Total knee arthroplasty in valgus knee

Different Deformity Origins and Morphological Features in Subtypes of Valgus Knees: A Radiological Classification System

OBJECTIVE

To analyze the deformity origins and distribution among valgus knees to individualize their morphological features.

METHODS

Radiographic images of 105 valgus knees were analyzed. Long-film radiographs and computed tomography were collected for every knee. A malalignment test was performed on standing long-film radiographs. The hip-knee-ankle angle (HKA), the anatomical lateral distal femoral angle (aLDFA), and the anatomical medial proximal tibial angle (aMPTA) were measured on long-film radiographs. The distal condylar angle and posterior condylar angle on distal femur were further measured on computed tomography scans. The tibial bone varus angle was measured on long-film radiographs as well. All the valgus knees were sorted into different subtypes according to the origins of bony deformity, and the prevalence of each subtype was reported. Finally, to examine the inter-observer reproducibility of this classification system, two observers measured the deformities and did the classification for all the 105 knees independently and then the intraclass correlation coefficient (ICC) was calculated.

RESULTS

Among the 105 knees, 48 knees (45.7%) had apparent deformity from the tibial plateau, and 62 knees (59.0%) had apparent deformity from the supracondylar region of the femur. Eighteen knees (17.1%) had distal condylar angle >7°, among which 11 knees had posterior condylar angle >3° simultaneously. Valgus knees had five subtypes of bone deformity origins-the supracondylar part of the femur, the distal aspect of the lateral femoral condyle, both distal and posterior aspects of the lateral femoral condyle, the tibial plateau, or the metaphyseal segment of the tibia. A valgus knee could be labeled as only one subtype, or a combination of two or more subtypes. Labeling 105 knees with origin of the most severe deformity, the prevalence of each subtype was 40.0%, 5.7%, 9.5%, 28.6%, and 16.2%, respectively. The intra-observer and inter-observer ICC of this classification system was 0.992 and 0.976, respectively.

CONCLUSIONS

Valgus knees can be classified into different subtypes according to deformity origins. This radiological classification system has satisfactory reproducibility. It helps surgeons better individualize morphological features of valgus knees.

The impact of individualized care after artificial knee replacement surgery for patients with valgus deformity of the knee†

Objective

To evaluate the perioperative nursing of total knee arthroplasty for patients with valgus deformity of the knee.

Methods

Seventy-six patients who underwent surgical treatment were enrolled in the study from March 2014 to March 2018. The patients in the control group were treated with routine nursing. The experimental group was treated not only with routine nursing but also with health education, psychological care, family social support, and other nursing intervention. Hospital for special surgery and Pittsburgh sleep quality index were used to evaluate the effect of nursing intervention on patients after operation.

Results

All the index scores of the experimental group were lower than those of the control group (P < 0.05), indicating that the function of the diseased limb and the patient's sleep status improved significantly after the intervention.

Conclusions

Individualized nursing can improve the recovery of limb function and improve the patients’ quality of life. It is very effective for nurses to implement individualized nursing measures for patients after surgery.

Re-revision surgery for re-recurrent valgus deformity after revision total knee arthroplasty in a patient with a severe valgus deformity: A case report

BACKGROUND

A recurrent valgus deformity was a common complication after total knee arthroplasty (TKA) in patients with valgus deformity. However, re-revision surgery for re-recurrent valgus deformity after revision TKA in patients with valgus deformity before primary TKA was uncommon.

CASE SUMMARY

We reported a 72-year-old female patient with two recurrent valgus deformities after TKA for a valgus knee deformity who underwent two revision surgeries to rectify the deformity. In the re-revision surgery, bone defects were successfully reconstructed by the augments and cement in combination with screws and a sleeve. An appropriate neutral alignment of the lower limb was restored by the perfect femoral entry point and the long diaphyseal cementless stem. Adequate fixation of the metaphysis and diaphysis of the femur was obtained by the sleeve and long diaphyseal cementless stem. The patient was pain-free and deformity-free for 2.5 years.

CONCLUSION

The management of bone defects, the choice of the stem and the femoral entry point were of vital importance in the revision or re-revision TKA for a recurrent valgus deformity.

Preoperative radiographic valgus alignment predicts the extent of lateral soft tissue release and need for constraint in valgus total knee arthroplasty

BACKGROUND

In total knee arthroplasty (TKA) for valgus knees, the decision to use a constrained implant is often made intraoperatively depending on the extent of soft tissue releases performed and residual soft tissue imbalance. The purpose of this study is to determine if preoperative radiographic criteria of valgus knees can predict the extent of soft tissue releases required and the level of constraint needed to balance the knee during TKA.

METHODS

A single surgeon's 807 consecutive TKA standing hip-knee-ankle radiographs from 2007-2012 were analyzed. One hundred eighty-seven valgus knees were identified and annotated. Statistical univariate and multivariate analyses were performed for both outcomes, lateral release and articulation, to assess the association with risk factors of gender, age, and preoperative radiographic markers of valgus deformity. A P-value <.05 represented a significant difference between groups.

RESULTS

Use of a constrained articulation was associated with increased valgus deformity (mechanical hip-knee-ankle angle, P < .0001) and extent of lateral soft tissue release (P < .0001). No relationship existed between the use of a constrained articulation and age or gender (P > .05). A preoperative anatomic tibiofemoral valgus angle of >16.8° was associated with the use of a constrained articulation during surgery.

CONCLUSIONS

Our data demonstrate that preoperative radiographic characteristics of the valgus knee can be utilized to predict the extent of lateral soft tissue release and whether a constrained articulation will be required in TKA. This will provide surgeons with useful information to offer accurate preoperative counseling to patients and to ensure that the appropriate prosthetic parts are available during surgery.

Are advanced three-dimensional imaging studies always needed to measure the coronal knee alignment of the lower extremity?

BACKGROUND

Coronal malalignment of the lower extremity is closely related to the onset and progression of osteoarthritis. Restoring satisfactory alignment after tibial osteotomy improves the long-term success of this conservative surgery. The purpose of our study was to determine (1) if there is a difference between two-dimensional (2D) and 3D measurements of the hip-knee-ankle (HKA) angle between the mechanical axes of the femur and the tibia, (2) which parameter most affects 2D-3D HKA measurement, and (3) the percentage of patients who are at risk of error in HKA measurement.

METHODS

We reviewed imaging studies of the consecutive patients referred to us for hip or knee pain between June and October 2013. Patients with previous pelvis or lower extremity surgery were excluded.

RESULTS

In 51 % (95/186) of lower extremities examined, the 3D method showed more valgus than the 2D method, and in 49 % (91/186), the 3D method showed more varus. In 12 % of extremities (23/186), the knee varus or valgus alignment was completely opposite in 3D images compared to 2D images. Having more than 7° of flexum/recurvatum alignment increased error in 2D HKA measurement by 5.7°. This was calculated to be 0.15° per 1° increase in femoral torsion and 0.05° per 1° increase in tibial torsion. Approximately 20 % of patients might be at risk of error in HKA angle measurement in 2D imaging studies.

CONCLUSIONS

Orthopaedic surgeons should assess lower extremity alignment in standing position, with enough exposure of the extremity to find severe alignment or rotational deformities, and consider advanced 3D images of those patients who have them. Otherwise, HKA angle can be measured with good accuracy with 2D techniques.

LEVEL OF EVIDENCE

Level-III diagnostic.

Current surgical strategies for total arthroplasty in valgus knee

The majority of orthopaedic surgeons even currently agree that primary total arthroplasty in valgus knees with a deformity of more than ten degrees may prove challenging. The unique sets of bone and soft tissue abnormalities that must be addressed at the time of the operation make accurate axis restoration, component orientation and joint stability attainment a difficult task. Understanding the specific pathologic anatomic changes associated with the valgus knee is a prerequisite so as to select the proper surgical method, to optimize component position and restore soft-tissue balance. The purpose of this article is to review the valgus knee anatomical variations, to assess the best pre-operative planning and to evaluate how to choose the grade of constraint of the implant. It will also be underlying the up-to-date main approaches and surgical techniques be proposed in the English literature both for bone cuts and soft tissue management of valgus knees.

Evaluation of a new low-dose biplanar system to assess lower-limb alignment in 3D: a phantom study

OBJECTIVE

Knee coronal alignment is routinely assessed on a full-length radiograph of the lower limbs. However, poor positioning of the knee during the procedure affects the accuracy of this kind of measurement, particularly in cases combining knee rotation and flexion. The purpose of this study was to assess the value of a three-dimensional assessment of the hip-knee-ankle (HKA) angle based on a biplanar radiographic system.

MATERIALS AND METHODS

A biplanar slot scanning system was used to take radiographs of three lower-limb synthetic models with similar frontal deviation (5° valgus) but different flexion angulations (0°, 9°, and 18°). Biplane acquisitions were done with lower-limb axial rotations ranging from 20° of internal rotation to 20° of external rotation on each of the lower limb models. Three independent observers performed standard 2D measurements of the HKA angle from each anteroposterior (AP) image and also modeled the lower limb in 3D for each biplane acquisition with dedicated software. The HKA angle was automatically calculated from the 3D models. The results of the 2D and 3D techniques were compared.

RESULTS

Axial rotation provoked 2D HKA measurement errors up to, respectively, 1.4°, 4.7°, and 6.8° for the lower extremities with 0°, 9°, and 18° flexion, while it never affected the 3D HKA measurement for more than 1.5°. Interobserver errors were 0.7° (SD = 0.5°) for the 2D measurements and 0.6° (SD = 0.4°) for the 3D measurements.

CONCLUSIONS

The 3D modeling allows for a more accurate evaluation of coronal alignment compared to 2D, eliminating bias due to wrong knee positioning.

Total knee arthroplasty in severe valgus deformity: interest of combining a lateral approach with a tibial tubercle osteotomy

INTRODUCTION

Among the patients requiring total knee arthroplasty (TKA), approximately 10-15% presents with a valgus deformity (VD). Severely deformed valgus knees represent a surgical challenge. The purpose of this study is to evaluate the results of TKA in grade II and III valgus knee deformities (Ranawat classification), focusing on axis correction, by using a lateral parapatellar capsulotomy combined with tibial tubercle osteotomy.

HYPOTHESIS

The lateral approach in combination with a tibial tuberosity osteotomy is highly beneficial in the treatment of severe valgus knees in patients undergoing primary TKA, for correction of anatomical axis.

PATIENTS AND METHODS

Between January 1995 and December 2001, 33 patients with severe VD, grade II and III, were treated with TKA by one surgeon. Twenty-six patients (19 male, seven female) with mean age of 72 years (57-79) were dealt with a resurfacing posterior stabilized design; whereas in seven cases, a constrained type implant was used. These seven patients were excluded from the study. Two more patients were lost for follow-up and were also excluded. The axis deviation of the remaining 24 patients ranged from 15 to 35 degrees, (average 23°). A lateral parapatellar arthrotomy, in combination with tibial tubercle osteotomy was used. Patients' clinical evaluation - using the International Knee Society (IKS) score - with simultaneous radiological assessment was performed yearly after the operation; and for a mean follow-up time of 11.5 years (8 to 15 years).

RESULTS

The mean IKS score improved from 44 points (34 to 52) preoperatively, to 91 points (68 to 100) postoperatively, at the last follow-up. In terms of alignment parameter, only two knees had a residual valgus deviation greater than 7° (ideal range : 3-7°). One knee exhibited a 9° valgus, and another one 10°, according to anatomical axis measurments. In one case, there was a 5mm proximal migration of the osteotomised tuberosity fragment, due to breakage of the screw. However, the final outcome was not affected. There were no cases of tibial tubercle's non-union; neither of delayed instability.

CONCLUSION

The lateral approach is a useful approach in the treatment of severe valgus knee deformity in patients undergoing primary TKA. Anatomical axis restoration is facilitated, as the contracted structures are easily accessed and, in severe cases, the patellar alignment may be achieved by displacing the osteotomised tubercle. However, careful fixation of the tuberosity is mandatory.

LEVEL OF EVIDENCE

Level IV, prospective study of case series.