Background

Artificial total knee designs have revolutionized over time, yet 20% of the population still report dissatisfaction. The standard implants fail to replicate native knee kinematic functionality due to mismatch of condylar surfaces and non-anatomically placed implantation. (Daggett et al 2016; Saigo et al 2017). It is essential that the implant surface matches the native knee to prevent Instability and soft tissue impingement. Our goal is to use computational modeling to determine the ideal shapes and orientations of anatomically-shaped components and test the accuracy of fit of component surfaces.

INTRODUCTION

The major loss of articular cartilage in medial osteoarthritis occurs in a central band on the distal femur, and in the center of the tibial plateau (Figure). This is consistent with varus deformity due to cartilage loss and meniscal degeneration, together with the sliding regions in walking. Treatment at an early stage such as KL grade 2 or 3, has the advantages of little bone deformity and cruciate preservation, and could be accomplished by resurfacing only the arthritic areas with Early Intervention (EI) components. Such components would need to be geometrically compatible with the surrounding bearing surfaces, to preserve continuity and stability. However because of the relatively small surface area covered, compared with total knees and even unicompartmentals, it is hypothesized that EI components will be an accurate fit on a population of knees with only a small number of sizes, and that accuracy can be maintained without requiring right-left components. We examined this hypothesis using unique design and methodology.

Purpose: The Instability Severity Index Score (ISIS) is a 6-item questionnaire that has been reported to predict failure of arthroscopic Bankart repair among patients treated for recurrent anterior glenohumeral instability. Two of the ISIS items pertain to radiographic features (presence of a Hill-Sachs lesion, loss of glenoid contour). These, however have yet to be validated. The goal of this study was to examine the inter – and intra-rater agreement and corresponding reliability of the radiographic aspects of the ISIS.

Method: Fifty-two plain, randomly selected, true antero-posterior radiographs in 45° gleno-humeral external rotation were evaluated by five assessors (three upper extremity orthopaedic surgeons, one senior orthopaedic resident and one musculoskeletal radiologist). Radiographs were retrieved for patients with documented recurrent shoulder instability requiring surgical stabilization and placed in a blinded Microsoft Powerpoint presentation for evaluation. Assessors were asked to determine the presence/absence of a Hill-Sachs lesion and if a loss of glenoid contour was present. Radiographs were evaluated in random order on two occasions, separated by a one-week time interval. Intra – and inter-rater reliability was assessed using percentage of agreement and kappa statistics.

Results: For session one, the number of Hill-Sachs lesions observed among raters ranged from 11 to 32. This resulted in inter-rater agreement ranging from 48% to 78% (k = 0.07 to 0.42), indicating poor to fair reliability. Cases with loss of glenoid contour ranged from seven to 14 with inter-rater agreement of 66% and 90% (k = 0.01 to 0.61), suggesting poor to moderate reliability. Session two led to modest increases in inter-rater agreement. The number of Hill-Sachs lesions observed ranged from four to 30 (agreement of 48% to 84%; k = 0.11 to 0.60) indicating fair to moderate reliability and the number of cases with loss of glenoid contour ranged from three to 14 (agreement of 66% to 94%; k = – 0.04 to 0.69), ranging from poor to moderate reliability. With respect to intra-rater reliability, agreement ranged from 71% to 94% (k = 0.41 to 0.86) for Hill-Sachs lesions, indicating fair to good reliability and 76% to 94% (k= 0.20 to 0.74) for loss of glenoid contour, ranging from fair to good reliability. Intra-rater agreement and corresponding kappa values were highest among the upper extremity surgeons and the musculoskeletal radiologist, particularly for loss of glenoid contour (85% to 94%; k = 0.56 to 0.74) suggesting there is moderate to good reliability in this measurement.

Conclusion: Our results indicate that the intra-rater reliability of the ISIS radiographic features was highest among upper extremity specialists and the musculoskeletal radiologist, suggesting that the ISIS may have utility in an experienced clinician’s individual practice. As the inter-rater reliability appears low, particularly for Hill-Sachs lesions, its wide-spread use across surgeons should be examined in further research.

Purpose: Due to its proximity to the glenohumeral joint, the suprascapular nerve may be at risk of iatrogenic nerve injury during arthroscopic labral repair. Our primary objective is to evaluate the risk of suprascapular nerve injury during standard drilling techniques utilized in arthroscopic superior labral repairs. Secondarily, we evaluated the correlation between this risk and scapular size.

Method: Forty-two cadaveric shoulders were dissected to isolate their scapulae. A surgical drill and guide was used to create suture anchor holes in 3 locations in the superior rim of the glenoids as typically done in arthroscopic superior labral repairs. The orientation of these drill holes correspond to common shoulder arthroscopic portals. The suprascapular nerve was then dissected from the suprascapular notch to the spinoglenoid notch. The presence of drill perforations through the medial cortex of the glenoid vault was recorded along with the corresponding hole depth and distance to the suprascapular nerve.

Results: Medial glenoid vault perforations occurred in 8/21(38%) cadavers with a total of 18/126(14%) perforations. The suprascapular nerve was in line of the drill path in 5/18(28%) perforations. Female specimens and smaller scapulae had a statistically higher risk of having a perforation (p< 0.05).

Conclusion: The results of this anatomic study suggest that there is a substantial risk of medial glenoid vault perforation. When a perforation does occur, the suprascapular nerve appears to be at high risk for injury especially with more posterior drill holes. The risk is significantly higher in females and in smaller scapulae.

Purpose of study: To determine whether positioning the operated limb in flexion on a CPM machine reduces blood loss following uncemented total knee replacement. We also sought to determine whether limb arterial pressure, represented by ankle-brachial pressure index (ABPI), is affected by position of the limb.

Methods: We compared two groups of age and sex matched patients undergoing uncemented total knee replacement. The control group were treated in the postoperative period with the leg positioned flat in extension (48 patients). The CPM group were placed on a CPM machine at 90° of knee flexion for twelve hours immediately post-operatively (46 patients). Haemoglobin and haematocrit levels, blood transfusion requirement, length of hospital stay, range of motion and complications were compared.

In addition, we measured ankle and brachial pressures in a separate group of 39 patients with the limb in three different positions: flat with the knee in extension (ABPI 1), raised with the knee in extension (ABPI 2), and finally with the knee flexed to 90° (ABPI 3).

Results: The CPM group demonstrated a smaller drop in haemoglobin level (2.5 vs 3.1, p=0.013) and a reduced blood transfusion requirement (3 patients vs 14 patients, p < 0.05) in the post-operative period when compared to the control group. There was no significant difference in haematocrit drop, discharge range of motion, complications or length of hospital stay between the two groups.

ABPI measurements were calculated in the standard fashion, the mean ABPI in each limb position being 1.17 (ABPI 1), 0.87 (ABPI 2) and 0.83 (ABPI 3) respectively.

Conclusions: Short-term use of a CPM machine in the post-operative period reduces blood loss and appears safe following uncemented total knee replacement. We found limb arterial pressure to be reduced to the greatest extent with the limb in a position of 90° flexion at the knee, which may account for the reduction in blood loss seen in the CPM group.

Antegrade intramedullary nailing via a piriformis fossa start point is the treatment of choice for most femoral shaft fractures in adults. Recently alternate approaches for intramedullary nailing of the femur have been advocated, including retrograde nailing and trochanteric start point antegrade nailing. Reasons cited for considering altenative starting points to the piriformis fossa include a concern about the damage to the hip abductor muscles that may occur during access to the piriformis fossa. There is very little literature about long- term muscle function after standard antegrade intramedullary nailing and the conclusions of the available studies are conflicting.

The purpose of this study was to document the hip abductor muscle strength following standard antegrade intramedullary nailing utilizing two different objective measures (KinCom and gait analysis).

Objective evidence of hip abductor muscle strength will assist in planning new nailing techniques.

Twenty-two patients with isolated femoral shaft fractures who were treated with standard antegrade reamed interlocking intramedullary nailing and who had a minimum one year follow-up were identified. The patients were examined for muscle strength, range of motion and limb length. All of the patients answered a questionnaire and completed the SF-36 and Musculoskeletal Functional Assessment outcome measures. All patients had isokinetic muscle testing of their hip abductors, hip extensors and knee extensors using the KinCom muscle testing machine. Ten of the patients also underwent formal gait lab analysis.

Isokinetic muscle testing showed no significant difference from the uninjured contralateral side in hip abduction, hip extension or knee extension. The gait lab analysis failed to show any important changes in gait pattern. SF-36 scores were comparable to norms. MFA scores did not indicate any significant long term disability.

Antegrade reamed interlocking intramedullary nailing of femoral shaft fractures utilizing a standard piri-formis fossa starting point is not associated with any significant long term hip abductor muscle strength deficit. Gait pattern returns to normal following femoral shaft fracture treated with this technique and functional outcomes are good.

Fifty-six patients, with a median fourteen years follow-up of isolated tibial shaft fracture treated with an IM nailing, underwent functional evaluation with SMFA and SF-36 questionnaires, as well as an injury specific questionnaire. Thirty-three also underwent clinical and radiological evaluation.

Overall, SF-36 scores (PCS 49.9, MCS 52.0) were near normal. Five (15.2%) had physical findings of venous stasis, while a third reported symptoms A third had at least mild OA on radiographs (knee-seven, ankle-eleven). A third of patients had a loss in ankle dorsiflexion, and more than half reported knee pain that was limiting to at least one activity.

We conducted a study to evaluate the long term functional outcomes and disabilities of patients with an isolated tibial shaft fracture treated with intramedullary nailing.

We identified two hundred and fifty eligible patients from the VGH Orthopaedic Trauma database between 1987 and 1992. A total of fifty-six patients agreed to participate. All were evaluated with the SF-36 and SMFA functional questionnaires, as well as an injury specific questionnaire focusing on knee pain, and symptoms of venous insufficiency. A sub-group of thirty-three patients were evaluated radiographically and by physical examination. We had a median follow-up of fourteen years, with a range from twelve to seventeen years.

The SF-36 scores (PCS 49.9, MCS 52.0) were comparable to population norms. Of the questionnaire group (n=56), fifteen denied knee pain with any activity, while twenty-nine had knee pain that was limiting to at least one type of activity. With respect to swelling, eighteen reported asymmetrical swelling affecting the injured limb. However, in the examination group, only five had objective evidence of venous stasis. Knee range of motion was essentially equivalent to the unaffected side, while thirteen patients had a restricted range of motion of the ankle. Radiographically, seven patients had at least mild OA of at least one knee compartment, while eleven had at least mild OA of the tibio-talar joint, despite near anatomic fracture healing.

At a median fourteen years following tibial nailing of isolated tibial fractures, patients function very well, but objective and subjective evaluation shows not insignificant sequellae.

Introduction and Aims: Recently alternate approaches for intra-medullary femoral nailing have been advocated, including retrograde nailing and trochanteric start point antegrade nailing in an attempt to avoid damage to the hip abductor muscles that may occur during access to the piriformis fossa. The aim of this study was to document the hip abductor muscle strength following standard antegrade intra-medullary nailing utilising two different objective measures.

Method: Twenty-two patients with isolated femoral shaft fractures who were treated with standard ante-grade reamed interlocking intra-medullary nailing and who had a minimum one-year follow-up were identified. The patients were examined for muscle strength, range of motion and limb length. All of the patients answered a questionnaire and completed the SF-36 and Musculoskeletal Functional Assessment outcome measures. All patients had isokinetic muscle testing of their hip abductors, hip extensors and knee extensors using the KinCom muscle testing machine. Eleven of the patients also underwent formal gait lab analysis.

Results: Isokinetic muscle testing showed no significant difference from the uninjured contralateral side in hip abduction, hip extension or knee extension. The gait lab analysis failed to show any important changes in gait pattern in the time spatial and hip moment parameters. SF-36 scores were comparable to norms (mean physical component score 53 and mean mental component 51). MFA scores did not indicate any significant long-term disability.

Conclusion:Antegrade reamed interlocking intra-medullary nailing of femoral shaft fractures utilising a standard piriformis fossa starting point is not associated with any significant long-term hip abductor muscle strength deficit. Gait pattern returns to normal following femoral shaft fracture treated with this technique and functional outcomes are good.