Distal femoral osteotomy for the valgus knee: indications, complications, clinical and radiological outcome

Outcomes of Medial Closing-Wedge Distal Femoral Osteotomy for Femoral- and Tibial-Based Valgus Deformity

BACKGROUND

In carefully selected patients with an arthritic valgus knee, distal femoral osteotomy (DFO) can improve symptoms at medium- to long-term follow-up, reducing osteoarthritis progression. To date, there is no clear evidence in the current literature regarding the role of postoperative joint line obliquity (JLO) in valgus deformity correction.

PURPOSE

To assess the clinical and radiological outcomes of medial closing-wedge DFO (MCW-DFO) for the treatment of valgus knees, considering both tibial- and femoral-based deformities, as well as to verify the efficacy and safety of MCW-DFO according to JLO boundaries (≤4°).

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective analysis was conducted on a cohort of patients with valgus knees. Patients were divided into 2 groups: femoral-based valgus (FB-V) and tibial-based valgus (TB-V). Knee radiographs were collected before surgery and at the last follow-up. The clinical outcome was evaluated through several validated scores (International Knee Documentation Committee, Knee Society Score, Knee injury and Osteoarthritis Outcome Score, Tegner, Numeric Rating Scale, Crosby-Insall).

RESULTS

A total of 30 patients (34 knees) with a mean age of 49.3 ± 9.1 years were included in the study. The overall mean follow-up was 9.4 ± 5.9 years. The mean preoperative hip-knee-ankle angle was 187.6°± 3.3° (range, 181.5°-191°) and the postoperative angle was 180°± 3.1° (range, 176°-185°). Most postoperative JLOs were within the safe zone of ≤4° in both groups (the postoperative JLO was >4° in 4 patients in the TB-V group and 1 patient in the FB-V group), although FB-V knees exhibited significant superior JLO correction (postoperative JLO in the TB-V group: mean, 4.0°± 2.5° [P = .1]; postoperative JLO in the FB-V group: mean, 2.4°± 1.4° [P = .5]). Significant improvements in all clinical scores were observed in both groups (P < .01). Additionally, the severity of the osteoarthritis did not worsen at the last follow-up.

CONCLUSION

MCW-DFO is an effective procedure for treating pathological valgus knees, regardless of the site of the deformity. Both FB-V and TB-V groups showed comparable improvements in the clinical scores, development of osteoarthritis, and the restoration of a neutral mechanical axis. Notably, FB-V knees achieved more JLO correction compared with the TB-V ones.

Simultaneous Osteosynthesis and Distal Femoral Osteotomy in a Patient With Distal Femoral Fracture Combined With Valgus Knee Deformity: A Case Report

Distal femoral fractures are commonly treated with osteosynthesis. However, in older patients with osteoarthritis of the knee, acute primary total knee arthroplasty (TKA) may be performed to treat these fractures. Notably, no studies have documented the use of osteosynthesis in combination with distal femoral osteotomy (DFO) for treating distal femoral fractures in patients with knee osteoarthritis. This report presents the case of a 66-year-old woman with lateral compartment osteoarthritis accompanied by severe valgus knee deformity who underwent osteosynthesis for a distal femoral fracture combined with medial closing-wedge distal femoral osteotomy (MCWDFO) to correct the knee valgus deformity. She experienced a distal femoral fracture (AO/OTA 33B1.1) of the right knee because of a fall. Before the injury, she exhibited a limp due to severe knee pain with some limitations in knee flexion. Non-weight-bearing radiographs of the entire lower extremity suggested a percentage mechanical axis (%MA) of 115%, indicating severe valgus deformity. On day nine after the injury, we performed osteosynthesis for the distal femoral fracture and conducted an MCWDFO to correct the right knee valgus deformity. After MCWDFO, the %MA was corrected to 70%. Partial weight-bearing was initiated three weeks postoperatively and progressed to full weight-bearing at six weeks. To facilitate bone healing, low-intensity pulsed ultrasound (LIPUS) was applied for three months after surgery. Bone union was successfully achieved by month five. Some medial knee pain persisted for six months after surgery; nonetheless, the patient could walk without a limp. We considered that the integration of MCWDFO with osteosynthesis could provide a treatment option for patients with distal femoral fractures and lateral compartment osteoarthritis.

Patients aged 55 or older undergoing around the knee osteotomy have a higher rate of deep vein thrombosis but not overall early post-operative complications

Purpose

Osteotomies around the knee have been established as an effective method for treating varus or valgus malalignment associated with other knee pathologies in young and middle-aged patients. There is limited literature regarding the risks and complications based on patient age. The purpose of this study is to determine whether age influences as a risk factor for developing intraoperative and early post-operative complications in patients undergoing osteotomies around the knee.

Methods

A consecutive series of patients over 18 years old who underwent distal femoral osteotomy (DFO) or high tibial osteotomy (HTO) with a minimum follow-up period of 90 days were included. Demographic characteristics, surgical technique, intraoperative and post-operative complications up to 90 days were identified. A statistical comparison based on age younger than 55 years or 55 years and older was conducted to determine if patient age acted as a risk factor in the development of complications.

Results

A total of 159 osteotomies were included, of which 129 were HTOs. The average age was 46.16 years, and 118 patients were younger than 55 years. Seven hinge fractures were identified as the only intraoperative complication, while the overall early post-operative complication rate was 11.32%. The most frequent was deep venous thrombosis (DVT) in 5.66% of cases, followed by deep infection with a total rate of 2.52%. When performing the subgroup analysis by age, we observed a significantly higher rate of DVT in the group aged 55 years and older (p 0.036) (odds ratio 3.96 95% confidence interval 1.009-15.533; p 0.048); however, no significant differences were observed in the overall complication rate according to the age group of the patients.

Conclusions

This study reveals that in patients undergoing osteotomies around the knee, the most common post-operative complication was DVT. The rate of DVT was significantly higher in patients aged 55 years and older, although no differences were observed in the overall complication rate according to the patients' age range.

Level of evidence

Level III (retrospective cohort study).

Lateral Opening-Wedge Distal Femoral Osteotomy Made Easy: Tips and Tricks

A lateral opening-wedge distal femoral osteotomy is useful to offload the lateral tibiofemoral compartment for focal chondral defects or isolated lateral compartment arthritis. Although beneficial for these lateral compartment disorders, a distal femoral osteotomy requires careful forethought to optimize correction accuracy and safety. We recommend the following for effective execution of a distal femoral osteotomy: (1) Plan the desired correction preoperatively while accounting for an individual patient's anatomy and femoral width. (2) Perform an iliotibial band Z-lengthening for large deformity corrections to not overconstrain the lateral structures. (3) Use the plate to help guide the level of the osteotomy, which will facilitate bony contact after the osteotomy and decrease plate prominence. (4) Perform the osteotomy with a saw anteriorly and an osteotome posteriorly for safety and stop the osteotomy approximately 1 cm short of the far cortex. (5) Fashion tricortical wedge grafts at the height of the planned correction to maintain reduction and facilitate plate placement. (6) Control the plate position to lie optimally at the level of the osteotomy, ensuring it is not proud and is parallel with the femoral shaft. With these presurgical and intraoperative steps, a lateral opening-wedge distal femoral osteotomy can be performed effectively.