There are three possibilities to approach the proximal interphalangeal joint when planning a PIP arthroplasty: dorsal, volar, and lateral. The chosen incision must respect the complex anatomy of tendons, ligaments, nerves, and vessels surrounding the joint and preserve skin flaps vascularity; it must also allow an early mobilization of the operated joint without the wound itself coming into tension in the postoperative rehabilitation. Whatever access the surgeon prefers, it is advisable to be familiar with the different options available in order to better address specific PIP joint deformities and the possible coexisting problems caused by periarticular soft tissue damage.
Key wordsPIP arthroplasty – PIP surgical approach – PIP joint lesion – finger joint reconstruction – finger joint implants
16 Surgical Approaches for PIP Joint Arthroplasty
The surgical approach to the proximal interphalangeal (PIP) joint matters. The key issue is the complex anatomy of the soft tissues surrounding the joint: the extensor and flexor tendons which are closely related to the articular heads and the ligamentous structures stabilizing the PIP joint. In particular, the extensor apparatus is most critical; it is fragile and very liable to adhesions. The chosen incision must respect the vascularization of the skin flaps; it must also allow an early mobilization of the operated joint without the wound itself coming into tension in the postoperative rehabilitation. There are three possibilities: dorsal, volar (palmar), and lateral.
16.2 Dorsal Approach
This is the most used approach to the PIP joint. It provides safe access and wide exposure to the joint which makes planning easier for the bone cut at implant arthroplasty. Moreover, the alignment and cutting guides for most prostheses are designed for use through a dorsal exposure. 1
16.2.1 Dorsal Skin Incision
The skin incision is most commonly performed following a curved line that does not centrally cross the dorsal aspect of the PIP joint (Fig. 16.1a). This incision is preferred to a central longitudinal rectilinear one in order to reduce the traction on the surgical wound at an early postoperative mobilization. Avoiding skin sutures directly over the extensor apparatus could prevent adhesions with the tendon on the dorsal median line. The skin flap should be sharply elevated, keeping intact the connection between the cutaneous and the subcutaneous fat layer in order to preserve the vascularity of the latter.
16.2.2 Dorsal Tenotomy to the PIP Joint
Once the flap is raised, there are different ways of handling the extensor apparatus. The key question is whether to respect, or not, the insertion of the central band. 2 It may be preserved carrying out an incision either between the transverse retinacular ligament and the volar margin of one of the lateral bands or, alternatively, the incision can be made on the midline, splitting the lateral bands up to the central band. 2 A third option is the Chamay tenotomy; it is carried out by raising a distally based triangular flap extending into the proximal extensor tendon with its apex at the level of the proximal third of the proximal phalanx (Fig. 16.1b). 3 This approach gives a good exposure of the articular surfaces by rotating the tendon flap distally and dislocating the lateral bands volarly when flexing the joint (Fig. 16.1c). The major drawback comes from the intratendinous suture that is needed to relocate the flap; this can be fragile in the early mobilization, with elongation of the tendon scar reducing the function of the extensor mechanism. Yet if immobilized for long it can lead to major adhesions and stiffness.
Other authors prefer to detach the central band from its insertion on the base of middle phalanx obtaining a wide mobilization of the tendon; the tendon can be then fixed back to the base of middle phalanx using transosseous sutures or left unattached where it seems to function well. 2 , 4
16.3 Lateral Approach
The skin incision is performed on the lateral side of the distal half of the proximal phalanx and is then curved dorsally over the middle phalanx (Fig. 16.2a). The skin flap is elevated in order to achieve an adequate exposure of the radial and ulnar aspects of the PIP joint as well as of the extensor apparatus and the flexor sheath (Fig. 16.2b). The neurovascular bundle is protected by the Cleland’s ligament. 2 The retinacular ligament is incised and the lateral band of the extensor tendon is mobilized, while the insertion of the central band is preserved (Fig. 16.2c). The collateral ligament is then elevated as a proximally based triangular flap (Fig. 16.2d, e). This is performed through a V-shaped incision whose longitudinal branch corresponds to the dorsal margin of the collateral ligament, while the anterior-oblique incision separates the collateral and accessory collateral ligaments from the phalangoglenoidal ligament fibers that run obliquely from the base of the middle phalanx (P2) to the lateral margin of the volar plate and the corresponding annular pulley (Fig. 16.2f). 5 The dorsal capsule and the homolateral proximal insertion of the volar plate are then released in order to laterally dislocate the joint with the opposite collateral ligament complex as a pivot point (Fig. 16.2g, h). An ulnar lateral approach is generally preferred, particularly for the index and middle fingers, in order to keep the radial collateral ligament intact so as to maintain stability in pinch with the thumb. 6
As the arthroplasty is completed, the joint is reduced and the collateral ligament complex is sutured back to the phalangoglenoidal fibers (Fig. 16.2i). The extensor apparatus is repaired suturing the retinacular ligament to the lateral band (Fig. 16.2j). Joint stability and passive ranges of motion (ROM) are tested.
The PIP joint is splinted in slight flexion and immediate gentle active joint mobility is allowed. On the third postoperative day a dorsal custom-made static splint is applied, which limits PIP extension to 5 degrees and prevents lateral deviation away from the side of the surgical approach. Four weeks postoperatively, activities of daily living (ADL) are permitted with buddy-taping to the adjacent finger on the side of the approach. 5
16.4 Volar Approach
Schneider 7 described a volar approach in which the pulley system and the volar plate were opened separately. In addition, the main collateral ligament origin had to be released completely. To provide immediate functional rehabilitation with the best possible initial stability, Simmen and Herren 8 , 9 , 10 described a volar approach that leaves the main collateral ligaments intact, and also developed a modified approach to the flexor pulley system and the volar plate.
After a Bruner-type volar incision forming a radially based triangular flap, the two neurovascular bundles are identified and protected (Fig. 16.3a, b). The flexor tendon sheath is opened in the interval between the A2 and the C1 pulleys with incision of the accessory collateral ligaments on either side (Fig. 16.3c). The main collateral ligaments are left intact. The flexor pulley system and the volar plate are then mobilized as a tubular sleeve and retracted to the radial side (Fig. 16.3d, e). The head of the proximal phalanx can be resected, leaving the origins of the main collateral ligaments intact. If necessary, osteophytes at the base of the middle phalanx are also resected. 9 After complete dislocation of the joint, the bone edges can be either remodeled or resected in order to ream the medullary canals and to insert the implant components (Fig. 16.3f). The pulley system with the volar plate is then reattached with a few stitches of resorbable suture material 4–0 or 5–0 (Fig. 16.3g). Functional rehabilitation is started on the first day after the operation, with active flexion and extension exercises three to four times per day. When needed, dynamic splinting is added after 3 to 4 weeks. 9