Orthopedics Today Grand Rounds

53-year-old woman with continued pain after first metatarsophalangeal arthroplasty

A 53-year-old woman with rheumatoid arthritis on oral prednisone presented to a podiatric surgeon after a lifelong history of hallux valgus and lesser toe deformities. After failure of conservative management options, she opted for surgical management with first metatarsophalangeal joint arthroplasty with a double-stem silastic implant. Hammertoe deformities of her second through fifth digits were treated with lesser metatarsal head resections with transarticular pin fixation. The patient’s postoperative period was unremarkable, but after about 2 months, she noticed recurrence of the deformity of the lesser toes. She also developed a painful plantar prominence at the hallux metatarsophalangeal with return of the valgus deformity. After 4 years of persistent pain, she was referred to orthopedic surgery for further evaluation.

Joshua D. Johnson
Nicholas A. Trasolini

On physical examination, the patient’s right foot demonstrated hallux valgus deformity with hammertoe deformity of the lesser toes (Figure 1). There was also a visible and palpable mass on the plantar aspect of the first metatarsophalangeal (MTP) joint. Her fifth metatarsal fat pad was everted laterally and she was unable to move any of her lesser MTP joints. The patient’s extensor hallucis longus and flexor hallucis longus function was 4 of 5.

Figure 1. Preoperative clinical appearance of the affected foot is shown.

Source: Eric W. Tan, MD

What is your diagnosis?

See answer on next page.

Failed first MTP arthroplasty with extensive osteolysis, recurrent hammertoe deformity of the lesser digits

Radiographic evaluation demonstrated a failed silastic prosthesis lodged in the plantar first MTP fat pad with severe hallux valgus, along with significant osteolysis of the first metatarsal and proximal phalanx (Figure 2). In addition, there was persistent malalignment of the patient’s lesser MTP joints with evidence of previous resection arthroplasty of the joints.

Given the significance of the deformity, persistent pain and shoe wear difficulties, revision surgery was planned. The patient underwent removal of the failed hallux implant with intercalary fusion of the first MTP joint, using a structural bone allograft. In addition, she underwent revision lesser metatarsal head resections with percutaneous pin fixation. Ipsilateral iliac crest bone marrow aspirate concentrate was harvested for biologic supplementation of her allograft reconstruction.

The first MTP procedure was performed through a dorsal approach to the first MTP joint. The dorsal capsule was incised and reflected. The joint was gently distracted revealing the failed silastic implant (Figure 3). The implant was removed and the ligaments surrounding the MTP joints were released to allow further access to the joint. In addition, the extensor hallucis longus was Z-lengthened to allow for further lengthening of the medial column.

As visualized on the preoperative radiographs, there was significant osteolysis with cavitation of the metatarsal head and base of the proximal phalanx secondary to wear of the silastic implant. Care was taken to remove all implant debris in addition to the fibrous tissue that developed within the distal aspect of the first metatarsal and base of the proximal phalanx. The bone surfaces were gently debrided to stable borders. The resulting defect measured 25 mm (Figure 4).

Figure 2. Shown are anteroposterior (AP) (a) and lateral (b) radiographs.
Figure 3. Intraoperative photographs show the dorsal capsule after incision and reflection. The failed silastic implant was clearly visible (a). The procedure allowed for subsequent removal of the implant (b).

To span the gap, we selected an allograft Cannulated Bone Dowel (Arthrex) typically used for revision ACL surgery. It is a dense cancellous dowel that is available in various sizes; the dowel used in this case measured 18 mm by 35 mm. The diameter was selected to best match the width of the patient’s bone. To maximize the contact surface area between the allograft and the bony surfaces of the metatarsal and proximal phalanx, cup and cone reamers were used. The dense cancellous nature of the dowel allowed it to be easily shortened and molded by the reamer while the structural integrity to support compression and fixation was maintained.

We used the cup reamer on both the metatarsal and proximal phalanx to prevent any additional shortening of the bones. Conversely, both surfaces of the dowel were prepared with the corresponding cone reamer to allow for the congruence needed to maximize the surface area for bony apposition. The dowel was soaked in the concentrated bone marrow aspirate and placed within the defect. Provisional reduction between the allograft dowel and the metatarsal and proximal phalanx was held with K-wires (Figure 5). Final fixation was achieved with nitinol compression staples supplemented by a dorsal arthrodesis plate.

The lesser toe deformities were addressed by balancing soft tissues through extensor digitorum longus and brevis release, revision resection arthroplasty, and realignment and stabilization with K-wire fixation. At the end of the case, a normal cascade of the metatarsals was achieved across all digits (Figure 6).

Postoperatively, the patient was initially placed in a well-padded short-leg splint and made non-weight-bearing on the left lower extremity. The pins across the lesser toes were removed at 6 weeks postoperatively. Progressive weight-bearing in a short cam boot, as well as physical therapy, began at 8 weeks postoperatively. The patient transitioned to normal supportive shoes at 12 weeks postoperatively. By 16 weeks postoperatively, she returned to work without restrictions and reported no forefoot pain. Her fixation and alignment are well maintained radiographically (Figure 7).

Figure 4. An intraoperative fluoroscopic image shows the extent of the bony defect after removal of the failed silastic implant and preparation of the bone with a cup reamer. The length of the line shown is 25 mm.
Figure 5. The cancellous bone dowel used was shortened and shaped using a cone reamer that corresponded to the cone reamer used to prepare the host bone surfaces (a). The dowel was soaked in concentrated bone marrow aspirate and provisionally held in place with K-wire fixation prior to definitive fixation (b).
Figure 6. Immediate postoperative AP (a), oblique (b) and lateral (c) radiographs show restoration of the normal cascade of digits, as well as restoration of the length of the first ray.
Figure 7. At 4-months postoperatively, AP (a), oblique (b) and lateral (c) radiographs show a well fixed graft and normal digit alignment that is well maintained without interval failure.

Discussion

One of the most common pathological conditions that foot and ankle specialists encounter is hallux valgus. Nearly all patients are initially treated conservatively with shoe modifications, toe spacers, insoles, orthoses and physical therapy. If nonoperative treatment fails, surgery is indicated. Surgical options depend on several factors, such as the severity of the deformity and/or presence of arthrosis. In mild to moderate cases, realignment osteotomies in hallux valgus can be effective to eliminate pain. If deformity is more severe with significant arthrosis present, patients typically require fusion of the first MTP joint. Arthrodesis has been considered the gold standard for degenerative conditions of the first MTP, such as osteoarthritis, rheumatoid arthritis and severe hallux valgus.

More recently, alternative joint-sparing procedures have gained some popularity, with options including interposition arthroplasty, Cartiva (Wright Medical Technology), silastic implants and metal implants. These are indicated only in cases of hallux rigidus without hallux valgus due to risk of recurrent deformity. Should these modalities fail, however, arthrodesis is the salvage procedure of choice. Revision of these failed joint-sparing hallux procedures presents a challenge to surgeons due to osteolysis with significant bone loss that can occur. Removal of the implant with primary end-to-end fusion may result in excessive shortening of the metatarsal with subsequent transfer overload of the lesser metatarsals. These changes to the alignment and balance of the foot result in continued pain and dysfunction.

Interpositional bone graft has been proposed as a viable method of addressing the issue of bone loss and previous papers have noted the use of autogenous and allogenic bone grafts, as well as the use cortical and cancellous harvested bone. However, these grafting options can be technically challenging and have failure rates 25% to 58%. In 2000, James W. Brodsky, MD, and colleagues reported good outcomes in 12 patients undergoing salvage first MTP fusion using tricortical iliac crest bone graft, with eleven of the cases going on to have radiographic arthrodesis. This series, it should be noted, did not include patients with rheumatoid arthritis or diabetes mellitus. In this case, the patient did not want a separate hip incision and was concerned about the possibility of donor site pain, so iliac crest bone graft was not an option. In addition, Federico G. Usuelli, MD, and colleagues reported a 25% nonunion rate in 12 patients undergoing salvage arthrodesis with an autologous cancellous bone block harvested from the calcaneus. Similarly, Mark S. Myerson, MD, and colleagues reported a nonunion rate of 21% among 24 patients who underwent salvage arthrodesis using either autograft or structural allograft. Despite these relatively high nonunion rates, there is a lack of alternative options and good outcomes can be achieved in a majority of patients.

Some pre-shaped commercial products can address MTP bone loss in revision arthrodesis cases. However, they are expensive and are limited in terms of sizing because they are available in only two diameters, but several lengths. Furthermore, the commercially available graft is pre-shaped such that there is a convex and concave end with no variation in shape. The technique described in this article used a novel approach with cancellous bone dowels classically designed for revision ACL ligament reconstruction. It allows for salvage of medial column length with a more customizable, low-cost, widely available off-the shelf product. After an appropriate diameter dowel is chosen, either through preoperative templating or intraoperative observation, the dowel can be easily cut to the desired length. Further, because the ends are shaped using paired cup-and-cone reamers, the surgeon can readily select any combination of convex and concave ends to best address the morphology of the bone loss and maximize bony contact without having to excessively resect additional native bone to accommodate the graft.

Salvage arthrodesis after failed first MTP arthroplasty is a difficult procedure due to osteolysis and first-ray bone loss. We present a novel technique to manage severe bone loss using a more widely available, customizable allograft. We believe this technique will be of particular benefit to surgeons worldwide that may not have access to specialty MTP grafts, surgeons who must accommodate institutional financial constraints or to patients who may have an unusual anatomy that is not amenable to pre-shaped solutions.

Disclosures: Tan reports he is a paid consultant for Arthrex and Orbis Medical Devices. Harley and Kang report no relevant financial disclosures.

A 53-year-old woman with rheumatoid arthritis on oral prednisone presented to a podiatric surgeon after a lifelong history of hallux valgus and lesser toe deformities. After failure of conservative management options, she opted for surgical management with first metatarsophalangeal joint arthroplasty with a double-stem silastic implant. Hammertoe deformities of her second through fifth digits were treated with lesser metatarsal head resections with transarticular pin fixation. The patient’s postoperative period was unremarkable, but after about 2 months, she noticed recurrence of the deformity of the lesser toes. She also developed a painful plantar prominence at the hallux metatarsophalangeal with return of the valgus deformity. After 4 years of persistent pain, she was referred to orthopedic surgery for further evaluation.

Joshua D. Johnson
Nicholas A. Trasolini

On physical examination, the patient’s right foot demonstrated hallux valgus deformity with hammertoe deformity of the lesser toes (Figure 1). There was also a visible and palpable mass on the plantar aspect of the first metatarsophalangeal (MTP) joint. Her fifth metatarsal fat pad was everted laterally and she was unable to move any of her lesser MTP joints. The patient’s extensor hallucis longus and flexor hallucis longus function was 4 of 5.

Figure 1. Preoperative clinical appearance of the affected foot is shown.

Source: Eric W. Tan, MD

What is your diagnosis?

See answer on next page.

PAGE BREAK

Failed first MTP arthroplasty with extensive osteolysis, recurrent hammertoe deformity of the lesser digits

Radiographic evaluation demonstrated a failed silastic prosthesis lodged in the plantar first MTP fat pad with severe hallux valgus, along with significant osteolysis of the first metatarsal and proximal phalanx (Figure 2). In addition, there was persistent malalignment of the patient’s lesser MTP joints with evidence of previous resection arthroplasty of the joints.

Given the significance of the deformity, persistent pain and shoe wear difficulties, revision surgery was planned. The patient underwent removal of the failed hallux implant with intercalary fusion of the first MTP joint, using a structural bone allograft. In addition, she underwent revision lesser metatarsal head resections with percutaneous pin fixation. Ipsilateral iliac crest bone marrow aspirate concentrate was harvested for biologic supplementation of her allograft reconstruction.

The first MTP procedure was performed through a dorsal approach to the first MTP joint. The dorsal capsule was incised and reflected. The joint was gently distracted revealing the failed silastic implant (Figure 3). The implant was removed and the ligaments surrounding the MTP joints were released to allow further access to the joint. In addition, the extensor hallucis longus was Z-lengthened to allow for further lengthening of the medial column.

As visualized on the preoperative radiographs, there was significant osteolysis with cavitation of the metatarsal head and base of the proximal phalanx secondary to wear of the silastic implant. Care was taken to remove all implant debris in addition to the fibrous tissue that developed within the distal aspect of the first metatarsal and base of the proximal phalanx. The bone surfaces were gently debrided to stable borders. The resulting defect measured 25 mm (Figure 4).

Figure 2. Shown are anteroposterior (AP) (a) and lateral (b) radiographs.
Figure 3. Intraoperative photographs show the dorsal capsule after incision and reflection. The failed silastic implant was clearly visible (a). The procedure allowed for subsequent removal of the implant (b).

To span the gap, we selected an allograft Cannulated Bone Dowel (Arthrex) typically used for revision ACL surgery. It is a dense cancellous dowel that is available in various sizes; the dowel used in this case measured 18 mm by 35 mm. The diameter was selected to best match the width of the patient’s bone. To maximize the contact surface area between the allograft and the bony surfaces of the metatarsal and proximal phalanx, cup and cone reamers were used. The dense cancellous nature of the dowel allowed it to be easily shortened and molded by the reamer while the structural integrity to support compression and fixation was maintained.

We used the cup reamer on both the metatarsal and proximal phalanx to prevent any additional shortening of the bones. Conversely, both surfaces of the dowel were prepared with the corresponding cone reamer to allow for the congruence needed to maximize the surface area for bony apposition. The dowel was soaked in the concentrated bone marrow aspirate and placed within the defect. Provisional reduction between the allograft dowel and the metatarsal and proximal phalanx was held with K-wires (Figure 5). Final fixation was achieved with nitinol compression staples supplemented by a dorsal arthrodesis plate.

The lesser toe deformities were addressed by balancing soft tissues through extensor digitorum longus and brevis release, revision resection arthroplasty, and realignment and stabilization with K-wire fixation. At the end of the case, a normal cascade of the metatarsals was achieved across all digits (Figure 6).

Postoperatively, the patient was initially placed in a well-padded short-leg splint and made non-weight-bearing on the left lower extremity. The pins across the lesser toes were removed at 6 weeks postoperatively. Progressive weight-bearing in a short cam boot, as well as physical therapy, began at 8 weeks postoperatively. The patient transitioned to normal supportive shoes at 12 weeks postoperatively. By 16 weeks postoperatively, she returned to work without restrictions and reported no forefoot pain. Her fixation and alignment are well maintained radiographically (Figure 7).

Figure 4. An intraoperative fluoroscopic image shows the extent of the bony defect after removal of the failed silastic implant and preparation of the bone with a cup reamer. The length of the line shown is 25 mm.
Figure 5. The cancellous bone dowel used was shortened and shaped using a cone reamer that corresponded to the cone reamer used to prepare the host bone surfaces (a). The dowel was soaked in concentrated bone marrow aspirate and provisionally held in place with K-wire fixation prior to definitive fixation (b).
Figure 6. Immediate postoperative AP (a), oblique (b) and lateral (c) radiographs show restoration of the normal cascade of digits, as well as restoration of the length of the first ray.
Figure 7. At 4-months postoperatively, AP (a), oblique (b) and lateral (c) radiographs show a well fixed graft and normal digit alignment that is well maintained without interval failure.
PAGE BREAK

Discussion

One of the most common pathological conditions that foot and ankle specialists encounter is hallux valgus. Nearly all patients are initially treated conservatively with shoe modifications, toe spacers, insoles, orthoses and physical therapy. If nonoperative treatment fails, surgery is indicated. Surgical options depend on several factors, such as the severity of the deformity and/or presence of arthrosis. In mild to moderate cases, realignment osteotomies in hallux valgus can be effective to eliminate pain. If deformity is more severe with significant arthrosis present, patients typically require fusion of the first MTP joint. Arthrodesis has been considered the gold standard for degenerative conditions of the first MTP, such as osteoarthritis, rheumatoid arthritis and severe hallux valgus.

More recently, alternative joint-sparing procedures have gained some popularity, with options including interposition arthroplasty, Cartiva (Wright Medical Technology), silastic implants and metal implants. These are indicated only in cases of hallux rigidus without hallux valgus due to risk of recurrent deformity. Should these modalities fail, however, arthrodesis is the salvage procedure of choice. Revision of these failed joint-sparing hallux procedures presents a challenge to surgeons due to osteolysis with significant bone loss that can occur. Removal of the implant with primary end-to-end fusion may result in excessive shortening of the metatarsal with subsequent transfer overload of the lesser metatarsals. These changes to the alignment and balance of the foot result in continued pain and dysfunction.

Interpositional bone graft has been proposed as a viable method of addressing the issue of bone loss and previous papers have noted the use of autogenous and allogenic bone grafts, as well as the use cortical and cancellous harvested bone. However, these grafting options can be technically challenging and have failure rates 25% to 58%. In 2000, James W. Brodsky, MD, and colleagues reported good outcomes in 12 patients undergoing salvage first MTP fusion using tricortical iliac crest bone graft, with eleven of the cases going on to have radiographic arthrodesis. This series, it should be noted, did not include patients with rheumatoid arthritis or diabetes mellitus. In this case, the patient did not want a separate hip incision and was concerned about the possibility of donor site pain, so iliac crest bone graft was not an option. In addition, Federico G. Usuelli, MD, and colleagues reported a 25% nonunion rate in 12 patients undergoing salvage arthrodesis with an autologous cancellous bone block harvested from the calcaneus. Similarly, Mark S. Myerson, MD, and colleagues reported a nonunion rate of 21% among 24 patients who underwent salvage arthrodesis using either autograft or structural allograft. Despite these relatively high nonunion rates, there is a lack of alternative options and good outcomes can be achieved in a majority of patients.

Some pre-shaped commercial products can address MTP bone loss in revision arthrodesis cases. However, they are expensive and are limited in terms of sizing because they are available in only two diameters, but several lengths. Furthermore, the commercially available graft is pre-shaped such that there is a convex and concave end with no variation in shape. The technique described in this article used a novel approach with cancellous bone dowels classically designed for revision ACL ligament reconstruction. It allows for salvage of medial column length with a more customizable, low-cost, widely available off-the shelf product. After an appropriate diameter dowel is chosen, either through preoperative templating or intraoperative observation, the dowel can be easily cut to the desired length. Further, because the ends are shaped using paired cup-and-cone reamers, the surgeon can readily select any combination of convex and concave ends to best address the morphology of the bone loss and maximize bony contact without having to excessively resect additional native bone to accommodate the graft.

Salvage arthrodesis after failed first MTP arthroplasty is a difficult procedure due to osteolysis and first-ray bone loss. We present a novel technique to manage severe bone loss using a more widely available, customizable allograft. We believe this technique will be of particular benefit to surgeons worldwide that may not have access to specialty MTP grafts, surgeons who must accommodate institutional financial constraints or to patients who may have an unusual anatomy that is not amenable to pre-shaped solutions.

PAGE BREAK

Disclosures: Tan reports he is a paid consultant for Arthrex and Orbis Medical Devices. Harley and Kang report no relevant financial disclosures.

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