A Unique Pattern of Peri-Prosthetic Fracture Following Total Knee Arthroplasty: The Insufficiency Fracture

Early Femoral Insufficiency Fractures After Primary Total Knee Arthroplasty

Background

Periprosthetic femur fracture following total knee arthroplasty (TKA) is a devastating complication. Although trauma-related periprosthetic femur fractures have been well studied, early atraumatic insufficiency periprosthetic fractures (IPFs) are gaining attention. We present the largest IPF series to date to better understand and prevent this complication.

Methods

A retrospective study of all patients who underwent a revision surgery for periprosthetic fracture within 6 months of primary TKA between 2007 and 2020 was performed. Patient demographics, preoperative radiographs, implant details, and fracture radiographs were reviewed. Alignment measurements and fracture characteristics were assessed.

Results

Sixteen patients met criteria (rate 0.05%), and 11 had posterior-stabilized TKAs. The mean age was 79 years, mean body mass index was 31 kg/m², and 94% (15/16) were female. Seven (47%) patients had a confirmed history of osteoporosis. IPF occurred on average 4 weeks (range, 4 days-13 weeks) after the index TKA. Overall, 12 of 16 (73%) had preoperative valgus deformities, and 11 patients (10 valgus, 1 varus) had preoperative deformities >10 degrees. A characteristic radiographic appearance of femoral condylar impaction and collapse was noted in 12 of 16 cases (75%); 11 of these 12 fractures (92%) involved the unloaded compartment based on preoperative varus/valgus deformity.

Conclusions

Patients who developed IPFs were most commonly elderly, obese women with osteoporosis and severe preoperative valgus deformities. The apparent mechanism of failure was overloading of previously unloaded osteopenic femoral condyle. In high-risk patients, the use of a cruciate-retaining femoral component or a femoral stem for a posterior-stabilized femur may be considered to help avoid this catastrophic complication.

Risk Factors and Preventive Strategies for Perioperative Distal Femoral Fracture in Patients Undergoing Total Knee Arthroplasty

Background and Objectives Perioperative distal femoral fracture is rare in patients undergoing total knee arthroplasty (TKA). In such rare cases, additional fixation might be required, and recovery can be delayed. Several studies have focused on perioperative distal femoral fractures in TKA, but there remains a lack of information on risk factors. The purpose of this study was to investigate risk factors for perioperative distal femoral fractures in patients undergoing TKA and suggest preventive strategies. Materials and Methods: This retrospective study included a total of 5364 TKA cases in a single institution from 2011 to 2022. Twenty-four distal femoral fractures occurred during TKA or within one month postoperatively (0.45%). Patient demographics, intraoperative findings, and postoperative progress were obtained from patient medical records and radiographs. Risk factors for fractures were analyzed using multivariate Firth logistic regression analysis. Results: Although all 24 distal femoral fractures occurred in female patients (24 of 4819 patients, 0.50%), the incidence rate of fracture between male and female patients was not significantly different (p = 0.165). The presence of osteoporosis and insertion of a polyethylene (PE) insert with knee dislocation were statistically significant risk factors (p = 0.009 and p = 0.046, respectively). However, multivariate logistic regression analysis showed that only osteoporosis with bone mineral density (BMD) < -2.8 (odds ratio (2.30), 95% CI (1.03-5.54), p = 0.043) was an independent risk factor for perioperative distal femoral fracture in TKA patients. Conclusions: Our results suggest that osteoporosis with BMD < -2.8 is a risk factor for distal femoral fractures in patients undergoing TKA. In these patients, careful bone cutting, adequate gap balancing, and especially the use of the sliding method for insertion of a PE insert are recommended as preventive strategies.

Nonsurgical management of atraumatic early distal femoral periprosthetic insufficiency fracture after primary total knee arthroplasty, a report of two cases

Periprosthetic distal femoral fractures after primary total knee arthroplasty (TKA) are considered rare; however, they pose a challenge for the treating surgeon, and the management options are mostly surgical (open reduction and internal fixation or revision surgery). We present two female patients who developed atraumatic lateral femoral condyle fractures three weeks after primary TKA; both were treated nonsurgically with acceptable outcomes and patient satisfaction. We believe that nonsurgical management of periprosthetic distal femoral fractures could be an economical solution in selected cases; it also could help maintain the distal femoral bone stock till a revision surgery is performed.

Posterior stabilized total knee arthroplasty increases the risk of postoperative periprosthetic fractures

Background

The Insall-Burstein posterior-stabilized knee design was first developed in 1978 by adding a central cam mechanism to the articular surface geometry of the total condylar prosthesis to correct its problems being not “rolling back”. Since then, the use of posterior-stabilized (PS) implants in total knee arthroplasty (TKA) is becoming increasingly popular. However, one of the main disadvantages of PS designs is related to the amount of bone removed during femoral box osteotomy to create the housing of the PS mechanism, the clinical value of removing more or less bone during primary TKA remains to be fully established. The objective of this study was to compare the incidence of early postoperative periprosthetic fractures in the cruciate retaining (CR) and posterior stabilized (PS) knee prosthesis.

Methods

An institutional high volume arthroplasty unit database was reviewed to identify all patients who sustained a postoperative periprosthetic fracture following primary TKA between January 2014 and May 2018. A retrospective chart review was performed to collect clinical, radiographic, and operative report data. A total of 352 patients with 600 primary TKAs were identified. (300 cases of cruciate retaining TKAs from 178 patients and 300 cases of posterior stabilized TKAs from 174 patients) were retrospectively reviewed.

Results

Eleven patients (1.83%) sustained periprosthetic fractures in the postoperative setting following primary TKA. All of the fractures were located on the femur and were treated surgically. Only one knee (one patient) from the CR group sustained a periprosthetic fracture, while 10 knees (from 10 patients) from the PS group sustained a fracture. The relative risk of sustaining a fracture in the CR group was 0.10 times relative to the PS group (RR   =   0.10, 95% CI 0.0129 – 0.776).

Conclusion

Posterior stabilized total knee arthroplasties (TKAs) significantly increase the risk of periprosthetic fractures in obese Asian patients compared to cruciate retaining TKAs.

Sister, Sister! Siblings With Simultaneous Early Femoral Insufficiency Fractures After Total Knee Arthroplasty

Early periprosthetic fractures after total knee arthroplasty are rare but devastating complications which require revision surgery and lead to poor patient satisfaction. We present 2 siblings who underwent primary total knee arthroplasty on the same day and then both presented 2 weeks after surgery with atraumatic periprosthetic femur fractures. The first patient underwent revision for a cemented distal femoral replacement with stemmed tibial fixation. The second patient underwent an isolated femoral component revision with a stemmed femoral component and distal augment. Histological evaluation identified significant peri-implant osteoporosis. The variation in complexity associated with early periprosthetic femoral insufficiency fractures is highlighted by these 2 cases. Surgeons may consider using stemmed femoral components in similar patients if poor distal femoral bone stock is encountered intraoperatively.

Iliotibial band friction syndrome after knee arthroplasty

Iliotibial band (ITB) friction syndrome is known to be one of the main causes of lateral knee pain related to an overuse injury. In the field of knee arthroplasty, ITB traction syndrome has been reported following guided motion total knee arthroplasty, due to posterior femoral translation and internal tibial rotation during knee flexion. However, ITB friction syndrome following conventional knee arthroplasty has not been reported. This paper reports four cases of this syndrome following conventional knee arthroplasty, mainly caused by an obstruction just under the ITB. Cases 1 and 2 presented extruded cement at the femoral component's lateral side after total knee arthroplasty. Case 3 presented a highly sharp-edged bearing at the lateral compartment after bicompartmental knee arthroplasty. Case 4 presented an osteophyte at the femoral component's lateral side after total knee arthroplasty. Although none of the cases responded well to conservative treatment, ITB friction syndrome was completely relieved just after excising the obstruction. Excision of an obstruction should be considered for ITB friction syndrome caused by obstruction just under the ITB following knee arthroplasty.

Early femoral condyle insufficiency fractures after total knee arthroplasty: treatment with delayed surgery and femoral component revision

Background

Periprosthetic fracture following total knee arthroplasty (TKA) is usually associated with a traumatic event and typically treated with fracture fixation techniques. However, we report on a series of patients with early atraumatic condyle fractures that occurred as a result of insufficiency of the unloaded preoperative femoral condyle treated with delayed reconstruction.

Methods

We retrospectively reviewed a series of 7 patients who sustained femoral condyle fractures following TKA and evaluated risk factors for insufficiency.

Results

There were 6 females and 1 male with an average age of 65.5 (range, 63-75) years and an average body mass index of 29.4 (range, 27-32). Fracture occurred on average 24.9 days from the index surgery and secondary to a low energy mechanism. Five patients had valgus alignment (mean, 15.2°) preoperatively and sustained fracture of the unloaded medial femoral condyle. Two patients had varus alignment (mean, 7.0°) preoperatively and both fractured the unloaded lateral condyle. One patient underwent early intervention requiring distal femoral replacement secondary to femoral bone loss. The remaining 6 patients underwent delayed surgery for an average of 6 weeks to allow for fracture healing followed by femoral component revision. At last follow-up (average, 48.5 months), 1 patient required a tibial component revision; however, no revision of the femoral component was required.

Conclusions

Early femoral condyle insufficiency fractures following TKA may be a risk in females with poor bone quality and preoperative valgus alignment. Delayed surgery and femoral component revision is a treatment strategy that prevented the need for other tertiary reconstruction.