Postoperative Femorotibial Angle Research Articles

Impact of postoperative femorotibial axis on functional outcomes in unicompartmental knee arthroplasty.

This study aimed to compare the functional outcomes of patients undergoing fixed-bearing medial unicompartmental knee arthroplasty (UKA) classified as either varus or neutral based on their postoperative femorotibial angle (FTA), with the goal of evaluating the impact of FTA on functional results. A total of 38 knees of 35 patients (27 females, 8 males; mean age: 63.6±7.1 years; range, 52 to 75 years) were included in this retrospective study. The data was collected between December 15, 2020, and January 15, 2021. Patients were categorized into two groups based on their postoperative FTA. The neutral group consisted of patients with an FTA range of 5.1° to 7.4°, while the varus group included patients with an FTA range of 0.1° to 4.8°. Knee Outcome Osteoarthritis Score (KOOS), Visual Analog Scale (VAS) scores, sit to stand test results, and six minute walk test data were analyzed. The mean follow-up was 42.0±19.3 months. The postoperative VAS score for the varus group was 0.95±0.99, whereas the neutral group had a VAS score of 2.19±1.83 (p=0.021). The mean KOOS for the varus group was 88.01±7.88, whereas the neutral group had a mean KOOS score of 78.46±13.69 (p=0.006). In patients undergoing UKA, mild varus alignment could yield superior early and midterm functional outcomes compared to a neutral femorotibial angle.

Observation on Curative Effect of Minimally Invasive Osteotomy Combined with Ilizarov Technique in the Treatment of Knee Osteoarthritis with Varus Deformity

This paper aims to analyze the clinical efficacy of minimally invasive osteotomy combined with Ilizarov technique in the treatment of knee osteoarthritis with varus deformity. 80 patients with knee osteoarthritis and varus deformity who were treated in our hospital from January 2022 to May 2023 were selected, all of whom were affected by one knee. They were randomly divided into groups, including the study group and the control group, each with 40 patients. Patients in the control group were treated with fibula-tibial osteotomy and internal fixation, and patients in the study group were treated with minimally invasive osteotomy combined with Ilizarov technique. The operation time of the patients in the study group was significantly longer than that of the control group (P < 0.05). The intraoperative blood loss of the patients in the study group was significantly more than that of the control group (P < 0.05). The hospitalization expenses of the patients in the study group were significantly more than those of the control group (P < 0.05). The postoperative femorotibial angle and mechanical axis offset distance in the study group were significantly smaller than those in the control group (P < 0.05). The postoperative New York Hospital for Special Surgery (HSS) scores of the study group were significantly higher than those of the control group (P < 0.05). The postoperative visual analogue scale (VAS) score of the study group was significantly lower than that of the control group (P < 0.05). The range of motion of the knee joint in the study group was significantly greater than that in the control group (P < 0.05). The incidence of tendon injury, infection, and nerve injury in the study group (2.50%) was significantly lower than that in the control group (30.00%) (P < 0.05). Minimally invasive osteotomy combined with Ilizarov technique can be applied in the treatment of knee osteoarthritis with varus deformity, although the operation time is longer, with more intraoperative blood loss and higher treatment cost, but it has no effect on the femorotibial angle and mechanical axis deviation of the patient. It can significantly improve the movement distance, knee joint function, and knee joint range of motion, and significantly reduce the postoperative pain of patients, reduce the incidence of complications, and thus has high clinical application value.

Using short knee radiographs to predict the coronal alignment after TKA: Is it an accurate proxy for HKA on full-length images?

BackgroundThe postoperative clinical outcomes has been extensively demonstrated to correlate with the coronal alignment after total knee arthroplasty (TKA). However, in different studies, either the hip-knee-ankle angle (HKA) on a full-length radiograph or the femorotibial angle (FTA) on a short knee film was used to categorize the postoperative coronal alignment. Meanwhile, several different FTA ranges were regarded as neutral alignment in different studies. As a result, it is still unknown that how FTA on short knee films and HKA related to each other. The FTA may be able to become an accurate proxy of HKA to predict the coronal alignment. The purpose of this study was to explore the correlation between the FTA and the HKA after TKA and to find the most accurate FTA range.MethodsAbout 223 patients were included in this study and standard weight-bearing short knee films as well as full-length radiographs were acquired. The pre- and postoperative FTA, as well as the postoperative anatomical lateral distal femoral angle (aLDFA) and anatomical medial proximal tibial angle (aMPTA) were measured on short knee films by two orthopedic surgeons independently. On full-length films, the pre- and postoperative FTA, the pre- and postoperative HKA, as well as the postoperative mechanical lateral distal femoral angle (mLDFA) and mechanical medial proximal tibial angle (mMPTA) were also recorded by two other surgeons independently. Pearson correlation analysis was performed to compare FTA and HKA, aMTPA and mMTPA, aLDFA and mLDFA, respectively.ResultsThe postoperative FTA and HKA had a good correlation (r = 0.86). The agreements were reached 82.7%, 71.0%, and 68.2% of all patients using three previously reported FTA ranges. When analyzing the independent alignment of the tibial tray and the femoral component, 84.1% and 57.9% of all patients was reached an agreement on the classification.ConclusionsOn most occasions, the consistence between the FTA and HKA in assessing the coronal limb alignment of the lower extremity and the tibial component is satisfactory. However, the postoperative full-length film is still needed to evaluate accurately the coronal alignment of the femoral component.

Evaluation of postoperative orientation of the knee and ankle joint after open wedge high tibial osteotomy

BackgroundCases with varus knee osteoarthritis (OA) often present concomitant ankle joint deformity and poor tibial plafond inclination (TPI) in the coronal plane. Although changes to the TPI with respect to the ground after open wedge high tibial osteotomy (OWHTO) have been described, reports on the relationship between the correction angle and severity of knee joint line obliquity (KJLO) are scarce. This study aimed to examine the correlation between the correction angle after OWHTO and the change in knee and ankle inclination with respect to the floor. MethodsBetween January 2016 and December 2019, 39 knees in 39 patients (mean age, 58.3 ± 9.7 years; male, 14 knees; female, 25 knees) underwent OWHTO for varus knee OA. The mean duration of follow up was 30.1 ± 9.8 months. Radiological severity of OA was evaluated for those with Kellgren-Lawrence grade 1–3. Preoperative and 1-year postoperative radiographs were used to examine the postoperative femorotibial angle, hip-knee angle, KJLO, TPI, talar tilt (TT), position of weight bearing line of the tibial plateau width (WBL ratio; %), and the relationship between the pre-to postoperative changes in each measured value and intraoperative correction angle. The relationship between the pre-to postoperative changes in each measured value and intraoperative correction angle were evaluated. Clinical evaluations were conducted before and 2 years after OWHTO using the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale of pain. ResultsThe mean pre-to post-operative changes were 3.2 ± 2.2 for KJLO and 3.1 ± 2.5 for TPI, both demonstrating significant differences as well as significant correlations with the correction angle. The knee joint demonstrated postoperative changes in the valgus direction and none in the varus direction with respect to the floor in all cases. Furthermore, the sum of changes to the KJLO and TPI showed a positive correlation that approximates the change in the correction angle. The mean pre- and postoperative 2-year KOOS subscale of pain were 50.2 ± 10.2 and 82.3 ± 9.1. There were no correlations between preoperative TPI, pre-to postoperative change in TPI, and 2-year postoperative of KOOS subscale of pain. ConclusionFor those who underwent OWHTO for varus OA, the knee joint changed from a preoperative varus malalignment to mild valgus malalignment, and the ankle joint tended to improve from a preoperative valgus malalignment to the postoperative neutral alignment with respect to the floor. Although a positive correlation was found in which the correction angle approximates the sum of changes to the KJLO and TPI, no significant difference was found between changes in KJLO and TPI nor in the ratio between the correction angle and changes in each measured value.

The Role of Prophylactic Peroneal Nerve Decompression in Patients with Severe Valgus Deformity at the Time of Primary Total Knee Arthroplasty.

BackgroundCommon peroneal nerve (PN) palsy after total knee arthroplasty (TKA) is a serious complication. Although many authors suggest delayed or immediate PN decompression after TKA in these patients, little is known about the role of prophylactic peroneal nerve decompression (PPND) at the time of TKA. The aim is to report the results of PPND in high-risk patients at the time of TKA.Materials and methodsA multi-institutional retrospective study review of nine patients (10 knees) who underwent PPND at the time of TKA was conducted. Patients who had severe valgus deformities (≥15° of femorotibial angle and not fully correctable by examination under anaesthesia) with or without flexion contractures were included. PPND was performed through a separate 3–4-cm incision at the time of TKA. The demographics, preoperative and postoperative anatomical and mechanical alignments, range of motion, operation time, postoperative neurological function and complications were recorded.ResultsAll patients had a completely normal motor and sensory neurological function postoperatively and no complications related to PPND were reported. All patients followed the standard physical therapy protocol after TKA without modifications.The mean preoperative femorotibial angle was 20° (range 15–33°) and the mean postoperative femorotibial angle was 6.3° (range 5–9°) (p = 0.005). The mean preoperative flexion contracture was 9 (range 0–20) and the mean residual contracture was 1.2° (range 2–5°) (p = 0.006).ConclusionPPND at the time of TKA is an option to minimise the risk of PN palsy in high-risk patients. This approach can be considered for patients undergoing TKA in selected high-risk patients with a severe valgus deformity.How to cite this articleMakhdom A, Hamilton AA, Rozbruch SR. The Role of Prophylactic Peroneal Nerve Decompression in Patients with Severe Valgus Deformity at the Time of Primary Total Knee Arthroplasty. Strategies Trauma Limb Reconstr 2022;17(1):38–43.

Proximal Tibiofibular Dislocation in Closing-Wedge High Tibial Osteotomy Increases the Risk of Medium and Long-Term Total Knee Replacement.

Proximal tibiofibular dislocation in closing-wedge high tibial osteotomy increases the risk of medium and long-term total knee replacement. Background: High tibial osteotomy is an effective treatment for medial osteoarthritis in young patients with varus knee. The lateral closing-wedge high tibial osteotomy (CWHTO) may be managed with tibiofibular dislocation (TFJD) or a fibular head osteotomy (FHO). TFJD may lead to lateral knee instability and thereby affect mid- and long-term outcomes. It also brings the osteotomy survival rate down. Objective: To compare the CWHTO survival rate in function of tibiofibular joint management with TFJD or FHO, and to determine whether medium and long-term clinical outcomes are different between the two procedures. Material & Methods: A retrospective cohort study was carried out that included CWHTO performed between January 2005 to December 2018. Those patients were placed in either group 1 (FHO) or Group 2 (TFJD). Full-leg weight-bearing radiographs were studied preoperatively, one year after surgery and at final follow-up to assess the femorotibial angle (FTA). The Rosenberg view was used to assess the Ahlbäck grade. The Knee Society Score (KSS) was used to assess clinical outcomes and a Likert scale for patient satisfaction. The total knee replacement (TKR) was considered the end of the follow-up and the point was to analyze the CWHTO survival rate. A sub-analysis of both cohorts was performed in patients who had not been FTA overcorrected after surgery (postoperative FTA ≤ 180°, continuous loading in varus). Results: A total of 230 knees were analyzed. The follow-up period ranged from 24–180 months. Group 1 (FHO) consisted of 105 knees and group 2 (TFJD) had 125. No preoperative differences were observed in terms of age, gender, the KSS, FTA or the Ahlbäck scale; neither were there any differences relative to postop complications. The final follow-up FTA was 178.7° (SD 4.9) in group 1 and 179.5° (SD 4.2) in group 2 (p = 0.11). The Ahlbäck was 2.21 (SD 0.5) in group 1 and 2.55 (SD 0.5) in group 2 (p = 0.02) at the final follow-up. The final KSS knee values were similar for group 1 (86.5 ± 15.9) and group 2 (84.3 ± 15.8). Although a non-significant trend of decreased HTO survival in the TFJD group was found (p = 0.06) in the sub-analysis of non-overcorrected knees, which consisted of 52 patients from group 1 (FHO) and 58 from group 2 (TFJD), 12.8% of the patients required TKR with a mean of 88.8 months in group 1 compared to 26.8% with a mean of 54.9 months in the case of group 2 (p = 0.005). However, there were no differences in clinical and radiological outcomes. Conclusion: TFJD associated with CWHTO shows an increase in the conversion to TKR at medium and long-term follow-up with lower osteotomy survival than the CWHTO associated with FHO, especially in patients with a postoperative FTA ≤ 180° (non-overcorrected). There were no differences in clinical, radiological or satisfaction results in patients who did not require TKR. Level of evidence III. Retrospective cohort study.

Difference in the early postoperative change of the joint line convergence angle between opening wedge and closed wedge high tibial osteotomies

BackgroundThe purpose of this study was to investigate the correction error associated with soft tissue balance in high tibial osteotomy (HTO) and the difference between opening wedge HTO (OWHTO) and closed wedge HTO (CWHTO).MethodsA total of 170 knees of 130 patients (85 knees of 68 patients in OWHTO and 85 knees of 62 patients in CWHTO) were evaluated. Anteroposterior radiographs of the knee and full-length leg were taken preoperatively, immediately under general anesthesia postoperatively, 2 days, and 1 and 12 months postoperatively. The femorotibial angle (FTA), joint line convergence angle (JLCA), and medial proximal tibial angle (MPTA) were measured.ResultsThe postoperative FTA was decreased from 170.5 ± 2.1° at 0 day to 168.6 ± 2.2° at 2 days in OWHTO (P < 0.05), whereas it was not changed from 168.7 ± 2.4° at 0 day to 168.1 ± 2.8° at 2 days in CWHTO. The JLCA was 4.8 ± 1.8° preoperatively, 4.2 ± 1.9° at 0 day, 2.2 ± 1.8° at 2 days (P < 0.05 vs 0 day), 2.6 ± 1.7° at 1 month, and 2.7 ± 1.6° at 12 months in OWHTO, and 7.1 ± 3.2° preoperatively, 4.1 ± 2.4° at 0 day (P < 0.05 vs preoperative), 3.4 ± 2.5° at 2 days, 3.9 ± 2.3° at 1 month, and 4.2 ± 2.6° at 12 months in CWHTO. Multiple regression analysis showed that preoperative factors affecting change of the JLCA from preoperative to postoperative 1 month were the correction angle in OWHTO (P = 0.001) and the preoperative standing JLCA in OWHTO (P < 0.001) and CWHTO (P < 0.001).ConclusionsA significant decrease of the JLCA occurred immediately after osteotomy under anesthesia in CWHTO, whereas in OWHTO there was no decrease under anesthesia, but it decreased several days postoperatively.

Lateral epicondyle osteotomy for correction of valgus deformity during total knee arthroplasty: Surgical technique and clinical outcomes

BackgroundLateral epicondyle osteotomy is one of the surgical choices when seeking a proper equalization and balance of the flexion and extension gaps during the correction of a valgus knee deformity, when performing a total knee arthroplasty (TKA). However, its use is not frequent, and the reports described in literature are scarce. The aim of this study was to describe the clinical outcomes of the patients in which lateral epicondyle osteotomy was performed during TKA in a consecutive group of patients with valgus deformity. MethodsRetrospective study of 18 patients with valgus deformity, who had lateral epicondyle osteotomy during TKA, from January 2016 to December 2018. The type of valgus deformity was assessed with Ranawat’s classification. The femorotibial angle was measured with a panoramic leg standing X-rays before and after the TKA; The function was evaluated with the Knee Society Score-KSS and Oxford Knee Score scale. ResultsThe average age was 71.8 ± 6.1 years and 13 cases were women. According to Ranawat’s classification, 11 knees had Grade III (>20°) valgus deformity. The mean preoperative and postoperative femorotibial angles were 25.8° ± 9.9° and 7.1° ± 1.8°, respectively. Functional improvement was observed through the KSS and Oxford scales, with an average increase of 37.4 ± 13.4 and 32.4 ± 6.7 points compared to preoperative. No evidence of intraoperative or postoperative complications associated with the procedure was found. ConclusionIn these patients, the osteotomy of the lateral epicondyle proved to be an effective surgical option for the correction of valgus deformity during TKA, allowing proper alignment of the limb with good functional results.

Correlation between the preoperative Kellgren-Lawrence grade and the clinical outcome of mid-term to long-term follow-up in high tibial osteotomy

Correlation between the preoperative Kellgren-Lawrence grade and the clinical outcome of mid-term to long-term follow-up in high tibial osteotomy

Severe varus knees result in a high rate of undercorrection of lower limb alignment after opening wedge high tibial osteotomy.

The purpose of this study was to clarify the indication for opening wedge high tibial osteotomy (OWHTO) in terms of lower limb alignment to achieve satisfactory clinical results. Ninety-two patients (98 knees) with medial compartment knee osteoarthritis were investigated in this study. The average follow-up period was 34 months (range, 24-68 months). The average age of the patients at the time of surgery was 63 years (range, 41-77 years). The patients were divided into the following two groups according to the preoperative femorotibial angle (FTA) on anteroposterior full-length radiographs of the lower limbs while weight bearing: 29 knees with a preoperative FTA of ≥185° were defined as those with severe varus (S group), and the remaining 69 knees with a preoperative FTA of <185° were defined as those with mild varus (M group). Knees with a postoperative FTA of >175° were defined as undercorrected. The Lysholm score was used to assess the clinical results. The average postoperative FTA was 175.7° ± 4.1° in the S group and 174.6° ± 3.1° in the M group ( p = 0.013). Significantly, more undercorrected knees were observed in the S than M group ( p = 0.00035). The postoperative Lysholm score was 85.6 ± 8.5 in the S group and 88.5 ± 5.7 in the M group at the last follow-up ( p = 0.0033). Based on these results, we recommend that a preoperative FTA of <185° should be included as a criterion for OWHTO alone.

Correlation of medial compartmental joint line elevation with femorotibial angle correction and clinical function after unicompartmental arthroplasty

To study the correlation of postoperative femorotibial angle with medial compartmental joint line elevation after unicompartmental arthroplasty(UKA), as well as the correlation of joint line elevation with the clinical function by measuring radiological joint line. A retrospective study of 56 patients from July 2012 to August 2015 was performed. The mean body mass index (BMI) was 23.5 (ranged, 18.3 to 30.1). The standing anteroposterior radiographs of these patients were assessed both pre-and post-operatively, and the knee function was evaluated according to HSS grading. The correlation between postoperative femorotibial angle(FTA) and joint line elevation was analyzed as well as the correlation between joint line elevation and the clinical function. The mean medial joint line elevation was (2.2±2.0) mm(ranged, -3.3 to 7.0 mm), and the mean FTA correction was (2.3±3.0)°(ranged, -4.5° to 9.6°). The mean follow-up period was 12.2 months. There was a significant correlation between in joint line elevation and FTA correction(P<0.05), while there was no significant correlation between joint line elevation and the clinical function(P>0.05). There was a significant correlation between medial compartmental joint line elevation and FTA correction after UKA, and the proximal tibial osteotomy was critical during the procedure. There was no significant correlation between joint line elevation and the clinical function, which may be related to the design of UKA prosthesis.

Effectiveness of distal femoral osteotomy assisted by three-dimensional printing technology for correction of valgus knee with osteoarthritis

To evaluate the effectiveness of distal femoral osteotomy aided by three-dimensional (3D) printing cutting block for correction of vaglus knee with osteoarthritis. Between January 2014 and January 2016, 12 patients (15 knees) with vaglus deformity and lateral osteoarhritis underwent medial closing wedge distal femoral osteotomy. There were 5 males and 7 females, aged 30-60 years (mean, 43.8 years). The mean disease duration was 6.6 years (range, 1-12 years). The unilateral knee was involved in 9 cases and bilateral knees in 3 cases. According to Koshino's staging system, 1 knee was classified as stage I, 9 knees as stage II, and 5 knees as stage III. The X-ray films of bilateral lower extremities showed that the femorotibial angle (FTA) and anatomical lateral distal femoral angle (aLDFA) were (160.40±2.69)° and (64.20±2.11)° respectively. Mimics software was used to design and print the cutting block by 3D printing technique. During operation, the best location of distal femoral osteotomy was determined according to the cutting block. After osteotomy, internal fixation was performed using a steel plate and screws. All incisions healed primarily; no complication of infection or deep vein thrombosis was observed. All patients were followed up 6-18 month (mean, 12.2 months). At 6 months after operation, the hospital for special surgery (HSS) score for knee was significantly improved to 89.07±2.49 when compared with preoperative score (65.27±1.49, t=-28.31, P=0.00); the results were excellent in 10 knees, good in 4 knees, and fair in 1 knee with an excellent and good rate of 93.3%. The bony union time was 2.9-4.8 months (mean, 3.3 months). Bone delayed union occurred in 1 case (1 knee). The postoperative FTA and aLDFA were (174.00±1.41)° and (81.87±1.06)° respectively, showing significant differences when compared with preoperative ones ( t=-18.26， P=0.00; t=-25.19, P=0.00). The percentage of medial tibial plateau in whole tibial plateau was 49.78%±0.59%, showing no significant difference when compared with intraoperative measurement (49.82%±0.77%, t=0.14, P=0.89). 3D printing cutting block can greatly improve the accuracy of distal femoral osteotomy, and ensure better effectiveness for correction of vaglus knee with osteoarthritis.

Clinical Outcomes of Patients with Valgus Deformity Undergoing Minimally Invasive Total Knee Arthroplasty Through the Medial Approach.

Objective: The purpose of this study was to compare the clinical outcomes between patients with a valgus or varus deformity undergoing minimally invasive total knee arthroplasty through the medial approach.Methods:The patients were classified into 2 groups according to the preoperative femorotibial angle measured on an anteroposterior long leg roentgenogram. The valgus group comprised of 26 knees in 21 patients with a femorotibial angle <170° (163.5 ± 5.7), and the varus group comprised of 24 knees in 21 patients with a femorotibial angle >190° (195.9 ± 5.5). The following background variables were compared between the groups: age at the time of the operation, sex, causative disease, preoperative femoral mechanical–anatomical angle, and postoperative knee range of motion, Knee Society score, femorotibial angle, and implant position.Results:There were significant differences between the valgus and varus groups in the age (68.0 ± 6.9 vs 75.8 ± 6.2 years), percentage of males (23.8% vs 0%), percentage with rheumatoid arthritis (61.9% vs 4.8%), and preoperative femoral mechanical–anatomical angle (6.2 ± 1.0° vs 7.4 ± 2.1°). Clinical outcome variables of postoperative femorotibial angle (173.1 ± 3.9° vs 175.2 ± 1.6°) and α angle (96.6 ± 3.1° vs 95.0 ± 1.9°) also differed.Conclusion:It was assumed that over-valgus resection of the femur is a contributory factor to residual valgus alignment. However, knee range of motion and Knee Society score did not differ between the groups. We suggest that minimally invasive total knee arthroplasty through the medial approach is one of the treatment options for patients with valgus deformity.

Does final component alignment correlate with alignment of the bone resection surfaces in cemented total knee arthroplasty?

To examine, with a navigation, whether the final component alignments correlate with alignment of the bone resection surfaces in cemented total knee arthroplasty (TKA), and to evaluate the factors affecting alignment deviation. A total of 222 patients (276 knees) who underwent navigation-assisted TKA between September 2012 and January 2014 due to osteoarthritis were retrospectively reviewed. The deviation between the alignment of bone resection surfaces and the final alignment of femoral and tibial components was measured. Factors associated with alignment deviation of greater than 2° (outliers) were evaluated. These included age, sex, body mass index, bone mineral density (T score), preoperative and postoperative mechanical femorotibial angle, preoperative and postoperative flexion contractures, and the difference between medial and lateral gaps in knee extension or flexion. Outliers consisted of 24 cases (8.6%) on the femoral coronal plane, 4 cases (1.4%) on the tibial coronal plane, and 48 cases (17.4%) on the tibial sagittal plane. In the coronal plane (femur and tibia), the outliers were associated with preoperative [p<0.001; odds ratio (OR) 0.774; 95% confidence interval (CI) 0.672-0.891] and postoperative (p<0.001; OR 0.240; 95% CI 0.123-0.468) flexion contractures; a difference of 3mm or more between the medial and lateral gaps in knee extension (p<0.041; OR 5.805; 95% CI 1.075-31.343); and a T score of less than -2.5(p<0.024; OR 5.899; 95% CI 1.258-27.664). In the sagittal plane of the tibia, the outliers were associated with preoperative (p<0.001; OR 0.886; 95% CI 0.829-0.946) and postoperative (p<0.031; OR 0.803; 95% CI 0.659-0.980) flexion contractures. There was a deviation between the alignments of the bone resection surfaces and the final alignments of components. With larger preoperative and postoperative flexion contractures in the coronal and sagittal planes, there were more outlier risks. The outliers in the coronal plane were associated with a difference of 3mm or more between the medial and lateral gaps in knee extension and poor bone quality. Awareness of such alignment deviation and related factors can help diminish the outliers after TKA. IV.

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

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. 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 2years postoperatively. Mean postoperative FTAs were 168.5° in the navigated group and 168.1° inthe 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). 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. Thenavigation system in OWHTO was helpful for simultaneous control of the alignment in 2 planes. Level II, lesser-quality prospective randomized trial.

Mid-term survival analysis of closed wedge high tibial osteotomy: A comparative study of computer-assisted and conventional techniques

BackgroundThe purpose of the present study was to compare the clinical and radiographic results and survival rates between computer-assisted and conventional closing wedge high tibial osteotomies (HTOs). MethodsData from a consecutive cohort comprised of 75 computer-assisted HTOs and 75 conventional HTOs were retrospectively reviewed. The Knee Society knee and function scores, Hospital for Special Surgery (HSS) score and femorotibial angle (FTA) were compared between the two groups. Survival rates were also compared with procedure failure. ResultsThe knee and function scores at one year postoperatively were slightly better in the computer-assisted group than those in conventional group (90.1 vs. 86.1) (82.0 vs. 76.0). The HSS scores at one year postoperatively were slightly better for the computer-assisted HTOs than those of conventional HTOs (89.5 vs. 81.8). The inlier of the postoperative FTA was wider in the computer-assisted group than that in the conventional HTO group (88.0% vs. 58.7%), and mean postoperative FTA was greater in the computer-assisted group that in the conventional HTO group (valgus 9.0° vs. valgus 7.6°, p<0.001). The five- and 10-year survival rates were 97.1% and 89.6%, respectively. No difference was detected in nine-year survival rates (p=0.369) between the two groups, although the clinical and radiographic results were better in the computer-assisted group that those in the conventional HTO group. ConclusionsMid-term survival rates did not differ between computer-assisted and conventional HTOs. A comparative analysis of longer-term survival rate is required to demonstrate the long-term benefit of computer-assisted HTO. Level of evidenceIII

Minimum 5-year Follow-up Results of Minimally Invasive Total Knee Arthroplasty Using Mini-Keel Modular Tibial Implant.

PurposeTo evaluate the minimum 5-year mid-term clinical and radiological results of minimally invasive surgery total knee arthroplasty (MIS-TKA) using a mini-keel modular tibia component.Materials and MethodsWe retrospectively evaluated 254 patients (361 cases) who underwent MIS-TKA between 2005 and 2006. The latest clinical and radiological assessments were done in 168 cases that had been followed on an outpatient basis for more than 5 postoperative years. Clinical results were assessed using the Hospital for Special Surgery (HSS) score and Knee Society score. Radiological evaluation included measurements of knee alignment.ResultsThe average postoperative knee range of motion and HSS score were 134.3°±12.4° and 92.7°±7.0°, respectively. The average postoperative femorotibial angle and tibial component alignment angle were 5.2°±1.7° valgus and 90.2°±1.6°, respectively. The average tibial component posterior inclination was 4.8°±2.1°. The percentage of cases with tibial component alignment angle of 90°±3° was 96.1%, and that with the femorotibial angle of 6°±3° valgus was 94.0%. Radiolucent lines were observed in 20 cases (12.0%): around the femur, tibia, and patella in 14 cases, 10 cases, and 1 case, respectively. However, they were less than 2 mm and non-progressive in all cases. The survival rate was 99.4% and there was no implant-related revision.ConclusionsMIS-TKA using a mini-keel modular tibial plate showed satisfactory results, a high survival rate, and excellent clinical and radiological results in the mid-term follow-up.

Comparative Outcomes of Open-Wedge High Tibial Osteotomy With Platelet-Rich Plasma Alone or in Combination With Mesenchymal Stem Cell Treatment: A Prospective Study

This study compared the clinical results and second-look arthroscopic findings of patients undergoing open-wedge high tibial osteotomy (HTO) for varus deformity, with or without mesenchymal stem cell (MSC) therapy. This prospective, comparative observational study was designed to evaluate the effectiveness of MSC therapy. The patients were divided into 2 groups: HTO with platelet-rich plasma (PRP) injection only (n = 23) or HTO in conjunction with MSC therapy and PRP injection (n = 21). Prospective evaluations of both groups were performed using the Lysholm score, Knee Injury and Osteoarthritis Outcome Score (KOOS), and a visual analog scale (VAS) score for pain. Second-look arthroscopy was carried out in all patients at the time of metal removal. The patients in the MSC-PRP group showed significantly greater improvements in the KOOS subscales for pain (PRP only, 74.0 ± 5.7; MSC-PRP, 81.2 ± 6.9; P < .001) and symptoms (PRP only, 75.4 ± 8.5; MSC-PRP, 82.8 ± 7.2; P = .006) relative to the PRP-only group. Although the mean Lysholm score was similarly improved in both groups (PRP only, 80.6 ± 13.5; MSC-PRP, 84.7 ± 16.2; P = .357), the MSC-PRP group showed a significantly greater improvement in the VAS pain score (PRP only, 16.2 ± 4.6; MSC-PRP, 10.2 ± 5.7; P < .001). There were no differences in the preoperative (PRP only, varus 2.8° ± 1.7°; MSC-PRP, varus 3.4° ± 3.0°; P = .719) and postoperative (PRP only, valgus 9.8° ± 2.4°; MSC-PRP, valgus 8.7° ± 2.3°; P = .678) femorotibial angles or weight-bearing lines between the groups. Arthroscopic evaluation, at plate removal, showed that partial or even fibrocartilage coverage was achieved in 50% of the MSC-PRP group patients but in only 10% of the patients in the PRP-only group (P < .001). MSC therapy, in conjunction with HTO, mildly improved cartilage healing and showed good clinical results in some KOOS subscores and the VAS pain score compared with PRP only. Level II, prospective comparative study.

Minimally invasive unicompartmental knee arthroplasty for spontaneous osteonecrosis of the knee joint

Objective To explore the outcome and surgical technique of minimally invasive unicompartmental knee arthroplasty (UKA) for spontaneous osteonecrosis of the knee joint.Methods From January 2009 to June 2013,twenty-seven cases with medial compartmental spontaneous osteonecrosis treated by minimally invasive Oxford phase 3 UKA were reviewed retrospectively.Twelve knees were male and 15 were female,with an average age of 64.6±8.6 years (52-82 years).At the time of diagnosis,11 patients presented with grade Ⅲ necrosis,and 16 grade Ⅳ,following Mont's classification.The pain,range of motion (ROM) and HSS score of the knees were evaluated before and after UKA.Pre-and post-operative alignment of the low limbs were measured and compared respectively.According to the guidelines proposed by the Oxford group,postoperative radiographic assessments were made at the final follow-up.Results All of the patients were followed up for a mean time of 27.8± 15.9 months (6-59months).There were no serious adverse events such as infection,bearing dislocation,aseptic loosening,pulmonary embolism,deep venous thrombosis,cardio-cerebral vascular incident or psychogenia.There was 1 revision from unrelated causes (fracture of tibia plateau) at 3 years after arthroplasty.One femoral component was tilted with postoperative radiographic angle ＞ 10°.One radiolucent line was observed in the SONK series.There were no clinical symptoms of the two implant failures at the last follow up.VAS score was reduced from 6.9±0.9 to 2.0±1.1 (t=19.27,P=0.00).96.3％ (26/27) of pain was relieved.The mean post-operative ROM and femorotibial angle were 125.7°±9.6°,177.7°±3.1°,respectively.HSS score was increased from 61.3±9.7 to 93.0±4.8 (t=14.46,P=0.00).Of the patients,96.3％ (26/27) were satisfied with the outcome of this surgical procedure.Conclusion Minimally invasive UKA is an effective method for spontaneous osteonecrosis of the knee with fewer traumas and fast recovery.The early term outcome of UKA is encouraging. Key words: Arthroplasty, replacement, knee; Knee joint; Osteonecrosis

Do we need to do overcorrection in Blount’s disease?

In order to prevent recurrent deformity, overcorrection in Blount's disease has been a common practice by most paediatric orthopaedic surgeons. However, some patients have persistent valgus alignment resulting in awkward deformity. The femoro-tibial angle (FTA) was measured in this series of cases to determine the necessity of such practice. During 1998-2010, patients with Blount's disease stage 2 by Langenskiold, aged from 30 to 40 months who had failed from bracing and underwent valgus osteotomy were included. Seventeen legs had postoperative FTA 7-13° (group 1) and 48 legs had postoperative FTA more than 13° (group 2). ROC curve was used to determine the appropriate FTA that was suitable to prevent recurrence. Four legs had recurrence (28.6%) in group 1 and six legs (12.5%) had recurrence in group 2. Chi-square test between two groups were not statistically significant in recurrence (p = 0.434). Age and BMI were not statistically significant between recurrent and non-recurrent groups. The ROC curve shows that overcorrection more than 15° did not show benefit to prevent the recurrence in Blount's stage 2. Our study showed that the overcorrection group had non-statistically significant recurrence compared to the non-overcorrection group, and overcorrection more than valgus 15° has no benefit to prevent recurrence.