<b>INTRODUCTIONb>Hip hemiarthoplasties are commonly performed for displaced femoral neck fractures. Considerable differences of opinion exists regarding the choice between unipolar and bipolar designs. The main theoretical advantage of a bipolar over a unipolar prosthesis is the reduction of acetabular erosion due to movement taking place within the implant rather than at the acetabular implant interface. It is thus hypothesised that bipolar prostheses lead to better long-term functional outcomes with less complications. In this study, we aimed to compare unipolar (Moore's) and bipolar hemiarthroplasty looking specifically for differences in 1) pain and functional hip scores; 2) rates of acetabular erosion, component migration and revision surgery; and 3) rates of postoperative morbidity.

<b>MATERIALS AND METHODSb>Inclusion criteria were 1) age more than or equal to 65 years; 2) displaced femoral neck fracture of non-pathologic origin; 3) normal cognitive function; 4) ambulatory with or without assistive devices prior to the fracture; and 5) treated with a primary prosthetic replacement. Of the 193 patients that were available for review, 118 were in the Moore's group and 75 in the bipolar group. Postoperatively, patients were assessed with regards to pain, satisfaction, Modified Harris hip score and Oxford hip score. Standard anteroposterior pelvis and lateral hip radiographs were obtained at regular intervals. These were analysed specifically with regards to acetabular erosion and component migration.

<b>RESULTSb>There was no significant difference between a Moore's and a bipolar prosthesis regarding hip pain, functional hip scores, rates of acetabular erosion, component migration, revision surgery and complications rates.

<b>CONCLUSIONb>Use of the more expensive bipolar prosthesis in elderly and premorbidly ambulant patient is not justified.

Age Factors ; Aged ; Aged, 80 and over ; Arthroplasty, Replacement, Hip ; instrumentation ; Female ; Femoral Neck Fractures ; surgery ; Hemiarthroplasty ; instrumentation ; Hip Prosthesis ; Humans ; Male ; Postoperative Complications ; epidemiology ; Prosthesis Design ; Prosthesis Failure ; Reoperation ; Treatment Outcome

<b>INTRODUCTIONb>Most current cell-based cartilage repair techniques require some form of scaffolds and 2 separate surgical procedures. We propose a novel, scaffold-less technique of cartilage repair in the human knee that combines arthroscopic microfracture and outpatient intra-articular injections of autologous bone marrow-derived mesenchymal stem cells (MSCs) and hyaluronic acid (HA).

<b>MATERIALS AND METHODSb>Seventy matched (age, sex, lesion size) knees with symptomatic cartilage defects underwent cartilage repair with the proposed technique (n = 35) or an open technique (n = 35) in which the MSCs were implanted beneath a sutured periosteal patch over the defect. Prospective evaluation of both groups were performed using the International Cartilage Repair Society (ICRS) Cartilage Injury Evaluation Package, which included questions from the Short-Form (SF-36) Health Survey, International Knee Documentation Committee (IKDC) subjective knee evaluation form, Lysholm knee scale, and Tegner activity level scale. Postoperative magnetic resonance imaging (MRI) evaluation was also performed at 1 year for most patients.

<b>RESULTSb>There were no clinically significant adverse events reported through the course of our study. At the fi nal follow-up (mean = 24.5 months), there was significant improvement in mean IKDC, Lysholm, SF-36 physical component score and visual analogue pain scores in both treatment groups.

<b>CONCLUSIONb>In the short term, the results of this novel technique are comparable to the open procedure with the added advantages of being minimally invasive and requiring only a single operation under general anaesthesia. Its safety has been validated and its efficacy is currently being evaluated in an ongoing randomised controlled trial.

Adult ; Arthroscopy ; methods ; Cartilage, Articular ; injuries ; Combined Modality Therapy ; methods ; Female ; Humans ; Hyaluronic Acid ; therapeutic use ; Knee Injuries ; therapy ; Magnetic Resonance Imaging ; Male ; Mesenchymal Stem Cell Transplantation ; methods ; Outcome Assessment (Health Care) ; Patient Safety ; Prospective Studies ; Singapore ; Viscosupplements ; therapeutic use