Endoprothetik des Fingergrundgelenks

Abstract

Only a few of the large number of implants developed during the last decades for replacement of the metacarpophalangeal (MCP) joint have proven to be reliable. The rates of loosening and mechanical failure of almost all types of constrained prostheses are so high that their use cannot be recommended at present. For more than 40 years silicone arthroplasty according to Swanson has been regarded as the gold standard in the prosthetic replacement of the MCP joint. In long-term studies this device provided good pain relief and a lasting correction of preoperative ulnar deviation. The degree of patient satisfaction continues to be high after more than 10 years. With the NeuFlex spacer, a modification of the original Swanson implant, a better range of motion and a reduction of wear-related problems is expected. In this study the results of 130 NeuFlex spacers after a mean time of 3.6 years were examined and 82% of the patients were completely pain free. The mobility of the joints improved from 40 degrees preoperatively to 54 degrees after 3.6 years. Radiologically periprosthetic erosions or osteolyses were seen in approximately 15% of implants. A minimal sinking of the stems developed in 24%, a massive one in 6% and 13% of the spacers were broken. Thus the use of the NeuFlex implant resulted in a better range of motion compared to the Swanson spacer, but the problem of radiological appearance remained unchanged. For unlinked prostheses sufficient soft tissue stability is mandatory as well as wear-resistant surface materials. The pyrocarbon prosthesis according to Beckenbaugh is the only implant for which long-term results are available. In a prospective study we evaluated 28 Ascension pyrocarbon prostheses with a mean follow-up of 4 years. Stability was not found to be a problem. Subjective results were satisfactory, the range of motion remained unchanged, however 46% of prosthesis stems exhibited radiolucent seams, 7 prostheses (25%) were rated as loose and 5 of those had to be replaced by a silicone implant. Use of the implant was abandoned, as it was unreliable regarding bony fixation. There are promising concepts in some new prostheses but independent data are still lacking.

A 10-Year Follow-Up of Uncemented Constrained Metacarpophalangeal Joint Arthroplasties Using the RM Prosthesis in a Patient with Rheumatoid Arthritis.

“…Despite distinctive radiographic loosening and subsidences of all 4 implants, 3 implants are well functioning with a satisfactory outcome in a RA patient with high-demand activities of daily living. This feature (discrepancy between radiographic findings and good subjective results and without necessity of surgical revision in the absence of clinical symptoms) is known from the use of the silicone rubber and pyrocarbon implants [4,6,8,16,17,31]. However, due to the absence of larger case series with long-term follow-up's in the literature, it cannot be concluded that the RM prosthesis is really a reliable option for treatment of RA affecting the MCPJs.…”

“…The constrained MCPJ arthroplasty was designed to decrease the risk of recurrence of palmar (sub) luxation and ulnar deviation postoperatively due to the inherent lack of ligamentous support that was found in up to 31% of patients with RA who underwent a silicone rubber implant arthroplasty [5]. However, the rates of loosening and mechanical failure of almost all types of constrained prostheses are so high that their use cannot be recommended at present [6]; and the role of the piston effect, primarily known from the silicone rubber implant that increases the range of motion of the proximal phalanx , for breakage of prosthesis in cases of loosened nonsilicone uncemented MCPJ implants such as in unconstrained resurfacing pyrocarbon arthroplasty [8,9] or in constrained arthroplasty such as in our following case presentation, is not clearly understood currently. The second generation of the constrained and uncemented MCPJ RM prosthesis (Mathys, Bettlach, Switzerland) is one type that is in use [10].…”

Endoprosthesis of metacarpophalangeal joints of the hand

“…Протез NeuFlex -более современная модель на рынке, созданная в 1998 г. компанией «DePuy» [33][34][35][36][37]. Главной особенностью дизайна стал 30-градусный нейтральный угол, направленный на воссоздание естественной «отдыхающей» позиции руки, что, предположительно, устраняет стрессвоздействие на имплантат, особенно на узловое соединение.…”

“…Примером может служить модель Ascension, показавшая достаточную стабильность, вызвавшая высокую удовлетворенность пациентов, увеличившая средний объем движений и выживаемость. Однако модель была запрещена по двум причинам: 1) из-за низкой костной фиксации и последующей суб люксации; 2) из-за неудовлетворительных рентгенологических показателей (ободок просветления на границе имплантат-кость) [33,39].…”

Structural assessment of pre-flexion in silicone implants for arthroplasty of the first metatarsophalangeal joint

“…10,11 Swanson implants are one of most silicone implants frequently used for joint reconstruction; specifically, for the metacarpophalangeal and metatarsophalangeal joints. 1,6,7,[12][13][14][15][16][17][18][19] Some other implants as Tornier have been created with an axial offset hinge design, which reduces stress on the prosthesis and improves biomechanical function, a characteristic that is not considered in Swanson implants. Moreover, joint flexion for Swanson implant has been measured after implantation finding a mean active and passive arc of motions of 36.80°(SD 19.13) and 46.82° (SD 17.19), respectively.…”