Background

Alignment and soft tissue (ligament) balance are two variables that are under the control of a surgeon during replacement arthroplasty of the knee. Mobile bearing medial unicompartmental knee replacements have traditionally advocated sizing the prosthesis based on soft tissue balance while accepting the natural alignment of the knee, while fixed bearing prosthesis have tended to correct alignment to a pre planned value, while meticulously avoiding overcorrection. The dynamic loading parameters like peak adduction moment (PKAM) and angular adduction Impulse (Add Imp) have been studied extensively as proxies for medial compartment loading. In this investigation we tried to answer the question whether correcting static alignment, which is the only alignment variable under the control of the surgeon actually translates into improvement in dynamic loading during gait. We investigated the effect of correction of static alignment parameter Hip Knee Ankle (HKA) angle and dynamic alignment parameter in coronal plane, Mean Adduction angle (MAA) on 1st Peak Knee Adduction Moment (PKAM) and Angular Adduction Impulse (Add Imp) following medial unicompartmental knee replacements.

Clinical and radiological assessment of results of vertebral body stenting procedure.

Introduction: Use of metallic stents along with cement have shown good restoration of the vertebral body in cadaveric spines. We have presented the early results of vertebral body stenting done at Royal Derby Hospitals.

Patients and Methods: All patients had a transpedicular approach to the vertebral body. The vertebral body stent was expanded using a balloon as in balloon kyphoplasty. The balloon was removed leaving the stent in place. The resultant cavity was filled with partially cured polymethyl methacrylate in osteoporotic fractures and calcium phosphate cement in traumatic fractures.

Radiological assessment included pre operative measurement of vertebral body angle, correction achieved and maintenance of correction at follow up

All patients were assessed using the visual analogue score and oswestry disability index.

The procedure was done in 14 fractures (10 patients). 9 fractures were traumatic while 5 were osteoporotic fractures. The mean age of the traumatic fractures was 54.28 years while the mean age of osteoporotic fractures was 82.34 years. Mean follow up was 10 months. All traumatic fractures were type A 3.1. Mean vertebral body angle correction achieved was 8.3° (4° to 14.2°). None of the patients lost the reduction at follow up.

The mean VAS for pain at 6 months was 3.8. The mean oswestry disability index was 22% for traumatic fractures, while it was 44% for osteoporotic fractures.

Vertebral body stenting is a safe procedure. It was successful in restoring the anterior column with encouraging radiological and clinical results.

Tension band wire fixation continues to be the most popular method of fixation for displaced olecranon fractures despite several biomechanical studies questioning the validity of the tension band concept. Our aim was to compare the outcome of the tension band wire (TBW) method with plate fixation. 58 consecutive olecranon fractures underwent internal fixation in 58 patients between September 2000 and December 2004. There were 30 male and 28 female with a mean age at the time of surgery of 52.5 years for the TBW group (range 19 to 88) and 46.1 for the plate group (range 19 to 72). Patients were excluded if they were less than 16 years of age. Choice of fixation was based on surgeon preference, fracture pattern and presence of associated injuries. 43 patients were managed with the AO tension band technique and 15 with plate fixation. Clinical assessment and functional analysis was performed using Helm’s scoring system. Radiographic assessment was performed to assess the quality of reduction. All fractures were displaced and classified according to Colton’s classification. Mean follow up was 13 months (range 6 to 18) and similar for the two groups. For the TBW group 41 (95 %) had a fair or good result. 27 (62.8%) patients had symptomatic metal prominence requiring implant removal. In the plate fixation group 14 (94%) had a fair or good functional result despite having more complex fractures. Only 2 (18%) patients required implant removal for symptomatic metalwork, including one failure due to a technical problem. Similar functional results were seen with plating and tension band wiring of displaced olecranon fractures. Despite meticulous technique, tension band wire fixation still has an unacceptably high complication rate with symptomatic metal prominence requiring further surgery. To avoid this problem, we recommend plating, even for the more simple olecranon fractures.

Background: Tension Band wiring technique is commonly used to treat transverse patella fractures. The commonly used configuration has parallel K wires and a stainless steel wire loop oriented as a figure of 8. Use of non-metallic suture materials as reliable fixation materials have been reported. We investigated the properties of composite polyester suture (Fibre wire) when used in Tension band wiring of patella.

Methods: A wooden model of a transversely fractured patella was used. The fracture was fixed using two K wires and a loop of horizontally oriented stainless steel wire or fibre wire. Two wire twists placed at corners were used for SS wire loops. For fibre wire samples a tensioning device was used and the knots placed at one corner. Interfragmentary compression at the point of wire breakage and fracture displacement on physiologic cyclic loading was measured for each fixation construct. The reliability of tensioning device (Arthrex) and the effect of using multiple strands of wire were assessed.

Results: Use of the tensioning device produced interfragmentary compression that could be repeated reliably. The addition of a further strand increased the interfragmentary compression developed by 94%. There was no significant difference between interfragmentary compression developed between groups (p> 0.05). The average interfragmentary compression produced for three repetitions for the individual groups, Fibre wire (1394N), SS wire of 1.0mm diameter (1320N), SS Wire of 1.25mm diameter (1594N) were comparable. This increased significantly when a second loop of fibre wire was used (2566N). Permanent fracture displacement at physiologic loads were, Fibre wire (9.7mm, SD 2.7mm), SS wire of 1.0mm diameter (7.0mm, SD 1.0mm) and SS Wire of 1.25mm diameter (7.4mm, SD 2.3mm). The addition of the second strand of fibre wire decreased the displacement significantly (4.8mm, SD 0.6mm). The effect of second strand of fibre wire decreased the displacement by 97% while the decrease on addition of the second strand of stainless steel wire was only 14%.

Discussion: Interfragmentary compression produced to failure was comparable between a single strand of fibre wire, 1.0mm SS wire and 1.25mm SS wire, the commonly used SS wire diameters in fixation of fractured patella. The standard deviations of final permanent displacement were higher with the larger diameter of SS wire, indicating that the use of a thicker wire would require some preloading before it is uniformly tensioned. Amongst the SS wire diameters tested, 1.0mm resulted in least variations (SD 1.0mm).

The addition of second strand resulted in a marked improvement in displacement with Fibre wire and variations between different samples were smaller than in any other group tested (SD 0.6mm)

Conclusions:

Fibre wire has similar strength to failure when compared the commonly used thickness of stainless steel wire for fixation of patella.

Assesment at teaching courses has been restricted to subjective assessment by questionnaire of the quality of teaching sessions and the teachers. This does not give any information on the extent of learning by the participants. Formal skills assessment during a practical course can be complex, time consuming and may distract from the teaching process. The purpose of the study was to quantify learning at a skills course on open shoulder surgery using a knowledge based questionnaire before and after completion of the course.

Method: 22 participants at a two day shoulder surgical workshop completed a knowledge questionnaire before (entry assessment) and immediately after completion (exit assessment) of the course. Four participants were excluded because of incomplete forms. The questionnaire consisted of 10 multiple choice questions which represented the content of the programme. The questionaires were scored and the change in score calculated for each participant and expressed as a percentage of the initial score. An improvement in the score defined a positive learning experience.

Results: There was a positive learning experience for all participating surgeons. The average improvement was 17% {range 4–43%}. The pre course scores ranged from 43 to 92% {average 68.8%}, while the post course scores ranged from 67 to 100% {average 85.5%}. The improvement was dependent on the initial score, trainees with low initial scores registering the maximum percentage recorded increase in knowledge ie 23% (range 5–43%). We did not identify a relationship between grade of surgeon and learning as measured with this assessment.

Conclusions: Simple learning assessments can demonstrate and quantify learning experience at skills courses. The process is not time consuming and can be easily integrated into the structure of a course.