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.

Differences in age-related characteristics among elderly patients with hip fractures.

BACKGROUND: Incidence of hip fracture among aging patients has been increasing annually in Japan; patients aged ≤74 years may be inappropriately classified as elderly. This study aimed to identify differences in the incidence of serious perioperative complications and in-hospital, 90-day, 6-month, and 1-year mortality rates according to three age groups among patients with hip fractures. METHODS: Patients aged ≥65 years treated for hip fracture by our multidisciplinary treatment system were included in this study. They were divided into the pre-old age (65-74 years), old age (75-89 years), and super-old age (≥90 years) groups. The baseline characteristics and outcomes of the three groups were compared, and variables associated with in-hospital, 30-day, 6-month, and 1-year mortality were analyzed. RESULTS: In the older population, there was a higher proportion of female participants; those with trochanteric fractures, low bone mineral density, dementia, decreased walking ability and independence in performing activities of daily living; and those not living at home. Moreover, the proportion of patients with hypertension, diabetes mellitus, and circulatory disorders, American Society of Anesthesiologists Physical Status scores, and serum albumin levels significantly differed. Further, there was a significant difference in the incidence of serious complications among males and the 6-month and 1-year mortality rates among females. In addition, female patients in the pre-old age group had a higher mortality rate at any period compared with those in the old age group. CONCLUSIONS: Patients with hip fracture who were aged 65-74, 75-89, and ≥90 years differ in terms of baseline characteristics, incidence of complications, and mortality rates. Female patients aged<75 who had fragility hip fractures potentially had worse prognosis. Our findings may be useful in preoperative explanation, postoperative management, and prognostic prediction.

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.

Postoperative Urinary Retention in Japanese Elderly Males with a Femoral Neck or Trochanteric Fracture.

We assessed risk factors for postoperative urinary retention (UR) in elderly males with femoral bone fractures: 169 Japanese males (mean age 81.95 ± 1.19 years) who had undergone hip surgery at a municipal hospital (Toyama, Japan). A multiple logistic regression analysis was used to test possible risk factors for UR: age, body mass index, serum albumin, cognitive impairment, activities of daily living (ADL), and history of diabetes mellitus (DM). UR occurred in 24 (14.2%) of the 169 patients. A multivariate logistic regression analysis with age adjustment showed that ADL (odds ratio [OR] 3.88; 95% confidence interval [CI]: 1.2-12.5, p=0.023) was significantly associated with the development of UR, and a history of DM showed marginal significance for UR occurrence (OR 0.36, 95%CI: 0.11-10, p=0.064). These results suggests that ADL is a risk factor for UR development in elderly males who have undergone surgery for femoral neck or trochanter fractures.

Orthogeriatric co-management at a regional core hospital as a new multidisciplinary approach in Japanese hip fracture operation.

BACKGROUND: This study aimed to evaluate the effects of orthogeriatric co-management of hip fractures at a regional core hospital. METHODS: This study included patients with proximal hip fracture. Patients were divided into two groups, conventional multidisciplinary group I including patients attending the hospital between April 2015 and March 2016 and orthogeriatric group II including patients attending the hospital between April 2016 and March 2017, which were compared etrospectively. In the control group, the conventional multidisciplinary team treated patients as whole-body controls. In the intervention group, the newly recruited geriatricians performed physical examinations, laboratory tests, radioactive imaging, and physiological tests. Furthermore, they consulted ward pharmacists, rigorously conducted positive polypharmacy interventions , and evaluated the type and number of mediated drugs on admission. RESULTS: The number of medicated drugs significantly decreased from 6.03 ± 4.3 on admission to 5.50 ± 3.59 on discharge in group II, whereas group I did not show a significant decrease. Despite the more number of hospitalized patients in group II (166 patients) than in group I (126 patients), the recovery rate from postoperative urinary retention increased significantly from 57.8% (19/30) in group I to 84.3% (32/59) in group II (p = 0.049), while the incidence of aspiration pneumonia decreased from 7.1% (9/126) in group I to 2.49% (4/166) in group II (p = 0.08). The patients received six or more prescribed drugs on admission, and the number remained constant. However, the number of medicated drugs on discharge showed a marginally significant decrease from 6.03 ± 4.3 in group I to 5.50 ± 3.59 in group II (p < 0.05). CONCLUSIONS: Compared to the conventional multidisciplinary group, the orthogeriatric team contributed to reducing the number of multi-effect drugs and perioperative complications without negatively affecting mortality despite the increased number of patients. The in-hospital mortality rate did not change between the groups. The orthogeriatric program succeeded in preventing and treating perioperative complications.

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.

Asymmetry of the pelvic ring evaluated by CT-based 3D statistical modeling.

The human pelvis is a complex anatomical structure that consists of the innominate bones, sacrum and coccyx to form the pelvic ring. Even though considered to be a symmetric entity, asymmetry of the pelvic ring (APR) might occur to alter its anatomy, function, or biomechanics or to impact assessment and treatment of clinical cases. APR and its assessment is complicated by the intricate anatomy of the pelvic ring. There is only limited information and understanding about APR with no established evaluation methods existing. The objective of the present study was to adopt CT-based 3D statistical modeling and analysis to assess APR within the complex anatomy of the pelvic ring. We were interested to establish a better understanding of APR with knowledge and applications transferred to human anatomy, related research, and development subjects and to clinical settings. A series of 150 routine, clinical, pelvic CT protocols of European and Asian males and females (64 ± 15 (20-90) years old) were post-processed to compute gender- and ancestry-specific 3D statistical models of the pelvic ring. Evaluations comprised principal component analysis (PCA) that included size, shape, and asymmetry patterns and their variations to be assessed. Four different CT-based 3D statistical models of the entire pelvic ring were computed according to the gender and ancestry specific groups. PCA mainly displayed size and shape variations. Examination of additional PCA modes permitted six distinct asymmetry patterns to be identified. They were located at the sacrum, iliac crest, pelvic brim, pubic symphysis, inferior pubic ramus, and near to the acetabulum. Accordingly, the pelvic ring demonstrated not to be entirely symmetric. Assessment of its asymmetry proved to be a challenging task. Using CT-based 3D statistical modeling and PCA, we identified six distinct APRs that were located at different anatomical regions. These regions are more prone to APRs than other sites. Minor asymmetry patterns have to be distinguished from the distinct APRs. Side differences with regard to size, shape, and/or position require to be taken into account. APRs may be due different load mechanisms applied via spine or lower extremity or locally. There is a need for simpler and efficient, yet reliable methods to be routinely transferred to human anatomy, related research, and development subjects and to clinical settings.

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.

3D statistical model of the pelvic ring - a CT-based statistical evaluation of anatomical variation.

The pelvic ring is a highly complex construct with a central role for human stability and mobility. The observable interindividual differences in skeletal anatomy are caused by anatomical variation in the innominate bones as well as the sacrum, further to differences in the spatial arrangement of these bones to each other. The aim of this study was to generate a 3D statistical model of the entire pelvic ring in order to analyse the observed interindividual differences and anatomical variation. A series of 50 anonymized pelvic CT scans of uninjured Japanese adults [30 males, 20 females, average age of 74.9 years, standard deviation (SD) 16.9 years] were processed and analysed, resulting in a 3D statistical overall mean model and separate male and female mean models. Principal component analysis (PCA) of the overall statistical model predominantly showed size variation (20.39%) followed by shape variation (14.13%), and a variation of the spatial arrangement of the sacrum to the innominate bones in different anatomical peculiarities (11.39 and 8.85%). In addition, selected internal and external pelvic parameters were manually measured with the objective of further evaluating and quantifying the observed interindividual as well as the known sex-specific differences. A separate statistical model of the grey value distribution based on the given Hounsfield unit (HU) values was calculated for assessing bone mass distribution, thus an indication of bone quality utilizing grey values as a quantitative description of radiodensity was obtained. A consistent pattern of grey value distribution was shown, with the highest grey values observed between the sacro-iliac joint and the acetabulum along the pelvic brim. Low values were present in the sacral ala, in the area of the iliac fossa as well as in the pubic rami next to the symphysis. The present model allows a differentiated analysis of the observed interindividual variation of the pelvic ring and an evaluation of the grey value distribution therein. Besides providing a better understanding of anatomical variation, this model could be also used as a helpful tool for educational purposes, preoperative planning and implant design.

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.

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.

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.

The effect of a multidisciplinary approach on geriatric hip fractures in Japan.

BACKGROUND: This study aimed to report results of the multidisciplinary treatment approach for geriatric hip fractures and evaluate its effectiveness compared with conventional treatment. Patients aged 65 years and older who presented with a hip fracture at our hospital on or after 2014 were treated according to a multidisciplinary approach. METHOD: Two groups of patients with hip fracture were compared. Group I (n = 364) was treated according to the new multidisciplinary approach in 2014-2016, and Group II (n = 105) which received conventional treatment in 2012. Time to surgery, length of hospital stay, postoperative complications, osteoporosis treatment, functional recovery, in-hospital mortality, 90-day mortality, and 1-year mortality were evaluated. The medical costs of multidisciplinary treatment were compared with those in other hospitals every year. RESULTS: There were no significant differences in the time to surgery between Group I and Group II, but each was considerably shorter than the average time in other Japanese hospitals. The length of hospital stay was longer in Group I. The overall postoperative complication rate was lower in Group I, but there was no significant difference for each individual complication. The rate of anti-osteoporosis pharmacotherapy administration at the time of discharge was significantly higher in Group I. Moreover, the proportion of patients who recovered to their pre-injury functional level was significantly higher in Group I. The mortality rates did not significantly differ year on year. The total hospitalization medical cost per patient for the multidisciplinary treatment was lower than other hospital costs every year. CONCLUSIONS: Multidisciplinary treatment produced no significant improvement in time to surgery, length of hospital stay, or postoperative complications. However, the use of the multidisciplinary treatment approach led to a significant increase in osteoporosis treatment rate and better functional recovery. Furthermore, the total medical costs for multidisciplinary treatment were lower than the acute care hospital costs.

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.

Space available for trans-sacral implants to treat fractures of the pelvis assessed by virtual implant positioning.

INTRODUCTION: The use of trans-sacral implants to treat fractures of the sacrum is limited by the variable pelvic anatomy. We were interested in how many trans-sacral implants can be placed per pelvis? If a trans-sacral implant cannot be placed in S1, where is the cortex perforated, and is the use of sacroiliac screws safe in these pelves? MATERIALS AND METHODS: 3D pelvic models were created from CT scans of 156 individuals without fractures (92 European and 64 Japanese, 79 male and 77 female, mean age 66.7 ± 13.7 years). Trans-sacral implants with a diameter of 7.3 mm were positioned virtually with and without a surrounding safe zone of 12 mm diameter. RESULTS: Fifty-one percent of pelves accommodated trans-sacral implants in S1 with a safe zone. Twenty-two percent did not offer enough space in S1 for an implant even when ignoring the safe zone. Every pelvis had sufficient space for a trans-sacral implant in S2, in 78% including a safe zone as well. In S1, implant perforation was observed in the sacral ala and iliac fossa in 69%, isolated iliac fossa perforation in 23% and perforation of the sacral ala in 8%. Bilateral sacroiliac screw placement was always possible in S1. CONCLUSIONS: The use of trans-sacral implants in S1 requires meticulous preoperative planning to avoid injury of neurovascular structures. S2 more consistently offers space for trans-sacral implants.

Fragility fractures of the sacrum occur in elderly patients with severe loss of sacral bone mass.

INTRODUCTION: Patients suffering from osteoporosis-associated fragility fractures of the sacrum (FFS; also termed sacral insufficiency fractures) are increasingly observed. They have typical fracture patterns with fracture lines located in the sacral ala. When treating these patients operatively, iliosacral screw loosening is not uncommon. We aimed to study the sacral bone mass in patients presenting with a FFS using 3D statistical models. MATERIALS AND METHODS: 3D models of averaged Hounsfield units (HU) were generated based on CT scans from 13 patients with a unilateral FFS (mean age 79.6 years; 11 females, 2 males). The control group without fractures consisted of 28 males and 32 females (mean age of 68.3 years). A virtual bone probe along the trans-sacral corridors S1 and S2 was taken. RESULTS: The bone mass distribution in the fractured sacra was similar to the control group, however, with overall lower HU. Large zones of negative HU were located in the sacral ala. In the fractured sacra, the HU in the sacral ala was significantly lower on the non-injured side when comparing to the fractured side (p < 0.001) as well as compared to the non-fractured group (p < 0.001). Low bone mass was observed in sacral body S1 (40 HU) and S2 (20 HU). CONCLUSIONS: The extensive area of negative HU may explain the fracture location in the sacral ala. The low HU in the sacral bodies advocates the use of trans-sacral implants or augmented iliosacral screws to enhance the strength of fracture fixation. The increased HU in the fractured ala could be explained by fracture-asssociated hemorrhage and can be used as a diagnostic tool.

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.

Age does not affect the clinical and radiological outcomes after open-wedge high tibial osteotomy.

PURPOSE: Open-wedge high tibial osteotomy (OWHTO) is a well-established procedure in the management of medial compartment osteoarthritis and osteonecrosis of the medial femoral condyle. Several studies have evaluated factors that negatively influence outcomes. However, few reports have investigated the effect of age on HTO outcome. We evaluated the influence of the age on the outcome after HTO. METHODS: The TomoFix® plate was used to perform 60 consecutive OWHTOs. Twenty-six knees in 23 patients >65 years old (mean age at surgery 68.7 ± 2.9 years; range 65-75 years, group A) were compared with 34 knees in 27 patients <65 years old (mean age at surgery 56.2 ± 7.5 years; range 38-64 years, group B) with respect to the clinical and radiological outcomes after HTO. The clinical evaluation included the Japanese Orthopedic Association Knee Score (JOA score), Oxford Knee Score (OKS) and complications after surgery. RESULTS: There were no statistical differences in the background factors between the two groups. Postoperatively, the mean JOA score showed a significant improvement in both groups. The mean OKS after surgery was 41.6 ± 5.9 in group A and 41.4 ± 5.9 in group B. There were no statistical differences in the postoperative knee alignment and clinical outcomes between the two groups. CONCLUSION: OWHTO using the rigid long plate was an effective procedure independent of patient's age. The results showed that age did not influence the clinical and radiological outcomes after OWHTO.

Responsiveness of the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Oxford Knee Score (OKS) in Japanese patients with high tibial osteotomy.

BACKGROUND: To assess responsiveness of the Japanese Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Oxford Knee Score (OKS) in patients undergoing open-wedge HTO to treat knee osteoarthritis and/or osteonecrosis. METHODS: Patients completed a set of questionnaires before HTO surgery (baseline) and 1 year after surgery. The questionnaires comprised the validated Japanese versions of the KOOS, the OKS, and the SF-36v2 and a visual analogue scale (VAS) for local knee pain and general pain. The treating surgeon completed the Japanese Orthopedic Association (JOA) score for osteoarthritic knees. The study included 119 patients aged 64.7 ± 8.3, 116 were followed at 1 year. 90 patients had knee osteoarthritis (OA) solely. 28 patients suffered from both OA and osteonecrosis (ON); one patient had ON only. Responsiveness to change was assessed using the effect size (ES) between the baseline and the 1-year postoperative assessment and standardized response mean. A distribution-based approach was used to determine the minimally detectable change (MDC95) for the KOOS subscales, and the OKS. RESULTS: All instruments demonstrated statistically significant changes between the preoperative assessments and one year after surgery. All changes showed an improvement in score, but the condition-specific measures revealed higher responsiveness than the generic measures. All KOOS subscales, the OKS, the local pain VAS, and the JOA score showed large ESs (ES > 1.24) and SRMs (SRM>1.04). At a 95% confidence level, the respective MDCs were 15.83, 18.94, 15.22, 18.99 and 17.23 for the KOOS-Pain, KOOS-Symptoms, KOOS-ADL, KOOS-Sport/Rec, and KOOS-QOL subscales, respectively. The MDC95 for the OKS was 8.29. CONCLUSIONS: Both, the KOOS and OKS are responsive for use in Japanese-speaking patients with knee osteoarthritis and/or osteonecrosis who are undergoing HTO.

Geriatric tibial plateau fractures: Clinical features and surgical outcomes.

BACKGROUND: Operative treatment of geriatric tibial plateau fractures is challenging and controversial. There are few studies focusing on the clinical features and operative outcomes of tibial plateau fractures in the elderly. Hence, this study aimed to investigate the clinical features and operative results of these fractures. METHODS: Thirty-three displaced tibial plateau fractures in patients >65 years old (mean age: 72.1 years, range: 65-94 years) were treated operatively. We investigated the mechanisms of injury, fracture types according to the Schatzker classification, incidences of soft tissue injury, and postoperative complications. Clinical and radiographic data were analyzed in 23 patients at the last follow-up. The mean follow-up period was 4.0 years (range: 1-13 years). Twenty-one patients were treated with open reduction and internal fixation and evaluated using the Rasmussen clinical and radiologic scores. Two patients with advanced osteoarthritis were treated primarily with total knee arthroplasty and assessed using the Japanese Orthopaedic Association score for the knee osteoarthritis. RESULTS: Twenty-four patients (72.7%) were injured by low-energy trauma such as a simple fall. Four patients had compartment syndrome and required fasciotomies. Rasmussen clinical and radiologic scores were satisfactory in 85.7% and 81.0% of patients, respectively. Two patients treated primarily with total knee arthroplasty showed no radiologic abnormality, and their Japanese Orthopaedic Association scores were both 70 points. CONCLUSIONS: Geriatric tibial plateau fractures, although mostly due to low-energy trauma, were often accompanied with severe comminution and compartment syndrome. Postoperative results of open reduction and internal fixation for this population were relatively good. Therefore, primary total knee arthroplasty should only be considered for well-selected patients.