Aims

Bone demonstrates good healing capacity, with a variety of strategies being utilized to enhance this healing. One potential strategy that has been suggested is the use of stem cells to accelerate healing.

Tendinopathy is a debilitating musculoskeletal condition which can cause significant pain and lead to complete rupture of the tendon, which often requires surgical repair. Due in part to the large spectrum of tendon pathologies, these disorders continue to be a clinical challenge. Animal models are often used in this field of research as they offer an attractive framework to examine the cascade of processes that occur throughout both tendon pathology and repair. This review discusses the structural, mechanical, and biological changes that occur throughout tendon pathology in animal models, as well as strategies for the improvement of tendon healing.

Cite this article: Bone Joint Res 2014;3:193–202.

Nanotechnology is the study, production and controlled manipulation of materials with a grain size < 100 nm. At this level, the laws of classical mechanics fall away and those of quantum mechanics take over, resulting in unique behaviour of matter in terms of melting point, conductivity and reactivity. Additionally, and likely more significant, as grain size decreases, the ratio of surface area to volume drastically increases, allowing for greater interaction between implants and the surrounding cellular environment. This favourable increase in surface area plays an important role in mesenchymal cell differentiation and ultimately bone–implant interactions.

Basic science and translational research have revealed important potential applications for nanotechnology in orthopaedic surgery, particularly with regard to improving the interaction between implants and host bone. Nanophase materials more closely match the architecture of native trabecular bone, thereby greatly improving the osseo-integration of orthopaedic implants. Nanophase-coated prostheses can also reduce bacterial adhesion more than conventionally surfaced prostheses. Nanophase selenium has shown great promise when used for tumour reconstructions, as has nanophase silver in the management of traumatic wounds. Nanophase silver may significantly improve healing of peripheral nerve injuries, and nanophase gold has powerful anti-inflammatory effects on tendon inflammation.

Considerable advances must be made in our understanding of the potential health risks of production, implantation and wear patterns of nanophase devices before they are approved for clinical use. Their potential, however, is considerable, and is likely to benefit us all in the future.

Cite this article: Bone Joint J 2014; 96-B: 569–73.

The ability of mesenchymal stem cells (MSCs) to differentiate in vitro into chondrocytes, osteocytes and myocytes holds great promise for tissue engineering. Skeletal defects are emerging as key targets for treatment using MSCs due to the high responsiveness of bone to interventions in animal models. Interest in MSCs has further expanded in recognition of their ability to release growth factors and to adjust immune responses. Despite their increasing application in clinical trials, the origin and role of MSCs in the development, repair and regeneration of organs have remained unclear. Until recently, MSCs could only be isolated in a process that requires culture in a laboratory; these cells were being used for tissue engineering without understanding their native location and function. MSCs isolated in this indirect way have been used in clinical trials and remain the reference standard cellular substrate for musculoskeletal engineering. The therapeutic use of autologous MSCs is currently limited by the need for ex vivo expansion and by heterogeneity within MSC preparations. The recent discovery that the walls of blood vessels harbour native precursors of MSCs has led to their prospective identification and isolation. MSCs may therefore now be purified from dispensable tissues such as lipo-aspirate and returned for clinical use in sufficient quantity, negating the requirement for ex vivo expansion and a second surgical procedure. In this annotation we provide an update on the recent developments in the understanding of the identity of MSCs within tissues and outline how this may affect their use in orthopaedic surgery in the future. Cite this article: Bone Joint J 2014;96-B:291–8

Hyaline articular cartilage has been known to be a troublesome tissue to repair once damaged. Since the introduction of autologous chondrocyte implantation (ACI) in 1994, a renewed interest in the field of cartilage repair with new repair techniques and the hope for products that are regenerative have blossomed. This article reviews the basic science structure and function of articular cartilage, and techniques that are presently available to effect repair and their expected outcomes.

Adult presentation of neglected congenital muscular torticollis is rare. We report 12 patients with this condition who underwent a modified Ferkel’s release comprising a bipolar release of sternocleidomastoid with Z-lengthening. They had a mean age of 24 years (17 to 31) and were followed up for a minimum of two years. Post-operatively a cervical collar was applied for three weeks with intermittent supervised active assisted exercises for six weeks. Outcome was assessed using a modified Lee score and a Cheng and Tang score. The mean pre-operative rotational deficit was 8.25° (0° to 15°) and mean lateral flexion deficit was 20.42° (15° to 30°), which improved after treatment to a mean of 1.67° (0° to 5°) and 7.0° (4° to 14°) after treatment, respectively. According to the modified Lee scoring system, six patients had excellent results, two had good results and four had fair results, and using the Cheng and Tang score, eight patients had excellent results and four had good results.

Surgical management of adult patients with neglected congenital muscular torticollis using a modified Ferkel’s bipolar release gives excellent results. The range of neck movement and head tilt improved in all 12 patients and cosmesis improved in 11, despite the long-standing nature of the deformity.

Clinical, haematological or economic benefits of post-operative blood salvage with autologous blood re-transfusion have yet to be clearly demonstrated for primary total hip replacement. We performed a prospective randomised study to analyse differences in postoperative haemoglobin levels and homologous blood requirements in two groups of patients undergoing primary total hip replacement. A series of 158 patients was studied. In one group two vacuum drains were used and in the other the ABTrans autologous retransfusion system. A total of 58 patients (76%) in the re-transfusion group received autologous blood. There was no significant difference in the mean post-operative haemoglobin levels in the two groups. There were, however, significantly fewer patients with post-operative haemoglobin values less than 9.0 g/dl and significantly fewer patients who required transfusion of homologous blood in the re-transfusion group. There was also a small overall cost saving in this group

Using a computer-based quality assurance program, we analysed peri-operative data on 160 patients undergoing one-stage bilateral hip or knee arthroplasties under regional anaesthesia with routine anaesthetic monitoring and only using peripheral intravenous access for peri-operative safety. We monitored defined intra-operative adverse events such as hypotension, myocardial ischaemia, arrhythmias, hypovolaemia, hypertension and early post-operative complications. We also determined post-operative hip and knee function, and patient satisfaction with different aspects of the anaesthetic management. Those patients undergoing one-stage bilateral arthroplasties were matched according to a cross-stratification which used three variables (American Society of Anesthesiologists’ physical status scoring system, age and joint replaced) to patients undergoing unilateral hip or knee arthroplasties. Serious intra-operative adverse events were, with the exception of intra-operative hypotension, very infrequent in patients undergoing bilateral (nine adverse events) as well as unilateral arthroplasties (five adverse events). Early post-operative complications were also infrequent in both groups. However, the risks of receiving a heterologous blood transfusion (odds ratio 2.5; 95% confidence interval (CI) 1.3 to 5.0, estimated by exact conditional logistic regression) or vasoactive drugs (odds ratio 3.9; 95% CI 2.0 to 7.8) were significantly greater for patients undergoing bilateral operations. Patient satisfaction with anaesthesia was high; all patients who underwent the one-stage bilateral operation would choose the same anaesthetic technique again.

We prospectively audited 79 patients undergoing primary knee or hip arthroplasty (38 knees, 41 hips) and found that 66% (58% of knees, 73% of hips) had at least one unit of blood transfused postoperatively, with a mean transfusion requirement of 1.3 units per patient (1.1 for knees, 0 to 6; 1.5 for hips, 0 to 4). We then established a new protocol for postoperative blood transfusion. This requires the calculation of the maximum allowable blood loss (MABL) that each individual patient can safely lose based upon their weight and preoperative haematocrit. The total blood loss up to this volume is replaced with colloid. When a patient’s total blood loss reaches their MABL their haematocrit is measured at the bedside using the Microspin system (Bayer plc, Newbury, UK). If their haematocrit is low (< 0.30 for men, < 0.27 for women), blood is transfused. As a safety net all patients have their haemoglobin formally checked on days 1, 2, and 3 after surgery and have a transfusion if the haemoglobin levels are less than 8.5 g/dl. We conducted a further audit of 82 patients (35 knees, 47 hips) after the introduction of this protocol. Under the new protocol only 24% of patients required blood (11% of knees, 34% of hips) with a mean transfusion requirement of 0.56 units per patient (0.26 for knees, 0 to 4; 0.79 for hips, 0 to 4). The use of clinical audit and the introduction of strict guidelines for transfusion can change transfusion practice and result in improved patient care. Our transfusion protocol is a simple and effective method of keeping transfusion to a minimum and is particularly useful in departments which do not have the facility to use autologous blood or reinfusion drains for elective orthopaedic surgery