Aims. Cauda equina syndrome (CES) can be associated with chronic severe lower back pain and long-term autonomic dysfunction. This study assesses the recently defined core outcome set for CES in a cohort of patients using validated questionnaires. Methods. Between January 2005 and December 2019, 82 patients underwent surgical decompression for acute CES secondary to massive lumbar disc prolapse at our hospital. After review of their records, patients were included if they presented with the clinical and radiological features of CES, then classified as CES incomplete (CESI) or with painless urinary retention (CESR) in accordance with guidelines published by the British Association of Spinal Surgeons. Patients provided written consent and completed a series of questionnaires. Results. In total, 61 of 82 patients returned a completed survey. Their mean age at presentation was 43 years (20 to 77; SD 12.7), and the mean duration of follow-up 58.2 months (11 to 182; SD 45.3). Autonomic dysfunction was frequent: 33% of patients reported bladder dysfunction, and 10% required a urinary catheter. There was a 38% and 53% incidence of bowel and sexual dysfunction, respectively: 47% of patients reported genital numbness. A total of 67% reported significant back pain: 44% required further investigation and 10% further intervention for the management of lower back pain. Quality of life was lower than expected when corrected for age and sex. Half the patients reported moderate or worse depression, and 40% of patients of working age could no longer work due to problems attributable to CES. Urinary and faecal incontinence, catheter use, sexual dysfunction, and genital numbness were significantly more common in patients with CESR. Conclusion. This study reports the long-term outcome of patients with CES and is the first to use validated patient-reported outcome measures to assess the CES Core Outcome Set. Persistent severe back pain and on-going autonomic dysfunction were frequently reported at a mean follow-up of five years. Cite this article: Bone Joint J 2021;103-B(9):1464–1471

Aims. Tenosynovial giant cell tumour (TGCT) is one of the most common soft-tissue tumours of the foot and ankle and can behave in a locally aggressive manner. Tumour control can be difficult, despite the various methods of treatment available. Since treatment guidelines are lacking, the aim of this study was to review the multidisciplinary management by presenting the largest series of TGCT of the foot and ankle to date from two specialized sarcoma centres. Methods. The Oxford Tumour Registry and the Leiden University Medical Centre Sarcoma Registry were retrospectively reviewed for patients with histologically proven foot and ankle TGCT diagnosed between January 2002 and August 2019. Results. A total of 84 patients were included. There were 39 men and 45 women with a mean age at primary treatment of 38.3 years (9 to 72). The median follow-up was 46.5 months (interquartile range (IQR) 21.3 to 82.3). Localized-type TGCT (n = 15) predominantly affected forefoot, whereas diffuse-type TGCT (Dt-TGCT) (n = 9) tended to panarticular involvement. TGCT was not included in the radiological differential diagnosis in 20% (n = 15/75). Most patients had open rather than arthroscopic surgery (76 vs 17). The highest recurrence rates were seen with Dt-TGCT (61%; n = 23/38), panarticular involvement (83%; n = 5/8), and after arthroscopy (47%; n = 8/17). Three (4%) fusions were carried out for osteochondral destruction by Dt-TGCT. There were 14 (16%) patients with Dt-TGCT who underwent systemic treatment, mostly in refractory cases (79%; n = 11). TGCT initially decreased or stabilized in 12 patients (86%), but progressed in five (36%) during follow-up; all five underwent subsequent surgery. Side effects were reported in 12 patients (86%). Conclusion. We recommend open surgical excision as the primary treatment for TGCT of the foot and ankle, particularly in patients with Dt-TGCT with extra-articular involvement. Severe osteochondral destruction may justify salvage procedures, although these are not often undertaken. Systemic treatment is indicated for unresectable or refractory cases. However, side effects are commonly experienced, and relapses may occur once treatment has ceased. Cite this article: Bone Joint J 2021;103-B(4):788–794

Aims. We aimed to compare the implant survival, complications, readmissions, and mortality of Vancouver B2 periprosthetic femoral fractures (PFFs) treated with internal fixation with that of B1 PFFs treated with internal fixation and B2 fractures treated with revision arthroplasty. Methods. We retrospectively reviewed the data of 112 PFFs, of which 47 (42%) B1 and 27 (24%) B2 PFFs were treated with internal fixation, whereas 38 (34%) B2 fractures underwent revision arthroplasty. Decision to perform internal fixation for B2 PFFs was based on specific radiological (polished femoral components, intact bone-cement interface) and clinical criteria (low-demand patient). Median follow-up was 36.4 months (24 to 60). Implant survival and mortality over time were estimated with the Kaplan-Meier method. Adverse events (measured with a modified Dindo-Clavien classification) and 90-day readmissions were additionally compared between groups. Results. In all, nine (8.01%) surgical failures were detected. All failures occurred within the first 24 months following surgery. The 24-month implant survival was 95.4% (95% confidence interval (CI) 89.13 to 100) for B1 fractures treated with internal fixation, 90% (95% CI 76.86 to 100) for B2 PFFs treated with osteosynthesis-only, and 85.8% (95% CI 74.24 to 97.36) for B2 fractures treated with revision THA, without significant differences between groups (p = 0.296). Readmissions and major adverse events including mortality were overall high, but similar between groups (p > 0.05). The two-year patient survival rate was 87.1% (95% CI 77.49 to 95.76), 66.7% (95% CI 48.86 to 84.53), and 84.2% (95% CI 72.63 to 95.76), for the B1 group, B2 osteosynthesis group, and B2 revision group, respectively (p = 0.102). Conclusion. Implant survival in Vancouver B2 PFFs treated with internal fixation was similar to that of B1 fractures treated with the same method and to B2 PFFs treated with revision arthroplasty. Low-demand, elderly patients with B2 fractures around well-cemented polished femoral components with an intact bone-cement interface can be safely treated with internal fixation. Cite this article: Bone Joint J 2021;103-B(7):1222–1230

Aims. The objective of this systematic review was to describe trapeziectomy outcomes and complications in the context of osteoarthritis of the base of the thumb after a five-year minimum follow-up. Methods. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to guide study design, and 267 full-text articles were assessed for eligibility. After exclusion criteria application, 22 studies were included, involving 728 patients and 823 trapeziectomies. Outcomes included pre- and postoperative clinical and radiological characteristics. Complications and revisions were recorded. Results. All the studies reported good results regarding pain and range of motion at the last follow-up of 8.3 years (5 to 22); the mean satisfaction rate was 91% (84% to 100%). It was difficult to assess the impact on metacarpophalangeal joint motion in extension with contrary results. The key pinch returned to its preoperative values, whereas tip pinch showed a modest improvement (+14%), with a mild improvement found in grip strength (+25%) at the last follow-up. The mean progressive trapezial collapse was 48% (0% to 85%) and was not correlated with pain, grip strength, or satisfaction. The most represented complications were linked to tendons or nerves affected during additional procedures to stabilize the joint (11.6%; n = 56). Mechanical complications included symptomatic scapho-M1 impingement (3.1%; n = 15/580), leading to nine surgical revisions out of 581 trapeziectomies. Meta-analysis was not possible due to study heterogeneity and limited data. Conclusion. After a minimum five-year follow-up, trapeziectomy achieved high patient satisfaction and pain relief. However, strength seemed to be deteriorating with detrimental consequences, but this did not correlate with trapezial collapse. The issues related to underestimating mechanical complications and varying degrees of success should be highlighted in the information given to patients. Evidence-based analyses should help the surgeon in their decision-making. Cite this article: Bone Jt Open 2021;2(3):141–149

Aims. The objective of this study was to evaluate the clinical and radiological outcomes of patients younger than six months of age with developmental dysplasia of the hip (DDH) managed by either a Pavlik harness or Tübingen hip flexion splint. Methods. Records of 251 consecutive infants with a mean age of 89 days (SD 47), diagnosed with DDH between January 2015 and December 2018, were retrospectively reviewed. Inclusion criteria for patients with DDH were: younger than 180 days at the time of diagnosis; ultrasound Graf classification of IIc or greater; treatment by Pavlik harness or Tübingen splint; and no prior treatment history. All patients underwent hip ultrasound every seven days during the first three weeks of treatment and subsequently every three to four weeks until completion of treatment. If no signs of improvement were found after three weeks, the Pavlik harness or Tübingen splint was discontinued. Statistical analysis was performed. Results. The study included 251 patients with Graf grades IIc to IV in 18 males and 233 females with DDH. Mean follow-up time was 22 months (SD 10). A total of 116 hips were graded as Graf IIc (39.1%), nine as grade D (3.0%), 100 as grade III (33.7%), and 72 as grade IV (24.2%). There were 109 patients (128 hips) in the Pavlik group and 142 patients (169 hips) in the Tübingen group (p = 0.227). The Tübingen group showed a 69.8% success rate in Graf III and Graf IV hips while the success rate was significantly lower in the Pavlik group, 53.9% (p = 0.033). For infants older than three months of age, the Tübingen group showed a 71.4% success rate, and the Pavlik group a 54.4% success rate (p = 0.047). Conclusion. The Tübingen splint should be the preferred treatment option for children older than three months, and for those with severe forms of DDH such as Graf grade III and IV, who are younger than six months at time of diagnosis. The Tübingen hip flexion splint is a valid alternative to the Pavlik harness for older infants and those with more severe DDH. Cite this article: Bone Joint J 2021;103-B(5):991–998

Aims. Several radiological methods of measuring anteversion of the acetabular component after total hip arthroplasty (THA) have been described. These are limited by low reproducibility, are less accurate than CT 3D reconstruction, and are cumbersome to use. These methods also partly rely on the identification of obscured radiological borders of the component. We propose two novel methods, the Area and Orthogonal methods, which have been designed to maximize use of readily identifiable points while maintaining the same trigonometric principles. Patients and Methods. A retrospective study of plain radiographs was conducted on 160 hips of 141 patients who had undergone primary THA. We compared the reliability and accuracy of the Area and Orthogonal methods with two of the current leading methods: those of Widmer and Lewinnek, respectively. Results. The 160 anteroposterior pelvis films revealed that the proposed Area method was statistically different from those described by Widmer and Lewinnek (p < 0.001 and p = 0.004, respectively). They gave the highest inter- and intraobserver reliability (0.992 and 0.998, respectively), and took less time (27.50 seconds (. sd. 3.19); p < 0.001) to complete. In addition, 21 available CT 3D reconstructions revealed the Area method achieved the highest Pearson’s correlation coefficient (r = 0.956; p < 0.001) and least statistical difference (p = 0.704) from CT with a mean within 1° of CT-3D reconstruction between ranges of 1° to 30° of measured radiological anteversion. Conclusion. Our results support the proposed Area method to be the most reliable, accurate, and speedy. They did not support any statistical superiority of the proposed Orthogonal method to that of the Widmer or Lewinnek method. Cite this article: Bone Joint J 2019;101-B:1042–1049

Aims. The aim of this study was to determine the differences in spinal imaging characteristics between subjects with or without lumbar developmental spinal stenosis (DSS) in a population-based cohort. Methods. This was a radiological analysis of 2,387 participants who underwent L1-S1 MRI. Means and ranges were calculated for age, sex, BMI, and MRI measurements. Anteroposterior (AP) vertebral canal diameters were used to differentiate those with DSS from controls. Other imaging parameters included vertebral body dimensions, spinal canal dimensions, disc degeneration scores, and facet joint orientation. Mann-Whitney U and chi-squared tests were conducted to search for measurement differences between those with DSS and controls. In order to identify possible associations between DSS and MRI parameters, those who were statistically significant in the univariate binary logistic regression were included in a multivariate stepwise logistic regression after adjusting for demographics. Odds ratios (ORs) and 95% confidence intervals (CIs) were reported where appropriate. Results. Axial AP vertebral canal diameter (p < 0.001), interpedicular distance (p < 0.001), AP dural sac diameter (p < 0.001), lamina angle (p < 0.001), and sagittal mid-vertebral body height (p < 0.001) were significantly different between those identified as having DSS and controls. Narrower interpedicular distance (OR 0.745 (95% CI 0.618 to 0.900); p = 0.002) and AP dural sac diameter (OR 0.506 (95% CI 0.400 to 0.641); p < 0.001) were associated with DSS. Lamina angle (OR 1.127 (95% CI 1.045 to 1.214); p = 0.002) and right facet joint angulation (OR 0.022 (95% CI 0.002 to 0.247); p = 0.002) were also associated with DSS. No association was observed between disc parameters and DSS. Conclusion. From this large-scale cohort, the canal size is found to be independent of body stature. Other than spinal canal dimensions, abnormal orientations of lamina angle and facet joint angulation may also be a result of developmental variations, leading to increased likelihood of DSS. Other skeletal parameters are spared. There was no relationship between DSS and soft tissue changes of the spinal column, which suggests that DSS is a unique result of bony maldevelopment. These findings require validation in other ethnicities and populations. Level of Evidence: I (diagnostic study). Cite this article: Bone Joint J 2021;103-B(4):725–733

Aims. Debate continues regarding the optimum management of periprosthetic distal femoral fractures (PDFFs). This study aims to determine which operative treatment is associated with the lowest perioperative morbidity and mortality when treating low (Su type II and III) PDFFs comparing lateral locking plate fixation (LLP-ORIF) or distal femoral arthroplasty (DFA). Methods. This was a retrospective cohort study of 60 consecutive unilateral (PDFFs) of Su types II (40/60) and III (20/60) in patients aged ≥ 60 years: 33 underwent LLP-ORIF (mean age 81.3 years (SD 10.5), BMI 26.7 (SD 5.5); 29/33 female); and 27 underwent DFA (mean age 78.8 years (SD 8.3); BMI 26.7 (SD 6.6); 19/27 female). The primary outcome measure was reoperation. Secondary outcomes included perioperative complications, calculated blood loss, transfusion requirements, functional mobility status, length of acute hospital stay, discharge destination and mortality. Kaplan-Meier survival analysis was performed. Cox multivariate regression analysis was performed to identify risk factors for reoperation after LLP-ORIF. Results. Follow-up was at mean 3.8 years (1.0 to 10.4). One-year mortality was 13% (8/60). Reoperation was more common following LLP-ORIF: 7/33 versus 0/27 (p = 0.008). Five-year survival for reoperation was significantly better following DFA; 100% compared to 70.8% (95% confidence interval (CI) 51.8% to 89.8%, p = 0.006). There was no difference for the endpoint mechanical failure (including radiological loosening); ORIF 74.5% (56.3 to 92.7), and DFA 78.2% (52.3 to 100, p = 0.182). Reoperation following LLP-ORIF was independently associated with medial comminution; hazard ratio (HR) 10.7 (1.45 to 79.5, p = 0.020). Anatomical reduction was protective against reoperation; HR 0.11 (0.013 to 0.96, p = 0.046). When inadequately fixed fractures were excluded, there was no difference in five-year survival for either reoperation (p = 0.156) or mechanical failure (p = 0.453). Conclusion. Absolute reoperation rates are higher following LLP fixation of low PDFFs compared to DFA. Where LLP-ORIF was well performed with augmentation of medial comminution, there was no difference in survival compared to DFA. Though necessary in very low fractures, DFA should be used with caution in patients with greater life expectancies due to the risk of longer term aseptic loosening. Cite this article: Bone Joint J 2021;103-B(4):635–643

Aims. To compare the functionality of adults with displaced mid-shaft clavicular fractures treated either operatively or nonoperatively and to compare the relative risk of nonunion and reoperation between the two groups. Methods. Based on specific eligibility criteria, 120 adults (median age 37.5 years (interquartile range (18 to 61)) and 84% males (n = 101)) diagnosed with an acute displaced mid-shaft fracture were recruited, and randomized to either the operative (n = 60) or nonoperative (n = 60) treatment group. This randomized controlled, partially blinded trial followed patients for 12 months following initial treatment. Functionality was assessed by the Constant score (CS) (assessor blinded to treatment) and Disability of the Arm, Shoulder and Hand (DASH) score. Clinical and radiological evaluation, and review of patient files for complications and reoperations, were added as secondary outcomes. Results. At 12 months, 87.5% of patients (n = 105) were available for analysis. The two groups were well balanced based on demographic and fracture-related characteristics. At six weeks of follow-up a significant difference in DASH score (p < 0.001) was found in favour of operative treatment. The functionality at 12 months of follow-up based on CS and DASH was excellent in both groups (CS > 90 points and DASH < 10 points) with no significant difference (p = 0.277 for DASH and p = 0.184 for CS) between the two groups. The risk of symptomatic nonunion was significantly higher in the nonoperative group (p = 0.014), with a relative risk of 9.47 (95% confidence interval (CI) 1.26 to 71.53) in this group compared to the operative group. The number-needed-to-treat to avoid one symptomatic nonunion was 6.2. Initial treatment and age were factors significantly associated with nonunion in a logistic analysis. There were 26% in both groups (n = 14 in operative group and n = 15 in nonoperative group) who required secondary surgery, with most indications in the nonoperative group mandatory due to nonunion compared to most relative indications in the operative group requiring intervention due to implant irritation. Conclusion. Superiority was not identified with either an all-operative or all-nonoperative approach. The functionality at short term (within six weeks) seems igreater following operative treatment but was not found at one year. The risk of nonunion is significantly higher with nonoperative treatment. However, an all-operative approach to lower the nonunion risk may result in unnecessary surgery and is not recommended. Cite this article: Bone Joint J 2021;103-B(4):762–768

Aims. The aim of this study was to investigate whether clinical and radiological outcomes after intramedullary nailing of displaced fractures of the fifth metacarpal neck using a single thick Kirschner wire (K-wire) are noninferior to those of technically more demanding fixation with two thinner dual wires. Patients and Methods. This was a multicentre, parallel group, randomized controlled noninferiority trial conducted at 12 tertiary trauma centres in Germany. A total of 290 patients with acute displaced fractures of the fifth metacarpal neck were randomized to either intramedullary single-wire (n = 146) or dual-wire fixation (n = 144). The primary outcome was the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire six months after surgery, with a third of the minimal clinically important difference (MCID) used as the noninferiority threshold. Secondary outcomes were pain, health-related quality of life (EuroQol five-dimensional questionnaire (EQ-5D)), radiological measures, functional deficits, and complications. Results. Overall, 151/290 of patients (52%) completed the six months of follow-up, leaving 83 patients in the single-wire group and 68 patients in the dual-wire group. In the modified intention-to-treat analysis set, mean DASH scores six months after surgery were 3.8 (. sd. 7.0) and 4.4 (. sd. 9.4), respectively. With multiple imputation (n = 288), mean DASH scores were estimated at 6.3 (. sd. 8.7) and 7.0 (. sd. 10.0). Upper (1 - 2α)) confidence limits consistently remained below the noninferiority margin of 3.0 points in the DASH instrument. While there was a statistically nonsignificant trend towards a higher rate of shortening and rotational malalignment in the single wire group, no statistically significant differences were observed across groups in any secondary outcome measure. Conclusion. A single thick K-wire is sufficient for intramedullary fixation of acute displaced subcapital fractures of the fifth metacarpal neck. The less technically demanding single-wire technique produces noninferior clinical and radiological outcomes compared with the dual-wire approach. Cite this article: Bone Joint J 2019;101-B:1263–1271

Aims. Periprosthetic joint infections (PJIs) and osteomyelitis are clinical challenges that are difficult to eradicate. Well-characterized large animal models necessary for testing and validating new treatment strategies for these conditions are lacking. The purpose of this study was to develop a rabbit model of chronic PJI in the distal femur. Methods. Fresh suspensions of Staphylococcus aureus (ATCC 25923) were prepared in phosphate-buffered saline (PBS) (1 × 10. 9. colony-forming units (CFUs)/ml). Periprosthetic osteomyelitis in female New Zealand white rabbits was induced by intraosseous injection of planktonic bacterial suspension into a predrilled bone tunnel prior to implant screw placement, examined at five and 28 days (n = 5/group) after surgery, and compared to a control aseptic screw group. Radiographs were obtained weekly, and blood was collected to measure ESR, CRP, and white blood cell (WBC) counts. Bone samples and implanted screws were harvested on day 28, and processed for histological analysis and viability assay of bacteria, respectively. Results. Intraosseous periprosthetic introduction of planktonic bacteria induced an acute rise in ESR and CRP that subsided by day 14, and resulted in radiologically evident periprosthetic osteolysis by day 28 accompanied by elevated WBC counts and histological evidence of bacteria in the bone tunnels after screw removal. The aseptic screw group induced no increase in ESR, and no lysis developed around the implants. Bacterial viability was confirmed by implant sonication fluid culture. Conclusion. Intraosseous periprosthetic introduction of planktonic bacteria reliably induces survivable chronic PJI in rabbits. Cite this article: Bone Joint Res 2021;10(3):156–165

Aims. Arthroplasty for end-stage hallux rigidus (HR) is controversial. Arthrodesis remains the gold standard for surgical treatment, although is not without its complications, with rates of up to 10% for nonunion, 14% for reoperation and 10% for metatarsalgia. The aim of this study was to analyze the outcome of a double-stemmed silastic implant (Wright-Medical, Memphis, Tennessee, USA) for patients with end-stage HR. Methods. We conducted a retrospective review of 108 consecutive implants in 76 patients, between January 2005 and December 2016, with a minimum follow-up of two years. The mean age of the patients at the time of surgery was 61.6 years (42 to 84). There were 104 females and four males. Clinical, radiological, patient reported outcome measures (PROMS) data, a visual analogue score (VAS) for pain, and satisfaction scores were collected. Results. The survivorship at a mean follow-up of 5.3 years (2.1 to 14.1) was 97.2%. The mean Manchester Oxford Foot and Ankle Questionnaire (MOXFQ) scores improved from 78.1 to 11.0, and VAS scores for pain from 7/10 to 1.3/10. The rate of satisfaction was 90.6%. Three implants (2.8%) required revision; one for infection, one-month postoperatively, and two for stem breakage at 10.4 and 13.3 years postoperatively. There was a 1.9% reoperation rate other than revision, 23.1% of patients developed a minor complication, and 21.1% of patients had non-progressive and asymptomatic cysts on radiological review. Conclusion. We report a 97.2% survivorship at a mean follow-up of 5.3 years with this implant. We did not find progressive osteolysis, as has been previously reported. These results suggest that this double-stemmed silastic implant provides a predictable and reliable alternative with comparable outcomes to arthrodesis for the treatment of end-stage HR. Cite this article: Bone Joint J 2020;102-B(2):220–226

Aims. In a randomized controlled trial with two-year follow-up, patients treated with suture button (SB) for acute syndesmotic injury had better outcomes than patients treated with syndesmotic screw (SS). The aim of this study was to compare clinical and radiological outcomes for these treatment groups after five years. Methods. A total of 97 patients with acute syndesmotic injury were randomized to SS or SB. The five-year follow-up rate was 81 patients (84%). The primary outcome was the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle Hindfoot Scale. Secondary outcome measures included Olerud-Molander Ankle (OMA) score, visual analogue scale (VAS), EuroQol five-dimension questionnaire (EQ-5D), range of movement, complications, reoperations, and radiological results. CT scans of both ankles were obtained after surgery, and after one, two, and five years. Results. The SB group had higher median AOFAS score (100 (interquartile range (IQR) 92 to 100) vs 90 (IQR 85 to 100); p = 0.006) and higher median OMA score (100 (IQR 95 to 100) vs 95 (IQR 75 to 100); p = 0.006). The SS group had a higher incidence of ankle osteoarthritis (OA) (24 (65%) vs 14 (35%), odds ratio (OR) 3.4 (95% confidence interval (CI) 1.3 to 8.8); p = 0.009). On axial CT we measured a significantly smaller mean difference in the anterior tibiofibular distance between injured and non-injured ankles in the SB group (–0.1 mm vs 1.2 mm; p = 0.016). Conclusion. Five years after syndesmotic injury treated with either SB or SS, we found better AOFAS and OMA scores, and lower incidence of ankle OA, in the SB group. These long-term results favour the use of SB when treating an acute syndesmotic injury. Cite this article: Bone Joint J 2020;102-B(2):212–219

Aims. A comprehensive classification for coronal lower limb alignment with predictive capabilities for knee balance would be beneficial in total knee arthroplasty (TKA). This paper describes the Coronal Plane Alignment of the Knee (CPAK) classification and examines its utility in preoperative soft tissue balance prediction, comparing kinematic alignment (KA) to mechanical alignment (MA). Methods. A radiological analysis of 500 healthy and 500 osteoarthritic (OA) knees was used to assess the applicability of the CPAK classification. CPAK comprises nine phenotypes based on the arithmetic HKA (aHKA) that estimates constitutional limb alignment and joint line obliquity (JLO). Intraoperative balance was compared within each phenotype in a cohort of 138 computer-assisted TKAs randomized to KA or MA. Primary outcomes included descriptive analyses of healthy and OA groups per CPAK type, and comparison of balance at 10° of flexion within each type. Secondary outcomes assessed balance at 45° and 90° and bone recuts required to achieve final knee balance within each CPAK type. Results. There was similar frequency distribution between healthy and arthritic groups across all CPAK types. The most common categories were Type II (39.2% healthy vs 32.2% OA), Type I (26.4% healthy vs 19.4% OA) and Type V (15.4% healthy vs 14.6% OA). CPAK Types VII, VIII, and IX were rare in both populations. Across all CPAK types, a greater proportion of KA TKAs achieved optimal balance compared to MA. This effect was largest, and statistically significant, in CPAK Types I (100% KA vs 15% MA; p < 0.001), Type II (78% KA vs 46% MA; p = 0.018). and Type IV (89% KA vs 0% MA; p < 0.001). Conclusion. CPAK is a pragmatic, comprehensive classification for coronal knee alignment, based on constitutional alignment and JLO, that can be used in healthy and arthritic knees. CPAK identifies which knee phenotypes may benefit most from KA when optimization of soft tissue balance is prioritized. Further, it will allow for consistency of reporting in future studies. Cite this article: Bone Joint J 2021;103-B(2):329–337

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The outcomes following nonoperative management of minimally displaced greater tuberosity (GT) fractures, and the factors which influence patient experience, remain poorly defined. We assessed the early patient-derived outcomes following these injuries and examined the effect of a range of demographic- and injury-related variables on these outcomes.

Aims. The aim of this study was to analyze the complications and outcomes of treatment in a series of previously untreated patients with a primary aneurysmal bone cyst (ABC) who had been treated by percutaneous sclerosant therapy using polidocanol. Methods. Between January 2010 and December 2016, 56 patients were treated primarily with serial intralesional sclerosant injections. Their mean age was 20 years (1 to 54). The sites involved were clavicle (n = 3), humeri (n = 11), radius (n = 1), ulna (n = 3), hand (n = 2), pelvis (n = 12), femur (n = 7), tibia (n = 13), fibula (n = 3), and foot (n = 1). After histopathological confirmation of the diagnosis, 3% polidocanol (hydroxypolyaethoxydodecan) was injected into the lesion under image intensifier guidance. Patients were evaluated clinically and radiologically every six to eight weeks. In the absence of clinical and/or radiological response, a repeat sclerosant injection was given after eight to 12 weeks and repeated at similar intervals if necessary. Results. There were no complications of treatment. One patient was lost to follow-up. Overall, 46/55 (84%) of lesions healed after one or more injections of polidocanol: 24/55 (44%) patients healed with a single injection, and 43/55 (78%) within two injections. Of these 46, four (9%) patients developed local recurrence, two of whom healed with a repeat sclerosant injection. Thus, 44/55 (80%) patients of primary ABC healed with sclerotherapy. The mean follow-up was 62 months (20 to 111). The local recurrence free survival (LRFS) with percutaneous sclerosant therapy with polidocanol was 100%, 98% (95% confidence interval (CI) 85 to 100) and 93% (95% CI 78 to 98) at two, three, and five years, respectively. Conclusion. Percutaneous sclerotherapy using polidocanol is a safe, effective, minimally invasive and inexpensive method of treating a primary ABC of the limbs or pelvis. Cite this article: Bone Joint J 2020;102-B(2):186–190

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Radiological residual acetabular dysplasia (RAD) has been reported in up to 30% of children who had successful brace treatment of infant developmental dysplasia of the hip (DDH). Predicting those who will resolve and those who may need corrective surgery is important to optimize follow-up protocols. In this study we have aimed to identify the prevalence and predictors of RAD at two years and five years post-bracing.

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To identify the incidence and risk factors for five-year same-site recurrent disc herniation (sRDH) after primary single-level lumbar discectomy. Secondary outcome was the incidence and risk factors for five-year sRDH reoperation.

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Due to its indolent clinical behaviour, the treatment paradigm of atypical cartilaginous tumours (ACTs) in the long bones is slowly shifting from intralesional resection (curettage) and local adjuvants, towards active surveillance through wait-and-scan follow-up. In this retrospective cohort study performed in a tertiary referral centre, we studied the natural behaviour of ACT lesions by active surveillance with MRI. Clinical symptoms were not considered in the surveillance programme.