How kinematic disturbance in the deformed rheumatoid thumb impacts on hand function: a biomechanical and functional perspective

Purpose This study investigates the effects of kinematic disturbances in rheumatoid thumb on patient’s hand functions via objective and patient-perceived measurements. Method Twenty-one patients with rheumatoid arthritis (RA) and 21 healthy age- and gender-matched individuals were recruited to receive the objective evaluations, including the Purdue Pegboard Test, Jamar dynamometer, pinch-meter, Permanent Impairment Scale and self-administrated measurements, including the Health Assessment Questionnaire (HAQ) and Manual Ability Measure-36 (MAM-36). An electromagnetic tracking system was used to measure thumb kinematics. The differences in the measures between the RA and control groups and the dominant and non-dominant hands of the RA group were examined. The relationships between the thumb kinematics and hand functional capabilities, as well as impairment levels, were also explored. Results The RA group showed significantly smaller thumb movement capabilities and hand strength, as well as worse scores in hand dexterity, MAM-36 and HAQ than healthy controls. The movement workspace of the RA thumb showed moderate correlations with the factors of hand strength, dexterity, impairment scale, MAM-36 and HAQ scores. Conclusions The findings indicate deficits related to the movement capability of the RA thumb may negatively influence hand dexterity and functional hand performance, as well as life quality, for the patients with RA.

• Implications for Rehabilitation

• A deformed rheumatoid thumb might limit the movement workspace of the thumb and consequently impair the hand performance as well as the life quality.

• The dominant thumb of the RA patients might have greater structural and functional deterioration than the non-dominant side.

• Suitable joint protection strategies, exercises and orthotics should be early applied to the RA patients for preserving hand functions.

     

Functional anatomy of the hand and arm

The physician entrusted with the management of the injured hand must possess knowledge of the functional anatomy of the upper limb. Necessary also is the ability to correlate the surface topography, underlying soft tissues, and the x-ray image as well as the results of individual tests for the functional integrity of skin, vessels, muscle-tendon units, skeleton, joints, and nerves.     

Rehabilitation of the patient with rheumatoid hand involvement

The therapist working with patients with rheumatoid arthritis should consider that they are working with a person with a systemic, chronic disease who may require periodic, long-term treatment. A baseline evaluation helps to establish goals for individual treatment. Reassessment of the patient at various intervals allows the therapist to alter treatment as necessary. In this article, the therapist's role in evaluation and treatment at the various stages of the disease is discussed.     

Reliability,validity, and responsiveness of the modified Kapandji index for assessment of functional mobility of the rheumatoid hand

OBJECTIVE: To determine the reliability, validity, and responsiveness of the modified Kapandji index (MKI). DESIGN: Prospective study. A cohort of patients planned for surgery of the wrist and/or fingers was evaluated within 48 hours before surgery and at least 6 months after surgery. SETTING: Patients were in hospitalized or private care in France. PARTICIPANTS: Patients with rheumatoid arthritis according to criteria of the American College of Rheumatology. Forty-two patients (36 women; mean age, 57.5y; range, 22-80y) were included in the reliability study. Fifty patients (42 women; mean age, 54.18y; range, 19-77y) were included in the validity study. INTERVENTIONS: Not applicable.Main Outcome Measures: Clinical outcome measures included the MKI, the overall mobility score of the wrist and fingers, the finger mobility score, a visual analog scale (VAS) of pain in the hands and wrists, morning stiffness duration, total score of tenderness, total score of swelling, grip and pinch strength, the Hand Functional Index (HFI), and the Cochin rheumatoid hand disability scale. Reliability was studied with the intraclass correlation coefficient (ICC) and the Bland and Altman method. Convergent and divergent validity were assessed with the Spearman correlation coefficient. Responsiveness was assessed by the paired t test, the effect size, and the standardized response mean (SRM). RESULTS: Interobserver reliability was good with an ICC of.90, and the Bland and Altman analysis showed homogeneous distribution of the differences, with no systematic trend. The MKI correlated well with the other mobility measures (HFI, the finger mobility score measured with the finger goniometer), indicating a good convergent validity, and the expected divergent validity with the other outcome measures (grip and pinch strength, total score of swelling, total score of Ritchie Articular Index, Cochin scale, VAS of pain) was observed. The 50 patients in the validity study were evaluated twice, before and after surgery, at a mean interval +/- standard deviation of 7.16+/-2.10 months (range, 6-15mo). Thirty-six patients (72%) were very satisfied or satisfied with the results of surgery, 7 (14%) were not satisfied or dissatisfied, and 7 (14%) were dissatisfied or very dissatisfied. The SRM and effect size values of the MKI were -.19 and -.10, respectively. Individual changes in the score had the best correlation (r(s)=.51) with overall patient satisfaction. CONCLUSIONS: The MKI has excellent validity and reliability. Individual changes in the score are clinically relevant. This index can be used in clinical practice and in therapeutic trials; it needs further study concerning its use for hand surgery.     

Basic principles for the treatment of the rheumatoid hand

This article discusses the overall approach to rheumatoid arthritis patients requiring surgery of the hand. Many rheumato-orthopedic operations do not require the skills of a specially trained orthopedic surgeon. What is essential is familiarity with the basic operative techniques in surgery of the rheumatoid hand. Reduced resistance to infection due to the effects of pharmaceutical agents and the progress of rheumatoid arthritis itself requires particularly delicate treatment of tissue and preventive use of antibiotics.     

肌电假手的功能训练和评定

背景:目前研制的肌电假手控制的灵敏度和准确率欠满意,而且肌电控制假肢的肌肉也易疲劳,影响假手操作。目的:探讨肌电手生物反馈训练的最佳方法及其效果评定。设计:前后对照试验。单位:上海第二医科大学附属瑞金医院康复科、北京假肢厂。对象:北京积水潭医院康复科门诊就诊的上肢截肢后要求装配肌电假手的患者14例,共16只肌电手;男11例,女3例;年龄(25±8.69)岁。方法:肌电手生物反馈训练分为基础电信号训练、视觉反馈训练和日常生活能力(ADL)训练。训练时间为4～6周。主要观察指标:肌电假手功能评定结果。结果:16只肌电手能按照截肢者的意愿开手/闭手和旋腕的动作,完成穿衣、洗漱、进餐、写字等ADL功能。结论:欲使肌电手达到预期设定的目标,训练有两个关键:一是寻找残肢肌肉的最强肌电信号;二是不断强化生物反馈过程,使视觉和肌电手的动作协调自如。     

A biomechanical analysis of the rheumatoid index finger after joint arthroplasty

OBJECTIVE: To determine the mechanisms responsible for the recurrence of ulnar drift after metacarpophalangeal joint arthroplasty in the rheumatoid hand. DESIGN: A three-dimensional biomechanical model of the index finger joints was used to predict the implant loads during several activities of daily living. BACKGROUND: Post-operative clinical evaluation of Sutter metacarpophalangeal prostheses shows a high incidence of fracture and recurrent deformity. METHODS: A six-component force transducer in conjunction with a six-camera motion analysis system were used to obtain kinematic and external loading data from eight patients with rheumatoid arthritis during several simulated activities. These data were used as input into a three-dimensional biomechanical model of the implant and interphalangeal joints of the index finger. Tendon lines of action and moment arms were obtained using a series of MRI scans and CAD modelling techniques. RESULTS: Implant forces were oriented in a radial and dorsal direction to resist the ulnarpalmarly pull of tendons associated with the metacarpophalangeal joint. CONCLUSIONS: The recurrence of ulnar drift is attributable to fatigue failure of the prostheses. After fracture the implant is unable to support the repetitive loading patterns experienced during activities of daily living. RELEVANCE: Understanding the mechanisms responsible for the recurrence of ulnar drift and implant failure is a step towards improving the prosthesis design, surgical procedures and ultimately the patient's prognosis.