into recurrence, elevated first ray, shortened first ray, or plantarflexed first ray. This article discusses these common complications after Lapidus arthrodesis.

Anatomical study of Lapidus arthrodesis using two different plantar plate systems

BACKGROUND

First tarsometatarsal arthrodesis (modified Lapidus procedure) constitutes a sufficient treatment for moderate to severe hallux valgus deformity and first ray instability. The plantar plate arthrodesis was shown to provide superior mechanical stability and less postoperative complications than screw fixation or dorsal plating. Nevertheless, the in-brought hardware may cause irritation of the tibialis anterior or peroneus longus tendon requiring explantation of the material in some cases. The purpose of this study was to investigate the potential of tendon irritation after plantar first tarsometatarsal joint arthrodesis in a cadaver study.

METHODS

Plantar plate arthrodesis was performed as in real surgery on twelve pairs of fresh frozen cadaveric feet. Two different plate systems were randomly allocated to each pair of feet. After plate fixation careful dissection of the feet followed to analyze potential tendon irritation and to determine a "safe zone" for plantar plate placement.

RESULTS

A "safe zone" between the insertion sties of tibialis anterior and peroneus longus tendon was found and proven to be sufficiently exposed using a standard medio-plantar approach. Both plates were fixed in this zone without compromising central tendon parts. Peripheral tendon parts were irritated in 42% using Darco Plantar Lapidus Plating System® (Wright Medical, Memphis, TN) and in 8% using the Plantar Lapidus Plate® (Arthrex, Naples, FL). Bending of the anatomically preshaped plates is often necessary to ensure optimal fit on the bone surface.

CONCLUSIONS

Modified Lapidus procedure with plantar plating of the first tarsometatarsal joint can be performed safely without compromising central tendon parts via standard medio-plantar approach.

LEVEL OF CLINICAL EVIDENCE

5, Cadaver Study.

Lisfranc fracture-dislocations: current management

It is essential to know and understand the anatomy of the tarsometatarsal (TMT) joint (Lisfranc joint) to achieve a correct diagnosis and proper treatment of the injuries that occur at that level.

Up to 20% of Lisfranc fracture-dislocations go unnoticed or are diagnosed late, especially low-energy injuries or purely ligamentous injuries. Severe sequelae such as post-traumatic osteoarthritis and foot deformities can create serious disability.

We must be attentive to the clinical and radiological signs of an injury to the Lisfranc joint and expand the study with weight-bearing radiographs or computed tomography (CT) scans.

Only in stable lesions and in those without displacement is conservative treatment indicated, along with immobilisation and initial avoidance of weight-bearing.

Through surgical treatment we seek to achieve two objectives: optimal anatomical reduction, a factor that directly influences the results; and the stability of the first, second and third cuneiform-metatarsal joints.

There are three main controversies regarding the surgical treatment of Lisfranc injuries: osteosynthesis versus primary arthrodesis; transarticular screws versus dorsal plates; and the most appropriate surgical approach.

The surgical treatment we prefer is open reduction and internal fixation (ORIF) with transarticular screws or with dorsal plates in cases of comminution of metatarsals or cuneiform bones.

Cite this article: EFORT Open Rev 2019;4:430-444. DOI: 10.1302/2058-5241.4.180076

Biomechanical Comparison of the Influences of 2 Proximal Metatarsal Osteotomies on First Ray Articular Contact Characteristics

Background:

An understudied area of proximal first metatarsal osteotomies is the effect on articular contact properties following the surgeries. Potential long-term risks include altered joint mechanics and possible arthritic progression. A biomechanical comparison of articular characteristics of the proximal opening wedge and Ludloff osteotomies was performed in this study. It was hypothesized that the proximal opening wedge osteotomy (POWO) would lead to greater alterations in articular contact properties along the first ray.

Methods:

Seven paired fresh-frozen below-knee cadaveric limbs with hallux valgus were selected. Specimens in each pair were tested in the intact state and then randomized to receive either a Ludloff or POWO. A 4-mm opening wedge osteotomy was used in all cases. Loading of the flexor hallucis longus was to 100 N using an instrumented tensioner. A 28-N load was added at the distal phalanx to simulate the ground reaction force. First metatarsophalangeal (MTP) and tarsometatarsal (TMT) articular properties were recorded simultaneously using 2 pressure sensors. For each state, a pressure map was generated and contact area, peak pressure, and center of pressure were calculated. Wilcoxon signed-rank test was used to assess statistical significance.

Results:

Average peak pressure was noted to be elevated at the MTP (4.6 vs 6.9 mPa, P = .04) and TMT (3.3 mPa vs 5.1 mPa, P = .30) joints when comparing the Ludloff and the POWO, respectively. Contact area was also noted to be lower in the POWO relative to the Ludloff for the MTP (86.6 vs 69.1 mm², P = .30) but not the TMT joints (89.1 vs 88.5 mm², P = .97). There was a slight plantar-lateral and dorsomedial shift in pressure at the MTP and TMT articulations, respectively, of the POWO relative to the Ludloff. A trend toward decreased contact force within the TMT joint was noted following opening wedge osteotomy relative to the intact state (103.8 vs 113.9 N, P = .31), while forces were elevated at the MTP joint (104.3 vs 96.0 N, P = .63), although not statistically significant. Smaller increases in TMT and MTP joint forces were noted following the Ludloff when compared to the intact state (95.6 vs 93.3 N at TMT and 109.2 vs 103.2 N at MTP).

Conclusion:

POWO can potentially change articular contact characteristics along the TMT and MTP articulations of the first ray. This could possibly lead to altered loading patterns and possible long-term damage vs other osteotomies.

Clinical Relevance:

While it is unlikely that the changes observed with the sizes of the osteotomy commonly used would lead to long-term significant clinical consequences, further study with larger group sizes would be beneficial.

The computed tomographybased anatomy of the ossa cuneiformia

There is a lack of basic anatomic information regarding the ossa cuneiformia. The aim of the present descriptive study was the detailed evaluation of the anatomy of the ossa cuneiformia. We analyzed 100 computer tomography scans of feet without deformities or previous trauma. The length, height and width of each cuneiforme and their articular surfaces were assessed. We itemized the data to gender differences and to foot length. The medial cuneiforme os had a length of 24.0 mm ± 2.4 (mean ± standard deviation), a width of 17.3 mm ± 2.8 and a height of 28.0 mm ± 3.4. The respective values for the intermediate cuneiforme were 18.2 mm ± 2.1, 15.8 mm ± 2.1 and 22.5 ± 2.2 and for the lateral cuneiforme 26.4 mm ± 2.7, 17.2 mm ± 2.9 and 22.8 mm ± 2.9. We found statistical relevant differences regarding gender and foot length subgroups whereas not for all parameters. The present study illustrates basic anatomic data regarding the ossa cuneiformia. This information might be helpful for implant design and placement during midfoot surgery.

Biomechanical Characteristics of Biplane Multiplanar Tension-Side Fixation for Lapidus Fusion

Although plating on the plantar, tension-side of the metatarsocuneiform joint provides an inherent biomechanical advantage for Lapidus arthrodesis, it has not been widely adopted owing to the morbidity associated with plantar application. To overcome these limitations, a modification to 90-90 locked biplanar plating was developed to provide the biomechanical advantages of multiplanar fixation and tension-side fixation, allowing application through a conventional incision. We tested the hypothesis that biplanar plating with tension-side fixation (low-profile straight dorsal plate and anatomic medial-plantar plate) would demonstrate improved mechanical stability compared with a previously tested 90-90 biplanar construct (small straight plate dorsally and medially) under cyclic loading. Both constructs were tested in static load to failure (3 pairs) and cyclic loading (10 pairs) with plantar cantilever bending using surrogate anatomic bone models. With static ultimate failure, the biplanar plate construct with tension-side fixation failed at a significantly greater failure load than did the straight biplanar plate construct (247.3 ± 18.4 N versus 210.9 ± 10.4 N; p = .04). With cyclic failure testing, the biplanar plate construct with tension-side fixation endured a significantly greater number of cycles (206,738 ± 49,103 versus 101,780 ± 43,273; p < .001) and a significantly greater dynamic failure load (207.5 ± 24.3 N versus 162.5 ± 20.6 N; p < .001) compared with the straight biplanar plate construct. These results have demonstrated that under simulated static and cyclic Lapidus arthrodesis loading, biplanar plating with tension-side fixation provides superior strength compared with the straight biplanar construct. Thus, this construct shows promise for clinical application as a practical approach to tension-side fixation and an early return to weightbearing after Lapidus fusion.

Surgical Treatment of Lisfranc Injury With Plantar Plate Approach

Midfoot injuries are the second most common athletic foot injury documented in the published data. High-energy Lisfranc dislocations are commonly seen secondary to traumatic etiologies and disrupt the strong midfoot ligaments supporting the arch. These injuries require immediate surgical intervention to prevent serious complications such as compartment syndrome and amputation. The present case series reports a new Lapidus plate system used in 3 patients who underwent arthrodesis procedures for Lisfranc joint dislocation. Three patients in their fourth to fifth decade of life presented with a traumatic injury at the Lisfranc joint and subsequently underwent open reduction and internal fixation using the plantar Lapidus Plate System (LPS; Arthrex, Naples, FL). The LPS was placed in a predetermined safe zone, with measures taken to avoid the insertional points of the tibialis anterior and peroneus longus tendons. Radiographs were obtained for ≤6 months postoperatively and revealed consolidation across the fusion site, intact hardware, and satisfactory alignment. On examination, the corrections were well maintained and free of signs of infection. Clinical evaluation showed no indication of motion within the tarsometatarsal joint and no tenderness to palpation surrounding the fusion sites. All 3 patients successfully returned to their activities of daily living without discomfort or pain. Modern surgical treatment of Lisfranc injuries most commonly includes open reduction and internal fixation, accompanied by arthrodesis. The present case series has demonstrated that the LPS provides relief, stability, and compression of the joint in our small cohort of patients who experienced a traumatic injury to the Lisfranc joint.

Proximal oblique metatarsal osteotomy for hallux valgus using a plantar locking plate

BACKGROUND

The purpose of this retrospective study was to evaluate the clinical and radiological results of hallux valgus surgery using a plantar locking plate.

METHODS

Proximal oblique metatarsal osteotomy combined with distal soft tissue treatment was performed in 59 adult patients (68 feet) with hallux valgus, using an anatomically pre-contoured plantar locking plate for fixation of the osteotomy. The median age was 64.0 years and the median follow-up period was 16.5 months.

RESULTS

The mean JSSF scale improved significantly from 56.0 points preoperatively to 95.8 points postoperatively. The mean intermetatarsal angle and hallux valgus angle decreased from 16.4° and 41.8° preoperatively to 4.2° and 10.8° postoperatively, respectively. The mean inclination angle was 19.9° preoperatively and 20.5° postoperatively. Removal of hardware was needed in 2 feet (2.9%).

CONCLUSIONS

Proximal oblique metatarsal osteotomy is an effective method for relief of pain and improvement of function in correction of hallux valgus deformity. Use of a plantar locking plate provides sufficient maintenance of the correction, and complications associated with the hardware are rare.

Effect of Fixation Type and Bone Graft on Tarsometatarsal Fusion

BACKGROUND:

End-stage tarsometatarsal (TMT) arthritis is commonly treated with arthrodesis of involved joints. Fixation hardware can consist of varying combinations of screws, plates, and staples with or without supplemental bone graft. There are limited data to demonstrate either superiority of a given fixation method or the impact of bone graft on fusion rates. The purpose of this study, therefore, was to determine whether nonunion rates after TMT arthrodesis were influenced by either the use of screw vs plate fixation or the addition of bone graft vs no bone graft.

METHODS:

All patients older than 18 years undergoing arthrodesis for TMT arthritis between July 1991 and July 2016 were identified retrospectively. Exclusion criteria included less than 12 months follow-up, prior midfoot surgery, any added procedure beyond TMT arthrodesis using plates or screws, and acute foot trauma. All patients with radiographic or clinical nonunion, including those requiring revision surgery, were identified. Demographic data and associated risk factors were recorded via chart and radiographic image review. Eighty-eight patients (88 feet, mean follow-up: 75.1 ± 51.4; range, 12-179), with a total of 189 joints and who met enrollment criteria were treated by 9 different surgeons with arthrodesis.

RESULTS:

The overall nonunion rate was 11.4%. Significant independent risk factors associated with nonunion were (1) arthrodesis using plate fixation with all screws through the plate (odds ratio [OR], 6.2; 95% confidence interval [CI], 1.8-21.3; P = .004), (2) smoking during the perioperative period (OR, 7.9; 95% CI, 2.1-30.2; P = .002), and (3) postoperative nonanatomic alignment (OR, 11.2; 95% CI, 2.1-60.8; P = .005). Bone graft utilization was found to significantly lower the rate of nonunion (OR, 0.2; 95% CI, 0.1-0.6; P = .006).

CONCLUSION:

Isolated plate fixation, smoking, and postoperative nonanatomic alignment appear to significantly increase the rate of nonunion among patients undergoing TMT arthrodesis for midfoot arthritis. Concomitant use of autogenous bone graft significantly decreased this risk.

LEVEL OF EVIDENCE:

Level III, retrospective comparative study.

Stability of Locking Plate and Compression Screws for Lapidus Arthrodesis: A Biomechanical Comparison of Plate Position

Lapidus (first tarsometatarsal joint) arthrodesis is an established and widely used procedure for the management of moderate to severe hallux valgus, especially in cases involving hypermobility of the first tarsometatarsal joint. Multiple fixation methods are available, and several previous investigations have studied the relative strengths of these methods, including dorsomedial and plantar plating comparisons. However, these studies compared plates of varying designs and mechanical properties and used varying modes of compression and interfragmentary screw techniques. The present study mechanically investigated the resulting motion, stiffness, and strength of identical locking plate constructs fixed at various anatomic positions around the first tarsometatarsal joint. In a bench-top study, fourth-generation composite bones were divided into 3 fixation groups, each having identical interfragmentary screw applications, and randomized to 1 of 3 plate positions: dorsal, medial, or plantar. The plates applied in each case were identical locking plates, precontoured to fit the anatomy. Each construct was experimentally tested using a cantilever bending approach. The outcomes obtained were stiffness, yield force, displacement at yield, ultimate force, and displacement at ultimate force. The plantar plate position showed superior initial stiffness and force to ultimate failure. The plantar and medial plate positions exhibited superior force to yield. The medial plate position was superior regarding displacement tolerated before the yield point and catastrophic failure. The dorsal plate position was not superior for any outcome measured. Plantar and medial plating each offered biomechanical benefits. Clinical studies using similarly matched constructs are required to show whether these findings translate into improved clinical outcomes.

Preliminary results of a plantar plate for Lapidus arthrodesis

The TMT I arthrodesis is an established procedure for the correction of hallux valgus deformity associated with the instability of the TMT-I joint. A risk of transfer metatarsalgia is reported in the literature associated with persistant elevation of MT-I. Detailed information for ideal positioning of the arthrodesis is missing so far. Clinical, radiological and padobarografical results and their correlations were analyzed with special consideration of the elevation position of the MT-I in a TMT-I arthrodesis using the plantar plate osteosynthesis. Postoperative changes in plantar pressure and force distribution occured after TMT-I arthrodesis. A postoperative increase of the load under the medial forefoot and the dependence on the positioning of MT-I in the sagittal plane has been shown. The authors suggest, that increased load of the medial forefoot and constant pressures and forces under the central forefoot may lead to a relative relief of the area, which might explain the postoperative reduction of metatarsalgia.

Biomechanics of common fixation devices for first tarsometatarsal joint fusion-a comparative study with synthetic bones

BACKGROUND

Hallux valgus disease is a common deformity of the forefoot. There are currently more than 100 surgical approaches for operative treatment. Because hypermobility of the first tarsometatarsal joint is considered to be causal for hallux valgus disease, fusion of the tarsometatarsal joint is an upcoming surgical procedure. Despite the development of new and increasingly stable fixation devices like different locking plates, malunion rates have been reported in 5 to 15% of cases.

METHODS

Biomechanical comparison of three commonly used fixation devices (a dorsal locking plate, a plantar locking plate, and an intramedullary fixation device) was performed by weight-bearing simulation tests on synthetic bones. Initial compression force and stiffness during simulation of postoperative weight-bearing were analysed.

RESULTS

Fixation of the first tarsometatarsal joint with the plantar plate combination demonstrated a higher stiffness compared to fixation with the intramedullary implant or the medial locking plate. The intramedullary device provided the highest initial compression force. Failure was detected in the following ranking: (1) the angle-stable intramedullary fixation device, (2) the medial located plate, and (3) the plantar locking plate.

CONCLUSION

The intramedullary device demonstrated the highest initial compression force of the three tested implants. The plantar locking plate showed the best overall stability during weight-bearing simulation. Further clinical research is necessary to analyse if the intramedullary fixation device needs a longer period of non-weight-bearing to reach a better non-union rate compared to the plantar locking plate.

Appropriate Area for Operative Procedures Near Tibialis Anterior Tendon Insertion: A Cadaveric Study

BACKGROUND

The tibialis anterior tendon has its insertion sites on both the medial and plantar surfaces of the medial cuneiform and the base of the first metatarsal. Operative procedures near those areas, especially at the first metatarsocuneiform joint, may disturb tendon insertions and cause irritation or functional impairment of the tendon.

METHODS

Tibialis anterior tendons and their insertion sites were dissected and examined from 46 cadaveric feet (19 female and 27 male cadavers, aged between 33 and 86 years, with a mean of 68.5 ± 14.3 years). The greatest lengths and widths of the tendon attachments on the bony surface of the medial cuneiform and base of the first metatarsal, on both the medial and plantar surfaces, were measured and analyzed. The measurement reliability was evaluated by using the intraclass correlation coefficient.

RESULTS

Most of the tibialis anterior tendon insertions were found to be longer at the medial cuneiform than at the base of the first metatarsal (mean, 8.3 and 5.4 mm; P < .001), but the widths were almost similar (mean, 11.0 and 10.4 mm; P = .079). When focusing on each bone, the widths of the tendon attachments on the medial and plantar surfaces of the medial cuneiform were equivalent (mean, 5.4 and 5.6 mm; P = .584). At the base of the first metatarsal, the tendon attachment on the plantar surface was found to be wider than on the medial surface (mean, 7.0 and 3.4 mm; P < .001).

CONCLUSION

The widths of the tibialis anterior tendon insertions on the medial and plantar surfaces of the medial cuneiform were equal, as were the total widths of insertions on the medial cuneiform and on the base of the first metatarsal. However, the width of insertions on the medial surface of the first metatarsal was significantly smaller than on the plantar surface, and the total length of insertions at the medial cuneiform was longer than at the first metatarsal.

CLINICAL RELEVANCE

This study provides information about characteristics of the tibialis anterior tendon insertions, particularly details of the dimensions on each surface of the bones. This knowledge enables surgeons to minimize the risk of irritation or tendon injuries during operations near the base of the first metatarsal and medial cuneiform area.

Biomechanical Comparison of Fixation Devices for First Metatarsocuneiform Joint Arthrodesis

Common surgical treatment of first tarsal-metatarsal arthritis is by first metatarsocuneiform joint arthrodesis. While crossed-screw and locking plate fixation are the most widely used methods, a novel construct was designed to alleviate soft tissue irritation while still providing stable fixation. Using anatomic first metatarsal and medial cuneiform composites, we compared 3 arthrodesis implants (crossed-screw, dorsal locking plate, and IO Fix) under 2 cyclic bending loading scenarios (cantilever and 4-point bending). Additionally, the optimal orientation (plantar-dorsal or dorsal-plantar) of the IO Fix construct was determined. Failure load, diastasis, joint space angle, and axial and angular stiffness were determined. Both crossed-screw fixation and the IO Fix constructs experienced significantly higher failure loads than the dorsal locking plate during both loading scenarios. Additionally, they had lower plantar diastasis and joint space angle at failure than the plate. Moreover, the plantar-dorsal IO Fix construct was significantly stiffer than the crossed-screw during cantilever bending. Finally, the plantar-dorsal orientation of the IO Fix device had higher failure load and lower diastasis and angle at failure than in the dorsal-plantar orientation. The results suggest that the IO Fix system can reduce motion at the interfragmentary site and ensure compression for healing comparable to that of the crossed-screw fixation.

LEVELS OF EVIDENCE

Level V: Bench testing.

Comparison of Locking Plate with Interfragmentary Screw Versus Plantarly Applied Anatomic Locking Plate for Lapidus Arthrodesis: A Biomechanical Cadaveric Study

Arthrodesis of the first metatarsal cuneiform joint, or Lapidus procedure, is a widely accepted treatment for hallux valgus. Recent studies have focused on comparing various constructs for this procedure both in the laboratory and clinical settings. The current study compared in a cadaveric model the strength of 2 constructs. The first construct utilized a medially applied low-profile locking plate and an interfragmentary screw directed from plantar-distal to dorsal-proximal. The second construct consisted of a plantarly applied plate with a compression screw placed through the plate from plantar-distal to dorsal-proximal. The ultimate load to failure for the 2 groups tested was 255.38 ± 155.38 N and 197.48 ± 108.61 N, respectively (P = .402). There was no significant difference found between the 2 groups with respect to ultimate load to failure, stiffness of the construct, or moment at time of failure. In conclusion, the medially applied plate with plantar interfragmentary screw appears to be stronger than the plantar Lapidus plate tested for first metatarsal cuneiform arthrodesis, though this difference did not reach statistical significance.

LEVELS OF EVIDENCE

Level V: Biomechanical Study.

[Lapidus arthrodesis]

The tarso-metatarsal 1 joint (TMT-I) arthrodesis is a treatment option or moderate to severe hallux valgus (HV) deformities. Instability of the TMT1 joint is still a debatable indication. Using stable osteosynthesis techniques allows early postoperative weight bearing. Plantar plating combined with a lag screw is the biomechanical most stable construct. An additional intermetatarsal screw can improve the horizontal stability. Clinical results are good and radiological parameters stay constant, even in the long term.

Biomechanical investigation of two plating systems for medial column fusion in foot

Background

Arthrodesis of the medial column (navicular, cuneiform I and metatarsal I) is performed for reasons such as Charcot arthropathy, arthritis, posttraumatic reconstruction or severe pes planus. However, the complication rate is still high and mainly resulting from inadequate fixation. Special plates, designed for medial column arthrodesis, seem to offer potential to reduce the complication rate. The aim of this study was to investigate biomechanically plantar and dorsomedial fusion of the medial column using two new plating systems.

Methods

Eight matched pairs of human cadaveric lower legs were randomized in two groups and medial column fusion was performed using either plantar or dorsomedial variable-angle locking compression plates. The specimens were biomechanically tested under cyclic progressively increasing axial loading with physiological profile of each cycle. In addition to the machine data, mediolateral x-rays were taken every 250 cycles and motion tracking was performed to determine movements at the arthrodesis site. Statistical analysis of the parameters of interest was performed at a level of significance p = 0.05.

Results

Displacement of the talo-navicular joint after 1000, 2000 and 4000 cycles was significantly lower for plantar plating (p≤0.039) while there was significantly less movement in the naviculo-cuneiform I joint for dorsal plating post these cycle numbers (p<0.001). Displacements in all three joints of the medial column, as well as angular and torsional deformations between the navicular and metatarsal I increased significantly for each plating technique between 1000, 2000 and 4000 cycles (p≤0.021). The two plating systems did not differ significantly with regard to stiffness and cycles to failure (p≥0.171).

Conclusion

From biomechanical point of view, although dorsomedial plating showed less movement than plantar plating in the current setup under dynamic loading, there was no significant difference between the two plating systems with regard to stiffness and cycles to failure. Both tested techniques for dorsomedial and plantar plating appear to be applicable for arthrodesis of the medial column of the foot and other considerations, such as access morbidity, associated deformities or surgeon's preference, may also guide the choice of plating pattern. Further clinical studies are necessary before definitive recommendations can be given.

A new "tension side" locking plate for Hallux Valgus: A prospective multicentre case series

BACKGROUND

Proximal osteotomy of the first metatarsal is often indicated for Hallux Valgus correction. Previously recognised complications however, include transfer metatarsalgia, first metatarsophalangeal joint stiffness, problems with fixation and prominence of metalware.

METHODS

We report on one year follow up of an international prospective series between June 2009 and October 2012 involving three centres, including 91 feet (58 patients) that underwent proximal osteotomy, using a new locking plate applied to the plantar surface of the metatarsal.

RESULTS

Mean Hallux Valgus angle improved from 27.9 (±13.1)° to 12.4 (±8.2)° while mean Intermetatarsal angle improved from 12.5 (±8.4) to 7.1 (±3.4) and there was a statistically significant improvement in both mean AOFAS-HMI score 54.2 (±13.9) to 94.0 (±9.5) and Visual Analogue Pain Scale 4.7 (±1.5) to 0.6 (±1.3). 70% of patients were back at their preoperative employment at five weeks. Mean surgical time was 56min and the plate was generally well tolerated. There were five implant related complications.

CONCLUSIONS

Locked fixation from the tension side of the construct encourages early weight bearing with a low risk of implant prominence. Our radiological, functional and clinical parameters are comparable with similar series and we therefore recommend this technique.

Placement of Plantar Plates for Lapidus Arthrodesis: Anatomical Considerations

BACKGROUND

The modified Lapidus procedure is an accepted treatment option for patients with moderate to severe hallux valgus. Placing a plate plantar on the tension side of the arthrodesis has been shown to be biomechanically superior and has provided good clinical results. There is some concern about interference of the plantar placed plates on the tendon insertions. The purpose of this study was to determine a "safe zone" for plantar plate placement without irritation of the tendons.

METHODS

Twenty-nine embalmed right feet were used for this study. The anatomy of the insertion of the peroneus longus (PL) tendon and tibialis anterior (TA) tendon on the medial cuneiform and first metatarsal were analyzed. Six different plate designs for plantar plating of the first tarsometatarsal fusion were included. The fit to the bone and contact to tendon insertion were analyzed.

RESULTS

The PL showed a main insertion to the first metatarsal and a lesser insertion to the medial cuneiform. The TA inserted onto the medial cuneiform and first metatarsal in all cases in our series. There was a "safe zone" between the TA and PL insertion areas for plate placement. Straight, Y- and U-shaped plates could be placed without compromising the tendon insertion. Depending on the design, even preshaped plates may have to be bent to allow a good fit to the plantar side of the first tarsometatarsal joint.

CONCLUSION

Plantar plating for modified Lapidus arthrodesis can be safely performed, without damaging the plantar tendon insertion area of the PL and TA.

CLINICAL RELEVANCE

The exact knowledge of the anatomy of the plantar region of the tarsometatarsal joint can help to improve plate placement.

Endosseous Fixation Device for Lapidus Arthrodesis: Technique, Early Experience, and Comparison With Crossed Screw Fixation

First metatarsal cuneiform joint arthrodesis has been commonly used since the early 1900s for definitive treatment of a variety of conditions involving the medial column of the foot. Early applications of this procedure resulted in a relatively high rate of complications, including malunion and nonunion. We retrospectively examined a novel method of fixation involving an endosseous implant with a nonporous, rough exterior surface and compared it with the traditional crossed screw fixation, considered the standard of care for the procedure. Twenty-one feet in 19 patients served as the control group with crossed screws, and 18 feet in 17 patients served as the trial group using the study device. Null hypothesis testing was used to compare the outcomes parameters between the comparative groups. Postoperatively, the patients were allowed to walk in a prefabricated, removable, below-the-knee cast boot at a mean of 48.3 ± 8.2 days in the control group and 24.4 ± 9.7 days in the trial group. These differences were highly significant (p < .0001). Postoperatively, the patients were allowed to walk in a stiff-soled shoe at a mean of 65.2 ± 8.4 days in the control group and 49.7 ± 19.2 days in the trial group. These differences were also statistically significant (p = .0020). The patients in the control group required revision surgery in 7 of 21 procedures (33%), with 2 patients developing nonunion (9.5%). Only 1 patient in the trial group required revision surgery (5.8%), and no patient developed nonunion. From these results, we believe that the endosseous trial implant is a reliable option for fixation of the first metatarsal cuneiform arthrodesis procedure and might allow for earlier weightbearing with fewer postoperative complications.

Immediate fullweightbearing after tarsometatarsal arthrodesis for hallux valgus correction--Does it increase the complication rate?

BACKGROUND

The arthrodesis of the first tarsometatarsal joint has a high correction potential in the treatment of hallux valgus deformity. Compared to distal correction procedures, a pseudarthrosis rate of 12-20% is quoted, however. In a prospective study the results of two different treatment procedures after correction arthrodesis were compared.

METHODS

In 17 cases the patients were mobilised with a short arthrodeses shoe with floor contact (NWB group) and in 17 cases in a short arthrodeses shoe with immediate fullweightbearing (FWB group). Clinical and radiological evaluation was done preoperatively, six weeks and one year postoperatively, including visual analogue pain scale and AOFAS score pre- and one year postoperatively.

RESULTS

There was no increased complication rate in the group with FWB group. The patients in the FWB group were significantly earlier fit for work.

CONCLUSION

Immediate fullweightbearing after TMT I arthrodesis using a plantar plate should be established as a standard posttreatment.

Crossed-screws provide greater tarsometatarsal fusion stability compared to compression plates

BACKGROUND

Hallux valgus is a common deformity that is often treated with a fusion of the first tarsometatarsal (TMT) joint. Crossed-screws are currently the accepted standard but advances in plate systems present opportunities for improved clinical outcomes; however, in vitro testing should be performed prior to clinical implementation. The purpose of this study was to determine whether a locking plate with surgeon-mediated compression provides similar fusion stability compared to crossed-screws and if bone density or joint size are related to construct success.

METHODS

Ten matched-pair cadaveric specimens received first TMT fusions with either crossed-screws or a compression plate and were loaded for 1000 cycles to assess the amount of joint motion measured as plantar gapping. Bone density was quantified using computed tomography images of each specimen, and joint height was measured with calipers.

RESULTS

Crossed-screws provided 3 times greater resistance to plantar gapping compared to compression plates after 1000 cycles. Bone density and joint size did not affect resistance to plantar gapping for either construct.

CONCLUSION

Lag screws or a plantarly applied plate are needed to maximize TMT fusion stability prior to osseous union. Dorsomedially applied plates are also effective when paired with a lag screw placed across the TMT joint. These constructs do not appear to depend on bone density or joint size, suggesting that patients with osteoporosis are viable candidates.

CLINICAL RELEVANCE

The results of this study suggest that traditional, lagged cross-screws provide greater stability to that of a dorsally place compression plate and may lead to better rates of union.

LEVELS OF EVIDENCE

Therapeutic, Level V: Cadaveric Study.

First Tarsometatarsal Arthrodesis: An Anatomic Evaluation of Dorsomedial Versus Plantar Plating

Fusion of the first tarsometatarsal joint is a widely used procedure for the correction of hallux valgus deformity. Although dorsomedial H-shaped plating systems are being increasingly used, fusion can also be achieved by plantar plating. The goal of the present study was to compare these 2 operative techniques based on the anatomic considerations and show the potential pitfalls of both procedures. Six pairs of deep-frozen human lower legs were used in the present cadaveric study. In a randomized manner, either dorsomedial arthrodesis or plantar plating through a medial incision was performed. With regard to arterial injury, the plantar technique resulted in fewer lesions (plantar, 4 injuries [66.7%] to the terminal branches of the first digital branch of the medial plantar artery; dorsomedial, 3 injuries [50%] to the main trunks of the plantar metatarsal arteries and the first dorsal metatarsal artery). With respect to injury to the veins, the plantar procedure affected significantly fewer high-caliber subcutaneous trunk veins. The nerves coursing through the operative field, such as the saphenous and superficial fibular nerves, were compromised more often by the dorsal approach. Neither the plantar plating nor the dorsomedial plating technique was associated with injury to the insertion of the tibialis anterior muscle. Both studied techniques are safe, well-established procedures. Arthrodesis with plantar plating, however, offers additional advantages and is a reliable tool in the foot and ankle surgeon's repertoire.

Intraosseous fixation compared to plantar plate fixation for first metatarsocuneiform arthrodesis: a cadaveric biomechanical analysis

BACKGROUND

Metatarsocuneiform (MTC) fusion is a treatment option for management of hallux valgus. We compared the biomechanical characteristics of an internal fixation device with plantar plate fixation.

METHODS

Seven matched pairs of feet from human cadavers were used to compare the intramedullary (IM) device plus compression screw to plantar plate combined with a compression screw. Specimen constructs were loaded in a cyclic 4-point bending test. We obtained initial/final stiffness, maximum load, and number of cycles to failure. Bone mineral density was measured with peripheral quantitative computed tomography. Performance was compared using time to event analysis with number of cycles as time variable, and a proportional hazard model including shared frailty model fitted with treatment and bone mineral density as covariates.

RESULTS

On average the plates failed after 7517 cycles and a maximum load of 167 N, while the IM-implants failed on average after 2946 cycles and a maximum load of 69 N. In all pairs the 1 treated with IM-implant failed earlier than the 1 treated with a plate (hazard ratio for IM-implant versus plate was 79.9 (95% confidence interval [6.1, 1052.2], P = .0009). The initial stiffness was 131 N/mm for the plantar plate and 43.3 N/mm for the IM implant. Initial stiffness (r = .955) and final stiffness (r = .952) were strongly related to the number of cycles to failure. Bone mineral density had no effect on the number of cycles to failure.

CONCLUSION

Plantar plate fixation created a stronger and stiffer construct than IM fixation.

CLINICAL RELEVANCE

A stiffer construct can reduce the risk of nonunion and shorten the period of non-weight-bearing.

Immediate weightbearing after Lapidus arthrodesis with external fixation

A common surgical treatment of severe hallux abductovalgus deformity with coincident first ray hypermobility is metatarsal-cuneiform fusion or Lapidus procedure. The aim of the present study was to illustrate a reliable and novel method of fixation for Lapidus fusion using an external fixation device through a retrospective cohort investigation of consecutive patients. Twenty Lapidus fusions were performed in 19 patients, including 17 females (89.47%) and 2 males (10.53%). The mean age at surgery was 41 (range 20 to 64) years. The patients were evaluated clinically and radiographically pre- and postoperatively. The mean duration in the fixator was 12 (range 3 to 34) weeks. The mean interval to radiographic union was 9.2 (range 4.7 to 30.7) weeks in 18 of 20 feet (90%) and 2 (10%) were designated as nonunion. The mean follow-up period was 37 (range 5.6 to 211.1) weeks. The most common complication was pin tract infection in 5 patients (6 feet) and was treated with oral antibiotics; only 1 foot required early hardware removal. According to the visual analog scale, the mean patient pain score decreased significantly from 8.2 ± 2.7 to 0.83 ± 0.98 postoperatively (p < .001). Our results highlight that immediate weightbearing after Lapidus fusion with external fixation is a viable treatment option for the correction of severe hallux abductovalgus with associated hypermobility.

Biomechanical analysis of two fixation methods for proximal chevron osteotomy of the first metatarsal

PURPOSE

The proximal chevron osteotomy provides high correctional power. However, relatively high rates of dorsiflexion malunion of up to 17 % are reported for this procedure. This leads to insufficient weight bearing of the first ray and therefore to metatarsalgia. Recent biomechanical and clinical studies pointed out the importance of rigid fixation of proximal metatarsal osteotomies. Therefore, the aim of the present study was to compare biomechanical properties of fixation of proximal chevron osteotomies with variable locking plate and cancellous screw respectively.

METHODS

Ten matched pairs of human fresh frozen cadaveric first metatarsals underwent proximal chevron osteotomy with either variable locking plate or cancellous screw fixation after obtaining bone mineral density. Biomechanical testing included repetitive plantar to dorsal loading from 0 to 31 N with the 858 Mini Bionix(®) (MTS(®) Systems Corporation, Eden Prairie, MN, USA). Dorsal angulation of the distal fragment was recorded.

RESULTS

The variable locking plate construct reveals statistically superior results in terms of bending stiffness and dorsal angulation compared to the cancellous screw construct. There was a statistically significant correlation between bone mineral density and maximum tolerated load until construct failure occurred for the screw construct (r = 0.640, p = 0.406).

CONCLUSION

The results of the present study indicate that variable locking plate fixation shows superior biomechanical results to cancellous screw fixation for proximal chevron osteotomy. Additionally, screw construct failure was related to levels of low bone mineral density. Based on the results of the present study we recommend variable locking plate fixation for proximal chevron osteotomy, especially in osteoporotic bone.

Modified Lapidus arthrodesis with plantar plate and compression screw for treatment of hallux valgus with hypermobility of the first ray: a preliminary report

BACKGROUND

TMT-1 arthrodesis is an established method in hallux valgus surgery, but it is technically demanding and typically calls for a period of postoperative immobilization.

METHODS

In this cohort study, initial experience with a plantar plate is described. 58 patients (59 arthrodesis) were included.

RESULTS

The mean duration of protected full weight bearing was 7 weeks. 94.12% patients were satisfied with the results, bony union was achieved in 98.31%. The Foot Function Index improved by 33 to a mean of 8 (p<.001). The postoperative Mayo Clinic Forefoot Score was excellent in 47.04 and good in 47.04%. The mean hallux valgus angle improved by 24.4-13.2° (p<.001). The mean first intermetatarsal angle improved by 11.2-5.2° (p<.001).

CONCLUSION

Initial experience with this form of fixation appears to provide suitable stability, allow early-protected weight bearing, with an acceptable level of complications.

Comparative study of Lapidus bunionectomy using different osteosynthesis methods

The treatment of hallux valgus in patients with pathology of the first tarsometatarsal (TMT I) joint by fusion is an established procedure. Multiple osteosynthesis methods for the fixation of the TMT I joint are available. In comparison to the distal procedures the Lapidus bunionectomy is associated with a pseudarthrosis rate of up to 12% [9-11]. We present results after TMT-I arthrodesis using an interfragmentary screw and a plantar plate compared with an interfragmentary screw and a dorsomedial locking plate. Clinical and radiological examinations were performed preoperatively, six weeks and one year postoperatively. The AOFAS (American Orthopaedic Foot and Ankle Society) score and Visual Analogue Pain Scale (VAS) were evaluated preoperatively and 12 months after surgery. We observed a significantly increased rate of undesirable effects in mediodorsal plate positioning.