Suprakondyläre Femurosteotomien in Kniegelenknähe

Planning of distal femoral osteotomy - antegrade vs. retrograde miniaci method

PURPOSE

The antegrade planning method according to Miniaci was primarily developed for high tibial osteotomies but is also used by several surgeons for planning of distal femoral osteotomies (DFO) in daily clinical practice. Strecker adapted in 2006 the Miniaci method as a retrograde method for planning of DFO. It is not yet known whether there is a difference between the planning methods for correction angles and osteotomy wedge heights in DFO planning.

MATERIALS AND METHODS

Three knee surgeons independently performed DFO planning with the antegrade Miniaci method, the retrograde method and the semiautomated method with the software mediCAD® as a gold standard on 40 anonymized preoperative whole-leg X-rays of patients with a coronal deformity treated with DFO. Subsequently, the difference for correction angles and osteotomy wedge heights between the three methods was analyzed and the interobserver reliability was calculated.

RESULTS

The retrograde method resulted in significantly higher correction angles (+ 1.42° ± 0.55°; p < 0.001) and osteotomy wedge heights (+ 1,36 ± 0.61 mm; p < 0.001) than the antegrade Miniaci methods. A linear regression analysis showed a significant relationship between the extent of coronal deformity and the difference in correction angles between the two methods (p < 0.001, R2 = 0.74). The correction angles determined with the software-based method almost matched the values of the retrograde Miniaci method (mean difference: -0.06° ± 0.37°; p = 0.307). The interobserver reliability was almost perfect for all three techniques (ICC: antegrade: 0.85, retrograde: 0.92, software-based: 0.98).

CONCLUSION

Planning a DFO with the antegrade Miniaci method results in lower correction angles and osteotomy wedge heights than with the retrograde method, which in turn exhibits comparable values to software-based method as gold standard, leading to the risk of undercorrection with the antegrade method. In order to reduce the risk of undercorrection in DFO, the retrograde method appears to be superior.

LEVEL OF EVIDENCE

Level 3 - diagnostic retrospective cohort study.

Biomechanical and radiographic advantages of double-level osteotomy over single-level osteotomy for medial knee osteoarthritis with double-level deformity: A retrospective analysis

BACKGROUND

Double-level osteotomy is hypothesized to provide superior biomechanical outcomes compared to single-level osteotomy for medial knee osteoarthritis with double-level deformity. However, its advantages remain underexplored.

METHODS

This retrospective study analyzed 20 knees treated with medial open wedge high tibial osteotomy alone or combined with lateral closed wedge distal femoral osteotomy. Patients were categorized into three groups: Single-level osteotomy for single deformity, single-level osteotomy for double deformity, and double-level osteotomy for double deformity. Radiographic parameters, including Hip-Knee-Ankle angle, mechanical lateral distal femoral angle, medial proximal tibial angle and joint line convergence angle, and gait biomechanics using nine-axis inertial measurement units were evaluated pre- and postoperatively.

FINDINGS

The postoperative mechanical lateral distal femoral angle was better corrected in the double-level osteotomy for double deformity group compared to the single-level osteotomy for double deformity group (P = 0.012). Peak thigh varus acceleration was significantly reduced in both the double-level osteotomy for double deformity and single-level osteotomy for single deformity groups (P = 0.014), but not in the single-level osteotomy for double deformity group. No significant differences were observed in medial proximal tibial angle among groups.

INTERPRETATION

Double-level osteotomy demonstrated superior biomechanical and radiographic outcomes in medial knee osteoarthritis with double-level deformity, emphasizing its role in mitigating joint line obliquity and in optimizing dynamic knee stability.

Efficacy and Complications of External Fixator-Assisted Correction in Cubitus Varus Deformity

Background

Untreated cubitus varus results in cosmetic deformity as well as posterolateral rotatory instability at the elbow if longstanding. French osteotomy with its modifications is the most commonly done osteotomy and relies on a medial intact hinge and these osteotomies fail to address the lateral prominence. Intraoperative fixator assistance to adjust the translation and fine tune the osteotomy is a novel method to address the lateral prominence. This prospective study analyses the efficacy of the same.

Materials and Methods

A total of 16 consecutive patients presenting with unilateral cubitus varus resulting from mal-united supracondylar fracture of humerus were included. The humero-ulnar angle correction required, size of lateral closing wedge and amount of translation required were calculated. After a lateral surgical approach, one Schanz pin of size 2.5mm-3.5mm depending on age, was passed just above the level of distal humerus physis, lateral to medial; a second pin was inserted in the shaft of humerus, again lateral to medial. Pre-calculated wedge of bone was removed, angular correction as well as translation done; fine tuning of the osteotomy was achieved using fixator assistance. Rotational and hyperextension deformities were corrected simultaneously. Fixation of the osteotomy was done by multiple K wires or plates, depending on the age of the patient.

Observation and Results

The mean carrying angle corrected to 10.4 degrees valgus from a preoperative value of 19.8 degrees varus. The mean humero-ulnar angle corrected to 9.6 degrees valgus from a preoperative value of 19.6 degrees varus. The mean lateral prominence index reduced to - 3.8% from a preoperative value of - 5.5%. The mean cosmetic correction score was 9 (Max 10) from a preoperative value of 1.9. No patient had an 'S' shaped deformity in the operated elbow. No nerve palsies were observed in any of the operated patients.

Conclusions

Fixator assistance during surgery allows angular, translation and rotational control of the fragments to fully correct the deformity. It also allows fine tuning of the osteotomy during surgery.

Morphological analysis of the distal femur as a surgical reference in biplane distal femoral osteotomy

Distal femoral osteotomy (DFO) is performed alone or with high tibial osteotomy (HTO) for patients with osteoarthritis and distal femur deformities. DFO is technically demanding, particularly when creating an anterior flange. Herein, we examined the morphological characteristics of the distal femur based on the cortical shape as a surgical reference for biplanar DFO. Computed tomography images of 50 valgus and 50 varus knees of patients who underwent biplanar DFO or total knee arthroplasty were analyzed. Axial slices at the initial level of the transverse osteotomy in the DFO and slices 10 mm proximal and 10 mm distal to that level were selected. The medial and lateral cortical angles and heights (MCLA, LCLA, MCH, and LCH) were measured on axial slices. Statistical comparisons were performed between the medial and lateral cortices and valgus and varus knees. MCLA and MCH were significantly smaller and lower, respectively, than LCLA and LCH (P < 0.01). The MCLA and MCH of varus knees were significantly smaller and lower, respectively, than those of valgus knees (P < 0.01). Surgeons should carefully observe morphological differences in the distal femur cortex, distinguishing between medial and lateral knees and varus and valgus knees during the creation of the anterior flange in the DFO.

Towards a better understanding of knee angular deformities: discrepancies between clinical examination and 2D/3D assessments

INTRODUCTION

Discrepancy between the clinical examination and the 2D/3D radiographs is a common concern in patients with angular or rotational deformities of the lower limbs, as it may alter clinical judgment and subsequent treatment. The aim was to identify such discrepancies and assess determinants that may contribute to their existence.

MATERIALS AND METHODS

A retrospective chart review was conducted on 329 consecutive patients (658 lower limbs) who underwent physical examination and long-leg biplanar radiographs in our institution between 2013 and 2018 for limb length discrepancy or angular deformity of the knees (varus/valgus). Eleven parameters were measured on 2D and 3D images. 3D measurements were based on standing biplanar X-rays and their 3D reconstructions and were considered the gold standard. Contingency tables and multiple linear regression were used to assess discrepancies between the three modalities and their determinants respectively.

RESULTS

Significant mismatches were found between physical examination and 2D images (1% in varus and 1% in valgus), between physical examination and 3D assessment (1% in varus and 4.6% in valgus) as well as between 2 and 3D assessments (1.9% in varus and 7.6% in valgus). The significant determinants of the mismatch between 2 and 3D modalities were frontal pelvic obliquity, neck shaft angle, knee flexion, femoral torsion, and tibial mechanical angle.

CONCLUSION

In the presence of positional and/or morphological deformities, physical examination and 2D assessment of knee alignment could be biased due to axes projection errors. A better understanding of 3D alignment of the knee as part of the entire lower limb from pelvis to toes, may lead to a better diagnosis and subsequently a better treatment of knee angular deformities.

In closed wedge distal femur osteotomies for correction of valgus malalignment overcorrection of mLDFA should be avoided

PURPOSE

The purpose of the study was to investigate the influence of the mLDFA (mechanical lateral distal femur angle) as a parameter in varus realignment osteotomies for valgus deformities of the knee. We hypothesized that joint line obliquity with mLDFA > 90° after distal femur osteotomy (DFO) is associated with inferior clinical outcome.

METHODS

In a retrospective study, a total of 52 patients with isolated femoral valgus deformities were included in the study. The mean postoperative follow-up was 70.5 (SD 33.3) months (standard deviation SD±33.3). In all patients, a distal femur osteotomy was performed. A clinical examination and survey of questionnaires was conducted with the HSS (Hospital for Special Surgery), LG (Lysholm-Gilquist), and KOOS (Knee Injury and Osteoarthritis Outcome Score) scores. Several radiological parameters were assessed on long-standing x-rays: mechanical tibio-femoral angle (mTFA), mLDFA, mechanical medial proximal tibia angle (mMPTA), joint-line convergence angle (JLCA). The t test was used for normally distributed data. The Mann-Whitney U test was performed in non-normally distributed data.

RESULTS

The mLDFA was 84.9° (SD±2.3) preop and changed to 91.9° (SD±3, 22.9) postop. The mTFA (mechanical tibio-femoral angle) was 5.2° (SD±2.9°) preop and - 1.8° (SD±2.9) postop demonstrating a difference of 6.7°. For analysis, the data was divided into two groups based on postop mLDFA. Group 1: mLDFA ≤ 90°; Group 2: > 90°. Postoperatively, a mean mLDFA of 88.6° (SD±1.4°) was measured in group 1 and 93.9° (SD±2.1) in group 2. The change in mLDFA was 4.7° (SD±1.6) in group 1 and 8.4° (SD±2.8) in group 2. Preoperatively, the mTFA was 4.8° (SD±1.9) in group 1 and 5.5° (SD±3.3) in group 2. Postoperatively, the mTFA decreased in group 1 by 4.8° (SD±2.3) to - 0.1° (SD±2.1). In group 2, the mTFA decreased by 8.2° (SD±3.8) to - 2.8° (SD±2.9). Regarding the HSS, group 1 showed a 10.4 points better score than group 2 (p<0.01). Also, regarding the Lysholm, a significant difference of 16.9 points was found (p<0.01).

CONCLUSION

Correction of valgus knees using closed wedge DFO leads to good clinical results. A postoperative mLDFA of 85-90° results in superior clinical outcome compared to mLDFA > 90°. Joint-line obliquity should be avoided using double level osteotomy, if needed.

LEVEL OF EVIDENCE

III.

Varus morphology and its surgical implication in osteoarthritic knee and total knee arthroplasty

BACKGROUND

Knee varus alignment represents a notorious cause of knee osteoarthritis. It can be caused by tibial deformity, combined tibial-femoral deformity and/or ligament imbalance. Understanding malalignment is crucial in total knee arthroplasty to restore frontal plane neutral mechanical axis. The aim of this study was to determine which factor contributes the most to varus osteoarthritic knee and its related surgical implications in performing a total knee arthroplasty.

METHODS

We retrospectively evaluated 140 patients operated for total knee arthroplasty due to a varus knee. Full-leg hip to ankle preoperative X-rays were taken. Radiological parameters recorded were: mechanical axis deviation, hip-knee-ankle, anatomical-mechanical angle, medial neck shaft angle, mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), lateral proximal femoral angle, lateral distal tibial angle (LDTA), femoral bowing, and length of tibia and femur. We also determined ideals tibial and femoral cuts in mm according to mechanical alignment technique. A R2 was calculated based on the linear regression between the predicted values and the observed data.

RESULTS

The greatest contributor to arthritic varus (R = 0.444) was MPTA. Minor contributors were mLDFA (R = 0.076), JLCA (R = 0.1554), LDTA (R = 0.065), and femoral bowing (R = 0.049). We recorded an average of 7.6 mm in lateral tibial cut thickness to restore neutral alignment.

CONCLUSIONS

The radiological major contributor to osteoarthritic varus knee alignment is related to proximal tibia deformity. As a surgical consequence, during performing total knee arthroplasty, the majority of the correction should therefore be made on tibial cut.

Influence of medial open wedge high tibial osteotomy on tibial tuberosity-trochlear groove distance

PURPOSE

Medial open wedge high tibial osteotomy (MOWHTO) is an effective treatment option for realignment of a varus knee. However, a simple supra-tuberositary osteotomy can lead to patella baja and potentially increases the tibial tuberosity-trochlear groove distance (TTTG). The purpose of this study was to quantify the influence of MOWHTO on TTTG.

METHODS

Three-dimensional (3D) surface models of five lower extremities with a varus hip-knee-ankle angle (HKA) and a borderline TTTG (≥ 15 mm), five lower extremities with a varus HKA and a normal TTTG (< 15 mm) and a 3D statistical shape model (SSM) of a neutrally aligned healthy knee were analysed by simulating MOWHTO with a stepwise increment of one degree of valgisation from the preoperative coronal deformity (0°-15°) for each patient, resulting in a total of 165 simulations. Postoperative 3D TTTG and tibial torsion (TT) were measured for each simulation. A mathematical formula was developed to calculate the increase of TTTG after MOWHTO. Mean differences between simulated and calculated TTTG were analysed.

RESULTS

Mean preoperative HKA was 6.5 ± 3.0° varus (range 0.8°-11.5°). Mean TTTG increased from 14.2 ± 3.2 mm (range 9.6-19.1) preoperatively to 18.8 ± 3.8 mm (range 14.5-25.0) postoperatively (p = 0.001). TTTG increased approximately linear by + 0.5 ± 0.2° (range 0.3-0.8) per 1° of valgisation with a high positive correlation (0.99, p = 0.001) from 0° to 15°. Mean difference between simulated and calculated TTTG was 0.03 ± 0.02 mm (range 0.01-0.07) per 1° of valgisation (p < 0.001).

CONCLUSION

MOWHTO results in an approximately linear increase in TTTG of + 0.5 mm per 1° of valgisation in the range from 0° to 15° and the lateralisation of the tibial tuberosity can be calculated reliably using the described formula. Preoperative analysis of TTTG in patients undergoing MOWHTO may prevent unintentional patellofemoral malalignment.

LEVEL OF EVIDENCE

III.

Medial closing-wedge distal femoral varus osteotomy: Symptoms and functional impact in cases of associated patellofemoral osteoarthritis. A two-year follow-up prospective pilot study

PURPOSE

To date, indications for distal femoral varus osteotomy (FVO) in cases of associated patellofemoral osteoarthritis (PFO) have yet to be clarified. The purpose of this prospective study is to assess the short-term symptoms, functional and radiological impact of a medial closing-wedge femoral varus osteotomy on the patellofemoral joint in patients with valgus deformities who are afflicted with lateral tibiofemoral osteoarthritis (LTFO) associated with PFO.

METHODS

Fourteen patients (15 knees) received a medial closing-wedge femoral varus osteotomy. The functional impact of an FVO on the patellofemoral joint was assessed based on the KOOS-PF (Knee Injury and Osteoarthritis Outcome Score-Patellofemoral Subscale), the Kujala score and the patellofemoral symptoms. Realignment of the patella was measured by the Merchant's patellofemoral congruence angle. The pre- and post-operative symptoms and functional scores were compiled prospectively and compared two years after the surgery.

RESULTS

The Kujala patellofemoral functional scores and the KOOS-PF showed considerable improvement with a differential of +37.5 points ± 20.4 and +42.7 points ± 19.3 (p < .01) respectively. The average Merchant's congruence angle went from 8.8° laterally to 3.6° medially, resulting in medialization of the patella, with a significant difference (p < .01). Based on the specific clinical analysis of the patellar joint, preoperative J-sign was identified in 26.7% of patients (n = 4) and was not found during postoperative examination (p = .1). Preoperative apprehension test was identified in 33.3% of patients (n = 5) against 13.3% (n = 2) after surgery (p = .39). Preoperative pain extension test was identified in 40% of patients (n = 6) against 20% during postoperative clinical analysis (p = .43).

DISCUSSION

Although the threshold of significance for patellofemoral symptoms was not reached, the medial closing-wedge femoral varus osteotomy induces a significant medialization of the patella (Merchant's congruence angle) and improves short-term functional results even with co-existing patellofemoral osteoarthritis. Due to the lack of specificity of the patellofemoral scores, patellofemoral osteoarthritis improvement is difficult to determine on its own, but does not represent a contraindication to FVO.

LEVEL OF EVIDENCE

III. Prospective clinical study.

Development of the double level osteotomy in severe varus osteoarthritis showed good outcome by preventing oblique joint line

INTRODUCTION

The purpose of the study was to describe the development of the surgical technique of double level osteotomy in patients with severe varus malalignment and to investigate the clinical and radiological outcome. It was hypothesized that good clinical results without a higher complication rate can be achieved by double level osteotomy to normalize joint angles and avoid joint line obliquity even in cases of progressed osteoarthritis.

MATERIALS AND METHODS

Between 2011 and 2014, 33 patients (37 knees) undergoing double level osteotomies (open wedge HTO and closed wedge DFO) were included; of these, 24 patients (28 knees) were available in mean of 18 ± 10 months for the follow-up examination. Indication was symptomatic varus malalignment and medial compartment osteoarthritis. Postoperatively, these patients were assigned to 20 kg partial weight-bearing using two crutches for 6 weeks followed by full weight-bearing. No braces or casts were used. Full weight-bearing long leg anteroposterior radiographs were obtained preoperatively, after 6 weeks and at the time of final follow-up. Mechanical tibiofemoral angle (mTFA), mechanical lateral distal femoral angle (mLDFA) and medial proximal tibia angle (MPTA) were measured. Clinical outcome was evaluated using Lequesne-, Lysholm-, Oxford-, and IKDC-score at the time of follow-up.

RESULTS

The preoperative mTFA of - 11 ± 3° increased to 0 ± 2° at final follow-up. The difference between mTFA-planning and final follow-up was - 2 ± 3° (p < 0.0006). At final follow-up, MPTA and mLDFA were 89.2 ± 2° and 87 ± 2°, respectively. The Lysholm, Oxford, Lequesne, and IKDC scores were 88 ± 13, 44 ± 3, 2 ± 2, and 77 ± 12, respectively.

CONCLUSIONS

This study showed that double level osteotomy for the patients with severe varus malalignment and medial compartment osteoarthritis normalises the alignment, joint-angles, avoids joint line obliquity, and leads to good clinical results, despite progressive osteoarthritis.

LEVEL OF EVIDENCE

Case series, Level IV.

[Flexion and extension osteotomy of the knee]

OBJECTIVES

Flexion and extension osteotomy of the knee for symptomatic malalignment in the sagittal plane.

INDICATIONS

Congenital/posttraumatic bony deficiencies in flexion/pathologic hyperextension in the knee. Additional treatment for ligament reconstruction.

CONTRAINDICATIONS

Absolute: Infection, critical soft tissue situation, circulatory disorders. Relative: Osteoporosis, heavy smoker, obesity, reduced patient compliance.

SURGICAL TECHNIQUE

Diagnostic arthroscopy of the knee. If the malposition is located at the proximal tibia, an extending or flexing high tibial osteotomy with correction of the tibial slope is carried out. If the malalignment is referred to the distal femur, the adjustment is performed by a distal femoral osteotomy.

POSTOPERATIVE MANAGEMENT

Partial weight bearing with 20 kg for the first 6 postoperative weeks. Due to the tuberositas tibiae osteotomy, it is necessary to restrict the movement of the knee for the first 6 weeks.

RESULTS

Between 2015 and 2016, 11 patients (2 female, 9 male) were treated with a flexion or extension osteotomy of the knee. Of these patients, 2 had symptomatic hyperflexion, 7 had restriction of movement with an exaggerated tibial slope, and 2 patients had an extension deficiency according to a malalignment of the distal femur. After surgery, the symptomatic pathologic movement of the knee was improved in every patient. One patient had pseudarthrosis during the healing process, which required a second operation with reosteosynthesis and bony grafting. These results are also reflected in an improvement of the preoperative IKDC score from 52.7 (range 37-82) to 1 year postoperative 75.8 (range 67-84). The Lysholm score increased from preoperative 40.2 (range 15-73) to postoperative 84.3 (range 68-91).

Distal femoral valgus osteotomy: bone healing time in single plane and biplanar technique

Varus deformity can be localized in the tibia, in the femur or in both. If varus deformity is localized within the femur, it is mandatory to correct it in the femur. This report presents the technique and results of a consecutive case series of lateral uniplanar and biplanar closed-wedge valgus osteotomy of the distal femur for the treatment of varus deformity of the knee. Retrospectively, fifteen patients (sixteen knees) were identified. Indications for surgery varied from unloading an osteoarthritic medial compartment to reduction to symmetrical varus leg alignment. Pre- and post-operative X-rays, including a full leg radiograph, were assessed as well as bone healing time at follow-up intervals. Clinical outcome was assessed using different questionnaires. There were nine male and six female patients with a median age at surgery of 45 (±14) years. The mLDFA changed from 95.9° (±2.7°) preoperatively to 89.3° (±2.9°) post-operatively. Preoperative planning and the use of angle stable implants resulted in accurate corrections according to preoperative aims in all but one patient. At follow-up (mean, 40 months), the mean VAS score was 2.5 (±2.4) and the WOMAC score averaged 80 (±20). The mean bone healing time of biplanar osteotomies (4 ± 3 months) was shorter than in the uniplanar osteotomies (6 ± 3 months). Distal lateral closed-wedge valgus osteotomy of the femur for the treatment of femoral varus deformities resulted in clinical improvement and accurate corrections in patients with different aims for correction. A biplanar osteotomy technique shortens bone healing time.