3D Killer Turn Angle in Transtibial Posterior Cruciate Ligament Reconstruction Is Determined by the Graft Turning Angle both in the Sagittal and Coronal Planes

ObjectiveDuring the transtibial posterior cruciate ligament (PCL) reconstruction, surgeons commonly pay more attention to the graft turning angle in the sagittal plane (GASP), but the graft turning angle in the coronal plane (GACP) is always neglected. This study hypothesized that the three‐dimensional (3D) killer turn angle was determined by both the GASP and GACP, and aimed to quantitively analyze the effects of the GASP and GACP on the 3D killer turn angle.MethodsThis was an in‐vitro computer simulation study of transtibial PCL reconstruction using 3D knee models. Patients with knee injuries who were CT scanned were selected from the CT database (April 2019 to January 2021) at a local hospital for reviewing. A total of 60 3D knees were simulated based on the knees'' CT data. The femoral and tibial PCL attachment were located on the 3D knee model using the Rhinoceros software. The tibial tunnels were simulated based on different GASP and GACP. The effects of the GASP and GACP on the 3D killer turn angle were quantitatively analyzed. One‐way analysis of variance was used to compare the outcomes in different groups. The regression analysis was performed to identify variables of the GASP and GACP which significantly affected 3D killer turn angle.ResultsThe 3D killer turn angle showed a significant proportional relationship not only with the GASP (r ² > 0.868, P < 0.001), but also with the GACP (r ² > 0.467, P < 0.001). Every 10° change of the GACP caused 2.8° to 4.4° change of the 3D killer turn angle, whereas every 10° change of the GASP caused 6.4° to 9.2° change of the 3D killer turn angle.ConclusionsThe 3D killer turn angle was significantly affected by both the GASP and GACP. During the transtibial PCL reconstruction, the proximal anterolateral tibial tunnel approach could increase the 3D killer turn angle more obviously compared with the most distal anteromedial tibial tunnel approach. To minimize the killer turn effect, both the GASP and GACP were required to be considered to increase.     

Efficacy of Transosseous Tunnel Placement for Triple Endobutton Plate in Acromioclavicular Joint Reconstruction: A Three‐Dimensional Printing Guide Design Technology

ObjectiveExplore an accurate transosseous tunnel drilling method based on three‐dimensional (3D) printing technology for acromioclavicular joint reconstruction (ACD), design a guide design, and evaluate its accuracy.MethodsUsing Mimics software to reconstruct 100 cases of acromioclavicular joint computed tomography (CT) data. In design 2, the non‐collinear tunnel is superimposed on the 3D model, and a virtual drilling is performed between the clavicle and the coracoid using a triple inner gusset. Then, in the Geomagic Studio software model, an elliptical plane is calculated and extracted as a guide design for precise drilling. Then put the design and the 3D shoulder model together for 3D printing. Ten lengths were measured, and the effects of the virtual model, the actual model, and the guide rail design were compared.ResultsWe successfully compared 10 parameters of 3D virtual model and actual model. There was no significant difference between actual and virtual bone tunnels in 10 measurements (P > 0.05).ConclusionsThe accuracy of ACD combined with 3D printing guidance design technology in the transosseous tunnel of adult shoulder is reliable.     

Evaluation of Femoral Tunnel Positioning Using 3-Dimensional Computed Tomography and Radiographs after Single Bundle Anterior Cruciate Ligament Reconstruction with Modified Transtibial Technique

Background

The purpose of this study is to report a modified transtibial technique to approach the center of anatomical femoral footprint in anterior cruciate ligament (ACL) reconstruction and to investigate the accurate femoral tunnel position with 3-dimensional computed tomography (3D-CT) and radiography after reconstruction.

Methods

From December 2010 to October 2011, we evaluated 98 patients who underwent primary ACL reconstruction using a modified transtibial technique to approach the center of anatomical femoral footprint in single bundle ACL reconstruction with hamstring autograft. Their femoral tunnel positions were investigated with 3D-CT and radiography postoperatively. Femoral tunnel angle was measured on the postoperative anteroposterior (AP) radiograph and the center of the femoral tunnel aperture on the lateral femoral condyle was assessed with 3D-CT according to the quadrant method by two orthopedic surgeons.

Results

According to the quadrant method with 3D-CT, the femoral tunnel was measured at a mean of 32.94% ± 5.16% from the proximal condylar surface (parallel to the Blumensaat line) and 41.89% ± 5.58% from the notch roof (perpendicular to the Blumensaat line) with good interobserver (intraclass correlation coefficients [ICC], 0.766 and 0.793, respectively) and intraobserver reliability (ICC, 0.875 and 0.893, respectively). According to the radiographic measurement on the AP view, the femoral tunnel angles averaged 50.43° ± 7.04° (ICC, 0.783 and 0.911, respectively).

Conclusions

Our modified transtibial technique is anticipated to provide more anatomical placement of the femoral tunnel during ACL reconstruction than the former traditional transtibial techniques.     

Laser-Guided Placement of the Tibial Guide in the Transtibial Technique for Anterior Cruciate Ligament Reconstruction

In anterior cruciate ligament (ACL) reconstruction, it is important to determine the location and direction of the femoral bone tunnel when using the transtibial technique. Accurately identifying the anatomic location at which to make the femoral bone tunnel for double-bundle ACL reconstruction is not a straightforward procedure. We describe a new method in which the centrum of the femoral tunnel is marked with an awl and a laser beam–guided technique is used to place the tibial pin. This procedure allows us to mark the desired location of the femoral tunnel before drilling the tibial bone tunnel when using the transtibial technique. This is the first report of a laser-guided technique used in arthroscopic surgery. We used a laser beam to determine the location of the femoral tunnel—the anatomic site needed to perform the intra-articular drilling in the tibia. In this technique, a laser pointer is set at the tibial guide, which reflects the laser beam and illuminates the point where the femoral bone tunnel should be made. Our method offers an easy and accurate way to reconfirm the tibial placement before drilling.     

A Reproducible Landmark for the Tibial Tunnel Origin in Anterior Cruciate Ligament Reconstruction: Avoiding a Vertical Graft in the Coronal Plane

Improper tunnel placement during anterior cruciate ligament reconstruction may result in residual instability. Proper femoral tunnel orientation relies on tibial tunnel placement with a transtibial technique. Our recommended technique is to use the junction of the anterior border of the superficial medial collateral ligament and the superior border of the gracilis tendon as a reproducible anatomic landmark for the tibial tunnel. In a cadaveric model the mean angle for the tibial tunnel was 65.7° ± 5.5° in the coronal plane and 75° ± 7.2° in the sagittal plane. By use of the clock-face method, the mean angle for the femoral tunnel was 44.9° ± 13°, or approximately the 10:30 position (for a right knee) or 1:30 position (for a left knee).     

Three-Dimensional Reconstruction Computed Tomography Evaluation of Tunnel Location during Single-Bundle Anterior Cruciate Ligament Reconstruction: A Comparison of Transtibial and 2-Incision Tibial Tunnel-Independent Techniques

Background

Anatomic tunnel positioning is important in anterior cruciate ligament (ACL) reconstructive surgery. Recent studies have suggested the limitations of a traditional transtibial technique to place the ACL graft within the anatomic tunnel position of the ACL on the femur. The purpose of this study is to determine if the 2-incision tibial tunnel-independent technique can place femoral tunnel to native ACL center when compared with the transtibial technique, as the placement with the tibial tunnel-independent technique is unconstrained by tibial tunnel.

Methods

In sixty-nine patients, single-bundle ACL reconstruction with preservation of remnant bundle using hamstring tendon autograft was performed. Femoral tunnel locations were measured with quadrant methods on the medial to lateral view of the lateral femoral condyle. Tibial tunnel locations were measured in the anatomical coordinates axis on the top view of the proximal tibia. These measurements were compared with reference data on anatomical tunnel position.

Results

With the quadrant method, the femoral tunnel centers of the transtibial technique and tibial tunnel-independent technique were located. The mean (± standard deviation) was 36.49% ± 7.65% and 24.71% ± 4.90%, respectively, from the over-the-top, along the notch roof (parallel to the Blumensaat line); and at 7.71% ± 7.25% and 27.08% ± 7.05%, from the notch roof (perpendicular to the Blumensaat line). The tibial tunnel centers of the transtibial technique and tibial tunnel-independent technique were located at 39.83% ± 8.20% and 36.32% ± 8.10%, respectively, of the anterior to posterior tibial plateau depth; and at 49.13% ± 4.02% and 47.75% ± 4.04%, of the medial to lateral tibial plateau width. There was no statistical difference between the two techniques in tibial tunnel position. The tibial tunnel-independent technique used in this study placed femoral tunnel closer to the anatomical ACL anteromedial bundle center. In contrast, the transtibial technique placed the femoral tunnel more shallow and higher from the anatomical position, resulting in more vertical grafts.

Conclusions

After single-bundle ACL reconstruction, three-dimensional computed tomography showed that the tibial tunnel-independent technique allows for the placement of the graft closer to the anatomical femoral tunnel position when compared with the traditional transtibial technique.     

Three‐Dimensional Distribution of Bone‐Resorption Lesions in Osteonecrosis of the Femoral Head Based on the Three‐Pillar Classification

ObjectiveTo investigate three‐dimensional distribution of bone‐resorptive lesions based on the three‐pillar classification and its effect on the disease progression of osteonecrosis of the femoral head (ONFH).MethodsA total of 194 femoral head CT images from 117 patients diagnosed with ARCO stage II and III ONFH were retrospectively reviewed from April 2014 to February 2019. Three‐dimensional structures of the femoral head and the bone‐resorptive lesions were reconstructed. Using the three‐pillar classification and coronal plane of the femoral head, we divided each femoral head into six regions to observe the location characteristics of bone‐resorption lesions, and explore the destruction of different areas of the femoral head by the bone‐resorptive lesions. Then the hips were divided into two groups based on whether they contained bone‐resorption lesions and compared the difference of stage II and stage III between the two groups.ResultsThe regional distribution revealed 39 (27.27%), 55 (38.46%), six (4.20%), 23 (16.08%), 17 (11.89%) and three (2.10%) bone‐resorptive lesions in regions I, II, III, IV, V and VI respectively. The lateral pillar, AL (I + IV), contained 44.76% of the lesions, central pillar, C (II + V), 48.95%, and medial pillar, M (III + VI), 6.29%. Moreover, there were 81.82% bone‐resorption lesions in anterolateral pillar, AL (I + II + IV), and 18.18% in posteromedial pillar, PM (III + V + VI). In all ONFH hips, the lateral pillar of 81(88.04%) femoral heads were affected, the central pillar of 84 (91.30%) femoral heads were affected, and the medical pillar of 29 (31.52%) femoral heads were affected. The ratio of ARCO stage III in the group with bone‐resorption lesions was significantly higher than that of the group without bone‐resorption lesions (76.09% vs 30.39%, P < 0.001).ConclusionsThis study demonstrated that the bone‐resorption lesions are mainly distributed in the lateral and central pillar of the femoral head, and the two pillars of the femoral head are usually involved by bone‐resorption lesions. Furthermore, the ratio of ARCO stage III in the group with bone‐resorption lesions was significantly higher than that of the group without bone‐resorption lesions, suggesting that the bone‐resorption lesions might accelerate the progression of ONFH.     

Morphological Asymmetry of Pelvic Rings: A Study Based on Three‐Dimensional Deviation Analysis

ObjectiveTo evaluate the morphological asymmetry of pelvic rings existing in healthy individuals in terms of three‐dimensional (3D) geometric shapes.MethodsThis study was a retrospective self‐control study. CT images of healthy pelvises, scanned from Jan 2014 to Jan 2019, were taken from 159 subjects (88 males and 71 females) aged 20 to 59 years (39.1 ± 8.7 years). Digital pelvic ring models were reconstructed from CT images and then flipped over the corresponding sagittal planes to obtain their mirrored models. A 3D deviation analysis of a pelvic ring was conducted between the original model and its mirrored model via model registration and quantification of the geometric differences. Next, the pelvic rings were split to the left and right hipbones. The same flipping procedures as done by pelvic rings were performed for left hipbones to obtain their mirrored models. A 3D deviation analysis was also performed between the left and right hip bones. Quantitative variables representing deviation mainly included the average deviation (AD) and the maximum deviation (MD). MDs over 4 mm and 10 mm were deemed as critical levels for evaluating the severity of asymmetry as per Matta''s scoring system. The quantitative assessments of the asymmetry covered pelvic rings, bilateral hip bones and the specific anatomic regions of a hip bone.Results157 out of 159 pelvic rings (98.74%) had more than 4 mm of the MD and 27 (16.98%) of them exceeded 10 mm of the MD. The MD of pelvic rings was 1.23 times as high as that for the bilateral hip bones (7.46 mm vs. 6.08 mm, P < 0.05). The ADs of pelvic rings and bilateral hip bones were 1.28 mm and 0.94 mm, respectively (P < 0.05); 2.27% of the surface points of a pelvic ring had more than 4 mm geometric deviations compared with its mirrored model, while 0.59% (P < 0.05) of bilateral hip bones were on the same level of deviation. 119 out of 159 pelvic iliac crests (74.8%) had MDs more than 4 mm, and 15 (9.4%) reached 10 mm or more. Only 15 (9.4%) pelvises presented asymmetric features in the area of obturator foramen where the MDs exceeded 4 mm.ConclusionsPelvic asymmetry exists in the general population, but 3D geometric symmetry is present in specific anatomic regions. It implies that restoring the 3D symmetry of specific anatomic regions is more reliable than “restoring the symmetry of pelvic ring” in pelvic ring reduction or pelvic fixation design.     

Effects of Platelet‐Rich Plasma on Tendon‐Bone Healing After Anterior Cruciate Ligament Reconstruction

ObjectiveTo investigate the effect of platelet‐rich plasma on tendon‐bone healing after anterior cruciate ligament reconstruction.MethodsThis retrospective study included 85 patients (range, 18–50 years; mean age, 33.95 ± 10.53 years; male/female, 49/36) who underwent anterior cruciate ligament reconstruction using autologous hamstring tendons between August 2017 and June 2019 at our institute. The participants in the study group (n = 42) were injected with platelet‐rich plasma at both ends of the tendon graft, while those in the control group (n = 43) received an injection of normal saline. Magnetic resonance imaging signal/noise quotient values of the femoral and tibial ends, knee Lysholm scores, and International Knee Documentation Committee scores were compared at 3, 6, and 12 months postoperatively.ResultsThe signal/noise quotient values of the femoral and tibial ends in both groups were higher at 6 months than at 3 and 12 months postoperatively. The signal/noise quotient values of the tibial end were significantly lower in the platelet‐rich plasma group than in the normal saline group at all follow‐up time points (P < 0.05). The signal/noise quotient values of the tibial and femoral ends in both groups were significantly different at 3, 6, and 12 months postoperatively (P < 0.05). Additionally, the signal/noise quotient values of the tibia were significantly lower than those of the femur in both groups (P < 0.05). The Lysholm and International Knee Documentation Committee scores were significantly better in the platelet‐rich plasma group than in the normal saline group only at 3 months postoperatively. No complications, such as knee joint infection or vascular and nerve injuries, occurred in any of the 85 patients. The knee flexion of all patients were more than 90°, and the straight degree was 0°. No joint stiffness was observed in all patients.ConclusionPlatelet‐rich plasma can promote tendon‐bone healing in grafts and can improve early postoperative knee joint function.     

A Preoperative Predictive Model of Lower Lumbar Spine Instability Based on Three‐Dimensional Computed Tomography: A Retrospective Case–Control Pilot Study

ObjectiveThis study aimed to build a predictive model of lower lumbar instability.MethodsThis retrospective study included 199 patients. Patients were divided into the lower lumbar instability group (LLIG) (n = 98) and lower lumbar stability group (LLSG) (n = 101). All participants of LLIG were recruited over a 2‐year period (2015–2017) from the patients who accept lumbar surgery at the First Hospital of Jilin University. The LLSG was selected from outpatients who had underwent lumbar spine computed tomography (CT) and Flexion and extension radiographs (FER) at the First Hospital of Jilin University from 2015 to 2017. Several lower lumbar parameters were measured, including Lordosis angle (LA), intervertebral height (IH), ratio of anterior height to posterior height (APR), angle between endplate and anterior edge of vertebral body (AEPVa), sagittal slip ratio (SSR), and angle between the upper endplate and z‐axis on sagittal plane (AUEZS). These parameters were keyed into the SPSS software to create a predictive model for classification. Sensitivity, specificity, predictive accuracy, and Kappa value were used to evaluate the predictive model.ResultsCompared with LLSG, the LA of LLIG decreased by 3.49° (126.54° vs 130.3°). Similarly, the IH of LLIG decreased by 1.23°mm, 1.66°mm, and 0.71°mm at L3‐4, L4‐5, and L5‐S1. Compared with LLSG, the SSR of LLIG is higher at L3‐4, L4‐5, and L5‐S1 (0.54 vs 0.51, 0.57 vs 0.46, and 0.59 vs 0. 47). Moreover, the APR of LLIG is higher than those of LLSG at L3‐4, L4‐5, and L5‐S1 (1.97 vs 1.81, 2.40 vs 1.97, and 2.69 vs 2.26). The LLIG has bigger AEPVa than LLIG at L3‐4, L4‐5, and L5‐S1. Compared with LLSG, the AUEZS of LLIG is bigger at L3‐4 (91.75° vs 90.81°) and smaller at L4‐5 and L5‐S1(84.63° vs 85.85° and 73.27° vs 75.01°). The SSR (L4) show highest predictive accuracy (83%) when every parameter was fed to LDA classifier to generate a univariate model. All parameters represent a statistically significant difference (P < 0.05) between LLSG and LLIG. The model including LA, APR (L5‐S1), IH (L4‐5), SSR (L5), AUEZS (L5) has highest predictive accuracy of 88.2%. The sensitivity, specificity, and Kappa value are 88.7%, 93.1%, and 0.77.ConclusionThe predictive model has good classification performance and can be an auxiliary tool for clinicians to evaluate lumbar instability in preoperative patients with severe pain aggravated by lumbar movement.     

Non‐Anatomical Arthroscopic All‐Inside Repair of Medial Meniscus Posterior Root Tear to Posterior Cruciate Ligament for Patients with Normal Lower Limb Alignment

ObjectiveTo describe a non‐anatomical arthroscopic all‐inside repair of medial meniscus posterior root tear (MMPRT) to posterior cruciate ligament (PCL) technique for patients with normal lower limb alignment and to evaluate the short‐term clinical and radiologic outcomes.MethodsMMPRT directly to PCL was repaired with all‐inside horizontal mattress suturing technique rather than by the transtibial pullout suture technique or anchor suturing repair technique in 20 Laparade Type II MMPRT patients with normal lower limb alignment during 2018–2019. The clinical and radiological outcomes were evaluated retrospectively for at least 2 years follow‐up. The VAS score, Lysholm score, Tegner activity score were evaluated preoperatively and at the final follow‐up. The status of the medial meniscus posterior root were assessed on magnetic resonance imaging (MRI) preoperatively and at the final follow‐up.ResultsTwenty patients (mean age 54.5 ± 19.5 years) were included in the present study. The mean follow‐up duration was 32.5 ± 5.8 months. The VAS score was significantly decreased from preoperative 6.5 ± 1.5 to 2.1 ± 1.4 at the final follow‐up (P < 0.01). The mean Lysholm score was significantly improved from 43.7 ± 10.9 preoperatively to 85.7 ± 10.8 (P < 0.01). The median Tegner activity score was improved from 1.0 (range 1–4) to 3.0 (range 2–4, P < 0.01). On MRI, a total of 12 cases (60%) had complete healing, while eight cases (40%) had partial healing.ConclusionNon‐anatomical arthroscopic all‐inside repair of MMPRT to PCL may yield beneficial clinical outcomes and a higher rate of clinical healing in Type II MMPRT patients with normal lower limb alignment. It is an easy and reliable alternative technique to the transtibial pullout suture or anchor suture repair technique.     

Remnant Preservation is Helpful to Obtain Good Clinical Results in Posterior Cruciate Ligament Reconstruction: Comparison of Clinical Results of Three Techniques

Background

The purpose of the present study was to compare the clinical results of 3 posterior cruciate ligament reconstruction techniques according to the time from injury to surgery and remnant PCL status and to evaluate the efficiency of each technique.

Methods

The records of 89 patients who underwent primary PCL reconstructions with a posterolateral corner sling were analyzed retrospectively. Thirty-four patients were treated by anterolateral bundle (ALB) reconstruction with preservation of the remnant PCL using a transtibial tunnel technique in the acute and subacute stages of injury (group 1). Forty patients were treated with remnant PCL tensioning and an ALB reconstruction using the modified inlay technique in the chronic stage (group 2), and fifteen patients were treated with double-bundle reconstruction using the modified inlay technique (group 3). The double-bundle reconstruction was performed if there was a very weak or no PCL remnant.

Results

The mean side-to-side differences in posterior tibial translation on the stress radiographs were reduced from 10.1 ± 2.5 mm in group 1, 10.6 ± 2.4 mm in group 2, and 12.8 ± 3.2 mm in group 3 preoperatively to 2.3 ± 1.4 mm in group 1, 2.3 ± 1.5 mm in group 2, and 4.0 ± 2.5 mm in group 3 at the last follow-up (p < 0.001, p < 0.001, and p < 0.001, respectively). Statistical analyses revealed that group 1 and group 2 were similar in terms of side-to-side difference changes in posterior tibial translation on the stress radiographs; however, group 3 was inferior to group 1 and group 2 at the last follow-up (p = 0.022). The clinical results were not significantly different among the three groups.

Conclusions

Excellent posterior stability and good clinical results were achieved with ALB reconstruction preserving the injured remnant PCL in the acute and subacute stages and remnant PCL tensioning with ALB reconstruction in the chronic stage. The PCL injuries could be surgically corrected with different techniques depending on both the remnant PCL status and the interval between the knee trauma and operation.     

Intra‐Articular Biomechanical Changes of the Meniscus and Ligaments During Stance Phase of Gait Circle after Different Anterior Cruciate Ligament Reconstruction Surgical Procedures: A Finite Element Analysis

ObjectiveThe debate on the superiority of single‐ or double‐bundle for anterior cruciate ligament reconstruction has not ceased. The comparative studies on intra‐articular biomechanics after different surgical reconstructions are rare. This study is to evaluate the biomechanical stress distribution intra‐knee after single‐ and double‐bundle anterior cruciate ligament reconstruction by three‐dimensional finite element analysis, and to observe the change of stress concentration under the condition of vertical gradient loads.MethodsIn this study, magnetic resonance imaging data were extracted from patients and healthy controls for biomechanical analysis. Patients included in the three models were matched in age and sex. The strength and distribution of induced stresses were analyzed in two frequently used procedures, anatomical single‐bundle anterior cruciate ligament reconstruction and anatomical double‐bundle anterior cruciate ligament reconstruction, using femoral‐graft‐tibial system under different loads, to mimic a post‐operation mechanical motion. The three‐dimensional finite‐element models for normal ligament and two surgical methods were applied. A vertical force simulating daily walking was performed on the models to assess the interfacial stresses and displacements of intra‐articular tissues and ligaments. The evaluation results mainly included the stress of each part of ligament and meniscus. The stress values of different parts of three models were extracted and compared.ResultsThe stress of ligament/graft at femoral side of three finite‐element models was significantly higher than at tibial side, while the highest level was observed in single‐bundle reconstruction finite‐element model. With the increase of force, the maximum stress in the medial (7.1–7.1 MPa) and lateral (4.9–7.4 MPa) meniscus of single‐bundle reconstruction finite‐element model shifted from the anterior horn to the central area (p = 0.0161, 0.0479, respectively). The stress was shown to be at a lower level at femoral side and posterior cruciate ligament of intra‐knee in two reconstruction finite‐element models than that in normal finite‐element models, while presented higher level at the tibial side than normal knee (p = 0.3528). The displacement of the femoral side and intra‐knee areas in reconstruction finite‐element models was greater than that in normal finite‐element model (p = 0.0855).ConclusionCompared with the single‐bundle technique, the graft of double‐bundle anterior cruciate ligament reconstruction has better stress dissipation effect and can prevent postoperative meniscus tear more effectively.     

Three‐Dimensional Printing‐Assisted Masquelet Technique in the Treatment of Calcaneal Defects

ObjectiveThe aim of the present study was to summarize the clinical efficacy of three‐dimensional (3D) printing technology combined with the Masquelet technique in the treatment of calcaneal defects.MethodsFrom January 2018 to April 2019, 3D printing combined with induced masquelet technology was used to treat four patients with calcaneal defects, including two men and two women. The patients were aged 22–52 years old, with an average age of 36 years. There were two cases of traffic accident injuries, there was one case of a fall from height, and there was one case of crush injury. CT scans were used to reconstruct the bilateral calcaneus, mirror technology was used to construct the bone defect area, and Materialise 3‐matic software was used to design the calcaneus shaper mold and 3D print the mold. During the operation, the mold was used to shape the bone cement and fill the bone defect. In the second stage, the bone cement was removed and autologous bone was implanted to repair the bone defect. All patients were followed up to observe the effect.ResultsAll four patients were followed up for 14 months (range, 10–18 months). There were three cases of infectious bone defects: two cases of Escherichia coli and one case of Pseudomonas aeruginosa. The 3D printed mold was used to shape the bone cement. During the operation, it was found to have a high degree of matching with the defect area of calcaneus. There is no need to adjust it again, and the wound healed well after the first stage. In the second stage of surgery, it was found that the induced membrane formed was complete and of appropriate size; the bone cement was easily removed during the operation. The fracture healing time was 3–6 months, with an average of 4 months. At the last follow up, there was no pain and the patients walked with full weight bearing. The Maryland score was 94 points (range, 88–98 points); three cases were excellent and one case was good. The AOFAS score ranged from 86 to 98, with an average of 92.8 points; three cases were excellent and one case was good.ConclusionThree‐dimensional printing technology combined with induced membrane technology is an effective approach for treating calcaneal bone defects.