Antegrade nailing of proximal humeral fractures using a straight nail can damage the bony insertion of the supraspinatus tendon and may lead to varus failure of the construct. In order to establish the ideal anatomical landmarks for insertion of the nail and their clinical relevance we analysed CT scans of bilateral proximal humeri in 200 patients (mean age 45.1 years (sd 19.6; 18 to 97) without humeral fractures. The entry point of the nail was defined by the point of intersection of the anteroposterior and lateral vertical axes with the cortex of the humeral head. The critical point was defined as the intersection of the sagittal axis with the medial limit of the insertion of the supraspinatus tendon on the greater tuberosity. The region of interest, i.e. the biggest entry hole that would not encroach on the insertion of the supraspinatus tendon, was calculated setting a 3 mm minimal distance from the critical point. This identified that 38.5% of the humeral heads were categorised as ‘critical types’, due to morphology in which the predicted offset of the entry point would encroach on the insertion of the supraspinatus tendon that may damage the tendon and reduce the stability of fixation.

We therefore emphasise the need for ‘fastidious’ pre-operative planning to minimise this risk.

Cite this article: Bone Joint J 2014;96-B:249–53.

Polyethylene particulate wear debris continues to be implicated in the aetiology of aseptic loosening following knee arthroplasty. The Oxford unicompartmental knee arthroplasty employs a spherical femoral component and a fully congruous meniscal bearing to increase contact area and theoretically reduce the potential for polyethylene wear. This study measures the in vivo ten-year linear wear of the device, using a roentgenstereophotogrammetric technique.

In this in vivo study, seven medial Oxford unicompartmental prostheses, which had been implanted ten years previously were studied. Stereo pairs of radiographs were acquired for each patient and the films were analysed using a roentgen stereophotogrammetric analysis calibration and a computer-aided design model silhouette-fitting technique. Penetration of the femoral component into the original volume of the bearing was our estimate of linear wear. In addition, eight control patients were examined less than three weeks post-insertion of an Oxford prosthesis, where no wear would be expected. The control group showed no measured wear and suggested a system accuracy of 0.1 mm. At ten years, the mean linear wear rate was 0.02 mm/year.

The results from this in vivo study confirm that the device has low ten-year linear wear in clinical practice. This may offer the device a survival advantage in the long term.

Excision of a physeal bar and filling the space with interposition material may allow resumption of normal growth. Both the extent and the location of the bar and the amount of growth remaining from physis must be determined. Computer-assisted surgery is being used increasingly in various fields of orthopaedics. We describe the management of a patient with premature physeal arrest of the right distal tibia in which resection of a physeal bar was achieved under real-time three-dimensional intra-operative monitoring by computer-assisted navigation.

The advantage of this method over other means of imaging is that intra-operative identification can increase the accuracy of resection of the bar.

The August 2013 Shoulder & Elbow Roundup³⁶⁰ looks at: the sternoclavicular joint revisited; surgical simulators: more than just a fancy idea?; arthroscopic tennis elbow release; costly clavicle stabilisation; a better treatment for tennis elbow?; shock news: surgeons and radiologists agree; overhead athletes and SLAP repair; and total shoulder arthroplasty more effective than hemiarthroplasty

We investigated the three-dimensional morphological differences of the articular surface of the femoral trochlea in patients with recurrent dislocation of the patella and a normal control group using three-dimensional computer models.

There were 12 patients (12 knees) and ten control subjects (ten knees). Three-dimensional computer models of the femur, including the articular cartilage, were created. Evaluation was performed on the shape of the articular surface, focused on its convexity, and the proximal and mediolateral distribution of the articular cartilage of the femoral trochlea. The extent of any convexity, and the proximal distribution of the articular cartilage, expressed as the height, were shown by the angles about the transepicondylar axis. The mediolateral distribution of the articular cartilage was assessed by the location of the medial and lateral borders of the articular cartilage.

The mean extent of convexity was 24.9° sd 6.7° for patients and 11.9° sd 3.6° for the control group (p < 0.001). The mean height of the articular cartilage was 91.3° sd 8.3° for the patients and 83.3° sd 7.7° for the control group (p = 0.03), suggesting a wider convex trochlea in the patients with recurrent dislocation of the patella caused by the proximally-extended convex area. The lateral border of the articular cartilage of the trochlea in the patients was more laterally located than in the control group.

Our findings therefore quantitatively demonstrated differences in the shape and distribution of the articular cartilage on the femoral trochlea between patients with dislocation of the patella and normal subjects.

The April 2013 Shoulder & Elbow Roundup³⁶⁰ looks at: biceps, pressure and instability; chronic acromio-clavicular joint instability; depression and shoulder pain; shoulder replacement and transfusion; cuff integrity and function; iatropathic plexus injury; the accuracy of acromio-clavicular joint injection; and tennis as a risk factor for tennis elbow.

Adolescent idiopathic scoliosis affects about 3% of children. Non-operative measures are aimed at altering the natural history to maintain the size of the curve below 40° at skeletal maturity. The application of braces to treat spinal deformity pre-dates the era of evidence-based medicine, and there is a paucity of irrefutable prospective evidence in the literature to support their use and their effectiveness has been questioned.

This review considers this evidence. The weight of the evidence is in favour of bracing over observation. The most recent literature has moved away from addressing this question, and instead focuses on developments in the design of braces and ways to improve compliance.

Cite this article: Bone Joint J 2013;95-B:1308–16.

Patient-specific cutting guides (PSCGs) are designed to improve the accuracy of alignment of total knee replacement (TKR). We compared the accuracy of limb alignment and component positioning after TKR performed using PSCGs or conventional instrumentation. A total of 80 patients were randomised to undergo TKR with either of the different forms of instrumentation, and radiological outcomes and peri-operative factors such as operating time were assessed. No significant difference was observed between the groups in terms of tibiofemoral angle or femoral component alignment. Although the tibial component in the PSCGs group was measurably closer to neutral alignment than in the conventional group, the size of the difference was very small (89.8° (sd 1.2) vs 90.5° (sd 1.6); p = 0.030). This new technology slightly shortened the bone-cutting time by a mean of 3.6 minutes (p < 0.001) and the operating time by a mean 5.1 minutes (p = 0.019), without tangible differences in post-operative blood loss (p = 0.528) or need for blood transfusion (p = 0.789). This study demonstrated that both PSCGs and conventional instrumentation restore limb alignment and place the components with the similar accuracy. The minimal advantages of PSCGs in terms of consistency of alignment or operative time are unlikely to be clinically relevant.

Cite this article: Bone Joint J 2013;95-B:354–9.

We investigated the development of CT-based bony radiological parameters associated with femoroacetabular impingement (FAI) in a paediatric and adolescent population with no known orthopaedic hip complaints. We retrospectively reformatted and reoriented 225 abdominal CTs into standardised CT pelvic images with neutral pelvic tilt and inclination (244 female and 206 male hips) in patients ranging from two to 19 years of age (mean 10.4 years). The Tönnis angle, acetabular depth ratio, lateral centre–edge angle, acetabular version and α-angle were assessed.

Acetabular measurements demonstrated increased acetabular coverage with age and/or progressive ossification of the acetabulum. The α-angle decreased with age and/or progressive cortical bone development and resultant narrowing of the femoral neck. Cam and pincer morphology occurred as early as ten and 12 years of age, respectively, and their prevalence in the adolescent patient population is similar to that reported in the adult literature. Future aetiological studies of FAI will need to focus on the early adolescent population.

Cite this article: Bone Joint J 2013;95-B:598–604.

A comprehensive study of osteology remains a cornerstone of current orthopaedic and traumatological education. Osteology was already established as an important part of surgical education by the 16^th century. In order to teach anatomy and osteology, the corpses of executed criminals were dissected by the praelector anatomiae of the Amsterdam Guild of Surgeons. Magnificent anatomical atlases preserve the knowledge obtained from these dissections. We present an overview of the most authoritative works of Vesalius, Bidloo, Cheselden, and Albinus authored in the 16^th, 17^th and 18^th centuries. At that time a knowledge of osteology was necessary to pass the ‘master-exam’ in order to become a surgeon, and anatomical teaching was traditionally based on the practice of dissection. In the modern era, anatomical dissection and illustrations are largely being replaced by three-dimensional imaging and computer simulations, with an unfortunate trend in current curricula away from the established teaching technique of dissection. Education through the practice of dissection, particularly for future surgeons, remains integral to the development of tissue handling techniques, understanding of anatomical variation, and furthering of spatial awareness skills. With this review, we seek to remind contemporary surgeons of the lessons we can learn from our predecessors who valued education through anatomical dissection.

The aim of this study was to investigate the effect of laboratory-based simulator training on the ability of surgical trainees to perform diagnostic arthroscopy of the knee.

A total of 20 junior orthopaedic trainees were randomised to receive either a fixed protocol of arthroscopic simulator training on a bench-top knee simulator or no additional training. Motion analysis was used to assess performance objectively. Each trainee then received traditional instruction and demonstrations of diagnostic arthroscopy of the knee in theatre before performing the procedure under the supervision of a blinded consultant trainer. Their performance was assessed using a procedure-based assessment from the Orthopaedic Competence Assessment Project and a five-point global rating assessment scale.

In theatre the simulator-trained group performed significantly better than the untrained group using the Orthopaedic Competence Assessment Project score (p = 0.0007) and assessment by the global rating scale (p = 0.0011), demonstrating the transfer of psychomotor skills from simulator training to arthroscopy in the operating theatre. This has implications for the planning of future training curricula.

We compared the orientation of the acetabular component obtained by a conventional manual technique with that using five different navigation systems.

Three surgeons carried out five implantations of an acetabular component with each navigation system, as well as manually, using an anatomical model. The orientation of the acetabular component, including inclination and anteversion, and its position was determined using a co-ordinate measuring machine.

The variation of the orientation of the acetabular component was higher in the conventional group compared with the navigated group. One experienced surgeon took significantly less time for the procedure. However, his placement of the component was no better than that of the less experienced surgeons. Significantly better inclination and anteversion (p < 0.001 for both) were obtained using navigation. These parameters were not significantly different between the surgeons when using the conventional technique (p = 0.966).

The use of computer navigation helps a surgeon to orientate the acetabular component with less variation regarding inclination and anteversion.

We evaluated the oncological and functional outcome of 18 patients, whose malignant bone tumours were excised with the assistance of navigation, and who were followed up for more than three years. There were 11 men and seven women, with a mean age of 31.8 years (10 to 57). There were ten operations on the pelvic ring and eight joint-preserving limb salvage procedures. The resection margins were free of tumour in all specimens. The tumours, which were stage IIB in all patients, included osteosarcoma, high-grade chondrosarcoma, Ewing’s sarcoma, malignant fibrous histiocytoma of bone, and adamantinoma. The overall three-year survival rate of the 18 patients was 88.9% (95% confidence interval (CI) 75.4 to 100). The three-year survival rate of the patients with pelvic malignancy was 80.0% (95% CI 55.3 to 100), and of the patients with metaphyseal malignancy was 100%. The event-free survival was 66.7% (95% CI 44.9 to 88.5). Local recurrence occurred in two patients, both of whom had a pelvic malignancy. The mean Musculoskeletal Tumor Society functional score was 26.9 points at a mean follow-up of 48.2 months (22 to 79).

We suggest that navigation can be helpful during surgery for musculoskeletal tumours; it can maximise the accuracy of resection and minimise the unnecessary sacrifice of normal tissue by providing precise intra-operative three-dimensional radiological information.

Objectives

Orthopaedic surgeons use stems in revision knee surgery to obtain stability when metaphyseal bone is missing. No consensus exists regarding stem size or method of fixation. This in vitro study investigated the influence of stem length and method of fixation on the pattern and level of relative motion at the bone–implant interface at a range of functional flexion angles.

The aim of this study was to validate the use of three models of fracture fixation in the assessment of technical skills. We recruited 21 subjects (six experts, seven intermediates, and eight novices) to perform three procedures: application of a dynamic compression plate on a cadaver porcine model, insertion of an unreamed tibial intramedullary nail, and application of a forearm external fixator, both on synthetic bone models. The primary outcome measures were the Objective Structural Assessment of technical skills global rating scale on video recordings of the procedures which were scored by two independent expert observers, and the hand movements of the surgeons which were analysed using the Imperial College Surgical Assessment Device.

The video scores were significantly different for the three groups in all three procedures (p < 0.05), with excellent inter-rater reliability (α = 0.88). The novice and intermediate groups specifically were significantly different in their performance with dynamic compression plate and intramedullary nails (p < 0.05). Movement analysis distinguished between the three groups in the dynamic compression plate model, but a ceiling effect was demonstrated in the intramedullary nail and external fixator procedures, where intermediates and experts performed to comparable standards (p > 0.6). A total of 85% (18 of 21) of the subjects found the dynamic compression model and 57% (12 of 21) found all the models acceptable tools of assessment.

This study has validated a low-cost, high-fidelity porcine dynamic compression plate model using video rating scores for skills assessment and movement analysis. It has also demonstrated that Synbone models for the application of and intramedullary nail and an external fixator are less sensitive and should be improved for further assessment of surgical skills in trauma. The availability of valid objective tools of assessment of surgical skills allows further studies into improving methods of training.

Pigmented villonodular synovitis (PVNS) is a rare benign neoplastic proliferation of synovial tissue which is typically localised and usually responds well to surgery and/or radiotherapy. We present a case of unusually aggressive of PVNS of the hip in a 73-year-old woman.

The aim of this study was to investigate the effect of training on the arthroscopic performance of a group of medical students and to determine whether all students could be trained to competence. Thirty-three medical students with no previous experience of arthroscopy were randomised to a ‘Trained’ or an ‘Untrained’ cohort. They were required to carry out 30 episodes of two simulated arthroscopic tasks (one shoulder and one knee). The primary outcome variable was task success at each episode. Individuals achieved competence when their learning curve stabilised. The secondary outcome was technical dexterity, assessed objectively using a validated motion analysis system. Six subjects in the ‘Untrained’ cohort failed to achieve competence in the shoulder task, compared with one in the ‘Trained’ cohort. During the knee task, two subjects in each cohort failed to achieve competence. Based on the objective motion analysis parameters, the ‘Trained’ cohort performed better on the shoulder task (p < 0.05) but there was no significant difference for the knee task (p > 0.05).

Although specific training improved the arthroscopic performance of novices, there were individuals who could not achieve competence despite focused training.These findings may have an impact on the selection process for trainees and influence individual career choices.

The Morquio syndrome is a rare disorder which presents with a number of musculoskeletal problems. The literature describing total knee replacement in these patients is sparse. We describe the management of a patient with bilateral instability and pain in the knees using bilateral constrained knee replacements, and followed up for five years with pre- and postoperative knee scores. We highlight the difficulties encountered and discuss the end results.