Open wedge tibial osteotomy with acrylic bone cement as bone substitute

Gap Volume Based on CT Measurement Is a Strong Risk Factor for Delayed Gap Healing After Open-wedge High Tibial Osteotomy

PURPOSE

To identify factors that affect delayed gap healing after open-wedge high tibial osteotomy (OWHTO), and to determine whether large gap volume is a predictor of delayed gap healing.

METHODS

This retrospective study analyzed biplane OWHTO performed between 2019 and 2023 for knee osteoarthritis or osteonecrosis. The minimum follow-up was 1 year. Delayed gap healing was defined as when the medial half of the osteotomy gap area had not reached the consolidation phase by 6 months after surgery based on anteroposterior knee radiographs. Gap volume was calculated from computed tomography images. Logistic regression was performed using body height, smoking, correction angle, hinge fracture, flange thickness, and gap volume. A gap volume cutoff value for delayed gap healing was determined with receiver operating characteristic curve analysis. Gap volume was predicted with multiple linear regression.

RESULTS

There were 80 knees in 71 patients (36 men and 44 women). The mean gap volume was 7.6 cm3. Gap healing rates at 3, 6, 9, and 12 months after surgery were 26%, 65%, 89%, and 100%, respectively. There were 25 knees with delayed gap healing. Male sex was not a significant risk factor when adjusted for body height. Multivariate logistic regression revealed that only larger gap volume was a significant risk factor (odds ratio, 1.45; P = .006). The gap volume cutoff value was 7.6 cm3, with an area under the curve of 0.74. Tall body height and a large correction angle (both P < .001) were associated with a significantly larger gap volume (R2 = 0.73).

CONCLUSIONS

Large gap volume is the most important risk factor for delayed gap healing after OWHTO. Gap volume can be predicted based on body height and correction angle. When OWHTO with substantial correction is planned for a tall man, surgeons should be aware of possibly delayed gap healing.

'One millimetre equals one degree' is a major source of inaccuracy in planning osteotomies around the knee for metaphyseal deformities compared to the digital planning

PURPOSE

The objective of this study was to compare the accuracy of virtually performed osteotomies around the knee. The comparison was made between the Miniaci method (method 1), considered the gold standard planning, with the widely held dogma that one degree of correction required equates to one millimetre of opening/closing (method 2).

METHODS

This retrospective cross-sectional study was conducted between December 2018 and September 2022 in patients aged at least 15 years with metaphyseal knee deformity. Osteotomy planning was performed in methods 1 and 2 utilising calibrated long-leg alignment X-rays in the frontal plane. In both methods, the desired correction was defined by the Fujisawa point. The error % in measurement (ratio method 1/method 2) and the difference in millimetres (method 1 - method 2) between the two methods were analysed.

RESULTS

A total of 107 osteotomies with 27 (25.2%) distal femoral osteotomies, 54 (50.5%) proximal tibial osteotomies and 26 (24.3%) double-level osteotomies were performed virtually with a mean hip-knee-ankle angle of 176.4 ± 6.6. In distal femur osteotomy, the mean error % between methods 1 and 2 was 38.9 ± 16.7% and 22.4 ± 16.8% for the opening and closing groups, respectively. In proximal tibial osteotomies, the mean error % was 22.7 ± 15.6% and 9 ± 10.8% for the opening and closing groups, respectively. In double-level osteotomy, the mean error % of femur-based corrections was 34.9 ± 19% and 19.5 ± 21% for the opening and closing groups, respectively, and the mean error of the tibial-based corrections was 26.4 ± 12.1% for the opening group and 10.8 ± 10% for the closing group, respectively.

CONCLUSION

Planning one millimeter per degree of desired correction for osteotomies around the knee in metaphyseal deformities is a major source of error when compared with digital planning using the Miniaci method. This was seen most frequently with osteotomies of the distal femur and all opening wedge osteotomies.

LEVEL OF EVIDENCE

Level Ⅲ, retrospective cross-sectional study.

Bone Healing and Clinical Outcome Following Medial Opening-wedge High Tibial Osteotomy Using Wedge-Shaped Cancellous Allograft

OBJECTIVE

Medial opening-wedge high tibial osteotomy (MOWHTO) is considered to be an effective treatment for symptomatic knee osteoarthritis (KOA) of isolated the medial compartment with varus alignment of the lower extremity. However, the choice of material to fill the void remains controversial. This study aims to evaluate the bone union of the osteotomy gap using a novel wedge-shaped cancellous allograft after MOWHTO and its effect on clinical outcomes.

METHODS

All patients who underwent MOWHTO using a novel wedge-shaped cancellous allograft combined with TomoFix locking compression plate (LCP) fixation between January 2016 and July 2020 were enrolled. The radiographic parameters including hip-knee-ankle angle (HKAA), medial proximal tibial angle (MPTA), femorotibial angle (FTA) and posterior tibial slope angle (PTSA) were measured between pre-operative and post-operative radiographs. Knee Society score (KSS) and range of motion (ROM) were assessed preoperatively and at last follow-up. Patients included in this study were divided into two groups according to the correction angle: small correction group (< 10°; SC group) and large correction group (≥ 10°; LC group). The modified Radiographic Union score for tibial fractures (mRUST) was used to assess the difference in bone healing between the two groups at 1, 3, 6, and 12 months postoperatively and at the final follow-up. A paired student's t test was conducted for comparison of differences of the relevant data pre-operatively and post-operatively.

RESULTS

A total of 82 patients (88 knees) were included in this study. The HKAA, MPTA, FTA and PTSA increased from -6.4° ± 3.0°, 85.1° ± 2.6°, 180.1° ± 3.2° and 7.7° ± 4.4° preoperatively to 1.2° ± 4.3° (p < 0.001), 94.4° ± 3.3° (p < 0.001), 171.0° ± 2.8° and 11.8° ± 5.8° (p < 0.001) immediately postoperatively, respectively. However, no significant statistic difference was found in above-mentioned parameters at last follow-up compared to immediate postoperative data (p > 0.05). All patients in this study achieved good bone healing at the final follow-up and no significant differences in mRUST scores were seen between the SC group and LC group. The KSS-Knee score and KSS-Function score improved significantly from 55.4 ± 3.7 and 63.3 ± 4.6 preoperatively to 86.4 ± 2.8 (p < 0.001) and 89.6 ± 2.9 (p < 0.001) at last follow-up, respectively. Nevertheless, there was no significant difference in ROM between pre-operation and last follow-up (p > 0.05).

CONCLUSION

For MOWHTO, the wedge-shaped cancellous allograft was a reliable choice for providing good bone healing and clinical outcomes.

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.

Assessment of joint line obliquity and its related frontal deformity using long-standing radiographs

Purpose

To investigate how radiographic techniques and osteoarthritis grade influence measurements of knee joint line obliquity (KJLO) and KJLO-related frontal deformity, and to propose preferable KJLO measurement methods.

Methods

Forty patients with symptomatic medial knee osteoarthritis indicated for high tibial osteotomy were assessed. Measurements were compared between single-leg and double-leg standing radiographs for KJLO measurement methods including joint line orientation angle by femoral condyles (JLOAF), joint line orientation angle by middle knee joint space (JLOAM), joint line orientation angle by tibial plateau (JLOAT), Mikulicz joint line angle (MJLA) and medial proximal tibial angle (MPTA), as well as KJLO-related frontal deformity parameters including joint line convergence angle (JLCA), knee ankle joint angle (KAJA) and hip-knee-ankle angle (HKA). Influences of bipedal distance in double-leg standing and osteoarthritis grade on the above measurements were analysed. Measurement reliability was evaluated by intraclass correlation coefficient.

Results

From single-leg to double-leg standing radiographs MPTA and KAJA did not change significantly, whereas the other measurements showed significant changes: JLOAF, JLOAM and JLOAT decreased 0.88°, 1.24° and 1.77°, MJLA and JLCA decreased 0.63° and 0.85°, and HKA increased 1.11° (p < 0.05). Bipedal distance in double-leg standing radiographs moderately correlated with JLOAF, JLOAM and JLOAT (rp = -0.555, -0.574 and -0.549). Osteoarthritis grade moderately correlated with JLCA in single-leg and double-leg standing radiographs (rs = 0.518 and 0.471). All measurements had at least good reliability.

Conclusion

In long-standing radiographs, measurements of JLOAF, JLOAM, JLOAT, MJLA, JLCA and HKA are all influenced by single-leg/double-leg standing; JLOAF, JLOAM and JLOAT are also affected by bipedal distance in double-leg standing; and JLCA is affected by osteoarthritis grade. Knee joint obliquity as assessed by MPTA measurement is independent of single-leg/double-leg standing, bipedal distance or osteoarthritis grade, and has excellent measurement reliability. We therefore propose MPTA as the preferable KJLO measurement method for clinical practice and future research.

Level of evidence

III, cross-sectional study.

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.

High tibial osteotomy to neutral alignment improves medial knee articular cartilage composition

PURPOSE

The purpose of this study was to: (1) test the hypothesis that HTO improves articular cartilage composition in the medial compartment without adversely affecting the lateral compartment and patella, and; (2) explore associations between knee alignment and cartilage composition after surgery.

METHODS

3T MRI and standing radiographs were obtained from 34 patients before and 1-year after HTO. Articular cartilage was segmented from T2 maps. Mechanical axis angle (MAA), posterior tibial slope, and patellar height were measured from radiographs. Changes in T2 and radiographic measures were assessed using paired t tests, and associations were assessed using Pearson correlation coefficients.

RESULTS

The mean (SD) MAA before and after HTO was - 6.5° (2.4) and 0.6° (3.0), respectively. There was statistically significant shortening [mean (95%CI)] of T2 in the medial femur [- 2.8 ms (- 4.2; - 1.3), p < 0.001] and medial tibia [- 2.2 ms (- 3.3; - 1.0), p < 0.001], without changes in the lateral femur [- 0.5 ms (- 1.6; 0.6), p = 0.3], lateral tibia [0.2 ms (- 0.8; 1.1), p = NS], or patella [0.5 ms (- 1.0; 2.1), p = NS). Associations between radiographic measures and T2 were low. 23% of the increase in lateral femur T2 was explained by postoperative posterior tibial slope (r = 0.48).

CONCLUSION

Performing medial opening wedge HTO without overcorrection improves articular cartilage composition in the medial compartment of the knee without compromising the lateral compartment or the patella. Although further research is required, these results suggest HTO is a disease structure-modifying treatment for knee OA.

Compositions and Structural Geometries of Scaffolds Used in the Regeneration of Cleft Palates: A Review of the Literature

Cleft palate (CP) is one of the most common birth defects, presenting a multitude of negative impacts on the health of the patient. It also leads to increased mortality at all stages of life, economic costs and psychosocial effects. The embryological development of CP has been outlined thanks to the advances made in recent years due to biomolecular successions. The etiology is broad and combines certain environmental and genetic factors. Currently, all surgical interventions work off the principle of restoring the area of the fissure and aesthetics of the patient, making use of bone substitutes. These can involve biological products, such as a demineralized bone matrix, as well as natural–synthetic polymers, and can be supplemented with nutrients or growth factors. For this reason, the following review analyzes different biomaterials in which nutrients or biomolecules have been added to improve the bioactive properties of the tissue construct to regenerate new bone, taking into account the greatest limitations of this approach, which are its use for bone substitutes for large areas exclusively and the lack of vascularity. Bone tissue engineering is a promising field, since it favors the development of porous synthetic substitutes with the ability to promote rapid and extensive vascularization within their structures for the regeneration of the CP area.

Overweight patients benefit from high tibial osteotomy to the same extent as patients with normal weights but show inferior mid-term results

PURPOSE

The purpose of this prospective study was to analyze the impact of obesity on the clinical and radiological outcomes 6 years after open-wedge high tibial osteotomy (HTO).

METHODS

A total of 120 prospectively recorded patients with medial compartment osteoarthritis underwent open-wedge HTO between 2008 and 2011. The study cohort was frequently examined over a minimum of a 6-year follow-up. The cohort was divided into three groups according to body mass index (BMI): normal weight patients (BMI < 25 kg/m²), pre-obese patients (BMI 25-30 kg/m²) and obese patients (BMI > 30 kg/m²). Clinical and functional outcomes (Oxford Knee Score, Hospital for Special Surgery Score, Lequesne Score, Tegner Activity Scale), subjective health-related quality of life (SF-36), change in mechanical limb alignment (mTFA) as well as conversion to unicompartmental or total knee arthroplasty (TKA) were evaluated. To compare clinical scoring between the groups, univariate variance analysis was applied. Changes in outcome variables over time were analyzed with dependent t tests.

RESULTS

From 120 patients, 85 were followed-up over a 6.7-year period on average (6-11.8 years) after HTO. The mean BMI was 28.6 ± 4.6 kg/m². Each group showed a significant pre- to postoperative increase in all recorded scores (p < 0.05). In absolute terms, both mental and clinical scores of overweight patients did not reach the peak values of the normal weighted population during the period of observation. There was a conversion to TKA in 10.5% after an average of 50.1 ± 25.0 months following surgery. A total of five complications occurred without significant differences (BMI < 25: n = 1, BMI 25-30: n = 2, BMI > 30: n = 2; n.s.). There was a mean pre- to postoperative (six weeks after surgery) correction difference of 6.9° ± 3.2° (mTFA) with higher loss of correction over time in overweight patients.

CONCLUSION

In terms of clinical outcome and health-related quality of life, overweight patients may receive a benefit from open-wedge HTO to the same extent as patients with normal weights and show similar complication rates. However, they have inferior preoperative clinical and functional results and mid-term results after open-wedge HTO compared to patients with normal weights.

LEVEL OF EVIDENCE

Level III.

Good long-term survival and patient-reported outcomes after high tibial osteotomy for medial compartment osteoarthritis

The lateral closing and medial opening wedge high tibial osteotomy can correct a varus malalignment of the knee caused by medial compartment osteoarthritis. These procedures have produced great short-term and mid-term results. As no systematic review has examined their long-term results yet, the goal of this article was to compare the results of all articles about lateral closing and medial opening wedge high tibial osteotomies, published after the year 2000, with a mean follow-up of more than 10 years. A systematic search of the Medline, Web of Science and Cochrane databases resulted in the inclusion of 30 articles. All these studies combined examined the results of 7087 high tibial osteotomies in a total of 6636 patients after a mean follow-up of more than 10 years. Primary outcome measures were the survival rate of the osteotomy, functional scores, patient satisfaction and pain scores. Secondary outcome measures were alignment correction and the identification of factors influencing the survival of the osteotomy. The 5-year, 10-year, 15-year and 20-year survival rates, respectively, ranged from 86 to 100%, 64-97.6%, 44-93.2% and 46-85.1%. The subjective scoring systems showed an improvement postoperatively that was maintained until final follow-up. The anatomical and mechanical tibiofemoral axis were, respectively, corrected to a mean of 7.3°-13.8° of valgus and 0.6°-4° of valgus. The results of the articles evaluating the influence of potential risk factors were contradictory. Despite the low quality of the available evidence, the lateral closing and medial opening wedge high tibial osteotomy seem to remain valid long-term treatment options for patients with painful varus malalignment caused by isolated medial compartment osteoarthritis of the knee. The available results indicate that the need for arthroplasty could be delayed for more than 15 years in the majority of patients. However, higher-quality studies are needed to confirm these findings. As a systematic review is assigned a level of evidence equivalent to the lowest level of evidence used from the analyzed manuscripts, the level of evidence of this systematic review is IV.

No difference in union and recurrence rate between iliac crest autograft versus allograft following medial opening wedge high tibial osteotomy: a randomized controlled trial

PURPOSE

Using iliac crest autograft has been considered as gold standard for gap filling in medial opening wedge high tibial osteotomy (MOW-HTO) but is associated with donor site morbidity and pain. The purpose of this study was to compare the results of the use of iliac crest autograft versus allograft from the same anatomic site in terms of union and recurrence.

METHODS

Forty-six patients with genovarum with or without medial compartment osteoarthritis were enrolled based on specific inclusion and exclusion criteria and were randomly assigned into two groups. MOW-HTO was done using iliac crest allograft (23 patients) or autograft (23 patients) as void filler. Follow-up visits were done monthly for the first 3 months and then every 3 months until 1 year and then at 5th and 8th postoperative year. The clinical assessment of union, anatomical indices of proximal tibia, complications and WOMAC score were assessed for both groups.

RESULTS

The amount of correction (degrees), recurrence, complication rates, time to get symptom-free, radiologic union and knee scores was similar in both groups. The symptom-free time was 6.1 (SD = 0.9) weeks in autograft group versus 6.2 (SD = 0.8) weeks in allograft group (p = 0.73, 95% CI  - 0.4 to 0.6). The time to radiologic union had a between-group difference of 0.3 weeks (p = 0.58, 95% CI  - 1.6 to 0.9). There was one case of surgical site infection in graft harvest site. No nonunion or delayed union was encountered in either group. Fifty-two percent of the autograft patients reported more intense postoperative pain in iliac graft harvest site than tibial osteotomy site.

CONCLUSIONS

According to our results, iliac crest allograft can be safely used in MOW-HTO with comparable efficacy and safety to iliac crest autograft.

CLINICAL TRIAL REGISTRY

The clinical trial was approved by clinicaltrial.gov with identifier NCT00595712.

Total knee replacement after high tibial osteotomy: time-to-event analysis and predictors

BACKGROUND:

An important aim of high tibial osteotomy (HTO) is to prevent or delay the need for total knee replacement (TKR). We sought to estimate the frequency and timing of conversion from HTO to TKR and the factors associated with it.

METHODS:

We prospectively evaluated patients with osteoarthritis (OA) of the knee who underwent medial opening wedge HTO from 2002 to 2014 and analyzed the cumulative incidence of TKR in July 2019. The presence or absence of TKR on the HTO limb was identified from the orthopedic surgery reports and knee radiographs contained in the electronic medical records for each patient at London Health Sciences Centre. We used cumulative incidence curves to evaluate the primary outcome of time to TKR. We used multivariable Cox proportional hazards analysis to assess potential preoperative predictors including radiographic disease severity, malalignment, correction size, pain, sex, age, body mass index (BMI) and year of surgery.

RESULTS:

Among 556 patients who underwent 643 HTO procedures, the cumulative incidence of TKR was 5% (95% confidence interval [CI] 3%–7%) at 5 years and 21% (95% CI 17%–26%) at 10 years. With the Cox proportional hazards multivariable model, the following preoperative factors were significantly associated with an increased rate of conversion: radiographic OA severity (adjusted hazard ratio [HR] 1.96, 95% CI 1.12–3.45), pain (adjusted HR 0.85, 95% CI 0.75–0.96)], female sex (adjusted HR 1.67, 95% CI 1.08–2.58), age (adjusted HR 1.50 per 10 yr, 95% CI 1.17–1.93) and BMI (adjusted HR 1.31 per 5 kng/m², 95% CI 1.12–1.53).

INTERPRETATION:

We found that 79% of knees did not undergo TKR within 10 years after undergoing medial opening wedge HTO. The strongest predictor of conversion to TKR is greater radiographic disease at the time of HTO.

Complications, Additional Surgery, and Joint Survival Analysis After Medial Open-Wedge High Tibial Osteotomy

The reported incidence of complications following medial open-wedge high tibial osteotomy (MOWHTO) varies. The authors sought to assess the complications, additional surgeries, and joint survival following MOWHTO in patients with isolated medial compartment arthrosis during a mean follow-up of 10 years. This retrospective study involved patients implanted with spacer plates, angle adjustable plates, or inverse L-type plates with wedges between 2000 and 2010. A total of 504 knees from 441 patients were examined. Mean age of the study population was 52.6±7.0 years, with 56 (11.1%) knees from men and 448 (88.9%) from women. The 10-year Kaplan-Meier joint survival rate was 94.8%. Overall complication rate for MOWHTO was 63.7%, with complications in 20.3% of treated knees requiring additional surgery. In this population, although the overall complication rate and the need for additional surgery were high, the need for additional surgery resulting from serious complications was low (2.6%). The high joint survival rate and low rate of additional surgery for serious complications indicate that MOWHTO can be safely applied in patients with isolated medial gonarthrosis. [Orthopedics. 2020;43(5):303-314.].

Accuracy of the correction obtained after tibial valgus osteotomy. Comparison of the use of the Hernigou table and the so-called classical method

INTRODUCTION

Medial valgus-producing tibial osteotomy (MVTO) is classically used to treat early medial femorotibial osteoarthritis. Long-term results depend on the mechanical femorotibial angle (HKA) obtained at the end of the procedure. A correction goal between 3 and 6° valgus is commonly accepted. Several planning methods are described to achieve this goal, but none is superior to the other.

OBJECTIVE

The main objective was to compare the accuracy of the correction obtained using either the Hernigou table (HT) or a so-called conventional method (CM) for which 1° of correction corresponds to 1° of osteotomy opening. The secondary objective was to analyze the variations observed in the sagittal plane on the tibial slope and on the patellar height. The working hypothesis was that the HT allowed a more accurate correction and that the tibial slope and patellar height were modified in both groups.

MATERIAL AND METHOD

In this monocentric and retrospective study, two senior surgeons operated on 39 knees (18 in the CM group, 21 in the HT group) between January 1, 2009 and December 31, 2014. The operator was unique for each group and expert in the technique used. The correction objective chosen for each patient, and written in the operative report, was considered as the one to be achieved. The surgical correction was the difference between the pre-operative and immediate post-operative data (< 5 J) for the mechanical tibial angle (MTA) and the hip-knee-ankle (HKA) angle. Surgical accuracy, where a value close to 0 is optimal, was the absolute value of the difference between the surgical correction performed and the goal set by the surgeon.

RESULTS

The median surgical accuracy on the MTA was 3.5° [0.2-7.4] versus 1.4° [0-4.1] in the CM and HT groups, respectively (p = 0.006). In multivariate analysis, with the same objective, the CM had a significantly lower accuracy of 1.9° ± 0.8 (p = 0.02). For HKA, the median accuracy was 3.1° [0.3-7.3] versus 0.8° [0-5] in the CM and HT groups, respectively (p = 0.006). Five (5/18, 28%) and 16 (16/21, 76%) knees were within 3° of the target in the CM and HT groups, respectively (p = 0.004). The median tibial slope increased in both groups. This increase was significantly greater in the CM group compared with the HT group, with 5.5° [- 0.3-13] versus 0.5 [- 5.2-5.6], respectively (p < 0.001). The median Caton-Deschamps index decreased (patella lowered) in both groups after surgery, by - 0.21 [- 1.03; - 0.05] and - 0.14 [- 0.4-0.16], but without significant difference (p = 0.19). In univariate analysis, changes in tibial slope and patellar height were not significantly related to frontal surgical correction performed according to ΔMTA (R² = 0.07; p = 0.055) and (R² = - 0.02; p = 0.54) respectively.

DISCUSSION

The correction set by the surgeons was achieved with greater accuracy and more frequently in the HT group, confirming the working hypothesis. The HT is therefore recommended as a simple way of achieving the set objective; the tibial slope and patellar height were modified unaffected by the frontal correction performed.

Mid-term CT assessment of bone healing after nanohydroxyapatite augmentation in open-wedge high tibial osteotomy

BACKGROUND

The aim of the present study was to confirm the effectiveness of adding nanohydroxyapatite (NHA) to a heterologous bone graft in open-wedge high tibial osteotomy (OWHTO) by measuring the bone density via multislice computed tomography (CT) of the tibial osteotomy gap in a mid-term follow-up (five years).

METHODS

Twenty-six patients undergoing OWHTO were randomly assigned to two groups: a pure graft group (Group A), in which the osteotomy gap was filled with only heterologous bone graft, and an NHA group (Group B), in which the osteotomy gap was filled with heterologous bone graft and NHA. CT was performed within one week of the operation, after two months, after 12 months and after five years. CT volume acquired in Hounsfield units (HU) was measured on three planes.

RESULTS

The normal bone density was 110.2 ± 11.7 HU. The value of mean density at five years in Group A was 296.8 ± 81.8 HU, while in Group B, it was 202.2 ± 45.1 HU, showing a density more similar to normal bone and greater bone uniformity inside the osteotomy. The difference between the two groups was statistically significant (p < 0.05). Furthermore, both groups showed excellent mid-term clinical outcomes without significant differences.

CONCLUSIONS

This study revealed that absorbability and bone formation at the osteotomy site in the NHA group was significantly higher as compared with the pure graft group at five years postoperatively.

Clinical Outcomes and Complications During and After Medial Open-Wedge High Tibial Osteotomy Using a Locking Plate: A 3- to 7-Year Follow-up Study

Background:

Outcomes and complications at mid- or long-term follow-up after medial open-wedge high tibial osteotomy (MOWHTO) with the TomoFix locking plate have not been fully evaluated.

Purpose:

To evaluate the complications and midterm clinical outcomes after MOWHTO using a TomoFix.

Study Design:

Case series; Level of evidence, 4.

Methods:

Enrolled in this study were 80 patients (85 knees) who underwent MOWHTO with the TomoFix locking plate between 2009 and 2013. There were 66 women and 14 men, with a mean age of 61.5 years at the time of surgery. The diagnosis was medial osteoarthritis in 76 knees and spontaneous osteonecrosis of the knee in 9 knees. Metal removal and second-look arthroscopy were performed in all cases. Clinical and radiological examinations were performed at final follow-up after surgery (mean, 4.5 years).

Results:

The mean Japanese Orthopaedic Association score and Knee injury and Osteoarthritis Outcome Score improved significantly from pre- to postoperatively (P < .0001). The weightbearing line percentage shifted to pass through a point 67.7% lateral from the medial edge of the tibial plateau. The Caton-Deschamps index changed significantly from 0.88 to 0.66 at final follow-up (P < .0001). The mean posterior tibial slope changed significantly from 8.9° to 11.9° at final follow-up (P < .0001). Limb length was significantly increased after MOWHTO (10.3 mm; P < .0001). During plate removal, 14 locking screws were found to be broken in 9 knees (10.6%). The articular cartilage grade of the patellofemoral joint was significantly higher in the second arthroscopy than in the first arthroscopy (P < .0001). The cumulative rate of all complications was 41.2%, with major complications (ie, those requiring additional or extended treatment) in 24.7%.

Conclusion:

Postoperative outcome scores indicated significant improvement after MOWHTO, although the cumulative rate of all complications was 41.2% and the rate of major complications was 24.7%. These results indicate that MOWHTO with the TomoFix is a technically demanding procedure. Careful preoperative planning and meticulous surgical technique are needed to decrease the incidence of complications associated with MOWHTO.

Satisfactory long-term survival, functional and radiological outcomes of open-wedge high tibial osteotomy for managing knee osteoarthritis: Minimum 10-year follow-up study

Background

This prospective cohort study was designed to evaluate the survivorship and functional outcomes associated with long-term results of medial open-wedge high tibial osteotomy (MOWHTO) for the treatment of medial compartment knee osteoarthritis in the Chinese population. Although MOWHTO is a well-established procedure in the management of medial osteoarthritis of the knee, the long-term outcome in the Chinese population has not been reported in current literature. We hypothesised that MOWHTO would result in long-term preservation of knee function in Chinese, similar to that reported in the Caucasian population.

Methods

A cohort of 22 young adult patients (age < 55 years old) undergoing MOWHTO for the treatment of symptomatic medial compartment knee osteoarthritis between 2002 and 2008 was retrospectively surveyed with a minimum follow-up of 10 years. Kaplan–Meier survival analysis was performed, and the failure modes were investigated. The outcomes on survival (not requiring arthroplasty), clinical outcome (Knee Society Knee Score and Knee Society Function Score) and range of motion (numeric rating scale) at preoperative, 1-year postoperative follow-up and at last follow-up (>10 years) were evaluated. In addition, the mechanical tibiofemoral angle was also measured. The Wilcoxon signed-rank test was used for statistical evaluation of nonparametric data in these related samples.

Result

A total of 31 knees in these 22 cases were included. The follow-up rate was 100% at 13.4 ± 1.9 years (11–17). Mean age at time of surgery was 45.8 ± 9.5 years (18–53). At 10-year follow-up, four knees converted to require total knee arthroplasty (survival: 87.1%). Preoperative varus alignment with mechanical tibiofemoral angle of −9.26 ± 2.83 was corrected to 2.58 ± 2.46 after surgery and remained 2.01 ± 3.52 at the latest follow-up. Knee Society Knee Score increased significantly from 53.7 ± 11.1 preoperatively to 93.8 ± 6.8 at 1-year follow-up and 91.8 ± 9.7 at latest follow-up. Similarly, the functional score also increased significantly from 67.4 ± 21.0 preoperatively to 86.3 ± 14.5 at 1-year follow-up and 82.1 ± 16.6 at latest follow-up (p < 0.01). Whereas, the range of motion significantly decreased from 122.7 ± 6.6 preoperatively to 116.1 ± 15.5 at the latest follow-up.

Conclusion

Even in cases of severe medial osteoarthritis and varus malalignment, MOWHTO would be a good treatment option for management in active Chinese population less than 55 years. Although the long-term survival and functional outcome after MOWHTO was proven to be satisfactory in our cohort during the 10-year follow-up, a larger cohort to illustrate the long-term functional outcome is still warranted.

Translational potential

The finding in this study indicated MOWHTO is a feasible treatment option for young adult patients with osteoarthritis to achieve long-term satisfactory results.

Plate-related results of opening wedge high tibial osteotomy with a carbon fiber reinforced poly-ether-ether-ketone (CF-PEEK) plate fixation: a retrospective case series of 346 knees

BACKGROUND

While open wedge high tibial osteotomy (owHTO) is an established standard procedure to treat medial osteoarthritis of the knee in combination with varus deformity, it bears the risk of postoperative hardware failures and lateral cortical hinge fractures. This in turn can lead to an accelerated osteoarthritis, non-union, or a loss of correction accuracy. The purpose of the study was to evaluate the radiologic outcomes of owHTO with a carbon fiber reinforced poly-ether-ether-ketone (CF-PEEK) plate fixation in patients with medial osteoarthritis and varus deformity.

METHODS

Three hundred twenty-four consecutive patients (346 knees) who were treated with owHTO using the PEEKPower HTO plate were included in this retrospective study; 89.9% of the patients were overweight or obese. Patients were followed by conventional radiographs over a 12-month period. Typical plate-related results such as the time and quality of gap healing as well as the correction accuracy were analyzed. Furthermore, the number of lateral cortex fractures was determined.

RESULTS

Bony consolidation was observed after a mean gap healing time of 4.0 ± 1.7 months independent on the patients' weight (p = 0.2302). With increasing gap sizes, bony healing was significantly prolonged (p < 0.001). Additionally, patients with greater gap sizes had a significantly increased risk for a lateral cortex fracture (p = 0.0041). However, none of the patients had a non-union 1 year postoperative. A hinge fracture occurred in 30% of patients. Hinge fractures with Takeuchi grades I and II increased the gap healing time compared to no fracture (p = 0.0069 and p = 0.0002, respectively), but only 1.2% of patients with hinge fracture had a clinical relevant loss of correction ≥ 3 mm. No implant failures were found.

CONCLUSIONS

Open wedge HTO using the PEEKPower HTO plate for patients with medial osteoarthritis of the knee in combination with tibial varus deformity leads to excellent bony consolidation also in cases with a hinge fracture, a gap size > 12 mm as well as for severely obese patients.

Factors affecting stability after medial opening wedge high tibial osteotomy using locking plate: A cadaveric study

OBJECTIVES

To investigate the effect of screw length, lateral hinge fracture, and gap filling on stability after medial opening wedge high tibial osteotomy (MOW HTO) using a locking plate.

METHODS

Forty tibiae from fresh-frozen cadavers were randomly allocated into five groups. Group A was bicortically fixated, while Group B and Group C were unicortically fixated: 90% and 55% of drilled tunnel length, respectively. Group D was fixated using 90% length screws with a fractured lateral hinge. Group E was fixated using 90% length screws with gap filling using a bone substitute. Operated tibiae were tested under axial compressive load using a material testing machine. The medial gap changes under the serial axial load of 100-600 N and ultimate failure load were measured.

RESULTS

Group D showed the biggest medial gap change and lowest failure load, while Group E presented the smallest gap change and highest failure load. The medial gap changes tended to increase with shorter screw length, but the difference was not significant between Groups A, B, and C. Group C and Group D showed greater medial gap change and lower failure load compared with Group E, while not differing from Group A and Group B.

CONCLUSIONS

Unicortical fixation in proximal screw holes of a locking plate was not inferior to bicortical fixation regarding axial stability in MOW HTO, although proximal screws that are too short should be avoided. Lateral hinge fracture decreased, while gap filling with bone substitute increased axial stability.

Assessment of valgus laxity after release of the medial structure in medial open-wedge high tibial osteotomy: an in vivo biomechanical study using quantitative valgus stress radiography

Background

To perform medial open-wedge high tibial osteotomy (OWHTO), surgeons expose the medial-proximal tibia by releasing or cutting the superficial layer of the medial collateral ligament (sMCL). Biomechanically, the sMCL provides primary restraint against valgus forces. Therefore, any release of the sMCL can cause valgus instability of the knee joint. The purpose of this study was to assess valgus laxity after release of the medial structure of the knee during OWHTO.

Methods

Between 2009 and 2015, 84 consecutive patients (93 knees) who underwent OWHTO using a locking plate were enrolled in this study. All patients underwent radiological examinations before surgery, during surgery, 1 year after surgery, and after plate removal to objectively assess valgus laxity. The medial joint space (MJS) and the joint line convergence angle (JLCA) of the knee were evaluated using quantitative valgus stress radiography. Clinical evaluation was performed 2 years after surgery.

Results

The mean functional knee score improved significantly, from 65.5 to 91.1 points (p < 0.0001). The mechanical axis percentage shifted to pass through a point 69.7% lateral from the medial edge of the tibial plateau. The MJS and JLCA increased significantly during OWHTO surgery (11.0 mm, 7.4 °, p < 0.0001). However, no significant differences were noted in the MJS and JLCA among preoperative, 1-year postoperative periods and after plate removal.

Conclusion

Valgus laxity was significantly greater after release of the sMCL. However, no significant differences were noted in valgus laxity in preoperative, 1-year postoperative periods and after plate removal. Complete release of the sMCL did not cause postoperative valgus laxity after OWHTO surgery.

Trial registration

Trial registration number: No.012–0360.

A pilot study to assess the safety and radiological performance of a new low-profile locking plate for high tibial osteotomy

BACKGROUND

We report the first results of a new low-profile titanium locking plate for fixation of opening wedge high tibial osteotomy (OWHTO). Short spacer plates have been associated with a high hardware complication rate, whilst fixed angle locking plates have been associated with a high incidence of soft tissue irritation. This plate aims to achieve stable fixation whilst maintaining a low profile, allowing space for combined procedures.

METHODS

All patients undergoing OWHTO with the Activmotion plate were retrospectively reviewed. Patients were allowed to progress to full weight bearing after two weeks. Radiographic assessment included the medial proximal tibial angle (MPTA) and posterior tibial slope at six weeks and then three monthly until union. All complications were recorded.

RESULTS

Thirty-seven patients with 40 OWHTOs were included in the study. The mean MPTA increased from 85.2 preoperatively to 91.9 postop. Tibial slope changed from 5.2 to 4.2°. The correction was sustained until union with no loss of correction in the MPTA (median change 0.0, 95% CI for median (-0.25, 0.4)) or tibial slope (mean increase 0.32, 95% CI (-0.02, 0.67)).

CONCLUSIONS

In this pilot study the Activmotion plate raised no safety concerns with regard to implant related adverse events or loss of initial correction. Early rehabilitation with immediate partial weight bearing was possible and all cases proceeded to osteotomy union with the exception of one case that needed to undergo bone grafting with implant retention. Premature removal of the implant was necessary in four cases due to symptomatic hardware irritation.

Comparison of navigated and conventional high tibial osteotomy for the treatment of osteoarthritic knees with varus deformity: A meta-analysis

BACKGROUND

High tibial osteotomy (HTO) is a usefully surgical procedure to correct the malalignment and delay the progression of osteoarthritis. It is still controversy whether navigation system can offer more accuracy of targeted alignment and achieve better clinical outcomes than conventional method. The purpose of present meta-analysis was to investigate whether navigation system was superior to conventional method with regard to clinical and radiographic outcomes.

METHOD

The included studies compared the clinical and radiographic outcomes between navigated HTO group and conventional group. The clinical assessments were Lysholm Score, AKS Function Score and Arc of motion, and the radiographic outcomes were Mechanical axis (MA), Weight bearing line ratio (WBL), Outliers of alignment and Change in TPS used to evaluate alignment correction. The meta-analysis was performed using Review Manager 5.3 software. Downs and Black and the Newcastle-Ottawa Scale (NOS) were used to evaluate the study quality.

RESULT

Sixteen studies were eligible in present meta-analysis, including thirteen studies concerning opening wedge HTO and three studies involving closing wedge HTO. Clinical outcomes were only reported in studies which used opening wedge HTO. No significant differences were observed in all clinical outcomes between navigated and conventional HTO. Regarding radiographic outcomes, no significant difference in WBL ratio was observed between navigated and conventional HTO. Patients undergoing navigated HTO were associated with significantly greater in MA and lower in Outliers of alignment compared with those undergoing conventional HTO. Compared with conventional HTO, increase in TPS was significantly lower in navigated HTO group using opening wedge HTO, but decrease in TPS was significantly greater in navigated HTO group using closing wedge HTO.

CONCLUSION

Our meta-analysis demonstrated that navigated HTO offered more accuracy and precision of alignment correction, except WBL ratio. However, better clinical outcomes were not observed in navigation group.

The effect of wedge and tibial slope angles on knee contact pressure and kinematics following medial opening-wedge high tibial osteotomy

BACKGROUND

High tibial osteotomy is a surgical procedure to treat medial compartment osteoarthritis in varus knees. The reported success rates of the procedure are inconsistent, which may be due to sagittal plane alignment of the osteotomy. The objective of this study was to determine the effect of changing tibial slope, for a range of tibial wedge angles in high tibial osteotomy, on knee joint contact pressure location and kinematics during continuous loaded flexion/extension.

METHODS

Seven cadaveric knee specimens were cycled through flexion and extension in an Oxford knee-loading rig. The osteotomy on each specimen was adjusted to seven clinically relevant wedge and slope combinations. We used pressure sensors to determine the position of the centre of pressure in each compartment of the tibial plateau and infrared motion capture markers to determine tibiofemoral and patellofemoral kinematics.

FINDINGS

In early knee flexion, a 5° increase in tibial slope shifted the centre of pressure in the medial compartment anteriorly by 4.5mm (P≤0.001), (from the neutral slope/wedge position). Increasing the tibial slope also resulted in the tibia translating anteriorly (P≤0.001).

INTERPRETATION

Changes to the tibial slope during high tibial osteotomy for all tested wedge angles shifted the centre of pressure in both the medial and lateral compartments substantially and altered knee kinematics. Tibial slope should be controlled during high tibial osteotomy to prevent unwanted changes in tibial plateau contact loads.

Bone substitutes: a review of their characteristics, clinical use, and perspectives for large bone defects management

Bone replacement might have been practiced for centuries with various materials of natural origin, but had rarely met success until the late 19th century. Nowadays, many different bone substitutes can be used. They can be either derived from biological products such as demineralized bone matrix, platelet-rich plasma, hydroxyapatite, adjunction of growth factors (like bone morphogenetic protein) or synthetic such as calcium sulfate, tri-calcium phosphate ceramics, bioactive glasses, or polymer-based substitutes. All these substitutes are not suitable for every clinical use, and they have to be chosen selectively depending on their purpose. Thus, this review aims to highlight the principal characteristics of the most commonly used bone substitutes and to give some directions concerning their clinical use, as spine fusion, open-wedge tibial osteotomy, long bone fracture, oral and maxillofacial surgery, or periodontal treatments. However, the main limitations to bone substitutes use remain the management of large defects and the lack of vascularization in their central part, which is likely to appear following their utilization. In the field of bone tissue engineering, developing porous synthetic substitutes able to support a faster and a wider vascularization within their structure seems to be a promising way of research.

Early weight bearing versus delayed weight bearing in medial opening wedge high tibial osteotomy: a randomized controlled trial

PURPOSE

The need for a period of non-weight bearing after medial opening wedge high tibial osteotomy remains controversial. It is hypothesized that immediate weight bearing after medial opening wedge high tibial osteotomy would have no difference in functional scores at one year compared to delayed weight bearing.

METHODS

Fifty patients, median age 54 years (range 40-65), with medial compartment osteoarthritis, underwent a medial opening wedge high tibial osteotomy utilizing a locking plate without bone grafting. Patients were randomized into an Immediate or a Delayed (2 months) weight bearing group. All patients were assessed at one-year follow-up and the two groups compared. The primary outcome measure was the IKS score. Secondary outcome measures included the IKDC score, the VAS pain score and rate of complications.

RESULTS

The functional scores significantly improved in both groups. The IKS score increased from 142 ± 31 to 171 ± 26 in the Immediate group (p < 0.001) and from 148 ± 22 to 178 ± 23 in the Delayed group (p < 0.001). The IKDC score increased from 49 ± 17 pre-operatively to 68 ± 14 one-year post-operatively in the Immediate group (p < 0.0001) and from 44 ± 16 to 69 ± 19 in the Delayed group (p < 0.001). The average VAS for pain 2 months after surgery was 3 ± 3 in the Immediate group and 3 ± 2 in the Delayed (n.s.). There was no significant difference between the two groups in any of the outcome measures. The mean mechanical femorotibial angle changed from 6° of varus (0°-15° of varus, SD = 3°) to 4° of valgus (5°-11° of valgus, SD = 3°) in the Immediate group and from 5° of varus (0°-10° of varus, SD = 3°) to 3° of valgus (2° of varus to 8° of valgus, SD = 3°) in the Delayed group. No difference was seen between groups, and no loss of correction was observed in any patient. Two cases of non-union occurred, one in each group. One infection and one deep vein thrombosis occurred in the Immediate group.

CONCLUSION

Immediate weight bearing after medial opening wedge high tibial osteotomy had no effect on functional scores at 1 year follow-up and did not significantly increase the complication rate. Immediate weight bearing after medial opening wedge high tibial osteotomy appears to be safe and can allow some patients a quicker return to activities of daily living and a decreased convalescence period.

LEVEL OF EVIDENCE

II.

Multicompartmental Osteochondral Allografts of Knee and Concomitant High Tibial Osteotomy

Chondral lesions of the knee can occur secondary to limb malalignment. To address these interrelated problems, a high tibial osteotomy with concomitant osteochondral allograft transfer may be performed. It is important to address these chondral lesions as they often affect the young and active population and cause morbidity in an otherwise healthy population. Although numerous approaches for the treatment of chondral lesions have been described, long-term results demonstrating regeneration of hyaline cartilage have yet to be reported. Furthermore, larger, full-thickness cartilage defects, which can be caused by limb malalignment, have proven to be particularly challenging to treat. This Technical Note details our technique for multicompartmental osteochondral allograft transplantation with concomitant high tibial osteotomy in a patient with 2 focal cartilage lesions in the knee.

Survival of opening versus closing wedge high tibial osteotomy: A meta-analysis

This meta-analysis was designed to compare the longevity of the survivorship of opening versus closing wedge high tibial osteotomy (HTO). All studies reporting survival rates in patients who underwent open or closed wedge HTO with more than 5-year follow-up duration were included in the meta-analysis. Survival time was considered as time to conversion to TKA. Twenty three studies were included in meta-analysis, 20 of which were of level IV evidence. The pooled 5-year survival rates were 95.1% (95% CI: 93.1 to 97.1%) in open wedge HTO and 93.9% (95% CI: 93.1 to 94.6%) in closed wedge HTO. Although there was 1.2% greater survival rate in open wedge HTO than in closed wedge HTO, this difference did not reach statistical significance (P = 0.419). Pooled 10-year survival rates were 91.6% (95% CI: 88.5 to 94.8%) in open wedge HTO and 85.4% (95% CI: 84.0 to 86.7%) in closed wedge HTO, indicating that open wedge HTO had 6.2% greater survival rate 10 years after surgery than did closed wedge HTO (P = 0.002). No difference in 5-year survivorship was found between open- and closed-wedge HTO. However, the survival rate was higher in open-wedge HTOs than in closed wedge HTO at 10 years.

Autologous Bone Grafting and Revision Plating in a Case of Persistent High Tibial Osteotomy Non-Union

Introduction:

Uni-compartmental knee arthritis may be treated with several surgical options including uni-compartmental knee arthroplasty, total knee arthroplasty and high tibial osteotomy. Non-union is a well-established and common complication that may arise from the latter option and few reports have shown successful treatment of persistent non-union of high tibial osteotomy.

Case Presentation:

We present a case of persistent non-union after high tibial osteotomy treated with autologous iliac crest bone grafting and revision plating. At 1 year post-operative interval, successful union was achieved after revision internal fixation. In addition, a good functional outcome was achieved.

Conclusion:

In this patient with persistent non-union following high tibial osteotomy, the aim of revision was to restore alignment and effect bone healing while preserving adequate tibial bone stock. Revision plating with autologous bone grafting is a good surgical strategy in the treatment ofpersistent non-union with hardware failure.

Comparison of osteoconductivity and absorbability of beta-tricalcium phosphate and hydroxyapatite in clinical scenario of opening wedge high tibial osteotomy

The purpose of this study was to compare the osteoconductivity, and absorbability of hydroxyapatite or beta-tricalcium phosphate in clinical scenario of opening wedge high tibial osteotomy Total 41 knees of 40 patients with follow up period of more than 1 year were enrolled. These patients were divided into two groups, Group I (22 knees, 21 patients) used hydroxyapatite and Group II (19 knees, 19 patients) used beta-tricalcium phosphate as a substitute in the opening gap. According to proven method, the osteoconductivity was assessed radiographically by the extent of new bone formation at osteotomy space and absorbability was evaluated by measuring the area occupied by substitute at immediate postoperative, postoperative 6 months and 1 year. Regarding preoperative demographic data, no significant differences were found between two groups. No statistically significant differences were found between two groups regarding lower limb alignment (mechanical femorotibial angle, weight-bearing line%) and posterior tibial slope at postoperative and final follow up radiographs. Concerning the osteoconductivity, there were no significant differences between two groups in any zone. However, the absorption rate was significantly greater in the Group II than in Group I at 6 months (Group I: 13.7 ± 6.8, group II: 35.3 ± 15.8, P = 0.001) and 1 year (Group I: 24.2 ± 6.3, Group II: 49.6 ± 14.3, P < 0.0001). The complications related to bone substitutes were not observed. Both hydroxyapatite and beta-tricalcium phosphate showed satisfactory gap healing without complications and can be successfully used as alternative healing materials in opening wedge high tibial osteotomy. Our study showed that beta-tricalcium phosphate has superior absorbability than hydroxyapatite. But osteoconductivity showed no significant difference.

Comparative Study of Opening-Wedge High Tibial Osteotomy With and Without a Combined Computed Tomography-Based and Image-Free Navigation System

PURPOSE

To assess whether a combined computed tomography (CT)-based and image-free navigation system results in better coronal and sagittal alignment than the conventional method for performing opening-wedge high tibial osteotomy (OWHTO) and whether CT-based navigation results in acquisition of an accurate osteotomy plane.

METHODS

Sixty-two consecutive knees were randomly divided into navigated and conventional groups. The intraoperative correction angle was determined by the change in hip-knee-ankle angle in the navigated group and by the predicted medial opening width in the conventional group. Outliers of femorotibial angle (FTA) and tibial posterior slope (TPS) were defined as angles of >175° or <165° and angles of >2.5° or <-2.5°, respectively. Radiographic and clinical data were compared between the 2 groups at 2 years postoperatively.

RESULTS

Mean postoperative FTAs were 168.5° in the navigated group and 168.1° in the conventional group. Mean change in TPS of -0.2° in the navigated group was significantly lower than that of 1.6° in the conventional group (P = .005). On postoperative CT, mean angle between the tibial plateau and osteotomy planes in the sagittal plane showed a significantly higher anterior opening of 12° in the conventional than in the navigated group (P < .001). There was a significantly greater proportion of TPS outliers in the conventional (51.6%) than in the navigated group (12.9%) (P = .001), and a significantly greater proportion within the normal range in both planes in the navigated (74.2%) than in the conventional group (48.4%) (P = .037).

CONCLUSIONS

Combined CT-based and image-free navigation in OWHTO better preserves the original TPS and more frequently restores normal coronal and sagittal plane knee joint alignment. CT-based navigation also enabled acquisition of our target osteotomy plane in the sagittal plan. The navigation system in OWHTO was helpful for simultaneous control of the alignment in 2 planes.

LEVEL OF EVIDENCE

Level II, lesser-quality prospective randomized trial.

High tibial osteotomy for the treatment of medial osteoarthritis of the knee with new iBalance system: 2 years of follow-up

BACKGROUND

A new system for performing open-wedge high tibial osteotomy (HTO), the iBalance HTO System-Arthrex, has been recently developed in order to make the surgery more reproducible and safe. The aim of this study was to determine the short-term outcomes of the iBalance technique in medial compartment osteoarthritis and varus malalignment of the knee.

METHODS

Fifteen patients with a mean age of 50.7 years (SD 5.09), affected by symptomatic varus knee, with medial compartment osteoarthritis (1-2 Ahlbäck degree), were treated with iBalance HTO between July 2011 and February 2012 and evaluated retrospectively. Patients were assessed against the following benchmarks: subjective International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and VAS for pain and Tegner scores, along with X-rays and MRI, before surgery and after a 2-year follow-up.

RESULTS

No severe intraoperative complications or implant failures occurred. The mean preoperative scores were as follows: subjective IKDC 66.8 (SD 1.18), KOOS 61.3 (SD 0.86), Vas for pain 8.6 (SD 1.72) and Tegner 4.1 (SD 2.06), while at follow-up the scores were 73.6 (SD 1.01), 88.1 (SD 1.23), 2.9 (SD 2.35) and 3.1 (SD 1.83), respectively. Correction ranged between 3° and 8°. All patients showed complete articular recovery, no loss of correction, no substantial variation in A/P slope and no hardware problems.

CONCLUSIONS

iBalance proved to be effective and safe and produced good overall results. Consolidation and osseointegration of the system took place rapidly, while recovery was precocious, comparable with traditional methods and with no severe complications.

LEVEL OF EVIDENCE

Case series, Level IV.

Is a synthetic augmentation in medial open wedge high tibial osteotomies superior to no augmentation in terms of bone-healing?

INTRODUCTION

Medial open-wedge high tibial osteotomy (MOWHTO) is an established method to treat unicompartimental osteoarthritis of the knee joint. However, augmentation of the created tibial gap after osteotomy is controversially discussed.

METHODS

We performed a prospective investigation of 49 consecutive cases of MOWHTO at our department. Patients were divided into two groups: group A consisted of 19 patients while group B consisted of 30 patients. In group A, the augmentation of the opening gap after osteotomy was filled with a synthetic bone graft, whereas group B received no augmentation. As an indicator for bone healing we investigated the non-union rate in our study population and compared the non-union-rate between the two groups.

RESULTS

The non-union rate was 28% in group A (five of 19 patients had to undergo revision) which received synthetic augmentation, while it was 3.3% in group B (one of 30 patients had to undergo revision) which received no augmentation. The difference between the groups was statistically significant (p-value 0.027).

CONCLUSIONS

With regard to bone healing after MOWHTO, synthetic augmentation was not superior to no augmentation in terms of non-union rates after surgery. In fact, we registered a significantly higher rate of non-union after augmentation with synthetic bone graft.

LEVEL OF EVIDENCE

III.

Is Bone Grafting Necessary in Opening Wedge High Tibial Osteotomy? A Meta-Analysis of Radiological Outcomes

Purpose

Bone grafting in opening wedge high tibial osteotomy (OWHTO) is still controversial. The purpose of this study is to compare the radiological outcomes of OWHTO with bone graft (autogenous, allogenous, and synthetic bone graft) and those without bone graft.

Materials and Methods

PubMed, MEDLINE, EMBASE and Cochrane Register of Studies databases were searched using specific inclusion and exclusion criteria for radiological studies involving OWHTO with bone graft and without bone graft groups. All reported delayed union, nonunion and correction loss were analyzed. Data were searched from the time period of January 2000 through July 2014. In addition, a modified Coleman methodology score (CMS) system was used to assess the methodological quality of the included studies.

Results

Twenty-five studies with a mean CMS value of 77 (range, 61 to 85 score) were included. In total, 1,841 patients underwent OWHTO using 4 different procedures for bone graft: autobone graft (n=352), allobone graft (n=547), synthetic bone graft (n=541) and no bone graft (n=401). There was a similar tendency for delayed union, nonunion and correction loss rate among the osteotomy space filling methods.

Conclusions

The meta-analysis showed there was a similar tendency for radiological union and correction maintenance among patients undergoing OWHTO regardless of the type of bone in all of the studies. However, the currently available evidence is not sufficient to strongly support the superiority of OWHTO with bone graft to OWHTO without bone graft.

Prospective 5-year survival rate data following open-wedge valgus high tibial osteotomy

PURPOSE

Open-wedge high tibial osteotomy using internal plate fixation is a well-established and frequently performed treatment option for the management of medial compartment osteoarthritis (OA) in the young and active patients. The present study provides survival rate and functional outcome preoperatively and after 6, 12, 24, 36 and 60 months following open-wedge high tibial osteotomy. Hypothesis of the authors was high survival rates after 5 years with still remaining satisfying functional results.

METHODS

Sixty-two patients suffering from tibial conditioned knee joint varus deformity and medial compartment OA that underwent high tibial osteotomy using an internal plate fixator (TomoFix™, Synthes) were included. Functional outcome was evaluated prior to surgery and in the further clinical course using standard instruments (IKDC score, Lysholm score). Treatment failure was defined as the need for total knee arthroplasty (TKA).

RESULTS

Fifty-one patients (mean age 46.8 ± 10.2 years) were available at a mean of 60.5 (SD ± 2.5) months (follow-up rate 82.3 %) postoperatively. Sixty-month IKDC (69.4 % SD ± 18.6) and Lysholm (76.6 SD ± 20.5) improved significantly when comparing with preoperative values (IKDC 44.6 SD ± 17.8; Lysholm 52.1 SD ± 20.8). Two of 51 subjects underwent TKA, resulting in a survival rate of 96 % among those patients followed (51 of 60; 85 %). Overall complication rate was 8.6 %.

CONCLUSION

With a survival rate of over 96 % at 5 years, high tibial osteotomy seems to be a reliable treatment option with satisfying clinical outcome. Functional outcome was stable following 60 months. While a delay of the necessity for TKA seems likely with regard to the survival rate demonstrated in this article, possible avoidance needs to be demonstrated by longer follow-up studies.

LEVEL OF EVIDENCE

Therapeutic case series, Level IV.

[Tibial valgization osteotomy by medial opening-wedge filled with cement for femorotibial 38 varus-valgus gonarthrosis]

Le genu varum sur gonarthrose fémorotibiale interne est une pathologie en nette recrudescence dans notre pays, affectant spécialement les femmes âgées et hautement invalidante chez l'adulte jeune; Souvent, elle pose un problème d'indication et de choix thérapeutique d'ordre multifactoriel. L'ostéotomie tibiale de valgisation par ouverture interne est une technique de référence, bien connue depuis longtemps et d'efficacité validée à court, moyen et long terme, et constitue un outil thérapeutique de choix et d'apport marqué, notamment pour les sujets jeunes actifs avec gonarthrose débutante. Par ailleurs, cette technique peut voir ses indications s’élargir au dépend de l’âge et du stade évolutif. Le but de notre travail est d’évaluer les résultats anatomiques et fonctionnels de notre technique d'ostéotomie tibiale de valgisation avec comblement cimenté chez l'adulte jeune de plus de 40 ans et de préciser les facteurs pronostiques qui régissent ces résultats. Ce travail propose à travers une étude rétrospectivement menée à propos de 38 genoux opérés chez 28 patients de dresser un bilan épidémiologique, clinique, et radiologique afin d’évaluer les résultats anatomiques et fonctionnels immédiats et à distance avec un recul minimum de 2 ans, de l'ostéotomie tibiale de valgisation avec comblement cimenté. Les 28 cas ont été revus à un recul moyen de 3,7 ans avec des extrêmes entre 2 et 9 ans, l’âge moyen de nos malades était de 52 ans avec des extrêmes de 40 à 67 ans, le sexe féminin était prédominant (64%). Le genu varum était primitif dans 20 cas (71,4%), et secondaire dans 8 cas (28,5%). Les stades I et II d'Ahlback constituaient la majorité des cas de l'arthrose fémoro-tibiale (94,7%). La déviation angulaire globale moyenne était de 11,3° avec des extrêmes de 8,5° à 18°. Les résultats évalués selon le protocole du groupe Guépar étaient excellents et très bons dans 86% des cas, et moyens et mauvais dans 14% des cas. Les meilleurs résultats ont été notés avec un âge au moment de l'ostéotomie de 60 ans, une arthrose au stade I et II d'Ahlback et un varus initial moyen ne dépassant pas 15°. La normocorrection a permis d'obtenir de bons résultats. Les complications postopératoires étaient rares sans conséquence sur les résultats thérapeutiques.

Bone grafts and bone substitutes for opening-wedge osteotomies of the knee: a systematic review

PURPOSE

To establish the rate of use of various void fillers in the setting of opening-wedge osteotomy around the knee, the types of fixation used, and the rates of delayed union or nonunion related to these variables. In addition, this review addressed short-term to midterm outcomes and complication rates associated with such procedures.

METHODS

The electronic databases Medline, Embase, and PubMed were searched using the methodology for systematic review as recommended by the Cochrane Collaboration. The search terms used were as follows: knee, osteotomy, knee joint, bone grafting, opening osteotomy, opening wedge, tibial osteotomy, femoral osteotomy, and bone substitute. We screened 1,383 articles and applied exclusion criteria. Fifty-six articles were included.

RESULTS

We included 3,033 cases of osteotomy in 2,910 patients. The mean age of patients was 50 years, with a mean follow-up period of 42 months. Male patients comprised 52% of patients. The mean alignment change was 10.8°, shifting the mechanical axis to 5.1° valgus. Delayed union/nonunion rates were 2.6%, 4.6%, and 4.5% for autograft, allograft bone, and synthetic bone substitutes, respectively (P = .03). Delayed union/nonunion rates were significantly lower for autograft compared with allograft (P = .03) and for autograft and allograft compared with synthetic bone substitutes (P < .0001). Non-locking plates (n = 2,148) had a rate of delayed union/nonunion of 3.7% and a mean loss of correction over time of 0.5°. Locking plates (n = 681) had a rate of delayed union/nonunion of 2.6% and a loss of correction of 2.3°. All mean knee outcome scores improved, and an overall complication rate of 14% was found.

CONCLUSIONS

Opening-wedge osteotomy had good short-term to midterm outcomes with acceptable complication rates. The lowest rates of delayed union/nonunion were in autograft bone-filled osteotomies. Plate type does not appear to affect osteotomy union or loss of correction.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I to IV studies.

Novel unidirectional porous hydroxyapatite used as a bone substitute for open wedge high tibial osteotomy

PURPOSE

The purpose of this study was to clinically and radiologically evaluate the availability, osteoconductivity, and resorption of a novel unidirectional porous hydroxyapatite (UDPHAp) used as an artificial substitute for open wedge high tibial osteotomy (OWHTO). Our hypothesis was that UDPHAp is a safe and useful bone substitute for OWHTO.

MATERIALS AND METHODS

Seven patients (2 men and 5 women aged 34-72years) who underwent OWHTO and were followed up for more than 12months were retrospectively studied. After the osteotomy, the gap created was filled with UDPHAp(REGENOS® Kuraray Co.Ltd). Radiography and computed tomography(CT) were performed, and gap healing was assessed postoperatively. The Japanese Orthopaedic Association (JOA) knee score was determined pre- and post-operatively for clinical evaluation.

RESULTS

Neither gross displacement nor collapse of the UDPHAp block graft was observed within 12 months after surgery. Both radiographs and CT showed attenuation of lucency and increasing sclerosis over time. JOA score improved from 71.2 (65-80) to 95.8 (85-100).

CONCLUSIONS

Short term results for OWHTO using UDPHAp was satisfactory. Clinical improvement of JOA scores were seen, besides osteogenesis was progressing in and around the artificial bone grafts.

High tibial osteotomy

High tibial osteotomy (HTO) is a widely accepted and performed procedure to treat medial knee arthrosis. The aim of this review is to evaluate the different surgical options in medial knee arthrosis, focusing on indications, patient's selection, long-term follow-up and survival analysis of HTO. Comparison and pooling of results are challenging because of different evaluation systems, small cohort number, and different surgical techniques. No differences have been described between opening and closing wedged HTO in terms of outcomes. Excellent early survivorship and good clinical outcomes were reported also with concomitant procedures. Correct indications, preoperative workup/planning, and technique selection are essential in achieving good results. The choice between opening and closing wedge osteotomy, graft selection in opening wedge HTO, comparison between HTO and unicompartmental knee arthroplasty, and the results of revised HTO to total knee replacement are currently under debate and will be discussed in the present review.

Utilizing reamer irrigator aspirator (RIA) autograft for opening wedge high tibial osteotomy: A new surgical technique and report of three cases

INTRODUCTION

The lateral closing wedge high tibial osteotomy (HTO) was popularized by Coventry in the 1960s. In the 1990s the medial opening wedge osteotomy gained popularity because it could achieve greater valgus correction and it did not require dissociation of the fibula from the tibia, an important consideration when treating varus knees with lateral and posterolateral ligament deficiencies (Noyes’ double-varus and triple-varus knees). However, it has the disadvantage of requiring bone graft to fill bony defects. Recently, the reamer-irrigator-aspirator (RIA; Synthes, Paoli, PA) system was developed, and as a result of this procedure, a large amount of usable autogenous bone graft can be collected safely for use. To our knowledge, there is no published series combining opening wedge HTO with the use of RIA obtained autogenous bone graft.

PRESENTATION OF CASE

We present a novel technique in which a series of three patients underwent opening wedge HTO using ipsilateral, retrograde femur RIA graft to fill the bone defect. All patients had satisfactory clinical and radiologic outcomes following the new technique at latest follow up.

DISCUSSION

Opening wedge high tibial osteotomy is a well-documented and accepted orthopedic procedure, however, has the disadvantage of requiring varying amounts of bone graft. Traditionally, iliac crest or tricortical allograft have been the grafting modalities of choice, however both have inherent drawbacks to their use. In our series, the use of RIA autograft is a safe and reliable harvest technique for high tibial osteotomy, providing abundant and quality autogenous bone graft.

CONCLUSION

All three of our patients achieved radiographic union with high clinical patient satisfaction without any major complications. We feel this novel technique is a safe and acceptable operative solution grafting opening wedge osteotomies about the knee.

The outcome of bone substitute wedges in medial opening high tibial osteotomy

BACKGROUND

Opening wedge high tibial osteotomy often requires bone grafting to improve the union rate and avoid instability at the osteotomy site. Autograft and allograft have both been associated with complications and the use of bone substitute wedges has been advocated to improve the outcome. This study investigated the clinical, radiological and histological outcomes of using biphasic calcium phosphate ceramic (Triosite) wedges in opening wedge high tibial osteotomy and determined whether the presence of the graft would compromise the satisfactory conversion to a total knee replacement.

METHODS

A consecutive cohort underwent radiological review to determine whether the osteotomy healed and the correction was maintained. Biopsies were performed on those undergoing second procedures. All patients converted to total knee arthroplasty were assessed separately as to any surgical complications attributed to the Triosite wedge.

RESULTS

There were 36 osteotomies in 33 patients with a minimum of 4 years follow up. All osteotomies healed. There was an average 90 (5-14) of correction, which was maintained. Histological assessment of 17 cases confirmed adequate bone replacement of the Triosite although some areas of tricalcium phosphate remained visible. Conversion to a total knee arthroplasty occurred in 11 cases with no complications.

CONCLUSION

Biphasic calcium phosphate ceramic wedges (Triosite) can be reliably used in opening wedge high tibial osteotomy with a low incidence of complications and satisfactory conversion to total knee arthroplasty.

Comparison between Autogenous Bone Graft and Allogenous Cancellous Bone Graft in Medial Open Wedge High Tibial Osteotomy with 2-Year Follow-up

PURPOSE

To compare the radiographic and clinical results of medial open wedge high tibial osteotomy (OWHTO) using autogenous bone graft and allogenous cancellous bone graft for medial compartment osteoarthritis of the knee with two-year follow-up.

MATERIALS AND METHODS

Fifty-one patients (52 knees) who underwent medial OWHTO from October 2007 to April. 2010 were included in the study. The patients were divided into group I (n=29) that received an autogenous tricortical bone graft and group II (n=23) that received an allogenous cancellous bone chip graft. The radiographic parameters (preoperative anatomical and mechanical femorotibial angles, modified tibial bone varus angle, and posterior tibial slope), clinical parameters, bone union period, and complications were evaluated from medical records.

RESULTS

The radiographic and clinical outcomes did not show significant difference between two groups. The average bone union period was 11.7 weeks in group I and 12.1 weeks in group II. The visual analog scale score on the first postoperative day was significantly higher in group I than group II.

CONCLUSIONS

Medial OWHTO using allogenous cancellous bone graft for medial compartment osteoarthritis of the knee can be considered as an alternative treatment method that provides equivalent radiographic and clinical results of OWHTO using autogenous bone graft and causes less immediate postoperative pain.

Safety of a novel high tibial osteotomy locked plate fixation for immediate full weight-bearing: a case-control study

PURPOSE

The safety and efficacy of the novel Limmed® system (locked plate fixation) for immediate full weight-bearing after medial opening wedge high tibial osteotomy (HTO) were evaluated in patients with symptomatic varus gonarthrosis.

METHODS

A case series of 85 consecutive osteotomies performed with Limmed® locked plate fixation for medial opening wedge HTO was compared to a historical matched case-control series of 85 HTOs (85 patients) performed using the same implant without locked screws. Subjects were observed at seven and 15 days and three, six and 12 months after surgery. Endpoints for evaluation included the reporting of adverse events, weight-bearing status without pain, radiographic evidence of bony union and changes in correction angle during healing.

RESULTS

Statistically significant differences were seen between groups in terms of safety (thrombophlebitis), time to weight-bearing, radiographic union and radiographic stability between the two groups. Patients of the Limmed® group reported less thrombophlebitis (one versus nine), outcome with shorter time for full weight-bearing (average 45 days difference, p = 0.01) and a shorter time for union (average four weeks difference). At the one-year follow-up the post-operative hip-knee-ankle angle was 4.2° of valgus in the Limmed® group and 2° of valgus in the control group. The adjusted mean difference of 2.2° was significant (p = 0.02) and related to loss of correction during healing in the control group with difference in implant stability. The severity of pain, knee score and walking ability improved in both groups with a significant difference before the third month (quicker for Limmed® group), while at the most recent follow-up only the difference for mobility in flexion was significant.

CONCLUSIONS

The Limmed® medial opening wedge HTO system represents a novel method of achieving a reliable correction while producing a stable fixation allowing satisfactory stability and bone healing with immediate full weight-bearing.

Gradual correction of idiopathic genu varum deformity using the Ilizarov technique

PURPOSE

Proximal tibial osteotomy is an effective treatment option for genu varum deformity among the many other described techniques. The purpose of this study is to evaluate the clinical and radiological outcomes and the complications in gradual correction of idiopathic genu varum deformity using Ilizarov frame.

METHODS

Proximal tibial medial opening wedge osteotomy was performed in 21 lower limbs of 11 patients, with whom the Ilizarov external fixator was used for gradual correction of the varus deformity. The mean age of the patients was 24.8 years (SD, 5.3). Deformity measurements of conventional mechanical axis deviation, mechanical medial proximal tibial angle, mechanical lateral distal femoral angle, posterior proximal tibial angle, joint conversion angle, tibio-femoral angle and tibial slope were compared.

RESULTS

The mean time for removal of the Ilizarov fixator was 24.7 weeks. At the last follow-up, the mean of Hospital for Special Surgery knee score increased, and the mean mechanical medial proximal tibial angle, tibio-femoral angle and conventional mechanical axis deviation improved. The differences between preoperative and postoperative posterior proximal tibial angle, mechanical lateral distal femoral angle, joint conversion angle and tibial slope were not significant. Ten complications were observed, of which 8 were minor complications and 2 were minor complications.

CONCLUSION

With a few complications, normal alignment and orientation of lower extremity can be established in patients with idiopathic genu varum deformity through gradual correction using a Ilizarov fixator.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

The effect of biplane medial opening wedge high tibial osteotomy on patellofemoral joint indices

PURPOSE

This study was designed to examine the effect of biplane medial opening wedge high tibial osteotomy (MOWHTO) on patellofemoral indices and posterior tibial slope.

MATERIALS AND METHODS

Sixty-two knees (61 patients) underwent biplane MOWHTO for unicompartmental osteoarthritis of the knee. Patellar indices were measured by radiographic assessment postoperatively. The Merchant's views were used for patellar tilt and shift while standing lateral view radiographs were used for the patellar height analysis using the modified Blackburne-peel ratio (mBP). The patients were divided into two groups according to the change between the pre- and postoperative mechanical axis. Group A constituted the correction angle of equal more than 10°, and group B of less than 10°.

RESULTS

Group A demonstrated a significant change of mechanical axis and the tibial slope. Patellar indices including the patellar tilt, shift, and mBP did not show significant difference. Group B demonstrated the statistical significant difference in only the mechanical axis deviation. Patellar indices including the patellar tilt, shift, and mBP as well as the tibia slope did not show significant difference. When evaluated as a whole group, the mean shift in weight bearing line, patellar height (mBP), and tibial slope from preoperative to postoperative value was statistically significant. However, the patellar tilt and shift were not changed significantly.

CONCLUSIONS

After biplane MOWHTO, patellar tilt and shift do not significantly change when measured on static mode supine X-ray. However, patella was lowered and tibia slope increased after MOWHTO.

LEVEL OF EVIDENCE

II.

Bovine xenograft locking Puddu plate versus tricalcium phosphate spacer non-locking Puddu plate in opening-wedge high tibial osteotomy: a prospective double-cohort study

PURPOSE

The aim of the study was to compare clinical and radiographic outcomes of opening-wedge high tibial osteotomy (HTO) augmented with either xenograft or tricalcium phosphate spacer for the management of medial compartment osteoarthritis (OA) with genu varum.

METHODS

Between 2004 and 2007, we prospectively enrolled 52 patients with medial compartment knee OA who underwent opening-wedge HTO fixed with locking Puddu plate and xenograft (n = 26) or non-locking Puddu plate and tricalcium phosphate spacer (n = 26). The alignment of the lower limb was assessed by measuring the hip-knee-ankle (HKA) angle. Clinical outcomes were assessed with the Knee Society Score, Western Ontario and McMaster Universities Osteoarthritis Index, SF-36 and European Quality of Life-5 Dimensions scale. All patients were followed up at six weeks and at three, six, 12 and 24 months post-operatively. Clinical outcomes were assessed preoperatively and at 24 months post-operatively.

RESULTS

All clinical scores improved significantly in both groups after surgery, without any significant difference between the two groups. Immediately after surgery, the HKA angle went from 9.1 ± 5.2° in varus to 3.1 ± 4.8° in valgus (P = 0.01) in the xenograft group, and from 8.5 ± 5.9° in varus to 3.4 ± 4.2° in valgus (P = 0.01) in the tricalcium phosphate group. At the last follow-up, the tricalcium phosphate group showed a significant loss of correction (P = 0.03).

CONCLUSIONS

HTO performed with xenograft locking plate and tricalcium phosphate non-locking plate constructs showed good clinical outcomes. However, the xenograft locking plate construct is superior to the tricalcium phosphate spacer non-locking plate to prevent the loss of correction in the middle term.

The impact of a high tibial valgus osteotomy and unicondylar medial arthroplasty on the treatment for knee osteoarthritis: a meta-analysis

PURPOSE

Both high tibial valgus osteotomy (HTO) and unicompartmental medial knee arthroplasty (UKA) are established methods for the treatment for moderate stages of OA. This is the first global meta-analysis to compare the long-term effects of both methods regarding survival, outcomes and complications of total arthroplasty.

METHODS

Literature research was performed using established medical databases: MEDLINE (via PubMed), EMBASE (via OVID) and the Cochrane register. Criteria for inclusion were as follows: English or German papers, a clinical trial with a clear description of survival, an outcome evaluation using a well-described knee score and a follow-up >5 years. Statistical analysis was performed using the special meta-analysis software called "Comprehensive Meta Analysis" (version 2.0; Biostat, Englewood, NJ, USA).

RESULTS

Final meta-analysis after the full-text review included 46 studies about valgus HTO and 43 studies about medial UKA. There were no significant differences between valgus HTO and medial UKA in terms of the number of total required replacements. After a 5- to 8-year follow-up, 91.0% of the valgus HTO patients and 91.5% of medial UKA patients did not need a total replacement. This value was 84.4% for valgus HTOs and 86.9% for medial UKAs after a 9- to 12-year follow-up. Mean survival time to TKA was 9.7 years after valgus HTO and 9.2 years after medial UKA. Clinical outcome was significantly better after medial UKA in a 5- to 12-year follow-up. After more than 12 years, results were comparable in both groups. No significant differences were seen in the complication rates.

CONCLUSIONS

This meta-analysis aimed to find the advantages and disadvantages of two established methods for the treatment for medial compartment knee osteoarthritis. Valgus HTO is more appropriate for younger patients who accept a slight decrease in their physical activity. Medial UKA is appropriate for older patients obtaining sufficient pain relief but with reduced physical activity.

LEVEL OF EVIDENCE

II.

Patellar height modification after high tibial osteotomy by either medial opening-wedge or lateral closing-wedge osteotomies

PURPOSE

High valgus tibial osteotomy is used to treat medial femoro-tibial osteoarthritis. Changes in patellar height due to high valgus tibial osteotomy can cause technical difficulties during subsequent knee arthroplasty. The primary objective of this study was to assess the hypothesis that patellar height decreases after opening-wedge osteotomy and increases after closing-wedge osteotomy. The secondary objective was to assess whether frontal axis correction and tibial slope modification correlated with patellar height changes.

METHODS

A multicentre, prospective, comparative, observational, non-randomised study was conducted in consecutive patients undergoing isolated high valgus tibial osteotomy according to standard practice in each of the ten study centres. Patellar height was assessed based on the Caton-Deschamps index.

RESULTS

Of 321 included patients, 224 underwent opening-wedge and 97 closing-wedge osteotomy. Patellar height did not change significantly after closing-wedge osteotomy (1.07 ± 0.2 pre-operatively and 1.0 ± 0.19 postoperatively). Patellar height decreased significantly after opening-wedge osteotomy (from 0.98 ± 0.19 to 0.88 ± 0.21, p < 0.0001, mean decrease 9 ± 22%). Patellar height decreased by more than 20% in 49 (28%) patients after opening-wedge osteotomy. The patellar height decrease after opening-wedge osteotomy correlated significantly with axis correction magnitude and tibial slope change.

CONCLUSION

Our results support routine baseline measurement of patellar height before high valgus tibial osteotomy and posterior positioning of the opening wedge to limit the tibial slope change in patients requiring major axis correction by opening-wedge osteotomy.

LEVEL OF EVIDENCE

Prospective cohort study, Level II.

High complication rate after biplanar open wedge high tibial osteotomy stabilized with a new spacer plate (Position HTO plate) without bone substitute

PURPOSE

We performed a prospective clinical and radiographic evaluation after open wedge high tibial osteotomy (HTO) using the new Position HTO plate (Aesculap, Tuttlingen, Germany) without bone transplantation.

METHODS

Thirty-five open wedge HTOs with the Position HTO plate were performed without bone wedges. The mean patient age was 44.6 ± 9.2 years at the time of osteotomy, which was planned with mediCAD II software (Hectec, Niederviehbach, Germany). The Hospital for Special Surgery score, Lysholm-Gillquist score, Tegner activity level, and International Knee Documentation Committee subjective score were used for clinical assessment. We evaluated radiographs obtained preoperatively and at 2, 6, and 12 months postoperatively using full-weight-bearing anteroposterior whole-leg views and anteroposterior and lateral views of the knee. For statistical analyses, JMP 8.0.1 (SAS, Cary, NC) was used.

RESULTS

We observed an overall complication rate of 34% and a plate-related complication rate of 23%. Plate-related complications included loss of correction, fracture of the tibial plateau, screw failure, malunion, and fracture of the lateral cortical bone. A significant difference in the mechanical tibiofemoral angle of -1.3° ± 1.4° (P < .001) was found between the follow-up at 2 and 6 months. The mean Hospital for Special Surgery score was 74.8 ± 11.7 preoperatively, and it increased to 87.8 ± 11.0 (P < .001). The mean score on the Lysholm-Gillquist knee functional scoring scale was 55.5 ± 21.7 preoperatively, and it improved to 73.0 ± 23.9 (P < .001). The Tegner activity level was 2.6 ± 0.9 preoperatively, and it improved significantly at final follow-up to 3.7 ± 1.8 (P < .02). The International Knee Documentation Committee subjective score was 43.0 ± 14.9 preoperatively, and it increased to 66.1 ± 21 (P < .001).

CONCLUSIONS

We have shown a high plate-related complication rate and a significant loss of correction between 2 and 6 months of follow-up after open wedge HTO using the new Position HTO plate without bone wedges. The preoperatively planned mechanical tibiofemoral angle was not achieved. Despite these complications, the clinical outcome improved significantly. The Position HTO plate cannot be recommended with the presented technique.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.