[Is distal femoral replacement an adequate therapeutic option after complex fractures of the distal femur?]

Weight-bearing Restrictions after Distal Femur Fractures - Review of Current Literature

The incidence of distal femur fractures increases in the geriatric patient. The primary treatment goal in these fractures is early mobilisation to prevent secondary injuries associated with immobility. In light of the increasing spectrum of therapeutic options for postoperative fracture treatment, including double plating, nail-plate combination and distal femur replacement as postoperative treatments, weight-bearing recommendations are becoming increasingly important. The aim of this study was thus to analyse the weight-bearing recommendations and associated therapy results within the literature of the past 9 years and compare the recommendations to our own approach.

Management of infected extremity endoprostheses: a systematic review

BACKGROUND

Endoprosthetic reconstructions have become increasingly common in the setting of significant bone loss. Indications include revision arthroplasty, trauma, and reconstruction in the setting of primary malignancies or bony metastases. Although the use of endoprostheses has several advantages, they carry a high risk of infection. The purpose of this review is to determine the success rates of surgical management of infected endoprostheses.

METHODS

The authors searched databases for relevant studies and screened in duplicate. Data extracted included overall infection rate, timing of infection, follow-up, isolated pathogen and operative treatment strategy, and subsequent failure rate. The overall quality of the evidence with the Methodological Index for non-randomized studies criteria.

RESULTS

A total of 16 studies and 647 patients met the inclusion criteria. 400 patients had operative management and reported outcomes. Failure rates of patients undergoing debridement, antibiotics, and implant retention (DAIR) were 55.1%. Failure rates of patients who underwent one-stage revision were 45.5%. Failure rates of patients undergoing two-stage revision were 27.3%. Failure occurred at 31.4 months (range, 0-228) postoperatively.

CONCLUSIONS

Rates of periprosthetic joint infection remain high in endoprosthetic reconstructions. Although DAIR procedures were found to have a low success rate, they remain a reasonable option in acute infections given the morbidity of staged revisions. There is a lack of comparative data in the current literature and the heterogeneity and low level of evidence does not allow for between group comparisons of results.

Non-neoplastic indications and outcomes of the proximal and distal femur megaprosthesis: a critical review

Purpose

Megaprosthesis or endoprosthetic replacement of the proximal and distal femur is a well-established modality for treatment of tumors. The indications for megaprosthesis have been expanded to the treatment of some non-neoplastic conditions of the knee and hip, with the severe bone loss associated with failed arthroplasty, communited fractures in the elderly with poor bone quality, and resistant non-union. Th aim of this study is to find out whether megaprosthesis of the knee and hip is successful in the treatment of non-neoplastic condtions. The study comprises a review of the indications, complications, and outcomes of megaprosthesis of the proximal and distal femur in non-neoplastic conditions of the knee and hip joints.

Methods

We extensively reviewed the literature on non-neoplastic indications for megaprosthesis of the proximal and distal femur after performing a detailed search of the Pubmed database using the medical subject heading (MeSH) terms ‘proximal femur replacement’ or ‘distal femur replacement’ and ‘hip or knee megaprosthesis.’ The data obtained after the structured search were entered into a Microsoft Excel spreadsheet. The frequency distribution of the demographic data, indications, complications, and outcome was calculated.

Result

We included ten studies (seven proximal femur replacement and three distal femur replacement) of 245 proximal femur and 54 distal femur mega prostheses for treatment of non-neoplastic conditions. Bone loss in failed arthroplasty, either due to periprosthetic fracture or deep infection, was the most common indication for megaprosthesis. Dislocation was the most common complication after proximal femur megaprosthesis, and infection was the leading cause of complications after distal femur megaprosthesis.

Conclusion

Megaprosthesis for treatment of non-neoplastic conditions around the distal and proximal femur is a viable option for limb salvage, with an acceptable long-term outcome. Although the complications and survival rates of megaprosthesis in non-neoplastic conditions are inferior to a primary arthroplasty of the hip and knee but are comparable or better than the mega prosthetic replacement in the neoplastic conditions. Proximal femoral megaprosthesis has higher dislocation rates and requirement for revision compared to distal femoral megaprosthesis. However, the proximal femoral megaprosthesis has lower rates of infection, periprosthetic fractures, and soft tissue complications, as compared to distal femoral megaprosthetic replacement. Both associated with aseptic loosening but not statistically significant.

A new classification of TKA periprosthetic femur fractures considering the implant type

Background

The treatment aims of periprosthetic fractures (PPF) of the distal femur are a gentle stabilization, an early load-bearing capacity and a rapid postoperative mobilization of the affected patients. For the therapy planning of PPF a standardized classification is necessary which leads to a clear and safe therapy recommendation. Despite different established classifications, there is none that includes the types of prosthesis used in the assessment. For this purpose, the objective of this work is to create a new more extensive fracture and implant-related classification of periprosthetic fractures of the distal femur based on available classifications which allows distinct therapeutic recommendations.

Methods

In a retrospective analysis all patients who were treated in the University Hospital Leipzig from 2010 to 2016 due to a distal femur fracture with total knee arthroplasty (TKA) were established. To create an implant-associated classification the cases were discussed in a panel of experienced orthopaedists and well-practiced traumatologists with a great knowledge in the field of endoprosthetics and fracture care. In this context, two experienced surgeons classified 55 consecutive fractures according to Su et al., Lewis and Rorabeck and by the new created classification. In this regard, the interobserver reliability was determined for two independent raters in terms of Cohen Kappa.

Results

On the basis of the most widely recognized classifications of Su et al. as well as Lewis and Rorabeck, we established an implant-dependent classification for PPF of the distal femur. In accordance with the two stated classifications four fracture types were created and defined. Moreover, the four most frequent prosthesis types were integrated. Finally, a new classification with 16 subtypes was generated based on four types of fracture and four types of prosthesis. Considering all cases the presented implant-associated classification (κ = 0.74) showed a considerably higher interobserver reliability compared to the other classifications of Su et al. (κ = 0.39) as well as Lewis and Rorabeck (κ = 0.31). Excluding the cases which were only assessable by the new classification, it still shows a higher interobserver reliability (κ = 0.70) than the other ones (κ = 0.63 or κ = 0.45).

Conclusions

The new classification system for PPF of the distal femur following TKA considers fracture location and implant type. It is easy to use, shows agood interobserver reliability and allows conclusions to be drawn on treatment recommendations. Moreover, further studies on the evaluation of the classification are necessary and planned.

Short and mid term results of revision total knee arthroplasty with Global Modular Replacement System

BACKGROUND

The original knee megaprostheses with fixed or rotating hinge articulation were custom made and only used for reconstruction of the knee following distal femoral or proximal tibial tumor resections. The aim of the study was to analyze the short- and mid-term results of revision total knee arthroplasty with Global Modular Replacement System (GMRS) used in difficult situations not amenable to reconstruction with standard total knee replacement implants.

MATERIALS AND METHODS

Nine patients (9 knees) were treated with this comprehensive modular implant system, with a mean age of 73.7 years (range 56-83 years) and a mean followup of 5 years (range 3-8 years). Two patients were treated for distal femoral nonunion, five for distal femur periprosthetic fracture and two for periprosthetic joint infection.

RESULTS

The mean Knee Society Score: Knee and functional scores were 77.9 and 40 points, respectively. All demonstrated full extension and flexion was at least 90°. Recurrence of infection was present in one patient. No signs of loosening, dislocation, or implant failure were observed.

CONCLUSIONS

Based on our small series of patients that represent severe cases, GMRS provides relatively good mid-term functional results, pain relief, and good implant survivorship with a low complication rate. This salvage procedure allows elderly, infirm patients to regain early ambulatory ability.