The aim of the study was to assess the medium term outcome for complex proximal humeral fractures treated with the long proximal humeral internal locking system (PHILOS) plate fixation. All patients who had long PHILOS plate fixation of proximal humerus fractures with metaphyseal or diaphyseal extension over a three year period at our institution were included in the study. Patients had their case notes and radiographs reviewed. Patients were also contacted to assess functional outcome using the Visual Analogue Scale (VAS) for pain, DASH, Oxford shoulder score (OSS) and Stanmore Percentage of Normal Shoulder Assessment (SPONSA). Out of an initial cohort of 34 patients, 1 died, 2 patients had unrelated illnesses resulting in them being unable to complete the assessment and 6 were lost to follow-up, leaving 25 patients (74%) for review. All patients had proximal humeral fractures with metaphyseal or diaphyseal extension requiring long plate osteosynthesis. One patient had the procedure for non union following initial treatment with an intra medullary nail and the rest were acute injuries. The patients were followed up after a mean of 27 months (range 11–60). The length of plate used varied from 5 to 12 holes for the shaft region. There was 1 wound infection. 3 patients had non unions which required bone grafting and revision internal fixation. At final follow-up, mean pain was 3.6 (95% Confidence Interval 2.5–4.8) with only 4 patients having residual pain greater than 5 on the VAS scale. Mean DASH score was 41.2 (95% CI 32.0–50.4), mean OSS was 29.1 (95% CI 24.3–33.9) and mean SPONSA was 63.9% (95% CI 50.8–77.2) The long PHILOS plate appears to represent a good treatment option for complex proximal humerus fractures with favourable medium term results and few complications.
The aim of the study was to assess the rate of greater tuberosity non union in reverse shoulder arthroplasty performed for proximal humerus fractures and to assess if union is related to type of fracture or the intraoperative reduction of the greater tuberosity. All cases of reverse shoulder arthroplasty for proximal humerus fractures at our institution over a three year period were retrospectively reviewed from casenotes and radiologically and the position of the greater tuberosity was documented at immediate post op, 6 months and 12 months. Any malunion or non union were noted. A total of 27 cases of reverse shoulder arthroplasty for proximal humeral fractures were identified. 4 cases did not have complete follow up xrays and were excluded from analysis. The average age at operation of the cohort of the 23 remaining patients was 79 years (range 70–91). The greater tuberosity was anatomically well positioned intraoperatively in 17 of the 23 cases. At the end of 12 months there were 4 cases of tuberosity non union (17%), all except one occurring in poorly intraoperatively positioned greater tuberosity. 50% (3 out of 6) of greater tuberosities displaced further and remained ununited if the intraoperative position was poor. Only 6% (1 out of 17) greater tuberosities did not unite if the greater tuberosities was reduced anatomically. Intra operatively position of the greater tuberosity was strongly associated with their union (Fischer's exact test p<0.05). Union of greater tuberosity was not statistically associated with fracture pattern (Fischer's exact test p=0.48). Our case series show a low rate of tuberosity malunion after reverse shoulder arthroplasty for proximal humerus fracture. Good positioning and fixation of the greater tuberosity intra operatively is a strong predictor of their uneventful union to shaft.
Recent concerns over adverse effects of metal ion release, have led to the development of alternative hip joint replacements. This study reports the performance of new hemispherical MOTIS® (milled pitch-carbon fibre reinforced polyetheretherketone) acetabular cups articulating against Biolox Delta® femoral heads with the aim of producing lower wear and more biologically compatible bearings. The wear performance of 40mm hemispherical MOTIS® cups articulating against Biolox Delta® heads has been investigated. The diametral clearance was 322±15.3nm (mean ± standard deviation). Wear tests were carried out on the Simplified Mark II Durham Hip Wear Simulator to 8 million cycles. New born bovine calf serum was used as the lubricant, diluted to give a protein content of 17g/l. Friction tests were carried out on the unworn joints and worn joints after 7.5 million cycles using lubricants containing protein (bovine serum based carboxymethyl cellulose (CMC) fluids) and without protein (water based CMC fluids). Temperature measured near every hip joint over a continuous wear testing period of 0.5 million cycles was recorded using PICO TC-08 data logger. One K-type thermocouple was placed carefully and consistently in each wear station and two were used to record the ambient room temperature. After stopping the wear test, the data logger continued recording the temperature for a further ten hours to indicate the cooling period. Additionally surface analyses were undertaken before and after wear testing using a non-contacting profilometer and atomic force (AFM) microscope.Introduction
Materials and Methods
R Appleyard, Murray Maxwell Biomechanics Lab, Royal North Shore Hospital, Sydney The fundamental mechanisms that underlie tendon breakdown are ill understood. There is an emerging hypothesis that altered mechanical strain modulates the metabolism and/or phenotype of tenocytes, disrupting the balance of matrix synthesis and degradation, and that rupture then occurs through an abnormal tendon matrix. The critically regulated genes have not yet been determined. We have developed sheep model in sheep where both stress-deprived and over-stressed areas can be examined in the one tendon, to evaluate the pathological and molecular changes over time. We have also used ‘wild type’ and genetically modified mice to determine the role of specific enzymes and proteoglycans in tendon degeneration. Stress-deprived and over-stressed regions showed classical changes of increased cellularity and vascularity, rounded tenocytes and interfascicular matrix infiltration. These structural changes resolved for up to one year after injury. Resolution was more rapid in over-stressed regions. Irrespective of the initiating stress, proteoglycan staining and chondroid metaplasia increased in tendon with time. There were distinct molecular and temporal differences between regions, which are reviewed here. While tendon degeneration has traditionally been regarded as a single field of change, our studies show that at a molecular level, the injured tendon may be regarded as a number of distinct regions—overloaded and underloaded, adjacent to bone or adjacent to muscle. Each region manifests distinct molecular changes, driven by relevant gene expression. While collagen metabolism in pathological tendon has received much attention, accumulation of proteoglycan is also consistently induced by altered mechanical loading. We suggest that ADAMTS enzymes, which cleave aggrecan, versican and small proteoglycans, may play a significant role in tendon homeostasis and pathology. Regulating proteoglycan turnover may represent a novel target for treating tendon degeneration. We have initiated studies using mesenchymal stem cells (MSC), not to directly augment healing but to modify the molecular pathology in tendon resulting from altered loading. Preliminary data indicates that injection of MSC into an acute tendon defect significantly abrogates the increase in expression of aggrecan and collagen degrading metalloproteinases in the adjacent over-stressed tendon. This may decrease the resultant degeneration. The effects of MSC in treating tendon degeneration are reviewed here, as are the possible benefits of radiofrequency microtenotomy.
