5 The Foot



10.1055/b-0038-160355

5 The Foot

S. Sell, S. Rehart, M. Henniger, B. Kurosch

5.1 Indications and Therapeutic Plan


In 85 to 90% of rheumatoid patients the foot is affected, to some extent also early in the disease process. The forefoot is most commonly involved, followed by the midfoot and ankle joint.


The fundamental principle of therapy—proximal before distal—also applies to the foot. Thus, lower ankle joint destruction should be addressed before treating forefoot involvement. It is, however, essential to keep in mind that every rheumatic patient requires an individual approach.


Forefoot synovectomies are rarely performed. In addition, joint-preserving procedures are becoming increasingly prevalent. The key factor in determining indications for treatment, more so than for the nonrheumatoid forefoot, is the condition of the soft tissues. On the one hand, the inflammatory process can lead to soft tissue contractures that can only be partially corrected. This plays a far greater role than the existence of bony deformities when determining indications for a joint-preservation intervention. If, for example, the great toe proximal joint is no longer reducible into a neutral position preoperatively, we believe there is tremendously increased risk of recurrence and that it is worth considering whether an arthrodesis would not be more advantageous. This is even more of a consideration if the great toe deformity has led to a fibular deviation of the second through fifth toes. The focus, therefore, should be on stabilizing and correcting the first ray.


On the other hand, the condition of the medial capsule plays a significant role in determining indications for treatment. The capsule structures are sometimes extremely elongated in rheumatoid patients and can lead to recurrence despite a good bony corrective result. It is, however, often quite difficult to evaluate the condition of the medial capsule preoperatively. Because of this, we have a frank discussion with these patients and inform them that the final decision between joint preservation or fusion will be determined intraoperatively, depending upon the soft tissues.


On the whole, the second through fifth toes are more difficult to correct than the great toes, which is an important consideration when determining the course of treatment.


Toe deformities are frequently associated with additional anatomical changes:




  • Extensor tendon contractures (consider extensor tendon elongation).



  • Dislocation of proximal joints (consider joint arthrolysis or a Weil osteotomy with dorsal wedge).



  • Lateral elongation of the capsule with fibular deviation of the toes (consider capsuloplasty and duplication).


Despite the emergence of joint-preserving operations, forefoot metatarsal head resection continues to remain the “gold standard.” It is also one of the “number one” procedures, because it is as successful and subjectively satisfying for the patient as the hip and knee prosthesis. We also favor this procedure at the outset of the surgical intervention plan outlined for the patients. The procedure can be performed from either a dorsal or a plantar approach, depending upon the surgeon’s training; both procedures presented here produce good results. It is not unusual to perform bilateral forefoot corrections in order to minimize hospitalizations.


Arthrodesis is the standard procedure for correction of the first ray in the presence of contracture. A Swanson prosthesis presents an alternative for joint destruction with correctable soft tissue.


Because the soft tissue has a pivotal role in both indications and the operative approach, it should be protected during the postoperative healing process by use of orthotics or individually fitted ergonomic equipment.


Impaired wound healing is a major issue for rheumatoid patients due to the underlying illness and its associated medication therapy.



5.2 Proximal Corrective Osteotomy


Indication


Severe rheumatic splayfoot. Rheumatic splayfoot with an intermetatarsal angle ≥ 18°. Soft tissues must be correctable. Larsen I–II destruction.


Specific disclosures for patient consent


Impaired wound healing. Pseudarthrosis. Metatarsal head necrosis with sequelae (arthrodesis). Joint stiffness. Recurrence. Infection. Tendon injury. Blood vessel, nerve injury.


Instruments


Locking plate. For L-shaped or Z-shaped screw fixation osteosynthesis, 2.7 to 4.0-mm cancellous screws.


Position


Supine. Foot in neutral position with toes pointed upward. A pelvic support and tilting of the table can be used to achieve a better ankle position. Lower the contralateral foot. The foot is positioned with the edge of the heel over the end of the table.


Intraoperative radiographic imaging is only rarely needed.


Key steps


An intermetatarsal skin incision is made between the first and second toes to repair soft tissues: release the adductor hallucis muscle and, depending upon the specific situation, perform a lateral release (see Chapter 5.3).


Surgical technique


See Fig. 5‑1, Fig. 5‑2, Fig. 5‑3, Fig. 5‑4, Fig. 5‑5.


Alternative: crescentic osteotomy at the first metatarsal base.


Postoperative aftercare


An orthotic to protect the soft tissues is worn full time for 6 weeks, and then at nighttime only for an additional 6 weeks. A forefoot decompression shoe is used for 6 weeks. After that, radiographic imaging is performed for clearance to full weight bearing. Soft cushion insoles are used after foot swelling has subsided.

Fig. 5.1 A longitudinal skin incision is made starting at the base of the first metatarsal and continued to the first metatarsophalangeal joint. The capsule is split longitudinally. Alternatively, two separate skin incisions can be made: a longitudinal 3-cm incision placed more dorsally, starting at the base of the first metatarsal, and the same incision placed more proximally on the first metatarsophalangeal joint. Since we have not found that smaller incisions reduce wound healing complications, we frequently prefer a longer incision for improved exposure. The dorsomedial neurovascular bundle is exposed. The sensory cutaneous nerve runs from dorsal to plantar, and crosses over the distal end of the more longitudinally oriented vessel.
Fig. 5.2 The first metatarsal shaft axis and the predetermined proximal osteotomy planes are marked. A closing wedge osteotomy plane has been drawn here. A similar approach is followed for an L-shaped osteotomy with screw fixation osteosynthesis. A proximal short Z-shaped osteotomy is also an alternative.
Fig. 5.3 The osteotomy is performed using two Hohmann elevators for protection. In the open-wedge technique, the lateral cortex remains intact. The osteotomy is then opened with two osteotomy chisels, taking care to preserve the integrity of the lateral cortex.
Fig. 5.4 The osteotomy edges are open. The amount of correction needed is determined from preoperative imaging and then implemented operatively. If needed, temporary K-wire fixation can be implemented to control instability or if the bone is very osteoporotic.
Fig. 5.5 Fixation is accomplished with a locking plate (plantar system as well if needed). The osteotomy gap width should remain uniform from dorsal to plantar. Plantarization of the first metatarsal base can be achieved by keeping the dorsal gap larger. A simultaneous soft tissue procedure is performed on the medial side of the proximal joint capsule apparatus.


5.3 Scarf Osteotomy


Indication


Severe rheumatic splayfoot. Rheumatoid hallux valgus with an intermetatarsal angle of 10 to 18° (20°). Soft tissues must be correctable. Larsen I–II destruction.


Specific disclosures for patient consent


Impaired wound healing. Pseudarthrosis. Metatarsal head necrosis with sequelae (arthrodesis). Recurrence. Infection. Joint stiffness. Tendon injury. Blood vessel, nerve injury.


Prosthesis placement is no longer possible following a Scarf osteotomy.


Instruments


Screw 2.3-mm or 2.7-mm with flat head. Specialized countersinkable headless screws equipped with two different threads (“Herbert” screw).


Position


Supine. Foot in neutral position with toes pointing upward. A pelvic support and tilting of the table can be used to achieve a better ankle position. Lower the contralateral foot. The foot is positioned with the edge of the heel over the end of the table.


Intraoperative radiographic imaging is only rarely needed.


Approach


See Fig. 5‑6, Fig. 5‑7.


Surgical technique


See Fig. 5‑8, Fig. 5‑9, Fig. 5‑10, Fig. 5‑11, Fig. 5‑12, Fig. 5‑13, Fig. 5‑14.


Postoperative aftercare


An orthotic to protect the soft tissues is worn full time for 6 weeks, and then at nighttime only for an additional 6 weeks. A forefoot decompression shoe is used for 6 weeks. After that, radiographic imaging is performed for clearance to full weight bearing. Soft cushion insoles are used once foot swelling has subsided.

Fig. 5.6 (a,b) A longitudinal or S-shaped skin incision is made. An S-shaped incision curved toward the second metatarsal is recommended for a simultaneous procedure on the second MTP joint. Meticulous hemostasis is necessary because pronounced venous plexuses are frequently present.
Fig. 5.7 Schematic drawing of the approach. The incision is made directly over the first metatarsal, where the risk of bleeding is lower. Blunt tissue dissection is performed down to the adductor hallucis muscle. The muscle is exposed and, if necessary, tenotomized after passing a clamp underneath. The lateral sesamoid bone is exposed (after palpation). The bone is detached and the lateral release is completed using a longitudinal incision. This must be reducible under the metatarsal head using light pressure. The release is terminated when the proximal joint is easily reducible into the desired position. If this cannot be achieved, the lateral joint capsule is weakened with multiple stab incisions. Forceful manipulation is used to achieve the desired position. 1, Adductor hallucis muscle. 2, Transverse metatarsal ligament. 3, Adductor hallucis tendon. 4, Proximal phalanx. 5, Great toe MTP joint capsule. 6, Fibular sesamoid bone. 7, Flexor hallucis brevis muscle.
Fig. 5.8 The capsule and dorsomedial neurovascular bundle are exposed. The sensory cutaneous nerve runs from dorsal to plantar, and crosses over the distal end of the more longitudinally oriented vessel. A standard longitudinal capsulotomy is performed. An L-shaped capsulotomy is used only for pronounced deformities.
Fig. 5.9 The first metatarsal head is exposed following capsulotomy, and the inflamed tissue is synovectomized. The pseudoexostosis is osteotomized in a direction tangential to the axis of the shaft. The gutter border must be preserved because there is a small risk of varus deformity.
Fig. 5.10 A horizontal osteotomy of the first metatarsal base is completed from the proximal third of the plantar side of the shaft to the distal third of the dorsal aspect. The osteotomy cut is made with the saw aimed toward the fourth metatarsal. If a plantarization is also planned to treat particularly severe second-digit metatarsalgia, the osteotomy plane is sloped slightly toward plantar.
Fig. 5.11 The final proximal and distal cuts are made at an angle of approximately 60°. This leads to a better wedge and increased stability of the osteotomy fragments. The orientation of the proximal and distal osteotomies determines the lengthening (medial closing) or shortening (medial opening) of the first metatarsal needed to achieve the preoperative surgical goals.
Fig. 5.12 The fragments are repositioned. Clinically, the first metatarsal head should come into direct contact with the second metatarsal head. This is rechecked by placing stress on the foot (forced splayfoot). As a rule, a 1-mm correction corresponds to a 1° change in the intermetatarsal angle. The metatarsal head is corrected by rotating the distal end of the fragment. We screw the fragments together with three 2.3-mm flat-head screws.
Fig. 5.13 Schematic drawing of the translation of the osteotomy surfaces. The degree of lateral translation is determined by the intermetatarsal angle (1 mm translation corresponds to approximately 1° of correction) (1). The distal metatarsal-articular angle (DMAA) is determined clinically. Rotation of the fragments (2) corrects the DMAA. This can be inspected clinically after repositioning.
Fig. 5.14 Medial capsuloplasty. The capsular tissue is frequently very elongated in rheumatoid patients. In these cases we insert a 1.1-mm interosseous anchoring hole. It is advisable to grasp the capsule distally with a special suture technique. A Mason–Allen stitch, routinely used in shoulder surgery, is quite effective. The technique involves placing a transverse stitch through the capsule. A second stitch, placed longitudinally, anchors the suture. The capsule is then closed completely.


5.4 Great Toe Metatarsophalangeal Joint Arthrodesis


Indication


Larsen III–V great toe proximal joint destruction with significant clinical symptoms. Contracted hallux deformity (varus or valgus), not passively correctable, with severe rheumatic splayfoot (Fig. 5‑15 ).


Specific disclosures for patient consent


Impaired wound healing. Pseudarthrosis. Infection. Tendon injury. Injury to blood vessels, nerves.


Instruments


Alternatives: plate, combined with a 2.7-mm lag screw; 2.7-mm cross screws. Locking plate system.


Position


Supine. Foot in neutral position with toes pointing upward. A pelvic support and tilting the table can be used to achieve a better ankle position. Lower the contralateral foot. The foot lies with the edge of the heel over the end of the table.


Intraoperative radiographic imaging is only rarely needed.


Approach


See Fig. 5‑16.


Surgical technique


See Fig. 5‑17, Fig. 5‑18, Fig. 5‑19, Fig. 5‑20, Fig. 5‑21, Fig. 5‑22, Fig. 5‑23.


Postoperative aftercare


A forefoot decompression shoe is used for 6 weeks. After that, radiographic imaging is performed for clearance to full weight bearing. Soft cushion insoles are used once foot swelling has subsided.

Fig. 5.15 Severe rheumatic splayfoot. Hallux valgus is no longer clinically correctable. Arthrodesis is indicated because of insufficient soft tissue.
Fig. 5.16 A dorsomedial longitudinal skin incision is made starting ca. 3 cm proximal to the great toe proximal joint and continued distally over it. The dorsomedial neurovascular bundle is exposed. The sensory cutaneous nerve runs from dorsal to plantar, and crosses over the distal end of the more longitudinally oriented vessel.
Fig. 5.17 The joint is exposed. Osteophytes are excised and, if necessary, a joint synovectomy is performed. The pseudoexostosis is resected tangential to the shaft axis. In contrast to a corrective osteotomy, the bony gutter is also resected here.
Fig. 5.18 Hohmann elevators are placed under the metatarsal head. A sparing osteotomy is performed on the joint surfaces. The shaft of the micro saw is used to guide the direction of the cut along the shaft axis, the blade being perpendicular to the saw. Depending upon the anatomical structure, the osteotomy is inclined approximately 3 to 4° relative to the shaft axis in order to achieve a distinct posterior extension of the toe. Follow the same procedure for the base of the proximal phalanx. If the joint still cannot be repositioned into a corrected position, additional soft tissue release must be performed. It is important to mobilize the sesamoid bone complex, since significant adhesions are usually present here. For severe secondary arthritic changes, we perform a reshaping arthroplasty.
Fig. 5.19 The resultant correction is transfixed with a K-wire. The foot is placed on a flat surface, such as a surgical pan cover of approximately the same length, and alignment of the arthrodesis is confirmed in all planes. Repositioning of the foot is performed under axial compression, in order to mimic the load during a footstep. The distance from the tip of the toe to the plate should be approximately 3 to 4 mm. The great toe should line up with the corrected remaining toes. The remaining mobility in the great toe distal joint is tested to ensure that it makes contact with the plate during plantar flexion and has at least 1 cm clearance from the plate during dorsiflexion.
Fig. 5.20 The arthrodesis is adjusted and compressed. A 2.7-mm interfragmentary compression screw (arrow) is inserted from distal to proximal. This screw should be located in the plantar half of the shaft.
Fig. 5.21 A five-hole neutralization plate is attached. If the bones are severely osteoporotic, a locking plate can be attached on the dorsal side. An alternative technique is to place a second interfragmentary compression screw from proximal (arrow). We perform both techniques in combination if the bones are very osteoporotic.
Fig. 5.22 Two screws are inserted on both the proximal and distal ends of the plate. Care must be taken with the second proximal screw, as it usually sits at the level of the sesamoid bone complex. For severely osteoporotic bone, the screw length must be measured carefully. If in doubt, it should be visually checked plantarly to avoid placement of an excessively long screw.
Fig. 5.23 A secure capsule closure is necessary for wound healing and to adequately cover the metal surfaces.

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May 21, 2020 | Posted by in RHEUMATOLOGY | Comments Off on 5 The Foot
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