The treatment of periprosthetic femur fractures after total knee arthroplasty

Minimally invasive surgery of femoral periprosthetic fractures increases the rate of consolidation and decreases time to bone healing without a higher rate of complications

BACKGROUND

Knee periprosthetic femoral fractures (KPPFF) are becoming more frequent due to the increasing number of arthroplasties and the aging population, for whom maintaining autonomy and function remains a challenge. The use of locking plates has improved functional results and promoted the development of "minimally invasive" surgical (MIS) approaches. Despite the availability of literature comparing between different types of osteosynthesis for KPPFF, there is a paucity of information available on the complications of osteosynthesis using locking plates, depending on the approach. We therefore carried out a retrospective multicenter study (nine centers: Dijon, Grenoble, Lille, Marseille, Nice, Paris, Saint-Étienne, Strasbourg, Colmar) as part of a Symposium of the French Society of Orthopedic Surgery and Traumatology (SOFCOT). Following osteosynthesis of KPPFF by locking plates carried out by a standard approach or by a minimally invasive approach (MIS), the objectives were: (1) to compare the complications, (2) to evaluate whether the radiological and clinical results (rate and time of consolidation, resumption of weight bearing, lack of reduction, postoperative autonomy) were comparable in the two groups.

HYPOTHESIS

The hypothesis was that performing an MIS approach in these indications does not confer more complications than a standard approach, and rather, the MIS approach offers better functional and radiological results.

MATERIAL AND METHOD

Five hundred and seventy-three patients presented with KPPFF over the periods studied (retrospective series from January 2012 to December 2016, then prospective series from January to December 2019). After applying the inclusion criteria (KPPFF by locking plate) and exclusion criteria (tumor context, infectious, intraoperative fractures, fractures on loose prostheses, other osteosynthesis methods, treatment by prosthetic revision, patients under the age of 18, follow-up less than 1-year, incomplete files), a global series of 306 patients was retained. Two groups were created according to the approach performed: a standard approach group (S, n=228) and a minimally invasive approach group (MIS, n=78). The demographic data of the population were recorded, as was the criteria for autonomy (Parker score, place of living). Postoperative complications were sought (infection, mechanical complication, surgical revision). Finally, the radiological and clinical results were evaluated (rate of, and time to consolidation, resumption of weight bearing, lack of reduction, postoperative autonomy).

RESULTS

The comparison of the two subgroups, S and MIS, found complication rates are comparable in the two groups in terms of infections [S group: n=18 (7.9%), MIS group: n=2 (2.6%)], mechanical complications [S: n=23 (10.1%), MIS: n=2 (2.6%)], and surgical revision [S: n=33 (14.5%), MIS: n=7 (8.9%)], and a lack of difference in postoperative autonomy [Parker; S group: 4.7±2.4 (0-9) vs. MIS group: 5±2, 7 (0-9)]. On the other hand, the time to return to weight bearing was shorter in the MIS group [4.3±3.5weeks (0-12) versus 10.1±10.1weeks (0-110), p<0.001]. The rate of nonunion was lower in the MIS group [n=1 vs. n=20, i.e. 1.7% vs. 11.1% (p=0.031)] and the time to consolidation was shorter [7.5±4.3weeks (6-30) versus 15.2±9.4weeks (5-78) (p<0.001)].

CONCLUSION

Performing an MIS approach in the management of KPPFF by locking plate osteosynthesis does not cause any more complications than a standard approach. In addition, higher consolidation rates can be obtained in shorter periods of time. This study suggests that it proposing osteosynthesis using the MIS approach as a primary surgery is a reasonable choice when treatment using locking plates is chosen for a KPPFF, subject to technical expertise.

LEVEL OF EVIDENCE

III; observational study.

Treatment of supracondylar periprosthetic femoral fractures with retrograde intramedullary nailing versus distal femoral plating: A systematic review and meta-analysis of current evidence

BACKGROUND

Supracondylar periprosthetic fractures, when amenable to fixation, can be treated by either retrograde intramedullary nailing (RIMN) or plating. There is paucity of evidence regarding the superiority of one fixation method over the other. This review aims to determine which fixation method leads to better functional outcomes and perioperative complications.

HYPOTHESIS

Superiority of intramedullary nailing in terms of fracture healing and surgical complications when compared to distal femoral plating.

MATERIALS AND METHODS

Using PRISMA guidelines, a systematic search was performed. Studies which reported comparative outcome data following the two interventions were included. Qualitative data analysis and narrative synthesis were reported. Pooled comparisons were conducted when similar quantifiable outcomes were reported in a minimum of three studies.

RESULTS

A total of 151 records were generated by the search. Eight studies met the eligibility criteria so were included in the final analysis. The studies comprised a total of 407 cases, with a follow up period ranging from 1 to 15 years. 252 cases were treated with plate fixation and 155 with RIMN. All studies were mitigated by heterogeneity and methodological limitations. The review showed marked variation in descriptive fracture classifications. Narrative data synthesis was conducted. Although guarded by the methodological limitations of individual studies, outcomes showed that mean time to union was equivalent; 5.88 months for RIMN compared to 6.75 months in plating, standardised mean difference=0.28 (95% CI -0.02-0.58). Similarly, no statistically significant differences were reported between RIMN and plating for deep infection (OR:1.41 95%CI 0.40-5.00) and revision surgery (OR: 0.74, 95%CI 0.39-1.41).

DISCUSSION

Clinical outcomes showed a tendency that favours intramedullary nailing; however, generalisation of results was not possible. Future priority must be awarded to higher quality research in the form of a collaborative multicentre observational studies to delineate appropriate major diagnostic categories, ultimately informing a large comparative trial using condition specific validated outcome measures.

LEVEL OF EVIDENCE

III, meta-analysis.

"Stress taper" fixation increases torsional failure strength in a cadaveric femur model

BACKGROUND

To potentially limit peri-implant fractures our institution commonly implements a "stress-taper" fixation construct in which the screw lengths towards the proximal end of a construct are incrementally decreased, in order to avoid a focal stress-riser when loaded. To assess this construct, we asked: 1) Does the stress taper strategy increase torsional strength than the bicortical locking construct when biomechanically tested in a cadaveric femur model? 2) Does it fail in a less comminuted fracture pattern?

METHODS

Seven matched pairs of cadaveric femora were randomly assigned to one of two distal femur fixation groups: plating with stress taper strategy or bicortical fixation. Specimens were first cyclically loaded, then axially rotated to failure under 800 N of compression. Peak torque at failure, degrees of rotation at failure, and energy to failure were calculated and compared using paired t-tests. Fractures were categorized with the assistance of fluoroscopy according to the Orthopedic Trauma Association classification, 32.

FINDINGS

There was significantly greater peak torque (110.6 ± 49.7 Nm vs. 80.6 ± 35.2 Nm), rotation at failure (23.8 ± 5.3° vs 18.9 ± 4.5°) and energy to failure (25.3 ± 15.7 J vs. 14.1 ± 8.3 J) in the stress-taper group as compared to the bicortical group (p = 0.0424), (p = 0.0213) and (p = 0.0460), respectively. 6/7 fractures in the stress-taper group were classified 32 A1 with 1/7 classified A2. 5/7 fractures in the bicortical group were classified B1 and 2/7 classified A2.

INTERPRETATION

'Stress taper fixation' in distal femurs may be protective against peri-implant fractures compared to traditional bicortical fixation. The 'stress taper' concept can increase torsional failure strength in an in vitro model.

Important Factors for Retrograde Nailing Through Total Knee Arthroplasty: A Cadaveric Study

OBJECTIVES

Evaluate how total knee arthroplasty (TKA) implant design, femoral component size, and preoperative knee range of motion affect retrograde femoral nailing.

METHODS

Cadaveric specimens were prepared for TKA with a single radius (SR) or medial pivot (MP) design and tested with cruciate retaining (CR), cruciate substituting (CS), and posterior stabilizing (PS) 9-mm liners. Knee extension identified the minimum flexion required to pass an opening reamer without impinging on TKA components. The angle between the reamer path and the femoral shaft was calculated from lateral fluoroscopic images.

RESULTS

In SR TKA, the average flexion required was 70, 71, and 82 degrees for CR, CS, and PS, respectively. The required flexion in PS was significantly greater (P = 0.03). In MP TKA, the average flexion required was 74, 84, and 123 degrees for CR, CS, and PS, respectively. The required flexion was significantly greater in CS and PS designs (P < 0.0001). Femoral component size did not affect the minimum flexion required. The entry reamer resulted in 9.2 (SR) and 12.5 (MP) degrees of apex anterior deviation.

CONCLUSIONS

When performing retrograde nailing through either of these TKA designs with a 12-mm opening reamer, at least 70 degrees of knee flexion is required to avoid damage to the polyethylene liner or femoral component. PS implants require significantly more flexion with both TKA designs. Femoral component size did not affect the flexion requirement. Approximately a 10-degree deviation exists between the reamer path and femoral shaft.

Management of periprosthetic fractures of knee arthroplasty with revision surgery

Objective

As periprosthetic knee fractures are becoming common with the increase in incidence of primary and revision total knee arthroplasty, their management and treatment have become important. The current study aims to evaluate the revision knee arthroplasty carried out due to the failure of primary treatment of periprosthetic femoral fractures.

Methods

The study was conducted from May 2012 to September 2019 at Orthopedics department of Xinjiang Medical University; out of 21 patients 11 were women and 10 men aged 44 to 80 (mean, 70.76 ± 8.31) years who underwent revision surgery for periprosthetic fractures of 19 distal femur, 1 patellar, and 1 proximal tibial fracture. Nineteen cases had definite trauma history leading to periprosthetic fracture, and 2 cases had fracture during post-operative functional exercise. All patients had revision surgery with extended stems with either constrained or limited condylar knee prosthesis.

Results

The duration of follow-up averaged 4.3 years. The Hospital for Special Surgery (HSS) knee score before fracture averaged 91 + 7.01 points (89-95 points) and 85.5 + 6.18 points (81-90 points) at the last follow-up. The average range of motion of knee joint before fracture was 115.7 [+7.6] (110 [~126]), and 101.3 [+9.8] (85 [~115]) at the last follow-up. There was no significant statistical difference. No complications such as infection, component loosening or nonunion. 2 patients had lower extremity vein thrombosis.

Conclusion

Revision surgery of the knee for the periprosthetic fractures with proper prosthetic selection can attain good outcomes after primary total knee arthroplasty. Reasonable and correct procedure is the main principle for a successful operation. The benefits and applicability of revision TKA is the reconstructive solution for the issues of prosthetic knee fractures, is highly recommended.

Revision Total Knee Arthroplasty for the Management of Periprosthetic Fractures

Periprosthetic fractures after total knee arthroplasty (TKA) can present reconstructive challenges. Not only is the procedure technically complex, but patients with these fractures may have multiple comorbidities, making them prone to postoperative complications. Early mobilization is particularly beneficial in patients with multiple comorbidities. Certain patient factors and fracture types may make revision TKA the ideal management option. Periprosthetic fractures around the knee implant occur most frequently in the distal femur, followed by the tibia and the patella. Risk factors typically are grouped into patient factors (eg, osteoporosis, obesity) and surgical factors (eg, anterior notching, implant malposition). Surgical options for periprosthetic fractures that involve the distal femur or proximal tibia include reconstruction of the bone stock with augments or metal cones or replacement with an endoprosthesis.

Management of Distal Femur Fractures in Adults: An Overview of Options

Surgical treatment of periarticular and intra-articular fractures of the distal femur pose a significant challenge to the orthopedic surgeon. The primary goal of surgical treatment remains: restoration of the articular surface to the femoral shaft, while maintaining enough stability and alignment to enable early range of motion and rehabilitation. With appropriate surgical planning, these injuries can be managed with a variety of methods and techniques, while taking into account patients' functional goals, fracture characteristics, health comorbidities, bone quality, and risk of malunion and nonunion.

Locked plate versus retrograde intramedullary nail for periprosthetic femur fractures above total knee arthroplasty: a meta-analysis

PURPOSE

Locked plate (LP) and retrograde intramedullary nail (RIN) are the most commonly used treatment options for periprosthetic femur fracture above total knee arthroplasty (TKA). Controversy still exists regarding which is better. Therefore we performed a meta-analysis to compare their clinical results.

METHODS

A comprehensive search was conducted through PubMed, EMBase and the Cochrane Collaboration Library. Six comparative studies (265 patients) were included for the meta-analysis.

RESULTS

No statistically significant differences were found between the LP group and RIN group in terms of six month union rate (OR, 1.19; 95 % CI, 0.52-2.69; P = 0.68), union time (WMD, 0.22; 95 % CI, -0.41 to 0.84; P = 0.50), operation time (WMD, 0.54; 95 % CI, -13.09 to 14.17; P = 0.94) or complication rate (OR, 0.79; 95 % CI, 0.22-2.91; P = 0.73). The LP fixation may have a relatively higher re-operation rate (OR, 5.17; 95 % CI, 1.02-26.27; P = 0.05) compared with RIN. The mean union time was 4.0 months in the LP group and 3.7 months in the RIN group.

CONCLUSION

This meta-analysis found no statistically significant difference in six month union rate, union time, operation time and complication rate between the LP group and RIN group. The RIN fixation may have a potential of lower re-operation rate compared with LP. The mean union time was 4.0 months in the LP group and 3.7 months in the RIN group.