Computer-assisted total knee arthroplasty after prior femoral fracture without hardware removal

Outcomes of Total Knee Arthroplasty in Patients with Prior Hardware: A Case-Control Study Using Handheld Navigation

Presence of hardware in juxta-articular location poses challenge during total knee arthroplasty (TKA). When present in distal femur, it precludes the use of an intramedullary femoral jig during TKA often necessitating removal of hardware leading to prolonged surgery, higher risk of complications, and inferior results. We conducted a case-control study to assess the outcome of TKA among patients with post-traumatic arthritis using a handheld navigation system to perform bone cuts allowing retention of hardware in situ. In 15 patients with post-traumatic arthritis and hardware around the knee (Group A), none or part(s) of hardware were removed while performing TKA. These patients were matched to 15 patients who underwent TKA with handheld navigation for primary OA knee (Group B). The perioperative outcomes assessed were operative time, intraoperative blood loss, length of hospital stay, complications, and 30 days reoperation rate. Clinical outcomes were assessed by using Knee Society Score (KSS) and radiological outcomes using mechanical axis and coronal and sagittal component angles. Mean age of patients at surgery were 65.67 years (Group A) and 66.73 years (Group B). Mean operative time and blood loss were significantly higher in Group A as compared with Group B. At the mean follow-up of 34 months, KSS significantly improved in both the groups. However, there was no statistically significant difference in the clinical and radiological outcomes between the two groups. One patient in Group A developed wound dehiscence and had to undergo debridement and flap coverage within 30 days. The use of navigation helps surgeons in gaining proper limb alignment and implant positioning without complete removal of hardware.

A Successful Case of TKA With Complex Deformity And Retained Hardware Using Computer Navigation

We present a case report of a 60-year-old Caucasian female patient, who had undergone a series of procedures for a periprosthetic (after total hip arthroplasty) Vancouver C type diaphyseal fracture of the right femur (reverse distal femoral locking compression plate [LCP] osteosynthesis, then a corrective osteotomy with another distal femoral LCP osteosynthesis). Subsequently, she developed high-grade osteoarthrosis of the right knee, indicated for a total knee arthroplasty. Considering the extent of previous procedures, which had significantly compromised the bone quality of the femur and therefore increased the risk of a refracture after an eventual hardware removal, we decided to retain the LCP plate. We concluded that the optimal solution would be the use of a computer-navigated total knee arthroplasty. This procedure obviated the need for intramedullary guiding, while ensuring optimal joint alignment. No postoperative complications emerged.

The Use of Computer Navigation and Robotic Technology in Complex Total Knee Arthroplasty

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The potential benefits of computer-assisted surgical (CAS) navigation and robotic total knee arthroplasty (TKA) systems, such as increased reliability of restoring the mechanical axis, fewer outliers, more rapid hospital discharge, less physical therapy requirements, decreased blood loss, and decreased revision rates, have led to their application not only in primary cases but also in complex cases such as preoperative deformity and revision.

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Early evidence demonstrates that CAS navigation may help to improve alignment in complex cases of femoral and tibial deformity and in cases of femoral bowing.

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Data regarding deformity correction with robotic systems are similar to CAS navigation with regard to alignment, but are more limited. There are also scant data regarding revision cases and cases of previous intramedullary canal instrumentation.

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Concerns remain regarding cost, learning curves, and operative times. There are potential long-term cost savings associated with a decrease in revisions and readmissions that require additional investigation.

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Early evidence for the use of these emerging technologies for deformity correction and revision cases is promising, but their impact on long-term functional outcomes remains to be demonstrated. Additional well-designed comparative studies are warranted.

Accelerometer-Based, Computer-Navigated Total Knee Arthroplasty to Correct a Complex Deformity in a Patient With Multiple Hereditary Exostoses

Background

Accelerometer-based computer-assisted navigation systems (ABCANSs) have been shown to improve alignment accuracy in total knee arthroplasty (TKA) and are effective in treating complex extra-articular deformity. We present an ABCANS-assisted TKA performed in a 68-year-old male with end-stage arthritis of the right knee, in the setting of a severe valgus deformity secondary to multiple hereditary exostoses.

Methods

The KneeAlign 2 system (OrthAlign, Inc.; Aliso Viejo, CA) was used to perform the TKA in this clinical scenario, given its functionality, which allows angular correction to be tailored to a given deformity, and its reported accuracy in performance of bony resection in TKA. The patient was prospectively followed up for one year postoperatively. Radiographs, PROMs, and patient satisfaction were reported.

Results

After the ABCANS-assisted TKA, the patient's alignment was improved from 25° to 4° of valgus. His final range of motion was 0-135° without an instability. In addition, the patient reported excellent scores on multiple joint-specific outcome measures, including the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, the Forgotten Joint Score, and the Oxford Knee Score.

Conclusion

This case report illustrates the rationale, technique, and the excellent clinical outcomes achieved in a complex patient with extra-articular deformity using an ABCANS-assisted TKA.

Total Knee Arthroplasty Using Patient-specific Blocks after Prior Femoral Fracture without Hardware Removal

BACKGROUND

The options to perform total knee arthroplasty (TKA) with retained hardware in femur are mainly - removal of hardware, use of extramedullary guide, or computer-assisted surgery. Patient-specific blocks (PSBs) have been introduced with many potential advantages, but their use in retained hardware has not been adequately explored. The purpose of the present study was to outline and assess the usefulness of the PSBs in performing TKA in patients with retained femoral hardware. Materials and.

MATERIALS AND METHODS

Nine patients with retained femoral hardware underwent TKA using PSBs. All the surgeries were performed by the same surgeon using same implants. Nine cases (7 males and 2 females) out of total of 120 primary TKA had retained hardware. The average age of the patients was 60.55 years. The retained hardware were 6 patients with nails, 2 with plates and one patient had screws. Out of the nine cases, only one patient needed removal of a screw which was hindering placement of pin for the PSB.

RESULTS

All the patients had significant improvement in their Knee Society Score (KSS) which improved from 47.0 to postoperative KSS of 86.77 (P < 0.00). The mechanical axis was significantly improved (P < 0.03) after surgery. No patient required blood transfusion and the average tourniquet time was 41 min.

CONCLUSION

TKA using PSBs is useful and can be used in patients with retained hardware with good functional and radiological outcome.

Accuracy of CT-based patient-specific guides for total knee arthroplasty in patients with post-traumatic osteoarthritis

Published clinical trials who studied the accuracy of patient-specific guides (PSG) for total knee arthroplasty exclude patients with articular deformity of the knee joint. We prospectively analysed a series of 30 patients with post-traumatic osteoarthritis of the knee joint with use of PSG. At 1 year post-operative, the achieved biomechanical (HKA) axis and varus/valgus of the femur and tibia components were measured on anterior-posterior (AP) long-standing weight-bearing radiographs. Flexion/extension of the femoral and AP slope of the tibia component was measured on standard lateral radiographs. Percentages >3° deviation of the pre-operative planned HKA axis and individual implant components were considered as outliers. Approved and used implant size, median blood loss (ml) and operation time (min) were obtained from the operation records. Pre- and 1-year post-operative patient-reported outcome measures (PROMs) were performed. Eighty-three per cent of the patients had a HKA axis restored <3° of the pre-operative planned alignment. Varus/valgus outliers were 0.0 and 6.7 % for the femoral and tibial components, respectively. Percentages of outliers of flexion/extension were 36.7 % for the femoral component and 10.0 % for the AP slope of the tibial component. Median blood loss was 300 ml (50-700), while operation time was 67 min (44-144). In 20 % of all cases, the approved implant size was changed into one size smaller. One-year post-operative PROMs improved significantly. We conclude that the accuracy of CT-based PSG is not impaired in patients with post-traumatic osteoarthritis and this modality can restore biomechanical limb alignment.

Computer-navigated minimally invasive total knee arthroplasty for patients with retained implants in the femur

Total knee arthroplasty (TKA) in patients with knee arthritis and retained implants in the ipsilateral femur is a challenge for knee surgeons. Use of a conventional intramedullary femoral cutting guide is not practical because of the obstruction of the medullary canal by implants. Previous studies have shown that computer-assisted surgery (CAS) can help restore alignment in conventional TKA for patients with knee arthritis with retained femoral implants or extra-articular deformity, without the need for implant removal or osteotomy. However, little has been published regarding outcomes with the use of navigation in minimally invasive surgery (MIS)-TKA for patients with this complex knee arthritis. MIS has been proven to provide less postoperative pain and faster recovery than conventional TKA, but MIS-TKA in patients with retained femoral implants poses a greater risk in limb malalignment. The purpose of this study is to report the outcome of CAS-MIS-TKA in patients with knee arthritis and retained femoral implants. Between April 2006 and March 2008, eight patients with knee arthritis and retained femoral implants who underwent the CAS-MIS-TKA were retrospectively reviewed. Three of the eight patients had extra-articular deformity, including two femur bones and one tibia bone, in the preoperative examination. The anteroposterior, lateral, and long-leg weight-bearing radiographs carried out at 3-month follow-up was used to determine the mechanical axis of lower limb and the position of components. The mean preoperative femorotibial angle in patients without extra-articular deformity was 3.8° of varus and was corrected to 4.6° of valgus. With the use of navigation in MIS-TKA, the two patients in this study with extra-articular femoral deformity also obtained an ideal postoperative mechanical axis within 2° of normal alignment. Overall, there was a good restoration of postoperative mechanical alignment in all cases, with a mean angle of 0.4° of varus. No limb malalignment or component malposition was found. In clinical assessments, there were also significant improvements in knee specific scores, functional scores, and motion arc. The results of this study suggest that navigation can help achieve accurate alignment and proper prosthesis positioning in MIS-TKA for patients with retained femoral implants and for whom intramedullary rod guidance is impractical.