Postoperative Therapy for Metacarpophalangeal Arthroplasty

The purpose of this book was to offer an overview of recent insights into the current state of arthroplasty. The tremendous long term success of Sir Charnley's total hip arthroplasty has encouraged many researchers to treat pain, improve function and create solutions for higher quality of life. Indeed and as described in a special chapter of this book, arthroplasty is an emerging field in the joints of upper extremity and spine. However, there are inborn complications in any foreign design brought to the human body. First, in the chapter on infections we endeavor to provide a comprehensive, up-to-date analysis and description of the management of this difficult problem. Second, the immune system is faced with a strange material coming in huge amounts of micro-particles from the tribology code. Therefore, great attention to the problem of aseptic loosening has been addressed in special chapters on loosening and on materials currently available for arthroplasty.


Introduction
Since the earliest metacarpophalangeal (MCP) arthroplasties in the 1950s, numerous resurfacing and excisional arthroplasties, and a greater choice of surgical tools and techniques to implant the prostheses have become available. Of the excisional arthroplasties, one-piece and two-piece hinge designs, constrained by screws or unconstrained, cemented and non-cemented, have been designed (1) Surgeons now perform these procedures as day surgery, and leave as much original bone as possible in the likelihood of replacing the prosthesis as the patient ages. At the time of surgery, synovectomy and soft-tissue balancing procedures are often performed to increase lateral joint stability or enhance the biomechanical advantage of the tendons around the operated joint. These procedures may necessitate post-operative immobilisation, specific joint positioning and strict motion protocols to achieve the best soft tissue range of motion and stability around the prosthesis (2)(3)(4)(5)(6). The efficacy of postoperative therapy regimens also requires research, as they affect patient outcome, and are time-consuming and expensive. The aim of this review is to determine which postoperative regimen are most effective in achieving freedom from pain and function, and if any particular regimen is best suited to a specific prosthesis or soft-tissue balancing procedure at the time of surgery.

Method
For inclusion in this review, studies had to evaluate the efficacy of a post-arthroplasty regimen for patients who had metacarpophalangeal or joint arthroplasty. Preferred study designs were metanalyses, systematic reviews, and randomised controlled trials, but all published literature except expert opinion was accepted. Patients may have received any type of implant and soft-tissue procedure, due to rheumatoid arthritis, osteoarthritis or trauma. Electronic databases searched were the Cochrane Musculoskeletal Disease Group Register, The Cochrane Library of Systematic review, Google Scholar, and Scopus. Manual searches included of the Journal of Hand Therapy, Hand Therapy and the Journal of Arthroplasty. Search terms in all combinations included 'joint replacement, hand, wrist metacarpophalangeal, arthroplasty, rehabilitation, post-operative, occupational therapy, physical therapy'. The search included papers from 1990 onward, aiming to find research about currently used prostheses and not prostheses of older designs and materials. Studies were appraised as described by the Cochrane Collaboration (7) for sources of methodological bias that could decrease the internal validity of a study. The types of methodological bias were in patient selection, equality of treatment, attrition of patients, and detection of all relevant outcomes. If the study could not be fully appraised from the publication, information was sought by writing to the authors.

Results
Sixteen studies described post-operative therapy for MCP joint replacement in enough detail to understand the treatment schedule. Four hundred and twenty-seven patients in these studies had rheumatoid arthritis, 19 had osteoarthritis and one had psoriatic arthritis. There were four randomised trials (one about post-operative therapy), three prospective cohort studies, three prospective case series (two about post-operative therapy), one case study about post-operative therapy, and the remaining were retrospective case series. Missing data was obtained from two authors, to assist in reviewing the rigour of the studies, but many authors could not be contacted. The randomised controlled trial study found to specifically compare post-operative regimes for metacarpophalangeal arthroplasty (8) randomised patients into postoperative therapy groups that both included dynamic splinting, but the treatment group also included continuous passive motion. These researchers found no difference between treatment groups. Thomsen, Boeckstyns and Leth-Espensen(2003) (9) and retrospectively reviewed consectutive patients who had either dynamic MCP extension splinting, or had static splinting that was removed for exercises post-operatively. They found that residual extension lag was significantly less (p = 0.002) in the dynamicallysplinted group, concluding that postoperative dynamic splinting was useful. Groth, Watkins and Paynter, (1996)(10) retrospectively compared patients who had dynamic flexion with those who had dynamic extension splinting, and found that those who had post-operative dynamic flexion splinting had greater post-operative MCP flexion. Burr, Pratt and Smith (2002)(11), Burr and Pratt (1999) (12) focussed their research on postoperative therapy, but neither study had a comparison treatment group. No further studies compared post-operative treatment regimes, therefore the results of the remaining studies can only be appreciated as a combination of surgery, implant and post-operative therapy. One outcome common to nearly all postoperative patients in every study was the relief of pain once the diseased joint had been removed by surgery. Negative outcomes such as wound infection, implant loosening and migration were reported, in small proportions. Compliance with splinting and therapy was not discussed. Sixteen studies described the outcome of different implants and postoperative therapy regimes for MCP arthroplasty. Features common to many regimens (Table 1) were postoperative avoidance of any hand activity for the first three to six weeks and long-term avoidance of ulnar forces on the fingers. Nearly all regimens began between the second and seventh postoperative day. Regimens could be divided into two main categories with regard to splinting and exercise. Static splint regimens involved removal of the splint for active MCP range of motion exercises, and dynamic splint regimens involved active-assisted MCP extension and active MCP flexion exercises within the splint.

Discussion
Sixteen studies described the outcome of different implants and postoperative therapy regimes for MCP arthroplasty. Two of these studies compared the efficacy of one regimen over another, one of these being prospective. Sambandam, Gul and Priyanka (2007)(25) state that 'most studies undermined the importance of this aspect (post-operative treatment) of the procedure' with regards to first carpometacarpal joint arthroplasty, but their claim could be expanded to arthroplasty of other joints of the hand. Post-operative protocols for splinting, activity and exercises are not always well-described, so although there were numerous studies about MCP arthroplasty, they are not included in this review. Hand therapy for other conditions such as flexor tendon repair also offers multiple postoperative regimens. For example, healing tendons of the hand usually receive motion, but it may be passive, active, or a combination of all of these. The rationale for the various exercise regimens is based on biological healing of the tendon and the strength of the surgical repair, thus its ability to withstand stress without rupturing or gap formation (26,27). These patients usually have normal anatomy preoperatively, leaving few patient variables. Postoperative therapy regimens for MCP arthroplasty are also based on principles of healing and scar formation, but are not prescribed according to the patient's preoperative hand impairment, the type of implant used, or soft tissue balancing procedures performed. For example, patients having undergone extensor tendon rebalancing and recentralization may benefit from avoidance of passive flexion or avoidance of the extremes of flexion, much like a postoperative extensor tendon repair regime. The literature suggests that postoperative therapy for MCP arthroplasty has not been prescribed in this manner; rather, standard protocols have been designed and applied to consecutive patients. To compare the efficacy of a new protocol, many patients would be required for allocation to various postoperative therapy groups. Their outcomes would have to be analyzed according to what protocol they received with the implant, surgery, and preoperative status as variables. The first difficulty in forming control or comparison groups lies in the infrequency of this procedure; for example Ring et al. (8) took three years to include 25 hands in their study. The most common source of bias in the studies was selection bias, which occurs when patients are chosen for treatment or control groups as a result of characteristics that are expected to affect their outcome. Randomization is designed to control the confounding effects of differences between subjects at baseline, and the randomized trial is recommended as the best method of determining treatment efficacy. Here lies the second difficulty in forming control or comparison groups. Patients undergo MCP arthroplasty at all stages of their disease, evidenced by the wide range of motion deficits between the studies of Burr and Pratt, in which the case study patient had nearly normal preoperative MCP motion, and Burr et al., in which some patients had only 25° of MCP flexion, Measures of pain also varied widely in the latter study, ranging from "zero" to "eight out of ten." These baseline measurements demonstrate the difficulty in obtaining a homogeneous, comparable group of patients with rheumatoid arthritis. The other three sources of bias described by the Cochrane Collaboration(7) were present in the reviewed studies. Performance bias occurs when patients receive a variation in duration, www.intechopen.com quality, or quantity of the treatment being studied, which was suspected in the continuous passive motion (CPM) study by Ring et al. Ring et al. describe the application of CPM in detail, except passive forces are described as "low" and treatment quantity is described as "as tolerated." As a result, the reader remains unsure of what amount of passive force is ineffective, as well as what quantity of treatment per day is ineffective. Detection bias is determined if the timing of assessment, the outcome assessment used, or knowledge of the assessor of the patient's previous state could miss any relevant aspect of the outcome. This may have occurred in the study by Groth et al., (10) in which some preoperative data were unavailable and patients were assessed at different postoperative time frames. Detection and comparison of outcomes between studies are only possible when the same outcome measures are used in a standardized manner. The researchers in this review all measured range of motion, but at different time frames (Table 1). Those who measured pain, cosmesis, and function applied different assessments at different time frames. The challenge of outcome measurement in rheumatology has led to the formation of focus groups such as OMERACT (Outcome Measures in Rheumatoid Arthritis Clinical Trials), who have made recommendations for outcome measures to be used in drug trials. OMERACT recommendations are not fully relevant to hand therapy research; however, the process of forming a focus group, and the development of assessment guidelines that allow comparison between homogeneous patients, is possible (28). Attrition bias is determined if the loss of patients in the study is significant or varies between the treatment and control groups. This is common in long-term studies involving patients with rheumatoid arthritis, and was experienced by Groth et al., (10) who were unable to obtain long-term follow-up of the patient group who received their extension protocol. Long-term follow-up is an issue with rheumatoid populations. These patients undergo numerous surgical and drug interventions, while their disease progresses and fluctuates, making the long-term effects of the MCP surgery and therapy difficult to define. Once more, large numbers of patients in each treatment group would be required to decrease the effects of attrition bias and to dilute the effects of subsequent interventions. The difficulties of past studies guide the planning of future studies. Although the issues of low patient numbers, variable preoperative status, additional surgical and drug interventions, and chronic disease cannot be altered, study designs can. Large randomized trials may not be possible; however, samples of patients, paired according to preoperative status, may be allocated to different treatment protocols. Standardized measurement of pain, cosmesis, impairment, disability, and impact on the patient, made at similar postoperative time frames, would further assist in determining treatment efficacy.

Conclusion
This review suggests that all regimens contribute toward an increase in MCP motion and an increase in hand function, but despite the efforts of patients and clinicians, hand therapists remain unaware of the most effective postoperative protocol for MCP arthroplasty or the suitability of each regimen for specific implants and soft-tissue www.intechopen.com procedures. Difficulties in researching this topic include low patient numbers, highly variable preoperative status, lack of guidelines for outcome measures and time frames, and the effects of subsequent interventions received by the patient. The nature and size of the population with rheumatoid arthritis and MCP arthroplasty do not readily fit the randomized, controlled trial design. Paired sample designs are suggested, as well as the formation of standard outcome measures, for better comparison of results between patients. The purpose of this book was to offer an overview of recent insights into the current state of arthroplasty. The tremendous long term success of Sir Charnley's total hip arthroplasty has encouraged many researchers to treat pain, improve function and create solutions for higher quality of life. Indeed and as described in a special chapter of this book, arthroplasty is an emerging field in the joints of upper extremity and spine. However, there are inborn complications in any foreign design brought to the human body. First, in the chapter on infections we endeavor to provide a comprehensive, up-to-date analysis and description of the management of this difficult problem. Second, the immune system is faced with a strange material coming in huge amounts of micro-particles from the tribology code. Therefore, great attention to the problem of aseptic loosening has been addressed in special chapters on loosening and on materials currently available for arthroplasty.