Role of plantar plate and surgical reconstruction techniques on static stability of lesser metatarsophalangeal joints: a biomechanical study

Toes Deformities in Cavovarus: How to Approach Them

Sagittal lesser toe deformities (LTD) are the most common in cavus foot. They are mainly the result of muscular imbalance between intrinsic and extrinsic muscles. Surgery is the second-line treatment if medical treatment fails. The aim of the present study was to provide an update on classification and surgical management of LTD in cavus foot including percutaneous procedures with a special focus on sagittal deformities. Joint sparing procedures are preferred for reducible LTD, whereas lesser toe fusions are used for rigid one in association with tendon transfer or percutaneous procedures depending of surgeon's experience and patient's clinical examination.

Lesser-toe deformity

Lesser-toe deformity is frequent and varied, with severe functional impact. In elderly subjects, it leads to loss of autonomy and increases the risk of falls. The aim of the present study was to provide an update on management, addressing 5 questions. What are the normal anatomy and pathophysiology? These acquired deformities mainly result from imbalance between the intrinsic and extrinsic muscles of the foot or from capsule-ligament stabilizer failure. How to analyze the deformity? It is important to identify the cause, site, reducibility and metatarsophalangeal joint stability. What are the main deformities and how should they be classified? Classifications used to be based on confusing terminology as the deformities were poorly defined. The French Foot Surgery Association (AFCP) therefore validated a classification with standardized, exhaustive and reproducible morphologic descriptions. What treatments are there? Treatment needs to take account of the cause. Footwear adaptation, physiotherapy and podologic measures are in first line, with surgery in second line. Surgery concerns soft tissues (tendon lengthening, tendon transfer, arthrolysis, plantar plate repair), bone (metatarsal and phalangeal osteotomy) and joints (replacement and fusion), with percutaneous and open approaches. What are the treatment strategies? Surgery is performed sequentially, from proximal to distal, if necessary. Options are set out in the decision-trees included in this article. LEVEL OF EVIDENCE: V, expert opinion.

Claw Toe With Dislocated Second Metatarsophalangeal Joint: Treated by Plantar Plate Tenodesis and Release of Collateral Ligaments

Claw toe deformity of the second toe is a common forefoot deformity faced by foot and ankle surgeons. Frequently, it develops as the result of plantar plate insufficiency and subsequent metatarsophalangeal (MTP) joint instability. As the disease deteriorates, the MTP joint can be dislocated. Reduction of the MTP joint without metatarsal osteotomy seems to be a logical approach unless there is excessively long second metatarsal. However, adequate periarticular soft-tissue release including the dorsal capsule, collateral ligaments and extensor tendon is needed to reduce the intra-articular pressure and minimize the risk of joint degeneration. The purpose of this Technical Note is to describe the details of plantar plate tenodesis and release of collateral ligaments for correction of claw second toe associated with dislocation of the metatarsophalangeal joint.

Anatomy: Plantar Plate

The fibrocartilaginous component of the plantar plate offers stability at the metatarsophalangeal joint. In conjunction with the attachments of the deep transverse metatarsal ligaments and collateral ligaments, the plantar plate complex resists tensile forces anchored by the plantar fascia and compression forces under the metatarsal heads.

A Critical Biomechanical Evaluation of Foot and Ankle Soft Tissue Repair

The objective of this article is to review the biomechanical stresses that occur during normal physiologic function of lower extremity soft tissue anatomic structures and to use this as a baseline for a critical analysis of the medical literature because it relates to surgical reconstruction following injury. The Achilles tendon, anterior talofibular ligament, plantar plate, and spring ligament are specifically evaluated.

Operative Management: Plantar Plate

The plantar plate is a vital structure for maintaining lesser metatarsophalangeal joint (MPJ) stability. Its primary role is to provide static stabilization of the MPJs, working in conjunction with the long and short flexor and extensor tendons. When insufficiency or attenuation of the plantar plate occurs, a sagittal plane deformity will slowly develop, eventually leading to a "crossover toe" transverse plane deformity. Coughlin coined this descriptive term to describe the later stages of deformity, most commonly affecting the second MPJ. Shortly after, Yu and Judge elaborated on this condition describing it as "predislocation syndrome," an inflammatory condition affecting the plantar plate causing pain and instability, which could progress to subluxation at the MPJ.

Plantar Plate Repair for Metatarsophalangeal Joint Instability of the Lesser Toes

The plantar plate is a known stabilizer of the lesser toe metatarsophalangeal (MTP) joint. MTP instability is a known common cause of metatarsalgia, most commonly in the second toe. In the last decade, clinical staging and anatomic grading mechanisms have been published to guide the surgeons on the treatment of MTP instability; this has also led to an understanding of how plantar plate tears relate to MTP joint instability. Direct surgical repair of the plantar plate has been described, short-term outcomes have been published, and the results are not perfect, but promising with respect to patient satisfaction and pain relief.

A versatile method for dorsal-approach plantar plate repair using standard operative instruments

Background

The plantar plate is an important static stabilizer of the lesser metatarsophalangeal joints, and disruptions of the plantar plate can lead to significant instability and lesser toe deformities. In recent years, direct plantar plate repair has been proposed. Although direct repair via a dorsal approach is attractive, a torn plantar plate is small and difficult to access using regular instruments in a restricted operative field.

Methods

In this report, a unique method for plantar plate repairs was used to repair various configurations of plantar plate tears with standard operative instruments that are available in most operating rooms.

Results

Using this method, 10 patients underwent plantar plate repairs, and the mean follow-up period was 24 (range, 14–38) months. The mean visual analog scale score for pain preoperatively was 4.1 (range, 0–6) and decreased to 0.6 (range, 0–3) at last follow-up. Postoperatively, the mean visual analog scale score for satisfaction was 9.6 (range, 8–10) and the mean American Orthopedic Foot and Ankle Society forefoot score was 88.8 (range, 75–100).

Conclusions

Our study proposes an inexpensive and versatile method for plantar plate repair via a dorsal approach that uses standard operative instruments.

Trial registration

ClinicalTrials.gov, NCT04949685. July 2, 2021 - Retrospectively registered,

Level of clinical evidence

4

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04951-w.

Transverse laxity of the forefoot

BACKGROUND

Splay of the forefoot reflects the loss of tension in the soft tissues and indicates failure of the biomechanics of the tie-bar system. By identifying and quantifying the soft tissue structures involved in the destruction of forefoot stability we could increase the understanding of forefoot pathologies.

METHODS

We investigated the transverse forefoot laxity on healthy feet, feet with forefoot pathology and cadaveric feet undergoing sequential dissection.

RESULTS

Statistical difference in transverse laxity was seen between healthy feet (n = 160) and feet with symptomatic forefoot pathology requiring surgery (n = 29). Presence of lesser ray pathology is associated with increased transverse laxity. For the dissected cadaveric feet (n = 9) sequential sectioning the plantar plate causes a progressive evolution of transverse laxity. The repair of plantar plates greatly improves transverse stability.

CONCLUSIONS

Forefoot pathology causes increased transverse laxity. In case of a major transverse laxity of the forefoot a plantar plate lesion should be suspected.

Correction of Severe Crossover Toe Deformity By Plantar Plate Tenodesis, Arthroscopic Release of Lumbrical and Plication of Lateral Capsuloligamentous Complex

Plantar plate deficiency is the major cause of instability of the metatarsophalangeal joint, and plantar plate tenodesis can provide dynamic stabilization of the plantar plate. In case of crossover toe deformity, incorporation of arthroscopic release of the medial capsuloligamentous complex and the lumbrical tendon can eliminate the medial deforming force. However, in case of severe deformity, the lateral capsuloligamentous complex is attenuated. The purpose of this Technical Note is to incorporate the technique of arthroscopic plication of the lateral capsuloligamentous complex into the technique of plantar plate tenodesis and arthroscopic release of the medial capsuloligamentous complex and the lumbrical tendon.

Presence of Neovascularization in Torn Plantar Plates of the Lesser Metatarsophalangeal Joints

BACKGROUND

Recent surgical techniques have focused on anatomic repair of lesser toe metatarsophalangeal (MTP) plantar plate tears, yet it remains unknown whether the plantar plate has the biological capacity to heal these repairs. Therefore, a better understanding of the plantar plate vasculature in response to injury may provide further insight into the potential for healing after anatomic plantar plate repair. Recently, a study demonstrated that the microvasculature of the normal plantar plate is densest at the proximal and distal attachments. The purpose of this study was to compare the intact plantar plate microvasculature network to the microvasculature network of plantar plates in the presence of toe deformity using similar perfusion and nano-computed tomographic (CT) imaging methods.

METHODS

Seven fresh-frozen human cadaveric lower extremities with lesser toe deformities including hammertoe or crossover toe were perfused using a barium solution. The soft tissues of each foot were counterstained with phosphomolybdic acid (PMA). Then using nano-CT imaging, the second through fourth toe metatarsophalangeal joints of 7 feet were imaged. These images were then reconstructed, plantar plate tears were identified, and 11 toes remained. The plantar plate microvasculature for these 11 toes was analyzed, and calculation of vascular density along the plantar plate was performed. Using analysis of variance (ANOVA), this experimental group was compared to a control group of 35 toes from cadaveric feet without deformity and the vascular density compared between quartiles of plantar plate length proximal to distal. A power analysis was performed, determining that 11 experimental toes and 35 control toes would be adequate to provide 80% power with an alpha of 0.05.

RESULTS

Significantly greater vascular density (vascular volume/tissue volume) was found along the entire length of the plantar plate for the torn plantar plates compared to intact plantar plates (ANOVA, P < .001). For the first quartile of length (proximal to distal), the vascular density for the torn plantar plates was 0.365 (SD 0.058) compared to 0.281 (SD 0.036) for intact plantar plates; in the second quartile it was 0.300 (SD 0.044) vs 0.175 (SD 0.025); third quartile it was 0.326 (SD 0.051) vs 0.117 (SD 0.015); and fourth (most distal) quartile was 0.600 (SD 0.183) vs 0.319 (SD 0.082).

CONCLUSION

Torn plantar plates showed increased vascular density throughout the length of the plantar plate with an increase in density most notable in the region at or just proximal to the attachment to the proximal phalanx. Our analysis revealed that torn plantar plates exhibit neovascularization around the site of a plantar plate tear that does not exist in normal plantar plates.

CLINICAL RELEVANCE

The clinical significance of the increased vascularity of torn plantar plates is unknown at this time. However, the increase in vasculature may suggest that the plantar plate is a structure that is attempting to heal.

Correction of Crossover Toe Deformity by Plantar Plate Tenodesis and Arthroscopic Release of Lumbrical

Plantar plate deficiency is the major cause of instability of the metatarsophalangeal joint. As the joint subluxates dorsally, the lumbrical is tethered on the medial side of the joint by the deep metatarsal ligament and becomes a deforming force for the development of crossover toe deformity. Release of the lumbrical is needed to achieve adequate medial soft-tissue release. Plantar plate tenodesis has been described to correct the deformity by suturing the plantar plate to the extensor digitorum longus tendon. The purpose of this Technical Note is to incorporate the technique of arthroscopic release of the lumbrical tendon into the technique of plantar plate tenodesis.

A new lesser metatarsophalangeal joint replacement arthroplasty design - in vitro and cadaver studies

Background

Isolated degenerative joint disease and/or Freiberg’s infraction of the lesser metatarsophalangeal joint, although not frequent may become debilitating in the younger individual. Currently, once conservative management fails, the mainstay of treatment is debridement and excision-interposition arthroplasty. Replacement arthroplasty has been ineffective in the long term as the joints are subject to severe repetitive fatigue loading over small articulating surfaces through a wide range of motion. This is an in vitro and cadaver study of a new design replacement arthroplasty developed by the senior author.

The aim of this study is to evaluate this novel replacement arthroplasty of the lesser metatarsophalangeal joint in a laboratory setting and cadaver implantation.

Methods

This three-component mobile bearing device is made of titanium and high density polyethylene which evolved over 4 years. It was subjected to 5,000,000 cycles in a laboratory under physiological and excessive forces to assess resistance to fatigue failure and wear pattern of the polyethylene liner. Following these tests, it was implanted in 15 fresh frozen cadavers at various stages of its development, during which the surgical technique was perfected. Range of motion and stability was tested using custom made instrumentation in four cadavers. The implant was inserted in a further two cadavers by an independent foot and ankle surgeon to check reproducibility.

Results

The device showed almost no signs of wear or surface deformation under physiological forces. The surgical technique was found to be simple and reproducible in the cadaver trial.

The average dorsiflexion was 28.5° and 28.9° pre- and post-implant respectively. The average plantar flexion was 33.8° and 20.8° pre- and post- implant respectively. The joints were stable both pre- and post-operatively. Post-operative stability was objectively assessed for dorsal displacement and dorsiflexion using a 5 kgf (49 N) and was found to be excellent.

Conclusion

This novel lesser metatarsophalangeal joint replacement arthroplasty has been developed as an option in the surgical treatment of symptomatic degenerative joint disease and/or Freiberg’s infraction resistant to conservative treatment. The implant was found to be durable and resistant to wear in the laboratory testing. The cadaver studies have shown it to require minimal specialized instrumentation with good surgical reproducibility.

This proof of concept study is the basis for clinical trials.

One-Year Outcome Study of Anatomic Reconstruction of Lesser Metatarsophalangeal Joints

Background: Lesser metatarsophalangeal joint (MTPJ) and plantar plate pathologies are commonly seen forefoot conditions. Traditional rebalancing techniques are commonly used but can have concerning adverse effects. The purpose of this study was to analyze the 1-year outcomes of a new technique consisting of anatomic repair of the plantar plate and collateral ligaments involving lesser MTPJs. Methodology: A retrospective cohort study of 50 consecutive patients treated with anatomic plantar plate and collateral ligament reconstruction were evaluated for lesser MTPJ imbalances between 2013 and 2016. The primary outcome was postoperative digital stability defined as a normal dorsal drawer test and normal paper pull-out test. Secondary outcomes included pre- and postoperative visual analogue scale pain measurements, MTPJ radiographic alignment, and ACFAS Forefoot module scores. Results: All patients had digital instability prior to the surgical intervention. Final follow-up revealed that 92% of patients showed improved digital stability, P = .0005. Multivariate regression found statistically significant improvement in pain reduction via the visual analogue scale of 51.2 mm (P < .0001) and ACFAS Forefoot module scores improved to 92 (P < .0001). The 45 joints with preoperative abnormal transverse plane deformity, had either complete (n = 29) or partial (n = 16) radiographic MTPJ correction. Conclusion: These results suggest that anatomic repair of lesser MTPJ improved digital stability, pain, function and radiographic alignment with greater than one year of follow-up.Levels of Evidence: Level IV: Retrospective cohort study.

Outcomes Study of an Innovative Method of Direct Repair of Metatarsophalangeal Joint Instability With an Angiocatheter Needle

Plantar plate tears are a common cause of forefoot pain and digital deformity. Repair of the plantar plate has been described from both a dorsal and plantar approach, each with its own benefits and drawbacks. Many of the approaches use costly devices. Our innovative repair method uses low-cost materials available in most operating room settings. We undertook a retrospective case series study to evaluate outcomes in patients who had undergone plantar plate repair with our method of repair. A review was performed to identify patients with plantar plate disruptions treated with this approach by a single surgeon. Clinical position and patient satisfaction of the involved joints were evaluated. Six patients (9 joints) underwent plantar plate repair using this innovative method and were evaluated at a median follow-up time of 19 (range 19 to 39) months. The mean visual analog scale pain score at final follow up was 0.8 ± 2.0. The median sagittal plane position of the toe was 2 mm (range 0 to 6) from the plantar skin of the digit to the ground. Five of the 6 patients (83%) stated that they would have the procedure again. We were able to obtain satisfactory outcomes with good alignment by repairing the plantar plate with this innovative method. Our data suggest that the described method of plantar plate repair can be used as an effective way to treat metatarsal phalangeal joint instability.

Biomechanical Comparison of Low-Profile Contoured Locking Plate With Single Compression Screw to Fully Threaded Compression Screws for First MTP Fusion

BACKGROUND

Open metatarsophalangeal (MTP) arthrodesis using locked plates produces good clinical outcomes. However, arthroscopic fusion with new-generation fully threaded compression screws is emerging as an alternative. The purpose of this study was to compare low-profile contoured locked plates with fully threaded compression screws for first MTP fusion, in a biomechanical cadaveric model.

METHODS

The first rays of 8 matched pairs of fresh frozen cadaveric feet underwent dissection and dual-energy x-ray absorptiometry (DEXA) scanning to measure bone mineral density (BMD). The "plate" group was prepared with cup-and-cone reamers, and fixation of the MTP joint with 1 compression screw and low-profile dorsal locked plate. The matched-pair "screws" group was prepared through a simulated arthroscopic technique, achieving fixation with 2 new-generation fully threaded compression screws. The plantar MTP gap was recorded with an extensometer during 250 000 90-N cyclic loads followed by a single load to failure.

RESULTS

The screw group demonstrated significantly greater stiffness, 31.6 N/mm (plates) and 51.7 N/mm (screws) (P = .0045). There was no significant difference in plantar gapping or load to failure, 198.6 N (plates) and 290.1 N (screws) (P = .2226). Stiffness and load to failure were highly correlated to BMD for the screw group, r =0.79 and r = 0.94, respectively, but less so for the plate group, r = 0.36 and r = 0.62, respectively. The maximum metatarsal head height measured on the lateral view was strongly correlated with load to failure for both the plate- and screw-only groups (r > 0.9).

CONCLUSION

These data demonstrate that hallux MTP arthrodesis utilizing fully threaded compression screws had similar plantar gapping and load to failure when compared with the low-profile locking plate, but with significantly more stiffness. These results support an increased role of fully threaded screws for MTP arthrodesis using either the arthroscopic or open technique. However, with decreased BMD plate fixation may remain the better fixation choice.

CLINICAL RELEVANCE

Our data suggest that with regard to construct stability, fully threaded headless compression screws may be just as effective as low-profile locking plates, but BMD and MTP joint fluoroscopic measurements should be considered in the decision-making process for fixation.

Technique and Tips for Multiplanar Correction of Plantar Plate Repairs in Lesser Metatarsophalangeal Joints

Plantar plate repairs are challenging procedures because of the small anatomy of the plantar plate. This can make them daunting, time-consuming procedures to perform. Advances in technology, such as interference screws and small suture passers, have created improved technique possibilities to decrease difficulty, correct multiple planes of deformity, create stronger constructs, and improve patient results. The plantar plate repair technique presented in this article includes a dorsal approach with a metatarsal osteotomy, a knotless repair that provides a strong construct to allow patients to protectively bear weight immediately, and can reduce operative time by presenting tips to quickly navigate the procedure. The presented technique allows for detailed correction of all three planes of deformity, maximizing patient results.

Plantar Plate Injury and Angular Toe Deformity

Lesser toe plantar plate injuries at the metatarsophalangeal (MTP) joint are a common source of metatarsalgia. The second MTP joint is the most commonly affected digit. The fibrocartilaginous plantar plate is the most important static stabilizer of the MTP joint; high loading with weight bearing can lead to attritional plantar plate injuries. Chronic pain with weight bearing is the common presentation of lesser toe instability. Untreated plantar plate instability can lead to hammer toe and mallet toe deformities. Combined Weil osteotomy and plantar plate repair yields favorable pain relief and angular deformity correction for patients who fail conservative treatment.

Anatomic Reconstruction Versus Traditional Rebalancing in Lesser Metatarsophalangeal Joint Reconstruction

Traditional rebalancing techniques, such as capsulotomies and capsulorrhaphies, are commonly performed during complex hammertoe and lesser metatarsal osteotomy procedures involving metatarsophalangeal joint (MTPJ) contractures; however, floating toes, digital instability, and malalignment are concerns. We critically analyzed the outcomes after anatomic reconstruction of the plantar plate and collateral ligaments compared with those after traditional rebalancing techniques. A case-control study was conducted of 54 patients who had undergone surgical correction of lesser MTPJ imbalances due to complex hammertoe deformities (power 80%, type I error = 0.05). Cases were defined as consecutive patients treated with anatomic plantar plate and collateral ligament reconstruction. Controls had undergone traditional lesser MTPJ rebalancing and were matched to cases by age, gender, follow-up duration (minimum 12 months), and concomitant procedures of the same lesser ray. Multivariate logistic regression demonstrated that patients treated with anatomic reconstruction had greater digital stability (negative dorsal drawer and negative paper pull-out test findings) at final follow-up examination compared with the controls. American College of Foot and Ankle Surgeons (ACFAS) forefoot module scores were greater in the anatomic group in all domains (p ≤ .05). Controls had greater postoperative radiographic MTPJ angles than the cases, with no differences detected between the 2 groups in visual analog scale scores or proximal interphalangeal joint angles. The importance of restoration of the plantar plate and collateral ligament integrity as a digital stabilizer is generally accepted but has not been well studied. We found that anatomic reconstruction yielded greater digital stability, greater ACFAS Forefoot module scores, and better radiographic MTPJ alignment than controls. Additional studies are warranted to assess the long-term viability of anatomic lesser MTPJ reconstruction.

Biomechanical Evaluation of Suture Configurations in Lesser Toe Plantar Plate Repairs

BACKGROUND

Lesser toe metatarsal-phalangeal (MTP) joint instability can be a major source of pain and dysfunction. Instability occurs when there is incompetence of the plantar plate and/or collateral ligaments. Newer operative treatments focus on performing anatomic repairs of the plantar plate. The goal of this study was to compare the biomechanical properties of 3 suture configurations that may be used for plantar plate repairs.

METHODS

Biomechanical analysis of 27 lesser toe plantar plates from fresh frozen human cadavers was completed. The plantar plate was detached from the proximal phalanx, and suture was placed in the distal plantar plate in a horizontal mattress, luggage-tag, or Mason-Allen suture configuration. Cyclic loading followed by load-to-failure testing was performed.

RESULTS

There was a significant difference in peak load-to-failure force between constructs (mattress: 115.53 ± 15.95 N; luggage-tag 102.42 ± 19.33 N; Mason-Allen: 89.96 ± 15.78 N; P = .015). Post hoc analysis demonstrated that the mattress configuration had significantly higher load-to-failure force compared with the Mason-Allen configuration ( P = .004). There were no significant differences between the mattress and the luggage-tag configurations or the luggage-tag and the Mason-Allen configurations. There were no differences in construct stiffness, axial displacement at the time of failure, or number of cycles required to produce 2 mm of displacement.

CONCLUSION

The mattress configuration demonstrated better peak load-to-failure force compared with the Mason-Allen configuration but was not statistically different from the luggage-tag configuration. Although not significant, the mattress configuration trended toward higher load-to-failure force compared with the luggage-tag.

CLINICAL RELEVANCE

The horizontal mattress stitch may be the biomechanically superior configuration in plantar plate repairs.

Treatment of Flexible Lesser Toe Deformities

Lesser toe deformities are among the most common complaints presented to foot and ankle specialists. These deformities present in variable ways, which makes surgical decision making complex. For every type of deformity, there could be a combination of soft tissues and bony procedures, chosen according to the surgeon's preferences. This article first describes modern classification of lesser toe deformities, and then presents the different treatments and procedures available for those flexible deformities. In addition, this article proposes an algorithm based on clinical/radiological evaluation and step-by-step surgical decision making.

Lesser Metatarsophalangeal Joint Instability: Treatment with Tendon Transfers

Complex digital deformities and metatarsophalangeal joint instability encompass a wide range of pathology, and we must identify the different degrees of ligamentous disruption. It is important to address a combination of procedures to treat gross deformities of the lesser toes. Surgical treatment should be individualized and requires a sequential process for adequate reduction and deformity correction. There is no gold standard procedure for every deformity. Although residual stiffness can result from tendon transfer, overall patient satisfaction levels remain high when it is performed under the proper indications and concomitantly with other procedures to gain full correction of these challenging deformities.

Lesser Metatarsophalangeal Joint Instability: Advancements in Plantar Plate Reconstruction

The plantar plate and associated collateral ligaments are the main stabilizers of each of the lesser metatarsophalangeal joints. Although clinical examination and plain radiographs are usually sufficient to establish the diagnosis of a plantar plate tear, MRI or fluoroscopic arthrograms may help in specific cases. Recent results with a dorsal approach to plantar plate repair are promising with respect to pain relief and patient satisfaction.

Radiographic Shape of Foot With Second Metatarsophalangeal Joint Dislocation Associated With Hallux Valgus

BACKGROUND

Second metatarsophalangeal (MTP) joint dislocation is associated with hallux valgus, and the treatment of complete dislocation can be difficult. The purpose of this study was to radiographically clarify the characteristic foot shape in the presence of second MTP joint dislocation.

METHODS

Weight-bearing foot radiographs of the 268 patients (358 feet) with hallux valgus were examined. They were divided into 2 groups: those with second MTP joint dislocation (study group = 179 feet) and those without dislocation (control group = 179 feet). Parameters measured included the hallux valgus angle (HVA), first-second intermetatarsal angle (IMA), second MTP joint angle, hallux interphalangeal angle (IPA), second metatarsal protrusion distance (MPD), metatarsus adductus angle (MAA), and the second metatarsal declination angle (2MDA). Furthermore, the dislocation group was divided into 3 subgroups according to second toe deviation direction: group M (medial type), group N (neutral type), and group L (lateral type).

RESULTS

The IPA and the 2MDA were significantly greater in the study group than in the control group. By multiple comparison analysis, the IMA was greatest in group M and smallest in group L. The IPA was smaller and 2MDA greater in group N than in group L. The HVA and MAA in group L were greatest, and MPD in group L was smallest.

CONCLUSIONS

The patients with second MTP joint dislocation associated with hallux valgus had greater hallux interphalangeal joint varus and a second metatarsal more inclined than with hallux valgus alone. The second toe deviated in a different direction according to the foot shape.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Treatment of postaxial polydactyly with plantar plate and medial collateral ligament reconstruction after supernumerary excision: A case report

Introduction:

Polydactyly is the most common congenital foot anomaly and consists of partial or complete duplication of a toe. Traditionally, surgical treatment has been amputation. There is little evidence when surgical treatment requires repairing the stabilizing structures of the metatarsophalangeal joint

Objective:

Assess the functional and radiologic outcomes of a case of postaxial polydactyly requiring plantar plate plate and medial collateral ligament reconstruction.

Methods:

A 59-year-old female presented at clinic complaining from bilateral fifth toe polydactyly and metatarsalgia. A rudimentary extra toe with bony structures poorly developed was observed in the left foot. An excision was performed on the left foot. In the right foot, a fully developed extra digit was observed with medial and downwards deviation underneath the fourth metatarsal.

Results:

Medial fifth-toe excision, plantar plate repair and medial collateral ligament reconstruction were performed due to malformation and widening of the distal surface of the plantar plate. Patient satisfaction and adequate functional status were observed at one-year follow-up.

Conclusion:

The plantar plate is the principal stabilizer of the MTP joint; therefore its reconstruction is of paramount importance for forefoot biomechanics.

Nonoperative Treatment of a Lesser Toe Plantar Plate Tear with Serial MRI Follow-up: A Case Report

With the current data concentrating on different operative treatment options for plantar plate tears, few data can be found on possible nonoperative treatment strategies for this entity and the specifics of such treatment. In the present case report, the successful nonoperative treatment of a patient with a rupture of the plantar plate in a lesser toe metatarsophalangeal joint is presented. The patient was followed up using repeat clinical examinations and high-resolution magnetic resonance imaging scans for 1 year after the imitation of therapy to provide information on the different stages of the healing process.

Modified double plantar plate tenodesis

BACKGROUND

Metatarsophalangeal joint instability of the lesser toe can cause acquired toe deformity. Plantar plate deficiency is the major pathology. Plantar plate repair can stabilize the joint but may result in iatrogenic transverse plane toe deformity in correction of claw toe deformity. Limited toe extension can be resulted after correction of crossover toe deformity by plantar plate tenodesis and extensor digitorum brevis transfer. A modification of the technique is proposed.

MATERIALS AND METHODS

The clinical outcomes of 10 patients with the modified procedure performed were assessed.

RESULTS

The correction was full in all toes with no recurrence.

CONCLUSION

The modified technique can stabilize the metatarsophalangeal joint and correct lesser toe deformity without the need of tendon transfer, osteotomy or sophisticated instrumentation.

Plantar Plate Repair for Lesser Metatarsophalangeal Joint Instability

BACKGROUND

Lesser metatarsophalangeal (MTP) joint instability is a common cause of forefoot pain. Advances in operative technique and instrumentation have made it possible to anatomically treat plantar plate tears through a dorsal approach. Our goal was to evaluate the subjective, functional, and radiographic outcomes of plantar plate repair (PPR) from a dorsal approach.

METHODS

A prospective case series was performed evaluating the results of PPR in 97 feet with 138 plantar plate tears. Patients underwent PPR from a dorsal approach with a Weil osteotomy. We followed patients at regular intervals for 12 months and collected data preoperatively and postoperatively with respect to visual analog scale (VAS) scores, MTP range of motion (ROM), paper pull-out test, American Orthopaedic Foot & Ankle Society (AOFAS) scores, satisfaction, and radiographic measures.

RESULTS

Eighty percent of patients scored "good" to "excellent" satisfaction scores at 12 months. The mean VAS pain score preoperatively was 5.4/10, and postoperatively was 1.5/10. The mean AOFAS scores increased from 49 to 81 points following surgery. The mean MTP ROM preoperatively was 43 degrees and postoperatively 31 degrees. Forty-two percent of toes passed the paper pull out test prior to surgery and 54% at 12 months. Mean metatarsal shortening was 2.4/3.1/1.2 mm for the second, third, and fourth metatarsals, respectively. The mean MTP joint angles preoperatively were 2/4.9/-1.3 degrees and postoperatively were 7.4/9.6/0.2 degrees, respectively, for the second, third, and fourth MTP joints.

CONCLUSION

We found that the plantar plate could be repaired through a dorsal approach with reliable outcomes. PPR was a viable option to anatomically restore the ligamentous support in the unstable lesser MTP joint.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Plantar Plate Repair Using a Direct Plantar Approach: An Outcomes Analysis

Direct plantar plate repair using a plantar approach has been described previously, but with few reports of the outcomes or clinical results. The purpose of the present study was to determine the outcomes of this technique. We performed a retrospective analysis of patients who had undergone direct plantar plate repair with or without concomitant Weil osteotomy and a prospective patient-reported subjective outcomes analysis. Ultimately, 131 patients (144 toes) were included, and the response rate for the mailed surveys was 53.5% (77 of 144 toes). The clinical outcomes reported a well-aligned toe in 87.1% of cases, with a recurrence rate of 7.6% (11 of 144) and a revision rate of 2.8% (4 of 144). Statistically significant improvement in the overall modified Foot Function Index (p < .001) and subscale scores for pain (p < .001), disability (p < .001), and activity limitation (p = .001) were noted postoperatively compared with the preoperative data. The median postoperative visual analog pain scale level reported at survey completion was 2.0 (range 0.0 to 10.0; mean ± standard deviation 2.3 ± 2.6). Despite the modified Foot Function Index scores, the patient satisfaction questionnaire data reported mixed results. Our modified Foot Function Index results demonstrated that this approach provides excellent postoperative pain relief, improvement of associated disability, and improvement in activity limitations. The importance of managing patient expectations is acknowledged secondary to the discrepancy with the patient satisfaction data and the modified Foot Function Index results. Further prospective study is warranted to compare this technique with alternate dorsal approaches for plantar plate repair with and without associated commercially available suture passing systems.

Correction of Crossover Toe Deformity by Arthroscopically Assisted Plantar Plate Tenodesis

Plantar plate deficiency is the major pathology causing metatarsophalangeal joint instability. As the joint subluxates dorsally, the lumbrical is tethered at the medial side of the joint by the deep metatarsal ligament and becomes a deforming force for the development of crossover toe deformity. Plantar plate repair or reconstruction is a logical surgical treatment option. This can be performed through a dorsal or plantar approach. The purpose of this technical note is to report a minimally invasive technique of crossover toe deformity correction by suturing the plantar plate to the extensor tendon. It is indicated for symptomatic crossover toe deformity that is not responsive to nonsurgical treatment. It is contraindicated if the metatarsophalangeal joint is degenerated, destructed, or dislocated, or there is interdigital neuroma at the sides of the deformed toe, or the deformity is caused by bony deformities of the metatarsal head or the proximal phalanx.

Metatarsophalangeal joint stability: a systematic review on the plantar plate of the lesser toes

Background

Instability of the metatarsophalangeal (MTP) joints of the lesser toes (digiti 2–5) is increasingly being treated by repair of the plantar plate (PP). This systematic review examines the anatomy of the plantar plate of the lesser toes, and the relation between the integrity of the plantar plates of the lesser toes and lesser MTP joint stability.

Methods

The databases of Embase.com, Medline (Ovid), Web of Science, Scopus, Cochrane, Pubmed not medline, Cinahl (ebsco), ProQuest, Lilacs, Scielo and Google Scholar were searched in June 2015 from inception. Studies were included if they were in English, contained primary data, and had a focus on plantar plate anatomy of the lesser toes or on the relationship between integrity of the plantar plate and MTP joint (in)stability. Study characteristics were extracted into two main tables and descriptive anatomical and histological data were summarized into one schematic 3D drawing of the plantar plate.

Results

Nine studies were included in this systematic review, of which five addressed plantar plate anatomy as such and four focused directly and indirectly on plantar plate integrity related to MTP joint stability.

Conclusion

This is the first systematic review regarding plantar plate anatomy related to MTP joint stability of the lesser toes. This review iterates the importance of plantar plate anatomy and integrity for MTP joint stability, and it delineates the lack of primary data regarding plantar plate anatomy of the lesser toes and MTP joint stability.

Electronic supplementary material

The online version of this article (doi:10.1186/s13047-016-0165-2) contains supplementary material, which is available to authorized users.

Tendon Transfers for Management of Digital and Lesser Metatarsophalangeal Joint Deformities

Managing digital and metatarsophalangeal joint (MTPJ) deformities can range from simple to complex and uniplanar to triplanar. Because of the complexity and variability of digital and MTPJ deformities, there are many procedures, and no 1 procedure has become the gold standard. Tendon transfers for digital and MTPJ deformities are just 1 treatment option, and usually they are not stand-alone procedures. Typically, a combination of procedures needs to be performed. This article describes the surgical technique and provides a review of the literature, including clinical results for tendon transfers of the central rays.

Deep transverse metatarsal ligament and static stability of lesser metatarsophalangeal joints: a cadaveric study

BACKGROUND

The static support that guides motion around the lesser metatarsophalangeal joints (MTPJs) is complex. Biomechanical studies revealed important roles of both the plantar plane and collateral ligaments. Since part of the plantar plate is attached to the deep transverse metatarsal ligament (DTML), we hypothesized that the transection of the DTML in the intermetatarsal space may substantially reduce the MTPJ stability.

METHODS

The second, third, and fourth MTPJ stabilities of 6 fresh-frozen human cadaveric foot specimens were measured under load control. Both dorsiflexion and dorsal subluxation conditions were tested. After the intact condition was assessed, the DTML was sequentially transected such that each MTPJ had a unilateral and then a bilateral DTML transection. Stiffness data were calculated using the loading range in each test condition. Paired Student t tests were performed to test for statistical significance (P value less than .05).

RESULTS

In intact specimens, the mean stiffness with dorsiflexion of the second, third, and fourth toes was 0.52 ± 0.15 N/deg. When the DTML was operatively transected on one side, the dorsiflexion stiffness significantly decreased 17.3% to an average of 0.43 ± 1.00 N/deg (P < .001). Subsequent transection of the DTML on the other side of each joint resulted in a further significant decrease of 5.8% to an average of 0.40 ± 0.08 N/deg (P < .001). The mean stiffness with dorsal subluxation of the intact second, third, and fourth toes was 3.55 ± 0.66 N/mm. When the DTML was operatively transected on one side, the dorsal subluxation stiffness significantly decreased 16.1% to an average of 2.98 ± 0.64 N/mm (P < .001). Subsequent transection of the DTML on the other side of each joint resulted in a further significance decrease of 7.6% to an average of 2.71 ± 0.48 N/mm (P = .016).

CONCLUSION

The DTML has a significant role in maintaining lesser MTPJ ligament stability. Both unilateral and bilateral DTML transections caused substantial instability of the lesser MTPJ.

CLINICAL RELEVANCE

The DTML is part of the natural static restraint to dorsiflexion or dorsal subluxation of the lesser MTPJ. Operative transection, injury, or degeneration of this ligament may predispose the adjacent MTPJ to instability.

Small joint arthroscopy in foot and ankle

The clinical application of small joint arthroscopies (metatarsophalangeal joint, Lisfranc joint, Chopart joint, and interphlangeal joint) in the foot has seen significant advancements in the past decades. This article reviews the clinical indications, technical details, outcomes, and potential complications of small joint arthroscopies of the foot.

Dorsal Approach for Plantar Plate Repair With Weil Osteotomy: Operative Technique

In recent years, the role of the plantar plate in lesser metatarsophalangeal joint stability has increasingly been recognized. Tearing or attenuation of the plantar plate often will result in crossover or hammertoe deformity with hyperextension of the MTP joint. Some patients are able to have resolution of painful symptoms with conservative treatment but for those that fail these measures, surgical fixation of the plantar plate is indicated. While, there have been some described techniques for direct repair of the plantar plate, we present a surgical technique through a dorsal approach with a Weil osteotomy which accomplishes great clinical correction of the plantar plate tear and associated toe deformity as well as relief of patient's pain. Additionally, we believe this technique is safe, efficient and reproducible.

LEVEL OF EVIDENCE

Level V, expert opinion.