The posterior compartments of the knee are currently accessed arthroscopically through anterior, posteromedial or posterolateral portals. A direct posterior portal to access the posterior compartments has been overlooked due to a perceived high-risk of injury to the popliteal neurovascular structures. Therefore, this study aimed to investigate the safety and accessibility of a direct posterior portal into the knee.

This cross-sectional study comprised a sample of 95 formalin-embalmed cadaveric knees and 9 fresh-frozen knees. Cannulas were inserted into the knees, 16mm from the vertical plane between the medial epicondyle of the femur and medial condyle of the tibia and 8 and 14mm (females and males respectively) from the vertical plane connecting the lateral femoral epicondyle and lateral tibial condyle. Landmarks were identified in full extension and cannula insertion was completed with the formalin-embalmed knees in full extension and the fresh-frozen in 90-degree flexion. Posterior aspects of the knees were dissected from superficial to deep, to assess potential damage caused by cannula insertion. Incidence of neurovascular damage was 9.6% (n=10); 0.96% medial cannula and 8.7% lateral cannula. The medial cannula damaged one small saphenous vein (SSV) in a male specimen. The lateral cannula damaged one SSV, 7 common fibular nerves (CFN) and both CFN and lateral cutaneous sural nerve in one specimen. All incidences of damage occurred in formalin-embalmed knees. The posterior horns of the menisci were accessible in all specimens.

A medial-lying direct posterior portal into the knee is safe in 99% of occurrences. The lateral-lying direct posterior portal is of high risk to the CFN.

Knee arthroscopy is typically approached from the anterior, posteromedial and posterolateral portals. Access to the posterior compartments through these portals can cause iatrogenic cartilage damage and create difficulties in viewing the structures of the posterior compartments. The purpose of this study was to assess the feasibility of needle arthroscopy using direct posterior portals as both working and visualising portals.

For workability, the needle scope was inserted advanced from anterior between the cruciate ligament bundle and the lateral wall of the medial femoral condyle until the posterior compartments were visualised. For visualisation, direct postero-lateral and -medial portals were established. The technique was performed in 9 knees by two experienced researchers.

Workability and instrumentation of the posteromedial compartment and meniscus was achieved in 56%. The posterior horns could not be visualised in four specimens as the straight lens could not provide a more medial field of view. Visualisation from the direct medial posterior portal allowed a clear view of the medial meniscus, femoral condyle and posterior cruciate ligament in all specimens. Workability and instrumentation of the posterolateral compartment was not possible with the needle scope.

Direct posterior approaches for the posteromedial compartment access are challenging with the current needle scope options and could only be achieved in over 50%. The postero-lateral compartment was not accessible. An angled lens or a flexible Needle scope would be better suited for developing this technique further.

Objectives. Acetabular retractors have been implicated in damage to the femoral and obturator nerves during total hip replacement. The aim of this study was to determine the anatomical relationship between retractor placement and these nerves. Methods. A posterior approach to the hip was carried out in six fresh cadaveric half pelves. Large Hohmann acetabular retractors were placed anteriorly, over the acetabular lip, and inferiorly, and their relationship to the femoral and obturator nerves was examined. Results. If contact with bone was not maintained during retractor placement, the tip of the anterior retractor had the potential to compress the femoral nerve by passing superficial to the iliopsoas. If pressure was removed from the anterior retractor, the tip pivoted on the anterior acetabular lip, and passed superficial to the iliopsoas, overlying and compressing the femoral nerve, when pressure was reapplied. The inferior retractor pierced the obturator membrane in all specimens medial to the obturator nerve, with subsequent retraction causing the tip to move laterally, making contact with the nerve. . Conclusion. Iliopsoas can only offer protection to the femoral nerve if the retractor passes deep to the muscle bulk. The anterior retractor should be reinserted if pressure is removed intra-operatively. Vigorous movement of the inferior retractor should be avoided. Cite this article: Bone Joint Res 2014;3:212–6

This study aimed to describe the morphology of the coracoid process and determine the frequency of commonly observed patterns. The second purpose was to determine the location of inferior tunnel exit with superior based tunnel drilling and the superior tunnel exit with inferior based tunnel drilling.

A sample of 100 dry scapulae for the morphology aspect and 52 cadaveric embalmed shoulders for tunnel drilling were used. The coracoid process was described qualitatively and categorized into 6 different shapes. A transcoracoid tunnel was drilled at the centre of the base. Twenty-six shoulders were used for the superior-inferior tunnel drilling approach and 26 for the inferior-superior tunnel drilling approach. The distances to the margins of the coracoid process, from both the entry and exit points of the tunnel, were measured.

Eight coracoid processes were of convex shape, 31 of hooked shape, 18 of irregular shape, 18 of narrow shape, 25 of straight shape, and 13 of wide shape. The mean difference for the distances between superior entry and inferior exit from the apex was Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation 3.65+3.51mm (p=0.002); 1.57+2.27mm for the lateral border (p=0.40) and 5.53+3.45mm for the medial border (p=0.001). The mean difference for the distances between inferior entry and superior exit from the apex was 16.95+3.11mm (p=0.0001); 6.51+3.2mm for the lateral border (p=0.40) and 1.03+2.32 mm for the medial border (p=0.045).

The most common coracoid process shape observed was a hooked pattern. Both superior to inferior and inferior to superior tunnel drilling directed the tunnel from a more anterior and medial entry to a posterior-lateral exit. Superior to inferior drilling resulted in a more posteriorly angled tunnel. With inferior to superior tunnel drilling cortical breaks were observed at the inferior and medial margin of the tunnel.

The minimally invasive total hip replacement has been developed over the last years. The advantages of minimally invasive approaches concern reduced blood loss and pain, shorter operative time, reduced length of stay, facilitated rehabilitation and increased patient satisfaction. Potential disadvantages are the need for additional training and patient education, the insufficient clinical data and the risk of compromising the final result by giving more importance to the length of incision than to the damage of the deeper tissue. In the majority of cases, the minimally invasive techniques utilize standard prosthesis and resection of pathological tissue, including part of normal bone such as the femoral neck. LINK MIT-H permits combining a minimally invasive approach with the insertion of a T.O.P. acetabular cup and a CFP femoral prosthesis, preserving the femoral neck. The conservation of this anatomic part facilitates a shallow entry of the prosthesis in the femoral canal, preserving the bone stock and thereby allowing a more precise reconstruction of the hip geometry. The technique appears to give good results, associating the advantages of minimally invasive surgery with the preservation of the femoral neck. The good relation between the abductor lever arm and the adductor lever arm guarantees an elevated functional restoration, allowing a favorable and durable result in time. The LINK MIT-H technique may be utilized with a direct lateral or through a post-lateral approach. We prefer a lateral approach, usually utilizing general instruments such as hooks and Hohmann retractors where the width of instruments is adapted to the length of incision. A corkscrew may be useful to take out the femoral head, cutting it in the narrow part of the neck. Stein-mann pins, placed at the cranial acetabular rim as self-retaining retractors, associated with two Hohmann retractors below, allow good vision and facilitate reaming the socket. The attachment of fibre optics on the retractors is useful to have more light inside. Straight or cranked shaft instruments are very well suited in reaming and in aligning the T.O.P. acetabular cup. The minimally invasive technique gives the best results when damaging tissues as little as possible by using a less invasive prosthesis that is easily implanted in small spaces and only replaces the pathologic bone, thereby saving the bone stock best as possible in restoring the hip geometry

The purpose of this study was to develop a quality appraisal tool for the assessment of laboratory basic science biomechanical studies.

Materials andScore development comprised of the following phases: item identification/development, item reduction, content/face/criterion validity, weighting, test-retest reliability and internal consistency. For item identification/development, the panel was asked to independently list criteria and factors they considered important for cadaver study and generate items that should be used to appraise cadaver study quality. For content validity, the content validity ratio (CVR) was calculated. The minimum accepted content validity index (CVI) was set to 0.85. For weighting, equal weight for each item was 6.7% [15 items]. Based on these figures the panel was asked to either upscale or downscale the weight for each item ensuring that the final sum for all items was 100%. Face validity was assessed by each panel member using a Likert scale from 1–7. Strong face validity was defined as a mean score of >5. Test-retest reliability was assessed using 10 randomly selected studies. Criterion validity was assessed using the QUACS scale as standard. Internal consistency was assessed using Cronbach's alpha.

Five items reached a CVI of 1 and 10 items a CVI of 0.875. For weighting five items reached a final weight of 10% and ten items 5%. The mean score for face validity was 5.6. Test-retest reliability ranged from 0.78–1.00 with 9 items reaching a perfect score. Criterion validity was 0.76 and considered to be strong. Cronbach's alpha was calculated to be 0.71 indicating acceptable internal consistency.

The new proposed quality score for basic science studies consists of 15 items and has been shown to be reliable, valid and of acceptable internal consistency. It is suggested that this score should be utilised when assessing basic science studies.

Introduction: Correct placement of the acetabular cup is a crucial step in total hip replacement to achieve a satisfactory result and remains a challenge with free hand techniques. Imageless navigation may provide a viable alternative to freehand technique and improve placement significantly. The purpose of this study therefore was to assess and validate intra-operative placement values as displayed by the navigation unit to postoperative measurement of cup position using high resolution CT scans.

Methods: 32 patients underwent primary hip joint replacement using imageless navigation. The average age was 66.5 years (range 32–87). 23 non-cemented and 9 cemented acetabular cups were implanted. During surgery we aimed for 45 degrees of inversion and 15 degrees of anteversion. A pelvic CT scan using a multi-slice CT was used to assess the position of the cup radiographically.

Results: 2 patients were excluded because of dislodgement of the tracking pin. Pearson correlation revealed a strong significant correlation (r=0.68; p< 0.006), for cup inclination and a moderate non-significant correlation (r=0.53; p=0.45) between intra-operative readings and cup placement.

Discussion: These findings can be explained with possible introduction of systematic error. Even though the acquisition of anatomic landmarks are simple they must be acquired with great precision. An error of 1 cm can result in a mean anteversion error of 6 degrees and inclination error of 2.5 degrees. Whilst navigation results in highly accurate cup placements in relation to inclination, ante-version of the cup can not be determined accurately.

Introduction: Malpositioning of the acetabular cup component in total hip arthroplasty can result in increased wear, early nonseptic loosening and is the most common cause of dislocation. Previous research has defined a safe zone with an inclination of 40±10 degrees and anteversion of 15±10 degrees. The purpose of this study was to compare cup placement using imageless navigation to a historical control group using CT based measurements.

Methods: 34 patients receiving a primary hip replacement between June 2005 and December 2006 were enrolled in the study. Alignment of the implant is based on the acquisition of landmarks (ASIS and pubic tubercle) and placement of tracking pins into the ASIS. The target position for all patients was 45 degrees of inclination and 15 degrees of anteversion. The position was determined by postoperative Ct scans of the pelvis. This group was compared to a matched control group.

Results: Descriptive statistics revealed that the demographics of both groups were comparable. Mean cup placement in the navigation group was 46.6±5.9 deg of inclination and 18.8±5.6 deg of anteversion. Mean cup placement in the control group was 48.4±8.85 deg of inclination and 22.33±10.9 deg of anteversion. With navigation 73.7% resp 89.5% of cups were placed within the safe zone for inclination resp. anteversion whereas only 56.2% resp. 50% of cups were placed with freehand technique. Taking both inclination and anteversion into consideration 68.4% of cups were placed in the safe zone with navigation. Only 12.5% were placed for both inclination and anteversion were placed into the safe zone.

Discussion: Computer navigation for total joint arthroplasty, if helpful to the surgeon, has to increase reliability of component placement and show a significant reduction in variation compared to freehand techniques. Our results demonstrate that imageless navigation is a reliable tool which significantly increases precision of acetabular cup placement. Further studies are needed to evaluate and further increase the accuracy of the system.

Large osteochondral defects of the femoral condyle still pose a difficult problem to treat. A variety of options is available but most of result in replacement with inferior fibrous or hyaline-like cartilage in the load-bearing zone of the knee joint. We present the five year results of Mega-OATS. This technique utilizes the posterior femoral condyle for coverage of osteochondral defects and is called Mega-OATS.

From July 1999, 33 patients of mean age 34.3 years (15–59) were treated with MEGA-OATS. Fifteen patients additionally underwent high tibial osteotomy and two bone grafting using bone harvested from the proximal tibia. The average defect size was 6.2±1.8 cm2. The mean follow up was 66.4±13.2 months. The technique calls for excision of the posterior femoral condyle which is placed in a specially designed work station.

The Lysholm score increased post-operatively from 49.0±19.4 to 88.5±14.9 12 months post surgery to 85.5±16.0 five years post surgery. Three months post-operatively, patients attained a full range of motion and became fully weight-bearing. There was no difference in patients undergoing combined surgery with high tibial osteotomy and patients undergoing Mega OATS as a single procedure after five years. No post-operative meniscal lesions of the posterior horn have been observed.

Mega-OATS achieves a congruent reconstruction of the articular surface in the load bearing zone of the femoral condyle. We consider it a good alternative and salvage procedure in the treatment of large osteochondral defects of the femoral condyle.

Acetabular retractors have been implicated in damage to the femoral and obturator nerves during total hip arthroplasty (THA). Despite this association, the anatomical relationship between retractor and nerve has not been elucidated. A posterior approach to the hip was carried out in 6 fresh frozen cadaveric hemi- pelvises. Large Hohmann acetabular retractors were placed anteriorly over the acetabular rim, and inferiorly, as per routine practice in THA. The femoral and obturator nerves were identified through dissection and their relationship to the retractors was examined. If contact with bone was not maintained during retractor placement, the tip of the anterior retractor had the potential to compress the femoral nerve, by passing either superficial to, or through the bulk of the iliopsoas muscle. If pressure was removed from the anterior retractor, the tip pivoted on the anterior acetabular lip, and passed superficial to iliopsoas, overlying and compressing the femoral nerve, when pressure was reapplied. The inferior retractor pierced the obturator membrane, medial to the obturator foramen in all specimens. Subsequent retraction resulted in the tip moving laterally to contact the obturator nerve. Both the femoral and obturator nerves are vulnerable to injury around the acetabulum through the routine placement of retractors in THA. The femoral nerve is vulnerable where it passes over the anterior acetabulum. Iliopsoas can only offer protection if the retractor passes deep to the muscle bulk. If pressure is removed from the anterior retractor intra-operatively it should be reinserted. The obturator nerve is vulnerable as it exits the pelvis through the obturator foramen. Vigorous movement of the inferior retractor should be avoided. Awareness of the anatomy around the acetabulum is essential when placing retractors

High tibial osteotomies are commonly performed for varus/valgus malalignment of the knee. In the past we have been well aware that a high tibial osteotomy corrects the coronal plane but we did not consider changes of the tibial slope. Altering the slope has an impact on the in situ forces of the cruciate ligaments and influences the stability of the knee. The purpose of this study was to investigate the amount of alteration of the tibial slope by a closed wedge osteotomy.

From January 2001 to September 2001 we reviewed retrospectively all Xrays of patients that underwent a high tibial osteotomy or were admitted for removal of hardware. 80 patients were included. 67 patients could be followed up.

The slope on the preoperative xrays was 6,1 degrees (0–12). A closed wedge osteotomy decreased the slope by a mean of 4,88 degrees. A high tibial osteotomy of six degrees in the coronal plane decreased the slope by 4.29 degrees, a HTO of eight degrees decreased the slope by 7 degrees, a HTO of ten degrees by altered the slope by 4.75 and of twelve degrees by decreased the slope by 6.5 degrees.

A closed wedge osteotomy decreases the tibial slope. It is the preferred technique when a combined procedure (HTO and ACL reconstruction) is planned. There is no correlation between the degree of correction of the coronal plane by a closed wedge high tibial osteotomy and changes of the tibial slope.

Traumatic shoulder dislocations at young age result in a significant re-dislocation rate and lead to chronic instability. Conservative treatment fails in 25–96% of cases especially in young active patients. The accepted standard treatment is the classical open Bankart repair which almost always results in loss of motion. The development of new techniques and devices has lead to an increase in arthroscopic techniques for shoulder stabilisations.

Between September 1996 and October 2000 262 arthroscopic shoulder stabilisations were performed by the senior author: 159 cases FASTak® titanium anchors, 26 Panalok® anchors and 57 cases Suretac® anchors were used. Minimum follow up was 12 months with a mean follow up of 24.9 months (12–50). Rowe score and a visual analogue scale was used to measure patient satisfaction.

The Rowe score increased to 83,1 +/− 20,9. The visual analogue score demonstrated overall patient satisfaction. Complications included redislocations(4.7%) sub-luxations (6.3%) and ongoing instability (6.3%). Return to sports occurred in 89.1% of patients with 68.4% being able to return to their previous sports activity level.

This study demonstrates that arthroscopic shoulder stabilisation is comparable to the gold standard open Bankart repair. It is associated with a high patient satisfaction, lower morbidity, faster return to the previous activity level, better range of motion and less postoperative pain. The disadvantage of the technique is a long learning curve and the potentially longer operating times.

Introduction High tibial osteotomies (HTO) are commonly performed for either varus or valgus malalignment of the knee. In the past we have been well aware that HTO corrects the coronal plane of the knee, but we did not consider changes of the tibial slope in the sagittal plane when planning or evaluating osteotomies. Because the tibia is a three-dimensional structure with a triangular shape, osteotomy may result in changes in both the coronal plane and the sagittal plane. Altering the tibial slope has an impact on the in situ forces of the cruciate ligaments and may influence the stability of the knee. The purpose of this study is to investigate any possible alteration of the tibial slope introduced by HTO.

Methods This study was conducted as a retrospective radiographic review of a consecutive series of patients. Between January and September 2001 a total of 80 patients underwent either HTO or the removal of hardware from a prior HTO. The radiographs of 67 of these patients were suitable for review. There were 41 males with an average age of 36.6 years (17 to 67). There were 26 females with an average age of 39.4 years (19 to 62). Routine radiographs of the knee were obtained using standard methods, and these were assessed by comparison to corresponding preoperative studies.

Results The posterior slope on pre-operative radiographs averaged 6.1° (0 to 12). HTO using a closing wedge technique was found to decrease this posterior slope by a mean of 4.9°. The change in the posterior slope was not found to correlate directly with the magnitude of the correction in the coronal plane. HTO of six degrees in the coronal plane decreased the posterior slope by 4.3° degrees, HTO of eight degrees decreased the posterior slope by seven degrees, HTO of 10° altered the slope by 4.8° degrees, and HTO of 12° degrees decreased the posterior slope by 6.5°.

Conclusions HTO by a closing wedge technique for sagittal plane correction often distorts alignment in the coronal plane as well, resulting in a decrease in the normal posterior tibial slope. We found no direct correlation between the degree of correction of the coronal plane and alteration of the tibial slope. Decreasing this slope potentially decreases in situ forces acting on the ACL while simultaneously increasing forces acting on the PCL. This may have advantages when managing combined cases with both malalignment and instability. The closing wedge technique is our preferred method when a combined procedure (HTO and ACL reconstruction) is planned.

In relation to the conduct of this study, one or more of the authors has received, or is likely to receive direct material benefits.

It is suggested that there is a link between arch type of the foot and overuse injuries. The use of individual selected running shoes can reduce running injuries substantially. To select the correct shoe the runner needs to have appropriate knowledge of his own foot anatomy and biomechanics. A questionnaire was used to investigate the knowledge of the runner about his arch height and biomechanics of running. Clinical examination was performed by 5 orthopaedic surgeons and experienced orthopaedic technicians. Weight-bearing podograms were used to further define the deformity.

We examined 92 volunteers with a mean age of 35.4 (12–63) years, a mean size of 176 cm (154–195) with a mean body weight of 70.38 kg (45–95). Eighteen out of 47 runners with a flatfoot deformity identified their deformity correctly. Twenty five out of 43 volunteers with a normal arch were correct in assessing their foot. Two runners with a cavus foot were correct in identifying their foot. Only 4 out of 38 runners that diagnosed themselves as being pronators have been found to be pronators. Four runners with a self-diagnosed non-pro-nating foot were classified as being pronators. Three runners that could not classify themselves were diagnosed as pronators.

This study demonstrates the poor knowledge of foot deformities in the running community.

High tibial osteotomy is commonly performed for varus/ valgus misalignment of the knee. Altering the sagittal plane can affect the forces of the cruciate ligaments and influence stability. This retrospective study looked at the alteration of the tibial slope produced by closed wedge osteotomy, in which the importance of the sagittal plane is often overlooked.

We followed-up 67 of 80 patients admitted for high tibial osteotomy or removal of hardware between January and September 2001. The mean age of the 41 men was 36.6 years (17 to 67) and of the 26 women 39.4 years (19 to 62).

On preoperative radiographs the mean slope was 6.1( (0( to 12(). The frontal plane was changed by a mean of 7.93( (2( to 12(). A closed wedge osteotomy decreased the slope by a mean of 4.88( (0( to 10( posteriorly and 0( to 6( anteriorly). Alteration of the coronal plane by 6( decreased the slope by 4.29(, 8( by 7(, 10( by 4.75( and 12( degrees by 6.5(.

A closed wedge osteotomy decreases the tibial slope. This causes an anterior shift in the starting position of the tibia, potentially decreasing in situ forces acting on the anterior cruciate ligament. There was no correlation between the correction of the coronal plane and alteration of the sagittal plane.

It is suggested that there is a link between overuse injuries and the type of arch of the foot, and that the use of appropriate running shoes may reduce running injuries substantially. However, to select the correct shoe, a runner needs knowledge of the anatomy and biomechanics of his/her foot.

Five orthopaedic surgeons and experienced orthopaedic technicians examined the feet of 92 runners of mean age 35.4 years (12 to 63), mean height 176 cm (154 to 195) and mean body weight 70.38 kg (45 to 95). Weight-bearing podograms were used to define deformities of the feet further. A questionnaire ascertained what runners knew about their arch heights and the biomechanics of running. Of 43 volunteers with normal arches, 25 correctly assessed their feet, but only 18 of 47 runners with a flatfoot deformity identified their deformity. Two runners with a cavus foot identified it correctly. Only four of 38 runners who diagnosed themselves as pronators were found to be, and four runners who self-diagnosed non-pronation were classified as pronators. Three runners who could not classify themselves were diagnosed as pronators.

This study demonstrates the poor knowledge of foot deformities in the running community.

Purpose:

Imageless navigation has improved the accuracy of acetabular cup placement but relies on manual identification of pelvic anatomy. Thick soft tissues in obese patients could obscure these landmarks and result in large variances of cup placement. The purpose of this study was to investigate the relationship between BMI, soft tissue thickness, navigated cup and final post-operative cup position.

Purpose:

Correct placement of the acetabular cup is a crucial step in hip replacement to achieve a satisfactory result and remains a challenge with free hand techniques. Imageless navigation may provide a viable alternative to freehand technique and improve placement significantly. The purpose of this project was to assess and validate intra-operative placement values as displayed by an imageless navigation system to postoperative measurement of cup position using high resolution CT scans.

Introduction:

Gait analysis is an important tool to measure function following total knee replacement. It is currently unknown whether there is a correlation between subjective and objective outcome. The purpose of this study was to analyse relationships between subjective outcome scores and kinematic and kinetic data.

Background:

The aim of this study was to investigate the outcome after ACL reconstruction between a group of patients receiving a standardized supervised physiotherapy guided rehabilitation program and a group of patients who followed an un-supervised, home-based rehabilitation program.