Comparison of two minimally invasive implantation instrument-sets for total knee arthroplasty

Department of Orthopedic Surgery, University Teaching Hospital, Medical University of Innsbruck, Carinagasse 47, 6800 Feldkirch, Austria.
Knee Surgery Sports Traumatology Arthroscopy (Impact Factor: 2.84). 10/2009; 18(3):359-66. DOI: 10.1007/s00167-009-0957-z
Source: PubMed

ABSTRACT Several choices of instrument systems are available for minimally invasive surgical approaches. There are reports that one alternative, the quadriceps sparing, side-cutting instrumentation, results in diminished implantation accuracy. A total of 108 patients were randomized to undergo TKA either using side-cutting implant instrumentation (Group A) or anterior-posterior mini-incision instrumentation (Group B). All TKAs were operated on with a minimal invasive, mini-midvastus surgical approach. 50% of the TKAs were performed with computer-assistance in each cohort. The radiographic parameters, clinical outcomes and knee scores were evaluated preoperatively and 3 months postoperative. In Group B, we found significantly higher accuracy for the mechanical axis of the limb (range +/-3 degrees: Group A 54% versus Group B 89%, p = <0.001), medial proximal tibial angle (range +/-3 degrees: Group A 85% versus Group B 98%, p = <0.027) and tibial slope (range +/-3 degrees: Group A 59% versus Group B 85%, p = <0.007). The application of the navigation system could only significantly reduce outliers (accuracy >3 degrees) in Group B. Clinical outcomes and knee scores were similar in both groups and were not influenced by computer-assistance. Using the anterior-posterior, mini-incision instruments for minimally invasive TKA will lead to higher implantation accuracy when compared to the quadriceps sparing side-cutting instrumentation. The navigation technique could not compensate for shortcomings of the side-cutting instrumentation. The clinical relevance of this study is that the quadriceps sparing side-cutting instrumentation should not be used for TKA because of unacceptable reduced implantation accuracy.

1 Follower
  • [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE: Recently, new custom-fit pin guides in total knee arthroplasty (TKA) have been introduced. Use of these guides may reduce operating time. Use of the guides combined with the absence of intramedullary alignment jigs may lead to reduced blood loss and improved early outcomes. Our aim was to evaluate blood loss and early clinical outcomes in patients undergoing minimally invasive TKA using custom-fit magnetic resonance imaging (MRI)-based pin guides. METHODS: A prospective study in 80 patients was carried out. Patients were divided randomly into 2 equal groups. In one group, intramedullary alignment jigs were used. In the second group, custom-fit MRI-based pin guides were used. All patients received the same cemented posterior-stabilized implant through a mini-midvastus approach. The volume in the drain bottles was recorded after 48 h. Hb loss was estimated by subtracting the postoperative from the preoperative Hb level. Transfusion requirements and surgical time were recorded. Outcome measures were Knee Society Scores (KSS), knee flexion, knee swelling and pain. RESULTS: There was lower mean drainage of blood in the custom-fit group (391 ml vs. 603 ml; p < 0.0001). There was no difference in estimated loss of Hb (3.6 g/dl vs. 4.1 g/dl; n.s.) and in transfusion requirements (7.5 % vs. 10 %; n.s.). Surgical time was reduced in the custom-fit group (12 min less; p = 0.001). KSS measured at week 2, 6 and 12 showed no significant difference between groups. Knee flexion measured on days 7, 10 and at week 6, 12 and knee swelling and pain measured on days 1, 3, 10 and at week 6, 12 showed no significant difference between groups. CONCLUSIONS: Using custom-fit pin guides reduces blood drainage, but not the estimated Hb loss in minimally invasive TKA and does not affect transfusion rate. Surgical time is reduced. There is no effect on the early clinical outcomes. LEVEL OF EVIDENCE: Therapeutic study, Level I.
    Knee Surgery Sports Traumatology Arthroscopy 11/2012; 21(10). DOI:10.1007/s00167-012-2284-z · 2.84 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: Conventional total knee arthroplasty (TKA) and the more recently available computer-navigated total knee arthroplasty (CNTKA) use alternative methods to achieve correct limb alignment. This systematic review was undertaken to assess the safety and effectiveness of CNTKA compared with conventional TKA. METHODS: A systematic search of multiple databases identified relevant randomized controlled trials published to August 2012. Study inclusion was established through application of a predetermined protocol, with independent assessment by two reviewers. RESULTS: Thirty randomized controlled trials were included. The majority of adverse events associated with CNTKA were minor and comparable with those seen with conventional TKA. Conversion to conventional TKA was required in 1% of patients undergoing CNTKA. Thirteen trials reporting on satisfactory post-operative radiological alignment of the mechanical axis in the frontal plane were suitable for meta-analysis, which showed a significant total odds ratio (non-event) of 2.32 (95% confidence interval: 1.77-3.04) in favour of CNTKA (P < 0.00001). Clinical outcomes were comparable between the two techniques, with longer-term follow-up suggesting that CNTKA provided no benefit over conventional TKA in terms of sustained functional improvements. CONCLUSIONS: At present, it is unclear whether the significant improvements shown in radiological outcomes after CNTKA translate to measurable clinical benefits. Although an assumption could be made that an improvement in post-operative alignment should lead to an improvement in patient-related outcomes, the available literature did not clearly show this. Further, long-term trials are required to address this issue.
    ANZ Journal of Surgery 09/2012; 83(1-2). DOI:10.1111/j.1445-2197.2012.06255.x · 1.12 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Patient-specific instrumentation in TKA has the proposed benefits of improving coronal and sagittal alignment and rotation of the components. In contrast, the literature is inconsistent if the use of patient-specific instrumentation improves alignment in comparison to conventional instrumentation. Depending on the manufacturer, patient-specific instrumentation is based on either MRI or CT scans. However, it is unknown whether one patient-specific instrumentation approach is more accurate than the other and if there is a potential benefit in terms of reduction of duration of surgery.
    Clinical Orthopaedics and Related Research 07/2014; 472(10). DOI:10.1007/s11999-014-3784-6 · 2.88 Impact Factor