Medially and distally inserted tuberosity screw fixation of the osteotomized tubercle is safe and effective in retro-tubercular bi-planar opening-wedge high tibial osteotomy.

PURPOSE: The purpose of this study was to develop a safe and effective method of inserting one tuberosity screw and to determine whether retro-tubercular (RT)-Open-wedge high tibial osteotomy (OWHTO) with tuberosity screw fixation can be conducted to overcome the problem of osteotomized tubercle and produce favorable outcomes compared to RT-OWHTO without tuberosity screw fixation. METHODS: From 2018 to 2020, patients who underwent bi-planar RT-OWHTO were allocated as two groups (RT-OWHTO without tuberosity screw fixation as group I and with screw fixation as group II). Computed tomography (CT) was used to analyze osteotomy configurations such as RT gap and tip distance, and union of the main and second plane osteotomy sites. The RT gap distance was measured as the length of the osteotomy gap. The RT tip distance was measured as the length of the gap at the tip of the tibial tubercle. Post-operative complications were analyzed also. To evaluate the neurovascular (NV) approximity of screw fixation group, the pre-operative magnetic resonance imaging (MRI) images were referenced on the post-operative CT for the assessment of the safe zone. RESULTS: In total, 44 knees in group I and 46 knees in group II were enrolled. The RT gap distance (2.58 ± 0.69 mm vs. 0.57 ± 0.57 mm; p < .001) and RT tip distance (4.31 ± 1.60 mm vs. 1.48 ± 1.42 mm; p < .001) were significantly larger in group I than in group II. The sum of union grade in the second plane osteotomy site (17.93 ± 2.18 points vs. 22.24 ± 2.57 points; p < .001) was statistically different between two groups at three months post operatively. Post-operative tuberosity prominence occurred in five knees only in group I (p = 0.025), although tibial tuberosity fracture developed in seven cases in group II compared with two cases in group I with no statistical significance. NV was safe when the screw was inserted medially. CONCLUSION: RT-OWTHO with one-screw fixation for the tuberosity was effective in terms of tuberosity prominence and the union of the second plane osteotomy site. However, it also produced another problem, such as tuberosity fracture. In addition, a tuberosity screw was safe when it was inserted in the medial-distal direction. LEVEL OF EVIDENCE: Cohort study; level III.

Analysis of the determinant factor of the medial joint space width after medial opening wedge high tibial osteotomy.

INTRODUCTION: The decrease in the medial joint space width (MJSW) in patients with osteoarthritis (OA) is proportional to the degree of arthritis. The purpose of this study was to evaluate the affecting factors of the MJSW by serial radiologic assessment after medial open wedge high tibial osteotomy (MOW-HTO). MATERIALS AND METHODS: Between March 2014 and March 2019, 162 MOW-HTO knees that underwent serial radiologic assessment and follow-up MRI were enrolled. Changes in the MJSW were analyzed by dividing into three groups: group I, low quartile (< 25%); II, middle quartile (25-75%); and III, high quartile (> 75%), according to the magnitude of the MJSW. The correlation between the MJSW and weight-bearing line ratio (WBLR), hip knee ankle angle (HKA), joint line convergence angle (JLCA), medial proximal tibial angle (MPTA), mechanical lateral distal femoral angle (m-LDFA), joint line orientation angle (JLOA), and MRI cartilage status was analyzed. Multiple linear regression analysis was used to analyze factors affecting the amount of change in the MJSW. The clinical outcome was also correlated with the MJSW. RESULTS: The amount of change in the JLCA, which has the largest beta value (weight-bearing standing anteroposterior (AP) view and 45° flexion posteroanterior view (Rosenberg view) ß = - 0.699 and ß = -5.221, both p < 0.001, respectively), had the greatest contribution to the change in the MJSW. The WBLR was also related (standing AP and Rosenberg ß = 0.177 and ß = 0.264, p = 0.015 and p = 0.004, respectively). There was no statistical difference between the amount of change in the MJSW and the change in cartilage. The clinical outcomes did not differ between the groups. CONCLUSION: The JLCA was the most important contributing factor for the MJSW, followed by WBLR. This contribution was more pronounced in Rosenberg view than standing AP view. Changes in cartilage status were not related to the MJSW and JLCA. The clinical outcome was not related to the MJSW, either. Level of evidence Cohort study; level III.

Is there any benefit in the combined ligament reconstruction with osteotomy compared to ligament reconstruction or osteotomy alone?: Comparative outcome analysis according to the degree of medial compartment osteoarthritis with anterior or posterior cruciate ligament insufficiency.

INTRODUCTION: The purpose of this study was to compare the outcomes of middle-aged patients with anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) insufficiency by assessing different groups: high tibial osteotomy (HTO), HTO with combined ligament reconstruction, and isolated ligament reconstruction according to the alignment change and medial compartment osteoarthritis (OA). MATERIALS AND METHODS: From 2014 to 2019, middle-aged (40-65 years) patients with knee instability were enrolled in this retrospective study. They were categorized into three groups: group I, HTO; group II, HTO with combined ACL or PCL reconstruction; and group III, isolated ligament reconstruction. Radiological outcomes, including Kellgren-Lawrence grade, mechanical femorotibial angle (mFTA), weight-bearing line (WBL) ratio, and posterior tibial slope were compared. Knee stability and clinical outcomes were also compared. RESULTS: Seventy-nine patients completed the final assessment. Group I was older than other two groups (p = 0.006). Groups I and II had a higher body mass index (p = 0.043) and more preoperative varus alignment than group III (p < 0.001). OA severity was ranked in the order of group I, II, and III (p < 0.001). Group I showed more valgus alignment than group II after HTO (p = 0.024 for mFTA and 0.044 for WBL ratio, respectively). Compared to their preoperative status, all three groups showed significant improvement in knee stability (p < 0.001); however, group I showed inferior knee stability regardless of ACL or PCL reconstruction (p < 0.001 and 0.043, respectively). All clinical scores significantly improved in the three groups (p < 0.001), and they showed comparable clinical outcomes in the final assessment. CONCLUSIONS: Our strategy in managing middle-aged patients with knee instability according to the varus alignment and medial degeneration showed favorable stability and clinical outcomes. Middle-aged patients with knee instability should be managed with different strategies depending on their status. LEVEL OF EVIDENCE: Case-control study; Level-III.

Excessively Increased Joint-Line Obliquity After Medial Opening-Wedge High Tibial Osteotomy Is Associated With Inferior Radiologic and Clinical Outcomes: What Is Permissible Joint-Line Obliquity.

PURPOSE: This study aimed to evaluate the permissible joint-line obliquity (JLO) based on radiologic and clinical outcomes with midterm follow-up after medial open-wedge high tibial osteotomy (MOWHTO). METHODS: Patients who had undergone MOWHTO from March 2014 to May 2016 were retrospectively evaluated. They were divided into 4 groups based on JLO as represented by postoperative medial proximal tibial angle (MPTA). Radiologic parameters including MPTA, joint-line orientation angle (JLOA), joint-line convergence angle (JLCA), posterior tibial slope, weightbearing line ratio (WBLR), and coronal translation were analyzed. Clinical outcomes were evaluated with American Knee Society Score (AKSS), Western Ontario and McMaster University Index, and short-form 36 health survey (SF-36). The changes between preoperation and final follow-up in JLOA and MPTA were defined as ΔJLOA and ΔMPTA. RESULTS: A total of 135 knees were finally included (MPTA ≤90.32° as group I; 90.33° to 92.62° as group II; 92.74° to 95.22° as group III; and ≥95.23° as group IV). The last follow-up MPTA, JLOA, and JLCA values were different between the groups (P < .001, P < .001, and P = .015, respectively). WBLR and JLOA positively correlated with MPTA; however, WBLR showed an abrupt increase at MPTA >96.5°, and the JLOA distribution tended to be greater than the regression line at MPTA >96°. Moreover, ΔJLOA was not as large as ΔMPTA. The percentage of patients attaining a minimal clinically important difference was significantly lower in the AKSS-functional score and SF-36 physical component summary in group IV (P = .008 and 0.021, respectively). CONCLUSION: The JLOA did not change as much as the MPTA, but an MPTA >95.2° abruptly increased the JLOA and valgus overcorrection after MOWHTO. Poor clinical outcomes were more evident in excessive MPTA (>95.2°) than in mildly undercorrected or properly corrected MPTA (<95.2°). LEVEL OF EVIDENCE: III, retrospective cohort study.

Additional tying on the adjustable-loop device improves the outcomes of anterior cruciate ligament reconstruction using hamstring autograft.

PURPOSE: The purpose of this study was to verify the efficacy of a novel technique for additional tying on the adjustable-loop device to prevent stress concentration on the graft loop end and gradual loop lengthening. METHODS: A total of 124 patients who underwent anterior cruciate ligament reconstruction using hamstring autografts from 2014 to 2017 were included in this retrospective study. After 1:1 propensity score matching, two groups were formed (group I: 50 patients without tying vs. group II: 50 patients with tying). Anterior laxity was evaluated using side-to-side differences. Tunnel length, loop length, and graft-tunnel gap were measured using follow-up magnetic resonance imaging. The signal-to-noise ratio was calculated at the loop end, loop inner side, tunnel entrance, and graft mid-substance. The clinical outcomes were assessed using the International Knee Documentation Committee score, Lysholm score, pivot shift test, and Lachman test. RESULTS: The average follow-up period was 63.2 ± 4.8 and 53.8 ± 11.9 months in groups I and II, respectively. Anterior laxity showed that side-to-side differences improved significantly 6 months postoperatively in both the groups. Although the anterior laxity improved in group II (2.9 ± 1.0 to 1.6 ± 0.8, p < 0.001), it deteriorated in group I (2.5 ± 1.5 to 3.3 ± 1.3 mm, p < 0.001) at the final follow-up. The graft-tunnel gap was significantly larger in group I (p < 0.001). The signal-to-noise ratios of the loop end and loop inner side were significantly higher in group I (p < 0.001 and p = 0.020, respectively). The clinical outcomes at the final follow-up were not significantly different between the groups. CONCLUSION: The additional tying on the adjustable-loop device was not superior to the control group in clinical stability examination or outcome. However, it was effective in anterior laxity measured by stress radiographs, preventing stress on the adjustable-loop device, and gradual graft loop lengthening. LEVEL OF EVIDENCE: Level III.

Comparison of the effect of total knee arthroplasty and high tibial osteotomy on coronal pelvic and ankle-hindfoot alignment.

BACKGROUND: Total knee arthroplasty (TKA) and high tibial osteotomy (HTO) are different procedures on the continuous spectrum of osteoarthritic knee treatments. TKA aims for neutral alignment and HTO aims for slight valgus. METHODS: 2:2:2:1 propensity score matching yielded 100, 100, 100, and 50 patients with unilateral TKA, bilateral TKA, unilateral HTO, and bilateral HTO, respectively. Radiological evaluations of pelvis, knee, ankle, and hindfoot were performed. The important factors affecting the alignment change of the adjacent joints were identified, and subgroup analyses were performed using the identified parameters. The clinical outcomes were also compared. RESULTS: The coronal alignments of the adjacent joints were corrected to the neutral position after TKA and HTO. The tibiotalar tilt angle (TTTA) was a common factor that affected changes in the ankle and hindfoot alignment. Patients with larger preoperative TTTA showed larger changes in TTTA in both TKA and HTO groups (P < 0.001). Patients with larger preoperative hindfoot alignment angle (HAA) showed larger changes in tibial plafond inclination, talar inclination, and HAA in both TKA and HTO groups (P < 0.001). TKA groups showed negative pelvic tilt values in the horizontal plane, and HTO groups showed a larger weight-bearing line ratio. CONCLUSION: Even more severe deformities including adjacent joints were observed in TKA patients, both TKA and HTO patients showed improved alignment of the adjacent joints. However, HTO patients showed closer normal alignment than patients who underwent TKA. The preoperative TTTA and HAA were important factors for restoration of ankle and hindfoot alignment after knee surgery.

Outcomes of Distal Medial Collateral Ligament Release During Opening-Wedge High Tibial Osteotomy.

Background: During opening-wedge, high-tibial osteotomy (OWHTO), various methods of managing the superficial medial collateral ligament (sMCL) can be performed to obtain a sufficient medial side opening. Purpose/Hypothesis: The purpose of this study was to evaluate the outcomes of distal sMCL release during OWHTO. It was hypothesized that distal sMCL release would not cause valgus instability. Study Design: Case series; Level of evidence, 4. Methods: This retrospective study included 77 patients who underwent OWHTO between January 1, 2018, and October 31, 2019, and completed serial radiological assessments including weightbearing line ratio (WBLR), medial proximal tibial angle (MPTA), coronal translation, total tibial plateau inclination (TTPI), valgus medial joint-space width (valgus-MJSW), valgus joint-line convergence angle (valgus-JLCA), varus lateral joint-space width (varus-LJSW), and varus joint-line convergence angle (varus-JLCA) on standing whole-leg and varus-valgus stress radiographs. Subgroup analysis of pre- to postoperative changes in radiologic parameters was performed according to TTPI (group 1: <25th percentile, group 2: 25th-75th percentile, group 3: >75th percentile) and Ahlbäck osteoarthritis classification (group 1: Ahlbäck grade 1, group 2: Ahlbäck grades 2 and 3). Results: The mean time to final follow-up was 34.6 ± 6.4 months. The WBLR and coronal translation did not change significantly over the follow-up period. The valgus-MJSW at 6 months postoperatively was significantly wider than that preoperatively and at 1 year postoperatively (P < .001). The varus-LJSW at 6 months postoperatively was significantly wider compared with preoperatively and 1 year postoperatively (P < .001), and the varus-LJSW at 1 year postoperatively was wider than that found preoperatively. Coronal translation was significantly more reduced for patients in TTPI group 1 versus group 3 (P = .019). There was no significant differences according to the Ahlbäck groups. All clinical outcomes improved at final follow-up compared with preoperative values (P ≤ .002). Conclusion: The study findings indicated that sMCL release did not cause valgus instability or valgus overcorrection at 1 year postoperatively, and improved clinical outcomes were seen at the final follow-up compared with preoperative status after OWHTO with sMCL release.

Do Individualized Patient-Specific Situations Predict the Progression Rate and Fate of Knee Osteoarthritis? Prediction of Knee Osteoarthritis.

Factors affecting the progression rate and fate of osteoarthritis need to be analyzed when considering patient-specific situation. This study aimed to identify the rate of remarkable progression and fate of primary knee osteoarthritis based on patient-specific situations. Between May 2003 and May 2019, 83,280 patients with knee pain were recruited for this study from the clinical data warehouse. Finally, 2492 knees with pain that were followed up for more than one year were analyzed. For analyzing affecting factors, patient-specific information was categorized and classified as demographic, radiologic, social, comorbidity disorders, and surgical intervention data. The degree of contribution of factors to the progression rate and the fate of osteoarthritis was analyzed. Bone mineral density (BMD), Kellgren-Lawrence (K-L) grade, and physical occupational demands were major contributors to the progression rate of osteoarthritis. Hypertension, initial K-L grade, and physical occupational demands were major contributors to the outcome of osteoarthritis. The progression rate and fate of osteoarthritis were mostly affected by the initial K-L grade and physical occupational demands. Patients who underwent surgical intervention for less than five years had the highest proportion of initial K-L grade 2 (49.0%) and occupations with high physical demand (41.3%). In identifying several contributing factors, the initial K-L grade and physical occupational demands were the most important factors. BMD and hypertension were also major contributors to the progression and fate of osteoarthritis, and the degree of contribution was lower compared to the two major factors.

Reducing the Risk of Neurovascular Injury With Posteromedial Plating and Laterally Directed Screw Insertion During Opening-Wedge High Tibial Osteotomy.

Background: Neurovascular injury is a serious complication after opening-wedge high tibial osteotomy (OWHTO). Purpose: To evaluate (1) how neurovascular injuries during fixation can be prevented and (2) whether a lateral hinge-directed posteromedial fixation system provides comparable neurovascular safety during OWHTO to conventional and custom-made locking plate systems. Study Design: Cohort study; Level of evidence, 3. Methods: Included were 275 knees that underwent OWHTO from March 2014 to May 2018. The knees were divided into 4 groups based on the type of fixation system used: (1) lateral hinge-directed system (LCfit HTO; LCfit group), (2) TDM decisive wedge locking plate (TDM group), (3) OhtoFix anatomic locking metal block plate (OhtoFix group), and (4) TomoFix titanium locking plate (TomoFix group). Using postoperative computed tomography, the following variables among the groups were compared: screw insertion angle relative to the tibia posterior cortex in the axial plane, length, proximity to neurovascular structures, and safety angle of screw fixation (angle between the most proximal posterior screw insertion line and a line tangent to the popliteal artery from the screw hole). Radiological and clinical outcomes were also compared between groups. Results: The screw angle was significantly smaller and the distance from neurovascular structures to the screw extension line was significantly farther in the LCfit group compared with the other 3 groups (P < .001 for both). The safety angle was also wider in the LCfit group than in the other groups (P < .001). There were no significant differences in radiologic or clinical outcomes between the groups during follow-up. Conclusion: The distance from the neurovascular structures to the screw extension line was significantly farther, and the safety angle was also significantly wider with the laterally directed posteromedial plate system compared with the other systems. There were no neurovascular injuries in any group or significant differences in clinical outcomes or radiological parameters between the LCfit and the other locking plate systems.

Factors Associated With Unfavorable Radiological Outcomes After Opening-Wedge High Tibial Osteotomy for Varus Knees.

Background: Corrective osteotomy around the knee is based on deformity profiles of the femoral and tibial sides. Opening-wedge high tibial osteotomy (OWHTO) can be favored if the outcomes are not different, even if there is a certain degree of abnormal parameters after correction. Purpose/Hypothesis: The purpose of this study was to identify the factors associated with unfavorable radiological outcomes after OWHTO for varus knees. Our hypothesis was that there would be an optimal situation in which double-level osteotomy (DLO) has advantages over isolated OWHTO and an optimal cutoff value of structural parameters for which DLO should be considered in patients with severe varus knees. Study Design: Case-control study; Level of evidence, 3. Methods: The radiological and clinical outcomes of 337 patients who underwent OWHTO were retrospectively evaluated. A subgroup analysis was performed according to the weightbearing line ratio (WBLR) (group 1: <25th percentile; group 2: 25th-75th percentile; and group 3: >75th percentile) and factors associated with unfavorable radiological outcomes. For the assessment of cutoff values of the parameters favoring DLO, unfavorable radiological outcomes were categorized as follows: (1) medial proximal tibial angle (MPTA) >95°, (2) joint-line convergence angle (JLCA) >4° (insufficient medial release), (3) JLCA <0° (medial instability), (4) recurrence of a varus deformity, and (5) lateral hinge fracture. Results: The mean follow-up period was 66.2 ± 19.1 months. A low preoperative WBLR was related to a larger preoperative to postoperative change (Δ) in the WBLR, a larger reduction in coronal translation, a larger ΔMPTA, a wide preoperative lateral joint space, and a narrow preoperative medial joint space (P < .001, P < .001, P < .001, P = .016, and P = .003, respectively). However, only an MPTA >95° was significantly related to a low WBLR in the subgroup analysis according to unfavorable radiological outcomes (P = .038). The cutoff value of ΔWBLR causing an MPTA >95° was 46.5%, which showed a good area under the curve of 0.800, with a sensitivity of 74.4% and a specificity of 82.7%. The clinical outcomes significantly improved at the final follow-up compared with those preoperatively, with no significant differences between the WBLR groups. Conclusion: A ΔWBLR ≥46.5% led to an MPTA >95°. However, clinical outcomes were not affected. DLO should be considered if the surgeon desires a postoperative MPTA ≤95°.