Clinical presentation is most often painful hallux valgus or painful hallux rigidus which is having a negative impact on the patient’s lifestyle. They may state that their activities of daily living are becoming increasing more difficult as the duration of the disease progresses. Coughlin and Shurnas [43] found that the average age of onset of symptoms is approximately 43 years old with a surgery occurring most commonly around 50 years .

Visual examination often reveals a first MTP joint that appears enlarged secondary to prominent periarticular osteophytes or a pronounced metatarsal head. Rubor is also seen in association with irritation from shoe gear or from degenerative synovitis. Osteophyte formation and joint maladaptation can become irritating to the dorsomedial cutaneous nerve as it courses over the joint causing shooting pain into the toe. The patient may elicit a positive Tinel’s with percussion of the nerve. These symptoms can also become worse with tighter fitting shoe gear and activities that increase motion at the MTP joint. Pain may be described as deep aching to sharp and radiating depending on nerve involvement and extent of cartilage damage. Patients may sometimes present with the primary complaint of lesser metatarsalgia in the setting of hallux rigidus as the patient does not perceive that they are shifting their body weight laterally to prevent motion passing through the MTP joint [44]. A diffuse callus under the lesser metatarsals and hammertoe deformities may be evidence of this shifting to the lateral foot.

Limited motion in the sagittal is a common objective finding. In patients with existing hallux valgus deformities, the hallux is often found to be track bound and may not easily reduce into a rectus position. Crepitus is often present in later stages of DJD and may be a sign of significant joint damage, especially if there is pain with midrange of motion [43, 45]. This is best assessed by firmly holding the base of the proximal phalanx and applying axial pressure into the joint while placing the hallux through dorsiflexion and plantar flexion. A catching, grinding, or popping sensation may be felt, suggesting the extent of damage to the joint surfaces.

Anteroposterior (AP), oblique, and lateral weight-bearing radiographs can be helpful in correctly staging the level of osteoarthritis and aid in choosing the correct procedure. In the AP radiograph, the metatarsal head is often found to be flattened and widened with excessive osteophyte formation, joint space narrowing, joint mice, and subchondral eburnation. Cysts may also be readily apparent as lytic areas in the metatarsal head and hypertrophy of the sesamoids may be likely findings in late stages. The lateral radiograph best demonstrates the formation of a dorsal osteophyte off the head of the metatarsal and can further aid in determining the stage of disease (Fig. 16.1). Care should be taken to look at both the AP and lateral radiographs to ensure proper staging of the severity of osteoarthritis. A large dorsal osteophyte may give a false impression on severity as it can obstruct or even falsely distract the joint space [28, 46].

Multiple classifications have been proposed for first MTP joint arthritis [47, 48]. The majority of these have been based on radiographic evaluation such as the three-stage classification proposed by Hattrup and colleagues in the 1980s [49]. Coughlin and Shurnas [43] later developed a more comprehensive classification that is based on the remaining range of motion and radiograph and clinical findings. This classification takes these findings to grade the severity of the disease (Table 16.2). As we have noted above, surgeons should look beyond the radiographic grade of severity and focus on important patient factors such as age, activity level, and patient expectations when selecting the most appropriate surgical technique .

The incisional approach is similar whether performing a resection or implant arthroplasty . A linear or curvilinear incision is made dorsally just medial to the extensor tendon over the distal first metatarsal and first MTPJ and extending halfway down the proximal phalanx. This approach works well as this allows good access to the medial, lateral, and plantar structures. Care should be taken to identify and retract the medial dorsal cutaneous nerve as well as the extensor hallucis longus.

The medial eminence along with any dorsal and lateral osteophytes is resected from the first metatarsal head with a sagittal saw as this allows the capsule to advance more easily across the joint space. A lateral release may be needed in cases of severe hallux valgus, but care is taken to preserve some of this tissue as it is needed for later transposition of the “U” capsulotomy . Release of the plantar first MTP joint is only performed in the most severe and rigid cases, and care must be taken to preserve the flexor tendon as this is also needed later in the repair. Removal of the fibular sesamoid may be considered in severe cases of hallux valgus [51], but this is rarely if ever needed with an appropriate lateral release.

Up to 30–40% of the base of the proximal phalanx can be resected with a traditional Keller. However, the modified resection arthroplasty removes an oblique cut from the proximal phalanx base starting dorsal distal and ending plantar proximal. We typically remove no more than 4–5 mm as this helps to preserve the plantar intrinsic attachments to improve stability. The hallux is placed through range of motion, and if jamming still occurs, additional bone is removed. But it is important to avoid resecting too much bone as this has been shown to result in worse outcomes [12].

In order to reef the flexor tendon to prevent a floating toe or poor toe purchase, a corkscrew anchor can be placed within the medullary canal of the proximal phalanx , collinear with its longitudinal access. The most common anchor size is 5.5 mm, but the anchor must be large enough so that the threads engage the cortical bone without fracturing the phalanx. The attached nonabsorbable anchor sutures are utilized to grasp the flexor tendon at the level of the first MTPJ and then set aside to hand tie later. In lieu of using an anchor, drill tunnels may be created into the plantar ledge of the remaining proximal phalanx. However, tunneling increases the technical difficulty of the case, and the tunnels are prone to fracture especially in the patient population most suited for this procedure. For this reason, we opt for an anchor as described above as this provides a very strong repair that allows adequate reefing of the flexor tendon which ultimately provides good purchase of the hallux postoperatively.

The “U”-based medial capsulotomy is then prepared for final repair. In order to be able to wrap the capsulotomy around the first metatarsal head, a critical stitch is placed within the plantar lateral capsule next to the first metatarsal head (Fig. 16.4). If the tissue around the plantar lateral first metatarsal head is too weak, an additional small anchor may be added into the plantar lateral first metatarsal head. However, with careful dissection, this anchor is often not required. All of the sutures are placed into the “U” and opposing capsule but not yet tied down. Pop-off sutures can help expedite this process .

To complete the repair, the flexor tendon is first tied down tightly to the proximal phalanx through the use of the proximal phalanx anchor. This will allow the hallux to plantarflex. The capsular repair is then tied down, starting with the plantar lateral stitch first in order to wrap the capsule around the metatarsal head (Fig. 16.5).

Of note, typically less bone resection is required with a hemiarthroplasty than with resection arthroplasty or total joint implants. Care needs to be taken to avoid damaging the insertion of the surrounding soft tissue so to not destabilize the joint. If there is damage, then these structures need to be repaired. It is also important that the appropriately sized implant be used as an implant that is too small may increase the chances of subsidence, fracture, or heterotopic bone formation (Fig. 16.6). The bone surface must be adequately prepared to allow for proper seating of the implant (Fig. 16.7). Final inspection after implant placement should show satisfactory positioning with good coverage of the cortical surfaces both intraoperatively (Fig. 16.8) and on postoperative imaging (Fig. 16.9).