Hallux Rigidus and Sesamoid Pathology





KEY FACTS


Hallux Rigidus





  • Hallux rigidus is the most common arthritic condition in the foot.



  • Hallux rigidus tends to be bilateral, although it is often not synchronous.



  • The 1st metatarsophalangeal (MTP) joint generally becomes stiffer and more painful as the arthritis progresses, although progression is inconsistent. Some patients will progress linearly, while others’ symptoms will remain consistent over time.



  • Nonoperative treatment is similar to nonoperative treatment for arthritis in any joint with the added component of a stiff insert or shoe to limit 1st MTP motion.



  • Operative treatment depends on how advanced the arthritis is, although symptoms are the best indicator of what treatment is most appropriate. Joint-sparing procedures (cheilectomy, Moberg osteotomy) are generally used for less severe arthritis, and fusion has traditionally been the gold standard for more severe arthritis. Implant arthroplasty with a synthetic implant is not inferior to fusion in early data.



Sesamoid Pathology





  • Sesamoiditis is a poorly understood pathology that can cause significant pain and disability. Treatment consists of offloading or sesamoidectomy for refractory cases.



  • Turf toe injuries can be devastating injuries to the big toe and typically require surgical reconstruction and repair of the plantar tissues of the 1st MTP joint.







A 50-year-old female patient with hallux rigidus symptoms as her primary complaint is shown. She also had some hallux valgus. She had tried shoe modifications without much decrease in her symptoms.








The dorsal osteophyte is seen at the 1st metatarsophalangeal joint in the same patient. The osteophyte was rubbing on her shoe, which made shoewear difficult.








A cheilectomy was performed with a median eminence resection and a combination of a Moberg and Akin osteotomy taking out a dorsomedial wedge to allow for some effective increase in dorsiflexion, while also correcting the bunion to some degree.








The lateral view shows the degree to which the dorsal osteophyte was resected, while also showing the fixation for the phalangeal osteotomy. The patient reported an improvement both in pain and function after surgery.






TERMINOLOGY





  • Osteoarthritis of the 1st metatarsophalangeal (MTP) joint is termed hallux rigidus. Hallux refers to the 1st ray, while the term rigidus is applied since the 1st MTP generally becomes stiff as the disease progresses.






  • The inciting cause is not entirely clear in this pathology, although the arthritis typically affects the dorsal aspect of the joint first.





EPIDEMIOLOGY





  • In 1 epidemiologic study of hallux rigidus, 70% of patients had bilateral disease.




    • Indeed, hallux rigidus is often bilateral, although not always synchronous.







  • 66% of affected individuals were female.




    • An older study had noted hallux rigidus to be much more common in men, although another more recent study had 63% female patients.







  • The mean age at onset was 44 years (range: 14-68 years), and the duration of symptoms prior to treatment was 6 years.






  • 22% of patients recalled some trauma to the hallux; 74% of these patients had unilateral disease.





Etiology





  • This is not entirely clear and may represent a group of pathologies that have a similar endpoint.



Theorized Predisposing Factors





  • Hindfoot valgus has been theorized to cause increased strain on the MTP joint and was associated with a 23% increased risk of hallux rigidus in 1 study.



  • The relative length of the 1st metatarsal has also been theorized as a potentially causative factor in hallux rigidus.




    • A few radiographic studies have noted relatively longer 1st rays in those patients with hallux rigidus, although others have noted no correlation.



    • Metatarsus primus elevatus, or an elevation of the 1st metatarsal in the sagittal plane, has been theorized as a cause of hallux rigidus. The theory goes that dorsiflexion at the great toe is limited due to tightening of the plantar fascia caused by elevation of the great toe, which leads to dorsal impingement at the joint and subsequent arthritis.




      • Numerous studies have largely debunked this theory, as metatarsal elevation has been found in patients both ± hallux rigidus. Further, in those patients with elevation and hallux rigidus, the degree of arthrosis did not linearly correlate with the degree of elevation. It is ultimately unclear whether the elevation is a cause or an effect of hallux rigidus.





  • Trauma to the 1st MTP joint can certainly be a cause of subsequent arthritis, although articular injuries of the 1st MTP joint are generally uncommon.



  • Osteochondral lesions of the metatarsal head are increasingly recognized as a potential cause of pain in the 1st MTP joint as well as possibly being a precursor to hallux rigidus.



  • Inflammatory arthropathies can certainly affect the 1st MTP joint, although this pathology typically involves more than just the 1st MTP. Also, with the advent of disease-modifying antirheumatic drugs, the incidence of severe forefoot pathology in these patients appears to be decreasing.





History and Physical Exam Findings


History





  • Patients will typically complain of pain in the big toe, especially with push off. Essentially, any movement that requires dorsiflexion of the big toe will be painful.



  • The time course of symptoms can be variable. Not uncommonly, patients can have mild symptoms for years and then have sudden exacerbations of unclear origin.



  • People’s ability to adapt to pain can be manifested in this condition in the following way. Since push off or toe off requires dorsiflexion and is painful, patients will often “roll out,” i.e., disengage the big toe when they push off or “roll” their foot to the outside so that the push off comes through the lesser toe joints and involves the big toe less. Rarely, patients will present with lateral (e.g., 4th) metatarsal stress fractures that are otherwise uncommon due to this mechanical adaptation.



  • Interestingly, unilateral hallux rigidus has been found to produce calf asymmetry due to a lack of fully engaging the calf musculature at push off. The atrophy develops over a long period of time and, thus, may not be noticed until it is quite pronounced. In this setting, this calf asymmetry has occasionally been thought to represent abnormal swelling on what is ostensibly the normal side, leading to an expensive, and at times invasive, work-up.



Physical Examination





  • Patients will often have a dorsal osteophyte that is variably prominent emanating from the 1st metatarsal head. Generally speaking, patients can have pain from this osteophyte alone, in which case, the pain will be with dorsal palpation; they can have pain from the arthritis, in which case, pain will occur with motion of the 1st MTP; or the patients can have some degree of both.



  • Range of motion of the 1st MTP joint will often be restricted to some degree, although it must be noted that “normal” motion at the 1st MTP joint can be incredibly variable and is very much a moving target. As an example, normal total 1st MTP motion for a large, burly man may be only ~ 50-60°, while a lithe female dancer may have close to 180° of motion. In this setting, the contralateral side can be used as an internal control, although only in those situations in which it is unaffected.



  • Early in the course of the disease, pain typically occurs dorsally and with dorsiflexion as above. As the arthritis progresses in later stages, pain can occur throughout the joint and with any motion of the joint



  • Patients can have some evidence of lesser metatarsalgia due to lack of engagement of the big toe as above.





Imaging


Radiographs





  • Weight-bearing AP, oblique, and lateral radiographs are warranted.




    • General radiographic signs of arthritis, such as joint space narrowing, subchondral sclerosis, subchondral cysts, and osteophyte formation, prevail.



    • While the progression of the symptoms of the disease generally parallels the severity of the radiographic findings, this statement is not universally true, as there are plenty of patients whose radiographic disease is worse than their clinical disease.




Advanced Imaging





  • Advanced imaging is seldom necessary in the setting of hallux rigidus. However, in those patients that may have an osteochondral lesion of the metatarsal head without clear arthritis, an MR can be beneficial to identify and characterize such a lesion.





Classification





  • Coughlin and Shurnas developed the most widely used grading system for severity of hallux rigidus, utilizing both clinical and radiographic parameters.




    • Grade 0




      • 10-20% loss of motion of contralateral side, 40-60° motion, normal radiographs, no pain




    • Grade 1




      • Loss of 20-50% of motion of normal side, 30-40° motion



      • Radiographs show dorsal osteophyte mainly with minimal other findings; mild, occasional pain; pain at extremes of motion (i.e., maximal dorsiflexion or plantarflexion).




    • Grade 2




      • Loss of 50-75% of motion of normal side, 10-30° motion



      • Radiographs show dorsal, lateral, medial osteophytes, which may make metatarsal head appear flattened; up to 25% of dorsal joint space involved; mild to moderate joint space narrowing; sesamoids not involved.



      • Moderate to severe pain and stiffness, maximal pain just before maximal dorsiflexion or plantarflexion on exam




    • Grade 3




      • Almost complete loss of motion with < 10° arc



      • Radiographs are similar to grade 2 with notable exceptions that entire joint is involved, and sesamoids may be involved.



      • Nearly constant pain and stiffness, pain still at extremes but not in mid range of motion




    • Grade 4




      • Motion and radiographic findings similar to grade 3; primary difference is that pain is throughout range of motion.







Treatment


Nonoperative Treatment





  • If the pain is somewhat acute in onset, a brief period of time in a CAM Walker boot with oral antiinflammatories may be appropriate in an effort to quell inflammation and decrease pain.



  • The basic concept behind nonoperative treatment essentially follows the same logic, i.e., minimize motion and inflammation at the 1st MTP joint. A deep toe box shoe can be beneficial as well in an effort to decrease pain from rubbing on dorsal osteophytes.



  • Motion at the 1st MTP joint can be restricted using any of a number of different types of shoe inserts. In general, stiff inserts of some description are used to restrict primarily 1st MTP dorsiflexion. What individual type of insert is used depends on surgeon preference and cost.




    • Options include full-length carbon fiber foot plates or an orthotic with a Morton extension. On occasion, simply a stiff-soled shoe, such as a clog, may be sufficient.




  • As with arthritis in any joint, antiinflammatories may be of some benefit and are certainly worth trying.



  • Steroid injections can be used judiciously, although some surgeons worry about potential effects to the soft tissue envelope in patients who may ultimately need surgery, given the subcutaneous nature of the joint.



  • There are few studies specifically of nonoperative treatment, although 1 study of 24 feet noted that surgery could be avoided with little progression of disease over a 12-year period.



Operative Treatment





  • Operative treatment is generally broken down into 2 basic types of options. Either an effort is made to retain the joint in those patients with milder disease, or the joint is eliminated in more severe disease.




    • For milder disease (grades 1 and 2), joint preservation is preferred.




      • A cheilectomy, or dorsal exostectomy, is the procedure of choice. In this procedure, the joint is approached dorsally, and 20-30% of the dorsal metatarsal head is excised with the dorsal osteophyte. The goal at the time of surgery is to get at least 60° of dorsiflexion. Cheilectomy had shown good results both in the short term and in the long term, although surgeons must counsel patients that it is not a curative operation, and the arthritis and symptoms may return at some point in the future.



      • Phalangeal osteotomies have been added to try to allow for better effective dorsiflexion by “stealing” some plantarflexion motion. The Moberg osteotomy, a dorsal closing wedge osteotomy, makes it so that the toe engages the ground later in push off, which effectively increases dorsiflexion of the big toe. This osteotomy generally works well for hallux rigidus, and some authors have pushed to use it with cheilectomy even in advanced cases of hallux rigidus, i.e., grade 3.



      • While a host of metatarsal osteotomies have been described for hallux rigidus, outcomes have been inconsistent and inconsistently reported. Moreover, many of the osteotomies seek to address issues that are not clearly pathologic, such as metatarsal elevation or relative length. As a result, these osteotomies are not routinely recommended.





  • For more severe disease (grades 3 and 4), more ablative procedures are generally recommended.




    • The Keller procedure, a resection arthroplasty of the 1st MTP joint, has been used historically for hallux rigidus. In this procedure, the base of the proximal phalanx is resected. Although this procedure can work reasonably well for pain relief, it diminishes push-off power and thereby negatively impacts patient function. It is therefore rarely used.



    • Another option is the capsular interposition arthroplasty. This option has historically been reserved for those patients with severe hallux rigidus who do not want a fusion, often women who have a desire to wear heels. In this procedure, a cheilectomy is performed as well as a Keller. However, crucially, the proximal phalangeal base is retained and with it the capsular and flexor hallucis brevis insertions, thereby allowing retention of push-off power.




      • Results from this procedure were generally good with ~ a 10% rate of subsequent conversion to arthrodesis.




    • Metatarsophalangeal arthrodesis has been and remains the gold standard or treatment for end-stage hallux rigidus. It has long been a reliable option for providing pain relief in this group of patients.




      • There are a variety of techniques of fixation without any clear hierarchy as to which is best. Most surgeons either use a lag screw and plate construct or crossed screws.



      • Patients are generally kept non-weight bearing for 4 weeks after surgery.



      • Results are uniformly good; patients often have a somewhat unfounded dislike of fusion operations, as they feel they will be unable to walk appropriately. However, clinical studies and gait studies show uniform improvement in many parameters after 1st MTP fusion, and patients are often able to be active at a level that was not possible prior to fusion.



      • Total joint arthroplasty can work for hallux rigidus, but, when it fails, it tends to fail catastrophically, with significant bone loss, leaving a difficult reconstructive situation. Many surgeons view total joint arthroplasty as an inappropriate treatment for hallux rigidus at this point.




    • More recently, a synthetic cartilage implant has been developed for those patients with end-stage disease who would like to avoid fusion.




      • The implant works by distracting the joint to some degree, thereby hopefully increasing motion to some degree and decreasing pain.



      • An initial noninferiority study showed that it was not overtly inferior to arthrodesis. Moreover, if it does fail, surgical revision to arthrodesis is easily accomplished.




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Oct 29, 2019 | Posted by in ORTHOPEDIC | Comments Off on Hallux Rigidus and Sesamoid Pathology
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