A Systematic Review of Plantar Plate Repair in the Management of Lesser Metatarsophalangeal Joint Instability

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.

Hammer Toe Correction with Proximal Interphalangeal Joint Arthrodesis

Background

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

Description

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

Alternatives

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

Rationale

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

Expected Outcomes

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

Important Tips

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

Acronyms and Abbreviations

MTP = metatarsophalangealPIP = proximal interphalangeal.

Presurgical Perspective and Postsurgical Evaluation of Plantar Plate and Turf Toe

Capsuloligamentous injury of the first metatarsophalangeal (MTP) joint (eponymously called "turf toe") mostly occurs in athletes and involves acute trauma, whereas tears of the lesser MTP joint plantar plate typically are an attritional-degenerative condition. This article reviews the anatomy, pathophysiology, mechanism and patterns of injury, grading and classification of injury, imaging appearances (pre- and postoperative), and management of first MTP joint capsuloligamentous injuries and lesser MTP joint plantar plate tears. These two distinct pathologies are discussed in separate sections.

Direct Plantar Approach to Plantar Plate Repair and Associated Wound Complications

BACKGROUND

Lesser toe metatarsophalangeal joint (MTPJ) instability, secondary to plantar plate tear, has been the focus of numerous recent publications, the majority reporting on repair through a dorsal approach. A plantar approach has been described with the advantage of direct ligamentous repair or repair to bone, which follows conventional techniques employed throughout the body. Previous clinical studies have shown success in deformity correction and the longevity of both approaches. The proponents of the dorsal approach advocate that indirect repair of the plantar plate avoids perceived risks of complications with a plantar incision without evidence of superior outcomes. The purpose of this study was to investigate the safety and efficacy of the direct plantar approach to plantar plate repairs (PPRs) by reporting the rate of specific complications in a large clinical series.

METHODS

This was the institutional review board (IRB) approved retrospective study of 204 PPRs in 185 patients (194 lesser MTP, 10 hallux MTP) with an average age of 56 and a mean body mass index (BMI) of 28. Surgical technique involved repair with absorbable braided suture (88%) versus suture anchor (12%) with or without MTPJ pinning (80%). Mean follow up was 53 weeks (range 5-170). Patients were screened for associated risk factors, including diabetes mellitus (8%), tobacco use (5%), neuropathy (1%), and additional concurrent procedures (96%). Complications were defined as superficial or deep infection, painful scars, and reoperation. Analysis was conducted using the Wilcoxon-Mann-Whitney test or Fisher's exact tests for continuous and categorical variables, respectively. Risk factors were analyzed using univariate logistic analysis to produce odds ratios (OR) with a 95% confidence interval (CI) and an inclusion criterion of a P-value, P > .2 for multivariate analysis as determined by Wald tests (significance at P < .05 for final modeling).

RESULTS

Overall, there were 31 total complications (15%) demonstrated by 14 superficial infections (6.8%) and 17 painful scars (8.3%) along with three reoperations (1.4%). All reoperations were performed for deformity or instability, not scar revision. There were no deep infections. No increased odds of complications were found with suture anchor repair, MTPJ pinning, neuropathy, or diabetes. Patients that used tobacco had 7.5 (CI 1.66, 34.06) the odds of developing any wound complication compared with nonsmokers. Tobacco use was also found to significantly increase the odds of superficial infection by 9.8 (CI 2.08, 46.15). There was no increase in painful scars or reoperation in tobacco users. This study did not find an increased complication rate with additional ipsilateral procedures performed at the time of surgery.

CONCLUSION

To our knowledge, this is the largest study evaluating the direct plantar approach to PPR as well as the evaluation of associated complications with the plantar incision. With low complication and minimal reoperation rates, the results of this study have demonstrated the clinical viability of plantar-based incisions. Previous studies have demonstrated the success of PPR and correction of deformity with a direct approach. This case series further demonstrates the safety and efficacy of plantar-based incisions, particularly for direct PPRs.

LEVEL OF EVIDENCE

IV Retrospective Case Series.

CATEGORY

Lesser Toes.

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.

Treatment of Lesser Metatarsophalangeal Joint Instability With Plantar Plate Repair: A Systematic Review and Meta-Analysis

Recognition of metatarsophalangeal joint plantar plate injuries has improved over time as the condition has become more widely understood and identified. With the diagnosis of a plantar plate injury as a subset of metatarsalgia becoming more common place, there are multiple surgical options that have been utilized to address the condition. Direct repair of the plantar plate has emerged as the treatment of choice for foot surgeons with a tendency to favor a direct dorsal approach for the repair. We performed a systematic review and meta-analysis using preferred reporting items for systematic reviews and meta-analysis guidelines, to determine the magnitude of change that can be expected in visual analog scale pain and American Orthopedic Foot and Ankle Society scores postoperatively. A total of 12 studies involving 537 plantar plate tears were included who underwent direct repair of the plantar plate through either a dorsal (10 articles) or plantar approach (2 articles). Summary estimates were calculated which revealed improvement in visual analog scale pain (pooled mean change of -5.01 [95%CI -5.36, -4.66] pre-to postoperative) and improvement in American Orthopedic Foot and Ankle Society scores (pooled postoperative mean improvement 40.44 [95%CI 37.90, 42.97]) of patients within the included studies. Random effects models were used for summary estimates. I² statistic was used to assess for heterogeneity. We concluded there is a predictable level of improvement in pain and function in patients undergoing a direct dorsal approach plantar plate repair with follow-up out to 2 years.

Podoscopic classification of second toe deformities

BACKGROUND

The AFCP (French Association of Foot Surgery) classification was recently introduced as a reliable and quick visual method for the assessment of sagittal plane deformities of the second toe. The aim of this study was four-fold: (1) to describe a new toe-ground area score (TAS) as an additional dynamic tool of such classification, (2) to verify whether all second toe deformities could be classified, (3) to assess the TAS intra- and inter-observer reliability and (4) to evaluate the TAS learning curve.

METHODS

In this retrospective study 52 s toes were evaluated using a podoscope. Ten foot and ankle surgeons assessed independently standardised videos of each case acquired in a blinded fashion. Assessment was repeated three times, 15 days apart. Intra- (Intraclass Correlation Coefficient or ICC) and inter-observer reliability (Fleiss' Kappa coefficient) were calculated. Mean time to assess a deformity was also recorded.

RESULTS

All the 522 observations (52 feet assessed by 10 surgeons) were successfully rated using the TAS. Intra- and inter-observer reliability were substantial for the first round (ICC: 0.79; Kappa: 0.76) and excellent for the second (ICC: 0.88; Kappa: 0.8) and third round (ICC: 0.84; Kappa: 0.81). Mean assessment time ± standard deviation was 22 ± 11 s per case for the last two rounds.

CONCLUSIONS

The TAS has been proven reliable and quick in the assessment of second toe deformities. When combined with a static segmentary classification of the toe (such as the AFCP classification) it might provide further dynamic informations about the ability of the toe to engage the ground.

LEVEL OF EVIDENCE

Level IV, retrospective cohort study.

The biomechanical characteristics of a feline distal forelimb: A finite element analysis study

As a typical digitigrade mammal, the uniquely designed small distal limbs of the feline support two to three times of its body weight during daily movements. To understand how force transmission occurs in relation to the distal joint in a feline limb, which transfers bodyweight to the ground, it is necessary to examine the internal stress distribution of the distal joint limb in detail. Therefore, finite element models (FEM) of a healthy feline were established to predict the internal stress distribution of the distal limb. The FEM model included 23 bony components, various cartilaginous ligaments, as well as the encapsulated soft tissue of the paw. The FEM model was validated by comparison of paw pressure distribution, obtained from an experiment for balance standing. The results demonstrated a good agreement between the experimentally measured and numerically predicted pressure distribution in the feline paw. Additionally, higher stress levels were noted in the metacarpal segment, with smaller stresses observed in the phalanges portion including the proximal, middle, and distal segments. The raised metacarpal segment plays an important role in creating a stiff junction between the metacarpophalangeal (MCP) and wrist joint, stabilizing the distal limb. The paw pads help to optimize stress distribution in phalanx region. Findings from this study contribute to our understanding of feline distal forelimb biomechanical behavior. This information can be applied to bionic design of footwear since an optimal stiff junction and pressure distribution can be adapted to enhance injury relief and sports activities. Further developments may include progress, evaluation, and treatment of metatarsophalangeal joint injuries in human populations.

Impact of crossover second toe on the postoperative outcome of distal chevron osteotomy for moderate to severe hallux valgus

BACKGROUND

Crossover second toe is often presented in moderate to severe hallux valgus. However, its clinical impact on the postoperative outcome of hallux valgus is still unknown.

METHODS

Thirty-five patients who had moderate to severe hallux valgus with crossover second toe were matched with 35 controls who did not have crossover second toe, according to preoperative hallux valgus angle and first-second intermetatarsal angle. Radiological parameters, Foot Function Index (FFI), and Visual Analog Scale (VAS) were assessed as postoperative outcomes at 3, 6, and 12 months after surgery.

RESULTS

At 3 months, the FFI in the crossover second toe group was lower than in the control group (p=0.001), while other outcomes were similar. On the other hand, there were no significant differences between the groups at 6 and 12 months, in terms of radiological parameters, FFI, and VAS.

CONCLUSIONS

Patients who had moderate to severe hallux valgus with crossover second toe were at risk for slow functional recovery after surgical treatment in the short term, but, in the long-term, there was no difference in overall postoperative outcomes in patients with and without crossover second toe.

LEVEL OF EVIDENCE

Level III, retrospective comparative 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.