Screw fixation compared to H-locking plate fixation for first metatarsocuneiform arthrodesis: a biomechanical study

Comparison of 4 Different Fixation Strategies for Midfoot Arthrodesis: A Retrospective Comparative Study

BACKGROUND

Midfoot arthrodesis is a common procedure performed both for arthritis and correction of deformity. The optimal fixation for midfoot arthrodesis has not been established, though numerous studies have been investigating the fixation techniques of midfoot arthrodesis. The purpose of this study was to compare the union rate of midfoot arthrodesis using 4 different fixation strategies and investigate risk factors of nonunion following midfoot arthrodesis.

METHODS

A retrospective chart review was performed for patients who underwent midfoot joint arthrodesis between January 2014 and May 2019. The rates of nonunion and postoperative complication were compared among 4 different fixation constructs: staple fixation, compression plate fixation, compression plate with lag screw fixation, and compression screw fixation. Predictors of nonunion following midfoot arthrodesis were investigated through a multivariable logistic regression analysis. A total of 95 patients (99 feet), including 240 midfoot joints were included in this study. The mean follow-up period was 78.4 weeks.

RESULTS

Overall, bony union was achieved in 86 out of 99 (86.9%) patients, which included 218 out of 240 (90.8%) midfoot joints. A significant difference in the nonunion rate according to the type of fixation construct was found (P = .011); the compression screw alone fixation construct was noted to have a significantly higher nonunion rate than other fixation constructs. Diabetes mellitus (odds ratio [OR] = 0.179 [95% CI: 0.059, 0.542]), the type of fixation construct (compression screw alone; OR =1.789 [95% CI: 1.071, 2.978]), lack of adjuvant bone graft (OR = 2.803 [95% CI: 1.081, 7.268], and postoperative nonanatomical alignment (OR = 3.937 [95% CI: 1.278, 12.126]) were identified as independent predictors of nonunion following midfoot arthrodesis.

CONCLUSION

The rate of nonunion following midfoot arthrodesis among 4 different commonly used fixation constructs was compared in this study. Risk factors of nonunion were investigated revealing that diabetes mellitus, compression screw fixation alone, lack of adjuvant bone graft, and postoperative nonanatomical alignment are independent predictors of nonunion following midfoot arthrodesis.

LEVELS OF EVIDENCE

Level III: Comparative cohort study.

The Efficiency of Highly Porous β-Tricalcium Phosphate With Bone Marrow Aspirate Concentrate in Midfoot Joint Arthrodesis

BACKGROUND

Nonunion is one of the most common and devastating complications following midfoot joint arthrodesis. Many different types of bone grafts and bone substitutes have been used to promote osseous fusion. However, there is no consensus on the gold standard bone grafting material and whether biologic materials should be used alone or in combination. The purpose of this study is to investigate the efficiency of highly porous β-tricalcium phosphate (β-TCP) with bone marrow aspirate concentrate (BMAC) in midfoot joint arthrodesis.

METHODS

This retrospective comparative study included patients who underwent midfoot joint arthrodesis using compression screws. Patients were classified into 2 groups: arthrodesis with highly porous β-TCP and BMAC (group A) and arthrodesis without them (group B). The osseous union rate was compared between the 2 groups. A total of 44 patients (46 feet) including 89 joints were included in this study.

RESULTS

There was a significant difference in the union rate between the 2 groups: 91.5% (43/47 joints) in arthrodesis with highly porous β-TCP and BMAC (group A) and 76.2% (32/42 joints) in arthrodesis without highly porous β-TCP and BMAC (group B; P = .048).

CONCLUSION

This study investigated the efficiency of highly porous β-TCP and BMAC to promote bony healing in midfoot joint arthrodesis. A significantly higher union rate was shown when arthrodesis was performed with highly porous β-TCP and BMAC, compared with arthrodesis performed without them. We suggest that highly porous β-TCP and BMAC can be a viable and effective adjunct to the fixation in midfoot joint arthrodesis.

LEVEL OF EVIDENCE

Level III: Retrospective comparative analysis.

First Tarsometatarsal Joint Fusion in Foot-A Biomechanical Human Anatomical Specimen Analysis with Use of Low-Profile Nitinol Staples Acting as Continuous Compression Implants

Background and Objectives: The aim of this study was to investigate under dynamic loading the potential biomechanical benefit of simulated first tarsometatarsal (TMT-1) fusion with low-profile superelastic nitinol staples used as continuous compression implants (CCIs) in two different configurations in comparison to crossed screws and locked plating in a human anatomical model. Materials and Methods: Thirty-two paired human anatomical lower legs were randomized to four groups for TMT-1 treatment via: (1) crossed-screws fixation with two 4.0 mm fully threaded lag screws; (2) plate-and-screw fixation with a 4.0 mm standard fully threaded cortex screw, inserted axially in lag fashion, and a 6-hole TMT-1 Variable-Angle (VA) Fusion Plate 2.4/2.7; (3) CCI fixation with two two-leg staples placed orthogonally to each other; (4) CCI fixation with one two-leg staple and one four-leg staple placed orthogonally to each other. Each specimen was biomechanically tested simulating forefoot weightbearing on the toes and metatarsals. The testing was performed at 35-37 °C under progressively increasing cyclic axial loading until construct failure, accompanied by motion tracking capturing movements in the joints. Results: Combined adduction and dorsiflexion movement of the TMT-1 joint in unloaded foot condition was associated with no significant differences among all pairs of groups (p ≥ 0.128). In contrast, the amplitude of this movement between unloaded and loaded foot conditions within each cycle was significantly bigger for the two CCI fixation techniques compared to both crossed-screws and plate-and-screw techniques (p ≤ 0.041). No significant differences were detected between the two CCI fixation techniques, as well as between the crossed-screws and plate-and-screw techniques (p ≥ 0.493) for this parameter of interest. Furthermore, displacements at the dorsal and plantar aspects of the TMT-1 joint in unloaded foot condition, together with their amplitudes, did not differ significantly among all pairs of groups (p ≥ 0.224). Conclusions: The low-profile superelastic nitinol staples demonstrate comparable biomechanical performance to established crossed-screws and plate-and-screw techniques applied for fusion of the first tarsometatarsal joint.

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.

First Tarsometatarsal Joint Fusion for Hallux Valgus Deformity: A Retrospective Comparison of Two Fixation Constructs Regarding Initial Maintenance of Correction and Complications: Traditional Crossing Screw Fixation Versus Dorsomedial Locking Plate and Intercuneiform Compression Screw

Various fixation constructs exist to address hallux valgus when performing a first tarsometatarsal joint arthrodesis. The goal of this present study is to compare complication rates, and degree and maintenance of angular correction between a dorsomedial locking plate with intercuneiform compression screw construct versus traditional crossing solid screw fixation construct. The plate plus intercuneiform compression screw construct fixation utilized a combined sagittal saw and curette method of joint preparation while the crossed screw fixation group utilized a curette and bur technique. A retrospective review was conducted of consecutive patients who underwent a midfoot fusion using either constructs. Sixty four total feet in 56 patients were enrolled in the study. Twenty four consecutive patients (32 feet) who underwent a midfoot arthrodesis using the locking plate and intercuneiform fixation were fully fused (100%) by 10 weeks postoperatively, with no incidents of nonunion and one deep vein thrombosis event. Thirty two consecutive patients (32 feet) who underwent midfoot arthrodesis with crossing screw fixation had 2 nonunion events, one that was asymptomatic and the other that required a revision midfoot fusion. There was a statistically significant improvement from the pre-operative intermetatarsal angle, hallux abductus angle compared to the 10 week and 1 year radiographs (p < .05) for the entire cohort for both fixation constructs. There was a statistically significant increase in American College of Foot and Ankle Surgery first ray scores from pre-op to 1 year follow-up for both fixation constructs. Overall, the dorsomedial locking plate plus intercuneiform compression screw fixation construct better maintains Intermetatarsal angle (IMA) correction at midterm follow-up compared to the traditional crossing screw construct. Both cohorts overall demonstrate similar fusion rates at 10 weeks, nonunion events, incidences of broken hardware, hardware removal, deep vein thrombosis, neuritis at 1 year postoperatively, and hallux varus.

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.

Surgical controversies and current concepts in Lisfranc injuries

INTRODUCTION

Lisfranc injuries, not as rare as previously reported, range from ligamentous to complex fracture-dislocations. Anatomical studies have identified a complex of discrete structures, and defined the anatomical characteristics of the Lisfranc joint.

SOURCES OF DATA

A narrative evidence-based review encompassed and analyzed published systematic reviews. Outcomes included clinical and surgical decision-making, including clinical-presentation, diagnosis, pathological-assessment, surgical-management techniques and indications, post-surgical care and comparative outcomes.

AREAS OF AGREEMENT

Better understanding of the Lisfranc complex anatomy aids surgical treatment and tactics. Prognosis is related to injury severity, estimated by the number of foot columns affected. Surgical outcome is determined by anatomical reduction for most fixation and fusion techniques. Appropriate treatment allows return to sport, improving outcome scores.

AREAS OF CONTROVERSY

Identification of Lisfranc injuries may be improved by imaging modalities such as weight-bearing computer tomography. Recent evidence supports dorsal plate fixation as a result of better quality of reduction. In complex injuries, the use of combined techniques such as trans-articular screw and plate fixation has been associated with poorer outcomes, and fusion may instead offer greater benefits.

GROWING POINTS

Open reduction is mandatory if closed reduction fails, highlighting the importance of understanding surgical anatomy. If anatomical reduction is achieved, acute arthrodesis is a safe alternative to open reduction internal fixation in selected patients, as demonstrated by comparable outcomes in subgroup analysis.

AREAS FOR DEVELOPING RESEARCH

The current controversies in surgical treatment remain around techniques and outcomes, as randomized controlled trials are infrequent.

A Comparison of Trans-Articular Screw Versus Dorsal Bridge Plate Versus Compression Locking Plate Fixation in B2 Lis Franc Injuries: A 5-Year Experience in a Level 1 Trauma Center, in the United Kingdom

This retrospective case series aimed to identify whether trans-articular screws, dorsal bridging plates or if a 4-corner compression plate offers better functional outcome after B2 Lis Franc injuries. Thirty-eight patients underwent surgical fixation for these injuries over 5 years in a Level 1 Trauma Centre. Patients were treated in 1 of 3 treatment arms: trans-articular screw, dorsal bridge plate, or 4-corner compression plate fixation. The primary outcome measures were the Manchester Oxford Foot and Ankle Questionnaire and the Euroqol- 5DL score and surgical results included postoperative complications and further surgery. Injury type, energy of mechanism, and open versus closed status were not significantly different within any fixation group. We achieved 94.7% (n = 36) good anatomical reduction. Finding significant improvement between plate fixation (both types) versus trans-articular screw groups treatment functional outcomes. A clinically crucial improvement in Manchester Oxford Foot & Ankle Questionnaire scores, and improved Euroqol- 5DL outcomes between 4-corner compression plate and trans-articular screw group. Overall, there was no significant difference in metalware failure, metalware removal and soft tissue complications. This study concludes that functional outcomes after Lis Franc fractures are not just dependent on the quality of anatomical reduction but are affected by fixation type. Further studies are required to provide qualitative analysis and assessment of dorsal bridge plate fixation versus 4-corner plate. Significantly, we have seen the 4-corner compression plate group reached the minimum clinically meaningful difference in the Manchester Oxford Foot and Ankle Questionnaire when compared to trans-articular screw fixation.

Midfoot Joint Arthrodesis Using Compression Plate With Lag Screw Augmenting With Highly Porous β-Tricalcium Phosphate and Bone Marrow Aspirate Concentrate

BACKGROUND

There is still a controversy regarding the most optimal fixation instruments and bone graft materials for midfoot joint arthrodesis. We present the results of midfoot joint arthrodesis using compression plate with lag screw augmenting with highly porous β-tricalcium phosphate (β-TCP) and bone marrow aspirate concentrate (BMAC).

METHODS

We performed a retrospective review of patients undergoing midfoot joint arthrodesis using compression plate with lag screw augmenting with highly porous β-TCP and BMAC from January 2014 to May 2019. The radiographic bony union rate was investigated. Postoperative complications and reoperations were also reviewed. A total of 36 patients (37 feet) including 75 joints were available in this study.

RESULTS

A high union rate was achieved as of 97.3% in 73 of 75 joints. Nonunion occurred in 2 patients including 2 joints. Other than nonunion, there were no major complications such as deep infection. Minor complications (5 of 75 joints, 6.7%) included hardware irritations. Reoperations were required in 1 patient for revision of arthrodesis and symptomatic hardware removal was performed in all 5 hardware irritation cases.

CONCLUSION

Based on our results, the fixation construct of compression plate with lag screw augmenting with highly porous β-TCP and BMAC is safe and effective for midfoot joint arthrodesis with an excellent union rate and a low complication rate.

LEVEL OF EVIDENCE

IV, retrospective case series.

Patient-Reported and Radiologic Outcomes With the Lapidus Procedure

Background:

This is a retrospective review of patients who have had a Lapidus procedure for hallux valgus deformity correction, performed by a single surgeon.

Methods:

The clinical records, operation notes and available weightbearing preoperative and postoperative radiographs of all patients who had a Lapidus procedure between February 2008 and July 2018 for hallux valgus deformity were reviewed. The preoperative and postoperative hallux valgus angle (HVA), intermetatarsal angle (IMA), and talometatarsal angle (TMT) on anteroposterior (AP) and lateral radiographs were recorded. The postoperative Foot and Ankle Ability Measure (FAAM) scores were obtained from phone interviews.

Results:

Two hundred thirteen Lapidus procedures were identified between February 2008 and July 2018 and included in the final analysis. The average preoperative and postoperative HVA was 36.3 and 18 degrees, respectively, with an average improvement of 18.3 degrees. The average TMT angles showed a preoperative and postoperative difference of 1.1 degrees on the AP radiograph and 2.4 degrees on the lateral. The average preoperative and postoperative IMA angles were 16.5 and 7.4 degrees, respectively, with an improvement of 9.1 degrees. There were 9 cases (4.2%) of nonunion confirmed on radiography, of which 3 cases (1.4%) had revision fixation with bone graft and went on to radiologic union. Final FAAM scores were available for 151 patients (70.9%). From this group, 74.8% (113/151) scored higher than 90%, 16.6% (25/151) scored between 70% and 90%, and 8.6% scored between 50% and 70%. The patient satisfaction rate was 92.9% overall.

Conclusion:

This single-surgeon retrospective review of a relatively large number of Lapidus procedures reports acceptable radiologic correction and patient satisfaction.

Level of Evidence:

Level IV, Large case series.

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.

Lapidus arthrodesis in combination with arthrodesis of the first metatarsophalangeal joint-biomechanical cadaver study comparing two methods of fixation

AIMS

To assess the results of a biomechanical test of cadaveric specimens, comparing 2 methods of fixation of modified Lapidus arthrodesis in combination with arthrodesis of the first metatarsophalangeal joint.

METHODS

A total of 12 cadaveric specimens were used in the test. Arthrodesis of the first MTP joint was in all patients fixed with a Variable Angle LCP 1st MTP Fusion Plate 2.4/2.7. Two methods of fixation of the Lapidus arthrodesis were compared, i.e. fixation with two screws in the PS (plate-screw) version versus fixation with X-Locking Plate 2.4/2.7 in the PP (plate-plate) version. Measurements were obtained with the use of a testing machine ZWICK Z 020-TND with an optical device Mercury RT for measuring deformities. Each specimen was subjected to 3 loading options, a. displacement 5 mm, the support is placed under the proximal phalanx, b. displacement 5 mm, the support is placed under the first metatarsal head and c. load to failure, the support is placed under the first metatarsal head.

RESULTS

In all specimens the PS construct showed a statistically considerably higher stiffness than the PP construct. In all specimens treated with the PP construct the load to failure was lower than in the PS construct. For loading mode a., at a significance level of 0.05 (P<0.05), the P-value was 0.036, for mode b. the P-value was 0.007 and for loading mode c. the P-value was 0.006. In addition, age-related decrease in stiffness of the specimen was proved at a significance level of 5% (P=0.004).

CONCLUSION

In all the three loading modes, the PS (plate-screw) construct showed a statistically higher stiffness than the PP (plate-plate) construct.

Dorsal bridge plating versus. Transarticular screw fixation for lisfranc injuries: A systematic review and meta-analysis

Lisfranc injuries are relatively uncommon but carry devastating consequences if left untreated. Although many surgical techniques have been proposed for best operative management, there is an ongoing debate over which procedure is superior. We performed a systematic review and meta-analysis comparing the outcomes of transarticular screw fixation and dorsal bridge plating in management of Lisfranc injuries. Ovid MEDLINE, Ovid Embase and Cochrane Central Register of Controlled Trials (CENTRAL) were searched to identify randomised controlled trials (RCTs) and cohort studies comparing the outcomes between screw and dorsal plate fixation. The pooled outcome data were calculated by random and fixed effect models. One prospective cohort and three retrospective studies were identified with a total of 210 patients with mean follow up of 40.6 months. All papers were analysed for quality using the modified Newcastle Ottawa score. The results show that dorsal bridge plating is associated with better American Orthopaedic Foot and Ankle Society score (AOFAS) compared with transarticular screw fixation (OR - 0.71, 95% CI -1.31 to -0.10, p = 0.02). Dorsal plating may also be associated with fewer cases of arthritis, although this was not significant (OR 2.46, 95% CI 0.89 to 6.80, p = 0.08). We found no significant differences between the groups in terms of Foot Function Index (FFI), post traumatic arthritis and failure of hardware material. Although our results suggest dorsal bridge plating may provide superior functional outcomes, there is a scarcity of literature with little robustness to make definitive conclusions. High quality randomised trials are required.

Biomechanical Comparison of First Tarsometatarsal Arthrodesis Constructs Over Prolonged Cyclic Testing

Background:

Traditionally, a lengthy period of nonweightbearing is required following arthrodesis of the first tarsometatarsal (TMT) joint in order to provide a stable healing environment for the bones. The goal of this research was to determine the resistance to plantar gapping of 2 locked intramedullary devices and a medial plate with crossing screw, all specifically designed for hallux valgus correction, and compare them to traditional 2–crossing screw fixation under a cyclic testing protocol. We hypothesized the locked intramedullary devices and the medial plate with crossing screw would better resist plantar gapping.

Methods:

Forty cadaver specimens received 1 of 4 operative treatments: a locked intramedullary device with 2 points of fixation in the cuneiform, a locked intramedullary device with 1 point of fixation in the cuneiform, a medial plate with crossing screw, or 2 crossing screws. We applied dorsiflexion bending forces to the first TMT joint using a cadaveric fatigue model for 20 000 cycles. The plantar gap between the metatarsal and cuneiform was measured at the beginning and end of cyclic testing. Thirty-six specimens were included in the final data set.

Results:

Both locked intramedullary device groups and the medial plate with crossing screw group exhibited significantly less gap widening compared to the 2–crossing screw group (vs 3-hole intramedullary device, P = .014; vs 4-hole intramedullary device, P = .010; and vs medial plate with crossing screw, P = .044). The intramedullary device groups were the most stable during the cyclic fatigue test, exhibiting the smallest gap widening. The medial plate with crossing screw fixation was also more stable than crossing screws in the cyclic fatigue model.

Conclusions:

The locked intramedullary devices and medial plate with crossing screw resisted plantar gapping better than 2 crossing screws when used for first TMT arthrodesis.

Clinical Relevance:

These results indicate that locked intramedullary devices and medial plates with crossing screws may promote superior bone healing and may better tolerate early weightbearing compared with 2 crossing screws.

Neurovascular structures at risk with percutaneous fixation in tarsometatarsal fusion: A cadaveric study

INTRODUCTION

First tarsometatarsal (TMT) joint fusion is routinely used for arthritis and deformities. Common fixation methods include a locking plate construct, cross-screws, or combinations of the two. Cross screws have proven effective for union and stability; however, there is a potential for harm to nearby neurovascular structures due to the nature of percutaneous insertion technique. This study assessed risk of damage to the superficial peroneal nerve with percutaneous TMT fusion.

METHODS

Nine fresh-frozen cadaver specimens were included. A medial incision in the internervous plane was made for TMT joint preparation. Two crossed percutaneous wires followed by 4.0 cc screws were placed in the dorsal aspect of the proximal aspect of first metatarsal and in the medial cuneiform. Both were 10-15 mm from the TMT joint line. The dorsal aspect of the foot was dissected and examined for neurovascular interruptions, particularly branches of the superficial peroneal nerve.

RESULTS

Results showed a mean distance of 4.33 mm from the proximal pin to the medial branch of the superficial peroneal nerve. The distal pin had a mean distance of 6.44 mm from the medial branch, with one pin 9 mm from the lateral branch. One incident of direct injury to the neurovascular bundle was observed.

CONCLUSION

Preparing the joint from the medial side using a percutaneous approach is less invasive, but presents a relative risk for neuritis. Care should be taken during insertion of the percutaneous screw after TMT joint preparation for fusion.

LEVEL OF EVIDENCE

Level V, cadaver study.

Biomechanical comparison of fixation stability using a Lisfranc plate versus transarticular screws

BACKGROUND

To obtain adequate fixation in treating Lisfranc soft tissue injuries, the joint is commonly stabilized using multiple transarticular screws; however iatrogenic injury is a concern. Alternatively, two parallel, longitudinally placed plates, can be used to stabilize the 1st and 2nd tarsometatarsal joints; however this may not provide adequate stability along the Lisfranc ligament. Several biomechanical studies have compared earlier methods of fixation using plates to the standard transarticular screw fixation method, highlighting the potential issue of transverse stability using plates. A novel dorsal plate is introduced, intended to provide transverse and longitudinal stability, without injury to the articular cartilage.

METHODS

A biomechanical cadaver model was developed to compare the fixation stability of a novel Lisfranc plate to that of traditional fixation, using transarticular screws. Thirteen pairs of cadaveric specimens were tested intact, after a simulated Lisfranc injury, and then following implant fixation, using one method of fixation randomly assigned, on either side of each pair. Optical motion tracking was used to measure the motion between each of the following four bones: 1st metatarsal, 2nd metatarsal, 1st cuneiform, and 2nd cuneiform. Testing included both cyclic abduction loading and cyclic axial loading.

RESULTS

Both the Lisfranc plate and screw fixation method provided stability such that the average 3D motions across the Lisfranc joint (between 2nd metatarsal and 1st cuneiform), were between 0.2 and 0.4mm under cyclic abduction loading, and between 0.4 and 0.5mm under cyclic axial loading. Comparing the stability of fixation between the Lisfranc plate and the screws, the differences in motion were all 0.3mm or lower, with no clinically significant differences (p>0.16).

CONCLUSIONS

Diastasis at the Lisfranc joint following fixation with a novel plate or transarticular screw fixation were comparable. Therefore, the Lisfranc plate may provide adequate support without risk of iatrogenic injury to the articular cartilage.

Plate Alone Versus Plate and Lag Screw for Lapidus Arthrodesis: A Biomechanical Comparison of Compression

Background. Arthrodesis of the first tarsal metatarsal joint can be accomplished in many ways. The compressive force attained between various constructs remains unclear. This study compares compression achieved through a locking/compression Lapidus plate both with and without the addition of a lag screw. Methods: A dorsal medial Lapidus/locking compression plate (Total Compression Plate System, OrthoPro, Salt Lake City, UT, now Wright Medical) was applied to one cadaveric limb, while the same plate with the addition of a 4.0-mm cannulated lag screw was applied to the contralateral limb for a total of 5 matched pairs of cadaveric specimens. Compressive force was recorded over time and compared between the constructs using a compression sensor (8" FlexiForce Resistive Force Sensor, Phidgets Inc, Calgary, Alberta, Canada). Results: Compression was maintained for 45.4 minutes in the plate only construct, and 317 minutes with the addition of the lag screw (P = .010). The mean time to 50% peak compression for the plate only construct was 4.90 minutes compared with 15.11 minutes for plate with lag screw construct (P = .012). Conclusion: The addition of a lag screw is recommended for extending the length of compression and possibly reducing nonweightbearing time and the risk of nonunion. Levels of Evidence: Level V.

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.

Functional Outcomes Post Lisfranc Injury-Transarticular Screws, Dorsal Bridge Plating or Combination Treatment?

OBJECTIVE

To identify whether transarticular screws, dorsal bridging plates or a combination of the 2 result in the best functional outcome after Lisfranc injury.

DESIGN

Case series.

SETTING

Level one trauma center.

PATIENTS

Fifty patients who underwent surgical fixation of Lisfranc injuries over a 6-year period were retrospectively reviewed.

INTERVENTION

One of 3 treatment arms: transarticular screw fixation alone, dorsal bridge plating alone or a combination of dorsal bridge and transarticular screw fixation.

MAIN OUTCOME MEASURES

The primary outcome measures were 1 of 2 midfoot scores-the American Orthopaedic Foot and Ankle Society (AOFAS) Midfoot Score and the Foot Function Index (FFI) Score. Secondary results included postoperative complications.

RESULTS

Quality anatomical reduction is the best predictor of functional outcomes (FFI-P = 0.008, AOFAS-P = 0.02). Functional outcomes with both FFI and AOFAS scores were not significantly associated with any of the fixation groups (FFI-P = 0.495, AOFAS-P = 0.654) on univariate analysis. Injury type by Myerson classification systems or open versus closed status was also not significantly associated with any fixation group. Open exposures were more likely to result in soft-tissue complications, but there was no significant difference in metalware failure or need for removal.

CONCLUSION

Functional outcomes after Lisfranc fractures are most dependant on the quality of anatomical reduction and not the choice of fixation implant used.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

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.

Evaluation of Fixation Techniques for Metatarsocuneiform Arthrodesis

First metatarsocuneiform joint arthrodesis has been used in foot and ankle surgery for the treatment of hallux abductovalgus deformity, among other pedal pathologic entities. The goal of the present retrospective study was to compare the fusion rates and complications of an intraplate compression screw fixation, crossing solid core screw fixation, and a single interfragmentary screw with a simple locking plate. All procedures were performed by a single surgeon, and all patients received an identical postoperative protocol. A medical record review was performed of 147 evenly distributed surgical methods. All patients were non-weightbearing by protocol for 4 weeks. The patient covariates included sex, age, nicotine status, osteoporosis, and diabetes. These variables were balanced among the treatment groups and were noncontributory, with the exception of sex. Male patients had a 6 times greater odds of experiencing nonunion. The overall nonunion rate was 6.7%, with 4% symptomatic and requiring revision. The individual nonunion rates for each method were 2% for intraplate compression screw fixation, 5% for single interfragmentary screw with locking plate fixation, and 9% for crossing solid core screw fixation. None of the differences reached statistical significance. The corresponding hardware removal rates were 12%, 11%, and 0%.

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.

The Impact of Nitinol Staples on the Compressive Forces, Contact Area, and Mechanical Properties in Comparison to a Claw Plate and Crossed Screws for the First Tarsometatarsal Arthrodesis

Background The optimal fixation method for the first tarsometatarsal arthrodesis remains controversial. This study aimed to develop a reproducible first tarsometatarsal testing model to evaluate the biomechanical performance of different reconstruction techniques. Methods Crossed screws or a claw plate were compared with a single or double shape memory alloy staple configuration in 20 Sawbones models. Constructs were mechanically tested in 4-point bending to 1, 2, and 3 mm of plantar displacement. The joint contact force and area were measured at time zero, and following 1 and 2 mm of bending. Peak load, stiffness, and plantar gapping were determined. Results Both staple configurations induced a significantly greater contact force and area across the arthrodesis than the crossed screw and claw plate constructs at all measurements. The staple constructs completely recovered their plantar gapping following each test. The claw plate generated the least contact force and area at the joint interface and had significantly greater plantar gapping than all other constructs. The crossed screw constructs were significantly stiffer and had significantly less plantar gapping than the other constructs, but this gapping was not recoverable. Conclusions Crossed screw fixation provides a rigid arthrodesis with limited compression and contact footprint across the joint. Shape memory alloy staples afford dynamic fixation with sustained compression across the arthrodesis. A rigid polyurethane foam model provides an anatomically relevant comparison for evaluating the interface between different fixation techniques. Clinical Relevance The dynamic nature of shape memory alloy staples offers the potential to permit early weight bearing and could be a useful adjunctive device to impart compression across an arthrodesis of the first tarsometatarsal joint.

LEVELS OF EVIDENCE

Therapeutic, Level V: Bench testing.

Inherent Strength of the osteo-WEDGE(™) Bone Plate Locking System for Arthrodesis of the First Metatarsocuneiform Joint: A Biomechanical Study

First metatarsocuneiform joint arthrodesis with a locking bone plate and screw system has been effectively used to correct metatarsus primus varus and instability of the first ray. The goal of the present cadaveric biomechanical study was to quantify and compare the inherent strength of the first metatarsocuneiform joint and surrounding bones fixated with the osteo-WEDGE(™) bone plate locking system (OW) with that of intact specimens. Fourteen fresh-frozen adult human cadaveric foot specimens consisting of the first metatarsal and medial cuneiform bones with intact joint capsules and ligaments were used. The OW was implanted in 7 of these specimens at the first metatarsal cuneiform joint (MCJ), and the remaining 7 specimens were left intact. Each of the specimens was then subjected to axial force to simulate dorsiflexion of the first metatarsal using a cantilever bending test setup. Load was applied on the plantar aspect of the first metatarsal head until failure of the construct. The mean load and bending moment on the first MCJ at failure for the implanted specimens were 119.98 ± 56.76 N and 5.57 ± 2.71 Nm, respectively. For the intact specimens, the mean load and bending moment on the first MCJ at failure were 107.93 ± 60.90 N and 6.07 ± 3.18 Nm, respectively. None of the specimens showed catastrophic failure within the physiologic loading limits. These results imply that the mechanical strength of the OW is comparable to that of intact specimens. Thus, the first MCJ and surrounding bones fixated with an OW should be able to effectively withstand the vertical ground reaction forces the same as intact specimens.

Evaluation of Nitinol Staples for the Lapidus Arthrodesis in a Reproducible Biomechanical Model

While the Lapidus procedure is a widely accepted technique for treatment of hallux valgus, the optimal fixation method to maintain joint stability remains controversial. The purpose of this study is to evaluate the biomechanical properties of new shape memory alloy (SMA) staples arranged in different configurations in a repeatable first tarsometatarsal arthrodesis model. Ten sawbones models of the whole foot (n = 5 per group) were reconstructed using a single dorsal staple or two staples in a delta configuration. Each construct was mechanically tested non-destructively in dorsal four-point bending, medial four-point bending, dorsal three-point bending, and plantar cantilever bending with the staples activated at 37°C. The peak load (newton), stiffness (newton per millimeter), and plantar gapping (millimeter) were determined for each test. Pressure sensors were used to measure the contact force and area of the joint footprint in each group. There was a statistically significant increase in peak load in the two staple constructs compared to the single staple constructs for all testing modalities with P values range from 0.016 to 0.000. Stiffness also increased significantly in all tests except dorsal four-point bending. Pressure sensor readings showed a significantly higher contact force at time zero (P = 0.037) and contact area following loading in the two staple constructs (P = 0.045). Both groups completely recovered any plantar gapping following unloading and restored their initial contact footprint. The biomechanical integrity and repeatability of the models was demonstrated with no construct failures due to hardware or model breakdown. SMA staples provide fixation with the ability to dynamically apply and maintain compression across a simulated arthrodesis following a range of loading conditions.

Biomechanical Comparison of External Fixation and Compression Screws for Transverse Tarsal Joint Arthrodesis

BACKGROUND

Transverse tarsal joint arthrodesis is commonly performed in the operative treatment of hindfoot arthritis and acquired flatfoot deformity. While fixation is typically achieved using screws, failure to obtain and maintain joint compression sometimes occurs, potentially leading to nonunion. External fixation is an alternate method of achieving arthrodesis site compression and has the advantage of allowing postoperative compression adjustment when necessary. However, its performance relative to standard screw fixation has not been quantified in this application. We hypothesized that external fixation could provide transverse tarsal joint compression exceeding that possible with screw fixation.

METHODS

Transverse tarsal joint fixation was performed sequentially, first with a circular external fixator and then with compression screws, on 9 fresh-frozen cadaveric legs. The external fixator was attached in abutting rings fixed to the tibia and the hindfoot and a third anterior ring parallel to the hindfoot ring using transverse wires and half-pins in the tibial diaphysis, calcaneus, and metatarsals. Screw fixation comprised two 4.3 mm headless compression screws traversing the talonavicular joint and 1 across the calcaneocuboid joint. Compressive forces generated during incremental fixator foot ring displacement to 20 mm and incremental screw tightening were measured using a custom-fabricated instrumented miniature external fixator spanning the transverse tarsal joint.

RESULTS

The maximum compressive force generated by the external fixator averaged 186% of that produced by the screws (range, 104%-391%). Fixator compression surpassed that obtainable with screws at 12 mm of ring displacement and decreased when the tibial ring was detached. No correlation was found between bone density and the compressive force achievable by either fusion method.

CONCLUSION

The compression across the transverse tarsal joint that can be obtained with a circular external fixator including a tibial ring exceeds that which can be obtained with 3 headless compression screws. Screw and external fixator performance did not correlate with bone mineral density. This study supports the use of external fixation as an alternative method of generating compression to help stimulate fusion across the transverse tarsal joints.

CLINICAL RELEVANCE

The findings provide biomechanical evidence to support the use of external fixation as a viable option in transverse tarsal joint fusion cases in which screw fixation has failed or is anticipated to be inadequate due to suboptimal bone quality.

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.

The modified Lapidus fusion

Due to its proximal correction site and long lever arm, the Lapidus fusion, modified or not, is a powerful technique to correct hallux valgus deformities. The disadvantages are a high complication rate and a long postoperative rehabilitation period. It is only performed in 5% to 10% of all hallux valgus deformity corrections but remains, however, an important procedure, especially in moderate to severe deformities with intermetatarsal angles more than 14°, hypermobility of the first ray, arthritis of the first tarsometatarsal joint, and recurrent deformities. This article provides an overview of the procedure with special focus on the surgical technique.

Topical review: locking plate technology in foot and ankle surgery

The use of locking plate technology in foot and ankle surgery has increased over the last decade. Reported applications include fracture repair, deformity correction, and arthrodesis. There is limited evidence, however, to guide clinicians with regard to the appropriate and optimal use of this technology. This work aims to examine the current biomechanical and clinical evidence comparing locking construct technology to other forms of fixation in the field of foot and ankle surgery.

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.

New techniques and alternative fixation for the lapidus arthrodesis

Arthrodesis of the first metatarsocuneiform joint is a powerful and durable procedure to help correct moderate to severe hallux valgus and/or first ray hypermobility. However, painful nonunion remains a notoriously high potential outcome. Research regarding locking plates seems promising, and data show lower rates of nonunion. Innovative fixation techniques are new and should be considered in the future as further literature is available on their long-term use. Regardless of the fixation, proper joint preparation and good compression is fundamentally the most important. A case of Lapidus fusion with locking plates after a failed arthrodesis with screws alone is presented.

Biomechanical comparison of a locking plate with intraplate compression screw versus locking plate with plantar interfragmentary screw for Lapidus arthrodesis: a cadaveric study

Lapidus arthrodesis (first metatarsal cuneiform arthrodesis) has become an accepted procedure for hallux abducto valgus. Several variations of fixation have been described. Earlier weightbearing postoperatively has been one reported benefit of using locking plates for fixation. Additionally, studies have demonstrated that fixation placed on the plantar or tension side of the arthrodesis increases the biomechanical advantage. We performed a biomechanical cadaveric study of the Lapidus procedure, comparing a previously reported technique using a low profile locking plate with an intraplate compression screw versus the same locking plate with a plantar interfragmentary screw (PIFS) placed on the tension side of the arthrodesis in 10 fresh, paired, cadaver limbs. The mean ultimate load of the plate with a PIFS was 383.2 ± 211.5 N, and the mean ultimate load of the plate with an intraplate compression screw was 205.5 ± 97.2 N. The mean ultimate load of the LPS Lapidus plate with a PIFS was statistically greater (p = .027) than that with the plate intraplate compression screw. Our results indicated that changing the orientation of the compression screw to a PIFS significantly increased the stability of the Lapidus arthrodesis fixation construct. The modified construct with the PIFS might decrease the incidence of nonunion and, ultimately, allow patients to bear weight faster postoperatively.

Mechanical stability of a locked step-plate versus single compression screw fixation for medial displacement calcaneal osteotomy

BACKGROUND

Reconstruction of a flatfoot commonly involves a calcaneal Medial Displacement Osteotomy (MDO) to correct hindfoot valgus in combination with soft tissue procedures. We compared fixation of an MDO using either a single, large cannulated screw versus a locking step-plate in load to failure in a cadaveric model.

METHODS

Eight matched pairs of cadaveric limbs were loaded using a mechanical testing rig. Two pairs served as non-operated controls. The remaining paired limbs underwent a 10-mm MDO stabilized either with a single 7-mm screw or a step-plate with four locking screws. One pair was used as a pilot study and the remaining five pairs were loaded up to 4500 N to failure.

RESULTS

In the five pairs loaded to failure, the median (with 95% CI) maximum force were 1779 N (1099-2312) and 826 N (288-1607) for the plate and screw, respectively (p = 0.043). With single screw fixation, the tuberosity fragment consistently failed by rotation and angulation into varus. With plate fixation, failure occurred as the screws cut through the internal surfaces of the tuberosity and body with no failure at the screw-plate interface.

CONCLUSION

In this cadaveric model, a locked step-plate supported a significantly higher maximum force than a single large cannulated screw.

CLINICAL RELEVANCE

The magnitude of the load supported by the locking step-plate suggests that allowing early weightbearing post-operation may be safe in clinical practice before union of the osteotomy.

Biomechanical in vitro - stability testing on human specimens of a locking plate system against conventional screw fixation of a proximal first metatarsal lateral displacement osteotomy

INTRODUCTION

The aim of this study was to examine resistance to angulation and displacement of the internal fixation of a proximal first metatarsal lateral displacement osteotomy, using a locking plate system compared with a conventional crossed screw fixation.

MATERIALS AND METHODOLOGY

Seven anatomical human specimens were tested. Each specimen was tested with a locking screw plate as well as a crossed cancellous srew fixation. The statistical analysis was performed by the Friedman test. The level of significance was p = 0.05.

RESULTS

We found larger stability about all three axes of movement analyzed for the PLATE than the crossed screws osteosynthesis (CSO). The Friedman test showed statistical significance at a level of p = 0.05 for all groups and both translational and rotational movements.

CONCLUSION

The results of our study confirm that the fixation of the lateral proximal first metatarsal displacement osteotomy with a locking plate fixation is a technically simple procedure of superior stability.

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

BACKGROUND

Lapidus arthrodesis with a plate and a compression screw is an established procedure in hallux valgus surgery. The present study was performed to investigate the potential benefit of a compression screw combined with a plantarly applied angle-stable, anatomically precontoured plate or a dorsomedially applied angle-stable plate.

METHODS

In six pairs of human cadaver specimens, one specimen each was randomized to receive a dorsomedial H-shaped plate, while the other received a plantar plate. Bone mineral density was measured with peripheral quantitative computed tomography. The specimens were loaded quasi-statically, followed by cyclic loading. Finally, they were loaded to failure. In the static tests, stiffness and range of motion (ROM) data were obtained. In the cyclic tests, the constructs' displacement was studied. In the load-to-failure test, stiffness and maximum load to failure were measured.

RESULTS

The two groups did not differ significantly with regard to BMD (p = 0.25). Any significant differences observed were in favor of the plantar constructs, which had greater initial stiffness (p = 0.028) and final stiffness (p = 0.042), a smaller ROM (p = 0.028), and a greater load to failure (p = 0.043). There was no significant difference regarding displacement (p = 0.14).

CONCLUSION

In the static tests, the plantar angle-stable plate construct was superior to the dorsomedial angle-stable plate construct.

CLINICAL RELEVANCE

Plantar plating appears to offer biomechanical benefit. Clinical studies will be required to show whether this translates into earlier resumption of weightbearing and into lower rates of nonunion.

Opening wedge and anatomic-specific plates in foot and ankle applications

As surgeons continually push to improve techniques and outcomes, anatomic-specific and procedure-specific fixation options are becoming increasingly available. The unique size, shape, and function of the foot provide an ideal framework for the use of anatomic-specific plates. These distinctive plate characteristics range from anatomic contouring and screw placements to incorporated step-offs and wedges. By optimizing support, compression, and stabilization, patients may return to weight bearing and activity sooner, improving outcomes. This article discusses anatomic-specific plates and their use in forefoot and rearfoot surgical procedures.

Locking plate technology and its use in foot and ankle surgery

This article discusses the history of conventional plating, plate biomechanics, and screw function to provide better understanding of osseous physiology and biology using locking plates. The peer-reviewed and non-peer-reviewed literature have been researched to decipher and share the most pertinent information on this topic.

The slot graft technique for foot and ankle arthrodesis in a high-risk patient group

BACKGROUND

High rates of arthrodesis nonunion have been described in the ankle, hindfoot and midfoot in patients with significant risk factors. The purpose of this study was to evaluate fusion rates, risk of reoperation, postoperative pain scores and patient satisfaction for a slot graft inlay arthrodesis technique used in a high-risk group of foot and ankle patients.

MATERIALS AND METHODS

We retrospectively reviewed all ankle, hindfoot and midfoot arthrodeses by two foot and ankle surgeons in our institution between January 2000 and January 2009. Seventeen arthrodesis procedures in 16 patients using the slot graft technique were identified. Patient charts were reviewed for medical history, risk factors, previous surgery and postoperative complications. Time to union was evaluated on radiographs. Patients provided final followup by phone with an assessment of pain, overall satisfaction and use of orthotic or assistive devices.

RESULTS

Union occurred in 13 arthrodesis procedures (77%) with an average time to union of 5 months. Postoperative infection occurred in one patient. Additional surgery was performed in nine patients. At final followup patients reported low pain scores (3 of 10) and high satisfaction (8 of 10). Fourteen of 15 patients contacted indicated that they would choose to undergo the procedure again.

CONCLUSION

The slot graft arthrodesis technique provided satisfactory results in this small group of patients with a low complication rate. Patient satisfaction rates were high with low pain scores at an average of 62 months postoperatively.

Lapidus arthrodesis with a single lag screw and a locking H-plate

The aim of this pilot study was to assess if using an interfragmental lag screw and a Darco(®) locking H-plate for the modified Lapidus arthrodesis in the treatment of hallux abducto valgus deformity (1) would allow for earlier weight bearing than previously described and (2) would indicate whether any changes would occur radiographically with the earlier weight bearing. Twenty-one metatarsocuneiform arthrodeses, in 18 patients, were retrospectively evaluated through chart review and postoperative radiographs. Original diagnoses included painful hallux abducto valgus and osteoarthritis of the first metatarsocuneiform joint. The mean age of the patients was 48 (range, 16 to 70) years. The mean follow-up duration was 38.5 (range, 29 to 60) months. The overall radiographic osseous union rate was 90.5% (19/21 feet), although there were 2 asymptomatic nonunions. There were no cases of fixation failure, and the surgical correction was preserved on follow-up radiographs. Overall, the mean time to full weight bearing was 4.7 (range, 3 to 7.5) weeks, and it was a mean of 8 (range, 7 to 10) weeks before the patient was back to wearing comfortable shoes. The authors concluded that metatarsocuneiform arthrodesis fixated with 1 interfragmentary lag screw and a Darco(®) locking H-plate provides sufficient stability to allow earlier weight bearing than has been previously described with other internal fixation constructs.

Modern techniques in hallux abducto valgus surgery

Hallux abducto valgus surgery is in a constant state of evolution. Innovation is driven by surgeons pursuing the perfect procedure for any clinical scenario. The end point is to eliminate complications and produce satisfied patients. Medical device technology has helped pave the way for some recent advances in bunion surgery. The use of opening base wedge plates, locking plates for the Lapidus fusion, suture endobuttons, and staples for the Akin procedure are the focus in this review of modern techniques.

Fixation of first tarsometatarsal arthrodesis: a retrospective comparative cohort of two techniques

BACKGROUND

Presently, indications for the Lapidus procedure include patients with many pathologies of the first metatarsocuneiform joint. Currently the standard in many areas is that of two or three crossed screws through the first tarsometatarsal region. This type of fixation requires an extended period of nonweightbearing and may be difficult for patient compliance.

MATERIALS AND METHODS

The present study is a retrospective comparison of crossed screw fixation to locking plate fixation without a lag screw on union rates, time to weightbearing, and complications.

RESULTS

One hundred forty-three first TMT fusions met the inclusion criteria. There were 96 fused by crossed screw construct (CS) and 47 by the locked plate with or without compression screw (LP). There was a significant difference in time to full weightbearing and union rate. Time to full weightbearing was 8.8 (range, 3 to 16) weeks and 7.8 (range, 1.5 to 34) weeks in the CS and LP groups, respectively (p < 0.001). Union rate was 89.4% (88 of 96 joints) and 98.5% (46 of 47 joints) in the CS and LP groups, respectively (p < 0.001).

CONCLUSIONS

We found that when using a dorsal-medial locked plate with or without lag screw lead to a superior rate of union compared to standard crossed screw constructs even while allowing earlier return to full weightbearing.

Early weight bearing after modified lapidus arthodesis: a multicenter review of 80 cases

The modified Lapidus arthrodesis involves fusion of the first tarsometatarsal, which typically takes about 6 weeks to consolidate. Postoperative protocols typically involve non-weight bearing until bone consolidation occurs, however, with a stable fixation construct, protected weight bearing can be initiated earlier than 6 weeks into the postoperative period. Studies specifically evaluating an early weight bearing protocol after lapidus arthrodesis do not exist; such a protocol is the focus of this investigation. A multicenter retrospective review of 80 feet in 76 patients who underwent a Lapidus arthrodesis by 2 different surgeons, involving a similar fixation technique and an early weight-bearing protocol, was performed. All patients were allowed protected weight bearing after the first postoperative visit, at approximately 2 weeks into the postoperative course. Patients began protected weight bearing at a mean 14.8 (95% CI 14.0, 15.6) days postoperative. All 80 feet proceeded to successful union (100% union), and the mean time to union was 44.5 days (95% CI 43.0, 46.0). No hardware was broken, and no complications requiring surgical revision were observed before solid boney fusion was achieved. Statistically significant (P < .001) improvements in the first intermetatarsal, hallux abductus, and lateral metatarsal angles were observed; and no cases of pathological first ray elevatus were encountered. The duration of time to bone healing in the cohort described in this article was similar to the rates described in previous reports describing Lapidus arthrodesis managed with a considerably longer duration of initial postoperative non-weight bearing. This study demonstrates that early weight bearing of the Lapidus arthrodesis can be performed without compromising correction or the rate of osseous union. This is the first study that specifically evaluates the early weight bearing protocol after lapidus arthrodesis.

Results of lapidus arthrodesis and locked plating with early weight bearing

In the endeavor toward Lapidus fusion, the authors have studied a new application of locked plating for the first tarsometatarsal joint. The goal was to assess the time to fusion, time to ambulation, rate of delayed union/nonunion, rate of revision, and need for hardware removal following the use of locked-plate technology in the fusion of the first tarsometatarsal joint. The findings denoted an average of 6.95 weeks to radiographic fusion, an average of 2 weeks to ambulation, a 9.52% rate of asymptomatic mal-union, a 0% rate of delayed union or nonunion, and a 0% rate of revision. The rate of need for hardware removal was 4.76%.

Arthrodesis of the first metatarsocuneiform joint: a comparative study of fixation methods

BACKGROUND

The Lapidus bunionectomy is a popular procedure for severe bunion deformity where metatarsus primus varus is equal to or exceeds 15 degrees. We evaluated a new locking compression plate which may improve outcomes with the Lapidus procedure.

METHODS

Ten matched pairs of cadaver feet were used to compare the standard crossed 4.0-mm compression screw method of fixation to the LPS Lapidus plate. After performing the matched operations the cadaver constructs were stressed to failure using the INSTRON and Wavemaker software.

RESULTS

The LPS Lapidus plate load to failure was 108 Nm with a bending moment of 6.0 Nm. The crossed screw technique was inferior at 78 Nm with a bending moment of 4.4 Nm (p = 0.02)

CONCLUSION

Unlike other H-plates or locking plates, load to failure was higher with the Lapidus plate constructs.

CLINICAL RELEVANCE

The increased rigidity provided by these plates may help to minimize the risk of nonunion or malunion.

Lapidus bunionectomy: Early evaluation of crossed lag screws versus locking plate with plantar lag screw

We compared outcomes of the Lapidus bunionectomy fixated with crossed lag screws versus a locking plate with a plantar lag screw. Forty patients who underwent Lapidus bunionectomy between August 2001 and May 2006 were evaluated in a combined retrospective and prospective fashion. Crossed lag screws were used in 19 of the patients, and a locking plate with a plantar lag screw was used in 21 of the patients. Other than fixation, the only interventional difference pertained to postoperative weight bearing, where those receiving the plate initiated full weight bearing on the operated foot at 4 weeks postoperative, as compared to 6 weeks for those receiving crossed screws. Overall, the mean preoperative AOFAS hallux score was 41.75 +/- 2.52, and the postoperative score was 90.48 +/- 8.41 (P < .0001). The overall mean preoperative first intermetatarsal angle was 15.3 degrees +/- 2.32 degrees , and long term the angle was 5.03 degrees +/- 2.86 degrees (P < .0001). When comparisons were made based on the method of fixation, use of an adjunct Akin osteotomy and surgery performed before 2003 were statistically significantly associated with crossed screw fixation, and the preoperative AOFAS score was statistically significantly higher in the locking plate fixation group. There were no statistically significant differences related to postoperative complications between the 2 fixation groups. In conclusion, the Lapidus bunionectomy fixated with a locking plate and a plantar lag screw allows earlier weight bearing in comparison with crossed lag screws, without a difference in complications.

LEVEL OF CLINICAL EVIDENCE

2.

Arthrodesis of the first metatarsocuneiform joint: a comparative cadaveric study of external and internal fixation

Arthrodesis of the first metatarsocuneiform joint for the treatment of severe hallux abductovalgus with or without hypermobility of the first ray has gained popularity in recent years. The purpose of the current study was to compare the strength of external fixation to internal fixation for arthrodesis of the first metatarsocuneiform joint in a cadaveric model. Ten pairs of fresh frozen lower extremity cadaver specimens were used, and randomly assigned to fixation at the first metatarsocuneiform joint with crossed cannulated screws or a monorail uniplanar external fixator. Test specimens were then loaded to failure, which was defined as 3 mm or more of displacement at the arthrodesis site. Because of complications encountered during testing, 4 pairs of specimens were excluded from the final results. In the remaining 12 specimens (6 pairs of cadaver limbs), the mean maximal load to failure was 2300.02 +/- 711.86 N for the external fixator and 1666.38 +/- 1072.75 N for the internal fixation construct, and although this difference was not statistically significant (P = .2557), it was likely to have been clinically significant since approximately 27.55% more force was required to disrupt the external fixation construct in comparison with the internal fixation construct. Given these findings, further research into the mechanical and clinical properties of internal and external fixation for first metatarsocuneiform joint arthrodesis is warranted.

LEVEL OF CLINICAL EVIDENCE

5.