Influence of lateral hinge fractures on biplanar medial closing-wedge distal femoral osteotomy for valgus knee: a new classification of lateral hinge fracture.

BACKGROUND: The purpose of this study was to examine the influence of lateral hinge fractures in medial closing-wedge distal femoral osteotomy (MCWDFO) on bone union. METHODS: Twenty-one patients were followed-up for more than 1 year after MCWDFO. The incidence and type of hinge fracture, as well as the course of bone healing, were investigated. Slow healing was defined as bone union was not obtained until 3 months after surgery. RESULTS: Hinge fractures were observed in 12 cases (57%). There were three types of hinge fractures. Type 1: the lateral cortex was completely cut through (4 cases), type 2: the osteotomy line was too proximal (6 cases), and type 3: the hinge point was significantly medial (2 cases). There was a significant difference in the mean correction angles between hinge fracture and no-fracture cases, with the mean angles being 13.8 ± 4.0° and 9.6 ± 3.1°, respectively. Sixty-seven percent (8/12) of cases with hinge fractures developed slow healing. Among the hinge fracture cases, when there was no displacement of the hinge fracture and good contact with the anterior flange, 40% (2/5) of cases developed slow healing. If there was displacement of the hinge or no contact of the anterior flange, 86% (6/7) of cases developed slow healing. In contrast, only 11% (1/9) of subjects who did not have a hinge fracture, developed slow healing. In 67% (6/9) of cases with slow healing, a correction loss of 2° or greater (average: 4.3 degrees valgus) was observed. There were no cases of non-union. Clinical outcomes at 1 year showed no significant difference between the groups with and without hinge fractures. CONCLUSIONS: There is a very high risk of hinge fracture in patients undergoing MCWDFO. Hinge fractures often lead to slow healing and a loss of correction. We recommend the endpoint of the distal lateral cortex of the femur as the ideal hinge point for the prevention of hinge fractures. Bone union is obtained slowly in even all hinge fracture cases without revision surgery. Consequently, surgical results are not affected by the occurrence of hinge fracture at 1 year.

Closing-wedge distal femoral osteotomy combined with medial patellofemoral ligament reconstruction for recurrent patellar dislocation with genu valgum.

BACKGROUND: Medial patellofemoral ligament reconstruction (MPFLR) is a well-established procedure for addressing recurrent patellar dislocation (RPD) in young patients. However, despite being a promising procedure for RPD with genu valgum, there is a scarcity of reports on simultaneous MPFLR and closing-wedge distal femoral osteotomy (CWDFO). The purpose of the present study was to observe and analyse the clinical and imaging findings of CWDFO combined with MPFLR for RPD with genu valgum. METHODS: From May 2015 to April 2018, 25 patients with RPD and genu valgum were surgically treated in our department. Anteroposterior long-leg, weight-bearing, lower-extremity radiographs, lateral radiographs and computed tomography (CT) scans of the patellofemoral joint were obtained, and the anatomical femorotibial angle (aFTA), mechanical lateral distal femoral angle (mLDFA), weight-bearing line rate (WBLR), patellar height, patellar lateral shift (PLS) and tibial tubercle-trochlear groove (TT-TG) distance were analysed. Validated knee scores, such as the Kujala, Lysholm, visual analogue scale (VAS) scores and Tegner socres, were evaluated preoperatively and 2 years postoperatively. RESULTS: 25 patients, with an average age of 19.8 years (14-27), were evaluated. During the 2-year follow-up period, all patients were able to achieve a better sports level without any problems, with no recurrence of patellar instability. Compared with preoperation, the aFTA, mLDFA, WBLR and PLS showed statistically significant improvement following the procedure (p < 0.001). Meanwhile, no significant differences in the Insall index and TT-TG distance were found. The mean Kujala score, average Lysholm score, VAS score and Tegner socres showed significant postoperative improvement. CONCLUSIONS: CWDFO combined with MPFLR is a suitable treatment for RPD with genu valgum, and can lead to significant improvement in the clinical and imaging findings of the knee in the short term.

[Application of a new type of angle-adjustable osteotomy guide in closing wedge distal femoral osteotomy].

Objective: To explore the feasibility of fast and accurate osteotomy using a new angle adjustable osteotomy guide (AAOG) in closing wedge distal femoral osteotomy(CWDFO). Methods: The clinical data of 14 patients (17 knees) with valgus knee treated with CWDFO at Department of Integrated Chinese and Western Medicine Orthopedics, Honghui Hospital, Xi'an Jiaotong University from January 2018 to July 2019 were analyzed retrospectively. There were 3 males and 11 females, aging (41.4±16.4) years (range: 18 to 56 years). The body mass index was (23.5±3.5) kg/m(2) (range: 18.1 to 28.9 kg/m(2)). The guide pins were placed with the assistance of the self-designed AAOG. Before the surgery, Solidworks software was used to calculate the correction angle and the osteotomy radius accurately. The osteotomy guide was adjusted according to these two parameters. During the surgery, the adjusted osteotomy guide was placed to the surface of bone closely and the guide pins were drilled into the bone through the guide holes. The position of the guide pins was confirmed under fluoroscopy. The osteotomy was finished under guide of pins and fixed with Tomofix plate (Synthes). The times and duration of placement of the guide pins, the times of X-ray examination, the planned and actual thickness of the osteotomy wedge, the top and bottom area of the osteotomy wedge, the posterior distal femoral angle(PDFA), the correction of the weight line, and the American Knee Society Score(AKSS) and Tegner scores were collected and compared by paired t test or Kruskal-Wallis non-parametric test. Healing time after osteotomy and complications were recorded. Results: The guide pins were successfully placed once in 10 knees, adjusted once in 5 knees and twice in 2 knees. The time spent in placing all the 6 pins was 82.4 seconds (range: 51 to 125 seconds), and the times of X-ray examination was 1.5 times (range: 1 to 5 times). The top and bottom areas of the osteotomy wedge were (5.52±0.52)cm(2) and (5.36±0.49)cm(2). PDFA was (85.2±2.6)° preoperatively and (85.5±1.4)° postoperatively (t=-0.401, P>0.05). The thickness of the osteotomy was (11.3±1.9)mm according to the preoperative plan, and the actual thickness was (8.1±1.7)mm. All the patients were followed up for 6 months after surgery and AKSS and Tegner scores improved significantly (all P<0.05). The correction of the weight lines was within the ideal range. Fractures of the hinge point occurred in 3 knees. All of the osseous healing without complications. Conclusion: The new osteotomy guide helps to place the guide pins rapidly and precisely according to the preoperative planning, which should be widely used in clinical applications with promising outcomes.

Three dimensional patient-specific printed cutting guides for closing-wedge distal femoral osteotomy.

PURPOSE: Medial closing-wedge distal femoral osteotomy (MCWDFO) was used to treat valgus knee malalignment combined with lateral compartment disease. The clinical outcome of the osteotomy depends on the accurate correction of valgus malalignment. The aim of this study was to evaluate the accuracy of a MCWDFO assisted by three-dimensional (3D)-printed cutting guides and locking guides. PATIENTS AND METHODS: Thirty-three consecutive patients (33 knees) were operated on using the same MCWDFO. 3D-printed cutting guides and locking guides were used to locate the osteotomy cut plane and to facilitate closing the wedge in 12 patients (3D-guide group). Another 21 patients (conventional group) underwent MCWDFO following the conventional technique. The desired correction was defined as a weight-bearing line (WBL) coordinate 50% of the width of the tibial plateau from the medial tibial margin. The deviation between the planned and executed WBL coordinate, surgical time and fluoroscopic time were compared. RESULTS: The mean deviation between the planned and executed WBL coordinate was 4.9% in the 3D-guide group and 7.6% in the conventional group (P = 0.024). Shorter surgical time was found in the 3D-guide group (mean, 77.7 minutes vs. mean, 96.5 minutes; P < 0.001), while the mean number of intra-operative fluoroscopic images was 6.1, compared with 34.7 in the conventional group (P < 0.001). CONCLUSION: The use of 3D-printed cutting guides and locking guides can increase the precision of the MCWDFO in patients with lateral compartment disease and valgus deformity, making our surgery more efficiency and occupying less fluoroscopic time.

Soft Tissue Stabilization of the Hinge Position for Lateral Closing-Wedge Distal Femoral Osteotomy: An Anatomic Study.

Background: Soft tissue plays an important role in stabilizing the hinge point for osteotomy around the knee. However, insufficient data are available on the anatomic features of the soft tissue around the hinge position for lateral closing-wedge distal femoral osteotomy (LCWDFO). Purpose: To (1) anatomically analyze the soft tissue around the hinge position for LCWDFO, (2) histologically analyze the soft tissue based on the anatomic analysis results, and (3) radiologically define the appropriate hinge point to prevent unstable hinge fracture based on the results of the anatomic and histological analyses. Study Design: Descriptive laboratory study. Methods: In 20 cadaveric knees (age, 82.7 ± 7.8 years; range, 60-96 years), the soft tissue of the distal medial side of the femur was anatomically analyzed. The thicknesses of the periosteum and direct insertion of the adductor tendon (AT) were histologically examined and measured using an electron microscope. The thickness of the periosteum was visualized graphically, and the graph of the periosteum and radiograph of the knee were overlaid using image editing software. The appropriate hinge position was determined based on the periosteal thickness and attachment of the AT. Results: The mean thickness of the periosteum of the metaphysis was 352.7 ± 58.6 µm (range, 213.6-503.4 µm). The overlaid graph and radiograph revealed that the thickness of the periosteum changed at the part corresponding to the transition between the diaphyseal and metaphyseal ends of the femur. The mean width of the AT attached to the distal medial femur from the adductor tubercle toward the distal direction was 7.9 ± 1.3 mm (range, 6.3-9.7 mm). Conclusion: Results indicated that the periosteum and AT support the hinge for LCWDFO within the area surrounded by the apex of the adductor tubercle and the upper border of the posterior part of the lateral femoral condyle. Clinical Relevance: When the hinge point is located within the area surrounded by the apex of the adductor tubercle and the upper border of the posterior part of the lateral femoral condyle, these soft tissues work as stabilizers, and there is no risk of cutting into the joint space.

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.

Change in quality of life and return to work and sports after isolated closing-wedge distal femoral osteotomy.

PURPOSE: To analyze return to work and sports, and health-related quality of life (HRQoL) after closing-wedge distal femoral osteotomy (CWDFO) for valgus deformity and lateral compartmental osteoarthritis. METHODS: Thirty-three patients underwent isolated CWDFO in our center between January 2018 and June 2020 were enrolled, of whom 32 and 23 patients were included in the return-to-work and return-to-sports analyses, respectively. Short Form-36 (SF-36), Tegner score, Knee injury and Osteoarthritis Outcome Score (KOOS) and visual analog scale (VAS) pain score were compared preoperatively and postoperatively. And postoperative complications were recorded. RESULTS: Overall, 33 patients were contacted at a mean follow-up of 37.94 ± 6.68 months, with a median age of 35 years (range: 26-63 years) at the surgery time. The physical component summary of SF-36 (p < 0.001) increased significantly at 1 year postoperatively. All patients returned to work, including 96.86% who returned to the same level of work in 1.89 ± 0.98 months, and to sports, including 78.26% who returned to the same sport level in 6.50 ± 2.05 months. Rates of returning to work (p = 0.215) and sports (p = 0.165) did not differ with work/sports intensity. Tegner scores (p = 0.025) and VAS pain scores (p < 0.001) decreased, and KOOS (p < 0.001) increased at 1 year postoperatively. Revision/conversion surgery was not required. In all, 30.43% patients reported a subjective decrease in sports ability; 82.61% patients considered their sports ability acceptable. CONCLUSION: Patients returned to work/sports after isolated CWDFO, and had increased HRQoL. Patients playing high-impact sports had lower rates of returning to the same sport level, and may require preoperative counseling. LEVEL OF EVIDENCE: IV, Case series.

Effect of Medial Closing Wedge Distal Femoral Varization Osteotomy on Coronal Ankle and Hindfoot Alignment.

BACKGROUND: To date, only a few studies have reported postoperative changes in coronal ankle alignment after valgus knee correction through medial closing wedge distal femoral varization osteotomy (MCWDFO). This study aimed to measure the changes of MCWDFO on coronal ankle and hindfoot alignment. METHODS: We retrospectively reviewed the radiographic findings of 27 consecutive patients (34 cases) with knee valgus malalignment who underwent MCWDFO for either lateral knee joint osteoarthritis (OA) or recurrent patellar subluxation/dislocation (RPD). Several radiographic parameters were measured and compared based on the reason for operation, followed by the status of preoperative hindfoot alignment (hindfoot alignment angle [HAA] > 4 degrees, varus; -4 degrees ≤HAA ≤ 4 degrees, neutral; HAA < -4 degrees, valgus) in each group. RESULTS: Overall, pre- and postoperative hindfoot alignments were within the neutral alignment range and were not significantly changed after the operation (P > .05). Nineteen cases were for lateral knee OA and 15 were for RPD, respectively. In both groups, preoperative neutral hindfoot alignments accounted for the largest portion (52.6% in the lateral OA group; 80.0% in the RPD group). Postoperatively, regardless of the reason for operation, hindfoot alignments changed toward the neutral range in all subgroups (ie, no changes in the preoperative neutral group; increased in the valgus group; decreased in the varus group). CONCLUSION: We recommend that surgeons leave the hindfoot untouched when they plan the MCWDFO to correct knee joint valgus malalignment concomitant with hindfoot valgus or varus deviation as the hindfoot malalignment appears to change toward the neutral range postoperatively. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Predictive Factors for Lateral Hinge Fracture in Medial Closing Wedge Distal Femoral Osteotomy.

BACKGROUND: Recent studies have reported that lateral hinge fracture (LHF) has a negative effect on bone healing at the osteotomy site after medial closing wedge distal femoral osteotomy (MCDFO). However, limited evidence exists in the literature regarding the predictive factors for LHF in MCDFO. HYPOTHESIS: A large medial closing gap and a lateral hinge position in the supracondylar area would increase plain radiography-based and/or computed tomography (CT)-based LHF in MCDFO. STUDY DESIGN: Case control study; Level of evidence, 3. METHODS: We retrospectively evaluated 67 knees of 53 patients (mean age, 37.4 ± 16.9 years) who underwent MCDFO between May 2009 and June 2021. The surgical indications for MCDFO were genu valgum deformity combined with either lateral compartment osteoarthritis or recurrent patellar dislocation. The presence of LHF was evaluated based on immediate postoperative plain radiography and CT scans. The predictive factors for LHF in MCDFO were investigated using multivariate logistic regression analysis. RESULTS: LHFs were identified in 21 knees (31.3%) through plain radiography and in 40 knees (59.7%) through CT. Multivariate logistic regression analysis showed that the medial closing gap and lateral hinge position were predictive factors for plain radiography- and CT-based LHF after MCDFO. Controlling for other variables, we found that an increase in the medial opening gap by 1 mm increased the likelihood of plain radiography-based LHF by a factor of 1.805 (95% CI, 1.291-2.525; P = .001) and CT-based LHF by 1.333 (95% CI, 1.003-1.772; P = .048). Moreover, a lateral hinge position in the supracondylar area increased the likelihood of plain radiography-based LHF by a factor of 9.870 (95% CI, 2.179-44.720; P = .003) and CT-based LHF by 5.686 (95% CI, 1.124-28.754; P = .036). CONCLUSION: A large medial closing gap and lateral hinge position in the supracondylar area are associated with LHF in MCDFO. Care should be taken to prevent LHF in MCDFO with a large medial closing gap. Moreover, a lateral hinge position in the supracondylar area should be avoided to decrease the incidence of LHF in MCDFO.

Detection of Lateral Hinge Fractures After Medial Closing Wedge Distal Femoral Osteotomy: Computed Tomography Versus Plain Radiography.

BACKGROUND: Limited evidence exists in the literature regarding the detection rates of lateral hinge fracture (LHF) on computed tomography (CT) after medial closing wedge distal femoral osteotomy (MCDFO). Moreover, the effect of LHF on bone healing after MCDFO remains unclear. HYPOTHESIS: The detection rates of LHF after MCDFO would be higher on CT than on plain radiography. The incidence of problematic bone healing would be higher in the knees with LHF than in those without LHF. STUDY DESIGN: Cohort study (diagnosis), Level of evidence, 3. METHODS: Patients who underwent MCDFO between May 2009 and July 2019 were retrospectively evaluated. The presence of LHF was evaluated using immediate postoperative plain radiography and CT. The detection rates of LHF on plain radiography and CT were compared. The incidence of problematic bone healing (nonunion, delayed union, and loss of correction) was also compared between the knees with LHF and those without LHF. RESULTS: A total of 55 knees of 43 patients (mean age, 37.7 ± 16.7 years) were included in the study. Although 33 LHFs were detected on CT, only 19 LHFs were detected on plain radiography. The detection rate of LHF was significantly higher on CT than on plain radiography (60% vs 34.5%; P = .008). At 1-year follow-up, 10 cases of problematic bone healing (1 nonunion, 4 delayed unions, and 5 losses of correction) were identified. The incidence of problematic bone healing was significantly higher in the knees with LHF than in those without LHF as shown on plain radiography (36.8% vs 8.3%; P = .001) and CT (30.3% vs 0%; P = .004). CONCLUSION: LHF can be detected better on CT than on plain radiography and has a negative effect on bone healing after MCDFO. For patients with LHF detected on either plain radiography or CT, careful rehabilitation with close follow-up is recommended.

The Ideal Location of the Lateral Hinge in Medial Closing Wedge Osteotomy of the Distal Femur: Analysis of Soft Tissue Coverage and Bone Density.

BACKGROUND: Although an appropriate hinge position to prevent unstable lateral hinge fractures is well established in medial opening wedge high tibial osteotomy, the position during medial closing wedge distal femoral osteotomy has not been elucidated. PURPOSE/HYPOTHESIS: The purpose was to evaluate the ideal hinge position that would prevent an unstable lateral hinge fracture during biplanar medial closing wedge distal femoral osteotomy based on soft tissue coverage and bone density around the hinge area. The hypothesis was that the ideal hinge position could be clarified by analyzing soft tissue coverage and bone density around the lateral hinge area. STUDY DESIGN: Controlled laboratory study. METHODS: In 20 cadaveric knees (mean age, 70.3 ± 19.2 years), the femoral attachment of the gastrocnemius lateral head was quantitatively analyzed as a soft tissue stabilizer using digital photography and fluoroscopy. Then, medial closing wedge distal femoral osteotomy was performed, locating the lateral hinge either inside (group 1) or outside (group 2) the femoral attachment of the gastrocnemius lateral head, and the incidence of unstable lateral hinge fractures was compared between the 2 groups. Cortical bone density around the lateral hinge was measured using Hounsfield units on 30 computed tomography scans and reconstructed as a 3-dimensional mapping model. The transitional zone with low bone density was regarded as the safe hinge position with an increased capacity for bone deformation. RESULTS: The upper and lower margins of the femoral attachment of the gastrocnemius lateral head were 9.1 ± 0.9 mm above and 8.0 ± 1.4 mm below the upper border of the lateral femoral condyle, respectively, and the femoral attachment of the gastrocnemius lateral head was widest in the anteroposterior dimension 0.4 ± 1.7 mm above the upper border of the lateral femoral condyle. The incidence of unstable lateral hinge fractures during osteotomy was significantly decreased in group 1 compared with group 2 (group 1: 0/10; group 2: 5/10; P = .01). An isolated transitional zone with low bone density was observed in all 30 knees and located 1.3 ± 0.8 mm above the upper border of the lateral femoral condyle. Bone density of the transitional zone with low bone density was significantly lower than surrounding femoral cortices (P < .001). CONCLUSION: Only the upper border of the lateral femoral condyle can be recommended as an ideal hinge position to prevent unstable lateral hinge fractures during biplanar medial closing wedge distal femoral osteotomy based on soft tissue coverage and bone density. CLINICAL RELEVANCE: When the hinge is positioned at the upper border of the lateral femoral condyle during biplanar medial closing wedge distal femoral osteotomy, the risk of unstable hinge fractures can be minimized.