Military static line parachute injuries in an Australian commando battalion.

BACKGROUND: The objective of this study was to define the casualty rates and anatomical distribution of injuries associated with military static line parachute (MSLP) descents conducted by an Australian Army Commando Battalion. This study was conducted to identify the strategies to reduce the injury burden related to MSLP activities. METHOD: A retrospective audit of injuries resulting from MSLP descents conducted by 4th Battalion Royal Australian Regiment (4 RAR) over a 13-month period. RESULTS: A total of 554 MSLP descents over the time period were reviewed. The overall casualty rate was 5.1%. For MSLP descents onto land drop zones, the incidence of injury requiring hospital admission was 2.6%. Paratrooper bodyweight was associated with increased risk of injury (P = 0.04) and hospital admission (P = 0.003), particularly when conducting descents onto land drop zones. MSLP descents conducted onto land were associated with a higher incidence of casualties when compared with those conducted into water drop zones (P = 0.001). CONCLUSION: During the period from February 2004 until February 2005, 4 RAR (Commando) experienced higher casualty rates during MSLP descents than expected when compared with the published report. Strategies to decrease the casualty rate of MSLP descents onto land drop zones may include more extensive ground training, increased frequency of MSLP descents, use of ankle braces and the development of purpose built drop zones. Consideration should be given to establishing a maximum bodyweight threshold for the conduct of MSLP activities or acquiring parachutes with decreased descent velocity for larger paratroopers.

Extraction of intramedullary nails by proximal stacked wire technique.

We describe the use of proximal stacked wires for the removal of an intramedullary nail in the context of difficult extraction and failed attempts by conventional methods. This percutaneous technique is particularly useful for the extraction of narrow cannulated or solid intramedullary nails after failure of removal by extraction bolt devices.

Shear properties of bilaminar polymethylmethacrylate cement mantles in revision hip joint arthroplasty.

Although cement-within-cement revision arthroplasty minimizes the complications associated with removal of secure PMMA, failure at the interfacial region between new and old cement mantles remains a theoretical concern. This article assesses the variability in shear properties of bilaminar cement mantles related to duration of postcure and the use of antibiotic cements. Bilaminar cement mantles were 15% to 20% weaker than uniform mantles (P < .001) and demonstrated variability in shear strength related to duration of postcure of the freshly applied cement (P < .001). The use of Antibiotic Simplex did not significantly influence interfacial cement adhesion (P = .52). Interfacial adhesion by mechanisms other than mechanical interlock plays a significant role in the bond formed between new and old PMMA cements, with an important contribution by diffusion-based molecular interdigitation. In the presence of a secure cement-bone interface, we recommend cement-within-cement revision techniques in suitable patients.

Early prosthetic complications after unipolar hemiarthroplasty.

BACKGROUND: In Australia, the most frequently used hemiarthroplasty prosthesis for the management of displaced intracapsular femoral neck fractures is the Uncemented Austin Moore (UAM). Despite concerns regarding poor functional outcomes and increased early revision rates associated with the UAM prosthesis, apprehension regarding the systemic side-effects of polymethylmethacrylate cement implantation in the elderly patient continues to influence prosthesis selection. This study examines the incidence of early prosthesis related complications after UAM and Cemented Thompson (CT) hemiarthroplasty procedures for the management of femoral neck fractures. METHODS: A multicentre retrospective review of charts and radiographs was conducted in 1118 unipolar hemiarthroplasty implantations to determine early complications associated with the CT and UAM prostheses over a 6-year period in five Queensland public hospitals. RESULTS: Intraoperative periprosthetic fractures were sustained in 11.8% of UAM and 1.8% of CT implantations (P < 0.0001). Intraoperative periprosthetic fractures were associated with an increased requirement for reoperation within 1 month of the index procedure (P = 0.05). No statistical difference in the incidence of intraoperative periprosthetic fractures could be observed between the hospitals participating, regardless of the proportional use of each prosthesis. Early dislocation rates were similar for the UAM and CT prostheses. The intraoperative mortality rate attributable to the use of polymethylmethacrylate cement during hip hemiarthroplasty was 1/738 (0.14%). CONCLUSIONS: The results of this study support the use of the CT prosthesis for the management of femoral neck fractures to reduce the high incidence of intraoperative periprosthetic fractures and associated requirements for early reoperation experienced with the UAM.