Surgical Technique and Preliminary Outcomes of Double-Level Osteotomy for Valgus Deformity.

Background: Data are limited regarding the surgical technique or outcomes of double-level osteotomy (DLO) combining medial closing-wedge distal femoral osteotomy and medial closing-wedge high tibial osteotomy in patients with moderate-to-severe valgus deformity. Purpose/Hypothesis: To describe the surgical technique and assess the short-term outcomes and surgical accuracy of DLO in patients with a moderate or severe valgus deformity. It was hypothesized that this technique would result in good clinical outcomes with precise deformity correction. Study Design: Case series; Level of evidence, 4. Methods: Eight patients (mean age, 44.2 ± 10.9 years) with a moderate or severe valgus knee treated with DLO (9 knees; mechanical tibiofemoral angle [mTFA], 10.3°± 3.5°) were included. The mean follow-up was 25.1 ± 11.1 months. Preoperative to postoperative changes in radiographic parameters (mTFA, mechanical lateral distal femoral angle, mechanical medial proximal tibial angle, joint line convergence angle) and clinical scores (Hospital for Special Surgery score, Oxford Knee Score, Lysholm score) were assessed. Surgical accuracy was calculated by subtracting the achieved postoperative correction from the preoperatively planned targeted correction. Results: The mTFA changed significantly from 10.3°± 3.5° preoperatively to -1.8°± 3.4° postoperatively (P < .001); the mechanical lateral distal femoral angle and mechanical medial proximal tibial angle changed significantly by 5.1°± 2.7° and 5.9°± 2.2°, respectively (P < .001 for both); and the posterior distal femoral angle decreased significantly from 85.9°± 3.1° to 84.2°± 2.4° (P < .01). There was no significant difference between pre- and postoperative joint line convergence angles (3.3°± 2.3° to 2.6°± 2.1°). The accuracy of the correction was high: the mTFA achieved postoperatively differed from the mTFA planned preoperatively by a mean of 2.7°± 1.9° (range, 0.6°-6.6°). Significant pre- to postoperative improvement was seen for all outcome scores (Hospital for Special Surgery, from 67 ± 11 to 93 ± 4; Oxford Knee Score, from 29 ± 7 to 43 ± 3; Lysholm, from 41 ± 24 to 89 ± 8; P < .001 for all). Conclusion: High surgical accuracy was achieved, and patients who underwent varus DLO for valgus knees showed improved knee function at short-term follow-up. Varus DLO can be a surgical option to restore the optimal alignment and joint line obliquity in patients with moderate or severe valgus malalignment.

Radiologic simulation of leg length change after double level osteotomy in preoperative surgical planning.

BACKGROUND: To evaluate the expected postoperative total leg length change using preoperative radiographs during surgical planning of four different methods of double level osteotomy (DLO). METHODS: This study included 34 patients (44 knees) who underwent DLO for varus knee osteoarthritis. Surgical planning was performed so that the postoperative weight bearing line ratio was 62.5%. In DLO, lateral closed or medial open wedge distal femoral osteotomy (LCWDFO, MOWDFO) was performed so that the postoperative mechanical lateral distal femoral angle was 85°, and residual deformity was corrected with medial open or lateral closed wedge high tibial osteotomy (MOWHTO, LCWHTO). Pre- and surgical planning X-rays in the one-leg standing position were compared to assess the change in leg length, and the factors affecting it, in the various surgical groups. The proportion of cases in which Δ total leg length was greater than 6 mm (symptomatic change) was investigated. RESULTS: The mean postoperative total leg length increased significantly with LCWDFO + MOWHTO, MOWDFO + MOWHTO, and MOWDFO + LCWHTO, while it decreased with LCWDFO + LCWHTO. The proportion of cases with a postoperative total leg length change > 6 mm was 72.7%, 2.3%, 100%, and 6.8% in LCWDFO + MOWHTO, LCWDFO + LCWHTO, MOWDFO + MOWHTO, and MOWDFO + LCWHTO, respectively. In addition, the preoperative hip-knee-ankle angle correlated negatively with the postoperative total leg length change in LCWDFO + MOWHTO, MOWDFO + MOWHTO, and MOWDFO + LCWHTO, but not in LCWDFO + LCWHTO. CONCLUSIONS: MOWDFO + MOWHTO had the largest postoperative leg length change and MOWDFO + LCWHTO had the smallest. Symptomatic leg length change (> 6 mm) should be considered in MOWDFO + MOWHTO and LCWDFO + MOWHTO.

Cartilage Degeneration of the Lateral Compartment of the Knee at Second-Look Arthroscopy Is Associated With Deterioration of 10-Year Clinical Outcomes After Opening-Wedge High Tibial Osteotomy.

PURPOSE: To identify the arthroscopic findings associated with deterioration of 10-year clinical outcomes after opening-wedge high tibial osteotomy (OWHTO) in patients with knee osteoarthritis. METHODS: A total of 114 consecutive knees of 91 patients with knee osteoarthritis who underwent OWHTO between 2007 and 2011 were retrospectively reviewed. Of these patients, those who underwent second-look arthroscopy and were followed up for a minimum of 10 years were enrolled. The Knee Society Score (KSS) and hip-knee-ankle angle were assessed. Cartilage status was graded at the time of osteotomy (first look) and plate removal (second look) according to the International Cartilage Repair Society (ICRS) grading system. The KSS knee subscale score and function subscale score were assessed separately, and on the basis of the changes in each of these scores from 1 to 10 years postoperatively and the minimal clinically important difference (MCID), the patients were divided into 2 groups: deteriorated (deterioration of score ≥ MCID) and non-deteriorated (deterioration of score < MCID). RESULTS: Sixty-nine knees were included in this study. The mean knee score improved continuously from 48.7 ± 11.3 preoperatively to 86.8 ± 10.3 at 1 year (P < .001), 87.5 ± 9.9 at 5 years (P < .001), and 86.5 ± 10.5 at 10 years (P < .001) postoperatively. The mean function score also improved continuously from 62.5 ± 12.1 preoperatively to 90.7 ± 12.9 at 1 year (P < .001), 91.6 ± 12.1 at 5 years (P < .001), and 88.5 ± 13.1 at 10 years (P < .001) postoperatively. Three knees underwent conversion to total knee arthroplasty within 10 years postoperatively. The deteriorated KSS group showed significantly progressed ICRS grades in the lateral compartment compared with the non-deteriorated KSS group. The ICRS grade in the lateral compartment at second-look arthroscopy was identified as the only significant factor associated with both knee score deterioration (odds ratio, 4.89; P = .03) and function score deterioration (odds ratio, 3.91; P = .03) on multivariable logistic regression analysis. CONCLUSIONS: The presence of cartilage degeneration of the lateral compartment of the knee at second-look arthroscopy is associated with deterioration of long-term clinical outcomes after OWHTO. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Can double-level osteotomy prevent patellofemoral osteoarthritis progression compared with open wedge high tibial osteotomy?

PURPOSE: To compare radiographic, clinical, and arthroscopic findings in patellofemoral (PF) osteoarthritis (OA) between open wedge high tibial osteotomy (OWHTO) and double-level osteotomy (DLO) with the same operative indication. METHODS: After adjustment for patient age, and coronal alignment, 36 knees with OWHTO alone and 36 knees with DLO were compared. Radiographic, clinical, and arthroscopic findings were documented before osteotomy. Arthroscopic findings were observed 1 year after osteotomy, and clinical and radiographic findings were observed 2 years after osteotomy. Patellar height was evaluated using the Insall-Salvati (IS) ratio, Carton-Deschamps (CD) index, and Blackburne-Peel (BP) index. Lateral patellar tilt and patellar shift were measured. A power analysis was performed. RESULTS: The postoperative CD and BP indices in the OWHTO group were lower than those in the DLO group (p < 0.001 and p = 0.001, respectively). The CD and BP indices in both groups significantly decreased postoperatively (all p < 0.001). Tilting angles in the OWHTO and DLO groups significantly decreased postoperatively (p < 0.001 and p = 0.002, respectively). There were no significant differences in American Knee Society scores, Kujala score, and the Knee Injury and Osteoarthritis Outcome Scores between both groups. The PF OA progression of the trochlear in the OWHTO group was higher than that in the DLO group (p = 0.002), and the PF OA progression of the patellar facet in the DLO group and anterior femoral condyle in both groups on the lateral side were higher than those on the medial side (p = 0.006, 0.032, and 0.041, respectively). CONCLUSIONS: DLO decreased the rate of low patellar height compared with OWHTO. DLO decreased the rate of PF OA progression in the trochlea compared with OWHTO. There were no significant differences in clinical outcomes in both groups. LEVEL OF EVIDENCE: Level III, case-control study.

Patient-specific instrumentation for total knee arthroplasty improves reproducibility in the planned rotational positioning of the tibial component.

BACKGROUND: The purpose of this study was to evaluate the reproducibility of planned component positioning including tibial rotational alignment in patient-specific instrumentation (PSI) for total knee arthroplasty (TKA). METHODS: A total of 100 knees of 100 patients underwent TKA using PSI (n = 50) or the conventional method (n = 50). Full-length anteroposterior radiographs of the lower limb were taken in the standing position, and the coronal alignments of the femoral and tibial components were measured. Computed tomography (CT) images of the lower limb were obtained preoperatively and postoperatively, and the rotational alignments of the femoral and tibial components were measured. The difference from the preoperative planning in tibial rotational alignment was measured using three-dimensionally merged pre- and postoperative images. The mean values and rates of outliers in each measurement were compared between the PSI group and the conventional group. RESULTS: There were no significant differences in coronal alignment of the femoral and tibial components and rotational alignment of the femoral component between the two groups. With respect to rotational alignment of the tibial component from the preoperatively planned reference axis, the PSI group showed a lower rate of outliers (internal rotation > 10°) than the conventional group (p < 0.05). CONCLUSIONS: This study demonstrated that the difference from the preoperative planning in tibial rotational positioning was accurately evaluated using novel three-dimensional measurement method, and PSI could reduce outliers in rotational alignment of the tibial component (internal rotation > 10°). PSI is a useful technique for improving the reproducibility of the planned tibial rotational positioning in TKA.

Minimum 5-Year Outcomes of Osteochondral Autograft Transplantation with a Concomitant High Tibial Osteotomy for Spontaneous Osteonecrosis of the Knee with a Large Lesion.

OBJECTIVE: The purpose of this study was to evaluate the mid-term clinical outcomes of osteochondral autograft transplantation (OAT) with concomitant high tibial osteotomy (HTO) in spontaneous osteonecrosis of the knee (SONK) with a large lesion. DESIGN: A total of 48 knees of 48 consecutive patients with SONK (lesion size ≥4 cm2, no age criteria) who underwent opening wedge HTO and concomitant OAT were retrospectively investigated, and those who were followed up postoperatively for at least 5 years were included in this case series study. Clinical outcomes were evaluated using knee and function scores of Knee Society Score, radiographic outcomes were evaluated using the anatomical femorotibial angle (FTA), and these outcomes were compared between patients aged ≥70 years and <70 years. RESULTS: Of the 48 cases, a total of 43 cases were available for review at a minimum of 5 years, and 5 cases were excluded from the analysis. Overall, the mean knee score improved from preoperative 48.8 ± 13.3 to postoperative 87.9 ± 8.6 at 1 year (P < 0.05) and 85.0 ± 10.4 at final follow-up (P < 0.05 vs. preop., N.S. vs. 1 year). The mean function score also improved from preoperative 60.1 ± 10.9 to postoperative 87.3 ± 12.2 at 1 year (P < 0.05) and 84.2 ± 12.4 at final follow-up (P < 0.05 vs. preop., N.S. vs. 1 year). The mean standing FTA was corrected significantly from 181.1° ± 2.7° preoperatively to 169.7° ± 2.4° at 1 year (P < 0.05) and 169.4° ± 3.1° at final follow-up (P < 0.05 vs. preop., N.S. vs. 1 year). There were no significant differences in clinical and radiographic outcomes between patients aged ≥70 years and <70 years. There were 4 cases of lateral hinge fracture around the osteotomy site and 1 case of delayed union. None of the patients underwent revision surgery during the follow-up period (survival rate of 100%). CONCLUSIONS: Mid-term clinical outcomes of patients with SONK who underwent HTO and OAT with a relatively large lesion were good.

Biological Effects of High Tibial Osteotomy on Spontaneous Osteonecrosis of the Knee.

OBJECTIVE: The purpose of this study was to evaluate the postoperative status of spontaneous osteonecrosis of the knee (SONK) after high tibial osteotomy (HTO) with concomitant bone marrow stimulation (BMS) using synovial fluid (SF) biomarkers. DESIGN: Twenty patients with SONK who underwent opening wedge HTO were enrolled. Paired SF samples from the affected knee were collected at the time of HTO surgery and at the time of plate removal. SF concentrations of interleukin (IL)-6, IL-8, and matrix metalloproteinase (MMP)-13 were measured by enzyme-linked immunosorbent assays. The Knee Society Score (KSS) and hip-knee-ankle (HKA) angle were assessed before and 2 years after HTO. RESULTS: The KSS knee and function scores were significantly improved after HTO (mean changes of 33.8 and 29.4, respectively). The mean HKA angle was changed from mechanical varus (-8.6°) to valgus (5.2°). Concentrations of IL-6, IL-8, and MMP-13 were significantly decreased after HTO (mean changes of -73.7%, -32.4%, and -47.9% from preoperative baseline, respectively). Significant correlations were found between lesion size and concentrations of biomarkers, except for preoperative MMP-13. CONCLUSIONS: SF levels of biomarkers of inflammation and cartilage degradation were reduced after HTO with a concomitant BMS procedure, suggesting a biological improvement in SONK.

Joint line obliquity was maintained after double-level osteotomy, but was increased after open-wedge high tibial osteotomy.

PURPOSE: To compare the radiographic, clinical, and arthroscopic outcomes of varus osteoarthritic knees treated with an open-wedge high tibial osteotomy (OWHTO) alone or with a double-level osteotomy (DLO). It was hypothesized that treatment with DLO would maintain the joint line obliquity (JLO) and acquire better arthroscopic and clinical outcomes after surgery than OWHTO alone. METHODS: Knees with predicted medial proximal tibial angle (MPTA) > 95° were treated with OWHTO alone or with DLO. Preoperatively, age, body mass index, and hip-knee-ankle angle (HKA) differed between the two groups. Therefore, after adjustment for those factors, 34 knees with OWHTO alone and 34 knees with DLO were compared. On whole-leg radiographs for a single leg, HKA, weightbearing line (WBL) ratio, lateral distal femoral angle (LDFA), MPTA, and JLO were measured before and 2 years after surgery. Clinical outcomes were evaluated by the Knee Society Score (KSS) knee, KSS function, Lysholm, and Knee injury and Osteoarthritis Outcome Score (KOOS) scores before and 2 years after surgery. Arthroscopic findings were obtained before and 1 year after surgery. Various factors were compared between the two groups. RESULTS: JLO increased significantly from 1.4° to 6.3° in the OWHTO group (p < 0.001) and changed from 1.0° to 1.3° in the DLO group (n.s.). Postoperative MPTA and JLO in the OWHTO group were significantly higher than those in the DLO group (both p < 0.001). There were no significant differences in the KSS knee, KSS function, and KOOS scores between the two groups. Postoperative Lysholm score in the DLO group was higher than that in the OWHTO group (p < 0.025). Femoral and tibial cartilage regeneration in the medial condyles and deterioration in the lateral condyles did not differ between the two groups on second-look arthroscopy. CONCLUSIONS: JLO was not significantly changed after surgery in the DLO group. DLO enabled the acquisition of physiological JLO compared with OWHTO alone. LEVEL OF EVIDENCE: Retrospective comparative study, Level III.

Return to sports activity after opening wedge high tibial osteotomy in patients aged 70 years and older.

BACKGROUND: The purpose of this study was to evaluate return to sports (RTS) after opening wedge high tibial osteotomy (OWHTO) in elderly patients and associated factors affecting RTS. METHODS: Seventy-four patients (mean age 68 years) who underwent OWHTO were enrolled. Clinical outcomes were evaluated using the Knee Society Score (KSS). Patients were asked regarding types of sports activities and their levels of participation within preoperative 1 year and postoperative 1 year. Levels of participation in sports and recreational activities were examined using the Tegner activity scale. The outcomes were compared between two age groups (≥ 70 years vs. < 70 years). RESULTS: Of the 74 patients overall, 59 participated in at least one sport preoperatively, and 55 returned to sports postoperatively (RTS 93%). The KSS knee score and function score were significantly improved after surgery in both age groups (P < 0.05), but no significant differences were found between the age groups. The Tegner activity scales for ≥ 70 years and < 70 years were 2.9 ± 1.1 and 4.0 ± 1.9 preoperatively (P < 0.01) and 2.7 ± 1.2 and 3.3 ± 1.4 postoperatively (P = 0.16), respectively. RTS was reported by 24 of 25 (96.0%) in the age < 70 years group and 31 of 34 (91.2%) in the age ≥ 70 years group. Majority of age ≥ 70 years participated in low-impact sports preoperatively and returned to the same impact level postoperatively. CONCLUSIONS: The rate of RTS after OWHTO was high in patients aged 70 years and older with low-impact level. OWHTO is a preferred surgical option for elderly patients who desire RTS.

No differences in clinical outcomes and cartilage repair between opening wedge and closed wedge high tibial osteotomies at short-term follow-up: A retrospective case series analysis.

PURPOSE: The aim of this study was to assess differences in clinical outcomes and postoperative cartilage repair between opening wedge high tibial osteotomy (OWHTO) and closed wedge HTO (CWHTO) for medial osteoarthritis (OA) of the knee. METHODS: A total of 90 knees of 76 patients who underwent OWHTO (45 knees of 40 patients) and CWHTO (45 knees of 36 patients) was followed-up for 2 years. Cartilage repair at the medial compartment was arthroscopically classified into the following stages: Stage 1 (no reparative change); Stage 2 (partial coverage with white cartilaginous tissue); and Stage 3 (full coverage with white cartilaginous tissue). Clinical outcomes were assessed using Knee Society scores, and radiographic assessment was carried out by anatomical femorotibial angle (aFTA). RESULTS: Regarding preoperative OA grade, varus alignment, and function score, CWHTO patients showed more advanced OA status than OWHTO patients. Knee scores and function scores were significantly improved after surgery with both HTO procedures (P < 0.05), with no significant difference between the two procedures. Cartilage repair of stage 2 or 3 was found in more than 80% of the subjects in the medial femoral condyle and more than 60% in the medial tibial condyle. However, there were no significant differences between the two HTO procedures. Multivariate logistic regression analysis showed that preoperative International Cartilage Repair Society (ICRS) grade was the only factor affecting cartilage repair. CONCLUSIONS: CWHTO improved clinical outcomes and cartilage status as much as OWHTO. Although the effects of cartilage repair on clinical outcomes are unknown, HTO is an effective treatment option even for severe medial OA of the knee.

Open-wedge high tibial osteotomy using intraoperative control of joint line convergence angle with reference to preoperative supine radiograph.

INTRODUCTION: Preoperative supine joint line convergence angle (JLCA) correlates with postoperative standing JLCA. Here, we compared the radiographic and clinical outcomes of knees with preoperative JLCAs of ≥ 4° and < 4° in open-wedge high tibial osteotomy (OWHTO). We hypothesized that the postoperative coronal alignment in both groups would not be affected by a change in JLCA if this change could predict before surgery. MATERIALS AND METHODS: Eighty-four patients with medial knee osteoarthritis who underwent OWHTO were enrolled retrospectively. A weight-bearing line (WBL) ratio of 62% and a JCLA equivalent to the preoperative supine JLCA were anticipated in preoperative planning. These were intraoperatively set using an alignment rod and a radiolucent protractor under fluoroscopy. Soft tissue correction was defined as correction angle minus bone correction. The participants with preoperative JLCAs of < 4° (low-JLCA group) and ≥ 4° (high-JLCA group) were compared. RESULTS: No significant difference in the coronal alignment was found between the groups after OWHTO. No significant differences in correction angle or bone correction were found between the groups, but the soft tissue correction in the high-JLCA group was higher than that in the low-JLCA group after OWHTO (p = 0.013). CONCLUSIONS: When we controlled intraoperative JLCA, the postoperative coronal alignment was not affected by the change in JLCA and the differences in soft tissue correction between the low-JLCA and high-JLCA groups. However, overcorrection compared with the target coronal alignment remained in both groups. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

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

BACKGROUND: The 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). METHODS: A 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. RESULTS: The 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). CONCLUSIONS: A 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.

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

PURPOSE: The purpose of this study was to evaluate the area of the osteotomy surface, including the flange and wedge volume, in open wedge high tibial osteotomy (OWHTO), distal tibial tuberosity osteotomy (DTO), and distal tibial tuberosity arc osteotomy (DTAO) using tibial sawbones. It was hypothesized that the area of the osteotomy surface, including the flange, in DTAO was larger than that in OWHTO and DTO and that the wedge volume in DTAO was smaller than that in OWHTO and DTO. METHODS: Fifteen tibial sawbones were divided equally into three groups: OWHTO, DTO, and DTAO. The total area of the osteotomy surface in OWHTO, DTO, and DTAO was compared using image analysis software. The contact area of the flange and the wedge volume at wedge heights of 5, 10, and 15 mm were compared among osteotomy types. One-way repeated-measures analysis of variance was used to compare the total area of the osteotomy surface, the contact area of the flange, and the wedge volume at 5, 10, and 15 mm in OWHTO, DTO, and DTAO. RESULTS: The total area of the osteotomy surface in DTO and DTAO was significantly larger than that in OWHTO (P < 0.05). The contact area of the flange in DTAO was significantly larger than that in OWHTO at each wedge height (P < 0.05). In addition, the contact area of the flange in DTAO was significantly larger than that in DTO at wedge heights of 5 and 15 mm (P < 0.05). The wedge volume in DTAO was significantly smaller than that in DTO at each wedge height (P < 0.05). CONCLUSIONS: This study demonstrated that an increase in the flange contact area and a decrease in the wedge volume in the opening gap were found in DTAO compared to DTO. This would be an advantage for anteroposterior screw insertion from the flange to the distal tibial fragment and bone union at the osteotomy site.

Varus inclination of the tibia is related to patellofemoral osteoarthritis in Japanese female patients with moderate knee osteoarthritis.

PURPOSE: The aim of this study was to investigate whether the tibial tuberosity-trochlear groove (TT-TG) distance and lateral patellar tilt, which induce patellofemoral osteoarthritis (OA), are related to the coronal deformity of the lower limb in varus knee OA. It was hypothesized that varus inclination of the tibia was negatively correlated with the TT-TG distance and lateral patellar tilt in Japanese female patients with moderate knee OA. METHODS: A total of 104 female patients (139 knees) scheduled to undergo knee osteotomy for varus knee OA were enrolled. The coronal lower limb alignment was measured on anteroposterior whole-leg radiographs. The TT-TG distance, patellar tilt angle, and the patellofemoral joint space were measured both medially and laterally on computed tomography images. The correlations between coronal lower limb alignment and the TT-TG distance or patellar tilt angle, and the correlations between the TT-TG distance or patellar tilt angle and patellofemoral joint space were evaluated. RESULTS: The medial proximal tibial angle was negatively correlated with the TT-TG distance (r = - 0.383, P < 0.01) and patellar tilt angle (r = - 0.34, P < 0.01). Lateral patellofemoral joint space was negatively correlated with the TT-TG distance (r = - 0.256, P = 0.002) and patellar tilt angle (r = - 0.205, P = 0.016). CONCLUSIONS: Varus inclination of the proximal tibia may induce lateralization of the tibial tuberosity and lateral patellar tilt. The tibial tuberosity lateralization and lateral patellar tilt may induce lateral patellofemoral OA in patients with varus knee OA. LEVEL OF EVIDENCE: III.

Coronal shaft bowing of the femur affects varus inclination of the surgical transepicondylar axis in varus knee osteoarthritis.

PURPOSE: This study investigated the relationship between femoral shaft bowing and the orientation of the surgical transepicondylar axis (TEA) in the coronal plane in varus knee osteoarthritis (OA). METHODS: A total of 82 knees scheduled to undergo total knee arthroplasty (TKA) for the treatment of varus knee OA were enrolled. The hip-knee-ankle angle (HKA) was measured preoperatively on anteroposterior whole-leg standing radiographs. The lateral angle between the TEA and the mechanical axis of the femur (MA-TEA) was measured in the coronal plane from preoperative computed tomography (CT) images. Femoral shaft bowing was measured on CT images. Pearson's correlation coefficient was used to examine the correlation of the MA-TEA with the HKA and femoral shaft bowing. RESULTS: The MA-TEA correlated negatively with the HKA (r = - 0.321, P < 0.01) and positively with femoral shaft bowing (r = 0.415, P < 0.01). CONCLUSIONS: The TEA changed to varus as femoral shaft bowing increased in patients with varus knee OA. This suggests that the TEA is not always the centre of the rotational axis of the femur after TKA. In addition, the TEA may not be useful as a consistent parameter in the coronal plane in patients with increasing femoral shaft bowing. LEVEL OF EVIDENCE: III.

Intraoperatively accurate limb alignment after opening wedge high tibial osteotomy can be lost by large knee joint line convergence angle during surgery.

INTRODUCTION: The purpose of this study was to assess early postoperative loss of achieved correction and associated factors after opening wedge high tibial osteotomy (OWHTO). MATERIALS AND METHODS: OWHTO was performed in 121 patients with osteoarthritis of the knee (mean age 66 years, 154 knees). Anteroposterior radiographs of the knee and full-length leg, and varus and valgus stress radiographs of the knee were taken, and the femorotibial angle (FTA), joint line convergence angle (JLCA), and medial proximal tibial angle (MPTA) were measured. The changes in the FTA, JLCA, and MPTA were defined as ΔFTA, ΔJLCA, and ΔMPTA. RESULTS: The ΔFTA and ΔJLCA at postoperative 0-2 days were - 1.8 ± 1.2° and - 1.9 ± 1.4°, respectively. The ΔFTA, ΔJLCA and ΔMPTA at postoperative 1-12 months were 0.9 ± 1.3°, 0.2 ± 1.2° and - 0.8 ± 0.8°, respectively. A positive correlation was found between ΔFTA and ΔJLCA at postoperative 0-2 days (ρ = 0.642, P < 0.001) and at postoperative 1-12 months (ρ = 0.402, P < 0.001). A negative correlation was found between ΔFTA and ΔMPTA at postoperative 1-12 months (ρ = - 0.534, P < 0.001). A discrepancy in alignment represented by the FTA occurred in the supine radiographs between the day of surgery and postoperative 2 days. Multiple regression analysis suggested that postoperative JLCA on the day of surgery was the factor related to early postoperative change of the FTA. CONCLUSIONS: This study demonstrated the early loss of achieved correction after OWHTO due to change of the JLCA, even if the accurate alignment is obtained intraoperatively.