Patellofemoral Osteoarthritis Progression After Open-Wedge High Tibial Osteotomy Does Not Affect the Clinical Outcomes or Survivorship at Minimum 7 Years' Follow-Up.

PURPOSE: To evaluate the clinical and radiologic outcomes of open-wedge high tibial osteotomy (OWHTO) with respect to the patellofemoral joint and to assess the effects of patellofemoral osteoarthritis (OA) progression after OWHTO on clinical outcomes at minimum 7 years' follow-up. METHODS: We retrospectively reviewed 95 knees that underwent OWHTO and at least 7 years of follow-up. Clinical parameters including anterior knee pain, Japanese Orthopedic Association score, Oxford Knee Score, Knee Injury and Osteoarthritis Outcome Score, Hospital for Special Surgery patella score, and Knee Injury and Osteoarthritis Outcome Score-patellofemoral subscale were evaluated. Radiologic outcomes were evaluated preoperatively and at final follow-up. Patellofemoral OA progressions were evaluated using Kellgren-Lawrence grade, and we divided the patients into 2 groups (progression group and non-progression group) to evaluate the effect of patellofemoral OA progression after OWHTO on long-term clinical outcomes. RESULTS: The mean follow-up period was 10.8 ± 2.6 years (range: 7.6-17.3 years). The mean Japanese Orthopedic Association score significantly improved (from 64.4 ± 11.6 to 90.9 ± 9.3, P < .001), and the mean Oxford Knee Score at final follow-up was 40.4 ± 8.3. Due to medial OA progression, 5 cases were converted to total knee arthroplasty, and the survival rate was 94.7% at 10.8 years of follow-up. Radiologically, patellofemoral OA progression was observed at final follow-up in 48 knees (50.5%). However, there were no significant differences in all clinical outcomes at final follow-up between the progression and non-progression groups. CONCLUSIONS: Patellofemoral OA progression may progress over long-term follow-up after OWHTO. Related symptoms are minimal and this does not affect the clinical outcomes or survivorships at minimum 7 years follow-up. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Influence of lateral hinge fractures on biplanar medial closing-wedge distal femoral osteotomy for valgus knee: a new classification of lateral hinge fracture.

BACKGROUND: The purpose of this study was to examine the influence of lateral hinge fractures in medial closing-wedge distal femoral osteotomy (MCWDFO) on bone union. METHODS: Twenty-one patients were followed-up for more than 1 year after MCWDFO. The incidence and type of hinge fracture, as well as the course of bone healing, were investigated. Slow healing was defined as bone union was not obtained until 3 months after surgery. RESULTS: Hinge fractures were observed in 12 cases (57%). There were three types of hinge fractures. Type 1: the lateral cortex was completely cut through (4 cases), type 2: the osteotomy line was too proximal (6 cases), and type 3: the hinge point was significantly medial (2 cases). There was a significant difference in the mean correction angles between hinge fracture and no-fracture cases, with the mean angles being 13.8 ± 4.0° and 9.6 ± 3.1°, respectively. Sixty-seven percent (8/12) of cases with hinge fractures developed slow healing. Among the hinge fracture cases, when there was no displacement of the hinge fracture and good contact with the anterior flange, 40% (2/5) of cases developed slow healing. If there was displacement of the hinge or no contact of the anterior flange, 86% (6/7) of cases developed slow healing. In contrast, only 11% (1/9) of subjects who did not have a hinge fracture, developed slow healing. In 67% (6/9) of cases with slow healing, a correction loss of 2° or greater (average: 4.3 degrees valgus) was observed. There were no cases of non-union. Clinical outcomes at 1 year showed no significant difference between the groups with and without hinge fractures. CONCLUSIONS: There is a very high risk of hinge fracture in patients undergoing MCWDFO. Hinge fractures often lead to slow healing and a loss of correction. We recommend the endpoint of the distal lateral cortex of the femur as the ideal hinge point for the prevention of hinge fractures. Bone union is obtained slowly in even all hinge fracture cases without revision surgery. Consequently, surgical results are not affected by the occurrence of hinge fracture at 1 year.

Low-intensity pulsed ultrasound does not promote bone healing and functional recovery after open wedge high tibial osteotomy.

AIMS: To evaluate whether low-intensity pulsed ultrasound (LIPUS) accelerates bone healing at osteotomy sites and promotes functional recovery after open-wedge high tibial osteotomy (OWHTO). METHODS: Overall, 90 patients who underwent OWHTO without bone grafting were enrolled in this nonrandomized retrospective study, and 45 patients treated with LIPUS were compared with 45 patients without LIPUS treatment in terms of bone healing and functional recovery postoperatively. Clinical evaluations, including the pain visual analogue scale (VAS) and Japanese Orthopaedic Association (JOA) score, were performed preoperatively as well as six weeks and three, six, and 12 months postoperatively. The progression rate of gap filling was evaluated using anteroposterior radiographs at six weeks and three, six, and 12 months postoperatively. RESULTS: The pain VAS and JOA scores significantly improved after OWHTO in both groups. Although the LIPUS group had better pain scores at six weeks and three months postoperatively, there were no significant differences in JOA score between the groups. The lateral hinge united at six weeks postoperatively in 34 (75.6%) knees in the control group and in 33 (73.3%) knees in the LIPUS group. The progression rates of gap filling in the LIPUS group were 8.0%, 15.0%, 27.2%, and 46.0% at six weeks and three, six, and 12 months postoperatively, respectively, whereas in the control group at the same time points they were 7.7%, 15.2%, 26.3%, and 44.0%, respectively. There were no significant differences in the progression rate of gap filling between the groups. CONCLUSION: The present study demonstrated that LIPUS did not promote bone healing and functional recovery after OWHTO with a locking plate. The routine use of LIPUS after OWHTO was not recommended from the results of our study. Cite this article: Bone Jt Open 2022;3(11):885-893.

Multidisciplinary care model for geriatric patients with hip fracture in Japan: 5-year experience.

INTRODUCTION: Japan is a super-aging society, the geriatric care system establishment for hip fractures is at an urgent task. This report described our concept of multidisciplinary care model for geriatric hip fractures and 5-year outcomes at the Toyama City Hospital, Japan. METHODS: In this retrospective cohort study, a multidisciplinary treatment approach was applied for elderly patients with hip fracture since 2014. These patients (n = 678, males: n = 143, mean age: 84.6 ± 7.5 years), were treated per the multidisciplinary care model. Time to surgery, length of hospital stays, complications, osteoporosis treatment, mortality, and medical costs were evaluated. RESULTS: The mean time to surgery was 1.7 days. Overall, 78.0% patients underwent surgery within 2 days. The mean duration of hospital stay was 21.0 ± 12.4 days. The most frequent complication was deep venous thrombosis (19.0%) followed by dysuria (14.5%). Severe complications were pneumonia 3.4%, heart failure 0.8% and pulmonary embolism 0.4%. The in-hospital mortality rate was 1.2%. The 90-day, 6-month, and 1-year mortality rates were 2.5%, 6.7%, and 12.6%, respectively. The pharmacotherapy rate for osteoporosis at discharge was 90.7%, and the continuation pharmacotherapy rate was 84.7% at 1-year follow-up. The total hospitalization medical cost per person was lower than about 400 other hospitals' average costs every year, totaled 14% less during the 5-year study period. CONCLUSION: We have organized a multidisciplinary team approach for geriatric hip fracture. This approach resulted in a shorter time to surgery and hospital stay than the national average. The incidence of severe complications and mortality was low. The multidisciplinary treatment has maintained a high rate of osteoporosis treatment after discharge and at follow-up. Furthermore, the total medical cost per person was less than the national average. Thus, the multidisciplinary treatment approach for geriatric hip fractures was effective and feasible to conduct in Japan.

Factors Associated With Patient Satisfaction After Opening-Wedge High Tibial Osteotomy.

BACKGROUND: Opening-wedge high tibial osteotomy (OWHTO) is expected to result in higher patient satisfaction compared with knee arthroplasty due to joint preservation. However, patient satisfaction rates as well as factors associated with satisfaction after OWHTO remain unclear. PURPOSE: To evaluate patient subjective satisfaction after OWHTO and determine factors associated with patient satisfaction after OWHTO. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: This study enrolled 123 patients (123 knees) who underwent unilateral OWHTO. Clinical parameters, including range of motion (ROM), visual analog scale (VAS) score for pain, Knee injury and Osteoarthritis Outcome Score (KOOS), weightbearing line ratio (WBLR), and medial proximal tibial angle (MPTA), were assessed before surgery and at the final follow-up at a minimum of 2 years. Patient satisfaction was evaluated using a 5-point scale regarding (1) surgery, (2) pain relief, (3) knee mobility, (4) daily living function, and (5) lower extremity alignment. The mean overall satisfaction scores for the 5 questions were calculated, and the sample was divided into 2 main groups (satisfied or unsatisfied). Preoperative characteristics, physical activity level, patient expectations for surgery, ROM, and KOOS were compared between the groups. Cartilage regeneration was assessed at the time of plate removal, and WBLR and MPTA were also assessed. Factors associated with patient satisfaction were analyzed using multivariable logistic regression analysis. RESULTS: The mean ± SD follow-up was 54.6 ± 20.6 months. The mean WBLR significantly changed from 20.7% ± 11.8% preoperatively to 66.9% ± 10.2% at the final follow-up, and all KOOS subscale scores significantly improved after surgery. Of the 123 patients, 109 (88.6%) were graded as satisfied. Factors associated with patient satisfaction were expectations met (odds ratio, 17.4; P = .026), better postoperative KOOS Pain score (odds ratio, 1.30; P = .001), and better postoperative KOOS Activities of Daily Living score (odds ratio, 1.36; P = .002). CONCLUSION: OWHTO is an effective treatment in terms of subjective satisfactory outcomes. Patient expectations for surgery have a significant effect on patient satisfaction. Surgeons should consider patient expectations before OWHTO and provide patient education to improve patient satisfaction.

Open-wedge high tibial osteotomy for spontaneous osteonecrosis of the medial tibial plateau shows excellent clinical outcomes.

PurposeThere have been few reports on medial tibial plateau osteonecrosis, and treatment options remain controversial. This study aimed to evaluate the clinical outcomes of open-wedge high tibial osteotomy (OWHTO) for osteonecrosis of the medal tibial plateau.MethodsPatients who underwent OWHTO for spontaneous osteonecrosis of the medial tibial plateau from November 2013 to September 2017 at our institution and followed up for at least 2 years after surgery were included in this study. Patients with history of alcohol abuse and corticosteroid therapy were excluded. Clinical evaluations, including the Japanese Orthopedic Association (JOA) score and the Oxford Knee Score (OKS), were measured preoperatively and at the final followup. Radiological evaluations included the weight-bearing line ratio (WBLR) and the lesion stage of the osteonecrosis according to Carpintero, Lotke, and the modified Ficat and Arlet classification. The area and size of the necrosis and the type of meniscus tear were also evaluated using preoperative magnetic resonance imaging (MRI). Additionally, cartilage regeneration was evaluated at plate removal.ResultsTwelve cases that underwent OWHTO for spontaneous osteonecrosis of the medial tibial plateau were enrolled. Eleven cases had isolated medial tibial osteonecrosis, and one case had both femoral and tibial osteonecrosis. The mean age was 59.6 ± 9.0 years, and the mean follow-up period was 41.8 ± 17.6 months.The WBLR significantly changed after OWHTO (24.0% ± 10.7% to 66.3% ± 6.7%, P < 0.001), and all clinical scores significantly improved after surgery: JOA score 63.3 ±12.3 to 95.0 ± 4.8, OKS 27.4 ± 7.8 to 42.6 ± 4.1, both 0.001. There were no adverse complications requiring additional surgery. The MRI findings revealed that all cases had meniscal lesions in addition to a necrotic lesion. Second-look arthroscopy was performed at plate removal in 11 cases, and cartilage regeneration was observed in 9/11 cases (81.8%).ConclusionsThis study's results demonstrated that OWHTO is an effective procedure for spontaneous osteonecrosis of the medial tibial plateau with respect to subjective and objective clinical outcomes.

Plate removal without loss of correction after open-wedge high tibial osteotomy is possible when posterior cortex bone union reaches osteotomy gap center even in incompletely filled gaps.

PURPOSE: The study aimed to evaluate the optimal timing for plate removal after open-wedge high tibial osteotomy (OWHTO) without loss of correction and to investigate risk factors for loss of correction after plate removal. The study presents the hypothesis that plate removal without loss of correction was possible when gap filling reached zone 2 (25-50%) on anteroposterior radiographs. METHODS: Ninety-one patients (101 knees) who underwent OWHTO using the TomoFix® plate were enrolled. Plate removal was performed at an average 16.4 ± 5.4 months after OWHTO. Clinical evaluation included plate-related symptoms, the Japanese Orthopedic Association Knee Score (JOA score), and Oxford Knee Score (OKS). Radiological outcomes, including the hip-knee-ankle angle (HKA), weight-bearing line ratio (WBLR), medial proximal tibial angle (MPTA), and posterior tibial slope (PTS), were evaluated preoperatively, at plate removal and at 1 year after plate removal. Computed tomography (CT) was performed at plate removal to evaluate the flange bone union, progression rates of gap filling, and posterior cortex bone union. In addition, the risk factors for loss of correction after plate removal were evaluated. RESULTS: At plate removal, 63 (62.4%) knees had plate-related symptoms (mild, 56 knees; moderate, 7 knees; severe, 0). After plate removal, the JOA score did not change, whereas OKS further improved; six knees developed loss of correction. On CT evaluation at plate removal, the flange bone union was achieved in all cases; the progression rates of gap filling and posterior cortex bone union were 47.0% ± 16.6% and 62.8% ± 16.5%, respectively. A posterior cortex union rate of < 43.3% was the only predictor for loss of correction after plate removal (odds ratio: 1.38, P < 0.01). CONCLUSIONS: Plate removal without loss of correction after OWHTO was possible when bone union of the posterior cortex reached the center of the osteotomy gap even in incompletely filled gaps. LEVEL OF EVIDENCE: Therapeutic case series, Level IV.

Comparison of Clinical and Radiologic Outcomes Between Normal and Overcorrected Medial Proximal Tibial Angle Groups After Open-Wedge High Tibial Osteotomy.

PURPOSE: To evaluate whether the overcorrected medial proximal tibial angle (MPTA) affects the clinical outcomes after open-wedge high tibial osteotomy (OWHTO) and to assess the correlation between knee joint line obliquity (KJLO) changes and the compensatory changes in the hip and ankle joints. METHODS: Consecutive patients who underwent OWHTO from July 2006 to August 2015 were included. Exclusion criteria were bilateral OWHTO and follow-up of <2 years. The patients were retrospectively divided into 2 groups according to postoperative MPTA; a normal group (MPTA <95°) and an overcorrected MPTA group (MPTA ≥95°). The groups were compared with respect to the clinical and radiologic outcomes after OWHTO. Clinical parameters, including Japanese Orthopedic Association (JOA) score, Oxford Knee Score (OKS), and Knee Injury and Osteoarthritis Outcome Score (KOOS), were evaluated. Radiologic outcomes, including the hip-knee-ankle angle (HKA), joint line convergence angle (JLCA), MPTA, KJLO, ankle joint line obliquity (AJLO), and hip abduction angle (HAA), were evaluated preoperatively and at the final follow-up. RESULTS: Ninety-four patients (normal group; n = 52, overcorrected group; n = 42) were included in this study. After OWTHO, the mean increases in HKA and MPTA were 11.0° ± 3.2° and 10.4° ± 2.7°, respectively, whereas the change in KJLO was only 3.7° ± 2.9°. The mean AJLO (4.3 ± 3.9 to -1.3 ± 3.3, P < .001) and HAA (3.7 ± 2.5 to -1.1 ± 2.3, P < .001) significantly decreased after OWHTO. The mean postoperative MPTA in the overcorrected group was 96.9° ± 1.5°, whereas the mean postoperative KJLO was only 3.1° ± 2.0°. No significant differences were noted in all clinical scores between the groups at the final follow-up. CONCLUSIONS: A certain degree of overcorrected MPTA (≥95°) did not affect the clinical outcomes after OWHTO because of compensatory changes in the hip and ankle joints. LEVEL OF EVIDENCE: Level Ⅲ, retrospective comparative study.

Long-term clinical results of the crosse de hockey procedure for recurrent patellar dislocation.

BACKGROUND: A gold standard procedure has not been established for recurrent patellar dislocation because of multifactorial etiologies. We have been performing crosse de hockey procedure, which is a combination of medial and anterior transfer of the tibial tuberosity, in our institution since 1993. This study aimed to investigate the long-term clinical results of this procedure. MATERIALS AND METHODS: A total of 19 patients (21 knees) underwent the crosse de hockey procedure for recurrent patellar dislocation. Of these patients, four were lost to follow-up. The remaining 17 knees in 15 patients (5 male and 10 female) were included in this study. The mean follow-up period was 13.2 years (range: 5-22.6 years). Clinical evaluation was performed using the Kujala score. Radiographic indicators, such as modified Insall-Salvati ratio, sulcus angle, congruence angle, tilting angle, lateral shift ratio, and the progression of patellofemoral osteoarthritis (OA), were measured. RESULTS: Positive apprehension sign and redislocation were not observed in any of the patients. The mean Kujala score was significantly improved from 36.5 ± 18.0 preoperatively to 92.6 ± 9.9 at the final follow-up. Definite OA (a grade 2 or more using the Iwano grading system) was not observed in the patellofemoral joint at the final follow-up. CONCLUSIONS: The crosse de hockey procedure showed satisfactory long-term clinical results for recurrent patellar dislocation. This procedure could prevent the progression of patellofemoral OA because of the unloading effect of the patellofemoral joint by anteromedial transfer of the tibial tuberosity.

The influence of pre-operative antiplatelet and anticoagulant agents on the outcomes in elderly patients undergoing early surgery for hip fracture.

BACKGROUND: Early surgery improves the prognosis of elderly patients with hip fractures. However, many patients take antiplatelet and anticoagulant therapies for comorbidities. This study compared perioperative outcomes and 1-year mortality rates with early surgery in elderly patients with hip fractures taking or not taking these agents preoperatively. METHODS: Among 418 patients undergoing surgery for hip fractures at our institution from 2014 to 2016, 266 patients over 65 years who had surgery within 48 hours of admission were enrolled. We excluded patients with high-energy injuries, multiple or pathological fractures, and patients undergoing osteosynthesis for femoral neck fractures. The study population was divided into those who underwent hemiarthroplasty for neck fractures and those who underwent osteosynthesis for trochanteric fractures. We also divided the population into patients receiving chronic anticoagulation therapy (medicated group: 19 hemiarthroplasty, 70 osteosynthesis) and patients not receiving anticoagulation therapy (non-medicated group: 47 hemiarthroplasty, 130 osteosynthesis). Comorbidities, intraoperative blood loss, estimated blood loss from admission to the first and seventh day after surgery, transfusions, length of stay, complications, and 1-year mortality rates were evaluated. RESULTS: Diabetes mellitus and cerebrovascular disorders were significantly more common in the medicated group for both surgery types. In the osteosynthesis group, estimated blood loss on the first day was 710 ml in the medicated group and 572 ml in the non-medicated group (P = 0.015). In the hemiarthroplasty group, corresponding values were 668 and 480 ml, respectively (P = 0.016). Estimated blood loss on the seventh day, complications, length of stay and 1-year mortality rate were not increased significantly. CONCLUSIONS: The medicated group had an increase in estimated blood loss on the first day. However, there was no significant increase in transfusions, complications and 1-year mortality rates. Early surgery for elderly patients with hip fractures is recommended, even for those taking antiplatelet and anticoagulant agents.

Assessment of unloading effects after open wedge high tibial osteotomy using quantitative bone scintigraphy.

INTRODUCTION: We evaluated changes in bone tracer uptake (BTU) in open wedge high tibial osteotomy (OWHTO) and determined if BTU correlates with clinical symptoms, postoperative alignment, or cartilage regeneration after OWHTO. MATERIALS AND METHODS: Seventy-five knees in 64 patients who underwent OWHTO for medial compartment osteoarthritis were enrolled in this retrospective study. All cases were assessed preoperatively and at plate removal using bone scintigraphy. Visual analog scale (VAS), Japanese Orthopedic Association (JOA) score, Oxford Knee Score (OKS), Knee Injury and Osteoarthritis Outcome Score (KOOS), and the weight-bearing line ratio (WBLR) were assessed preoperatively and at plate removal. In addition, cartilage regeneration was evaluated at plate removal. We assessed changes in BTU for the medial and lateral compartment after OWHTO and the correlations between BTU of the medial compartment and all other parameters were analyzed. RESULTS: Postoperatively, all outcome measures significantly improved: mean VAS 61.4 ± 18.3 to 9.5 ± 8.2, mean JOA score 65.1 ± 11.5 to 94.7 ± 6.0, mean OKS 29.4 ± 8.1 to 42.3 ± 4.1, mean KOOS 57.0 ± 14.3 to 83.7 ± 9.6, mean WBLR 22.8 ± 10.9 to 70.0 ± 9.4. Cartilage regeneration was observed in 53 knees (70.7%). BTU of the medial compartment significantly decreased after OWTHO, whereas no increased postoperative BTU was found in the lateral compartment. Postoperative BTU of the medial compartment significantly correlated with VAS, KOOS, and WBLR. No statistically significant associations were found between BTU and cartilage regeneration. CONCLUSIONS: OWHTO significantly decreased BTU of the medial compartment, which correlated with knee pain and postoperative mechanical alignment. Unloading effects of OWHTO led to pain relief after surgery, regardless of cartilage regeneration.

Large opening gaps, unstable hinge fractures, and osteotomy line below the safe zone cause delayed bone healing after open-wedge high tibial osteotomy.

PURPOSE: To evaluate bone formation in the osteotomy gap after open-wedge high tibial osteotomy (OWHTO), including after plate removal, and to investigate risk factors for delayed bone healing. METHODS: Ninety-three patients (102 knees) who underwent OWHTO without bone grafting were enrolled. The osteotomy gap was divided into the lateral hinge and the four zones on anteroposterior radiographs, and we defined the zone in which trabecular bone continuity could be observed as gap filling. Bone formation in the osteotomy gap was evaluated according to this definition at 3, 6, and 12 months postoperatively; at plate removal; and at the final follow-up (mean, 62.3 ± 30.2 months). We also investigated the risk factors for delayed bone healing. RESULTS: The lateral hinge united at 3 months postoperatively in 92 knees (90.2%). At 1 year postoperatively, 98 knees (96.1%) reached zone 1 and 92 knees (90.2%) reached zone 2. At plate removal, gap filling reached zone 2 in all cases and progressed further without loss of correction after plate removal. Opening width over 13.0 mm [odds ratio (OR): 1.61, P = 0.02], Takeuchi's classification type II lateral hinge fracture (OR: 20.4, P < 0.01), and osteotomy line below the safe zone (OR: 8.98, P < 0.01) significantly delayed bone formation after OWHTO. CONCLUSIONS: Gap filling progressed from lateral to medial after OWHTO without bone grafting and progressed further after plate removal. Large opening gaps, unstable hinge fractures, and osteotomy line below the safe zone cause delayed bone healing after OWHTO.

Patellofemoral Osteoarthritis Progression and Alignment Changes after Open-Wedge High Tibial Osteotomy Do Not Affect Clinical Outcomes at Mid-term Follow-up.

PURPOSE: To evaluate the clinical and radiological outcomes of open-wedge high tibial osteotomy (OWHTO) with respect to the patellofemoral joint and to assess whether patellofemoral osteoarthritis (OA) progression and alignment changes after OWHTO affect clinical outcomes. METHODS: Inclusion criteria were consecutive patients who underwent OWHTO from March 2005 to September 2013. Exclusion criteria were loss to follow-up within 2 years and absence of second-look arthroscopy findings at the time of plate removal. The clinical parameters, including anterior knee pain while climbing stairs, Japanese Orthopedic Association score, and Oxford Knee Score, were evaluated. Radiological outcomes, including weight-bearing line ratio, modified Blackburne-Peel ratio, posterior tibial slope, tilting angle, lateral shift ratio, and patellofemoral OA (Kellgren-Lawrence grade), were evaluated preoperatively and at the final follow-up. Cartilage status (International Cartilage Repair Society grade) was evaluated at the initial HTO and at plate removal. RESULTS: Fifty-three patients (60 knees) were included in this study. The mean follow-up was 58.2 ± 22.4 months. Two knees (3%) presented with mild anterior knee pain after OWHTO. The mean Japanese Orthopedic Association score (66.9 ± 11.2 to 91.2 ± 9.7) significantly improved (P < .001), and the mean Oxford Knee Score at the final follow-up was 42.0 ± 5.3. The mean modified Blackburne-Peel ratio (0.9 ± 0.1 to 0.7 ± 0.1, P < .001) and tilting angle (6.8 ± 3.7 to 5.6 ± 3.4, P = .033) significantly decreased after OWHTO, whereas no significant changes in posterior tibial slope (P = .511) and lateral shift ratio (P = .522) were observed. Radiologically, patellofemoral OA had progressed in 15 knees (27%), and arthroscopically patellofemoral cartilage degeneration had progressed in 27 knees (45%). However, there was no significant correlation between changes in patellofemoral alignment and clinical outcomes. CONCLUSIONS: Changes in patellofemoral alignment and patellofemoral OA progression did not affect the clinical outcomes of OWHTO at mid-term follow-up. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Quantitative analysis of the Trendelenburg test and invention of a modified method.

BACKGROUND: While the Trendelenburg test has been used for 120 years to detect hip abductor muscle weakness, the methodology has not been standardised. PURPOSES: This study undertook to quantitatively analyze the relation between abductor muscle activity and pelvic tilt angle in the Trendelenburg one-leg stance, examine the pitfalls associated with performing the T-test, and develop a modified method that will produce reliable results. METHODS: A convenience sample of 15 healthy males was asked to assume a one-leg stance in ten different postures, five with mild flexion on the unsupported side, and five with severe flexion. Trunk sway angle, pelvic tilt angle, and the pelvic on femur (POF) angle were measured for each posture. Statistical analysis was used to assess differences in hip abductor activity and public tilt angle between the control posture and the test postures. RESULTS: With minimum trunk sway, hip abductor muscle activity increases when the pelvis is elevated and decreases when it is dropped. With trunk sway toward the test side, abductor muscle activity decreased when the pelvis was elevated; with trunk sway toward the non-test side, muscle activity stayed approximately constant when the pelvis was dropped. CONCLUSIONS: Based on the results we developed a modified T-test methodology that would improve reliability. This test should be performed with minimum trunk sway and severe flexion on the non-test side. The assessment of muscle weakness is based on whether the patient can keep the single-leg standing posture when forced to elevate the pelvis, not simply on the pelvic drop. In future research, we will perform the modified T-test on patients with a suspected hip abductor deficiency, and assess the usefulness of the modified test.

The paracrine effect of adipose-derived stem cells inhibits osteoarthritis progression.

BACKGROUND: This study aimed to determine whether intra-articularly injected adipose-derived stem cells (ADSCs) inhibited articular cartilage degeneration during osteoarthritis (OA) development in a rabbit anterior cruciate ligament transection (ACLT) model. The paracrine effects of ADSCs on chondrocytes were investigated using a co-culture system. METHODS: ACLT was performed on both knee joints of 12 rabbits. ADSCs were isolated from the subcutaneous adipose tissue. ADSCs with hyaluronic acid were intra-articularly injected into the left knee, and hyaluronic acid was injected into the right knee. The knees were compared macroscopically, histologically, and immunohistochemically at 8 and 12 weeks. In addition, cell viability was determined using co-culture system of ADSCs and chondrocytes. RESULTS: Macroscopically, osteoarthritis progression was milder in the ADSC-treated knees than in the control knees 8 weeks after ACLT. Histologically, control knees showed obvious erosions in both the medial and lateral condyles at 8 weeks, while cartilage was predominantly retained in the ADSC-treated knees. At 12 weeks, the ADSC-treated knees showed a slight suppression of cartilage degeneration, unlike the control knees. Immunohistochemically, MMP-13 expression was less in the ADSC-treated cartilage than in the control knees. The cell viability of chondrocytes co-cultured with ADSCs was higher than that of chondrocytes cultured alone. TNF-alpha-induced apoptotic stimulation was similar between the two groups. CONCLUSIONS: Intra-articularly injected ADSCs inhibited cartilage degeneration progression by homing to the synovium and secreting a liquid factor having chondro-protective effects such as chondrocyte proliferation and cartilage matrix protection.

Three-dimensional kinetic simulation before and after rotational acetabular osteotomy.

BACKGROUND: Some reports indicate that one of major causes of clinical failure after periacetabular osteotomy is development of secondary femoroacetabular impingement (FAI). To assess the impact of range of motion (ROM) on the increase in FAI following rotational acetabular osteotomy (RAO), we performed FAI simulations before and after RAO. METHODS: We evaluated 12 hips that had undergone RAO (study group), and 12 normal hips (control group). The study group was evaluated before and after surgery. Morphological parameters were evaluated to assess acetabular coverage. The acetabular anteversion angle, anterior CE angle, alpha angle, and combined anteversion angle were also measured. Impingement simulations were performed using 3D-CT. The ROM which causes bone-to-bone impingement was evaluated in flexion (flex), abduction, external rotation at 0° flexion, and internal rotation at 90° flexion. The lesions caused by impingement were evaluated. RESULTS: Radiographic measurements indicated improved postoperative acetabular coverage in the study group. The crossover sign was recognized pre- and postoperatively in every case in the study group and in no cases in the control group. In the simulation study, flexion, abduction, and internal rotation at 90° flexion decreased postoperatively. Impingement occurred within 45° internal rotation at 90° flexion in two preoperative and nine postoperative cases. The impingement lesions were anterosuperior of the acetabulum in all cases. There were correlations between anterior CE angle, CE angle, acetabular anteversion angle, and hip flexion angle. There were also correlations between the anterior CE angle, combined anteversion angle, and angle of internal rotation at 90° flexion. CONCLUSIONS: In the postoperative simulation, there was a tendency to reduce the ROM in flexion, abduction, and internal rotation at 90° flexion due to impingement. Since there were more cases which caused impingement within 45° internal rotation at 90° flexion after RAO, we consider there is a potential for increased FAI after RAO.

The value of computed tomography based navigation in revision total hip arthroplasty.

PURPOSE: This study investigates the accuracy of a computed tomography (CT)-based navigation system for accurate acetabular component placement during revision total hip arthroplasty (THA). METHODS: We performed a retrospective review of 30 hips in 26 patients who underwent cementless revision THA using a CT-based navigation system; the control group consisted of 25 hips in 25 patients who underwent cementless primary THA using the same system. We analysed the deviation of anteversion and inclination angles among the pre-operative plan, intra-operative records from the navigation system and data from postoperative CT scans. RESULTS: There were no significant differences between groups (P < 0.05) in terms of mean deviation between pre-operative planning and postoperative measurements or between intraoperative records and postoperative measurements. CONCLUSION: CT-based navigation in revision THA is a useful tool that enables the surgeon to implant the acetabular component at the precise angle determined in pre-operative planning.

Strict component positioning is necessary in hip resurfacing.

BACKGROUND: Hip resurfacing arthroplasty has some advantages, including improved metal-on-metal articulation, a lower dislocation rate and preserved femoral bone. This procedure is a surgical option for younger and more active patients with osteoarthritis and osteonecrosis of the femoral head. Although there have been some reports about the efficacy of this technique, others report serious complications caused by metal debris. Additionally, femoral neck preservation adversely decreases the head-neck ratio and results in postoperative impingement. METHODS: We evaluated the range of motion after hip resurfacing with various component orientations and optimal component orientations to avoid postoperative impingement using computer simulations in 10 male patients with osteonecrosis. RESULTS: The mean ranges of motion in flexion, extension, abduction, adduction and internal rotation at 90° of flexion were 92.4° ± 13.8°, 25.7° ± 13.8°, 38.0° ± 11.1°, 29.1° ± 10.0° and 20.9° ± 11.5°, respectively. The oscillation angle in flexion and extension motion was 118.1° ± 10.3°. More than 100° of flexion was acquired in 79 of 240 simulations (32.9 %), and more than 20° extension was acquired in 142 simulations (59.2 %). Combined anteversion was significantly correlated with maximal flexion and extension angles. The component safe zone to fulfill the range of motion criteria varied among patients, and 4 of 10 patients had no safe zone. CONCLUSIONS: Postoperative impingement occurs relatively frequently in hip resurfacing because of preservation of the femoral neck and component malpositioning. The safe zone of the acetabular component to avoid postoperative impingement is very narrow. Greater care should be taken regarding patient selection, rigorous preoperative planning and accurate component positioning.

Does degree of the pelvic deformity affect the accuracy of computed tomography-based hip navigation?

Although some navigation systems have been used for improvement of component positioning, there have been few reports regarding cases of severe pelvic deformity. We performed a retrospective review of 25 cases of total hip arthroplasty with a computed tomography-based navigation system in patients with severe pelvic deformities and estimated acetabular component position and angle between severe deformity group and mild dysplastic group as a control. There were no significant differences in accuracy of navigation system between 2 groups in terms of 3-dimensional component position or angle. Accuracy of computed tomography-based hip navigation does not depend on the degree of pelvic deformity, and this system is also useful to identify acetabular orientation and for precise component implantation in cases of pelvic deformity.