Non-invasive assessment of lower limb mechanical alignment and assessment of knee laxity using navigation technology is now possible during knee flexion owing to recent software developments. We report a comparison of this new technology with a validated commercially available invasive navigation system.

We tested cadaveric lower limbs (n=12) with a commercial invasive navigation system against the non-invasive system. Mechanical femorotibial angle (MFTA) was measured with no stress, then with 15Nm of varus and valgus moment. MFTA was recorded at 10° intervals from full knee extension to 90° flexion. The investigator was blinded to all MFTA measurements. Repeatability coefficient was calculated to reflect each system's level of precision, and agreement between the systems; 3° was chosen as the upper limit of precision and agreement when measuring MFTA in the clinical setting based on current literature.

Precision of the invasive system was superior and acceptable in all conditions of stress throughout flexion (repeatability coefficient <2°). Precision of the non-invasive system was acceptable from extension until 60° flexion (repeatability coefficient <3°), beyond which precision was unacceptable. Agreement between invasive and non-invasive systems was within 1.7° from extension to 50° flexion when measuring MFTA with no varus / valgus applied. When applying varus / valgus stress agreement between the systems was acceptable from full extension to 20° & 30° knee flexion respectively (repeatability coefficient <3°). Beyond this the systems did not demonstrate sufficient agreement.

These results indicate that the non-invasive system can provide reliable quantitative data on MFTA and laxity in the range relevant to knee examination.

Conventional computer navigation systems using bone fixation have been validated in measuring anteroposterior (AP) translation of the tibia. Recent developments in non-invasive skin-mounted systems may allow quantification of AP laxity in the out-patient setting.

We tested cadaveric lower limbs (n=12) with a commercial image free navigation system using passive trackers secured by bone screws. We then tested a non-invasive fabric-strap system. The lower limb was secured at 10° intervals from 0° to 60° knee flexion and 100N of force applied perpendicular to the tibial tuberosity using a secured dynamometer. Repeatability coefficient was calculated both to reflect precision within each system, and demonstrate agreement between the two systems at each flexion interval. An acceptable repeatability coefficient of ≤3 mm was set based on diagnostic criteria for ACL insufficiency when using other mechanical devices to measure AP tibial translation.

Precision within the individual invasive and non-invasive systems measuring AP translation of the tibia was acceptable throughout the range of flexion tested (repeatability coefficient ≤1.6 mm). Agreement between the two systems was acceptable when measuring AP laxity between full extension and 40° knee flexion (repeatability coefficient ≤2.1 mm). Beyond 40° of flexion, agreement between the systems was unacceptable (repeatability coefficient >3 mm).

These results indicate that from full knee extension to 40° flexion, non-invasive navigation-based quantification of AP tibial translation is as accurate as the standard invasive system, particularly in the clinically and functionally important range of 20° to 30° knee flexion. This could be useful in diagnosis and post-operative follow-up of ACL pathology.

Image-free navigation technology relies heavily on the surgeon carefully registering bony anatomical landmarks, a critical step in achieving accurate registration which affects the entire procedure. Currently this step may depend on placing a pointer superficially, with soft-tissue and skin obscuring these bony landmarks. We report initial results of using newly developed experimental software which automatically recognises the bone soft-tissue interface. This is the first critical step in development of automatic computer generation of the bone surface topography from ultrasound scanning.

Individual 2D ultrasound images (n=651) of the anterior femoral condyles and trochlear notch were used. Images were taken from 29 volunteers (20 male, 9 female). The software extracted bone-soft tissue interface by a two-step method based on a gradient evaluation and the elimination of false-positives with a graph closure. The trochlear notch was automatically defined by geometrical modelisation. Coordinates of both bone interface and trochlear notch position for each separate image were compared to a separate analysis performed manually by a single investigator. Error was calculated using root mean squared (RMS).

Median error (RMS) in locating bone soft-tissue interface was 0.67 mm, (mean 0.93 mm, SD 0.84 mm). Median error for trochlear notch topography was 1.01mm, (mean 1.41 mm, SD 1.37 mm).

Bone soft-tissue interface can be accurately defined and displayed by this software. Direct visualisation of critical bony landmarks could replace the current comparatively subjective placement of a pointer on superficial tissues. This has powerful application in both non-invasive and surgical computer-assisted acquisition of knee kinematics, and may have further applications in orthopaedic surgery.

Conventional computer navigation systems using bone fixation have been validated in measuring anteroposterior (AP) translation of the tibia. Recent developments in non-invasive skin-mounted systems may allow quantification of AP laxity in the out-patient setting.

We tested cadaveric lower limbs (n=12) with a commercial image free navigation system using passive trackers secured by bone screws. We then tested a non-invasive fabric-strap system. The lower limb was secured at 10° intervals from 0° to 60° knee flexion and 100N of force applied perpendicular to the tibial tuberosity using a secured dynamometer. Repeatability coefficient was calculated both to reflect precision within each system, and demonstrate agreement between the two systems at each flexion interval. An acceptable repeatability coefficient of ≤3mm was set based on diagnostic criteria for ACL insufficiency when using other mechanical devices to measure AP tibial translation.

Precision within the individual invasive and non-invasive systems measuring AP translation of the tibia was acceptable throughout the range of flexion tested (repeatability coefficient ≤1.6mm). Agreement between the two systems was acceptable when measuring AP laxity between full extension and 40° knee flexion (repeatability coefficient ≤2.1mm). Beyond 40° of flexion, agreement between the systems was unacceptable (repeatability coefficient >3mm).

These results indicate that from full knee extension to 40° flexion, non-invasive navigation-based quantification of AP tibial translation is as accurate as the standard invasive system, particularly in the clinically and functionally important range of 20° to 30° knee flexion. This could be useful in diagnosis and post-operative follow-up of ACL pathology.

Frail patients with neck of femur fracture, amongst other medical problems, are frequently fast-tracked to orthopaedic wards to meet government A&E waiting time targets.

This is a second cycle of audit since 2008 examining the safety of fast-tracking following individual critical incidents. Data was collected prospectively between March and June 2011 by the first on-call orthopaedic doctor.

56 patients (12 male), average age 81.2y (50–97) were fast tracked. 52 were correctly referred as intra/extracapsular fracture, however 4 did not have a neck of femur fracture. 9 patients were transferred with no verbal referral to the receiving orthopaedic doctor. On arrival to the ward, 8 patients were found to have abnormal observations and acute medical problems requiring immediate review from the physicians. There were a total of 150 omissions from a total of 456 points from the fast track protocol. Vital observations of patients fast-tracked after 2100h were worse (MEWS range 0 to 11) when compared with those fast-tracked prior to 2100h (MEWS range 0 to 3). This occurs at a time when medical staff support is minimal.

Fast-tracking is a common practice amongst many district-general and some teaching hospitals in Scotland. These data support concerns from orthopaedic surgeons highlighting a need for more complete initial assessment and management in A&E prior to transfer to the ward. Recent evidence suggests medical optimisation of the multiple acute and chronic medical comorbidities common amongst patients with neck of femur fracture is the main facilitator of early surgery which significantly reduces post-operative mortality.

Non-invasive assessment of lower limb mechanical alignment and assessment of knee laxity using navigation technology is now possible during knee flexion owing to recent software developments. We report a comparison of this new technology with a validated commercially available invasive navigation system.

We tested cadaveric lower limbs (n=12) with a commercial invasive navigation system against the non-invasive system. Mechanical femorotibial angle (MFTA) was measured with no stress, then with 15 Nm of varus and valgus moment. MFTA was recorded at 10° intervals from full knee extension to 90° flexion. The investigator was blinded to all MFTA measurements. Repeatability coefficient was calculated to reflect each system's level of precision, and agreement between the systems; 3° was chosen as the upper limit of precision and agreement when measuring MFTA in the clinical setting based on current literature.

Precision of the invasive system was superior and acceptable in all conditions of stress throughout flexion (repeatability coefficient <2°). Precision of the non-invasive system was acceptable from extension until 60° flexion (repeatability coefficient <3°), beyond which precision was unacceptable. Agreement between invasive and non-invasive systems was within 1.7° from extension to 50° flexion when measuring MFTA with no varus / valgus applied. When applying varus / valgus stress agreement between the systems was acceptable from full extension to 30° knee flexion (repeatability coefficient <3°). Beyond this the systems did not demonstrate sufficient agreement.

These results indicate that the non-invasive system can provide reliable quantitative data on MFTA and laxity in the range relevant to knee examination.

Intervention is rare following minimally displaced radial head fractures or positive elbow ‘fat pad’ signs. A pilot study (n=20) found no patient required active treatment after discharge following their first fracture clinic visit. We therefore initiated routine discharge from A&E with an advice sheet, and an ‘open-door policy’ if patients failed to progress.

51 patients were managed by A&E according to this protocol over a six-month period. A standardised assessment of symptoms, satisfaction and functional limitation was completed for 24 patients by phone; average time to follow-up 4.2 months (range 2–9 months). Fourteen (58.4%) reported no pain. The 10 patients (41.6%) with on-going pain reported a median visual analogue score (VAS 0–10) of 0.7 (0–4) at rest, 0.25 (0–4) at night, 3.0 (0–10) carrying heavy objects and 2.75 (0–10) during repetitive movement. 4 of 24 (16.7%) reported minor functional impairment. 3 of 24 (12.5%) patients requested orthopaedic review, but all were satisfied with outcome, seeking reassurance and discharged without any intervention. 3 of 24 (12.5%) were unhappy with their progress, but all had suffered from chronic pain or psychological conditions predating their injury. When offered further review, none of these patients accepted.

22 (91%) were satisfied with their treatment and 23 (95.8%) returned to work and hobbies. This data suggests routine discharge from A&E with advice does not compromise care, as no intervention is usually required beyond advice. These findings have obvious positive clinical and financial implications in streamlining clinical workload.

Conventional computer navigation systems using bone fixation have been validated in measuring anteroposterior (AP) translation of the tibia. Recent developments in non-invasive skin-mounted systems may allow quantification of AP laxity in the out-patient setting.

We tested cadaveric lower limbs (n=12) with a commercial image free navigation system using passive trackers secured by bone screws. We then tested a non-invasive fabric-strap system. The lower limb was secured at 10° intervals from 0° to 60° knee flexion and 100N of force applied perpendicular to the tibial tuberosity using a secured dynamometer. Repeatability coefficient was calculated both to reflect precision within each system, and demonstrate agreement between the two systems at each flexion interval. An acceptable repeatability coefficient of ≤3mm was set based on diagnostic criteria for ACL insufficiency when using other mechanical devices to measure AP tibial translation.

Precision within the individual invasive and non-invasive systems measuring AP translation of the tibia was acceptable throughout the range of flexion tested (repeatability coefficient ≤1.6 mm). Agreement between the two systems was acceptable when measuring AP laxity between full extension and 40° knee flexion (repeatability coefficient ≤2.1 mm). Beyond 40° of flexion, agreement between the systems was unacceptable (repeatability coefficient >3 mm).

These results indicate that from full knee extension to 40° flexion, non-invasive navigation-based quantification of AP tibial translation is as accurate as the standard invasive system, particularly in the clinically and functionally important range of 20° to 30° knee flexion. This could be useful in diagnosis and post-operative follow-up of ACL pathology.

Frail patients with neck of femur fracture often present to Accident & Emergency (A&E) with concomitant medical problems and are frequently fast-tracked to orthopaedic wards to achieve government waiting time targets.

This is a second cycle of audit since 2008 examining the safety of fast-tracking following several critical incidents. Data was collected prospectively between March and June 2011 by the first on-call orthopaedic doctor.

56 patients (12 male), average age 81.2y (50–97) were fast-tracked. 52 were correctly referred as having intra/extracapsular fracture; 4 patients did not have neck of femur fracture, but did have other medical problems. On arrival to the ward, 8 patients demonstrated abnormal symptoms, signs and vital observations requiring immediate review from the receiving physicians. For the 56 patients, a total of 448 mandatory points of protocol (e.g. intravenous access) should have been addressed prior to transfer; 150 were omitted (33.5%). Vital observations of patients fast-tracked after 2100h were worse (MEWS range 0 to 11) when compared with those fast-tracked prior to 2100h (MEWS range 0 to 3).

Fast-tracking is a common practice amongst many district-general and some teaching hospitals in Scotland. These data support concerns from orthopaedic surgeons and highlight the need for more complete management by A&E and, if necessary, referral to receiving medical staff prior to ward transfer. Early medical optimisation of acute and chronic comorbidities common to these patients is the main facilitator of early surgery. The evidence base demonstrates early surgery is a major variable in reducing post-operative mortality.

Introduction

The superficial anterior vasculature of the knee is variably described; most of our information comes from anatomical literature. Descriptions commonly emphasise medial-dominant genicular branches of the popliteal artery. Quantifying the relative contribution of medial and lateral vessels to the anastomotic network of the anterior knee may help provide grounds for selecting one of a number of popular incisions for arthrotomy.

The superficial anterior vasculature of the knee is variably described; most of our information comes from anatomical literature. Descriptions commonly emphasise medial-dominant genicular branches of the popliteal artery. Describing the relative contribution of medial and lateral vessels to the anastomotic network of the anterior knee may help provide grounds for selecting one of a number of popular incisions for arthrotomy.

The aim of this study is to describe the relative contribution of vessels to anastomoses supplying the anterior knee.

Cadaveric knees (n = 16) were used in two cohorts. The first cohort (n = 8) were injected at the popliteal artery with a single colour of latex, and then processed through a modified diaphanisation technique (chemical tissue clearance) before final dissection and analysis. This was repeated for the second cohort, but with initial dissection to identify potential source vessels at their origin. Each source vessel was injected with a different colour of latex. The dominant sources were determined in each specimen.

The majority of the specimens (n = 13; 81%) demonstrated that an intramuscular branch though the vastus medialis muscle was the dominant vessel. Anastomoses were most common over the medial side of the knee, both superiorly and inferiorly (3-5 anastomoses in all cases). Anastomosis over the lateral knee was infrequent (1 anastomosis in 1 specimen).

The results suggest that anterior vasculature of the knee is predominately medial in origin, but not from the genicular branches as previously described. This network of vessels found in the anterior knee is thought to be the main supply to the patella, extensor apparatus, anterior joint capsule and skin.

Optimum placement of incision for arthrotomy is a subject of debate. Considering the main blood supply to the anterior knee may help in choosing a particular approach.

Regional anaesthetic for foot surgery has been discussed as a method of post operative analgesia. Ankle block as the sole anaesthetic for foot surgery has not been extensively reviewed in the literature. We aimed to describe our experience of forefoot surgery under ankle block.

Sixty-six consecutive forefoot procedures (59 patients) were carried out under ankle block. Patients were contacted post operatively and completed a standardised questionnaire including an incremental pain assessment ranging from 0-10 (0 no pain, 10 severe pain).

Forty nine female and 10 male patients (age range 20-85y) were included. Procedures included 33 first metatarsal osteotomies, 15 cheilectomies, 3 first MTP joint replacements, 5 fusions, 4 excision of neuroma and 6 other procedures. 22 patients (33% of cases) reported discomfort during the block procedure (average pain score 1.5). 6 patients reported pain during their operation(s), average score 0.26. Average pain scores at 6, 12, 24 and 48 hours following surgery were 2.0, 3.2, 2.7 and 2.1 respectively. All patients were discharged home and walking on the same day. There were no readmissions. Each patient confirmed they would have surgery under regional block rather than general anaesthesia and would recommend this technique to family and friends.

There are many advantages in being able to perform these relatively small procedures under regional anaesthesia. The anaesthesia obtained permits the majority of forefoot procedures and provides lasting post-operative analgesia. Combined with intra-operative sedation, use of ankle tourniquet and same day discharge; it has very high patient acceptance and satisfaction.

Pedicle screw fixation is an effective and reliable method for achieving stabilization in lumbar degenerative disease. The procedure carries a risk of violating the spinal and neural canal which can lead to nerve injury. This audit examines the accuracy of screw placement using intra-operative image guidance.

Retrospective audit of patients undergoing lumbar pedicle screw fixation using image guidance systems over an 18-month period. Case records were reviewed to identify complications related to screw placement and post-operative CT scans reviewed to study the accuracy of screw position.

Of the 98 pedicle screws placed in 25 patients, pedicle violation occurred in 4 screw placements (4.1%). Medial or inferior breach of the pedicle cortex was seen in 2 screws (2%). Nerve root injury as a consequence of this violation was seen in one patient resulting in irreversible partial nerve root dysfunction. Mean set up time for the guidance system was 42 minutes. The mean operative time was 192 minutes.

Violation of either the medial or inferior pedicle cortex during placement of fixation screws is a rare, but potentially serious complication bearing lasting consequences. Image-guided placement can be helpful and possibly improve accuracy; particularly in patients with distorted spinal anatomy.

Regional anaesthetic for foot surgery has been discussed as a method of post operative analgesia. Ankle block as the sole anaesthetic for foot surgery has not been extensively reviewed in the literature.

Regional anaesthetic for foot surgery has been discussed as a method of post operative analgesia. Ankle block as the sole anaesthetic for foot surgery has not been extensively reviewed in the literature.

We aimed to describe our experience of forefoot surgery under ankle block alone. 21 consecutive forefoot procedures (18 patients) were carried out under ankle block. The blocks were performed by the senior authors. A mixture of 10ml 2% Lidocaine with 10ml 0.5 % Bupivacaine was administered to the superficial peroneal, deep peroneal, sural and saphenous nerves. Ankle tourniquet was employed in all procedures. The patients were contacted post operatively and completed a standardised questionnaire including an incremented pain assessment ranging from 0-10 (0 no pain, 10 severe pain). 17 female and 1 male patients were contacted (age range 33-67y). Procedures included 13 first metatarsal osteotomies, 3 cheilectomies, 2 first MTP joint replacements, and 5 fusions. 14 patients requested a short acting sedative (midazolam). 5 patients (27 %) reported some discomfort during the block procedure (average pain score 1.2). No patients reported any pain during their operation(s). 4 patients (22%) required supplementation of the block. Average pain score at 6, 12, 24 and 48 hours following surgery were 0.66, 2.9, 2.4 and 1.3 respectively. All patients were discharged home and walking on the same day. None complained of nausea or required parenteral analgesia; there were no readmissions. Each patient confirmed they would have surgery under local block rather than general anaesthesia and would recommend this technique to family and friends.

Forefoot surgery under ankle block alone is safe and effective. Anaesthesia obtained permits the majority of forefoot procedures and provides lasting post-operative analgesia. Combined with intraoperative sedation, use of ankle tourniquet and same day discharge, it has very high patient acceptance and satisfaction.

Purpose: Traditionally, the accepted treatments for adolescent idiopathic scoliosis (AIS) have included open anterior thoracotomy with instrumentation and posterior spinal fusion and instrumentation. Thoracoscopic instrumentation is a newer technique, whose role remains controversial. This systematic review of the literature aims to better understand thoracoscopic instrumentation as a treatment for AIS and to discuss it in the context of the alternative techniques currently used.

Method: The most commonly used medical databases (PUBMED, Medline, EMBASE, Cinahl, and the Cochrane library) were searched up to April 2008 using the search terms “VATS”, “thoracoscopic scoliosis” and “thoracoscopic scoliosis instrumentation”. Two reviewers independently performed the literature evaluation. There were no language restrictions. Because the number of randomized controlled trials was anticipared to be small, we included relevant non-randomized trials, observational studies, and uncontrolled studies.

Results: Eleven studies met the strict inclusion criteria for the systematic review, of which the majority were level III and IV evidence. Four hundred and forty-five cases have been reported, 80% of them female, with the vast majority having a diagnosis of AIS. Similar surgical techniques were used and had a mean operative time of 355 minutes, mean blood loss of 444 ml, and mean hospital stay of 5.1 days. Mean pre-operative curve magnitude was 47.9o; post-operative curve magnitude was 16.3o, with a correction of 62%. Number of levels instrumented was 6.3, pulmonary function testes returned to pre-operative values by 2-years post-operative, and complication rate was 21.6%, including a pulmonary complication rate of 9.2%. SRS questionnaires revealed that patients were satisfied.

Conclusion: The major drawbacks of the thoraco-scopic approach are the operative time and incidence of early pulmonary complications. Advantages include: minimally invasive, less blood loss, short hospital stay, excellent curve correction, few levels fused, good patient satisfaction, and no long term effect on pulmonary function. With appropriate surgeon training, careful patient selection, and precise surgical technique, this technique can offer an acceptable alternative to the more traditional procedures.

Purpose: Subacromial impingement syndrome is a painful condition which occurs during overhead activities as the rotator cuff is compressed between the greater tuberosity and the acromion. Unrecognized secondary causes of impingement syndrome may lead to treatment failure. Posterior capsular tightness, believed to alter shoulder joint kinematics, is often cited as a secondary cause but scientific evidence is lacking. The objective of this study was to evaluate the effect of posterior capsular tightness on pressure in the subacromial space.

Method: Ten fresh-frozen cadaver shoulder specimens were mounted on a custom testing apparatus. With the scapula fixed, the deltoid and cuff muscles were loaded statically with a constant ratio to elevate the humerus in the scapular plane under physiologic loading conditions. For each treatment (intact capsule, 1cm and 2cm plication), pressure in the subacromial space and glenohumeral kinematics were recorded during elevation. The treatment order was randomly assigned to each specimen. Peak pressure and translation of the humeral head center were compared using a repeated measures ANOVA.

Results: Peak subacromial pressures (mean±sd) were similar between treatment groups: 345±152 kPa, 410±213 kPa and 330±164 kPa for the intact, 1cm and 2cm plication respectively (p> 0.05). No significant differences were found for superior or antero-posterior translations of the humeral head at the peak pressure position (p> 0.05).

Conclusion: Posterior capsular tightness, as a sole variable, did not contribute significantly to increased pressure in the subacromial space or to increased anterior or superior humeral head translation during abduction. Clinically, posterior capsular tightness may occur in association with impingement syndrome but may not play a significant role in causation.