Introduction
Osteoarthritis (OA) is the most common debilitating joint disorder worldwide, and its prevalence is likely to increase as life expectancy increases, creating a substantial economic burden. Risk factors such as sex, radiographic features, and scintigraphy have not been specifically associated with the condition. Commonly, patients will report pain, decreased function, deformity, and challenges undertaking simple tasks such as activities of daily living as well as essential occupational tasks.
As patients age, the progressive wear and tear of the cartilage and bone compromise the overall joint integrity. As osteoarthritis develops and progresses, joint reconstruction may become a reasonable option. In this patient population, thumb carpometacarpal (CMC) reconstruction is among the most commonly performed surgeries, and while arthrodesis of the small joints of the hand remains a predictable and durable approach, arthroplasty procedures have become more popular in recent decades.
Osteoarthritis of the Small Joints of the Hand
Preoperative Evaluation
Physical examination starts with careful inspection and palpation of the involved digits. Joint swelling, pain, and instability can be found at the metacarpophalangeal (MCP) joint, the proximal interphalangeal (PIP) joint and the distal interphalangeal (DIP) joint. Inflammation associated with osteoarthritis can produce erythema, warmth, effusion, and soft tissue swelling. A more distinguishing feature is the presence of Bouchard and Heberden nodes at the PIP and DIP, respectively. The range of motion may also be restricted due to concomitant MCP or PIP flexion contracture. Furthermore, the tendon integrity may be compromised, especially of the extensor tendons, with ulnar subluxation at the MCP secondary to failure of the sagittal bands. However, this is more commonly recognized in inflammatory disorders such as rheumatoid arthritis of the hand.
Multiple modalities of imaging can be used to assess osteoarthritis of the small joints of the hand. A 3-view radiograph, including PA, lateral, and oblique angles, are the views preferred for imaging patients suspected of having osteoarthritis of the hand. Computed tomography (CT) and magnetic resonance imaging (MRI) are rarely used for assessment of MCP, PIP, and DIP OA with the possible exception of the CT evaluation of intraarticular fracture malunion or the MRI assessment of articular cartilage. Additionally, radiographic scores do not precisely correlate with clinical evaluation.
Due to the diverse presentation, OA treatment is tailored to specific individual needs. Nonoperative treatment options include education about hand therapy techniques to protect hand joints during activities of daily living. Heat modalities, orthoses, gloves, as well as pharmacological agents such as paracetamol/acetaminophen, nonsteroidal antiinflammatory agents (NSAIDs) and intraarticular corticoid injections , may also be of therapeutic benefit. Kroon et al performed a systematic review and meta-analysis on the topic and found that the data indicated that intraarticular steroid injection might be effective in interphalangeal joint OA, but no compelling evidence has been presented. Similarly, strengthening exercises under the supervision of a hand therapist are commonly prescribed. However, as indicated by Magni et al in a meta-analysis published in 2017, despite low-level evidence that exercise may reduce joint stiffness and pain, there is no definite evidence showing that resistance training carries any substantial benefit on hand OA pain and overall hand joint function.
Distal Interphalangeal Joint Arthrodesis
Indications for DIP joint arthrodesis include pain related to either primary degenerative arthritis or posttraumatic arthritis. Contraindications include active infection or an open wound over the joint, atrophic skin, and digital ischemia. Dickson et al highlight three essential considerations that will help with surgical planning:
- 1.
The angle of arthrodesis – typically no or slight flexion and fixation with a variable pitch compression screw
- 2.
Adequate bone stock
- 3.
Size of the distal phalanx – important when considering compression screw fixation as threads of the variable pitch compression screw are at risk to cut out dorsally, potentially damaging the nail bed and ultimately producing an unsightly nail plate
Fowler et al recommend using Kirschner wires (K-wires) and a single loop of surgical steel wire if the distal phalanx diameter is less than 2 mm larger than the width of the variable pitch compression screw to be used.
Surgical Technique
The procedure can be performed under regional or general anesthesia. Through a skin H incision, the terminal tendon is transversely incised, and the joint is exposed. Using a rongeur or a 2-mm high-speed bur, the articular cartilage is denuded, and a flush contact surface is created. Either K-wires, K-wires with a surgical steel wire loop or a headless variable pitch compression screw ( Fig. 57.1 ) can be used to achieve appropriate fixation. Care is taken to avoid inside-out injury of the nail bed which may lead to nail plate deformity. Complications include infected and aseptic nonunions, nail deformity, and prominent hardware distally at the tip of the finger.
Proximal Interphalangeal Joint Arthrodesis
Indications for PIP arthrodesis include symptomatic idiopathic or posttraumatic osteoarthritis. Contraindications include infection, inadequate bone stock, and poor skin envelope.
Surgical Technique
The procedure can be performed under regional or general anesthesia. A longitudinal skin incision is made on skin and extensor mechanism. The articular surface is visualized and the collateral ligaments released. An oscillating saw is then used to cut the bone just proximal to the condylar flares of the proximal phalanx and just distal to the articular surface of the middle phalanx. Only a very small wafer of bone should be removed from the proximal aspect of the middle phalanx. It is essential to make these cuts perpendicular to the longitudinal axis of the digit to prevent digit angulation.
K-wire figure-of-8 tension band wire technique is generally preferred. The degenerative articular surfaces of the PIP joint are osteotomized. The osteotomy of the middle phalanx articular base is performed perpendicular to the long axis of the bone while the osteotomy of the head of the proximal phalanx is done at a progressive angle (30, 40, 50 or 60 degrees) for the index, long, ring or small fingers, respectively. Two parallel 0.035-inch K-wires are drilled first in a retrograde fashion perpendicular to the osteotomy cut of the proximal phalanx then in an antegrade direction across the osteotomized surface of the middle phalanx. The tips of the K-wires should stop about 5 mm shy of the distal articular aspect of the middle phalanx for later advancement. Once the articular surfaces are stabilized, another 0.035-inch K-wire is drilled transversely to the axis of the middle phalanx through the dorsal cortex at the junction of the proximal and middle thirds of the shaft. A figure-of-8 loop using a 20G surgical steel wire is passed through the drill hole in the middle phalanx shaft then just proximal to the K-wires exiting the proximal phalanx. Next, the exposed K-wires are cut approximately 1 cm superficial to the dorsal cortex of the proximal phalanx and are bent 90 degrees to capture and secure the figure-of-8 wire loop after the wire loop has been tightened down by twisting with a needle driver or needle nose pliers. The twist of the figure-of-8 wire is then cut and gently driven down over the middle phalanx with a small bone tamp and mallet ( Fig. 57.2 ). Complications of the figure-of-8 tension band arthrodesis technique for the PIP joint include nonunion (3%), malunion (1%), hardware prominence (9%), phalangeal fracture, hardware failure, and skin necrosis (3.5%). ,
Proximal Interphalangeal Joint Arthroplasty
According to Zhu et al, replacement arthroplasty aims to eliminate pain, restore motion, and maintain joint stability. If an implant does not recreate normal joint kinematics, it provides no benefit, no matter how anatomically accurate. Implant stability is achieved through appropriate implant design and bone interface, as well as the presence of intact soft tissue structures. PIP joint implant arthroplasty includes silicone spacers and semiconstrained devices such as pyrocarbon implant arthroplasty and metal–plastic surface replacement arthroplasty (SRA).
Silicone PIP joint implant arthroplasty was first introduced by Dr. Albert Swanson in the 1970s. This hinged Silastic implant is designed to act as a spacer, and generally provides excellent pain relief. Yamamoto et al report that in this modality of arthroplasty, using a volar approach, better restoration of motion, less extension lag, and fewer complications were gained when compared to other types of implants or surgical implantation methods. Similar results with Silastic implant arthroplasty have also been shown using either the dorsal or the lateral approaches.
Pyrocarbon implants are nonconstrained and do not allow bony ingrowth. Even though pyrocarbon does not undergo degradation due to cyclic loading and presents high breaking strength, its use remains controversial and overall high complication rates have been observed with its use in the PIP joints with more favorable results from pyrocarbon implants realized in the MCP joints of the hand.
SRA implant arthroplasty ( Fig. 57.3 ) is also a nonconstrained device that was designed by Ronald Linscheid based on his analysis of anthropomorphic data determined from cadaveric specimens. Murray et al followed 47 patients that had 67 prostheses, with a mean follow-up of 8.8 years finding 59/67 joints still in service at follow-up with a cumulative failure rate of 16% at 15–25 years. The authors found no association of failure, radiolucency surrounding the implant or subsidence of the implant whether cement was or was not used. There was also no association of implant failure based on the diagnosis of OA or RA. There were 22 complications among 14 patients. There were no infections. The authors concluded that this modality of arthroplasty is a reliable option to address pain and deformity, both in osteoarthritis and in rheumatoid arthritis.
Indications for PIP joint implant arthroplasty include degenerative or posttraumatic arthritis of the PIP in an elderly, low demand patient who desires to maintain joint motion and reduce pain. Contraindications include poor soft tissue envelope, swan neck or boutonnière deformity, infection, and absence of extensor tendon or collateral ligament integrity.
Surgical Technique
The procedure can be conducted under regional or general anesthesia. A dorsal midline approach allows the extensor mechanism to be incised and retracted according to the technique of Chamay whereby a distally based flap of the extensor mechanism is created at the central slip insertion on the base of the middle phalanx ( Fig. 57.4 ). Alternative approaches favored by some are the volar approach and the lateral approach. Once the joint is exposed, the collateral ligaments are protected, and perpendicular osteotomies are placed just proximal to the proximal phalangeal head articular surface and just distal to the origin of radial and collateral ligaments from the head of the proximal phalanx. A back, camphor cut is also performed on the posterior aspect of the head of the osteotomized proximal phalanx to better accommodate the phalangeal component An osteotomy is performed at the base of the middle phalanx, and it should be no more than 2 mm thick, depending on the preexisting subsidence of the proximal articular surface of the middle phalanx. The most important factor is removal of the proximal and middle phalanx articular surfaces in their entirety, as this can be a source of continued pain. Then, both proximal and middle phalanges are broached to the largest best fit with care taken to prevent implantation of undersized components ( Fig. 57.5 ). Once the joint motion is satisfactory after placement of trial components, the permanent components are chosen. Press fitting of the components is preferred, however cement is considered in overly capacious canals or when a “snug” press fit cannot be achieved.
