Wakefield Orthopaedic Clinic

Using a reverse engineering capability to quantify the factors that control the rigid body mechanics of the wrist, a mathematical forward animation capability and model of wrist motion that allows the carpus to move under its own rules is being developed. This characterises the isometric connections, from which was developed the Stable Central Column Theory of Carpal Mechanics - which incorporates the Law of Rules Based Motion.This work has now advanced to the ability to reapply the extracted rules to allow rules-based rigid body reanimation of an individual wrist. As each wrist is unique, there is a given reality that each reanimation must be based on an individual wrist's unique rules, and the aspiration to create a standard or normal wrist is unrealistic.Using True Life Anatomy (Adelaide, Aust) analysis software, the specific rules (morphology / connectivity / interaction / loading) of individual wrists have been characterised, and then reapplied in a rigid body reanimation environment using Adams (MSC Software, U.S.) software.In the preliminary application of this biomechanics environment, by using the reverse engineering / forward reanimation process, wrist motion can be recreated - based purely on the unique rules, extracted from individual wrists. Instability of the proximal scaphoid was evident in several of the animations, and there was confirmation that the spatial attachment points of the isometric constraints are very exacting. The actual attachment and specific morphology of the carpal bones varied between individual wrists.Using a reverse engineering and then forward reanimation process, we have been able to recreate wrist motion using the rigid body mechanics based on the Law of Rules Based Motion. Further work is required, but the potential to apply “what if” virtual surgery options to an individual injured wrist and more precisely characterise and test solutions to wrist dysfunction are becoming realised.

Gluteal tendons tears are increasingly being recognised as a cause of recalcitrant trochanteric pain, but there is a paucity of robust studies analysing the type of tears, results and predictors of outcome. Patients with gluteal tendon tears resistant to conservative treatment who underwent isolated open repair (IR) or total hip arthroplasty and concomitant repair (THA+repair) with a minimum 1-year follow-up were retrospectively assessed separately. Type of tear, surgical approach, and fixation methods were registered. Complications and postoperative outcomes were analysed: visual analogue scale (VAS) of pain, VAS satisfaction, and activity level. Univariate regressions and multivariable models were developed. 90 cases were included: 62 cases underwent IR and 28 cases THA+repair, with an average follow-up of 3.9 years and 2.6 years, respectively. 13 complications were found (n = 5 IR, n = 8 THA+repair), including 9 re-operations (n = 4 IR, n = 5 THA+repair). Mean VAS pain score was 3.02 (SD 2.74) for the IR and 2.32 (SD 2.43) for THA+repair group. Mean VAS satisfaction was 7.09 (SD 3.07) and 7.68 (SD 2.71) for the IR and THA+repair group, respectively. In the IR group 61.4% returned to all pre-injury activities, whereas in the THA+repair group 79% did. Full-thickness tears had higher VAS pain scores (p = 0.0175), and there was trend (p > 0.05) towards higher complications, re-tears and lower VAS satisfaction in this type of tears in both groups. No statistically significant differences were found in outcomes when comparing THA+repair through direct anterior (DAA) with lateral approach (LA). Isolated gluteal tendon repair or THA+repairs seem to be safe procedures with high levels of satisfaction at short- to mid-term follow-up. The presence of a full-thickness tear is a predictor of inferior outcomes.

BackgroundPeriprosthetic joint infection (PJI) is a devastating condition and there is a lack of evidence to guide its management. We hypothesized that treatment success is independently associated with modifiable variables in surgical and antibiotic management.MethodsThe is a prospective, observational study at 27 hospitals across Australia and New Zealand. Newly diagnosed large joint PJIs were eligible. Data were collected at baseline and at 3, 12, and 24 months. The main outcome measures at 24 months were clinical cure (defined as all of the following: alive, absence of clinical or microbiological evidence of infection, and not requiring ongoing antibiotic therapy) and treatment success (clinical cure plus index prosthesis still in place).ResultsTwenty-four-month outcome data were available for 653 patients. Overall, 449 patients (69%) experienced clinical cure and 350 (54%) had treatment success. The most common treatment strategy was debridement and implant retention (DAIR), with success rates highest in early postimplant infections (119 of 160, 74%) and lower in late acute (132 of 267, 49%) and chronic (63 of 142, 44%) infections. Selected comorbidities, knee joint, and Staphylococcus aureus infections were independently associated with treatment failure, but antibiotic choice and duration (including rifampicin use) and extent of debridement were not.ConclusionsTreatment success in PJI is associated with (1) selecting the appropriate treatment strategy and (2) nonmodifiable patient and infection factors. Interdisciplinary decision making that matches an individual patient to an appropriate management strategy is a critical step for PJI management. Randomized controlled trials are needed to determine the role of rifampicin in patients managed with DAIR and the optimal surgical strategy for late-acute PJI.

Complete rupture of the conjoint pes anserinus tendon is rare, and isolated rupture without injury to associated structures has not been previously reported in the literature. A case of complete isolated rupture of the pes anserinus tendon is described in a young, healthy male. The non-specific nature of the presentation and rarity of the condition makes diagnosis from history and examination alone challenging. Magnetic resonance imaging was critical in making the correct diagnosis and excluding other potential-associated injuries with the diagnosis confirmed intraoperatively. The patient underwent surgical repair and rehabilitation and made significant progress. The diagnosis may be overlooked on a routine knee MRI, particularly in the absence of other associated injuries. An untreated injury may result in a poor outcome for the patient, with chronic pain and reduced function. Hence it is important to consider it in traumatic injuries to the region, with a view for an extended scan to visualise the full extent of the pes tendons to their insertion, particularly when there is high fluid signal in the popliteal fossa along the semitendinosus.

Breakage of the femoral stem component of a total hip replacement is now uncommon but continues to be seen with certain stem designs and in certain patient groups. Data previously published on this topic has been limited, either gathered from a single surgeon or centre, or included only a single stem design. We reviewed the data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), identified and analysed 143 stem breakages over a period of 16 years, covering 44 different stem designs. Our data confirms previously published findings that risk factors for stem breakage include patient age at implantation of under 70, male gender, as well as the use of exchangeable necks. We found no association with initial diagnosis, or type of acetabular component implanted. We did however also find, excluding exchangeable neck designs, that after 4.5 years a cemented stem had a significantly higher risk of breakage then a cementless stem. To our knowledge this is the 1st paper to suggest cemented fixation as a specific risk factor for stem breakage. The analysis of rare complications such as stem breakage is only possible through large data collection systems such as the AOANJRR. Whilst there have been recent advances in materials and manufacturing techniques, we recommend that surgeons are aware of all the specific risks when considering implant choices for individual patients.

For transgender women, genital adjustment surgery involves removal of the natal reproductive organs and creation of a neovagina, vulva and clitoris. We conducted a review of the medical literature in order to summarise the issues that can affect the health of the neovagina in the long term, and to make recommendations on how to manage these issues.

A clear surgical field is critical during endoscopic sinus surgery (ESS). Hypotensive anesthesia and cardiac output (CO) may optimize the surgical field; however, evidence of their effect on bleeding and cerebral blood flow is conflicting. The aim of this study was to evaluate the effect of blood pressure (BP) and CO on intraoperative bleeding and middle cerebral artery blood flow velocity (Vmca ) during ESS. This was a prospective randomized controlled trial. Patients undergoing ESS for chronic rhinosinusitis at a tertiary institution in 2013 were randomized to receive BP manipulation using target-controlled noradrenaline infusion during surgery to either their left or right sinuses. The contralateral side in each patient served as control. Bleeding was scored using a 0 to 10 point bleeding assessment scale (BAS, 0-10) and Vmca was measured using transcranial Doppler ultrasonography every 10 minutes or when surgically opportune, and time-matched with BP and CO. Data was analyzed using Bland-Altman methods. A total of 105 time points were collected across a mean arterial pressure (MAP) range of 32 to 118 mmHg. Significant correlations were demonstrated between MAP and Vmca (r = 0.7, p < 0.0001), MAP and BAS (r = 0.50, p < 0.0001), CO and Vmca (r = 0.57, p < 0.0001), and CO and BAS (r = 0.42, p < 0.0001). The best surgical fields were seen at 40 to 59 mmHg MAP. However, MAP below 60 mmHg produced >50% reduction in Vmca in more than 10% of time points. Balancing surgical visibility with organ perfusion remains a challenge. The results of this study show that moderate hypotension significantly improves the surgical field; however reducing BP below 60 mmHg may risk cerebral hypoperfusion.