Extensor Pollicis Longus (EPL) rupture occurs in 0.2 – 3% of fractures of the distal radius. The underlying mechanism is unknown. This study prospectively evaluates EPL and surrounding structures using high-resolution ultrasound (US) in patients with distal radius fracture 6 weeks after injury and correlates the findings with initial radiographic measurements.

US can assess tendon size, echogenicity and peak velocity, haematoma depth and thickness of the extensor retinaculum and tendon sheath. The normal wrist was examined as a control.

Results: 58 patients with mean age 54 yrs (39 female, 19 male), 28/58 underwent manipulation in the Emergency Department and 11/58 went to the Operating Theatre for fixation.

Radiographic measurements – AO classification: A-32, B-12 and C-14. 76% were undisplaced fractures with dorsal tilt less than 10.

Statistical analysis revealed that EPL tendon peak velocity is significantly slower on the fractured side (p=0.001). The extensor retinaculum thickness is greater (p=0.003) and the synovial sheath thickness is greater (p less than 0.001) on the fractured side. Synovial sheath thickness was also found to be significantly greater in the intra-articular fractures (p=0.03) and the undisplaced fractures (p=0.03).

Conclusions: This study correlates patterns of distal radius fracture that are associated with US changes in EPL tendon.

As expected, the peak tendon velocity is reduced following fracture, but this is still significant at 6 weeks. This could be associated with impaired diffusion of nutrients within the synovial sheath.

There is also persistent soft tissue swelling with significantly increased extensor retinaculum and synovial sheath thickness. This is a protective response to trauma, but we propose that this could interfere with the already tenuous blood supply of the EPL tendon. It could also reduce diffusion of nutrients within the tendon sheath, particularly in undisplaced fractures, where the extensor retinaculum is not torn and any increased pressure may not be dispersed.

The study is ongoing with the aim to be able to identify patients at risk for EPL rupture and potentially be able to prevent it by early surgical decompression.

Introduction: Long term performance of total knee replacements is governed by wear of ultra-high molecular weight polyethylene (UHMWPE) which leads to aseptic loosening of the implant. Little has been done to reduce wear due to the femoral component properties in knee joint replacement. Scratching of the femoral component has been identified in retrieved knee replacements. Using a material that has a higher scratch resistance than current metals may reduce the rate of UHMWPE wear in knee replacements. In this study we investigated the effects of using an oxidized Zirconium femoral component has on wear in knee replacements.

Methods: Total knee replacements made of CoCr and oxidised zirconium were tested in a four station, six degrees of motion knee simulator for 4 million cycles. The surface roughness values (Ra, Rz and Sm) for the metal counterfaces was measured through the test. In addition gravimetric wear of the UHMWPE inserts was recorded. Scanning electron microscopy of the two counterface surfaces was performed to provide information on possible mechanisms involved in the wear process.

Results: The starting surface roughness for both CoCr and oxidised zirconium were similar (Ra=0.03m). Oxidised zirconium was significantly more scratch resistant than CoCr; Ra (mean average roughness) of 0.7m compared to 0.43m (p< < 0.01) at end of test, with similar differences in the other surface roughness parameters. This was accompanied by a 4 fold reduction in wear of UHMWPE 49.60mg to 12.48mg (p=0.02).

SEM analysis of the surfaces of the metals revealed large deep scratches of the CoCr implants which were aligned in the A-P sliding direction. Barium sulphate particles were seen embedded in the surface of the femoral component. Voids were seen in the surface of the cobalt chrome and particles of silicate polishing powder were seen in these voids. There was also evidence of scratches originating at these voids. By contrast oxidised zirconium, showed small amounts of superficial scratching with an intact surface and no evidence of third body particles.

Summary and conclusions: Oxidised zirconium leads to a reduction in wear of UHMWPE due to its increased resistance to third body wear. It has the potential to increase the longevity of total knee replacements by reducing wear of UHMWPE. Additionally, polishing powder used in the manufacture of cobalt chrome femoral components of knee joint replacements is a potential source of third body particles.

Introduction and Aims: While successful long-term results have been shown for ligament reconstruction–tendon interposition arthroplasty for treatment of thumb basal joint osteoarthritis, the need for invasive ligament reconstruction has not been established. In this study we describe long-term results utilising the technique of tendon interposition arthroplasty with dynamic tendon transfer and capsulorrhaphy.

Method: Twenty-four thumbs (21 patients) were evaluated at an average of 7.1 years (1.8–19.5 years) post-procedure. Capsulorrhaphy was performed utilising APL tendon slips where tissue was insufficient. The APB origin was advanced via tendon transfer (FCR to APB), providing a stabilising abductor moment. Subjective assessment was performed using Visual Analogue Scores (VAS), Disabilities of Arm, Shoulder, Hand (DASH) scores, and patient satisfaction scales. Objective assessment included post-operative range of motion (ROM), grip/pinch strength, and radiographs for interposition arthroplasty height.

Results: Twenty of 21 patients (95%) were satisfied and described results as either good or excellent. Twenty of 21 patients (95%) would undergo surgery again. Mean VAS was 8.7 at rest and 10.2 with activity (0, no pain; 100, maximum pain). Mean DASH score was 16.9 (range from 0, no difficulty performing daily tasks to 100, unable to perform daily tasks). ROM, grip, lateral and tip pinch strengths were comparable with those of the contralateral thumb. AP radiographs showed preservation in 12 of 12 patients (100%). Fourteen of 21 patients received the procedure on their dominant hand.

Conclusion: Treatment of basal joint osteoarthritis with our technique provided stable and functional reconstructions, resulting in excellent pain relief. Results were comparable to, or better than, those previously cited in the literature for alternative procedures. These results suggest that dogma requiring static ligament reconstruction or suspension may need to be re-evaluated.

Introduction and Aims: The volar carpal ganglion (VCG) is a common benign tumor of the hand complicated by multiple recurrences with conventional treatment. Despite being a common condition, we know of no report describing post-operative functional outcome. We evaluated functional outcome, pain, scarring, and recurrence after VCG excision in the last 15 years.

Method: Twenty-eight patients were considered for inclusion in this study. All patients had been surgically treated for volar carpal ganglia in the last 15 years. Of these, 16 were available for follow-up after exclusion of patients who had since deceased, moved, or were otherwise lost to follow-up. Mean follow-up period was 55 months (nine–135 months). Functional outcome of the upper extremity was evaluated using the standard DASH questionnaire. DASH scores can range from zero (no difficulty in performing daily tasks) to 100 (unable to perform daily tasks). Pain, scarring, and recurrence were also assessed.

Results: Sixteen patients who underwent surgical excision of their recurrent volar carpal ganglions were available for follow-up at the time of the study. They included six men and 10 women, with a mean age of 47 (range 11–70 years). The duration of symptoms prior to excision ranged from two to 50 months. Pain was the main reason for surgery while one patient reported that surgery was performed for cosmetic reasons. There were eight patients in the nine-month to three-year follow-up period and the average DASH score was 7.6. The four patients in the three to five-year follow-up period had an average DASH of 8.1. The four patients in the five plus years of follow-up had an average DASH of 1.7. The improvement in functional outcome correlated with time since surgery, however these differences were not statistically significant. Two of the 16 patients had recurrences within six months after excision. Increased pain was reported in these patients only. No patients complained of significant scarring post-operatively.

Conclusion: Multiple treatment modalities including aspiration and surgery are discussed in the literature with great outcome variability. Our series is the first long-term functional assessment after VCG excision. Thus, surgery is an option for treatment of this common condition as evidenced by low recurrence and DASH scores and high patient satisfaction.

Purpose: Using the finite element analysis, the authors analyze the effect of the articulating material properties of the total hip arthroplasty to stress and micro-motion of the proximal femur and the femoral stem.

Material and methods: The head (28mm) and the acetabular component (outer diameter = 54mm, liner thickness = 11.4mm) were considered as ceramic on ceramic, cramic on polyethylene, metal on metal, metal on polyethylene and metal on metal-polyethylene. The femur was modeled with different friction coefficients according to the different contact portion of the femoral stem, which was modeled after Omni fit HA #9(Osteonics, Allendale, NJ). Non-linear contact analysis was proceeded in human with body weight 70Kg at one leg standing and stair climbing.

Result: The maximal yield strength was always higher in hard-hard coupling. In one leg standing, the site of maximal yield strength was represented at the contact point of articulation. In stair climbing, the site of maximal yield strength was represented at the same site in hand on hard coupling but at the lateral aspect of the neck in hard-soft couplings. There were no changes in the patterns of stress distribution but the micro-motions were up to the limit of bone in growth in hard-hard coouplings.

Conclusion: The maximal yield strength and the micro-motions revealed different values according to the articulating materials. These findings were considered valuable information to postoperative management and longavity of the total hip prosthesis but requiring the following experimental and clinical study.

Introduction: Shortening of the affected limb has frequently been observed in children with Legg-Calvé-Perthes disease (LCPD). Many factors have been thought as the cause of this residual shortening after LCPD. There has been no clear answer regarding which is more responsible for the residual shortening between coxa plana and the disturbed physeal growth. To clarify the main cause of residual shortening, clinical and experimental studies were conducted.

Materials and Methods: For clinical study, 40 LCPD children with definite shortening were evaluated. This included 20 children with active disease and 20 children at skeletal maturity. Teleoroentgenograms were obtained for all children. For the experimental study, LCPD simulation in 30 piglets was achieved by disrupting the blood supply to the capital femoral epiphysis.

Results: In the clinical study, total shortening in the skeletal maturity group was 14.6 mm, which consisted of 3.2 mm (16%) shortening by decreased epiphyseal height and 11.5 mm (84%) shortening by physeal growth disturbance. Total shortening in the active disease group was 7.9 mm, which consisted of 6.4 mm (84%) decrease of epiphyseal height and 1.5 mm (16%) shortening by physeal growth disturbance. In the experimental study, overall shortening (13.6 mm) in the piglet model showed a predominance of disturbed physeal growth. The proportions were 3.2 mm (24%) by epiphyseal height decrease and 10.4 mm (76%) by physeal growth disturbance.

Conclusion: Physeal growth disturbance was mostly responsible for the residual shortening following LCPD. However, in the stages of active disease, the shortening of the extremity was mainly caused by a decrease of epiphyseal height.

In clinical studies of cemented total hip arthroplasty (THA), polished stems produce less slippage at the bone-cement interface than roughened stems. Our objective is to assess the effect of stem-cement debonding on the bone-cement interface shear behaviour of hip implants using simplified axisymmetric stem-cement-aluminum models.

We emulated the femoral stems using stainless steel tapered plugs with either a rough (i.e. bonded) or smooth (i.e. unbonded) surface finish. Three different taper angles (5°, 7.5°, 10°) were used for the unbonded constructs. Non-tapered and tapered (7.5°) aluminum shells were used to emulate the diaphyseal and metaphyseal segments of the femur. In all cases, the cement-aluminum interface was designed to have the same shear strength as has been reported for bone-cement interfaces (~8 MPa). The test involved applying axial compressive loading at a rate of 0.02 mm/s until failure. Six specimens were tested for each combination of the parameters.

The unbonded stems sustained about twice as much load as the bonded stem, regardless of taper angle, and the metaphyseal model carried 35-50% greater loads than the diaphyseal models before shear failure or slippage. The unbonded constructs reached peak load with excessive displacement due to creep of the cement mantle while the bonded constructs failed in shear at the cement-aluminum interface. This result supports the hypothesis that the wedging forces created in the unbonded construct increase the compression forces across the aluminum-cement interface, thereby increasing its shear resistance. A finite element analysis predicted that the cement could withstand the hoop stress under these loading circumstances and this prediction was confirmed by visual inspection of the cement after each test.

Our results suggest that smooth or unbonded stems should sustain less slippage and shear damage at the bone-cement interface than roughened or bonded stems due to the wedge-induced compressive stress; this increased load capacity will be particularly valuable when the condition of the bone-cement interface is suboptimal.

Purpose: To introduce modified tibial inlay technique for autogenous bone-patellar tendon-bone (BPTB) posterior cruciate ligament (PCL) reconstruction and evaluate the outcomes of PCL reconstruction by this method.

Methods: Fifty patients who underwent autogenous BPTB PCL reconstruction using modified tibial inlay technique were evaluated at average 30.9 months (range 12–52).

The outcomes were assessed by stress radiographs, maximal manual test with KT-2000 arthrometer, IKDC grading and OAK knee score.

Results: Average side to side difference in push view with Telos stress device decreased from 11.7mm to 3.2mm. Difference in maximal manual test with KT-2000 arthrometer also decreased from 11.5mm to 3.1mm. Final IKDC grading was A in six patients, B in thirty four, C in nine and D in one.

Average OAK score improved from 64.3 to 86.4

Conclusion: We consider that the modified tibial inlay technique is a method to reduce technical effort and contribute to satisfactory clinical results in autogenous BPTB PCL reconstruction.