[Early clinical outcome after navigated total knee arthroplasty. Comparison with conventional implantation in TKA: a controlled and prospective analysis]

Short-term outcome after computer-assisted versus conventional total knee arthroplasty: a randomised controlled trial

PURPOSE

To compare the short-term functional outcome after computer-assisted total knee arthroplasty (TKA) versus conventional TKA.

METHODS

23 men and 67 women aged 48 to 80 years were randomised to undergo (1) conventional TKA using an intramedullary guide, (2) conventional TKA using an extramedullary guide, or (3) computer-assisted TKA. Two senior surgeons performed all the TKAs using the same TKA system and the standard anteromedial arthrotomy with eversion of the patella. Patients were assessed by physiotherapists before and 6 months and 2 years after TKA using the Short Form-36 Health Survey, Oxford Knee Score, and Knee Society Score.

RESULTS

Of the 90 patients, 67 and 70 were assessed at 6 months and 2 years after TKA, respectively. No patient developed deep infection or required revision surgery. Functional outcomes of the 3 groups did not differ significantly at the corresponding follow-ups.

CONCLUSION

Significant improvement in the functional outcome was not shown in patients treated with computer-assisted TKA, compared with conventional TKA. Thus, computer-assisted TKA has limited additional short-term benefits. Further studies with longer follow-up are required to examine the benefits of computer-assisted TKA.

No benefit of patient-specific instrumentation in TKA on functional and gait outcomes: a randomized clinical trial

BACKGROUND

Although some clinical reports suggest patient-specific instrumentation in TKA may improve alignment, reduce surgical time, and lower hospital costs, it is unknown whether it improves pain- and function-related outcomes and gait.

QUESTIONS/PURPOSES

We hypothesized that TKA performed with patient-specific instrumentation would improve patient-reported outcomes measured by validated scoring tools and level gait as ascertained with three-dimensional (3-D) analysis compared with conventional instrumentation 3 months after surgery.

METHODS

We randomized 40 patients into two groups using either patient-specific instrumentation or conventional instrumentation. Patients were evaluated preoperatively and 3 months after surgery. Assessment tools included subjective functional outcome and quality-of-life (QOL) scores using validated questionnaires (New Knee Society Score(©) [KSS], Knee Injury and Osteoarthritis Outcome Score [KOOS], and SF-12). In addition, gait analysis was evaluated with a 3-D system during level walking. The study was powered a priori at 90% to detect a difference in walking speed of 0.1 m/second, which was considered a clinically important difference, and in a post hoc analysis at 80% to detect a difference of 10 points in KSS.

RESULTS

There were improvements from preoperatively to 3 months postoperatively in functional scores, QOL, and knee kinematic and kinetic gait parameters during level walking. However, there was no difference between the patient-specific instrumentation and conventional instrumentation groups in KSS, KOOS, SF-12, or 3-D gait parameters.

CONCLUSIONS

Our observations suggest that patient-specific instrumentation does not confer a substantial advantage in early functional or gait outcomes after TKA. It is possible that differences may emerge, and this study does not allow one to predict any additional variances in the intermediate followup period from 6 months to 1 year postoperatively. However, the goals of the study were to investigate the recovery period as early pain and functional outcomes are becoming increasingly important to patients and surgeons.

LEVEL OF EVIDENCE

Level I, therapeutic study. See the Instructions to Authors for a complete description of levels of evidence.

Functional outcomes following total knee arthroplasty: a randomised trial comparing computer-assisted surgery with conventional techniques

BACKGROUND

A number of trials have shown improved radiological alignment following total knee arthroplasty using computer-assisted surgery (CAS) compared with conventional surgery. Few studies, however, have looked at functional outcomes.

METHODS

We prospectively studied a cohort of 107 patients that underwent TKA by a single surgeon. Patients were randomised into 3 groups: computer-assisted surgery for both the femur and the tibia, intramedullary guides for both the femur and the tibia, and an intramedullary guide for the femur and an extramedullary guide for the tibia. Patients were followed-up post-operatively with the Short Form Health Survey (SF-12) and Oxford Knee Score (OKS) questionnaires.

RESULTS

At a median follow-up of 46 months (range 30-69 months), there was a trend towards higher OKS results in the CAS group, with a mean score of 40.6 in the CAS group compared to 37.6 in the extramedullary group and 36.8 in the intramedullary group. The difference seen in the OKS between CAS and the conventional groups had a significant unadjusted p-value (0.024), and approached significance when adjusted for age and sex (0.054). There was a significant improvement in the OKS when the mechanical axis was within ±3° of neutral, versus those outside this range (median of 41.0 compared to 38.3, p=0.045).

DISCUSSION

This study shows that clinically significant differences are being seen in functional scores of patients treated with CAS versus conventional guides, at medium-term follow up. Our findings reinforce the tenet that a coronal mechanical axis of within 3° of neutral equates to significantly better functional outcomes.

Quality-of-life assessment among patients undergoing total knee arthroplasty in Manaus

OBJECTIVE

this study had the aim of assessing the quality of life among patients undergoing total knee arthroplasty (TKA). For this, the SF-36 and WOMAC questionnaires respectively were used to make comparisons with preoperative values.

METHODS

a prospective observational cohort study was conducted, with blinded analysis on the results from 107 TKAs in 99 patients, between June 2010 and October 2011. The present study included 55 knees/patients, among whom 73% were female and 27% were male. The patients' mean age was 68 years. The SF-36 and WOMAC questionnaires (which have been validated for the Portuguese language) were applied immediately before and six months after the surgical procedure.

RESULTS

the statistical and graphical analyses indicated that the variables presented normal distribution. From the data, it was seen that all the indices underwent positive changes after the surgery.

CONCLUSIONS

despite the initial morbidity, TKA is a very successful form of treatment for severe osteoarthritis of the knee (i.e. more than two joint compartments affected and/or Ahlback classification greater than 3), from a functional point of view, with improvement of the patients' quality of life, as confirmed in the present study. This study presented evidence level IV (description of case series), with analysis on the results, without a comparative study.

Custom-fit minimally invasive total knee arthroplasty: effect on blood loss and early clinical outcomes

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.

Little clinical advantage of computer-assisted navigation over conventional instrumentation in primary total knee arthroplasty at early follow-up

PURPOSE

Even though computer-assisted navigation systems have been shown to improve the accuracy of implantation of components into the femur and tibia, long-term results are lacking and there is little evidence yet that navigation techniques also improve functional outcomes and implant longevity following total knee arthroplasty (TKA). The aim of this study was to summarize and compare the clinical outcomes of total knee arthroplasties (TKAs) performed using navigation-assisted and conventional techniques.

METHODS

The study was conducted according to the guidelines described in the Cochrane Handbook for Systematic Reviews of Interventions and Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statements. Methodological features were rated independently by two reviewers. A meta-analysis of randomized controlled trials (RCTs) or quasi- randomized controlled trials (qRCTs) was carried out to evaluate the efficacy of CAS versus conventional TKA. Data were pooled in fixed and random effects models and the weighted mean difference (WMD) and odds ratio (OR) were calculated. Heterogeneity across studies was determined, and subgroup analyses by the type of navigation system (image-based or image-free navigation system) were conducted.

RESULTS

Twenty-one studies that included 2333 knees were collected from different countries. The surgical time was longer for CN TKA than for the conventional procedure. There was no significant difference in the Knee Society Score between the two groups at the 3-month and 6-month follow-up. The rates of postoperative complications in patients who had CN TKA were similar to those in the patients who had conventional TKA.

CONCLUSION

No significant differences in short-term clinical outcomes were found following TKAs performed with and without computer navigation system. However, there is clearly a need for additional high-quality clinical trials with long-term follow-up to confirm the clinical benefits of computer-assisted surgery.

Does computer-assisted surgery improve postoperative leg alignment and implant positioning following total knee arthroplasty? A meta-analysis of randomized controlled trials?

PURPOSE

Computer-assisted surgery has been proposed as a technique to improve implant alignment during total knee arthroplasty (TKA). However, there is still a debate over the accuracy of placing the femoral and tibial components using computer-assisted systems in TKA. The aim of this study is to establish whether computer-assisted surgery leads to superior mechanical leg axis and implant positioning than conventional technique in patients with primary TKA.

METHODS

Major electronic databases were systematically searched to identify relevant studies without language restriction. A meta-analysis of 41 randomized controlled trials (RCTs) or quasi-RCTs was performed in a random effects model. A subgroup analysis was conducted by type of navigation system to explore the clinical heterogeneity between these trials. The following radiographic parameters were used to compare computer-assisted surgery with conventional technique: (1) mechanical leg axis, (2) femoral component coronal alignment, (3) tibial component coronal alignment, (4) femoral component sagittal alignment, and (5) tibial component sagittal alignment.

RESULTS

For the mechanical leg axis and coronal positioning of femoral and tibial components, there are statistically significant reductions in the number of patients with malalignment in the CAS group if the outlier cutoff value is ±3 or 2° in the coronal and sagittal planes, respectively. Subgroup analysis demonstrates that CT-free navigation systems provide better alignment than conventional techniques in the coronal and sagittal alignment of femoral components within ±3 and 2°. If the outlier cutoff value for the tibial sagittal alignment is ±2°, the outlier percentages are higher in the CT-free navigation group than in the conventional group. However, there was no significant difference in the tibial sagittal alignment at ±3°.

CONCLUSION

Computer-assisted surgery does improve mechanical leg axis and component orientation in TKAs. However, high-quality RCTs are necessary to determine whether surgeons could use computer-assisted techniques to achieve a targeted tibial slope in TKA.

LEVEL OF EVIDENCE

Therapeutic study (Systematic review of Level I/II studies), Level II.

Improved accuracy of alignment with patient-specific positioning guides compared with manual instrumentation in TKA

BACKGROUND

Coronal malalignment occurs frequently in TKA and may affect implant durability and knee function. Designed to improve alignment accuracy and precision, the patient-specific positioning guide is predicated on restoration of the overall mechanical axis and is a multifaceted new tool in achieving traditional goals of TKA.

QUESTIONS/PURPOSES

We compared the effectiveness of patient-specific positioning guides to manual instrumentation with intramedullary femoral and extramedullary tibial guides in restoring the mechanical axis of the extremity and achieving neutral coronal alignment of the femoral and tibial components.

METHODS

We retrospectively reviewed 569 TKAs performed with patient-specific positioning guides and 155 with manual instrumentation by two surgeons using postoperative long-leg radiographs. For all patients, we assessed the zone in which the overall mechanical axis passed through the knee, and for one surgeon's cases (105 patient-specific positioning guide, 55 manual instrumentation), we also measured the hip-knee-ankle angle and the individual component angles with respect to their mechanical axes.

RESULTS

The overall mechanical axis passed through the central third of the knee more often with patient-specific positioning guides (88%) than with manual instrumentation (78%). The overall mean hip-knee-ankle angle for patient-specific positioning guides (180.6°) was similar to manual instrumentation (181.1°), but there were fewer ± 3° hip-knee-ankle angle outliers with patient-specific positioning guides (9%) than with manual instrumentation (22%). The overall mean tibial (89.9° versus 90.4°) and femoral (90.7° versus 91.3°) component angles were closer to neutral with patient-specific positioning guides than with manual instrumentation, but the rate of ± 2° outliers was similar for both the tibia (10% versus 7%) and femur (22% versus 18%).

CONCLUSIONS

Patient-specific positioning guides can assist in achieving a neutral mechanical axis with reduction in outliers.

NAVIGATION IN TOTAL KNEE ARTHROPLASTY

Navigation was the most significant advance in instrumentation for total knee arthroplasty over the last decade. It provides surgeons with a precision tool for carrying out surgery, with the possibility of intraoperative simulation and objective control over various anatomical and surgical parameters and references. Since the first systems, which were basically used to control the alignment of bone cutting referenced to the mechanical axis of the lower limb, many other surgical steps have been incorporated, such as component rotation, ligament balancing and arranging the symmetry of flexion and extension spaces, among others. Its efficacy as a precision tool with an effective capacity for promoting better alignment of the lower-limb axis has been widely proven in the literature, but the real value of optimized alignment and the impact of navigation on clinical results and the longevity of arthroplasty have yet to be established.

Clinical outcome using a ligament referencing technique in CAS versus conventional technique

PURPOSE

Computer-assisted surgery (CAS) for total knee arthroplasty (TKA) has become increasingly common over the last decade. There are several reports including meta-analyses that show improved alignment, but the clinical results do not differ. Most of these studies have used a bone referencing technique to size and position the prosthesis. The question arises whether CAS has a more pronounced effect on strict ligamentous referencing TKAs.

METHODS

We performed a prospective cohort study comparing clinical outcome of navigated TKA (43 patients) with that of conventional TKA (122 patients). Patients were assessed preoperatively, and 2 and 12 months postoperatively by an independent study nurse using validated patient-reported outcome tools as well as clinical examination.

RESULTS

At 2 months, there was no difference between the two groups. However, after 12 months, CAS was associated with significantly less pain and stiffness, both at rest and during activities of daily living, as well as greater overall patient satisfaction.

CONCLUSION

The present study demonstrated that computer-navigated TKA significantly improves patient outcome scores such as WOMAC score (P=0.002) and Knee Society score (P=0.040) 1 year after surgery in using a ligament referencing technique. Furthermore, 91% were extremely or very satisfied in the CAS TKA group versus 70% after conventional TKA (P=0.007).

Imageless navigation system does not improve component rotational alignment in total knee arthroplasty

BACKGROUND

The aim of computer-assisted surgery is to improve accuracy and limit the range of surgical variability. However, a worldwide debate exists regarding the importance and usefulness of computer-assisted navigation for total knee arthroplasty (TKA). The main purpose of this study is to summarize and compare the radiographic outcomes of TKA performed using imageless computer-assisted navigation compared with conventional techniques.

MATERIALS AND METHODS

An electronic search of PubMed, EMBASE, Web of Science, and Cochrane library databases was made, in addition to manual search of major orthopedic journals. A meta-analysis of 29 quasi-randomized/randomized controlled trials (quasi-RCTs/RCTs) and 11 prospective comparative studies was conducted through a random effects model. Additional a priori sources of clinical heterogeneity were evaluated by subgroup analysis with regard to radiographic methods.

RESULTS

When the outlier cut-off value of lower limb axis was defined as ±2° or ±3° from the neutral, the postoperative full-length radiographs demonstrated that the risk ratio was 0.54 or 0.39, respectively, which were in favor of the navigated group. When the cut-off value used for the alignment in the coronal and sagittal plane was 2° or 3°, imageless navigation significantly reduced the outlier rate of the femoral and tibial components compared with the conventional group. Notably, computed tomography scans demonstrated no statistically significant differences between the two groups regarding the outliers in the rotational alignment of the femoral and tibial components; however, there was strong statistical heterogeneity.

CONCLUSIONS

Our results indicated that imageless computer-assisted navigation systems improve lower limb axis and component orientation in the coronal and sagittal planes, but not the rotational alignment in TKA. Further multiple-center clinical trials with long-term follow-up are needed to determine differences in the clinical and functional outcomes of knee arthroplasties performed using computer-assisted techniques.

[Biomedical engineering supports surgical planning and interventions]

Fundamental changes were achieved with the introduction of minimally invasive surgery. In this context, innovations in microtechnology played a significant role in the deployment of new tools. Developments for further integration are still ongoing. Furthermore, decisive progress was made by the timely provision of individual patient data prior to surgery. These comprise imaging data, electrophysiological or functional recordings, and synthetic data gained by modeling and simulation of anatomical or physiological conditions. Aside from the technical aspects of supporting surgery, effective quality management and optimized workflow are essential for therapeutic success. The vision of autonomously operating robots has been dropped in favor of permanently conducted and supervised interventions with the support of intelligent tools for the surgeon. Recent advances in reconstruction and transplantation surgery by tissue engineering and molecular biology are only the beginning of new promising concepts.

Clinical outcome and quality of life after computer-assisted total knee arthroplasty: results from a prospective, single-surgeon study and review of the literature

Despite excellent results, there is a lack of prospective studies analysing functional outcome and quality of life after computer-navigated total knee arthroplasty. Fifty-two patients were investigated before and 6 months after surgery with the OrthoPilot navigation system (Aesculap, Germany). We used the SF-36 Health Survey, the visual analog scale (VAS), the Lequesne score and the Knee Society Score (KSS) for assessment. The operation was carried out by one single surgeon. At follow-up, the study population achieved a significant pain reduction on the VAS from 71 to 21 points, an average decline of the Lequesne score from 16 to 7 points coming along with a significant ascent of the KSS from 84 to 157 points. Concerning the SF-36 Health Survey, most of the patients re-achieved age- and gender-matched scores. Poor results were obtained in patients with multiple comorbidities and a severe flexion contracture preoperative.

Computer-assisted and conventional total knee replacement: a comparative, prospective, randomised study with radiological and CT evaluation

After obtaining informed consent, 80 patients were randomised to undergo a navigated or conventional total knee replacement. All received a cemented, unconstrained, cruciate-retaining implant with a rotating platform. Full-length standing and lateral radiographs and CT scans of the hip, knee and ankle joint were carried out five to seven days after operation. No notable differences were found between computer-assisted navigation and conventional implantation techniques as regards the rotational alignment of the femoral or tibial components. Although the deviation from the transepicondylar axis was relatively low, there was a considerable range of deviation for the tibial rotational alignment. There was no statistically significant difference regarding the occurrence pattern of outliers in mechanical malalignment but the number of outliers was reduced in the navigated group.