As it remains unproven that hypermobility of the first tarsometatarsal joint (TMTJ-1) is a significant factor in hallux valgus deformity, the necessity for including arthrodesis of TMTJ-1 as part of a surgical correction of a hallux valgus is questionable. In order to evaluate the role of this arthrodesis on the long-term outcome of hallux valgus surgery, a prospective, blinded, randomised study with long-term follow-up was performed, comparing the Lapidus procedure (which includes such an arthrodesis) with a simple Hohmann distal closing wedge metatarsal osteotomy. The study cohort comprised 101 feet in 87 patients: 50 feet were treated with a Hohmann procedure and 51 with a Lapidus procedure. Hypermobility of TMTJ-1 was assessed pre-operatively by clinical examination. After a mean of 9.25 years (7.25 to 11.42), 91 feet in 77 patients were available for follow-up. There was no difference in clinical or radiological outcome between the two procedures. Also, there was no difference in outcome between the two procedures in the subgroup clinically assessed as hypermobile. This study does not support the theory that a hallux valgus deformity in a patient with a clinically assessed hypermobile TMTJ-1 joint requires fusion of the first tarso-metatarsal joint. Cite this article: Bone Joint J 2013;95-B:1222–6

In a retrospective study we compared the results of 31 Wilson and 31 Hohmann osteotomies of the first metatarsal in the treatment of hallux valgus. There were no differences between the two operations in terms of patient satisfaction, pain relief, appearance, footwear and walking ability. First metatarsal shortening was the same after both operations, and the degree of shortening was unrelated to either the clinical or the pedobarographic findings. Although the long-term radiographic changes after the Hohmann osteotomy were more worrying, the pedobarographic patterns tended to be worse after the Wilson osteotomy. There were no poor results and the numbers of feet with the same final grade were identical in each group. However, there was abnormal loading of the lateral metatarsal heads after both osteotomies when compared with the normal foot, and hallux-contact time during the stance phase was also significantly reduced after osteotomy

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.

Aims

The primary objective of this study was to develop a validated classification system for assessing iatrogenic bone trauma and soft-tissue injury during total hip arthroplasty (THA). The secondary objective was to compare macroscopic bone trauma and soft-tissues injury in conventional THA (CO THA) versus robotic arm-assisted THA (RO THA) using this classification system.

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