Prevalence, development, and factors associated with cyst formation after meniscal repair with the all-inside suture device Abstract Purpose To investigate the prevalence of cyst formation after using all-inside meniscal repair device and analysed the risk factors associated with it. Methods Between August 2008 and September 2013, 51 menisci of 46 patients were included in the study, 46 menisci of which had concomitant anterior cruciate ligament (ACL) ruptures and had an ACL reconstruction. Magnetic resonance imaging (MRI) of the knee was performed at 3, 6, 12 and 24 months after meniscal surgery. The MRIs were assessed to detect the development of cysts encasing the suture anchors and to evaluate meniscal healing. Statistical analysis was performed using multiple regression analysis. Results Out of the 51 menisci examined, MRI revealed cysts in 15 menisci. Cysts were detected in 3 menisci at 6 months, in 9 menisci at 12 months, and in 3 menisci at 24 months after surgery. Only 3 patients (6.5%) were symptomatic, and cystectomy was performed in 2 of these patients and arthroscopic debridement in the other. Compared with using both the suture device and an inside-out suture repair, using the suture device alone was more likely to be associated with cyst development [odds ratio (OR), 12.04]. The medial meniscus was also significantly more likely to develop a cyst compared with the lateral meniscus (OR, 12.48). There was an increased outcome for the number of device use (P = 0.033). Though it was not statistically significant, the patients with anterior knee laxity (side-to-side difference > 3 mm using a knee arthrometer) were more likely to develop cysts than those without anterior knee laxity (P = 0.06). There were no significant differences between the remaining variables. Conclusions The prevalence of cyst formation around the suture implant was 29%, but most cases were not symptomatic. Significant risk factors for cyst formation included the use of a suture device alone, and a location in the medial meniscus. Level of evidence III.

Staphylococcal resistance profiles in deep infection following primary hip and knee arthroplasty: a study using the NJR dataset Abstract Introduction This study aimed to (1) report the rates of resistance against a variety of antibiotics for pure Staphylococcal infections, and (2) examine the impact of ALBC use at primary surgery has on resistance patterns for patients undergoing first-time revision of primary hip and knee arthroplasty for indication of infection. Materials and methods Data from the National Joint Registry database for England and Wales were linked to microbiology data held by Public Health England to identify a consecutive series of 258 primary hip and knee arthroplasties performed between April 2003 and January 2014 that went on to have a revision for Staphylococcal deep periprosthetic infection. Multivariate binary logistic regression was used to study predictors of microorganism resistance to a range of antimicrobials. Results After adjusting for patient and surgical factors, multivariate analysis showed the use of gentamicin-loaded bone cement at the primary surgery was associated with a significant increase in the risk of Staphylococcal gentamicin resistance (odds ratio 8.341, 95% CI 2.297–30.292, p = 0.001) and methicillin resistance (odds ratio 3.870, 95% CI 1.319–11.359, p = 0.014) at revision for infection. Conclusions Clinicians must anticipate the possibility of antibiotic resistance to ALBC utilised at primary surgery.

Histological score for degrees of severity in an implant-associated infection model in mice Abstract Introduction Several scores were introduced to diagnose and to classify osteomyelitis in practice. Mouse models are often used to study the pathophysiology of bone infection and to test therapeutic strategies. Aim of the present study was to design a score to diagnose and quantify implant-associated infection in a murine experimental model. Materials and methods Four independent parameters were developed: existence of callus, consolidation of the fracture, structural changes of the medullary cavity and number of bacteria. The score was assessed in a standardized implant-associated mouse model with 35 BALB/c-mice. The left femur was osteotomized, fixed by a titanium locking plate and infection was induced by inoculation of Staphylococcus aureus into the fracture gap. For the sham group, the procedure was performed without inoculation of bacteria. The score was assessed on days 7, 14 and 28. Each item of the score showed lower values for the infection group compared to the controls after 4 weeks. Results Regardless of the assessed time point, the overall total score was significantly higher in the control group compared to the infection group (p < 0.0001). Analysis revealed a sensitivity of 0.85, specificity of 1.0, negative predictive value of 0.67 and positive predictive value of 1.0. Conclusion The proposed score assessing severity of fracture-related infection in an implant-associated murine model was easy to access, feasible to diagnose and estimate bone healing and infection in a murine bone infection with a high sensitivity. Therefore, this score might be a useful tool to quantify infection-related changes after fracture in further future preclinical studies.

Kellgren–Lawrence scoring system underestimates cartilage damage when indicating TKA: preoperative radiograph versus intraoperative photograph Abstract Introduction The Kellgren–Lawrence score helps the orthopedic surgeon to classify the severity of knee osteoarthritis (OA) before total knee arthroplasty (TKA). There might be a discrepancy between subjective complaints of the patients and radiologically visible changes of the knee joint in many cases. In this context, we performed a prospective clinical study to compare the preoperative degree of knee OA using the Kellgren–Lawrence score with the intraoperative extent of cartilage damage during primary TKA. Materials and methods A total of 251 primary TKA surgeries due to a primary knee OA were prospectively included. Preoperative Kellgren–Lawrence score was determined using standardized preoperative plain radiographs of three views; anteroposterior, lateral and skyline of the patella by a senior radiologist. Intraoperatively, in all cases, photographs of the medial, lateral, and patellofemoral joint compartments were taken. Using the International Cartilage Repair Society (ICRS) score, the degree of chondromalacia was assessed. Subsequently, correlation analysis was performed using the Pearson–Clopper 95% confidence interval (CI). Results There were higher intraoperative scores compared to the preoperative scores in 160 of all cases (63.7% of 251, 95% CI 57.5–69.7%). A mismatch of two score grade points was found in 8.4% (95% CI 5.3–12.5%). The most common mismatch was noted in patients with preoperative Kellgren–Lawrence score of 3 and an intraoperative score of 4 in 48.2% (95% CI 41.9–54.6%). Conclusions The preoperative radiographs using Kellgren–Lawrence underestimate the severity of knee osteoarthritis. The true extent of articular cartilage damage can be better appreciated intraoperatively. In patients undergoing primary TKA, the correlation of clinical symptoms with radiological findings is crucial in deciding when to perform the surgery. Besides, other imaging modalities may be used as an adjunct when the clinical findings and plain radiographs do not correlate.

Arthroscopic bare spot method underestimates true bone defect in bony Bankart lesion Abstract Introduction The need for precise quantification of the glenoid defect should be emphasized in the choice of surgery for bony Bankart lesion especially in its critical values of 16% to 25. The study aims to verify the validity of bare spot method for arthroscopic quantification of glenoid bone defect using several varieties of posterior portal location. Materials and methods Two intact cadaveric glenoids were prepared for the study. The greatest anteroposterior diameter of the perfect circle concept of the glenoid is identified and center of the circle is marked as glenoid bare spot with metal marker. Sixteen percent and 25% defect were sequentially created using a saw at 0° axis parallel to the longitudinal axis of the glenoid. These were confirmed by 3D CT glenoid scan based on glenoid rim distances. Each glenoids were mounted on Sawbone dome holder model simulating neutral version. Quantification of Glenoid bone defects were sequentially measured by glenoid bare spot method arthroscopically by 5 shoulder arthroscopy trained surgeons in 5 varieties of posterior portals in 5 cycles. Paired sample t test was done for arthroscopic over CT scan method of glenoid bone loss quantification. One way ANOVA for portal location analysis was done. Results Glenoid bare spot method significantly underestimates 16% and 25% glenoid bone defect to 9% ± 2 (P < 0.001) and 18% ± 2 (P < 0.001), respectively, compared to 3D CT scan method. There was good intra-class correlation coefficient of 0.97 for inter-rater reliability. There was no significant difference in quantification in between five portal sites by one-way ANOVA (P > 0.05). Conclusions Arthroscopic glenoid bare spot method using the anterior viewing portal significantly underestimates glenoid bone loss in critical margin degrees of decision making in shoulder instability surgery. Minimal variation of posterior portal location for the calibrated probe does not cause significant difference in Glenoid bone loss quantification.

Prospective observation of Clostridium histolyticum collagenase for the treatment of Dupuytren’s disease in 788 patients: the Austrian register Abstract Introduction Since March 2011, the microbial collagenase of Clostridium histolyticum (Xiapex®, Swedish Orphan Biovitrum AB, Stockholm, Sweden) has become available in the European Union for treatment of Dupuytren’s disease. The purpose of this study was to evaluate potential safety risks of Xiapex® and to contribute to a better understanding for its use. Methods A prospective, non-interventional, observational study using Xiapex® for Dupuytren’s disease named XIANIS was conducted between 1.10.2011 and 01.10.2017. Treatment was conducted in accordance to the manufacturer information. Patients were invited for follow-up after 1 week, 1 month, 3 months and 1 year. Demographic data, treatment data, pain levels, anaesthetic application during passive manipulation, subjective function improvement, subjective satisfaction and adverse events were recorded. Results 788 patients with 814 treatments were included who suffered from Dupuytren’s contracture for a mean of 64 months. The metacarpophalangeal joint was affected in 57% of cases and the PIP joint in 40.8% with a mean contracture of 39° and 56°, respectively. A change in the contracture down to 0°–5° was reported in 66.5% of cases, while 25.5% achieved a partial improvement. The pain during the injection was rated 4.5 and 3.3 during passive manipulation. Adverse events were reported in the majority of treated patients with skin tears being one main common event (26%). Further adverse outcomes were bleeding/hematoma, joint swelling, injection-site swelling, pressure sensitivity, erythema, injection-site pain, peripheral edema, blood blisters, blisters, painless lymphadenopathy, painful lymphadenopathy, axillary pain, arthralgia and sensory abnormality. There were no reported tendon ruptures, anaphylactic reactions or ligament injuries. On 1-year follow-up, 29% showed an increased contracture of a mean of 24° with the need for surgical treatment in 2% of patients. 74% of patients were very satisfied and 72% showed a high functional improvement. Conclusion The injectable collagenase Clostridium histolyticum (Xiapex®) proved to be effective and safe in patients with Dupuytren’s disease. Minor adverse events disappeared within 30 days and the need for surgical treatment within 1 year was very low (2%). No major complications or rare side effects were seen in this prospective observational study.

Weight-bearing restrictions reduce postoperative mobility in elderly hip fracture patients Abstract Background and purpose Reduced mobility is a severe threat to the clinical outcomes and survival of elderly hip fracture patients. These patients generally struggle to comply with partial weight bearing, yet postoperative weight-bearing restrictions are still recommended by nearly 25% of surgeons. Therefore, we hypothesized that weight-bearing restrictions in elderly hip fracture patients merely leads to reduced mobility, while transposing full weight to the fractured extremity remains unaffected disregarding the prescribed aftercare. Patients and methods 41 equally treated patients with pertrochanteric fractures were enrolled consecutively in a maximum care hospital in a pre–post study design (level of evidence 2). A study group of 19 patients was instructed to maintain partial weight bearing (PWB), whereas the control group of 22 patients was instructed to mobilize at full weight bearing (FWB). All patients were asked to participate in a gait analysis using an insole force sensor (loadsol®, Novel, Munich, Germany) on the fifth postoperative day. Results The postoperative Parker Mobility Score in the PWB group compared to the FWB group was significantly reduced (3.21 vs. 4.73, p < 0.001). Accordingly, a significantly lower gait speed in the PWB group of 0.16 m/s vs. 0.28 m/s was seen (p = 0.003). No difference in weight bearing was observed in between the groups (average peak force 350.25 N vs. 353.08 N, p = 0.918), nor any differences in the demographic characteristics, ASA Score, Barthel Index or EQ5D. Interpretation Weight-bearing restrictions in elderly hip fracture patients contributed to a loss of mobility, while no significant differences in loading of the affected extremity were observed. Therefore, postoperative weight-bearing restrictions in elderly hip fracture patients should be avoided, to achieve early mobilization at full weight bearing.

Fifty top-cited classic papers in orthopaedic oncology: a bibliometric analysis Abstract Introduction Citation analysis has been used to evaluate the impact of papers in medicine. There has been multitude of orthopaedic oncology-related papers in literature, to our knowledge no citation analysis of orthopaedic oncology papers has been performed. We identified the 50 most-cited orthopaedic oncology papers and evaluated these papers in terms of their time of publication, source journals, countries, institutions, authors, and main topics. Materials and methods Science citation index expanded was searched in April 2018 for citations of papers published in 77 selected journals since the beginning of the database. The 50 most-cited orthopaedic oncology papers were identified and evaluated. Results The number of citations for the top 50 papers ranged from 168 to 1162 (mean 308). These papers were published between 1957 and 2010. 1990s was the most productive decade, with 19 papers of the list. All papers were written in English and they were published in a total of 6 journals. The Journal of Bone and Joint Surgery-Am published the largest number of papers with 31, followed by Clinical Orthopaedics and Related Research with 8. The top 50 papers were created mainly from US and Japan, respectively, with 33 and 5. Conclusions It is difficult to define the exact impact of a single paper in the literature. In doing citation analysis, it provides us perspective in the history and progress of orthopaedic oncology.

Occurrence of never events after total joint arthroplasty in the United States Abstract Background Total joint arthroplasty (TJA) is a major orthopedic procedure associated with substantial morbidity and mortality. Never events (NEs) are harmful hospital-acquired conditions (HACs) that are preventable. Methods Information on hospital admissions with TJA was collected from the National Inpatient Sample (NIS) from 2003 to 2012. NIS was queried to identify NE applicable to TJA patients based on the HAC definition listed by the Centers for Medicare and Medicaid Services (CMS). NEs were further compared before and after 2008 to evaluate the effect of the new CMS non-reimbursement policy on their incidence. Results A total of 8,176,774 patients were admitted with TJA from 2003 to 2012. 108,668 patients of these (1.33%) had ≥ 1 NE. The most prevalent NE was fall and trauma (0.7%). Significant multivariable predictors with higher odds of developing at least one NE included weekend admission [odds ratio (99.9% CI), 4.3 (3.1, 5.8), p < 0.001] and weight loss [odds ratio (99.9% CI), 2.8 (2.2, 3.5), p < 0.001]. A temporal comparison of NE before and after 2008 revealed a decrease in total NE occurrence after 2008 when the CMS announced discontinuing payment for NE (1.39% vs. 1.25%, p < 0.001). After adjustment for potential confounding risk factors, NE after TJA was significantly associated with an increased mortality (p < 0.001), a longer hospital stay (p < 0.001), and higher total hospitalization charges (p < 0.001). Conclusions These data demonstrated that NE in TJA patients was predictive of an increased mortality, length of hospital stay, and hospitalization costs. This study established baseline NE rates in the TJA patient population to use as benchmarks and identified target areas for quality improvement in US.

Risk factors of hyperextension and its relationship with the clinical outcomes following mobile-bearing total knee arthroplasty Abstract Introduction To evaluate the incidence and risk factors of postoperative hyperextension after mobile-bearing total knee arthroplasty (TKA) and its clinical outcomes. Materials and methods This retrospective case–control study included 387 knees of primary TKA patients after a 5-year follow-up. The clinical outcomes and radiographs including posterior condylar offset (PCO), femur and tibial slope angle and its discrepancy were evaluated. The patients were divided into two groups (group 1: non-hyperextension, group 2: hyperextension). An extension greater than 5° measured using a goniometer at the final follow-up was defined as hyperextension. Logistic and linear regression analyses were performed. Results Overall, 43 knees (11.1%) with hyperextension were observed at the last follow-up. There was no significant difference between groups in terms of the clinical outcomes although the functional scores were worse in group 2. There was no significant difference in the postoperative radiologic evaluation except for a change in PCO (group 1 vs. group 2; − 0.2 mm ± 3.8 vs. − 2.4 mm ± 3.0, p = 0.003), distal femoral resection slope angle (− 9.1° ± 2.1 vs. − 12.1° ± 1.7, p < 0.000) and discrepancy of the slope angle (0.3° ± 4.5 vs. − 3.6° ± 3.9, p < 0.000). The change in PCO [odds ratio (OR) 0.86, p = 0.012], discrepancy of the slope angle (OR 0.8136, p = 0.000) and the preoperative mechanical femorotibial angle (OR 1.09, p = 0.003) were associated with hyperextension. Conclusion Mobile-bearing TKA with hyperextension over 5° showed worse functional outcomes at the mid-term follow-up, even though no serious complications were observed. Care should be taken to maintain the posterior condylar offset and to match the resection angles in femur and tibia due to the risk of hyperextension and worse functional outcomes. Level of evidence IV.