The June 2012 Research Roundup³⁶⁰ looks at: platelet-rich plasma; ageing, bone and mesenchymal stem cells; cytokines and the herniated intervertebral disc; ulcerative colitis, Crohn’s disease and anti-inflammatories; the effect of NSAIDs on bone healing; osteoporosis of the fractured hip; herbal medicine and recovery after acute muscle injury; and ultrasound and the time to fracture union.

The aim of this study was to determine the accuracy of registration and the precision of the resection volume in navigated hip arthroscopy for cam-type femoroacetabular impingement, using imageless and image-based registration. A virtual cam lesion was defined in 12 paired cadaver hips and randomly assigned to either imageless or image-based (three-dimensional (3D) fluoroscopy) navigated arthroscopic head–neck osteochondroplasty. The accuracy of patient–image registration for both protocols was evaluated and post-operative imaging was performed to evaluate the accuracy of the surgical resection. We found that the estimated accuracy of imageless registration in the arthroscopic setting was poor, with a mean error of 5.6 mm (standard deviation (sd) 4.08; 95% confidence interval (CI) 4.14 to 7.19). Because of the significant mismatch between the actual position of the probe during surgery and the position of that probe as displayed on the navigation platform screen, navigated femoral osteochondroplasty was physically impossible. The estimated accuracy of image-based registration by means of 3D fluoroscopy had a mean error of 0.8 mm (sd 0.51; 95% CI 0.56 to 0.94). In terms of the volume of bony resection, a mean of 17% (sd 11; -6% to 28%) more bone was resected than with the virtual plan (p = 0.02). The resection was a mean of 1 mm deeper (sd 0.7; -0.3 to 1.6) larger than on the original virtual plan (p = 0.02).

In conclusion, given the limited femoral surface that can be reached and digitised during arthroscopy of the hip, imageless registration is inaccurate and does not allow for reliable surgical navigation. However, image-based registration does acceptably allow for guided femoral osteochondroplasty in the arthroscopic management of femoroacetabular impingement.

Infection of a total hip replacement (THR) requires component removal and thorough local debridement. Usually, long-term antibiotic treatment in conjunction with a two-stage revision is required. This may take several months. One-stage revision using antibiotic-loaded cement has not gained widespread use, although the clinical and economic advantages are obvious. Allograft bone may be impregnated with high levels of antibiotics, and in revision of infected THR, act as a carrier providing a sustained high local concentration.

We performed 37 one-stage revision of infected THRs, without the use of cement. There were three hips which required further revision because of recurrent infection, the remaining 34 hips (92%) stayed free from infection and stable at a mean follow-up of 4.4 years (2 to 8). No adverse effects were identified. Incorporation of bone graft was comparable with unimpregnated grafts.

Antibiotic-impregnated allograft bone may enable reconstruction of bone stock, insertion of an uncemented implant and control of infection in a single operation in revision THR for infection.

We systematically reviewed all the evidence published in the English language on proximal interphalangeal joint (PIPJ) replacement, to determine its effectiveness on the function of the hand and the associated post-operative complications.

Original studies were selected if they reported clinical outcome with a minimum of one year’s follow-up. Quality was assessed using the Cowley systematic review criteria modified for finger-joint replacements. Of 319 articles identified, only five were adequately reported according to our quality criteria; there were no randomised controlled trials. PIPJ replacements had a substantial effect size on hand pain of -23.2 (95% confidence interval (CI) -27.3 to -19.1) and grip strength 1.2 (95% CI -10.7 to 13.1), and a small effect on range of movement 0.2 (95% CI -0.4 to 0.8). A dorsal approach was most successful. Post-operative loosening occurred in 10% (95% CI 3 to 30) of ceramic and 12.5% (95% CI 7 to 21) of pyrocarbon replacements. Post-operative complications occurred in 27.8% (95% CI 20 to 37).

We conclude that the effectiveness of PIPJ replacement has not been established. Small observational case studies and short-term follow-up, together with insufficient reporting of patient data, functional outcomes and complications, limit the value of current evidence.

We recommend that a defined core set of patients, surgical and outcome data for this intervention be routinely and systematically collected within the framework of a joint registry.

Most patients (95%) with fibular hemimelia have an absent anterior cruciate ligament (ACL). The purpose of this study was to assess the long-term outcome of such patients with respect to pain and knee function. We performed a retrospective review of patients with fibular hemimelia and associated ACL deficiency previously treated at our institution. Of a possible 66 patients, 23 were sent the Musculoskeletal Outcomes Data Evaluation and Management System (MODEMS) questionnaire and Lysholm knee score to complete. In all, 11 patients completed the MODEMS and nine completed the Lysholm score questionnaire. Their mean age was 37 years (27 to 57) at review. Five patients had undergone an ipsilateral Symes amputation. There was no significant difference in any subsections of the Short-Form 36 scores of our patients compared with age-matched controls. The mean Lysholm knee score was 90.2 (82 to 100). A slight limp was reported in six patients. No patients had episodes of locking of the knee or required a supportive device for walking. Four had occasional instability with sporting activities.

These results suggest that patients with fibular hemimelia and ACL deficiency can live active lives with a similar health status to age-matched controls.

Objectives

We aimed to further evaluate the biomechanical characteristics of two locking screws versus three standard bicortical screws in synthetic models of normal and osteoporotic bone.

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.

The success of long-term transcutaneous implants depends on dermal attachment to prevent downgrowth of the epithelium and infection. Hydroxyapatite (HA) coatings and fibronectin (Fn) have independently been shown to regulate fibroblast activity and improve attachment. In an attempt to enhance this phenomenon we adsorbed Fn onto HA-coated substrates. Our study was designed to test the hypothesis that adsorption of Fn onto HA produces a surface that will increase the attachment of dermal fibroblasts better than HA alone or titanium alloy controls.

Iodinated Fn was used to investigate the durability of the protein coating and a bioassay using human dermal fibroblasts was performed to assess the effects of the coating on cell attachment. Cell attachment data were compared with those for HA alone and titanium alloy controls at one, four and 24 hours. Protein attachment peaked within one hour of incubation and the maximum binding efficiency was achieved with an initial droplet of 1000 ng. We showed that after 24 hours one-fifth of the initial Fn coating remained on the substrates, and this resulted in a significant, three-, four-, and sevenfold increase in dermal fibroblast attachment strength compared to uncoated controls at one, four and 24 hours, respectively.

We report our early experience with a new peri-acetabular reconstruction endoprosthesis used for pelvic reconstruction after tumour resection. The outcome of 21 patients who underwent limb salvage following type II pelvic resection and reconstruction using the peri-acetabular reconstruction prosthesis between 2000 and 2006 was retrospectively reviewed. This prosthesis was designed to use the remaining part of the ilium to support a horizontally placed acetabular component secured with internal fixation and bone cement. Into this device a constrained acetabular liner is positioned which is articulates with a conventional femoral component to which a modular extension and modular head are attached. The mean follow-up was 20.5 months (1 to 77). The most common complications were deep infection, superficial wound infections, and dislocation. The mean musculoskeletal tumor society functional outcome score for the survivors was 20.1(11 to 27).

We recommend the use of the peri-acetabular reconstruction prosthesis for reconstruction of large defects after type II pelvic resection, as this design has a greater inherent stability over other available prostheses.

We retrospectively compared the outcome after the treatment of giant cell tumours of bone either with curettage alone or with adjuvant cementation. Between 1975 and 2008, 330 patients with a giant cell tumour were treated primarily by intralesional curettage, with 84 (25%) receiving adjuvant bone cement in the cavity. The local recurrence rate for curettage alone was 29.7% (73 of 246) compared with 14.3% (12 of 84) for curettage and cementation (p = 0.001). On multivariate analysis both the stage of disease and use of cement were independent significant factors associated with local recurrence. The use of cement was associated with a higher risk of the subsequent need for joint replacement. In patients without local recurrence, 18.1% (13 of 72) of those with cement needed a subsequent joint replacement compared to 2.3% (4 of 173) of those without cement (p = 0.001). In patients who developed local recurrence, 75.0% (9 of 12) of those with previous cementation required a joint replacement, compared with 45.2% (33 of 73) of those without cement (p = 0.044).

Objectives

The Oxford hip score (OHS) is a 12-item questionnaire designed and developed to assess function and pain from the perspective of patients who are undergoing total hip replacement (THR). The OHS has been shown to be consistent, reliable, valid and sensitive to clinical change following THR. It has been translated into different languages, but no adequately translated, adapted and validated Danish language version exists.

Robots have been used in surgery since the late 1980s. Orthopaedic surgery began to incorporate robotic technology in 1992, with the introduction of ROBODOC, for the planning and performance of total hip replacement. The use of robotic systems has subsequently increased, with promising short-term radiological outcomes when compared with traditional orthopaedic procedures. Robotic systems can be classified into two categories: autonomous and haptic (or surgeon-guided). Passive surgery systems, which represent a third type of technology, have also been adopted recently by orthopaedic surgeons.

While autonomous systems have fallen out of favour, tactile systems with technological improvements have become widely used. Specifically, the use of tactile and passive robotic systems in unicompartmental knee replacement (UKR) has addressed some of the historical mechanisms of failure of non-robotic UKR. These systems assist with increasing the accuracy of the alignment of the components and produce more consistent ligament balance. Short-term improvements in clinical and radiological outcomes have increased the popularity of robot-assisted UKR.

Robot-assisted orthopaedic surgery has the potential for improving surgical outcomes. We discuss the different types of robotic systems available for use in orthopaedics and consider the indication, contraindications and limitations of these technologies.

We identified 16 patients with a mean age of 56.5 years (31 to 86) from a large consecutive series of patients with proximal humeral fractures over a 15-year period, who had sustained a fracture with skin compromise after a blunt injury. The study group represented 0.2% of 7825 proximal humeral fractures treated during this period and all had a displaced Neer two-part fracture pattern. Two patterns of skin injury were identified: in ten patients there was skin penetration at the time of the original injury, and the other six patients initially had closed injuries. These six patients had fracture fragments penetrating the muscular envelope to lie subcutaneously producing either early skin tethering (two patients) or delayed skin penetration and sinus formation (four patients). The pattern of injury to the soft-tissue envelope and the fracture pattern were similar for all injuries. Treatment of these injuries was determined by the initial severity of the soft-tissue injury and the medical status of the patient. We currently favour open reduction and internal fixation of these fractures wherever possible, owing to the high rate of nonunion with non-operative management.

Isolated fractures of the anterior column and anterior wall are a relatively rare subgroup of acetabular fractures. We report our experience of 30 consecutive cases treated over ten years. Open reduction and internal fixation through an ilioinguinal approach was performed for most of these cases (76.7%) and percutaneous techniques were used for the remainder. At a mean follow-up of four years (2 to 6), 26 were available for review. The radiological and functional outcomes were good or excellent in 23 of 30 patients (76.7%) and 22 of 26 patients (84.6%) according to Matta’s radiological criteria and the modified Merlé d’Aubigné score, respectively.

Complications of minor to moderate severity were seen in six of the 30 cases (20%) and none of the patients underwent secondary surgery or replacement of the hip.

Femoroacetabular cam impingement is thought to be a cause of premature osteoarthritis of the hip.

The presence of cam malformation was determined in 2803 standardised anteroposterior (AP) pelvic radiographs from the Copenhagen Osteoarthritis Study by measuring the alpha (α) angle and the triangular index, a new measure of asphericity of the femoral head. In addition, the α-angle and the triangular index were assessed on the AP and lateral hip radiographs of 82 men and 82 women randomly selected from patients scheduled for total hip replacement (THR). The influence of varying femoral rotation on the α angle and the triangular index was also determined in femoral specimens under experimental conditions.

From the 2803 radiographs the mean AP α-angle was 55° (30° to 100°) in men and 45° (34° to 108°) in women. Approximately 6% of men and 2% of women had cam malformation. The α-angle and triangular index were highly inter-related. Of those patients scheduled for THR, 36 men (44%) and 28 women (35%) had cam malformation identifiable on the AP radiographs. The triangular index proved to be more reliable in detecting cam malformation when the hip was held in varying degrees of rotation.

The combination of the α-angle and the triangular index will allow examination of historical radiographs for epidemiological purposes in following the natural history of the cam deformity.

We retrospectively studied 14 patients with proximal and diaphyseal tumours and disappearing bone (Gorham’s) disease of the humerus treated with wide resection and reconstruction using an allograft-resurfacing composite (ARC). There were ten women and four men, with a mean age of 35 years (8 to 69). At a mean follow-up of 25 months (10 to 89), two patients had a fracture of the allograft. In one of these it was revised with a similar ARC and in the other with an intercalary prosthesis. A further patient had an infection and a fracture of the allograft that was revised with a megaprosthesis. In all patients with an ARC, healing of the ARC-host bone interface was observed. One patient had failure of the locking mechanism of the total elbow replacement. The mean post-operative Musculoskeletal Tumor Society score for the upper extremity was 77% (46.7% to 86.7%), which represents good and excellent results; one patient had a poor result (46.7%).

In the short term ARC effectively relieves pain and restores shoulder function in patients with wide resection of the proximal humerus. Fracture and infection remain significant complications.

The presacral retroperitoneal approach for axial lumbar interbody fusion (presacral ALIF) is not widely reported, particularly with regard to the mid-term outcome. This prospective study describes the clinical outcomes, complications and rates of fusion at a follow-up of two years for 26 patients who underwent this minimally invasive technique along with further stabilisation using pedicle screws. The fusion was single-level at the L5-S1 spinal segment in 17 patients and two-level at L4–5 and L5-S1 in the other nine. The visual analogue scale for pain and Oswestry Disability Index scores were recorded pre-operatively and during the 24-month study period. The evaluation of fusion was by thin-cut CT scans at six and 12 months, and flexion-extension plain radiographs at six, 12 and 24 months. Significant reductions in pain and disability occurred as early as three weeks postoperatively and were maintained. Fusion was achieved in 22 of 24 patients (92%) at 12 months and in 23 patients (96%) at 24 months. One patient (4%) with a pseudarthrosis underwent successful revision by augmentation of the posterolateral fusion mass through a standard open midline approach.

There were no severe adverse events associated with presacral ALIF, which in this series demonstrated clinical outcomes and fusion rates comparable with those of reports of other methods of interbody fusion.

Coloured bone cements have been introduced to make the removal of cement debris easier at the time of primary and revision joint replacement. We evaluated the physical, mechanical and pharmacological effects of adding methylene blue to bone cement with or without antibiotics (gentamicin, vancomycin or both). The addition of methylene blue to plain cement significantly decreased its mean setting time (570 seconds (sd 4) vs 775 seconds (sd 11), p = 0.01), mean compression strength (95.4 MPa (sd 3) vs 100.1 MPa (sd 6), p = 0.03), and mean bending strength (65.2 MPa (sd 5) vs 76.6 MPa (sd 4), p < 0.001) as well as its mean elastic modulus (2744 MPa (sd 97) vs 3281 MPa (sd 110), p < 0.001). The supplementation of the coloured cement with vancomycin and gentamicin decreased its mean bending resistance (55.7 MPa (sd 4) vs 65.2 MPa (sd 5), p < 0.001).The methylene blue significantly decreased the mean release of gentamicin alone (228.2 µg (sd 24) vs 385.5 µg (sd 26), p < 0.001) or in combination with vancomycin (498.5 µg (sd 70) vs 613 µg (sd 25), p = 0.018) from the bone cement. This study demonstrates several theoretical disadvantages of the antibiotic-loaded bone cement coloured with methylene blue.

We retrospectively reviewed the hospital records of 68 patients who had been referred with an injury to the posterolateral corner of the knee to a specialist knee surgeon between 2005 and 2009. These injuries were diagnosed based on a combination of clinical testing and imaging and arthroscopy when available. In all, 51 patients (75%) presented within 24 hours of their injury with a mean presentation at eight days (0 to 20) after the injury. A total of 63 patients (93%) had instability of the knee at presentation. There was a mean delay to the diagnosis of injury to the posterolateral corner of 30 months (0 to 420) from the time of injury. In all, the injuries in 49 patients (72%) were not identified at the time of the initial presentation, with the injury to the posterolateral corner only recognised in those patients who had severe multiple ligamentous injuries. The correct diagnosis, including injury to the posterolateral corner, had only been made in 34 patients (50%) at time of referral to a specialist knee clinic. MRI correctly identified 14 of 15 injuries when performed acutely (within 12 weeks of injury), but this was the case in only four of 15 patients in whom it was performed more than 12 weeks after the injury.

Our study highlights a need for greater diligence in the examination and investigation of acute ligamentous injuries at the knee with symptoms of instability, in order to avoid failure to identify the true extent of the injury at the time when anatomical repair is most straightforward.