Surgical Technique of a Cement-On-Cement Removal System for Hip and Knee Arthroplasty Revision Surgery

[Tips and tricks of cement removal in the case of revision surgery]

BACKGROUND

In Germany, current revision rates after arthroplasty range between 28-37%. In particular, remaining cement residues are causative for additional revision surgery after periprosthetic joint infection, which is why complete cement removal is of high importance. However, the removal of remaining cement residues often confronts the surgeon with technical challenges. Complication-free and complete cement removal requires extensive preoperative preparation in order to develop the best possible surgical strategy.

TREATMENT

Special instrument sets to facilitate cement removal in revision cases are available from various manufacturers. In addition to endoluminal approaches, access enhancements such as extended osteotomies exist to facilitate complete cement removal. Finally, the surgeon should be able to give the indication for an intraoperative procedural change after a defined time interval.

Frameworks of wavelength selection in diffuse reflectance spectroscopy for tissue differentiation in orthopedic surgery

Significance

Wavelength selection from a large diffuse reflectance spectroscopy (DRS) dataset enables removal of spectral multicollinearity and thus leads to improved understanding of the feature domain. Feature selection (FS) frameworks are essential to discover the optimal wavelengths for tissue differentiation in DRS-based measurements, which can facilitate the development of compact multispectral optical systems with suitable illumination wavelengths for clinical translation.

Aim

The aim was to develop an FS methodology to determine wavelengths with optimal discriminative power for orthopedic applications, while providing the frameworks for adaptation to other clinical scenarios.

Approach

An ensemble framework for FS was developed, validated, and compared with frameworks incorporating conventional algorithms, including principal component analysis (PCA), linear discriminant analysis (LDA), and backward interval partial least squares (biPLS).

Results

Via the one-versus-rest binary classification approach, a feature subset of 10 wavelengths was selected from each framework yielding comparable balanced accuracy scores (PCA: 94.8 ± 3.47 % , LDA: 98.2 ± 2.02 % , biPLS: 95.8 ± 3.04 % , and ensemble: 95.8 ± 3.16 % ) to those of using all features (100%) for cortical bone versus the rest class labels. One hundred percent balanced accuracy scores were generated for bone cement versus the rest. Different feature subsets achieving similar outcomes could be identified due to spectral multicollinearity.

Conclusions

Wavelength selection frameworks provide a means to explore domain knowledge and discover important contributors to classification in spectroscopy. The ensemble framework generated a model with improved interpretability and preserved physical interpretation, which serves as the basis to determine illumination wavelengths in optical instrumentation design.

Restricted Kinematically Aligned Total Knee Arthroplasty Following Failed Oxford Unicompartmental Knee Arthroplasty

In this report, we describe how to revise a failed Oxford unicompartmental knee arthroplasty to kinematically aligned total knee arthroplasty (TKA). Its benefits are the maintenance of the native joint line along with the avoidance of supplemental parts, such as metal augments and stems. This can be applied to patients whose medial tibial cortex is well preserved. The distal cutting plane and rotation alignment are decided before the removal of the femoral component. The tibial cutting plane is up to 12 mm below the lateral joint surface and the varus is up to 5° below the extramedullary rod. Eventually, the native joint line and alignment along with the soft tissue envelope can be well maintained, similar to the restricted kinematically aligned TKA.

Effectiveness and safety of a cement-on-cement removal system for hip and knee arthroplasty revision surgery

Cement removal during hip or knee arthroplasty revision is challenging and not exempt of complications. Cement-on-cement procedure is among techniques developed to safe removal of cement from bone, and it could be a realistic solution. This cement-on-cement devices can provide advantages in removing bone cement during hip and knee arthroplasty septic and non-septic revision surgeries, and can be regarded as an effective and safe alternative. We present our experience using the cement-on-cement technique in 34 cases between 2010 and 2021, including revision surgeries for 20 knee and 14 hip arthroplasties. In 3 out of 34 cases the technique failed, with a success of 91%. Mean surgical time was 2.77 (SD 0.93) hours and blood transfusion was required in 23 cases. Success was achieved in every aseptic case. Of all patients, 60% were septic cases. Infection was considered to be eradicated in 70% (14/20) of patients with a septic revision. Cement-on-cement is a safe and effective alternative for cement removal during hip and knee arthroplasty revision. Level of evidence: III, retrospective case series.

[Strategies for stem revision : Surgery planning, implant removal and reimplantation]

BACKGROUND AND PLANNING

Femoral revision represents a challenging procedure in its surgical planning and technical execution. The results are mainly dependent on the bone loss present, the quality of the implant removal and the choice of revision system. Patient-specific factors such as age, comorbidities, bone quality or even the localization of the cement have a decisive influence on the surgical strategy. Appropriate preoperative preparation, including the presence of the necessary special instruments, which are essential for gentle implant removal, is indispensable to achieve the best possible result.

THERAPY

A bone-sparing implant removal can be particularly challenging, especially in the case of well-fixed stems and cement residues, which may extend far beyond the isthmus. In such situations, a transfemoral approach should be considered. Cementless reimplantation using modular or non-modular titanium stems is currently the preferred treatment of choice for most revisions. In elderly, low-demand patients or with poor bone quality, cemented revision remains a good alternative treatment option.

Comparison of three methods for sealing of the intramedullary femoral canal during total knee arthroplasty; a randomized controlled trial

PURPOSE

The purpose of this randomized controlled study was to examine the effect of sealing the intramedullary canal with a bone or cement plug or leaving it empty on postoperative bleeding and pain MATERIALS AND METHODS: A total of 120 patients with knee osteoarthritis who underwent unilateral TKA participated in the trial and were assigned to one of three groups. The femoral canal was sealed with an autogenous bone plug (Group I) or cement plug (Group II), or it was left open (Group III). Estimated blood loss, Hemoglobin decline, bleeding into the drain, and postoperative pain w compared between groups.

RESULTS

Six patients were excluded due to various reasons, and the remaining 114 patients were included in the final analysis. There were no significant variations in baseline clinical characteristics between the three groups (p > 0.05). Hemoglobin reduction between preoperative and 72 h after the surgery (p: 0.034) and estimated blood loss (p: 0.003) were significantly different between groups. The cement plug group showed the least bleeding. Although there was a significant difference between the cement and empty canal groups (p: 0.03 and p: 0.002, respectively), the difference between the cement and bone groups was similar regarding both hemoglobin reduction and estimated blood loss. The blood volume in the suction drain (p: 0.598) and transfusion rate (p: 0.087) were similar between the groups. VAS at the 12 h after the surgery was similarly high in each group (p: 0.676). It declined at 36 h after surgery, but no significant difference was determined between groups (p: 0.815).

CONCLUSIONS

This study showed that estimated blood loss and hemoglobin reduction were significantly lower in the cement plug group than in the empty canal group. But bone plug group did not show any difference with both empty canal and cement plug groups. Sealing the IM canal or leaving it open did not change the bleeding into the drain, transfusion rate, and postoperative pain between groups. Based on these findings, sealing the IM canal with a cement plug might be recommended to diminish bleeding during TKA despite similar transfusion rates.

LEVEL OF EVIDENCE

Level I, randomized controlled trial.