Lesser Metatarsal-Phalangeal Joint Pathology PDF

Lesser MetatarsalPhalangeal Joint Pathology MATHEW JOHNSTONE DPM ASSISTANT PROFESSOR CPM DES MOINES UNIVERSITY u This presentation may contain copyrighted Copyright notice material used for educational purposes under the guidelines of Fair Use and the TEACH Act. It is intended only for use by studen...

Lesser MetatarsalPhalangeal Joint Pathology MATHEW JOHNSTONE DPM ASSISTANT PROFESSOR CPM DES MOINES UNIVERSITY u This presentation may contain copyrighted Copyright notice material used for educational purposes under the guidelines of Fair Use and the TEACH Act. It is intended only for use by students enrolled in this course. Reproduction or distribution is prohibited. Unauthorized use is a violation of the DMU Integrity Code and may also violate federal copyright protection laws. Learning Objectives 1 Demonstrate knowledge of etiology and imaging options for pathology of lesser metatarsophalangeal joint (MTPJ) pathology 2 Demonstrate knowledge of conservative treatment of lesser MTPJ pathology 3 Demonstrate knowledge of surgical management of lesser MTPJ pathology Lecture overview u Anatomical review u Functional anatomy of the MTPJ u List of common pathologies affecting the MTPJ u Surgical techniques for selected conditions (approach/dissection will be similar) Anatomical review MTPJ Structure u The MTPJ is a condyloid, synovial type joint u Allows motion in primarily two planes u Joint capsule contains synovial fluid and is bordered by articular cartilage of the proximal phalangeal base and metatarsal head Normal radiographic anatomy: X-ray u What are we looking for in this image? u Shape of the metatarsal head u Space of the MTPJ u Compare this to adjacent toes and contralateral foot u Angulation of the toes u Erosions of the bone? u Subluxation or dislocation of the toe. u Any incidental findings u This otherwise-normal foot has a fifth MTPJ sesamoid Anatomical review: Ligamentous anatomy u Each MTPJ is supported by the joint capsule itself as well as: u Proper and accessory collateral ligaments u Plantar ligament u Deep transverse intermetatarsal ligament Ligamentous anatomy: Normal MRI Imaging u The annotated cross-sectional anatomy above is paired with an MRI coronal image u Note the location of the N/v bundle (NVB) deep to the DTIML u Note u Red Asterix: Proper collateral ligaments u Red Arrows: Accessory collateral ligaments u Blue arrows: plantar ligament Ligamentous anatomy: Normal MRI Imaging u A sagittal plane view is seen to the right with locations of the proper collateral ligament (PCL), accessory collateral ligament (ACL) and plantar plate (PP) shown diagrammatically. u Note how the PCL and ACL are not visualized on the sagittal MRI, however you CAN appreciate the intact plantar plate (PP) Ligamentous anatomy: Normal MRI Imaging ON THE AXIAL MRI, THE PAIR OF COLLATERAL LIGAMENTS CAN BE SEEN TO EXTEND AND INSERT ON THE BASE OF THE PROXIMAL PHALANX. Tendinous anatomy: lesser MTPJ u Each lesser MTPJ is crossed by: u The long Flexor tendon (FDL) u The Short Flexor Tendon (FDB) u The Long Extensor tendon (EDL) u The Short extensor Tendon (EDB) u 2 interosseous muscles u u Counting flexor digiti quinti brevis 1 lumbrical muscle Coronal MRI: tendinous anatomy Sagittal plane T1 MRI with flexor tendons Functional anatomy: The Extensor Tendons u The EDL and EDB insert upon the distal phalanx and middle phalanx respectively u However, the bulk of their dorsiflexory force is directed through the extensor sling leading to dorsiflexion at the MTPJ primarily Functional anatomy: The flexor tendons u There is no single tendon which is ideally positioned to oppose the Extensor complex’s ability to dorsiflex the MTPJ u Reference the biomechanical diagram below u During push-off the moment of force surrounding the MTPJ is generated by the ground reactive force (GRF) and the length of the toe (lever arm (R)) u This must be opposed by the force of the flexor tendon (F-flexor) (operating around the much shorter moment-arm (r) Functional anatomy: The flexor tendons as a deforming force u With their insertions on the distal and middle phalanx the long and short flexor tendons exert a plantarflexion primarily at the PIPJ and DIPJ (not the MTPJ) u When the MTPJ is dorsiflexed (or dislocated as shown), these tendons are placed under stretch, plantarflexing the DIPJ and PIPJ which can increase the appearance of claw toes Functional anatomy: interossei Interosseus muscle Lumbrical u Think of the interossei (dorsal and plantar) as a pair of muscles positioned on either side of the metatarsal u These insert on the plantar aspect of the base of the proximal phalanx u In stance these function to stabilize and plantarflex the MTPJ (if both function in unison) Functional anatomy: the lumbricals u The lumbricals may be small, however their position, origin and insertion aids greatly in stabilizing the digit u Inserts upon the proximal phalanx and extensor hood providing a plantarflexory force at the MTPJ u Because it originates from the flexor tendons, the pull of the lumbrical slacks the distal insertions of the flexors, opposing their tendency to plantarflex the PIPJ and DIPJ MTPJ pathology u Several pathologies specific to the lesser MTPJ can be associated with Forefoot pain, many of which tie in with mechanical imbalance u Capsulitis u Predislocation syndrome u Plantar plate injury u Degenerative arthritis u Avascular necrosis/ Freiberg’s Predislocation Syndrome u “Progressive, painful subluxation or dislocation of the proximal phalangeal base on the metatarsal head”- Gerard Yu et al 2002 u Weakening of the peri-articular tissues/plantar plate u 2002 articles described 3 stages (following slides) u Can be slow-onset or acute/ rapidly progressive u Can affect any lesser MTPJ u May present with a hammertoe, although this is not the causative factor. Predislocation syndrome stage I u Subtle, mild edema dorsal and plantar to lesser MPJ u Exquisite tenderness plantar and distal to joint (red circle) u Alignment of the digit clinically and radiographically appears unchanged compared to contralateral digit Predislocation syndrome stage II u Moderate Edema u Noticeable deviation of the digit both clinically and radiographically u Loss of toe purchase, noticeable in weight bearing Predislocation syndrome stage III u Moderate edema u Clinically, the deviation (subluxation or dislocation) is more pronounced u Subluxation or dislocation radiographically CLINICAL TESTING FOR PDS: DIGITAL LACHMAN'S TEST u Place your fingers on the toe being tested while stabilizing the head of the metatarsal u Keep the toe parallel to the plantar aspect of the foot u Test for dorsal translocation (dorsal drawer) u Easy to confuse dorsiflexion for translocation, keep toe parallel u Compare to the contralateral side Digital Lachman’s test u Images to the right demonstrate dorsal translocation of the digit u Not to be confused with dorsiflexion u Note the continued parallel orientation of the phalanx and “straight up” direction of the pull of the examiner PREDISLOCATION SYNDROME: IMAGING u Initial radiographs often appear negative as on the left u Note the splayfoot deformity u Increased pressure on lesser MTPJ? u Later stages show a progressive angulation of the affected digit and eventual discoloration (right) Conservative treatment of PDS u Conservative treatment u Metatarsal pads u Budin splint u Cross over taping u NSAIDs u Ice u Stiff soled shoes u CAM boot Surgical treatment of PDS: Plantar plate tears u A feature of late-stage Predislocation syndrome u Can also occur traumatically u Partial or complete rupture of the plantar plate Anatomy of the MTPJ plantar plate u A glenoid (shallow cavity) fibrocartilaginous structure situated directly plantar to the metatarsal head. u The plantar fascia and deep transverse intermetatarsal ligaments insert here Plantar plate tear Imaging Plain film usually nondiagnostic, although late stage PDS will show subluxation of the MTPJ Sometimes a diagnosis of exclusion as other similarappearing conditions ruled out. Ultrasound (shown) may be useful in determining plantar plate tears dynamically This requires an experienced U/S provider Nuclear medicine (Tc-99 scan) u Blood pool phase will often be positive for radiotracer uptake (Left images) u Delayed phase will be negative (right images) u This can help to distinguish soft tissue injury like plantar plate tear from bone pathology. Coronal MRI appearance u On the coronal MRI it may be more difficult to visualize the extent of the tear Flexor tendon with edema Plantar plate Lateral aspect of plate of 2nd MPJ Disrupted with edema Sagittal MRI appearance Plantar plate Disrupted distally With edema u Recall that MRIs are taken in “slices” which often measure thicker than the width of the injury u MRI evaluation may miss a true rupture, use clinical suspicion for ordering further tests as needed. Articular cartilage Flexor tendon With edema Arthrogram 0.5-1mL of iodinated contrast injected into joint under fluoroscopy Contrast tracking into the tendon sheath indicated PP tear/ rupture. (top left) this is diagnostic (best test) Plantar Plate Repair u Surgical treatment u Direct repair (plantar or dorsal approach) u Indirect stabilization u Flexor tendon transfer u PIPJ fusion often done with above procedures to enhance stabilization u May also need to do metatarsal osteotomy if metatarsal is long u Limited studies done on 2nd MPJ fusion Let's repair a plantar plate u The plantar plate is most easily approached through a plantar incision. u Photos shown u Complications? u The next few slides with detail the dorsal approach The dorsal approach (sawbones) u The incision is made overlying the interspace or directly over the injured MTPJ u Incision can be extended to the PIPJ level if a hammertoe repair is also planned. The dorsal approach (sawbones) u The digit is plantarflexed to allow access to the plantar joint capsule and plantar plate. The dorsal approach (sawbones) u A McGlamery elevator (seen below) is introduced into the joint plantarly to free the proximal plantar plate attachments. The dorsal approach (sawbones) u An oblique shortening osteotomy is performed in the affected metatarsal head to obtain better access to the injured plantar plate u A graduated “pusher” can be used to track the depth of translation. The dorsal approach (sawbones) u The metatarsal osteotomy is temporarily fixated with a K wire u A few MM of the dorsal flare can be trimmed to allow even better visualization. u The dorsal approach (sawbones) A miniature Hinterman type jointdistractor is applied over the first temporary fixation wire and used to align and drive a second wire into the base of the proximal phalanx u The apparatus is then used to easily distract the joint for maximum visualization The dorsal approach (sawbones) u The plantar plate Is released fully from the distal attachment. u It probably was not in good shape anyways u Otherwise, you would not be here repairing it. The dorsal approach (sawbones) u A specialized suture-passer is used to place a horizontal mattress suture into the torn plantar plate. The dorsal approach (sawbones) u The retractor is removed u A pair of drill-holes are placed into the base of the proximal phalanx. The dorsal approach (sawbones) u A wire-loop suture passer is placed dorsally through one of those drill holes that you just made The dorsal approach (sawbones) u Put the suture into the wire loop, then pull the wire-loop back out through the drill hole, bringing the suture with you u Do this with both ends seen below The dorsal approach (sawbones) DON’T FORGET TO PUT THE METATARSAL HEAD BACK IN PLACE! The dorsal approach (sawbones) u Pull on the sutures to relocate the toe and re- approximate the plantar plate u Tie off the sutures dorsally right against the bone of the proximal phalanx. u This should eliminate the dorsal drawer sign Postoperative care: plantar plate repair u Gauze and tape-splint dressings to help hold the toe in position u Partial WB in postop shoe or CAM boot (avoid WB through the repair site) u ROM begins when pain is controlled enough to start moving the joint u ~10 days: start active ROM exercises u Roomy shoes after surgery, counsel patients that swelling and stiffness are common following repair. First metatarsal-phalangeal joint dislocation Traumatic dislocations of the MTPJ More common than lesser MTPJ Jahss classification system (1980) Lesser MTPJ dislocation Rare Conservative treatment following successful closed-reduction mirrors plantar plate rupture or PDS May need to be surgically reduced for recurrent dislocations First MTPJ dislocations u Similar mechanism of injury to “turf toe” (plantar plate rupture) u MTPJ is visibly dislocated on radiographs u Sesamoids may present with or without fractures! Jahss classification u Approach to first MTPJ dislocation based on presentation u Type I: dislocation with sesamoids and sesamoidal ligament intact u Type 2A: Inter-sesamoid Sesamoid ligament rupture u Type 2B: Sesamoid fracture with partially ruptured inter-sesamoidal ligament u Type 2C: (added by Copeland and Kanat), one or both sesamoids fractured with complete intersesamoidal ligament rupture Jahss type I Open reduction is REQUIRED Treatment of First MTPJ dislocation Jahss: ANY OTHER TYPE Attempt closed reduction Move on to open reduction if closed reduction fails/ is impossible Let's do: An open first MTPJ reduction u Plan your incision overlying the first MTPJ u This will mirror a bunionectomy incision u Adequate exposure of the joint is necessary as you will need access to the plantar structures. Let's do: An open first MTPJ reduction DISSECT IN LAYERS UNTIL THE FIRST MTPJ IS EXPOSED Let's do: An open first MTPJ reduction MAKE NOTE THAT THE SESAMOIDS WILL BE DORSALLY DISLOCATED AS WELL Let's do: An open first MTPJ reduction u Reduce the sesamoid complex with traction (pulling on the great toe) u You may need to place a retractor plantar to the joint in order to gain leverage Let's do: An open first MTPJ reduction u Check your work! u Make sure that the sesamoid complex is appropriately reduced by taking radiographs u Don’t forget that sesamoid axial Capsulitis/Synovitis u Capsulitis: Inflammation of the joint capsule or supporting ligaments u Synovitis: inflammation of the synovial membrane of the joint u u Often with increase fluid within the joint capsule Presentation: u Pain and swelling about the forefoot centered over one of the MTPJs u Redness (check plantar skin as well) u Patient may report “walking on a rock” or ball u Difficulty wearing shoes. Capsulitis/Synovitis clinical exam u Similar clinical presentation and location of pain to PDS/ plantar plate tear u Negative digital Lachman’s test u May have tenderness with passive toe ROM u Associations u Insufficient first ray u Equinus u Inflammatory arthropathies Capsulitis/ synovitis: Plain film u Often will appear normal u Inflammatory arthropathies like RA (pictured below) can show peri-articular erosions of the bones. u MTPJ arthrogram will be negative for fluid- extravasation. Capsulitis/ synovitis: MRI evaluation u T2 weighted image will show joint effusion (fluid) around the joint. u The bottom image is of a plantar plate rupture (red arrow) with synovitis (dorsal fluid shown with blue arrow) Degenerative Arthropathies u The peri-articular erosions of Rheumatoid arthritis feature on a previous slide (RA will be its own lecture) u The next few slides will serve as a brief overview of clinical and radiographic features of seronegative arthropathies u Psoriatic arthritis is the classic example, reactive arthritis, neuropathic arthropathy and ankylosing spondylitis can appear in similar fashions radiographically Clinical features Peripheral Joint pain (inflammatory) with associated stiffness of more than 1 hour Often associated with chronic lower back pain (often prior to age 45) Stiffness responds to increased activity Swelling of the digits (dactylitis) NSAIDs may markedly reduce pain History of rash or nail changes Psoriatic Arthritis u There is no lab test which is diagnostic for this condition u May or may not present with Psoriatic plaque on the skin u Often presents with nail changes (pitting, salmon spots) u Dactylitis of the digits (shown) is a classic clinical finding u Must be distinguished from infection Clinical findings associated with PA u up to 70% of PA patients have nail psoriasis depending on study, with skin/nail pathology preceding PA in 80% of those patients u Pitting and partial onycholysis seen top u Salmon-colored patch of the nail bed seen bottom Psoriatic arthritis at the MTPJ u Joint degenerations in the early stages may be nonspecific u Late-stage erosions lead to the “pencil in cup” appearance of osteoarthritis mutilans u This term is also applied to neuropathic arthropathy and reactive arthropathy Associated radiographic features of PA u Symmetrical peri-articular erosions o the DIPJ forming a “gull wing pattern” Freiberg’s infarction Essentially AVN of the second metatarsal head Can affect any metatarsal Most commonly the second Presents in similar fashion to other forefoot pathology Pain Swelling (localized) Tenderness with WB, less with rest May present with progressive dislocation of toe. Freiberg’s infarction: Clinical history u Most common in female patients aged 13-18 although not limited to this age. u Women>>Men 4:1 u Most commonly in the second metatarsal u Associated with elongated second metatarsal Workup u Radiographic workup (staging) u Smille’s Staging system is used to determine level of treatment u Staging is based on changes to the metatarsal head Following slides show in detail what radiographs reflect of the changes. u Initial Smillie Classification is based on intraoperative findings (system dates to 1967) Freibergs staging STAGE 1 DESCRIBES A FRACTURE THROUGH THE EPIPHYSIS AND IS OFTEN NORMAL ON PLAIN FILM. Freibergs staging STAGE 2 DESCRIBES A “SINKING OF THE ARTICULAR SURFACE” ON THE PROXIMAL SIDE OF THE JOINT, MAY SEE A DORSAL COLLAPSE OF THE ROUNDED METATARSAL HEAD SHAPE Freibergs staging STAGE 3 DESCRIBES FURTHER SINKING WITH PROJECTION OF THE METATARSAL HEAD MEDIALLY AND LATERALLY, THE ARTICULAR CARTILAGE REMAINS INTACT Freibergs staging STAGE 4 MARKS THE LOSS OF THE ARTICULAR SURFACE WITH LOOSE BODY, POSSIBLE FRACTURE OF THE MEDIAL AND LATERAL MET HEAD PROJECTIONS, AND LOSS OF JOINT SPACE STAGE 4 AND BEYOND CANNOT BE TREATED WITH “JOINT SPARING” SURGERY Freibergs staging STAGE 5: OBLITERATION OF THE JOINT SPACE WITH METATARSAL HEAD FLATTENING AND DEGENERATION OF THE MET HEAD. u Initial radiographs (stage 0/I) may MRI appearance present as NORMAL u MRI findings will be similar to OCD in these cases u “patchy edema:” also seen on T2. Treatment Nonoperative u Stiff soled shoes u Orthoses to offload the second met u May be effective for early stages (IIII) u Older patients u Non-candidates for surgery u Operative u Joint sparing u Indicated for early stage (1-3) u Remove/ drill the osteochondral defect u Dorsiflexory wedge osteotomy u Rotate good articular cartilage into the area of defect u Joint destructive u Resurface/replace joint u Joint resection/ interposition arthroplasty. u Let’s do: A Duvries metatarsal head resection u Plan out your incision overlying the affected MTPJ Dissection u Incise the skin and begin to develop the incision (stick and spread method of blunt dissection) down to the extensor tendon u You may choose to retract or lengthen the tendon u Some surgeons advocate for using a piece of tendon (EDB) to “fill the void” left by the met head. Free the plantar attachments u Free the plantar attachments using the McGlamery elevator Expose the metatarsal head u Reflect the medial and lateral collateral ligaments to free the MTPJ from soft tissue attachments Expose the metatarsal head u With the metatarsal head fully exposed, a resection will be easy u If you try to cut the bone first and then reflect the soft tissue this is more difficult. Resect the metatarsal head u Use a sagittal saw to remove the head of the metatarsal in beveled fashion. u The bevel of the cut is somewhat like a partial ray amputation Postop protocol: Duvries metatarsal head resection u Partial weight bearing in stiff soled postop shoe u Incision is dorsal so patient can generally walk on this as there is no fixation to worry about. u Counsel patient about floating toe, transfer lesions (calluses under the other metatarsal heads), swelling Lecture review u Why would Dr. Johnstone spend 15 slides reviewing functional anatomy of the lesser MTPJ? u Knowledge of the function of each structure is critical to diagnosis and hence procedure selection u Should you need to transfer a tendon, you need to pick the right one! u Recognize the clinical features (presentation) of each diagnosis u Select appropriate physical exams to formulate diagnoses u Use the physical exam to guide adjunct exams like x-rays (know which tests are appropriate) u If there is a staging system, what is the usefulness of such a system? u Can this be used to guide surgical decisions? u Be able to describe conservative care options for each pathology u Identify when surgery is warranted, and which procedure would be appropriate based on your diagnosis. Sample question 1 1. A 46 year old male patient presents to your office with tenderness and swelling at the MTPJ of the second toe, he has intense tenderness with palpation of the sulcus of the second toe and a positive digital Lachman’s test, you suspect a traumatic rupture of the plantar plate and order an MRI, which returns a result of “no tear of the plantar plate visualized” He has not responded to the past 12 weeks of taping and CAM boot treatment, you remain convinced that the plantar plate is torn, which test would give you the best evidence to support this diagnosis? a. TC-99 scan (nuclear medicine) b. Ceretek scan (nuclear medicine: WBC labelled scan) c. Computed tomography d. Arthrogram e. Musculoskeletal ultrasound Sample question 2 1. Regarding a swollen and tender third metatarsal-phalangeal joint with redness and difficulty moving the joint in a 54 year old female patient, for which of the following pathologies would a toenail fungal culture (results expected in 4 weeks) be an expected part of the workup? a. b. c. d. e. Predislocation syndrome Septic arthritis Freiberg’s infarction Capsulitis Psoriatic arthritis Bonus sample question! u Regarding Freidberg’s infarction, the following MRI and x-ray indicate that the metatarsal head has undergone a recession of the central head, and is showing medial and lateral projections, classify this according to Smile’s 1967 system? u Stage I u Stage II u Stage III u Stage IV u Stage V 1. Rationale: Sample question 1 A 46 year old male patient presents to your office with tenderness and swelling at the MTPJ of the second toe, he has intense tenderness with palpation of the sulcus of the second toe and a positive digital Lachman’s test, you suspect a traumatic rupture of the plantar plate and order an MRI, which returns a result of “no tear of the plantar plate visualized” He has not responded to the past 12 weeks of taping and CAM boot treatment, you remain convinced that the plantar plate is torn, which test would give you the best evidence to support this diagnosis? a. TC-99 scan (nuclear medicine) b. Ceretek scan (nuclear medicine: WBC labelled scan) c. Computed tomography d. Arthrogram (correct answer!) e. Musculoskeletal ultrasound Rationale: the ceretek scan and CT are not widely used in evaluation of the plantar plate due to poor visualization, as a soft tissue injury the TC-99 scan would only serve to rule out an osseous component to the patient’s pain, the ultrasound may be useful, however nothing will be quite as diagnostic as a positive arthrogram. Rationale: Sample question 2 1. Regarding a swollen and tender third metatarsal-phalangeal joint with redness and difficulty moving the joint in a 54 year old female patient, for which of the following pathologies would a toenail fungal culture (results expected in 4 weeks) be an expected part of the workup? a. Predislocation syndrome b. Septic arthritis c. Freiberg’s infarction d. Capsulitis e. Psoriatic arthritis (correct answer!) u Rationale: toenail changes are associated with psoriatic arthritis in up to 80% of patients who have PA (slide 66/67) answer choices A,C, and D are not known to be associated with infectious sources, and one should never wait 4 weeks for a case of suspected septic arthritis (this is a surgical emergency and a bacterial infection (not toenail fungus!) Bonus sample question! u Regarding Freidberg’s infarction, the following MRI and x-ray indicate that the metatarsal head has undergone a recession of the central head, and is showing medial and lateral projections, classify this according to Smile’s 1967 system? u Stage I u Stage II u Stage III (correct answer!) u Stage IV u Stage V