Search PubMed⌕ Search

PubMed · 9755763

Computer assisted knee replacement.

Abstract

Accurate alignment of knee implants is essential for the success of total knee replacement. Although mechanical alignment guides have been designed to improve alignment accuracy, there are several fundamental limitations of this technology that will inhibit additional improvements. Various computer assisted techniques have been developed to examine the potential to install knee implants more accurately and consistently than can be done with mechanical guides. For example, computer integrated instrumentation incorporates highly accurate measurement devices to locate joint centers, track surgical tools, and align prosthetic components. Image guided knee replacement provides a three-dimensional preoperative plan that guides the placement of the cutting blocks and prosthetic components. Robot assisted knee replacement allows one to machine bones accurately without the use of standard cutting blocks. The rationale for the development of computer assisted knee replacement systems is presented, the operation of several different systems is described, the advantages and disadvantages of different approaches are discussed, and areas for future research are suggested.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

S L Delp, S D Stulberg, B Davies, F Picard, F Leitner. 1998. Computer assisted knee replacement.. https://doi.org/10.1097/00003086-199809000-00007

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

The computer-assisted sequential lateral soft-tissue release in total knee arthroplasty for valgus knees.

Soft-tissue management is a critical factor in total knee arthroplasty, especially in valgus knees. The stepwise release has been based upon surgeon's experience. Computer-assisted surgery has gained increasing scientific interest in recent times and allows the intraoperative measurement of leg axis and gap size in extension and flexion. We therefore aimed to analyse the effect of sequential lateral soft-tissue release and the resulting change in the a.p. limb axis on the one hand and the tibiofemoral gaps on the other hand in extension as well as in flexion in eight cadaveric knees. Measurements were obtained using a CT-free navigation system. In extension the highest increase compared to the previous release step was found for the first (iliotibial band, P = 0.002), second (popliteus muscle, P = 0.0003), third (LCL, 0.007) and the sixth (entire PCL, P = 0.001) release step. In 90 degrees flexion all differences of the lateral release steps were statistically significant (P < 0.004). Massive progression of the lateral gap in flexion was found after the second (popliteus muscle, P = 0.004) and third (LCL, 0.007) release step. Computer-assisted surgery allows measurement of the effect of each release step of the sequential lateral release sequence and helps the surgeon to better assess the result.

Arthroplasty, Replacement, Knee↗

Isolated patellofemoral osteoarthritis.

Isolated patellofemoral osteoarthritis is now recognised to be more common than previously thought. The features and management are reviewed, including the various surgical options in symptomatic patients. The evidence base for managing patellofemoral osteoarthritis is behind that for the tibiofemoral joint. All treatments are based on uncontrolled observational case series, typically retrospectively reviewed. Fortunately the majority of patients with isolated patellofemoral degenerative changes do not need surgical treatment. Those who are symptomatic can usually be successfully treated with weight loss and quadriceps strengthening exercises.

Arthroplasty, Replacement, Knee↗

Stress analysis of the anterior tibial post in posterior stabilized knee prostheses.

Recent retrieval studies have indicated a high incidence of polyethylene wear on the anterior tibial post caused by impingement. This study investigated the influences of post-cam design features and component alignment on the stress distribution in the anterior tibial post when subjected to the impingement loading. Two three-dimensional finite element models of posterior stabilized knee prostheses were constructed, one with flat on flat (FF) and another with curve on curve (CC) contact surfaces between anterior tibial post and femoral cam. The polyethylene insert was modeled with elastoplastic properties. Nine cases, three hyperextension angles (0 degrees , 5 degrees , and 10 degrees ) combined with three axial tibial rotations (0 degrees , 2.5 degrees , and 5 degrees ) simulating different component alignments were analyzed. A vertical compressive load of 2,000 N and an extension moment of 45 Nm were applied simultaneously. The FF model had larger stress increases than the CC model in both hyperextension and tibial rotation compared with the neutral position. The maximum increase for the FF model was 68% in peak contact stress, 125% in von Mises stress, and 58% in tensile stress in the extreme case of 10 degrees of hyperextension combined with 5 degrees of axial rotation. Stress concentration was found at the anterior corner of the post in the FF model; this was not found in the CC model. The curve on curve design can reduce edge loading on the tibial post, especially during axial tibiofemoral rotation.

Arthroplasty, Replacement, Knee↗