Patellar height and the inclination of the tibial plateau after high tibial osteotomy. The open versus the closed-wedge technique

Surgical strategy and complication management of osteotomy around the painful degenerative varus knee: ESSKA Formal Consensus Part II

PURPOSE

The purpose of the European consensus was to provide recommendations for the treatment of patients with a painful degenerative varus knee using a joint preservation approach. Part II focused on surgery, rehabilitation and complications after tibial or femoral correction osteotomy.

METHODS

Ninety-four orthopaedic surgeons from 24 countries across Europe were involved in the consensus, which focused on osteotomies around the knee. The consensus was performed according to the European Society for Sports Traumatology, Knee Surgery and Arthroscopy consensus methodology. The steering group designed the questions and prepared the statements based on the experience of the experts and the evidence of the literature. The statements were evaluated by the ratings of the peer-review groups before a final consensus was released.

RESULTS

The ideal hinge position for medial opening wedge high tibial osteotomy (MOW HTO) should be at the upper level of the proximal tibiofibular joint, and for lateral closing wedge distal femoral osteotomy (LCW DFO) just above the medial femoral condyle. Hinge protection is not mandatory. Biplanar osteotomy cuts provide more stability and quicker bony union for both MOW HTO and LCW DFO and are especially recommended for the latter. Osteotomy gap filling is not mandatory, unless structural augmentation for stability is required. Patient-specific instrumentation should be reserved for complex cases by experienced hands. Early full weight-bearing can be adopted after osteotomy, regardless of the technique. However, extra caution should be exercised in DFO patients. Osteotomy patients should return to sports within 6 months.

CONCLUSION

Clear recommendations for surgical strategy, rehabilitation and complications of knee osteotomies for the painful degenerative varus knee were demonstrated. In Part 2 of the consensus, high levels of agreement were reached by experts throughout Europe, under variable working conditions. Where science is limited, the collated expertise of the collaborators aimed at providing guidance for orthopaedic surgeons developing an interest in the field and highlighting areas for potential future research.

LEVEL OF EVIDENCE

Level II, consensus.

Changes in Patellar Height and Tibial Posterior Slope after Biplanar High Tibial Osteotomy with Computer-Designed Personalized Surgical Guides: A Retrospective Study

OBJECTIVE

Medial opening-wedge high tibial osteotomy (MOWHTO) is a surgical procedure to treat medial compartment osteoarthritis in the knee with varus deformity. However, factors such as patellar height (PH) and the sagittal plane's posterior tibial slope angle (PTSA) are potentially overlooked. This study investigated the impact of alignment correction angle guided by computer-designed personalized surgical guide plate (PSGP) in MOWHTO on PH and PTSA, offering insights for enhancing surgical techniques.

METHODS

This retrospective study included patients who underwent 3D-printed PSGP-assisted MOWHTO at our institution from March to September 2022. The paired t-tests assessed differences in all preoperative and postoperative measurement parameters. Multivariate linear regression analysis examined correlations between PTSA, CDI (Caton-Deschamps Index), and the alignment correction magnitude. Receiver operating characteristic (ROC) curve analysis determined the threshold of the correction angle, calculating sensitivity, specificity, and area under the curve.

RESULTS

A total of 107 patients were included in our study. The CDI changed from a preoperative mean of 0.97 ± 0.13 (range 0.70-1.34) to a postoperative mean of 0.82 ± 0.13 (range 0.55-1.20). PTSA changed from a preoperative mean of 8.54 ± 2.67 (range 2.19-17.55) to a postoperative mean of 10.54 ± 3.05 (range 4.48-18.05). The t-test revealed statistically significant changes in both values (p < 0.05). A significant alteration in patellar height occurred when the correction angle exceeded 9.39°. Moreover, this paper illustrates a negative correlation between CDI change and the correction angle and preoperative PTSA. Holding other factors constant, each 1-degree increase in the correction angle led to a 0.017 decrease in postoperative CDI, and each 1-degree increase in preoperative PTSA resulted in a 0.008 decrease in postoperative CDI. PTSA change was positively correlated only with the correction angle; for each 1-degree increase in the opening angle, postoperative PTS increased by 0.188, with other factors constant.

CONCLUSION

This study highlights the effectiveness and precision of PSGP-assisted MOWHTO, focusing on the impact of alignment correction on PH and PTSA. These findings support the optimization of PSGP technology, which offers simpler, faster, and safer surgeries with less radiation and bleeding than traditional methods. However, PSGP's one-time use design and the learning curve required for its application are limitations, suggesting areas for further research.

Femoral trochlear groove cartilage damage after open-wedge high tibial osteotomy is associated with the change in patellar height relative to the femoral condyle

BACKGROUND

Medial open-wedge high tibial osteotomy (OWHTO) is performed for isolated medial compartment osteoarthritis or osteonecrosis of the knee and correction of varus deformity of the full lower extremity. OWHTO may induce sagittal parameter changes, including these in the tibial posterior slope (TPS), patellar height (PH), and patellofemoral joint problems. This study aimed to identify radiographic parameters associated with patellofemoral cartilage damage after OWHTO.

HYPOTHESIS

The patellofemoral joint cartilage worsens after OWHTO and is adversely affected by PH changes.

PATIENTS AND METHODS

Twenty patients (25 knees) who underwent primary OWHTO and subsequent implant removal surgery, including second-look arthroscopy for evaluation of the patellofemoral cartilage condition were enrolled. The patients were received 12 to 35 months of postoperative follow-up, and categorized into two groups according to whether patellofemoral cartilage damage worsened. TPS and PH parameters, including the Insall-Salvati, Blackburne-Peel, Caton-Deschamps, and modified Blumensaat (MBI) indices, were measured on lateral knee radiographs. The hip-knee-ankle and medial proximal tibial angles were measured using an anteroposterior radiograph of the full lower extremity. The extent of change from preoperative to postoperative (Δ) was calculated for all indices.

RESULTS

Eleven knees (44%) had worsening cartilage conditions in the femoral trochlear groove, with>1-degree of deterioration in the International Cartilage Repair Society grade. The radiographic measure for predicting patellofemoral cartilage deterioration was ΔMBI (95% confidence interval [CI]: 3.53×10-14-0.812, p=0.047). PF cartilage damage tended to progress in ΔMBI<-0.145. The postoperative TPS and HKAA in patients with deterioration in patellofemoral cartilage damage was greater than that in patients without deterioration in patellofemoral cartilage damage (p=0.037 and 0.038, respectively).

DISCUSSION

The patellofemoral cartilage damage tends to progress after OWHTO. ΔMBI is a factor for predicting worsening patellofemoral cartilage condition. However, attention should be paid to the excessive posterior slope as high TPS and valgus alignment as valgus HKAA because intraoperative control of MBI is impossible.

LEVEL OF EVIDENCE

IV, retrospective study.

The Influence of Tibial Tubercle-Sparing Slope-Reducing Osteotomy on Patellar Height in Patients Undergoing Revision ACL Reconstruction

BACKGROUND

A posterior tibial slope (PTS) >12° is an independent risk factor for anterior cruciate ligament (ACL) graft rupture, and a high tibial osteotomy (HTO) for slope correction can help avoid it. Management of patellar height is of major concern when performing HTO.

PURPOSE

To evaluate the effect of tibial tubercle-sparing anterior closing-wedge osteotomy on patellar height in revision ACL reconstruction (ACLR).

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients who underwent arthroscopic revision ACLR combined with retro-tibial tubercle anterior closing-wedge HTO (ACW-HTO) between January 1, 2016, and March 31, 2021, were assessed for eligibility. Patellar height was measured on full weightbearing lateral radiographs according to the Insall-Salvati index (ISI) and Caton-Deschamps index (CDI) or frontal radiographs using the femoral patellar height index. The PTS was evaluated using the proximal anatomic axis of the tibia on standard short lateral radiographs. The delta (postoperative - preoperative) and the ratio (preoperative/postoperative) of the 3 patellar height indices and PTS were calculated. Preoperative and postoperative patellar heights were compared using independent t tests for each index. Also investigated was whether patients changed patellar height category (baja, normal, or alta) after slope osteotomy.

RESULTS

Among 475 revision ACLRs, 47 tibial tubercle-sparing ACW-HTOs were retained for analysis. No significant difference in patellar height was found between pre- and postoperative radiographs regardless of the index (preoperative - postoperative) (ISI: 1.0 ± 0.2 - 0.9 ± 0.2, P = .1729; CDI: 1.0 ± 0.2 - 1.0 ± 0.2, P = .4034; femoral patellar height index: 1.5 ± 0.2 - 1.5 ± 0.2; P = .5130). Fifteen patients (31.9%) exhibited a postoperative change in their patellar height category when measured by the ISI (6 moved up a category, 9 moved down one), and 18 patients (38.3%) changed category according to the CDI (10 moved up a category, 8 moved down one). No significant difference was found between pre- and postoperative patellar height among these patients (ISI: P = .2418; CDI: P = .3005).

CONCLUSION

Changes in patellar height ratio are common after tibial tubercle-sparing ACW-HTO in patients undergoing revision ACLR. The clinical effect of these changes is unknown, and further study is needed to investigate whether they may result in patellofemoral symptoms.

Angle Stable Plate Fixation vs Hemicallotasis in Medial Opening Wedge High Tibial Osteotomy: A Comparative Study

Background

Varus alignment associated with medial compartment degeneration is the most common presentation of knee osteoarthritis and often presents in young active adults where arthroplasty might be unsuitable.

Purpose

To compare the accuracy of the angle stable medial high tibia plate and self-adjusting HTO (high tibial osteotomy) fixator in achieving correction of varus deformity of the knee by medial opening wedge HTO and to evaluate functionality between the groups.

Study Design

Prospective randomized control study.

Methods

Forty patients each underwent medial opening wedge high tibial osteotomy with acute correction and stabilization using the angle stable plate (ASP group) or with the hemicallotasis technique using the self-adjusting HTO external fixator (HCO group). Anatomical and functional outcomes were compared to the pre-operative values at the 6th and 12th month.

Results

The FTA (femoro-tibial axis), mechanical axis, and functional scores improved significantly in both groups. There was also a significant change in the patellar height and tibial slope. Except for a better KOOS (Knee Injury and Osteoarthritis Outcome Score) in the angle stable plate group at the 6-month follow-up, there were no significant differences between the groups.

Conclusion

Both methods of performing a medially based proximal tibial osteotomy gave equivalent outcomes at the 1-year follow-up.

Clinical and radiological outcomes of medial opening-wedge monoplanar and biplanar high tibial osteotomy using a triangular allograft impaction technique: A retrospective single centre study

PURPOSE

The aim of the study was to research the clinical and radiological outcomes between monoplanar and biplanar medial opening-wedge high tibial osteotomy. We hypothesized that there would be no differences between both techniques when using a triangular allograft impaction technique.

METHODS

A single-centre, observational, retrospective study was conducted on 103 opening-wedge high tibial osteotomy patients from January 2017 to September 2019. Data collection, NRS and KOOS-PS, was performed preoperatively, 3 months and 12 months postoperatively. Radiological assessment (Kellgren-Lawrence, mechanical femoral-tibial angle, posterior tibial slope angle, lateral patellar tilt, patellar height) was performed on standing radiographs.

RESULTS

In total 32 patients were included in the biplanar group and 71 patients in the monoplanar group. NRS and KOOS-PS scores improved significantly (p < 0.001) in time for both groups from baseline to 3 m PO and further to 1 year postoperatively. Our results showed no differences in radiological outcomes such as patellar height, LPT and posterior tibial slope angle. The monoplanar group did have more Takeuchi I and III fractures and a higher mFTA angle without clinical repercussion.

CONCLUSIONS

Using a triangular allograft impaction technique for monoplanar and biplanar medial opening-wedge high tibial osteotomy gives no differences in clinical (NRS and KOOS) and radiological outcomes. Although a difference in Takeuchi fractures was found for monoplanar patients, no additional fixation was necessary, nor did clinical complications occur. We can conclude that triangular allograft impaction technique creates a stable construct and standardizes the healing procedure postoperatively for both monoplanar and biplanar medial opening-wedge high tibial osteotomy.

Open wedge high tibial osteotomy does not decrease patellar height relative to femur: A three-dimensional computer model analysis

BACKGROUND

Patellar height, which decreases after open wedge high tibial osteotomy (OWHTO), has conventionally been assessed by tibial references using lateral radiographs of the knee; however, changes in the proximal tibia shape after OWHTO may affect this method. We aimed to evaluate the changes in patellar height position relative to the transepicondylar axis of the femur after OWHTO using in vivo three-dimensional (3D) computer models.

METHODS

Fourteen patients who underwent 3D magnetic resonance imaging (MRI) at 30° and 50° knee flexion before OWHTO and after hardware removal were included. 3D computer models of the knee were created from the MRI scans and superimposed over the images taken in each position using voxel-based registration. For patellar height evaluation, a patellar reference point was established at each flexion angle and the femoral condylar planes (FCP) were set, including the transepicondylar axis. The patellar center angle was defined as the angle between an FCP that included the top of the intercondylar notch and an FCP that included the patellar reference point. The patellar center angle was evaluated at 30° and 50° knee flexion before and after OWHTO.

RESULTS

The patellar center angle at 30° and 50° knee flexion did not significantly decrease after OWHTO, whereas the Caton-Deschamps index and Blackburne-Peel index based on tibia-referenced measurements significantly decreased postoperatively.

CONCLUSION

Patellar height position relative to the femur in the 3D computer model did not decrease after OWHTO, whereas tibia-referenced conventional radiographic measurements significantly decreased. When evaluating patellar height, characteristics of each parameter should be considered.

Is proximal tibial tubercle osteotomy superior to distal tibial tubercle osteotomy for medial compartmental osteoarthritis? A meta-analysis

BACKGROUND

Open-wedge high tibial osteotomy (OWHTO) is commonly performed for the treatment of medial compartment knee osteoarthritis (KOA), and is classified into proximal tibial tubercle osteotomy (PTO) and distal tibial tubercle osteotomy (DTO). The PTO osteotomy point is generally located about 3-4 cm below the joint of the proximal tibia, and the osteotomy line points to the upper part of the proximal tibiofibular joint. The DTO osteotomy point is generally located about 0.5-1.0 cm below the tibial tubercle, and the osteotomy line points to the contralateral cortex. However, there is currently no consensus on which surgical technique is superior. The purpose of our study was to investigate which among the two is superior for medial KOA, with respect to knee joint parameters, clinical function, and complications.

METHODS

This study was conducted as per the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The Cochrane Central Library, MEDLINE, Embase, PubMed, CNKI, and WanFang databases were systematically searched for trials comparing PTO and DTO in patients with medial compartment KOA, from inception until March 2022. The meta-analysis was conducted using RevMan 5.2 software. The Cochrane risk-of-bias tool was used to assess methodological quality. Statistical analysis was performed with Stata 12.0. Outcomes of interest included the Insall-Salvati index (ISI), Caton-Deschamps index (CDI), Blackburne-Peel index (BPI), posterior tibial slope (PTS), and the Hospital for Special Surgery (HSS) knee-rating scale.

RESULTS

A total of 15 retrospective studies (910 knees) were included. There were no significant differences in the age or sex of included patients. There was a significant difference in the ISI, CDI, BPI, and PTS between the two groups (all p ≤ 0.05). Further, DTO was associated with a significantly greater number of postoperative complications (p < 0.05) compared to PTO. However, there was no significant difference in the femorotibial angle (FTA), mechanical medial proximal tibial angle (mMPTA), and HSS knee score (all p > 0.05).

CONCLUSIONS

Compared with DTO, PTO is associated with a greater incidence of postoperative patella baja and increased PTS, whereas DTO is associated with more postoperative complications. Nevertheless, both can significantly correct knee varus deformity and improve knee function; their early knee function scores are also similar.

TRIAL REGISTRATION

Prospective Register of Systematic Reviews (PROSPERO) registration number CRD42021284443.

Preoperative overweight and obesity do not cause inferior outcomes following open-wedge high tibial osteotomy: A retrospective cohort study of 123 patients

Open-wedge high tibial osteotomy (OWHTO) is effective in treating medial compartment osteoarthritis. The association between body mass index (BMI) and outcomes following OWHTO is being debated. This study compared radiographic and clinical outcomes between patients with preoperative overweight, obesity, and normal BMI following OWHTO for medial compartment osteoarthritis. In total, 123 patients (123 knees) who underwent OWHTO for medial compartment osteoarthritis were enrolled and were divided into normal-BMI (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), and obese (>30 kg/m2) groups based on body mass index. The numeric rating scale for pain, mechanical tibiofemoral angle (mTFA), tibia tilting angle (TTA), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) for function were evaluated preoperatively and at postoperative follow-ups. The improvements of clinical and radiological outcomes in normal-BMI, overweight, and obese groups were not significantly different. The incidence of soft tissue irritation, wound infection, nonunion, and conversion to total knee arthroplasty were not significantly different between groups.The clinical and radiological outcomes in patients with preoperative overweight, obesity, and normal-BMI were not significantly different. Preoperative overweight and obesity thus has no effect on outcomes following OWHTO during the two years follow-up period. These findings cannot be generalized to patients with morbid obesity.

The effects of open wedge high tibial osteotomy for knee osteoarthritis on the patellofemoral joint. A systematic review

BACKGROUND (INCLUDING AIMS OF THE STUDY)

To investigate the impact medial opening wedge high tibial osteotomy (MOWHTO) has on the progression of patellofemoral (PF) OA, patella height, contact pressure within the PF joint and clinical outcomes.

METHODS

A systematic review was conducted in January 2022 according to PRISMA guidelines. The ICRS cartilage grade of the PF joint at the initial MOWHTO surgery and at second look surgery was compared and relative risk of progression of PF OA was calculated. Evaluation of patella height was assessed by Caton-Deschamps index, Blackburne-Peel index or Insall-Salvati index pre and post MOWHTO. Cadaveric studies assessing contact pressures in the PF after MOWHTO were included.

RESULTS

Forty-two studies comparing 2419 patients were included. The mean age was 53.1 years (16-84), 61.3% female. The risk of progression of PF OA was highest in the uniplanar and biplanar MOWHTO with proximal tubercle osteotomy groups (RR = 1.28-1.51) compared to biplanar MOHWTO with distal tubercle osteotomy (RR = 0.96-1.04). Patella height was not affected after biplanar MOWHTO with distal tubercle osteotomy (p < 0.001). Cadaveric studies demonstrate that PF contact pressures increase with more severe corrections (15°) but suggest biplanar MWOHTO and distal tubercle osteotomy induces lower contact pressures within the PF joint than other MOWHTO techniques. Significant over correction is associated with worse clinical outcomes and anterior knee pain.

CONCLUSION

Biplanar MOWHTO and distal tubercle osteotomy has minimal effect on the contact pressures in the PF joint resulting in less severe progression of PF OA and has minimal impact on patella height.

Opening- and closing-wedge high tibial osteotomy are comparable and early full weight bearing is safe with angular stable plate fixation: a meta-analysis

PURPOSE

The purpose of this study was to establish the gold standard for surgical technique, fixation, and rehabilitation for HTO in patients with unicompartmental knee osteoarthritis.

METHODS

Medline, Embase, and SPORTDiscus databases were searched up to April 2022. Included were (1) randomized controlled trials (RCTs) comparing opening-wedge HTO (owHTO) and closing-wedge HTO (cwHTO), (2) biomechanical studies and prospective patient studies comparing biomechanical and clinical results for plate fixators, and (3) RCTs comparing an early versus delayed full-weight-bearing (FWB) protocol.

RESULTS

The pooled results for the surgical technique showed no significant differences between owHTO and cwHTO for most PROMs on pain, activity, and risk for conversion to TKA. The cwHTO group showed a slightly better improvement in KOOS/WOMAC pain scores (4.51; 95% CI 1.18-7.85), and a significantly lower change in posterior tibial slope (p = 0.03). The pooled results for the fixation method showed the highest force at maximum failure for the Activmotion (Newclip Technics, France), Aescula (B. Braun Korea, Korea), 2nd generation Puddu (Arthrex Inc., USA), and TomoFix plate (Depuy Synthes, Switzerland). The pooled results for the rehabilitation protocol showed no significant differences between the early full-weight-bearing (FWB) group and the delayed FWB group for functional scores, complication rates, and delayed unions.

CONCLUSION

Both owHTO and cwHTO reduced pain and improved knee function. Locking plate fixation should be used for owHTO. An early FWB protocol has proven to be safe in patients with small corrections, no hinge fractures, and non-smokers.

LEVEL OF EVIDENCE

Level II.

Changes in patellar baja progress until 3 months after medial open-wedge high tibial osteotomy

PURPOSE

The purpose of this study was to evaluate sequential patellar height changes as well as the factors leading to these changes after medial open-wedge high tibial osteotomy (MOWHTO).

METHODS

The study cohort constituted 37 knees from 36 patients who underwent MOWHTO for varus knee. The Caton-Deschamps index (CDI) for patellar height was measured preoperatively and at 2 weeks and 3, 6, and 12 months postoperatively. The factors related to sequential changes in patellar height were evaluated.

RESULTS

Significant differences were observed between preoperative CDI and postoperative CDI at all time points (p < .05). Two-week postoperative CDI and postoperative CDI at 3,6,12-months was also significantly different (p < .05). The only significant factor for the change in patellar height between preoperative CDI and postoperative CDI at 2-weeks and 12-months was the change in the Δ medial proximal tibial angle (ΔMPTA) (postoperative MPTA-preoperative MPTA). We could not identify the factor that affected the change in patellar height change from 2-weeks postoperatively.

CONCLUSION

The change in patellar height continued sequentially until at least 3 months postoperatively. ΔMPTA was associated with the change in patellar height at 2 weeks postoperatively compared with preoperatively; however, no factors associated with the change in patellar height from 2 weeks postoperatively to 3, 6, and 12-months postoperatively were identified.

Anterior Closing-Wedge High Tibial Osteotomy Using Patient-Specific Cutting Guide in Chronic Anterior Cruciate Ligament-Deficient Knees

An increased posterior tibial slope has been identified as an independent risk factor for anterior cruciate ligament (ACL) graft rupture, with a critical threshold of 12°. Surgical slope correction by anterior closing wedge (ACW)-high tibial osteotomy (HTO) can reduce ACL force and anterior tibial translation with good clinical outcomes when combined with revision ACL reconstruction. Performing ACW-HTO preserving the tibial tubercule can be challenging for inexperienced surgeons. Patient-specific cutting guides have been shown to be effective in facilitating the surgeon's learning curve in medial opening wedge-HTO by reducing operative time and the use of fluoroscopy as well as decreasing anxiety. The present technique describes a retro-tibial tubercule ACW-HTO using a patient-specific cutting guide.

New insight into the current study of high tibial osteotomy: A bibliometric analysis

BACKGROUND

To analyze global trends in focus and funding of research related to high tibial osteotomy (HTO) and to identify the 100 most cited articles in this field.

METHODS

A Web of Science search was used to identify HTO publications in English-language scientific journals from January 1967 till February 3th, 2021. Results were filtered to the 100 most cited articles by reading the abstract or full-text paper. Information of these articles was recorded for further analysis. The 10 top-cited articles during the last 5 years and the 10 top-cited articles about HTO ranked by average citations per year were selected to predict research trends.

RESULTS

In all, 48 out of the 100 top-cited articles were published between 2000 and 2010. The United States of America was the primary contributor (n = 29) followed by Germany (n = 17) and Japan (n = 11). The total number of citations per article ranged from 65 to 563, median 108, mean 135 (standard deviation = 84). The American Journal of Bone and Joint Surgery accounted for 23 out of the 100 top-cited articles. Koshino T was the most cited author (603 citations). The most frequently highlighted study theme was prognostic research. Patient-based clinical research was the dominant study design (85%). The majority of articles (48 out of 100) were level IV evidence with a mean of 141 (standard deviation = 97) citations. Top-cited articles in the last 5 years focused on open wedge osteotomy.

CONCLUSION

Technical optimization of open wedge osteotomy has emerged as the main area of research in HTO. More specifically, recent publications focus on the surgical technology, cartilage repair and new fixation devices. Besides, papers with a high level of evidence are needed for the development of HTO.

A biomechanical study: Comparison of three different implant options in high Tibial osteotomy

BACKGROUND

Many implant options could be preferable for fixation after osteotomy in varus knee medial compartment arthrosis. Due to usage characteristics, it is important to compare the biomechanical properties of them. For this purpose, we aimed to examine three different implant types biomechanically in our study.

METHODS

Ovine tibiae undergoing medial open-wedge high tibial osteotomy were fixed in vitro with three different implants using an angular wedge plate, a metal block plate and an external fixator system. The fixed ovine tibiae were subjected to axial tensile, axial loading and three-point bending tests in a test machine. All biomechanical tests were repeated five times, the maximum and minimum values were ignored, and the average values of the remaining three test results were taken into account. The test results were interpreted after converted into force-elongation curves in Trapezium-X software.

FINDINGS

Biomechanical test results revealed some differences between implant types. While the metal block plate had the highest axial tensile strength value, it was the fixation group showing the lowest strength in axial load tests. The used fixator system was the highest strength in axial load tests and the lowest strength in axial tensile tests.

INTERPRETATION

Considering the clinically significant forces related to the biomechanical stability of the three different implants used for high tibial osteotomy, the fixator system would appear to be slightly superior, although it should be noted that torsional forces, as well as parameters that could change in living tissue, might affect the results.

Effect of the Inverted V-Shaped Osteotomy on Patellofemoral Joint and Tibial Morphometry as Compared With the Medial Opening Wedge High Tibial Osteotomy

BACKGROUND

Recent studies have reported that medial opening wedge (OW) high tibial osteotomy (HTO) induces patella baja, resulting in degenerative changes in the patellofemoral joint. We have developed an inverted V-shaped (iV) HTO, which is classified as a neutral wedge osteotomy.

HYPOTHESES

The study hypotheses were as follows: (1) patellar height, posterior tibial slope, and tibial length will not change between pre- and postoperative evaluations after iV-HTO; (2) the lateral shift ratio of the patella and the distance between the tibial tubercle and the trochlear groove may be significantly decreased after iV-HTO.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 191 patients (220 knees) who underwent HTO for medial osteoarthritis were enrolled retrospectively in this study: 107 knees underwent OW-HTO and 113 knees underwent iV-HTO. Clinical and radiological evaluations were performed before and at least 3 years after surgery.

RESULTS

Postoperatively, the mean Caton-Deschamps ratio was significantly decreased (P < .0001) from 0.95 to 0.79 in the OW group, while there were no significant changes in the iV group. The mean posterior tibial slope was significantly increased (P < .0001) from 8.5° to 10.5° in the OW group, while there were no significant differences in the iV group. Although the entire leg length was significantly increased (P < .0003) in both groups after HTO, there were no significant differences in tibial length between the pre- and postoperative periods in the iV group. Regarding the congruity of the patellofemoral joint, the mean lateral shift ratio did not significantly change in the OW group, whereas it was significantly decreased (P = .0012) from 11.5% to 8.8% in the iV group. The mean tibial tubercle-trochlear groove distance was significantly decreased (P < .0001) from 12.8 to 9.7 mm in the iV group, while it was significantly increased in the OW group (P < .0001). Concerning the clinical outcome, the Japanese Orthopaedic Association (JOA) and Lysholm knee scores at final follow-up (OW vs iV: JOA, 91.2 vs 90.1; Lysholm, 92.5 vs 89.0) were significantly increased (P < .0001) as compared with the preoperative values (OW vs iV: JOA, 68.3 vs 66.8; Lysholm, 67.9 vs 61.0).

CONCLUSION

Patellar height, posterior tibial slope, and tibial length did not change after the iV-HTO, while they were significantly changed after the OW-HTO. Although the preoperative degrees of varus knee and patellofemoral osteoarthritis were more severe in the iV group than the OW group, the iV-HTO led to altered patellofemoral joint congruity.

The influence of different hinge position on PTS during HTO: comparison between open-wedge and closed-wedge HTO

PURPOSE

The purpose of this study was to determine the significance of hinge position through comparison between open-wedge and closed-wedge high tibial osteotomy (HTO) and to determine the ideal hinge position to minimize the effect of HTO on the posterior tibial slope (PTS) and medial proximal tibial angle (MPTA).

METHODS

Procedures were performed on 32 cadaveric knees using open-wedge HTO with the standard hinge position or a low hinge position or closed-wedge HTO with the standard hinge position or a low hinge position. To define the standard hinge position in open wedge HTO, we drew a line 3-cm inferior to the medial tibial plateau toward the fibular head and located the intersection of this line with a longitudinal line 1-cm medial to fibular shaft. The low hinge position was then defined as the point 1-cm inferior to the standard position. For the standard hinge position for closed-wedge HTO, we drew a line parallel with joint line from 2-cm inferior to the lateral tibial plateau. The low hinge position was then defined as the point 1-cm inferior to the standard position.

RESULTS

For the open-wedge procedure, osteotomy through the low hinge position resulted in a significantly greater PTS compared to osteotomy through the standard hinge position. MPTA was also significantly greater for the low hinge position compared to standard hinge position. In the closed-wedge HTO, neither the PTS nor MPTA was significantly different for the low and standard hinge positions.

CONCLUSIONS

Hinge position significantly affects changes in the PTS and MPTA following open-wedge but not closed-wedge HTO. Understanding how to hinge position affects the PTS and MPTA is critical for surgeons performing open-wedge HTO procedures. Adopting an accurate hinge position is crucial for preventing complications, especially in open-wedge osteotomy, due to postoperative changes in the PTS and MPTA.

A novel 3D-printed patient-specific instrument based on "H-point" for medial opening wedge high tibial osteotomy: a cadaver study

BACKGROUND

Opening wedge high tibial osteotomy (OWHTO) is an effective surgical treatment for knee osteoarthritis. This study aimed to explore the feasibility and accuracy of a novel 3D-printed patient-specific instrument (PSI) based on "H-point" for medial OWHTO in a prospective cadaver study.

METHODS

Twenty-six fresh-frozen lower limbs were collected and randomly divided into two groups: PSI group treated with 3D virtual preoperative planning and a novel 3D-printed PSI; control group with the standard technique. 3D models were reversely reconstructed for preoperative surgical planning, guide plate design, and simulated osteotomy. Anatomic features of "H-point," surgical time, fluoroscopic dose, correction accuracy including tibiofemoral angle (FTA) and posterior tibial slope (TS) angle were measured.

RESULTS

First, H-point was always described as a bony bulge in the posteromedial to the proximal tibia and had a relatively constant relationship with the osteotomy site. Second, the absolute correction error of mFTA and TS were significantly smaller in the PSI group. The effective rate of TS in the PSI group was more concentrated with absolute correction error within 1° and within 2° for 53.3% and 93.3%, compared to 9.1% and 45.5% in the control group. The total operation time, positioning osteotomy time, distraction correction time and fluoroscopy dose in the PSI group were significantly less than those in the control group.

CONCLUSIONS

The novel 3D-printed PSI based on H-point is feasibility and accuracy with advantages in terms of TS, surgery time and radiation dose for OWHTO.

Feasibility and 3D Planning of a Novel Patient-Specific Instrumentation Technique in Medial Opening-Wedge High Tibial Osteotomy

A novel approach for opening-wedge high tibial osteotomy (OWHTO) with patient-specific instrumentation (PSI) was evaluated for its safety, feasibility, and accuracy. Next, the mechanical medial proximal tibial angle (mMPTA) was assessed as a potential planning angle by investigating the relation with the mechanical femorotibial angle (mFTA). Ten OWHTO cases were 3D planned using the mMPTA and operated with a customized 3D-printed wedge and cast which resembled the intended osteotomy opening. Patients were closely monitored for intraoperative and postoperative complications up to 1 year after surgery. Radiological assessment was conducted on full leg standing radiographs and supine lower limb computed tomography-scans preoperatively and 3 months after surgery. No intraoperative complications or logistical issues during PSI processing were observed. Absolute accuracy outcomes showed a correction error of 1.3° ± 1.1 mMPTA and 0.9° ± 0.6 mFTA with all osteotomies falling in (-2°; + 2°) mFTA around the target. The mMPTA and mFTA were found to have a strong correlation in both 3D (r = 0.842, p = 0.002) and 2D (r = 0.766, p = 0.01) imaging for effective correction. The study confirmed the development of a safe and feasible PSI technique in OWHTO with excellent accuracy outcomes. The strong correlation between the mMPTA and mFTA indicated that soft tissue changes after OWHTO are of minor significance to the final alignment in ligament-stable patients. Finally, the mMPTA was found to be a reliable planning angle in 3D software for obtaining the intended lower limb realignment and its use can therefore be recommended in modern OWHTO planning.

Does arthroscopic patellar denervation with high tibial osteotomy improve anterior knee pain?

PURPOSE

Patellofemoral (PF) joint osteoarthritis (OA) is a major cause of anterior knee pain. Combined PF and medial tibiofemoral (TF) OA is common in older adults. We evaluated the effect of arthroscopic patellar denervation (PD) in patients with combined TF and PFOA after malalignment correction.

METHODS

Forty-five patients [females/males, 27/18; age, 30-59 years (45.5 ± 8.50); mean body mass index, 25.15 ± 3.04 kg/m²] were treated in our department from March 2017 to March 2019. The patients were randomised into 2 groups: group A included 22 patients who underwent open-wedge high tibial osteotomy (OWHTO) and arthroscopic PD and group B included 23 patients who underwent OWHTO without denervation. The effect of denervation was statistically and clinically evaluated using the Knee injury and Osteoarthritis Outcome Score (KOOS) and Kujala (anterior knee pain score) score.

RESULTS

After 24 months, 40 patients were available for the final follow-up. The final values of KOOS and the Kujala score were significantly different between the groups (p < 0.001). For group A, the average KOOS improved from 42.73 to 72.38 (p < 0.001) and the Kujala score improved from 42 to 74.1 (p < 0.001), whereas in group B, the average KOOS improved from 39.22 to 56.84 (p < 0.001) and the Kujala score improved from 39.7 to 56.4 (p < 0.001).

CONCLUSION

Adding arthroscopic PD to OWHTO relieves anterior knee pain in patients with combined TF and PFOA and improves knee joint function and quality of life.

LEVEL OF EVIDENCE

Level I prospective randomised control clinical trial.

Patellar height is not modified after isolated open-wedge high tibial osteotomy without change in posterior tibial slope

INTRODUCTION

Open-wedge high tibial osteotomy (OWHTO) corrects coronal deformity and can impact sagittal parameters such as posterior tibial slope and patellar height. The aim of the present study was to analyze change in patellar height after medial OWHTO with respect to tibial and femoral-referenced indices.

MATERIAL AND METHOD

This single-center retrospective study included 129 patients undergoing isolated posteromedial OWHTO, without change in tibial slope, using patient-specific cutting-guides. Patellar height was assessed on Caton-Deschamps (CD), Insall-Salvati (IS) and Schröter indices. Posterior tibial slope and coronal femoral and tibial angles were also measured. X-rays were taken preoperatively and at 12 months, and analyzed by 2 independent observers.

RESULTS

OWHTO modified the global lower-limb alignment (Δ=6.3±0.95̊, p<0.0001) and the proximal tibial deformity (Δ=7±0.88̊, p<0.0001). Posterior tibial slope and tibial (CD and IS) and femoral (Schröter) patellar height indices were unchanged. Intra- and inter-observer reproducibility was excellent (ICC 0.79-0.91). There were no correlations between HKA or MPTA angles and change in patellar height.

CONCLUSION

The present clinical series showed that patellar height was unchanged by isolated posteromedial OWHTO without change in tibial slope, using patient-specific cutting-guides, with whichever femoral or tibial reference index. The Schröter patellar femoral height index was highly reliable and is independent of proximal tibial changes in assessing patellar height, and can thus be recommended in the follow-up of OWHTO.

LEVEL OF EVIDENCE

III; retrospective cohort study.

Effect of the amount of correction on posterior tibial slope and patellar height in open-wedge high tibial osteotomy

Objectives: To evaluate the effect of amount of correction on postoperative changes in PTS (posterior tibial slope), PH (patellar height), and clinical outcomes following biplanar OWHTO (open-wedge high tibial osteotomy). Method: This study included 79 knees (32 left and 47 right) of 79 patients (mean age 60.28 ± 4.2 years, 24 males, 55 females) with varus malalignment and symptomatic isolated medial joint osteoarthritis who underwent OWHTO. According to the amount of correction angles, all patients were divided into three groups: LCA (large correction angle) group (>14°), MCA (medium correction angle) group (10°-14°), and SCA (small correction angle) group (<10°). All patients were clinically assessed according to the Lysholm score, HSS (hospital for special surgery knee score), and KSS (knee society score) prior to and after surgery. For radiographic analysis, we measured the PTS, PH [ISI (Insall-Salvati index), and BPI (Blackburne-Peel index)]. The pre-post difference of PTS, ISI, and BPI was calculated by subtracting the post-OWHTO value to the pre-OWHTO value in three groups, respectively. The preoperative, postoperative, and difference of PTS, ISI, and BPI values were analyzed according to the correction angle. The mean follow-up period was 28.5 months (SD, 4.9; range 18-52 months). Results: Radiologically, PTS increased and PH decreased after surgery on the whole (p < .05). The relationship between amount of correction and slope increase is significant (p < .001). Furthermore, the pairwise difference between the LCA group and SCA group and MCA group is significant respectively (p < .05). In terms of PH, the LCA group yielded ISI and BPI that were significantly different from baseline for the SCA group and MCA group. In addition, the pairwise difference between the SCA group and LCA group in ISI and BPI is significant (p = .031). Clinically, significant improvements were observed in postoperative clinical scores of the Lysholm score, HSS, and KSS (p < .05). Seventy-four patients (93.67%) reported satisfaction with surgery. However, no correlation was found between changes in PTS and PH with postoperative knee score. No severe adverse complications were observed. Conclusions: The amount of correction angle is a significant factor affecting the PTS and PH in OWHTO. With increased correction angle, the likelihood of increasing the PTS and decreasing the PH increases. Special attention should be paid to keep PTS and PH unchanged in cases where large corrections are required. Otherwise, closing wedge osteotomy or other intraoperative effective measures are supposed to be adopted.

Increased contact area of flange and decreased wedge volume of osteotomy site by open wedge distal tibial tuberosity arc osteotomy compared to the conventional technique

PURPOSE

The purpose of this study was to evaluate the area of the osteotomy surface, including the flange and wedge volume, in open wedge high tibial osteotomy (OWHTO), distal tibial tuberosity osteotomy (DTO), and distal tibial tuberosity arc osteotomy (DTAO) using tibial sawbones. It was hypothesized that the area of the osteotomy surface, including the flange, in DTAO was larger than that in OWHTO and DTO and that the wedge volume in DTAO was smaller than that in OWHTO and DTO.

METHODS

Fifteen tibial sawbones were divided equally into three groups: OWHTO, DTO, and DTAO. The total area of the osteotomy surface in OWHTO, DTO, and DTAO was compared using image analysis software. The contact area of the flange and the wedge volume at wedge heights of 5, 10, and 15 mm were compared among osteotomy types. One-way repeated-measures analysis of variance was used to compare the total area of the osteotomy surface, the contact area of the flange, and the wedge volume at 5, 10, and 15 mm in OWHTO, DTO, and DTAO.

RESULTS

The total area of the osteotomy surface in DTO and DTAO was significantly larger than that in OWHTO (P < 0.05). The contact area of the flange in DTAO was significantly larger than that in OWHTO at each wedge height (P < 0.05). In addition, the contact area of the flange in DTAO was significantly larger than that in DTO at wedge heights of 5 and 15 mm (P < 0.05). The wedge volume in DTAO was significantly smaller than that in DTO at each wedge height (P < 0.05).

CONCLUSIONS

This study demonstrated that an increase in the flange contact area and a decrease in the wedge volume in the opening gap were found in DTAO compared to DTO. This would be an advantage for anteroposterior screw insertion from the flange to the distal tibial fragment and bone union at the osteotomy site.

Salvage of severe knee osteoarthritis: efficacy of tibial condylar valgus osteotomy versus open wedge high tibial osteotomy

INTRODUCTION

To compare the clinical outcomes and the radiographic features between tibial condylar valgus osteotomy (TCVO) and open wedge high tibial osteotomy (OWHTO). New insight into the indication criteria for TCVO was also clarified for achieving satisfactory results.

MATERIALS AND METHODS

Sixty-three knees with medial-compartment osteoarthritis were retrospectively studied. Thirty-four knees with subluxated lateral joint and depression of the medial tibial plateau underwent TCVO and the rest underwent OWHTO. Among the 63 knees included, 27 knees with a pre-operative femorotibial angle (FTA) ≥ 185° were defined as severe varus (subgroup S, 15 in S_TCVO group and 12 in S_HTO group). Lower limb alignment, intra-, and extra-articular congruency were evaluated according to the radiograph obtained before and 24 months after surgery. The visual analog scale (VAS) score and Hospital for Special Surgery (HSS) score were obtained to assess the clinical results. Opening angle and distance of the opening gap in each group were measured by intra-operative fluoroscopy.

RESULTS

During the 2-year follow-up period, the mean HSS score increased from 70.3 to 81.4 in HTO group and 65.9 to 87.3 in TCVO group (p < 0.05). The mean VAS score decreased from 5.9 to 2.6 and 6.0 to 2.1, respectively (p < 0.01). Pre-operative FTA was restored to 172.9° in HTO group and 171.3° in TCVO group, and percentage of mechanical axis (%MA) was improved to 59.7% and 61.2%, respectively. Joint line convergence angle (JLCA) was slightly restored and medial tibial plateau depression (MTPD) was relatively the same before and after OWHTO, while these parameters improved greatly (from 6.4° to 1.2° and - 8.0° to 5.9°, p < 0.01) in TCVO group. More undercorrected knees were observed in S_HTO group than S_TCVO group (58.3% and 13.3%, p < 0.05). Opening angle and distance of the opening gap were larger in TCVO group (19.1° and 14.0 mm) than those in OWHTO group (9.3° and 10.1 mm, p < 0.05).

CONCLUSION

Compared to OWHTO, TCVO had priority in treating advanced knee OA with intra-articular deformity. However, TCVO had a limited capacity to correct the varus angle. Besides, TCVO might be suitable for medial-compartment OA with a pre-operative FTA ≥ 185°.

The patellofemoral joint does not deteriorate clinically after open-wedge high tibial osteotomy

BACKGROUND

After high tibial osteotomy (HTO), the loading of the lateral compartment can be increased. Moreover, the change of patellar height may adversely affect the patellofemoral joint and functional outcomes.

HYPOTHESIS

We hypothesized that the cartilage of the lateral compartment and patellofemoral joint would worsen after open-wedge HTO and the overcorrection of HTO could worsen the cartilage state of the patellofemoral joint. We evaluated the cartilage status and clinical results after medial open-wedge HTO and the factors affecting the outcomes.

MATERIALS AND METHODS

From 2011 to 2018, 49 patients who had a mean age of 54.9 years and who underwent medial open-wedge HTO were selected. Plate removal was performed at a mean of 37.0 (range, 13-89) months after HTO, whereas diagnostic arthroscopy was performed during medial open-wedge HTO and plate removal. The cartilage status of each joint and the clinical results, including the Hospital for Special Surgery (HSS) score, Knee Society knee score (KS) and function score (FS), and patellar score, were compared. We evaluated the postoperative changes in the cartilage status and clinical scores. Additionally, we evaluated whether the postoperative correction degree could affect the clinical results.

RESULT

After medial open-wedge HTO, the patellar height decreased. There was no change in the cartilage at the patellar and femoral trochlear groove. The HSS score, KS, and FS improved, but the patellar score remained unchanged. In the overcorrection group, the cartilage status significantly deteriorated at the lateral tibia condyle as compared with that in the undercorrection group. Higher preoperative clinical scores were associated with less postoperative improvement.

DISCUSSION AND CONCLUSION

The outcomes in the patellofemoral joint, including the cartilage condition and clinical scores, did not change after open-wedge HTO, despite patellar infera. Additionally, they were not influenced by the correction degree. Higher preoperative clinical scores were associated with less postoperative improvement.

LEVEL OF EVIDENCE

IV; retrospective study.

Changes in the Contact Stress Distribution Pattern of the Patellofemoral Joint After Medial Open-Wedge High Tibial Osteotomy: An Evaluation Using Computed Tomography Osteoabsorptiometry

Background:

Medial open-wedge high tibial osteotomy (OWHTO) theoretically causes distalization and lateralization of the tibial tuberosity and the patella.

Purpose/Hypothesis:

The purpose of the study was to identify any changes in the stress distribution of subchondral bone density across the patellofemoral (PF) joint before and after OWHTO through the use of computed tomography (CT) osteoabsorptiometry. We hypothesized that OWHTO would alter the distribution of contact stress in the PF joint.

Study Design:

Case series; Level of evidence, 4.

Methods:

A total of 17 patients (17 knees) who underwent OWHTO were enrolled in this study between September 2013 and September 2015. All patients underwent radiologic examination preoperatively and at 1 year postoperatively, and the distribution patterns of subchondral bone density through the articular surface of the femoral trochlea and patella were assessed preoperatively and >1 year postoperatively using CT osteoabsorptiometry. The quantitative analysis of the obtained mapping data focused on location of the high-density area (HDA) through the articular surface of the PF joint. The percentage of HDA at each divided region of the articular surface of the femoral trochlea and the patella was calculated.

Results:

In the radiologic evaluation, the Blackburne-Peel ratio was significantly reduced (P < .001) after surgery, and the tilting angle of the patella was significantly decreased (P < .001). On CT evaluation, the percentage of HDA in the lateral notch and lateral trochlea of the femur and in the medial portion of the lateral facet of the patella increased significantly after OWHTO surgery (P ≤ .038).

Conclusion:

OWHTO significantly increased the stress distribution pattern of the lateral trochlea of the femur and the medial portion of the lateral facet of the patella. The procedure significantly lowered the patellar height and significantly decreased the patellar tilting angle after surgery.

[The influence of axial deformities and their correction on the development and progression of osteoarthritis]

Die Beachtung der Beinachse und die Möglichkeiten zur deren Korrektur stellen beim jungen Patienten mit Arthrose ein Grundpfeiler der Therapie dar. Die Kombination einer Gelenksverletzung und einer Achsdeviation führt unweigerlich, je nach Ausmaß und Komorbiditäten, schon nach wenigen Jahren zur fortschreitenden Gonarthrose. Neben der genauen Deformitätenanalyse zur Osteotomieplanung, gilt es, Normbereiche der entsprechenden Winkel zu kennen und eine Zielgröße zur Achskorrektur festzulegen. Aus dem Repertoire der verschiedenen kniegelenksnahen Osteotomien sind dann die Nebeneffekte in Bezug auf patellofemorales Maltracking, ligamentäres Balancing und die Beinlänge abzuschätzen. Gerade im Hinblick auf mögliche (und wahrscheinliche) Folgeoperationen beim jungen Patienten müssen neue knöcherne Deformitäten oder ligamentäre Insuffizienzen, welche potenziell bei Überkorrektur entstehen, unbedingt vermieden werden.

Proximal tibial osteotomy for genu varum: Radiological evaluation of deformity correction with a plate vs external fixator

BACKGROUND

High tibial osteotomy (HTO) is a well-known procedure for the correction of knee varus. The purpose of this study was to compare the radiological results and accuracy of deformity correction performed using two different techniques: acute opening wedge correction using a plate and gradual correction with a monolateral external fixator.

AIM

To compare of the radiological results of two different techniques: acute opening wedge correction (a plate and screw) and gradual correction (external fixator).

METHODS

A total of 43 patients with plates and 36 patients with external fixators were included. All patients had moderate uniplanar varus deformities. We measured radiographic parameters, including the mechanical axis deviation (MAD), medial proximal tibial angle (MPTA), Caton-Deschamps Index (CDI), posterior proximal tibial angle, and joint line obliquity angle (JLOA). The accuracy of MAD correction was calculated based on a correction goal of neutral or overcorrection for medial compartment arthritis.

RESULTS

Demographics including age, body mass index, sex, and preoperative deformities were similar between the groups. The MAD significantly improved from 23.6 mm medial to the midline (SD = 8.2 mm) to 6.9 mm lateral to the midline (SD = 5.4 mm) (P < 0.001). The accuracy of MAD correction did not differ between the groups and was 96.1% (SD = 8.1%) in the plate group and 98.2% (SD = 5.2%) in the external fixator group (P = 0.18). The MPTA significantly improved from 83.9° (SD = 2.9°) to 90.9° (SD = 3.3°) (P < 0.001), and the change was similar between the groups. Differences were noted in patella height, with a CDI change of -19.2% (SD = 13.7%) and 3.1% (SD = 8.0%) for the plate and external fixator groups, respectively (P < 0.001). The change in JLOA was 1.6 degrees (SD = 1.1 degrees) and 0.9 degrees (SD = 0.9 degrees) for the plate and external fixator groups, respectively (P = 0.04).

CONCLUSION

Reliable correction of moderate varus alignment was achieved with both the acute opening wedge technique with a plate and the gradual monolateral external fixator technique. The patellar height decreased with the open wedge plate technique. Joint line obliquity decreased to a greater degree with the open wedge plate technique, perhaps as a result of medial collateral ligament release. The appropriate technique should be selected based on surgeon and patient preferences; however, external fixation may be a better choice when the preservation of patellar height is deemed important.

Rotational Changes in the Tibia After High Tibial Valgus Osteotomy: A Comparative Study of Lateral Closing Versus Medial Opening Wedge Osteotomy

BACKGROUND

After high tibial valgus osteotomy (HTO), rotational changes in the tibia may occur, which can affect the biomechanics of the patellofemoral joint and may lead to anterior knee pain.

PURPOSE

To compare the rotational changes in the tibia between closing wedge HTO (CWHTO) and opening wedge HTO (OWHTO).

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Among the patients who underwent HTO between May 2012 and August 2015, 53 (28 CWHTO and 25 OWHTO) who had computed tomography scans before and at 1 year after the HTO were included. The following parameters were compared between CWHTO and OWHTO: (1) tibial torsion angle, (2) knee rotation angle, and (3) tibial tuberosity-trochlear groove (TT-TG) distance. During the last follow-up, patients were asked to rate their anterior knee pain when climbing the stairs, using the visual analog scale.

RESULTS

The tibial torsion angle significantly decreased (internal rotation of the distal fragment) after CWHTO (mean ± SD, -2.1°± 4.1°; P = .019) and OWHTO (-1.8°± 3.3°; P = .029). The knee rotation angle significantly decreased (external rotation of the proximal fragment) after OWHTO (-1.8°± 3.4°; P = .039) but was not changed after CWHTO (0.1°± 3.1°; P = .859). The mean TT-TG distance significantly decreased after CWHTO (-3.1 ± 3.0 mm; P < .001) but increased after OWHTO (2.0 ± 4.3 mm; P = .012). At the final follow-up (minimum, 4 years), the visual analog scale pain score during stair climbing was significantly higher after OWHTO than after CWHTO (3.1 ± 1.4 vs 2.2 ± 1.3, P = .024).

CONCLUSION

Internal rotation of the distal fragment occurred after both CWHTO and OWHTO. However, external rotation of the proximal fragment and increased TT-TG distance occurred after OWHTO. Because such rotational changes could affect anterior knee pain, further studies are warranted to investigate the definite relationship between tibial rotational changes and anterior knee pain after HTO.

Assessment of Open-Wedge High Tibial Osteotomy Plus Tibial Tubercle Osteotomy: A Novel Approach for Genu Varum Treatment

Background

Lower extremity genu varum is a common deformity leading to imbalanced weight distribution on the knee joint and eventually significant disabilities due to medial compartment joint osteoarthritis. This study was aimed to assess the efficacy of a novel technique of high tibial open wedge osteotomy plus tubercle osteotomy in a follow-up study.

Materials and Methods

This is a prospective census cross-sectional study conducted on 146 patients with the history of genu varus undergone high tibial open-wedge osteotomy and tubercle osteotomy since 2011. The study population was followed within 6 months regarding tibial slope angle and medial proximal tibial angle alterations and operation-related complications, including venous phlebitis, nerve, and arterial injury, deep and superficial infection, mal-, non- and delayed-union.

Results

146 patients with the mean age of 25.66 ± 4.23 years, and predominance of male gender (60.3%) were evaluated. Mean of tibia slope and MPTA before the surgical procedure was 9.38 ± 0.85 and 79.45 ± 2.11 that turned to 7.10 ± 0.84 and 89.74 ± 1.52 postoperatively, respectively (P < 0.001). Arterial and peroneal nerve injury was not detected in any of the cases. Deep-vein phlebitis, superficial infection, and delayed-union, malunion, and nonunion were presented in 2.05%, 1.36%, and 2.05%, respectively.

Conclusion

Outcomes of this study showed significant improvement in the tibia slope angle and MPTA postoperatively. Surgical-associated complications were negligible and rehabilitated by performing appropriate medical/surgical approaches. Considering the number of assessed population, HTO plus tubercle osteotomy seems an acceptable approach for genu varum treatment.

Functional Outcome of High Tibial Osteotomy in Patients with Medial Compartment Osteoarthritis Using Dynamic Axial Fixator -a prospective study

INTRODUCTION

Medial Compartment Osteoarthritis of the knee is becoming a widespread problem. The surgical options include high tibial osteotomy, unicompartmental knee replacement, and total knee replacement. Replacement surgeries are not advised in the younger age group, so in these patients, high tibial osteotomy is the only option. In this study, we have assessed the functional and radiological outcomes of high tibial osteotomy done by hemicallostasis method.

METHOD

We report the outcome of 30 patients (30 knees) who underwent hemicallostasis with a dynamic external fixator for medial compartment osteoarthritis of the knee. The radiological assessment was done with the help of Hip Knee Ankle angle. The functional scoring was done via Oxford knee score, IKDC, KOOS, and WOMAC score.

RESULTS

At a mean follow up of 35 months, the preoperatively mean HKA angle was 172 ± 30. The mean HKA angle postoperatively was 184 ± 10. Appropriate correction of the HKA angle was achieved in 24 of 30 patients (80%). Whereas, there was under correction in 3 patients (10%) and overcorrection in 3 (10%) patients. All the functional scores showed significant improvement in the postoperative scores. There was a positive correlation between the HKA angle and oxford, IKDC, KOOS, and WOMAC Score. Complications like superficial pin tract infection were seen in 3 (10%) patients, deep infection in 1 (3%), and early union of osteotomy in 1 (3%) patient leading to revision of the osteotomy. .

CONCLUSION

HTO is effective in improving pain, function, activity of daily living, and quality of life in patients suffering from medial compartment Osteoarthritis of the knee. Hip Knee Ankle Angle is an important parameter to restore for better functional outcomes. The Advantage of using a dynamic axial fixator is the precision in achieving calculated correction without any implant in the bone once the correction is achieved along with good healing rates.

An Acute Oblique Osteotomy and Suture Ligation Procedure to Shorten the Fibula in Lateral Closing-Wedge High Tibial Osteotomy

The purpose of this description is to report an "acute oblique osteotomy and ligation" (AOOL) procedure to shorten the fibula in high tibial osteotomy (HTO). A 4-cm longitudinal skin incision is made at the lateral aspect of the leg. After the central portion of the fibula is circumferentially isolated from all the periosteal tissues, a simple osteotomy is performed at the mid-portion of the fibular diaphysis in the quasi-frontal plane, which is inclined by 25 to 30° to the long axis of the fibula. Two thin holes are created beside the osteotomy line on the lateral surface of the fibula. A polyester thread is passed through the 2 holes. After the HTO is completed, the surgeon easily reduces the displaced fibular ends using this thread. This thread is securely tied to keep the contact between the 2 osteotomized surfaces. The AOOL procedure is technically easy and safely performed. We believe that the AOOL procedure is clinically useful to shorten the fibular shaft in HTO.

Changes in lower limb alignment and their effect on the functional outcome after treatment of varus degenerative OA knee by hemicallotasis using modular dynamic HTO fixator

OBJECTIVE

High tibial osteotomy (HTO) is an established procedure to treat medial compartmental osteoarthritis (OA) knee associated with varus deformity. It is well documented that precise correction of deformity and maintenance of correction achieved is important to ensure long term good results. This study was undertaken to record changes in radiological parameters and its effect on the functional outcomes in first two years following HTO done for varus degenerative OA kneeby hemicallotasis technique using HTO fixator.

METHODS

31 patients meeting our inclusion-exclusion criteria who underwent HTO by hemicallotasis method using self-adjusting unilateral HTO fixator were included in the study. Their femoro tibial angle (FTA), mechanical axis %, Insall- Salvati ratio, proximal tibial antero-posterior slope and knee injury and osteoarthritis outcome Score (KOOS) were recorded preoperatively, postoperatively at the time of removal of fixator, at 1 year and at 2 years.

RESULTS

The FTA and mechanical axis significantly improved from a mean of 183.12⁰ and -3.26% respectively preoperatively to 173.38⁰ and 61.81% at the time of removal of fixator but subsequently showed significant deterioration to 176.06⁰ and 57.96% at 1 year and further insignificant deterioration to 176.16⁰ and 57.74 at 2 years. The KOOS improved from mean 56.61 preoperatively to 70.48 at the time of fixator removal and further improved significantly to 85.68 at 1 year but significantly deteriorated to 84.54 at 2 years. The Insall-Salvati ratio, tibial slope showed no significant change throughout the study. Conclusion: Though desired alignment can be achieved by using the fixator, we found a significant deterioration in achieved radiological parameters after removal of fixator adversely affecting the functional outcome which is a matter of concern.

Distal tuberosity osteotomy in open-wedge high tibial osteotomy does not exacerbate patellofemoral osteoarthritis on arthroscopic evaluation

PURPOSE

The purpose of the present study was to use arthroscopy to evaluate the effect of distal tuberosity osteotomy (DTO) in open-wedge high tibial osteotomy (OW-HTO) on patellofemoral (PF) cartilage degradation.

METHODS

Between 2012 and 2017, 46 knees underwent DTO in OW-HTO, and 65 knees underwent conventional OW-HTO (cOW-HTO). To assess changes in patellar height, the Blackburne-Peel (BP) ratio and the Caton-Deschamps (CD) index were measured. Arthroscopic evaluation on the PF joint was performed at the initial osteotomy and at the second-look procedure 1 year later. Statistical analyses were performed to compare difference between the DTO and the cOW-HTO group.

RESULTS

In the cOW-HTO group, the mean BP ratio and CD index decreased significantly from 0.81 and 0.89 preoperatively, respectively, to 0.69 and 0.76 postoperatively, respectively (p < 0.001). In contrast, the DTO group maintained a consistent patellar height; the mean BP ratio and CD index were 0.77 and 0.83 preoperatively, respectively, and 0.73 and 0.80 postoperatively, respectively. Upon arthroscopic evaluation, 39 of 46 patients (84.8%) in the DTO group showed no progression of PF cartilage degradation at the second look; indeed, five of 46 patients (10.9%) even demonstrated improvement. In contrast, 21 of 65 patients (32.3%) in the cOW-HTO group exhibited increased PF cartilage degradation. There was a significant difference in progression of PF cartilage degradation between DTO and cOW-HTO (p < 0.001).

CONCLUSION

DTO in OW-HTO maintained the preoperative patellar height, which could help prevent progression of cartilage degeneration in the PF joint after surgery. In respect of the biplanar osteotomy direction in OW-HTO, the DTO, rather than cOWHTO, is the preferred technique for the treatment of varus knee osteoarthritis to avoid progression of PF cartilage degradation.

LEVEL OF EVIDENCE

III.

A novel device for greater precision and safety in open-wedge high tibial osteotomy: cadaveric study

INTRODUCTION

The complications of the open-wedge osteotomy technique (slope, hypo- and hypercorrection and fractures) are related to difficulties in the control of the open-wedge angle during surgery.

MATERIALS AND METHODS

In this cadaveric study, we evaluated the safety and precision of a novel system, the Realignment High Control System (RHC), in the correction of knee mechanical axis and slope. The RHC has a fixation plate coupled to a dynamic device that opens the osteotomy continuously, allowing plate fixation before osteotomy wedge opening.

RESULTS

All procedures were easily performed, with no fractures. The openings equaled the indicated by the navigation system for 7.5° and 10°, and for 5°, there was a statistically, although not clinically significant, difference of 0.6°. The slope shown by the RHC setting and in the navigation system was significantly different for the 10° setting only, with a mean difference of 0.563°.

CONCLUSIONS

RHC facilitates the surgical technique of high tibial osteotomy, with gradual wedge opening, precise correction of the mechanical axis, and appropriate control of the tibial slope, even with larger openings.

ACL degeneration after an excessive increase in the medial proximal tibial angle with medial open wedge high tibial osteotomy

PURPOSE

This study examined the influence of the mechanical medial proximal tibial angle (MPTA) on anterior cruciate ligament (ACL) degeneration following open wedge high tibial osteotomy (OWHTO). It was hypothesised that an excessive increase in MPTA would be associated with ACL degeneration following OWHTO.

METHODS

Seventy-four knees treated with OWHTO were retrospectively examined. Arthroscopic ACL grading [0 (intact) to 4 (complete rupture)], anterior tibial translation (ATT) test at the time of OWHTO with the index arthroscopy and at plate removal with the second-look arthroscopy, clinical assessments using the Knee Society Score (KSS), and radiographic evaluations of MPTA were performed. The relationship between MPTA and the ACL condition was analysed using Spearman's correlation.

RESULTS

The time from the index arthroscopy to the second-look arthroscopy was 15.0 ± 4.4 months; the total follow-up was 31.0 ± 6.5 months. ACL grade significantly increased from 0.6 ± 0.8 (index arthroscopy) to 1.1 ± 1.2 (second-look arthroscopy) (p < 0.0018). ATT on the operated side significantly decreased from 7.1 ± 2.6 mm preoperatively to 5.3 ± 2.3 mm at the time of plate removal (p < 0.001). No significant difference was observed in KSS for ACL grades in the steady and progression groups. Changes in MPTA from the preoperative to postoperative period were significantly higher in the progression group (p = 0.0155). Changes in ACL grades were significantly correlated with preoperative MPTA and changes in MPTA (r = - 0.365 and 0.343, respectively; p < 0.01).

CONCLUSIONS

Excessively increased MPTA led to ACL degeneration following OWHTO. ACL degeneration was not associated with short-term clinical outcomes. Excessive correction of MPTA should be avoided to prevent ACL degeneration following OWHTO.

LEVEL OF EVIDENCE

Therapeutic case series, Level IV.

Comparison of radiological features of high tibial osteotomy and tibial condylar valgus osteotomy

Background

The purpose of this study was to compare radiological features between high tibial osteotomy (HTO) and tibial condylar valgus osteotomy (TCVO), in order to define the radiological indication criteria for TCVO.

Methods

Thirty-two cases involving 35 knees that had undergone HTO and the same number that had undergone TCVO for knee osteoarthritis were retrospectively evaluated. Characteristics of both groups did not differ significantly. Lower limb alignment, bone morphology, joint congruity, and joint instability were measured in standing full-length leg and knee radiographs obtained before and after surgery.

Results

Radiological features in the TCVO group included greater frequencies of advanced knee OA grade, varus lower limb malalignment, depression of the medial tibial plateau, and varus-valgus joint instability compared to the HTO group before surgery. However, tibial morphology, alignment of the lower limb, and joint instability improved to comparable levels after surgery in both groups.

Conclusions

TCVO appears preferable in cases with advanced knee OA, destroyed or inclined medial tibial plateau, widened and subluxated lateral joint, and high varus-valgus joint instability.

Surgical interventions for symptomatic mild to moderate knee osteoarthritis

BACKGROUND

Osteoarthritis affecting the knee is common and represents a continuum of disease from early cartilage thinning to full-thickness cartilage loss, bony erosion, and deformity. Many studies do not stratify their results based on the severity of the disease at baseline or recruitment.

OBJECTIVES

To assess the benefits and harms of surgical intervention for the management of symptomatic mild to moderate knee osteoarthritis defined as knee pain and radiographic evidence of non-end stage osteoarthritis (Kellgren-Lawrence grade 1, 2, 3 or equivalent on MRI/arthroscopy). Outcomes of interest included pain, function, radiographic progression, quality of life, short-term serious adverse events, re-operation rates and withdrawals due to adverse events.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase up to May 2018. We also conducted searches of ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform for ongoing trials. Authors of trials were contacted if some but not all their participants appeared to fit our inclusion criteria.

SELECTION CRITERIA

We included randomised controlled trials that compared surgery to non-surgical interventions (including sham and placebo control groups, exercise or physiotherapy, and analgesic or other medication), injectable therapies, and trials that compared one type of surgical intervention to another surgical intervention in people with symptomatic mild to moderate knee osteoarthritis.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials and extracted data using standardised forms. We analysed the quality of evidence using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach.

MAIN RESULTS

A total of five studies involving 566 participants were identified as eligible for this review. Single studies compared arthroscopic partial meniscectomy to physical therapy (320 participants), arthroscopic surgery (debridement ± synovectomy ± chondroplasty) to closed needle joint lavage with saline (32 participants) and high tibial osteotomy surgery to knee joint distraction surgery (62 participants). Two studies (152 participants) compared arthroscopic surgery (washout ± debridement; debridement) to a hyaluronic acid injection. Only one study was at low risk of selection bias, and due to the difficulty of blinding participants to their treatment, all studies were at risk of performance and detection bias.Reporting of results in this summary has been restricted to the primary comparison: surgical intervention versus non-surgical intervention.A single study, included 320 participants with symptoms consistent with meniscal tear. All subjects had the meniscal tear confirmed on knee MRI and radiographic evidence of mild to moderate osteoarthritis (osteophytes, cartilage defect or joint space narrowing). Patients with severe osteoarthritis (KL grade 4) were excluded. The study compared arthroscopic partial meniscectomy and physical therapy to physical therapy alone (a six-week individualised progressive home exercise program). This study was at low risk of selection bias and outcome reporting biases, but was susceptible to performance and detection biases. A high rate of cross-over (30.2%) occurred from the physical therapy group to the arthroscopic group.Low-quality evidence suggests there may be little difference in pain and function at 12 months follow-up in people who have arthroscopic partial meniscectomy and those who have physical therapy. Evidence was downgraded to low quality due to risk of bias and imprecision.Mean pain was 19.3 points on a 0 to 100 point KOOS pain scale with physical therapy at 12 months follow-up and was 0.2 points better with surgery (95% confidence interval (CI) 4.05 better to 3.65 points worse with surgery, an absolute improvement of 0.2% (95% CI 4% better to 4% worse) and relative improvement 0.4% (95% CI 9% better to 8% worse) (low quality evidence). Mean function was 14.5 on a 0 to 100 point KOOS function scale with physical therapy at 12 months follow-up and 0.8 points better with surgery (95% CI 4.3 better to 2.7 worse); 0.8% absolute improvement (95% CI 4% better to 3% worse) and 2.1% relative improvement (95% CI 11% better to 7% worse) (low quality evidence).Radiographic structural osteoarthritis progression and quality of life outcomes were not reported.Due to very low quality evidence, we are uncertain if surgery is associated with an increased risk of serious adverse events, incidence of total knee replacement or withdrawal rates. Evidence was downgraded twice due to very low event rates, and once for risk of bias.At 12 months, the surgery group had a total of three serious adverse events including fatal pulmonary embolism, myocardial infarction and hypoxaemia. The physical therapy alone group had two serious adverse events including sudden death and stroke (Peto OR 1.58, 95% CI 0.27 to 9.21); 1% more events with surgery (95% CI 2% less to 3% more) and 58% relative change (95% CI 73% less to 821% more). One participant in each group withdrew due to adverse events.Two of 164 participants (1.2%) in the physical therapy group and three of 156 in the surgery group underwent conversion to total knee replacement within 12 months (Peto OR 1.76, 95% CI 0.43 to 7.13); 1% more events with surgery (95% CI 2% less to 5% more); 76% relative change (95% CI 57% less to 613% more).

AUTHORS' CONCLUSIONS

The review found no placebo-or sham-controlled trials of surgery in participants with symptomatic mild to moderate knee osteoarthritis. There was low quality evidence that there may be no evidence of a difference between arthroscopic partial meniscectomy surgery and a home exercise program for the treatment of this condition. Similarly, low-quality evidence from a few small trials indicates there may not be any benefit of arthroscopic surgery over other non-surgical treatments including saline irrigation and hyaluronic acid injection, or one type of surgery over another. We are uncertain of the risk of adverse events or of progressing to total knee replacement due to very small event rates. Thus, there is uncertainty around the current evidence to support or oppose the use of surgery in mild to moderate knee osteoarthritis. As no benefit has been demonstrated from the low quality trials included in this review, it is possible that future higher quality trials for these surgical interventions may not contradict these results.

Radiographic changes and clinical outcomes after open and closed wedge high tibial osteotomy: a systematic review and meta-analysis

BACKGROUND

The purpose of this meta-analysis is to examine changes in radiological variables and clinical outcomes between open and closed wedge high tibial osteotomy (OWHTO and CWHTO, respectively), which have ongoing controversial issues in numerous quantitative clinical studies.

METHODS

PubMed, Embase, and the Cochrane Library were systematically searched for suitable controlled trials between Jan 1, 1999, and Feb 2, 2018. The inclusion criteria included studies written in English, studies with a level of evidence of I-IV, and studies presenting comparisons between OWHTO and CWHTO. The main clinical and radiographic results were extracted and pooled using Stata 12.0.

RESULTS

After searching for and screening trials, 28 trials involving 2840 knees were eligible for the meta-analysis. After OWHTO or CWHTO, clinical scores, including the American Knee Society Score, Hospital for Special Surgery Knee Score, Lysholm score, and Visual Analog Scale pain score, improved (p < 0.05), but the range of motion was unchanged (p > 0.05). The anatomical femorotibial angle (SMD 0.04, 95% CI - 0.66 to 0.74) and hip-knee-ankle angle (SMD 0.11, 95% CI - 0.11 to 0.33) data suggested that the OWHTO and CWHTO groups were similar in function of correction. Posterior tibial slope increased (SMD - 0.71, 95% CI - 1.04 to - 0.37) after OWHTO but decreased (SMD 0.72, 95% CI 0.35 to 1.08) after CWHTO. OWHTO decreased patellar height (p < 0.05), while patellar height did not change significantly after CWHTO (p > 0.05).

CONCLUSION

This meta-analysis indicates that compared with CWHTO, OWHTO increases the posterior slope, decreases the patellar height, and provides a similar accuracy of correction; however, CWHTO leads to a decreased posterior slope and an unchanged patellar height. Therefore, programs should be personalized and customized for the specific situation of each patient.

High Tibial Osteotomy and Anterior Cruciate Ligament Reconstruction/Revision

High tibial osteotomy (HTO) may be performed in association with anterior cruciate ligament (ACL) reconstruction/revision in patients with medial osteoarthritis, varus malalignment, and anterior instability. Furthermore, it may be performed in patients with varus alignment and increased posterior tibial slope (exceeding 12°), because it is related to an increased risk for ACL failure. There are different techniques to perform HTO, and consequently, a concomitant HTO and ACL reconstruction/revision. This article describes the indication, surgical techniques, and outcomes of concomitant HTO and ACL reconstruction/revision.

Short-term functional outcomes of computer assisted navigated high tibial osteotomy

Purpose

High tibial osteotomy (HTO) is a surgical procedure performed on patients with knee osteoarthritis (OA). Computer assisted navigated high tibial osteotomy (CAN-HTO) may result in improved outcomes for patients undergoing this procedure.

Methods

Retrospective study involving patients undergoing CAN-HTO.

Results

Surveyed thirty-three patients. Average follow-up: 2.3 years. 97% patients reported they would have this procedure performed again, if indicated. Re-operation rate: 6.1% and complication rate: 12.1%. Patients had decreased KOOS for symptoms when compared to non-navigation based HTO (p = 0.000).

Conclusion

There may be merit with the use of CAN-HTO, with demonstrated patient-reported benefits at 2-year follow-up.

Advances in modern osteotomies around the knee : Report on the Association of Sports Traumatology, Arthroscopy, Orthopaedic surgery, Rehabilitation (ASTAOR) Moscow International Osteotomy Congress 2017

Corrective lower limb osteotomies are innovative and efficient therapeutic procedures for restoring axial alignment and managing unicompartmental knee osteoarthritis. This review presents critical insights into the up-dated clinical knowledge on osteotomies for complex posttraumatic or congenital lower limb deformities with a focus on high tibial osteotomies, including a comprehensive overview of basic principles of osteotomy planning, biomechanical considerations of different implants for osteotomies and insights in specific bone deformity correction techniques. Emphasis is placed on complex cases of lower limb osteotomies associated with ligament and multiaxial instability including pediatric cases, computer-assisted navigation, external fixation for long bone deformity correction and return to sport after such osteotomies. Altogether, these advances in the experimental and clinical knowledge of complex lower limb osteotomies allow generating improved, adapted therapeutic regimens to treat congenital and acquired lower limb deformities.

Prevalence of excessive lateral pressure syndrome in varus osteoarthritic candidates for high tibial osteotomy

BACKGROUND

This study aimed to determine the prevalence of excessive lateral pressure syndrome (ELPS) in potential candidates for high tibial osteotomy (HTO) using single-photon emission computed tomography-computed tomography (SPECT-CT). We also sought to identify risk factors related to the presence of ELPS.

METHODS

This retrospective study included 150 patients (216 knees) who were candidates for HTO from an initial screening of 3579 patients (7158 knees). There were 183 female and 33 male knees with a mean age of 58 years. The presence of ELPS was defined as a grade 3 uptake on the SPECT-CT at the lateral PF joint. To determine the risk factors related to the ELPS, multivariate regression analysis was performed with independent demographic and radiographic variables.

RESULTS

Increased uptake on the lateral side of the PF joints was detected in 120 knees (56% of total subjects). Of these, 34 (16%) knees presented with a grade 3 uptake, which indicated the presence of ELPS. No single risk factor had significant associations with the presence of ELPS.

CONCLUSIONS

A considerable number of the knees that were candidates for HTO had ELPS. Nonetheless, we did not find any risk factor related to the presence of ELPS. These results suggest that surgeons should be cautious when diagnosing concomitant ELPS despite acceptable radiographic findings from patellofemoral joints when performing HTO.

More accurate correction can be obtained using a three-dimensional printed model in open-wedge high tibial osteotomy

PURPOSE

The purpose of this study was to compare the accuracy of the preoperative planning method using a three-dimensional (3D) printed model with that of a method using picture archiving and communication system (PACS) images in high tibial osteotomy (HTO).

METHODS

Patients who underwent HTO using a 3D printed model (20 patients) and a method based on PACS images (20 patients) from 2012 to 2016 were compared. After obtaining the correction angle, in the 3D printed method, the wedge-shaped 3D printed model was designed. The PACS method used preoperative radiographs. The accuracy of HTO for each method was compared using radiographs obtained at the first postoperative year. The preoperative and postoperative posterior tibial slope angles were also compared.

RESULTS

The weight-bearing line was corrected 21.2 ± 11.8% from preoperatively to 61.6 ± 3.3% postoperatively in the 3D group and from 19.4 ± 12.3% to 61.3 ± 8.1% in the PACS group. The mean absolute difference with the target point was lower in the 3D group (2.3 ± 2.5) than in the PACS group (6.2 ± 5.1; p = 0.005). The number of patients in an acceptable range was higher in the 3D group than in the PACS group. The posterior tibial slope angle was not significantly different in the 3D group (8.6°-8.9°), but was significantly different in the PACS group (9.9°-10.5°, p = 0.042).

CONCLUSIONS

In open-wedge HTO, a more accurate correction for successful results could be obtained using the 3D printed model.

LEVEL OF EVIDENCE

IV.