Der Prothesennagel—primär belastungsstabiles Implantat bei peri- und subprothetischen Frakturen des Femurs

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.

[Periprosthetic and interimplant femoral fractures: Biomechanical analysis]

BACKGROUND

The requirements for treatment of femoral fractures are increasing with the rising age of the patients. The aim of this study was to evaluate femoral stiffness and the fracture risk after inserting different implants and implant combinations.

METHODS

A total of 48 cadaveric femors were harvested and 8 groups were randomized on the basis of the bone mineral density (BMD). Different osteosyntheses following prosthetic stem implantation (hip and knee prostheses) were performed and compared with native femurs. All specimens were biomechanically tested in a four-point bending until fracture.

RESULTS

The insertion of a femoral stem decreases the stiffness by approximately 33%. Ipsilateral retrograde nailing reduces the force to failure even more. This instable situation can be stabilized by a lateral locking compression plate. The most stable situation occurred in the presence of two cemented stems.

CONCLUSION

Taken together these results clearly indicate that a hip prosthesis significantly weakens the femur, whereas two stems produce the most stable situation at all. The situation of a hip prosthesis and an retrograde nail should be avoided or covered by a bridging-osteosynthesis. In clinical practice an extramedullary fixation technique for distal femoral fractures should be preferred.

Periprosthetic femoral fractures--incidence, classification problems and the proposal of a modified classification scheme

INTRODUCTION

The increasing incidence of periprosthetic fractures correlates directly with the year-after-year increasing frequency of primary joint replacement surgery. The most common fracture localisation is the femur. The undisputed leader in frequency is the fracture that occurs around a total hip arthroplasty. Unfortunately, no general epidemiologic data exist dealing with exact fracture incidence numbers. Furthermore, existing classifications are lacking important information like time point of fracture occurrence, type of the implanted prosthesis and implantation technique (cemented vs. cementless). Additionally, information about mechanical quality of the bone structure and the fracture type are also missing in part.

METHODS

We scanned the literature for adequate and widely used classifications in the field of hip and knee arthroplasty. In a next step we analyzed those classification systems in order to find out to what extent they are able to describe the specific aspects of the fracture event. Therefore we compared the existing classifications and presented their most relevant emphasis. Furthermore, we looked at our own patient population to evaluate incidence of fracture occurrence over time and percentage of loosened components.

RESULTS

The existing classification systems address themselves specifically to the task of describing fracture localization and to some extent fracture type, or combine these two in order to calculate the possibility of loosening of the implanted prosthesis. Some of the important criteria like mechanical quality of the bone stock, primary implantation technique or time point of the prosthesis loosening (prior to or because of the fracture) remain ignored. The incidence of periprosthetic femur fractures at our department increased approximately 2.5 fold over the past two decades. The risk of suffering from a periprosthetic fracture was substantially higher after THA than after TKA. We observed a loose femoral component of the THA in about 45 % of the cases. Finally, we postulate the application of a modified classification for periprosthetic fractures as an alternative to the already published ones; not only for the femur, but also universally for all joints with an arthroplasty.

CONCLUSION

The classification that is introduced in this study allows, in our opinion, a differentiated reflection of the given post-traumatic pathologic changes and enables the description of the fracture itself according to a generally accepted fracture classification scheme.

Periprosthetic femoral fracture - an interdisciplinary challenge

BACKGROUND

The increasing implantation rates of total hip and knee prostheses have been accompanied by a corresponding rise in periprosthetic fractures (PPF), most often affecting the femur.

METHOD

This review is based on a selective search of the PubMed database for articles in English and German. The search was carried out with a set of pertinent medical subject headings (MeSH) and as a free text search employing a logical combination of search terms (evidence grade III-IV).

RESULTS

Soft-tissue-sparing, stable-angle plate osteosynthesis with a firmly seated implant is a safe treatment of periprosthetic femoral fracture (PPFF). A correct assessment of the stability of the prosthesis is a prerequisite for the success of treatment. A loose prosthesis must be surgically revised, and a failed osteosynthesis can also necessitate revision of the prosthesis. The conservative management of PPFF is generally not indicated, as it has a high complication rate.

CONCLUSION

The treatment of periprosthetic fractures requires competence, not just in osteosynthetic techniques, but also in endoprosthesis implantation and revision. Careful preoperative planning to select the proper treatment is essential, and the necessary equipment must be on hand.

Primary cementless hip arthroplasty as a potential risk factor for non-union after long-stem revision arthroplasty in periprosthetic femoral fractures

PURPOSE

In case of stem loosening in periprosthetic femoral fractures (PPFF), revision arthroplasty should be performed. The first hypothesis of this study was that advanced patient age and female gender shows higher non-union rates. The second hypothesis was that primary cementless arthroplasty is associated with a higher non-union rate compared to cemented primary hip arthroplasty.

METHODS

All PPFF occurring between January 2000 and June 2010 treated by revision arthroplasty were included. Multiple regression analysis was performed to identify independent variables leading to fracture non-union.

RESULTS

Eighty one patients (78 % female) met the inclusion criteria. In 20/81 patients (24.7 %) no adequate fracture healing could be determined on radiographs 12 months after revision surgery. Although age and female gender showed a positive correlation with bony non-union after PPFF as expected, the p-values were not statistically significant. Multiple regression analysis revealed primary cementless prosthesis (p = 0.001) to be the only independent variable associated with non-union.

CONCLUSION

Non-cemented primary prosthesis might be a negative predicting factor for the development of non-union after long-stem revision arthroplasty in PPFF. We therefore recommend the thorough debridement of pannus tissue thus inducing bone healing before the implantation of revision prostheses.

[Patients with periprosthetic femur fractures and consecutive stem replacement. Analysis of survival, complications, and quality of life]

BACKGROUND

The goal of treating proximal periprosthetic femur fractures in geriatric patients is a timely postoperative mobilization. The purpose of this study is to analyze the results after treating our patients by femoral stem exchange irrespective of fixation status. The study included 32 patients (2001-2009; mean age 82 years; Vancouver classification: 12 type B1, 16 type B2, and 4 type C).

METHOD

Ambulatory status and activities of daily living pre- and postoperatively were compared. Retrospective data collection was performed by reviewing patients' charts. By interviewing patients, family members, and family physicians missing information was collected.

RESULTS

A total of 22 patients (69%) achieved their pre-traumatic mobilization level; 22 of 26 patients (85%) were reintegrated into their pre-traumatic environment. A 16% (n=5) complication rate and an 87% 12-month survival rate were calculated.

CONCLUSION

The concept of primary stable periprosthetic fracture care by using a revision prosthetic device potentially reduces complications related to postoperative non-weight-bearing without increasing the complication rate related to a more complex surgical procedure.

Aggressive surgical treatment of periprosthetic femur fractures can reduce mortality: comparison of open reduction and internal fixation versus a modular prosthesis nail

OBJECTIVES

The purpose of this study was to determine if immediate full weightbearing after surgical treatment for periprosthetic femur fractures can decrease perioperative and total mortality.

DESIGN

Retrospective review.

SETTING

Level II trauma center.

PATIENTS

Fifty-two consecutive patients with a periprosthetic femur fracture during a 16-year time period.

INTERVENTION

Comparison of open reduction and internal fixation with a plate (non- or partial postoperative weightbearing) versus stem exchange to a modular prosthesis nail (immediate full postoperative weightbearing).

MAIN OUTCOME MEASUREMENTS

Six-month and total mortality using a Kaplan-Meier survival analysis. An additional matched subanalysis was performed for Vancouver Type B1 fractures.

RESULTS

Patients permitted immediate postoperative full weightbearing had a significantly decreased total (P < 0.001) and 6-month mortality (P = 0.007). Subanalysis of patients with Vancouver Type B1 fractures also showed decrease in mortality, which was significant for total (P < 0.005) but not for 6-month mortality (P = 0.121).

CONCLUSION

Treatment of periprosthetic femur fractures with femoral component exchange to a modular prosthetic nail that allows immediate postoperative full weightbearing may decrease mortality.

[Intramedullary nailing of periprosthetic femoral fractures after revision for total knee endoprosthesis. Treatment of periprosthetic femoral fractures by inserted knee endoprostheis with intramedullary shaft by in situ lengthening of the prosthesis with specially prepared slotted hollow nails]

BACKGROUND

With the increasing number of revision operations after knee replacement a growing incidence of periprosthetic femoral fractures which are difficult to treat is observed.

MATERIAL AND METHODS

This retrospective study describes the operating procedure for osteosynthetic treatment of periprosthetic femoral fractures using a specially made slotted hollow nail which is engrafted with the purpose of in-situ lengthening of the prosthesis and thus becomes stably clamped. From 1999 to 2008 our patients have included 9 who were treated by this method. There were 5 male and 4 female patients with an average age of 63.4 years (range 47–80 years). Prerequisites for the performance of this operation are stability of the prosthesis and knowledge of the type of prosthesis or exact preoperative planning based on CT measurement of the thickness and length relationships.

RESULTS

It was possible to conduct a clinical and radiological follow-up examination of all 9 patients after an average time of 29.1 months (range 10–64 months). In all cases load-bearing stabilization of the fracture was confirmed.

CONCLUSION

In-situ coupling of an endoprosthesis with a slotted hollow nail represents a valuable treatment option for periprosthetic fractures.

Periprosthetic femoral fracture after a well-fixed revision total knee arthroplasty treated with in situ effective lengthening of prosthesis

The increasing number of total knee arthroplasties implies a greater likelihood of periprosthetic fractures and need for successful treatment options. We report a case where in situ effective lengthening of the stem of a well-fixed indwelling prosthesis by a custom-made intramedullary nail with taper-lock coupling provided a successful alternative to the established internal fixation techniques involving prosthesis exchange. We believe that effective lengthening of indwelling prosthesis by a custom-made intramedullary nail is an effective option for treating periprosthetic femoral fractures in selected cases, where an attempt of removing well-fixed implant would result in unacceptable bone loss at the joint level.

[Periprosthetic fractures after total hip arthroplasty : classification, diagnosis and therapy strategies]

The number of periprosthetic fractures following hip replacement is increasing due to longer life expectancy and the rising number of joint replacements. The main causes of periprosthetic fractures include trauma, implant specific factors or loosening of the endoprosthesis. When planning therapy, surgeons should consider specific and general implant- and patient-related risk factors to ensure the best possible treatment. Established classification systems can facilitate preoperative planning. At present, the Vancouver classification system probably comes closest to the ideal, as it considers fracture configuration, stability of the implant and quality of the bone stock. Depending on these factors, therapeutic options include conservative treatment, fracture stabilisation or replacement of the endoprosthesis. The problems associated with periprosthetic fractures of varying etiology and the available treatment options are discussed against the background of the established classification systems.

Treatment of periprosthetic femoral fractures by effective lengthening of the prosthesis

The increasing number of hip and knee arthroplasties implies a greater likelihood of periprosthetic fractures and need for successful treatment options. We asked whether in situ effective lengthening of the indwelling prosthesis by a custom-made slotted hollow intramedullary nail provided a reasonable alternative to the established internal fixation techniques and prosthesis exchange. Between 1994 and 2005, we treated 25 patients (four male and 21 female; average age, 80 years) with a hip or knee periprosthetic fracture using this technique. Preconditions included a well-fixed prosthesis with a conical tip. In 23 hip cases a retrograde femur nail and in two knee fracture cases an antegrade nail were used for in situ lengthening of a femoral hip or knee implant stem. In all 25 cases, we used a preoperatively manufactured custom-made implant; in 20 patients, we recommended immediate mobilization by partial or full weightbearing. Eighteen of 25 patients were followed a minimum of 7 months (mean, 25 months; range, 7-31 months). Three patients died and four were lost to followup. We observed fracture healing in all patients, but one female patient had subsequent prosthesis loosening. The major complication rate was 6% (one of 18). We believe effective lengthening of the indwelling prosthesis by a custom-made slotted hollow intramedullary nail is a reasonable option for treating periprosthetic femoral fractures.

Periprothetische Frakturen bei Patienten mit rheumatoider Arthritis

Postoperative periprosthetic fracture is a rare but serious complication after joint replacement surgery. Due to poor bone quality, multiple joint involvement with the replacement of different joints and considerable comorbidity, the presence of rheumatoid arthritis is associated with a high risk of periprosthetic fractures. For the same reasons, periprosthetic fractures in patients with rheumatoid arthritis can be very difficult to treat, and their management often requires an interdisciplinary approach. On the basis of the current literature, the present work describes different aspects of the epidemiology of periprosthetic fractures, principles of their classification, different treatment options and the results of treatment of these fractures. Special attention is paid to the situation of patients with rheumatoid arthritis.

[Trauma surgery in the elderly]

The indications for the surgical treatment of fractures in elderly patients should consider the individual's general health status, the specific pattern of injury, and the ability of the patient to actively participate in the rehabilitation process. Intramedullary systems are the gold standard for shaft and metaphyseal fractures due to the decreased operative trauma and the possibility of early weight bearing and functional treatment. Minimally invasive locking plate systems can frequently be applied, offer decreased risk of secondary fracture displacement, and have great advantages in the treatment of periprosthetic fractures with firm implants. The possible reasons for falls should be diagnosed in order to allow their prevention. An exact assessment of the severity of osteoporosis in important in allowing adequate treatment for associated pain and for decreasing the risk of future osteoporosis related fractures.