O-Sung Lee

Postoperative Imaging of Bioabsorbable Anchors in Rotator Cuff Repair

Background: Bioabsorbable anchors may lead to osteolysis and cyst formation. However, the prevalence of these outcomes is not known for rotator cuff repairs. Purpose: To evaluate cyst formation after placement of bioabsorbable anchors for rotator cuff repairs and to verify whether bioabsorbable anchors degraded as intended and preserved bone stock for possible revision compared with metal anchors. The null hypothesis was that the rate and severity of cyst formation around the anchor are negligible. Study Design: Case series; Level of evidence, 4. Methods: Between April 2008 and November 2011, a total of 209 patients (85 men, 124 women) underwent rotator cuff repair with bioabsorbable suture anchors (113 with polylactic acid enantiomers [PLLA] and 96 with poly-D,L-lactide from L-lactide and D-lactide [PLDLA]); the patients underwent magnetic resonance imaging (MRI) evaluation more than 10 months after surgery. The fluid signal around the anchor on T2-weighted MRI scans was graded as follows: grade 0, no fluid around anchor; grade 1, minimal fluid around anchor; grade 2, local fluid around anchor; grade 3, fluid collection around entire length of anchor with cyst diameter less than twice the anchor diameter; and grade 4, cyst diameter larger than grade 3. The integrity of repairs was also evaluated. Results: Cysts were observed in 97 instances (46.4%). There were 41 grade 1 cases (19.6%), 16 grade 2 (7.7%), 22 grade 3 (10.5%), and 18 grade 4 (8.6%). Healing of repaired tendon was observed in 131 patients (62.7%). There was no statistical difference in healing rate between patients with and without cyst formation (66.1% vs 58.8%; P = .276). Altered anchor shape and absorption were not observed in most of the patients. However, in 12 patients (6 with PLLA and 6 with PLDLA anchors), T2-weighted scans showed that the signal intensity of anchors had changed since surgery, which could indicate that absorption had taken place; nonetheless, even in these 12 patients, anchors were clearly visible on T1-weighted scans. Conclusion: Osteolysis and cyst formation are common complications following the use of bioabsorbable anchors in rotator cuff repairs. Considering that adequate absorption of anchors and preservation of bone stock are the reasons for using bioabsorbable anchors, use of these anchors should be reconsidered because of possible interference with revision surgery.

Kinematic alignment is a possible alternative to mechanical alignment in total knee arthroplasty

PurposeA systematic review was conducted to answer the following questions: (1) Does kinematically aligned (KA) total knee arthroplasty (TKA) achieve clinical outcomes comparable to those of mechanically aligned (MA) TKA? (2) How do the limb, knee, and component alignments differ between KA and MA TKA? (3) How is joint line orientation angle (JLOA) changed from the native knee in KA TKA compared to that in MA TKA?MethodsNine full-text articles in English that reported the clinical and radiological outcomes of KA TKA were included. Five studies had a control group of patients who underwent MA TKA. Data on patient demographics, clinical scores, and radiological results were extracted. There were two level I, one level II, three level III, and three level IV studies. Six of the nine studies used patient-specific instrumentation, one study used computer navigation, and two studies used manual instrumentation.ResultsThe clinical outcomes of KA TKA were comparable or superior to those of MA TKA with a minimum 2-year follow-up. Limb and knee alignment in KA TKA was similar to those in MA TKA, and component alignment showed slightly more varus in the tibial component and slightly more valgus in the femoral component. The JLOA in KA TKA was relatively parallel to the floor compared to that in the native knee and not oblique (medial side up and lateral side down) compared to that in MA TKA. The implant survivorship and complication rate of the KA TKA were similar to those of the MA TKA.ConclusionSimilar or better clinical outcomes were produced by using a KA TKA at early-term follow-up and the component alignment differed from that of MA TKA. KA TKA seemed to restore function without catastrophic failure regardless of the alignment category up to midterm follow-up. The JLOA in KA TKA was relatively parallel to the floor similar to the native knee compared to that in MA TKA. The present review of nine published studies suggests that relatively new kinematic alignment is an acceptable and alternative alignment to mechanical alignment, which is better understood. Further validation of these findings requires more randomized clinical trials with longer follow-up.Level of evidenceLevel II.

Efficacy of a Topical Gelatin-Thrombin Matrix Sealant in Reducing Postoperative Drainage Following Anterior Cervical Discectomy and Fusion

Study Design Retrospective fusion level(s)-, age-, and gender-matched analysis. Purpose To determine whether the application of a topical gelatin-thrombin matrix sealant (Floseal) at the end of anterior cervical discectomy and fusion (ACDF) can reduce the amount of postoperative hemorrhage. Overview of Literature The effect of the matrix sealant in decreasing postoperative hemorrhage following ACDF has not been reported. Methods Matrix sealant was (n=116, study group) or was not applied (n=58, control group) at the end of ACDF. Patients were selected by 1:2 matching criteria of fusion level(s), age, and gender. Seven parameters described below were compared between the two groups. Results The total drain amount for the first 24 hours (8±9 versus 27±22 mL), total drain amount until the 8-hour drainage decreased to ≤10 mL (8±10 versus 33±26 mL), and the total drain amount until 6 AM on the first postoperative day (7±8 versus 24±20 mL) were significantly lower in the study group than the control group (all p<0.001). The time for the 8-hour drainage to decrease to ≤10 mL was significantly lower in the study group (10±5 versus 26±14 hours, p<0.001). The 8-hour drainage decreased to ≤10 mL on the operation day in most patients (88%) in the study group versus mostly on the first (48%) or second (33%) postoperative day in the control group (p<0.001). The total drain amount until 6 AM on the first postoperative day was 0 mL in 43% of patients in the study group and in 7% in the control group (p<0.001). No patient in either group required hematoma evacuation. Conclusions Application of the topical matrix sealant at the end of ACDF can significantly reduce the amount of postoperative hemorrhage.

Retro-tubercular gap widening can be caused by inappropriate anterior osteotomy and large opening gap in the medial biplanar open-wedge HTO

PurposeThe purpose of this study was to investigate the causes of retro-tubercular gap widening and to confirm whether this widened gap causes instability of the osteotomy configuration during open-wedge high tibial osteotomy (OWHTO).MethodsOperative records and radiologic findings of patients who underwent biplanar medial OWHTO between 2014 and 2016 were retrospectively evaluated. To identify the osteotomy configuration including lateral hinge fracture, postoperative simple radiographs and CT images were analyzed. Postoperative CT scan was used to evaluate the widening of the retro-tubercular gap, thickness, and axial angle of retro-tubercular osteotomy, as well as the ratios of anterior and posterior osteotomy, and hinge length. The correlation of each factor was evaluated and analyzed in accordance with the lateral hinge fracture (LHF).ResultsWidening of the retro-tubercular gap showed a significant correlation with the axial angle of retro-tubercular osteotomy, anterior osteotomy ratio, and opening gap distance, but not with the thickness of retro-tubercular osteotomy, posterior osteotomy ratio, and hinge length ratio. The LHF group showed significantly larger value than the non-LHF group with respect to the thickness of retro-tubercular osteotomy (P = 0.003), axial angle of retro-tubercular osteotomy (P = 0.033), retro-planar gap distance (P = 0.001), anterior osteotomy ratio (P = 0.000), and opening gap distance (P = 0.003). The hinge length ratio was smaller in the LHF group than in the non-LHF group (P = 0.001). However, the posterior osteotomy ratio was not different between the two groups (n.s.).ConclusionRetro-tubercular gap widening can be caused by inappropriate anterior osteotomy and large opening gap distance, which can be related to LHF. Therefore, anterior cortical osteotomy may also be an important factor for preventing instability of the proximal fragment in biplanar OWHTO.Level of EvidenceCase–control study, Level III.

Comparison of the Leg-Length Change between Opening- and Closing-Wedge High Tibial Osteotomy: A Systematic Review and Meta-Analysis

&NA; The aim of this meta‐analysis was to compare the effects of closing‐wedge (CW) and opening‐wedge (OW) high tibial osteotomies (HTOs) on the change in leg length. Our hypotheses were that leg length will increase after OW HTO and decrease after CW HTO, and the magnitude of the change in leg length would be negligible in both techniques. Multiple databases including MEDLINE, Embase, and Cochrane were searched for studies comparing the change in leg length after HTO with that before HTO. After testing for publication bias and heterogeneity, we aggregated variables by using the random‐effects model. The weighted mean differences of leg length were estimated before and after OW and CW HTOs with 95% confidence intervals (CIs). Four studies that analyzed 127 OW HTOs and 175 CW HTOs were included in this meta‐analysis. Leg length increased by 6.96 mm after OW HTO (95% CI: ‐3.43 to 17.36) and decreased by 1.95 mm after CW HTO (95% CI: ‐10.89 to 7). Additionally, the change in leg length after OW HTO had a positive correlation with the degree of correction. The leg length increased after OW HTO, and the increase was sufficiently large to cause clinical concerns. The change in leg length after CW HTO was negligible despite the decrease in length. Therefore, CW HTO seems to be a better treatment option than OW HTO if a large correction is required.

Effect of the Referencing System on the Posterior Condylar Offset and Anterior Flange-Bone Contact in Posterior Cruciate-Substituting Total Knee Arthroplasty

BACKGROUND The effect of referencing system on posterior condylar offset (PCO) after total knee arthroplasty (TKA) is still controversial. Moreover, there is a lack of concern about the anterior flange-bone contact according to the referencing system. METHODS One hundred four TKAs using the anterior referencing (AR) system and 107 TKAs using the posterior referencing (PR) system were analyzed with 2-year follow-up. The PCO, PCO ratio (PCOR), and contact at the anterior flange-bone interface were compared between the 2 groups. The flexion and extension gaps and the degree of medial release were measured, and clinical outcomes were evaluated. Finally, the correlation between changes in PCO and knee flexion angle was analyzed. RESULTS The mean postoperative PCO and PCOR were significantly larger in the PR group than in the AR group. Incomplete contact between the anterior flange and anterior femur occurred more frequently in the AR group than in the PR group (48.1% vs 13.1%, P < .001). The medial and lateral flexion gaps were significantly larger in the AR group than in the PR group. The groups showed no differences in soft tissue release, degree of flexion, and clinical scores. In both groups, there was no correlation between postoperative change of PCO and improvement in flexion. CONCLUSION The PR system produced larger PCO and PCOR, and smaller flexion gap compared to the AR system. Additionally, the PR group showed more favorable contact between the anterior flange and anterior femur. However, these differences were not related to the degree of soft tissue release and clinical outcomes.

Change in gait after high tibial osteotomy: A systematic review and meta-analysis

We conducted a meta-analysis to analyze how high tibial osteotomy (HTO) changes gait and focused on the following questions: (1) How does HTO change basic gait variables? (2) How does HTO change the gait variables in the knee joint? Twelve articles were included in the final analysis. A total of 383 knees was evaluated. There were 237 open wedge (OW) and 143 closed wedge (CW) HTOs. There were 4 level II studies and 8 level III studies. All studies included gait analysis and compared pre- and postoperative values. One study compared CWHTO and unicompartmental knee arthroplasty (UKA), and another study compared CWHTO and OWHTO. Five studies compared gait variables with those of healthy controls. One study compared operated limb gait variables with those in the non-operated limb. Gait speed, stride length, knee adduction moment, and lateral thrust were major variables assessed in 2 or more studies. Walking speed increased and stride length was increased or similar after HTO compared to the preoperative value in basic gait variables. Knee adduction moment and lateral thrust were decreased after HTO compared to the preoperative knee joint gait variables. Change in co-contraction of the medial side muscle after surgery differed depending on the degree of frontal plane alignment. The relationship between change in knee adduction moment and change in mechanical axis angle was controversial. Based on our systematic review and meta-analysis, walking speed and stride length increased after HTO. Knee adduction moment and lateral thrust decreased after HTO compared to the preoperative values of gait variables in the knee joint.