Arthroscopic cystectomy for Baker's cysts with and without one-way valve lesions: incidence of one-way valve lesion, associated pathologies, and clinical outcomes.

INTRODUCTION: A one-way valve lesion plays an important role in the formation of Baker's cysts and serves as an important landmark for accessing these cysts during arthroscopic surgery. This study aimed to investigate the incidence of one-way valve lesions and their effect on clinical outcomes in patients who underwent arthroscopic cystectomy for Baker's cysts. MATERIALS AND METHODS: Patients who underwent arthroscopic cystectomy for Baker's cysts between June 2005 and November 2017 were retrospectively reviewed. Patient demographic characteristics, radiologic/arthroscopic findings (presence of one-way valve lesions, concurrent chondral and meniscal lesions, and cyst wall thickness), and clinical outcomes (clinical recurrence rate, Lysholm score, and complications) at the 2-year follow-up were evaluated. Subgroup analysis was performed to compare clinical outcomes between patients with and without one-way valve lesions. RESULTS: Thirty patients (mean age, 57.4 ± 9.4 years) were included in this study. One-way valve lesions were surgically documented in 11 patients (36.7%). Ten patients (33.3%) had chondral lesions with an International Cartilage Repair Society grade ≥ 3, and 23 patients (76.7%) had concurrent chondral and meniscal lesions. At the 2-year follow-up, none of the patients had experienced clinical recurrence; the mean Lysholm score was 76.3 ± 17.5 (48-100). Three patients reported persistent pain, while two reported numbness or paresthesia. Subgroup analysis showed no significant differences in clinical recurrence rates, Lysholm scores, and complication rates between the groups. CONCLUSIONS: The incidence of one-way valve lesions during arthroscopic cystectomy for Baker's cysts was lower than that previously reported. Arthroscopic cystectomy showed good clinical results in patients with and without these lesions.

Mesenchymal Stem Cells for Enhanced Healing of the Medial Collateral Ligament of the Knee Joint.

Background and Objectives: The medial collateral ligament (MCL) is one of the major supporting ligaments of the knee joint, and MCL injuries are common where excessive valgus loading is applied to the knee joint. Although most MCL injuries can be treated conservatively, healing of the MCL can take several weeks to months. Furthermore, once injured, the biomechanical properties of the healed MCL differ from those of the native MCL, resulting in an increased risk of re-injury and chronic remnant symptoms. Mesenchymal stem cells (MSCs), owing to their therapeutic potential, have been investigated in various musculoskeletal injuries, and some preclinical studies regarding MSC-based approaches in MCL injuries have shown promising results. Despite satisfactory results in preclinical studies, there is still a lack of clinical studies in the orthopedic literature. This article describes the basic knowledge of the MCL, standard treatments for MCL injuries, and recent studies regarding the application of MSCs for enhanced healing of the MCL. MSC-based approaches are expected to be a potential therapeutic option for enhanced healing of the MCL in the future.

Effect of Adding Kinesio Taping to Exercise Therapy in the Treatment of Patellofemoral Pain Syndrome.

Background and objectives: Patellar taping has been widely used for the primary or adjunctive treatment of patellofemoral pain syndrome (PFPS); however, there are limited data in terms of functional outcomes. This study aimed to investigate whether there is any beneficial effect of adding Kinesio Taping® (KT) to exercise therapy in the treatment of PFPS. Materials and Methods: Twenty patients (27.5 ± 5.4 years) with PFPS who applied KT and 19 patients (27.3 ± 7.4 years) who did not were included in this study. Quadriceps muscle strength and acceleration time (AT) were assessed using an isokinetic device. Patient-reported outcomes were evaluated using the Kujala anterior knee pain scale (AKPS). Both groups underwent one-month exercise therapy. Results: There was no significant difference in quadriceps strength, AT, and AKPS at baseline and at 1 month between the taping and non-taping groups (p > 0.05). However, for quadriceps muscle strength, the effect of time*group interaction was statistically significant (F(1.37) = 4.543, p < 0.05, partial eta squared 0.109), showing that improvement in the quadriceps strength was higher in the non-taping group than that in the taping group. Conclusions: Adding KT to exercise therapy did not elicit extra benefits in quadriceps muscle strength and AT, and AKPS among PFPS with abnormal patellar tracking at one month.

Anatomical and Biomechanical Characteristics of the Anterolateral Ligament: A Descriptive Korean Cadaveric Study Using a Triaxial Accelerometer.

Background and Objectives: The anterolateral ligament (ALL) could be the potential anatomical structure responsible for rotational instability after anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to investigate the anatomical and biomechanical characteristics of the ALL in Korean cadaveric knee joints. Materials and Methods: Twenty fresh-frozen cadaveric knees were dissected and tested. Femoral and tibial footprints of the ALL were recorded. Pivot shift and Lachman tests were measured with KiRA. Results: The prevalence of ALL was 100%. The average distance of the tibial footprint to the tip of the fibular head was 19.85 ± 3.41 mm; from the tibial footprint to Gerdy's tubercle (GT) was 18.3 ± 4.19 mm; from the femoral footprint to the lateral femoral epicondyle was 10.25 ± 2.97 mm. ALL's footprint distance was the longest at 30° of flexion (47.83 ± 8.05 mm, p < 0.01) in a knee with intact ALL-ACL and neutral rotation. During internal rotation, the footprint distance was the longest at 30° of flexion (50.05 ± 8.88 mm, p < 0.01). Internal rotation produced a significant increase at all three angles after ACL-ALL were transected (p = 0.022), where the footprint distance was the longest at 30° of flexion (52.05 ± 7.60 mm). No significant difference was observed in KiRA measurements between intact ALL-ACL and ALL-transected knees for pivot shift and Lachman tests. However, ACL-ALL-transected knees showed significant differences compared to the intact ALL-ACL and ALL-transected knees (p < 0.01). Conclusions: The ALL was identified as a distinct ligament structure with a 100% prevalence in this cadaveric study. The ALL plays a protective role in internal rotational stability. An isolated ALL transection did not significantly affect the ALL footprint distances or functional stability tests. Therefore, the ALL is thought to act as a secondary supportive stabilizer for rotational stability of the knee joint in conjunction with the ACL.

Component gap measurement reflects the planned gap balance during total knee arthroplasty more accurately and reliably than bone surface gap measurement.

PURPOSE: This study aimed to compare the reliability of two gap assessment methods (component and bone surface gap measurement vs. planned gap balance) and identify the contributors to component gaps other than planned gaps. METHODS: The prospectively collected data for 122 consecutive primary total knee arthroplasties (TKAs; 114 patients). After femoral planning for gap balancing, the medial and lateral planned gaps were calculated (planned gap). The established medial extension and flexion gaps (MEG and MFG, respectively) and lateral extension and flexion gaps (LEG and LFG, respectively) were measured with and without the TKA components (bone surface and component gaps) at 0° and 90° flexion. The intraclass and Pearson correlation coefficients for each gap measurement method were assessed using planned gap values, and multiple linear regression analyses were performed to identify the contributors to component gaps. RESULTS: Compared with the bone surface gap measurement, the component gap measurement showed higher reliability and stronger correlation with the planned gap balance for each gap. The changes in the medial posterior femoral offset contributed to the MEG and LEG, whereas those in the joint line height contributed to the LEG. The changes in the hip-knee-ankle angle and lateral posterior femoral offset contributed to the LFG. CONCLUSION: Component gap measurements of the established gap more accurately and reliably reflect the planned gap balance than do bone surface gap measurements. The established gaps are affected by several factors other than femoral planning.

Residual varus alignment can reduce joint awareness, restore joint parallelism, and preserve the soft tissue envelope during total knee arthroplasty for varus osteoarthritis.

PURPOSE: The objectives were to compare the coronal joint configuration of the knee joints, coronal gap imbalances requiring substantial medial release, and patient-reported outcomes, including the forgotten joint score, between knees in which residual varus alignment was intentionally allowed according to an individualised lower limb analysis and those with mechanical alignment in total knee arthroplasty for varus osteoarthritis. METHODS: Consecutive primary navigated total knee arthroplasty procedures for varus osteoarthritis were retrospectively reviewed. The study cohort was stratified based on whether residual varus alignment was intentionally allowed. Propensity-score matching was performed based on the baseline characteristics, including demographic characteristics, preoperative radiological measurements, and the Western Ontario and McMaster University Osteoarthritis Index (mechanical alignment group vs residual varus group). The patient-reported outcomes and coronal joint line orientation of the knee (relative to the ground) and ankle were evaluated. Coronal gap differences and coronal gap imbalances were analysed using intraoperative gap measurements. RESULTS: Relative to the ground and ankle, the postoperative knee joint line orientation slanted down laterally in the mechanical alignment group (- 3.05˚ ± 1.62, relative to the ground; - 2.65˚ ± 1.56, relative to the ankle joint), but was parallel in the residual varus group (- 0.75˚ ± 1.59, relative to the ground; - 0.95˚ ± 1.71, relative to the ankle joint). Coronal gap differences at extension and the proportion of coronal gap imbalances requiring substantial medial release were 1.27 ± 1.53 and 6% in the residual varus group and 2.32 ± 1.24 and 15% in the mechanical alignment group. Postoperatively, the residual varus group showed higher Western Ontario and McMaster University Osteoarthritis Index scores and total forgotten joint scores than the mechanical alignment group (6.97 ± 4.75 vs. 10.31 ± 5.74 and 56.42 ± 12.85 vs. 45.69 ± 14.49, respectively). CONCLUSION: Intentionally allowed residual varus alignment with individualised analysis of lower limb alignment restored the parallel joint line of the knees, preserved the soft tissue envelope, and reduced joint awareness after total knee arthroplasty for varus osteoarthritis. LEVEL OF EVIDENCE: Therapeutic, Level III retrospective case-control study.

Combined Anterior Cruciate Ligament and Anterolateral Ligament Reconstruction Using a Single Achilles Tendon Allograft: A Technical Note.

Clinical outcomes after anterior cruciate ligament reconstruction (ACLR) have improved remarkably. However, residual rotational instability of the knee joint remains a major concern. The anterolateral ligament (ALL) has recently gained interest as a secondary stabilizer of knee joint rotatory instability, and this has led to the attempt of ALL reconstruction (ALLR) in combination with ACLR to restore rotational stability in patients with anterior cruciate ligament (ACL) injury. Although several techniques for ALLR have recently been introduced, the ideal graft type and surgical technique for combined ACLR and ALLR are yet to be established. This technical note therefore aimed at introducing a novel surgical procedure involving the use of a single Achilles tendon allograft as a relatively simple and minimally invasive procedure for combined ALL and ACL reconstruction.

Acute Obturator Externus Injury in Professional Soccer Players: A Case Series.

When patients present with hip or groin pain, proximal quadriceps or adductor injuries are often initially suspected. In this case report, however, we present three cases of professional soccer players who were found to have obturator externus injury. A 30-year-old player and a 24-year-old player complained of pain in the left side after long distance shooting during an in-season training session and a match, respectively. Another 24-year-old player complained of pain in the right side after long distance passing during a preseason training session. On physical examination, active hip external rotation and passive hip internal rotation and extension elicited pain in all three players. All three players underwent magnetic resonance imaging (MRI) which found obturator externus grade II injuries for two players and grade I injury for one player. Rehabilitation protocols included relative rest, cryotherapy, and electrotherapy over a period of one week. All patients were able to return to play after 10 days. Correct identification of obturator externus injury afforded our players a favorable prognosis and a relatively quick return-to-sport compared with quadricep or adductor injury.

Anatomy, Biomechanics, and Reconstruction of the Anterolateral Ligament of the Knee Joint.

Despite remarkable advances in the clinical outcomes after anterior cruciate ligament reconstructions (ACLRs), residual rotational instability of the knee joint remains a major concern. Since the anterolateral ligament (ALL) on the knee joint has been "rediscovered", the role of anterolateral structures, including ALL and deep iliotibial band, as secondary stabilizers of anterolateral rotatory instability has gained interest. This interest has led to the resurgence of anterolateral procedures combined with ACLRs to restore rotational stability in patients with anterior cruciate ligament (ACL) deficiencies. However, the difference in concepts between anterolateral ligament reconstructions (ALLRs) as anatomical reconstruction and lateral extra-articular tenodesis (LETs) as non-anatomical reinforcement has been conflicting in present literature. This study aimed to review the anatomy and biomechanics of anterolateral structures, surgical techniques, and the clinical outcomes of anterolateral procedures, including LET and ALLR, in patients with ACL deficiencies.

Adjustable-Loop Cortical Suspensory Fixation Results in Greater Tibial Tunnel Widening Compared to Interference Screw Fixation in Primary Anterior Cruciate Ligament Reconstruction.

Background: Although the use of adjustable-loop suspensory fixation has increased in recent years, the influence of the shortcomings of suspensory fixation, such as the bungee-cord or windshield-wiper effects, on tunnel widening remains to be clarified. Hypothesis/Purpose: The purpose of this study was to compare adjustable-loop femoral cortical suspensory fixation and interference screw fixation in terms of tunnel widening and clinical outcomes after anterior cruciate ligament reconstruction (ACLR). We hypothesized that tunnel widening in the adjustable-loop femoral cortical suspensory fixation (AL) group would be comparable to that in the interference screw fixation (IF) group. Methods: This study evaluated patients who underwent primary ACLR at our institution between March 2015 and June 2019. The femoral and tibial tunnel diameters were measured using plain radiographs in the immediate postoperative period and 2 years after ACLR. Tunnel widening and clinical outcomes (Lysholm score, 2000 International Knee Documentation Committee subjective score, and Tegner activity level) were compared between the two groups. Results: There were 48 patients (mean age, 29.8 ± 12.0 years) in the AL group and 44 patients (mean age, 26.0 ± 9.5 years) in the IF group. Tunnel widening was significantly greater in the AL group than that in the IF group at the tibia anteroposterior (AP) middle (2.03 mm vs. 1.32 mm, p = 0.017), tibia AP distal (1.52 mm vs. 0.84 mm, p = 0.012), tibia lateral proximal (1.85 mm vs. 1.00 mm, p = 0.001), tibia lateral middle (2.36 mm vs. 1.03 mm, p < 0.001), and tibia lateral distal (2.34 mm vs. 0.85 mm, p < 0.001) levels. There were no significant differences between the two groups with respect to femoral tunnel widening and clinical outcomes. Conclusions: Tibial tunnel widening was significantly greater in the AL group than in the IF group at 2 years after primary ACLR. However, the clinical outcomes in the two groups were comparable at 2 years.

Arthroscopy-controlled medial reefing and lateral release for recurrent patellar dislocation: clinical, radiologic outcomes and complications.

BACKGROUND: Few studies have reported the clinical outcomes of the medial reefing procedure and lateral release with arthroscopic control of medial retinacular tension in patients with recurrent patellar dislocation. The purpose of this study was to investigate the clinical, radiologic outcomes and complications of arthroscopy-controlled medial reefing and lateral release. METHODS: Patients who underwent arthroscopy-controlled medial reefing and lateral release for recurrent patellar dislocation between November 2007 and June 2017 were retrospectively evaluated. The clinical outcome (Kujala score), radiologic outcome (congruence and patellar tilt angles), and complications were evaluated at final follow-up. The results were also compared with literature-reported outcomes of other surgical procedures for patellar dislocation. RESULTS: Twenty-five patients (mean age, 18.3 ± 4.8 years) were included in the study. The mean clinical follow-up period was 7.0 ± 2.5 (range, 3.8-12.2) years. The mean Kujala score was significantly improved from 54.7 ± 14.0 (range, 37-86) preoperatively to 91.0 ± 7.6 (range, 63-99) at a mean follow-up period of 7 years (P < 0.001). The radiologic results also significantly improved from 17.8° ± 5.9° to 6.8° ± 2.4° (P < 0.001) in the congruence angle and from 17.5° ± 8.2° to 5.6° ± 3.1° (P < 0.001) in the patella tilt angle at a mean follow-up period of 3.6 years. One patient developed a redislocation after a traumatic event, and two patients showed patellofemoral osteoarthritis progression. CONCLUSIONS: Arthroscopy-controlled medial reefing and lateral release significantly improved the clinical and radiologic outcomes of the patients with recurrent patellar dislocation at a mean follow-up period of 7 years. The results of this study are comparable with the literature-reported outcomes of other surgical procedures for patellar dislocation. LEVEL OF EVIDENCE: Level IV, retrospective therapeutic case series.

Preoperative Supine Radiographs Are More Accurate Than Standing Radiographs for Preoperative Planning in Medial Open-Wedge High Tibial Osteotomy.

PURPOSE: To verify the accuracy of supine nonweight-bearing radiography versus standing radiography in preoperative planning and to determine the predictors of unintended limb alignment correction in medial open-wedge high tibial osteotomy (OWHTO). METHODS: Consecutive patients who underwent medial OWHTO for medial osteoarthritis of the knee with varus alignment were retrospectively reviewed. The analyzed pre- and postoperative radiologic measurements included postoperative mechanical axis deviation (MAD) on standing whole-leg radiographs (WLRs), the predicted value of the postoperative MAD on the preoperative supine (predicted MADsupine) radiograph, and standing WLRs (predicted MADstand). Multiple linear regression analysis was used to identify variables predicting the postoperative MAD and unintended MADstand correction, defined as the difference between predicted MADstand and postoperative MAD. RESULTS: Predicted MADsupine showed statistically greater reliability in predicting postoperative MAD than predicted MADstand (intraclass correlation coefficient, 0.82 vs 0.45). Postoperative MAD was correlated with the predicted MADsupine and the difference in hip-knee-ankle angle between preoperative standing and supine WLRs (ΔHKA anglestand-supine) (R =763, R2 = 0.582, adjusted R2 = 0.569, P < .001) and did not differ significantly from the predicted MADsupine, with a mean difference of 0.28% ± 5.11% (P = .656). The mean unintended MADstand correction was 6.52% ± 8.66%. The difference in preoperative MAD between standing and supine WLRs was a significant predictor for unintended MADstand correction (ß = -0.350, P = .004). CONCLUSIONS: Preoperative planning with supine WLRs can predict postoperative limb alignment in medial OWHTO more accurately than standing radiographs. The clinical significance of the ΔHKA anglestand-supine for the risk of overestimation of postoperative limb alignment might be low because of the low power in the prediction model and small value of the ΔHKA anglestand-supine. Preoperative soft-tissue laxity was significantly correlated with unintended correction of postoperative limb alignment resulting from preoperative planning with standing radiographs. LEVEL OF EVIDENCE: Level IV, retrospective comparative study.

Supervised Rehabilitation May Lead to Better Outcome than Home-Based Rehabilitation Up to 1 Year after Anterior Cruciate Ligament Reconstruction.

Background and objectives: Previous studies consistently found no significant difference between supervised and home-based rehabilitation after anterior cruciate ligament reconstruction (ACLR). However, the function of the nonoperative knee, hamstring strength at deep flexion, and neuromuscular control have been overlooked. This prospective observational study was performed to investigate the outcomes after ACLR in operative and nonoperative knees between supervised and home-based rehabilitations. Materials and Methods: After surgery, instructional videos demonstrating the rehabilitation process and exercises were provided for the home-based rehabilitation group. The supervised rehabilitation group visited our sports medicine center and physical therapists followed up all patients during the entire duration of the study. Isokinetic muscle strength and neuromuscular control (acceleration time (AT) and overall stability index (OSI)) of both operative and nonoperative knees, as well as patient-reported knee function (Lysholm score), were measured and compared between the two groups 6 months and 1 year postoperatively. Results: The supervised rehabilitation group showed higher muscle strength of hamstring and quadriceps in nonoperative knees at 6 months (hamstring, p = 0.033; quadriceps, p = 0.045) and higher hamstring strength in operative and nonoperative knees at 1 year (operative knees, p = 0.035; nonoperative knees, p = 0.010) than the home-based rehabilitation group. At 6 months and 1 year, OSIs in operative and nonoperative knees were significantly better in the supervised rehabilitation group than in the home-based rehabilitation group (operative knees, p < 0.001, p < 0.001; nonoperative knees, p < 0.001, p < 0.001, at 6 months and 1 year, respectively). At 1 year, the supervised rehabilitation group also demonstrated faster AT of the hamstrings (operative knees, p = 0.016; nonoperative knees, p = 0.036). Lysholm scores gradually improved in both groups over 1 year; however, the supervised rehabilitation group showed higher scores at 1 year (87.3 ± 5.8 vs. 75.6 ± 15.1, p = 0.016). Conclusions: This study demonstrated that supervised rehabilitation may offer additional benefits in improving muscle strength, neuromuscular control, and patient-reported knee function compared with home-based rehabilitation up to 1 year after ACLR.

Complications Associated With Medial Opening-Wedge High Tibial Osteotomy Using a Locking Plate: A Multicenter Study.

BACKGROUND: The aim of this study is to investigate complications following medial opening-wedge high tibial osteotomy using a locking plate. In addition, we aimed to compare postoperative outcomes between the complicated and the uncomplicated group. METHODS: This study enrolled 209 patients who underwent medial opening-wedge high tibial osteotomy between 2010 and 2015. Patients with a follow-up period of at least 2 years were enrolled. Medical records and radiologic data were retrospectively reviewed. The complications were assessed up to postoperative 2 years and categorized into major and minor complications. The preoperative and postoperative clinical statuses were assessed using the Western Ontario McMaster University Osteoarthritis Index. RESULTS: The mean patient age was 56.4 ± 5.9 years. Overall complication rate was 29.7%. Minor complications included undisplaced lateral hinge fracture (12.0%), hardware irritation (1.4%), displaced lateral hinge fracture (2.4%), delayed wound healing (1.9%), undisplaced lateral tibial plateau fracture (1%), and superficial wound infection (1%). Major complications were symptomatic hardware which needed hardware removal (4.8%), deep wound infection (1.9%), hardware failure with correction loss (1%), nonunion (0.5%), and early conversion to arthroplasty (0.5%). Most complications occurred intraoperatively (30.6%) and within 3 months postoperatively (40.3%). The major complication group showed a statistically higher Western Ontario McMaster University Osteoarthritis Index score than did other groups at postoperative 1 year (P = .013) and 2 years (P = .001). CONCLUSION: The overall complication rate was 29.7%. Most complications were minor. The most common complication was undisplaced lateral hinge fracture. Major complications occurred in 8.6%. The major complication group showed significantly worse clinical outcomes than did the uncomplicated and minor complication groups.

Regeneration of lateral discoid meniscus after arthroscopic partial meniscectomy in an adult patient.

Arthroscopic partial resection is indicated for patients who have symptomatic discoid meniscus with overall satisfactory clinical outcomes. Reports regarding regeneration of discoid meniscus after arthroscopic surgery are limited. There are only two reports for children in the literature. To the authors' knowledge, the present study is the first report in the literature to report regeneration of discoid lateral meniscus after arthroscopic partial meniscectomy in an adult patient. The diagnosis was confirmed by both magnetic resonance imaging and arthroscopy. Surgeons should be aware that regeneration of discoid meniscus can occur in adult as well as pediatric patients.Level of evidence V.

Hamstring autograft maturation is superior to tibialis allograft following anatomic single-bundle anterior cruciate ligament reconstruction.

PURPOSE: Using second-look arthroscopy, graft maturation was investigated and compared between hamstring (HA) autografts and tibialis anterior (TA) allografts after anatomic single-bundle anterior cruciate ligament reconstruction (ACLR). METHODS: Fifty-six patients who underwent second-look arthroscopy after anatomic single-bundle ACLR with either HA autografts (26, HA group) or TA allografts (30, TA group) from 2007 to 2016 were retrospectively reviewed. Graft maturation on second-look arthroscopy was evaluated in terms of four parameters: graft integrity (tear), synovial coverage, graft tension, and graft vascularization. Each parameter received a maximum of two points, depending on the status of the reconstructed graft. The total graft maturation score was calculated as the sum of the parameter scores. The total graft maturation and individual parameter scores were compared between the two groups. RESULTS: The mean time from ACLR to second-look arthroscopy was 22.5 ± 7.8 months. The maturation scores in the HA group were significantly better in terms of graft integrity (p = 0.041), graft tension (p = 0.010), and graft vascularization (p = 0.024), whereas the graft synovial coverage score was not significantly different. The total graft maturation score of the HA group was significantly higher than that of the TA group (6.3 ± 0.4 vs. 4.9 ± 0.3, p = 0.013). CONCLUSIONS: This study shows the superior graft maturation of HA autografts compared with that of TA allografts at a mean follow-up of 22.5 ± 7.8 months after anatomic single-bundle ACLR. When anatomic ACLR using soft tissue graft is planned, HA autograft is recommended rather than soft tissue allograft, especially in young and active patients. LEVEL OF EVIDENCE: Retrospective cohort review, Level III.

Patient-reported outcomes correlate with functional scores after opening-wedge high tibial osteotomy: a clinical study.

PURPOSE: The purpose of this study was to assess post-operative patient subjective satisfaction and to analyze associated peri-operative factors following biplanar medial open wedge high tibial osteotomy (OWHTO). METHODS: The study cohort consisted of 88 patients with a minimum of two years of follow-up. Patient satisfaction was evaluated with a questionnaire that assessed (1) overall satisfaction, (2) pain relief, (3) daily living functions, and (4) cosmesis. Patients were categorized into two groups (satisfied or unsatisfied) based on overall satisfaction questionnaire. Pre- and post-operative objective clinical statuses were assessed with a knee scoring system based on the American Knee Society (AKS), the Western Ontario McMaster University Osteoarthritis Index (WOMAC), and range of motion. RESULTS: Of the 88 patients, 85.2% were graded as satisfied according to the overall satisfaction estimation. The percentage of patients satisfied with pain relief, daily living functions, and cosmesis were 85.2%, 86.4%, and 86.4%, respectively. Multivariable logistic regression analysis demonstrated that pre-operative Hip-Knee-Ankle angle (HKAA) (odds ratio (OR) = 1.812), post-operative AKS knee score (OR = 1.156), and post-operative HKAA (OR = 0.717) were significantly associated with overall satisfaction. Pre-operative HKAA (OR = 1.436), post-operative WOMAC activity score (OR = 0.865), and post-operative HKAA (OR = 0.505) were significant predictors for satisfaction with pain reduction, daily living functions, and cosmesis, respectively. CONCLUSIONS: Biplanar medial OWHTO is an effective treatment for osteoarthritis with varus deformity in terms of subjective satisfactory outcome. Several factors, including pre- and post-operative HKAA, post-operative AKS and WOMAC score, were significant predictors for subjective satisfaction. LEVEL OF EVIDENCE: Level III.

What Factors Are Associated With Femoral Component Internal Rotation in TKA Using the Gap Balancing Technique?

BACKGROUND: When using the gap-balancing technique for TKA, excessive medial release and varus proximal tibial resection can be associated with internal rotation of the femoral component. Previous studies have evaluated the causes of femoral component rotational alignment with a separate factor analysis using unadjusted statistical methods, which might result in treatment effects being attributed to confounding variables. QUESTIONS/PURPOSES: (1) What pre- and intraoperative factors are associated with internal rotation of the femoral component in TKA using the gap balancing technique? (2) To what degree does femoral component rotation as defined by the navigation system differ from rotation as measured by postoperative CT? METHODS: Three hundred seventy-seven knees that underwent computer-assisted primary TKA attributable to degenerative osteoarthritis with varus or mild valgus alignment in which medial soft tissue release was performed, and those with preoperative radiographs including preoperative CT between October 2007 and June 2014 were included in the study. To achieve a balanced mediolateral gap, the structures released during each medial release step were as follows: Step 1, deep medial collateral ligament (MCL); Step 2, superficial MCL (proximal, above the pes anserine tendon) and semimembranosus tendon; and Step 3, the superficial MCL (distal, below the pes anserine tendon). Knees with internal rotation of the femoral component, which was directed by navigation, to achieve a rectangular mediolateral flexion gap were considered cases, and knees without internally rotated femoral components were considered controls. Univariable analysis of the variables (age, sex, BMI, operated side, preoperative hip-knee-ankle angle, preoperative medial proximal tibial angle, preoperative rotation degree of the clinical transepicondylar axis [TEA] relative to the posterior condylar axis [PCA], coronal angle of resected tibia, resection of the posterior cruciate ligament, type of prosthesis, and extent of medial release) of cases and controls was performed, followed by a multivariable logistic regression analysis on those factors where p equals 0.15 or less. For an evaluation of navigation error, 88 knees that underwent postoperative CT were analyzed. Postoperative CT scans were obtained for patients with unexplained pain or stiffness after the operations. Using the paired t-test and Pearson's correlation analysis, the postoperative TEA-PCA measured with postoperative CT was compared with theoretical TEA-PCA, which was calculated with preoperative TEA-PCA and actual femoral component rotation checked by the navigation system. RESULTS: After controlling for a relevant confounding variable such as postoperative hip-knee-ankle angle, we found that the extent of medial release (Step 1 as reference; Step 2: odds ratio [OR], 5.7, [95% CI, 2.2-15]; Step 3: OR, 22, [95% CI, 7.8-62], p < 0.001) was the only factor we identified that was associated with internal rotation of the femoral component. With the numbers available, we found no difference between the mean theoretical postoperative TEA-PCA and the postoperative TEA-PCA measured using postoperative CT (4.8° ± 2.7º versus 5.0° ± 2.3º; mean difference, 0.2° ± 1.5º; p = 0.160). CONCLUSIONS: Extent of medial release was the only factor we identified that was associated with internal rotation of the femoral component in gap-balancing TKA. To avoid internal rotation of the femoral component, we recommend a carefully subdivided medial-releasing technique, especially for the superficial MCL because once the superficial MCL has been completely released it cannot easily be restored. LEVEL OF EVIDENCE: Level III, therapeutic study.

Diagnostic Value of Synovial White Blood Cell Count and Serum C-Reactive Protein for Acute Periprosthetic Joint Infection After Knee Arthroplasty.

BACKGROUND: The diagnosis of periprosthetic joint infection (PJI) remains difficult, particularly in acute postoperative stage. The purpose of this study was to investigate the optimal cutoff value of synovial white blood cell (WBC) count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and C-reactive protein (CRP) for diagnosing early postoperative infection after knee joint arthroplasty. METHODS: We retrospectively reviewed primary total knee arthroplasties and unicompartmental knee arthroplasties, with a knee aspiration within 3 weeks of surgery, from January 2006 to November 2016. Twelve infected cases and 185 uninfected cases met the inclusion criteria of our study. We compared the laboratory parameters (synovial WBC count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and CRP levels) between the 2 groups. Receiver operating characteristic curves were constructed to determine the optimal cutoff values for each parameter. Each parameter was studied to determine its sensitivity, specificity, and positive and negative predictive values (PPV and NPV) in diagnosing acute PJI. RESULTS: There were 2 optimal cutoff values for synovial WBC count and CRP levels. With the cutoff value of synovial WBC set at 11,200 cells/µL, acute PJI could be diagnosed with the highest sensitivity (100%) and specificity (98.9%); with the cutoff value set at 16,000 cells/µL, the best PPV and NPV were found (100% and 99.5%, respectively). Similarly, the CRP level >34.9 mg/L had the best sensitivity (100%) and specificity (90.3%), whereas the CRP level >74.5 mg/L had the best PPV (100%) and NPV (99.2%). CONCLUSION: Synovial WBC count and CRP levels are useful in diagnosing acute PJI between 1 and 3 weeks after primary knee arthroplasty.

Intraoperative Fluoroscopic Assessment of Limb Alignment is a Reliable Predictor for Postoperative Limb Alignment in Biplanar Medial Opening-Wedge High Tibial Osteotomy.

BACKGROUND: The purpose of this study was to assess the reliability of pre-, intra operative, and postoperative limb alignment measurements and investigate the correlation between the measurements in biplanar medial opening-wedge high tibial osteotomy. METHODS: This study enrolled 59 knees undergoing biplanar opening-wedge high tibial osteotomy for primary medial osteoarthritis with varus deformity. Preoperative and postoperative standing lower leg radiographs and intraoperative fluoroscopic images were taken. Two independent examiners analyzed the radiologic data to assess lower limb alignment and mechanical axis (MA) deviation (percentage of MA position on tibial plateau). The effect of preoperative hip-knee-ankle angle and MA deviation, age, sex, body mass index (BMI), and joint line convergence angle on the discrepancy between intraoperative and postoperative MA deviation was analyzed. RESULTS: The mean preoperative hip-knee-ankle angle and MA deviation were varus 7.7 ± 3.3° and 14.1 ± 15.1%, respectively. After osteotomy, the mean intraoperative postosteotomy MA deviation was 57.9 ± 2.1% in supine position, and the mean post-operative MA deviation increased to 63.9 ± 2.9% on standing radiographs. The mean difference between intraoperative postosteotomy MA deviation and postoperative MA deviation was 6.1 ± 2.2%. Linear regression analysis between intraoperative postosteotomy MA deviation and postoperative MA deviation showed a statistically significant linear relationship (R2 = 0.449; P < .001). Multivariate regression analysis revealed that preoperative joint line convergence angle (ß = 0.856; P < .001) and BMI (ß = 0.349; P < .001) were significant positive predictors for the difference in MA deviation. CONCLUSION: There was a significant linear relationship between intraoperative postosteotomy MA deviation and postoperative MA deviation following biplanar medial opening-wedge high tibial osteotomy. A greater discrepancy between MA deviations was significantly associated with higher BMI and joint line convergence angle.