Aims

This study aims to determine difference in annual rate of early-onset (≤ 90 days) deep surgical site infection (SSI) following primary total knee arthroplasty (TKA) for osteoarthritis, and to identify risk factors that may be associated with infection.

The aim of this study was to determine the incidence, annual trend, perioperative outcomes, and identify risk factors of early-onset (≤ 90 days) deep surgical site infection (SSI) following primary total knee arthroplasty (TKA) for osteoarthritis. Risk factors for early-onset deep SSI were assessed.

We performed a retrospective population-based cohort study using prospectively collected patient-level data from several provincial administrative data repositories between January 2013, and March 2020. The diagnosis of early-onset deep SSI was based on published Centre for Disease Control/National Healthcare Safety Network (CDC/NHSN) definitions. The Mann-Kendall Trend Test was used to detect monotonic trends in early-onset deep SSI rates over time. The effects of various patient and surgical risk factors for early-onset deep SSI were analyzed using multiple logistic regression. Secondary outcomes were 90-day mortality and 90-day readmission.

A total of 20,580 patients underwent primary TKA for osteoarthritis. Forty patients had a confirmed deep SSI within 90-days of surgery representing a cumulative incidence of 0.19%. The annual infection rate did not change over the 7-year study period (p = 0.879). Risk factors associated with early-onset deep SSI included blood transfusions (OR, 3.93 [95% CI 1.34-9.20]; p=0.004), drug or alcohol abuse (OR, 4.91 [95% CI 1.85-10.93]; p<0.001), and surgeon volume less than 30 TKA per year (OR, 4.45 [1.07-12.43]; p=0.013). Early-onset deep SSI was not associated with 90-days mortality (OR, 11.68 [0.09-90-58]; p=0.217), but was associated with an increased chance of 90-day readmission (OR, 50.78 [26.47-102.02]; p<0.001).

This study establishes a reliable baseline infection rate for early-onset deep SSI after TKA for osteoarthritis through the use of a robust methodological process. Several risk factors for early-onset deep SSI are potentially modifiable or can be optimized prior to surgery and be effective in reducing the incidence of early-onset SSI. This could guide the formulation of provincial screening programs and identify patients at high risk for SSI.

Dual plate constructs have become an increasingly common fixation technique for midshaft clavicle fractures and typically involve the use of mini-fragment plates. The goal of this technique is to reduce plate prominence and implant irritation, as these are common reasons for revision surgery. However, limited biomechanical data exist for these lower-profile constructs. The study aim was to compare dual mini-fragment orthogonal plating to traditional small-fragment clavicle plates for biomechanical non-inferiority and to determine if an optimal plate configuration could be identified, using a cadaveric model.

Twenty-four cadaveric clavicles were randomized to one of six groups (n=4 per group), stratified by CT-based bone mineral content (BMC). The six different plating configurations compared were: pre-contoured superior or anterior fixation using a single 3.5-mm LC-DC plate, and four different dual-plating constructs utilizing 2.4-mm and 2.7-mm reconstruction or LC-DC plates. The clavicles were plated and then osteotomized to create an inferior butterfly fracture, which was then fixed with a single interfragmentary screw (OTA 15.2B). Axial, torsional, and bending (anterior and superior surface loading) stiffness were determined for each construct through non-destructive cyclic testing, using an MTS 858 Bionix materials testing system. This was followed by a load-to-failure test in three-point superior-surface bending. Kruskal-Wallace H and Mann-Whitney U were used to test for statistical significance.

There were no significant differences in BMC (median 7.9 g, range 4.2-13.8 g) for the six groups (p=1.000). For axial stiffness, the two dual-plate constructs with a superior 2.4-mm and anterior 2.7-mm plate (either reconstruction or LC-DC) were significantly stiffer than the other four constructs (p=0.021). For both superior and anterior bending, the superior 2.4-mm and anterior 2.7-mm plate constructs were significantly stiffer when compared to the 3.5-mm superior plate (p=0.043). In addition, a 3.5-mm plate placed anterior was a stiffer construct than a superior 3.5-mm plate (p=0.043). No significant differences were found in torsional stiffness or load-to-failure between the different constructs.

Dual plating using mini-fragment plates is biomechanically superior for fixation of midshaft clavicle fractures when compared to a single superior 3.5-mm plate and has similar biomechanical properties to a 3.5-mm plate placed anteriorly. With the exception of axial stiffness, no significant differences were found when different dual plating constructs were compared to each other. However, placing a 2.4-mm plate superiorly in combination with a 2.7-mm plate anteriorly might be the optimal construct, given the biomechanical superiority over the 3.5-mm plate placed superior.

Background

One of the prime concerns when managing patients in plaster casts is loss of reduction. There have been studies showing that proper moulding of the plaster cast is critical in maintaining reduction. Recent studies have negated concerns that fibreglass (FG) casts do not allow swelling, when compared to plaster of Paris (POP) casts. However, their potential in maintenance of reduction has not been investigated.

BACKGROUND: One of the prime concerns when managing patients in plaster casts is loss of reduction. There have been studies showing that proper moulding of plaster cast is critical in maintaining reduction. Recent studies have negated concerns that fibreglass (FG) casts do not allow swelling, when compared to plaster of Paris (POP) casts. However, their potential in maintenance of reduction has not been investigated.

MATERIALS AND METHODS: We compared the three-point bending properties of FG casts with POP casts over the first 48 hours. The effect of splitting the casts, at one hour and 24 hours, was studied. Also, the tolerance to handling was assessed by moving the hinge joint while the casts were setting.

Three identical jigs with hinged metal rods were designed to simulate Colle’s fracture. The bending force was provided by 0.5 kg weight applied at one end of the jig. The resultant displacement was measured to nearest 0.01 mm over the next 48 hours. Each test was repeated 6 times (total 8 groups and 42 tests).

RESULTS: Most deformation occurred within 1 hour for FG casts and 24 hours for POP casts. The total deformation in FG cast (mean 3.4 mm) was significantly less than in POP casts (mean 6.2 mm) (p > 0.05).

Splitting at 1 hour increased the final deformation of the POP cast and not of the FG cast (p > 0.05). No significant difference was noticed if the casts were split at 24 hours.

CONCLUSION: Three-point moulding with FG casts can provide better constant loading at the fracture site than the POP casts. Early setting of FG cast allows earlier splitting. We recommend clinical trials to ascertain the safety and efficacy of split FG casts.

Introduction: The mini C arm is a surgeon operated fluoroscopic device for use in the operating theatre for extremity orthopaedic surgery. There have been no studies comparing the radiation dose of the mini C arm and the conventional C arm.

The aim of this study was to determine if the exposure to patient and surgeon was decreased with use of the mini C arm.

Methods: This was a case-control study. Operations performed with the mini C arm were matched for type, complexity and operator with cases performed with the conventional C arm. The number of exposures and the total time of exposure were measured, and the skin dose and scatter calculated.

Results: There were 16 case-control pairs. There was a significantly greater number of exposures taken by the surgeon operated mini C arm (p=0.02), but there was still a significantly lower exposure to the surgeon with the mini C arm (p=0.004). There was no significant difference in the patient skin dose (p=0.21).

Conclusions: The surgeon operated mini C arm results in a greater exposure time and number of exposures. Despite this, the mini C arm exposes the surgeon to less radiation compared to the conventional C arm in extremity orthopaedics. The radiation exposure with the mini C arm is approximately half that of the conventional C arm. The increased number of exposures may occur because surgeons are more trigger happy with the mini C arm, or because there are technical problems with achieving a useful image. The mini C arm should be used for extremity orthopaedics whenever possible to decrease the radiation exposure.

Background: The Mini C-arm has been heralded as a safer means of fluoroscopy. No clinical data on the use of mini C-arm is available in the literature.

Aim: The purpose of this study was to compare the exposure in clinical practice from the conventional C-arm and the Mini C-arm and scrutinize patterns of exposure.

Materials/methods: Case-Control design. All operations using the mini C-arm were reviewed. Control cases were identical operations using the conventional C-arm. The Sign test was used to detect the number of exposures taken and the dose of radiation.

Results: There were 16 operations with valid case-control pairs. The number of exposures performed was significantly greater for the mini C-arm (p=0.05), but the emitted dose of radiation was significantly smaller (p< 0.001) for the mini C-arm.

Conclusions: The mini C-arm is a safer device for extremity surgery, but the surgeon should be careful to avoid excessive exposures.

Introduction. Acute distal biceps rupture can be a devastating injury and surgical repair offers the only real chance of full recovery. We report on a new surgical technique in which the use of suture anchors and a modified de-tensioning suture was employed to protect the repair in the early post operative recovery period and aid early rehabilitation and return to full pre-injury activity.

Materials & Methods. Using the standard anterior incision the distal biceps tendon was approximated to the radial tuberosity using two Mitek sutures and a sliding stitch. Using 2-0 Vicryl, de-tensioning sutures were used to attach the medial and lateral sides of the tendon to the underlying brachialis muscle. Post-operative recovery encouraged isometric contractions as early as 24 hours and after 2 weeks allowed flexion and extension with gravity eliminated. Six weeks onwards full active movement commenced with gradual increase in stretching and strengthening exercise.

Results. 14 patients underwent this procedure and all returned to pre-injury activity levels within 9 months. Follow up (6–14 months) demonstrated all had regained pre-injury levels of strength in flexion and supination.

Discussion. Using two suture anchors, it is suggested that load bearing strength is greater than the trans-osseous method, providing even tension is applied to both anchors. This can be achieved using a sliding stitch. De-tensioning sutures restore the isometric pull on biceps in the early phase and protects the repair.

Conclusion. All cases operated on in this way have made excellent recoveries and have returned to full pre-injury levels of activity. We therefore recommend this technique as a way of enhancing rehabilitation in what can be a devastating injury for the active sporting individual