Aims

The objective of this study was to present the outcomes of rotational acetabular osteotomy (RAO) over a 30-year period for osteoarthritis (OA) secondary to dysplasia of the hip in pre- or early-stage OA.

Aim

Mesenchymal stem cells (MSCs) have several properties that may support their use as an early treatment option for osteoarthritis (OA). This study investigated the role of multiple injections of allogeneic bone marrow-derived stem cells (BMSCs) to alleviate the progression of osteoarthritic changes in the various structures of the mature rabbit knee in an anterior cruciate ligament (ACL)-deficient OA model.

Aims

The aim of this study was to report the long-term results of rotational acetabular osteotomy (RAO) for symptomatic hip dysplasia in patients aged younger than 21 years at the time of surgery.

Aims

To investigate the risk factors for progression of articular cartilage damage after anatomical anterior cruciate ligament (ACL) reconstruction.

Aims

Our aim was to evaluate the radiographic characteristics of patients undergoing total hip arthroplasty (THA) for the potential of posterior bony impingement using CT simulations.

Objectives

The objective of this study was to investigate the therapeutic effect of peripheral blood mononuclear cells (PBMNCs) treated with quality and quantity control culture (QQ-culture) to expand and fortify angiogenic cells on the acceleration of fracture healing.

Objectives

Regenerative medicine is an emerging field aimed at the repair and regeneration of various tissues. To this end, cytokines (CKs), growth factors (GFs), and stem/progenitor cells have been applied in this field. However, obtaining and preparing these candidates requires invasive, costly, and time-consuming procedures. We hypothesised that skeletal muscle could be a favorable candidate tissue for the concept of a point-of-care approach. The purpose of this study was to characterize and confirm the biological potential of skeletal muscle supernatant for use in regenerative medicine.

Background

The clinical results of total hip arthroplasty (THA) with a cementless prosthesis have been constantly improving due to progress in the area of stem design and surface finish. However, majority of stems are well-fixed with canal filling or diaphyseal fit, and cortical hypertrophy or metaphyseal bone atrophy has been often observed. Cementless Spotorno stem (CLS stem; Zimmer, Warsaw, USA) is a double-tapered rectangular straight stem. The purpose of this study is to investigate the mean 13 years' results of CLS stem and to evaluate the press-fit stability of CLS stem.

Introduction

Clione Anchored Replacement Prosthesis (CARP-H system) is a novel femoral implant for cementless fixation at the metaphysis of the proximal femur and preservation of cancellous bone of the femoral diaphysis is expected (Fig.1). We developed CARP-H system and started to use the prosthesis after the approval by Pharmaceuticals and Medical Devices Agency in 2012. This study examines the efficacy and short-term outcome of CARP-H system in a series of patients undergoing total hip arthroplasty (THA) or bipolar hemi-arthroplasty (BHA).

We report the clinical outcome and findings at second-look arthroscopy of 216 patients (mean age 25 years (11 to 58)) who underwent anterior cruciate ligament (ACL) reconstruction or augmentation. There were 73 single-bundle ACL augmentations (44 female, 29 male), 82 double-bundle ACL reconstructions (35 female, 47 male), and 61 single-bundle ACL reconstructions (34 female, 27 male).

In 94 of the 216 patients, proprioceptive function of the knee was evaluated before and 12 months after surgery using the threshold to detect passive motion test.

Second-look arthroscopy showed significantly better synovial coverage of the graft in the augmentation group (good: 60 (82%), fair: 10 (14%), poor: 3 (4%)) than in the other groups (p = 0.039). The mean side-to-side difference measured with a KT-2000 arthrometer was 0.4 mm (-3.3 to 2.9) in the augmentation group, 0.9 mm (-3.2 to 3.5) in the double-bundle group, and 1.3 mm (-2.7 to 3.9) in the single-bundle group: the result differed significantly between the augmentation and single-bundle groups (p = 0 .013). No significant difference in the Lysholm score or pivot-shift test was seen between the three groups (p = 0.09 and 0.65, respectively). In patients with good synovial coverage, three of the four measurements used revealed significant improvement in proprioceptive function (p = 0.177, 0.020, 0.034, and 0.026).

We conclude that ACL augmentation is a reasonable treatment option for patients with favourable ACL remnants.

Cite this article: Bone Joint J 2014;96-B:1325–32

Summary Statement

We evaluated the mechanical strength of two cortical suspension devices by reproducing clinical situation for ACL reconstruction. A most important factor affecting the displacement during cyclic load was the length of the tendon rather than the length of the device.

In Japan, osteoarthritis (OA) of the hip secondary to acetabular dysplasia is very common, and there are few data concerning the pathogeneses and incidence of femoroacetabular impingement (FAI). We have attempted to clarify the radiological prevalence of painful FAI in a cohort of Japanese patients and to investigate the radiological findings. We identified 176 symptomatic patients (202 hips) with Tönnis grade 0 or 1 osteoarthritis, whom we prospectively studied between August 2011 and July 2012. There were 61 men (65 hips) and 115 women (137 hips) with a mean age of 51.8 years (11 to 83). Radiological analyses included the α-angle, centre–edge angle, cross-over sign, pistol grip deformity and femoral head neck ratio. Of the 202 hips, 79 (39.1%) had acetabular dysplasia, while 80 hips (39.6%) had no known aetiology. We found evidence of FAI in 60 hips (29.7%). Radiological FAI findings associated with cam deformity were the most common. There was a significant relationship between the pistol grip deformity and both the α-angle (p < 0.001) and femoral head–neck ratio (p = 0.024). Radiological evidence of symptomatic FAI was not uncommon in these Japanese patients.

Cite this article: Bone Joint J 2013;96-B:172–6.

For the treatment of ununited fractures, we developed a system of delivering magnetic labelled mesenchymal stromal cells (MSCs) using an extracorporeal magnetic device. In this study, we transplanted ferucarbotran-labelled and luciferase-positive bone marrow-derived MSCs into a non-healing femoral fracture rat model in the presence of a magnetic field. The biological fate of the transplanted MSCs was observed using luciferase-based bioluminescence imaging and we found that the number of MSC derived photons increased from day one to day three and thereafter decreased over time. The magnetic cell delivery system induced the accumulation of photons at the fracture site, while also retaining higher photon intensity from day three to week four. Furthermore, radiological and histological findings suggested improved callus formation and endochondral ossification. We therefore believe that this delivery system may be a promising option for bone regeneration.

Introduction

Since 2005, we have performed implantation of bone marrow-derived mononuclear cells for osteonecrosis of the femoral head in order to improve vascularization and bone repair. This study focused on early bone repair of osteonecrosis of the femoral head after transplantation of bone marrow-derived mononuclear cells (BMMNC).

We examined whether enamel matrix derivative (EMD) could improve healing of the tendon–bone interface following reconstruction of the anterior cruciate ligament (ACL) using a hamstring tendon in a rat model. ACL reconstruction was performed in both knees of 30 Sprague-Dawley rats using the flexor digitorum tendon. The effect of commercially available EMD (EMDOGAIN), a preparation of matrix proteins from developing porcine teeth, was evaluated. In the left knee joint the space around the tendon–bone interface was filled with 40 µl of EMD mixed with propylene glycol alginate (PGA). In the right knee joint PGA alone was used. The ligament reconstructions were evaluated histologically and biomechanically at four, eight and 12 weeks (n = 5 at each time point). At eight weeks, EMD had induced a significant increase in collagen fibres connecting to bone at the tendon–bone interface (p = 0.047), whereas the control group had few fibres and the tendon–bone interface was composed of cellular and vascular fibrous tissues. At both eight and 12 weeks, the mean load to failure in the treated specimens was higher than in the controls (p = 0.009). EMD improved histological tendon–bone healing at eight weeks and biomechanical healing at both eight and 12 weeks. EMD might therefore have a human application to enhance tendon–bone repair in ACL reconstruction.

Background: A retroverted acetabulum has been hypothesized as a cause of osteoarthritis. This study was performed to evaluate whether radiographical cross-over sign influence the painful femoro-acetabular impingement or the radiographical progression of osteoarhritis after rotational acetabular osteotomy (RAO) for dysplastic hip.

Methods: Between 1987 and 1999, 104 patients (115 hips) who had pre- or early stage osteoarthritis of the hip due to dysplasia underwent a RAO. There were 99 women and five men; their mean age at the time of surgery was 34.7 years. The mean follow-up period was 13 years. Clinical follow-up was performed with use of the system of Merle d’Aubigne and the impingement sign was evaluated. Radiographical analyses included measurements of the center-edge angle, acetabular roof angle, head lateralization index, joint congruency, cross-over sign, posterior wall sign, acetabular index of depth to width, pistol grip deformity and femoral head-femoral neck ratio.

Results: The mean clinical score improved significantly from 14.6 preoperatively to 17.0 at follow-up. The impingement sign at the follow-up was observed in 14 hips (12.2%). The center-edge angle improved significantly from mean −0.6 degrees to a postoperative mean of 34 degrees. The acetabular roof angle improved from 30 degrees to 2.2 degrees, and head lateralization index from 0.64 to 0.60. The cross-over sign was observed in 8 hips (7.0%) preoperatively and in 49 hips (42.6%) postoperatively. The posterior wall sign was observed in 70 hips (60.9%) preoperatively and observed in 73 hips (63.5%) postoperatively. The mean preoperative acetabular index of depth to width was 35.5% and the mean preoperative femoral head to femoral neck ratio was 1.49. The pistol grip deformity was observed in only 4 hips (3.5%) preoperatively. The impingement sign after the RAO was positive significantly in the postoperative cross-over sign positive hips (p=0.0074). Radiographical progression of osteoarthritis was observed in 11 hips (cross over sign positive; 7 hips, cross over sign negative; 4 hips). The Kaplan-Meier survivorship analysis predicted a survival rate of 84.6 % at 15 years. The only factors significantly associated with radiographic signs of progression of osteoarthritis after RAO were fair (rather than excellent and good) postoperative joint congruency (p< 0.0001) and age at surgery (p=0.0042). Presence of postoperative cross-over sign had no effect on the outcome (p=0.2073).

Conclusions: Although there was no significant radiographical progression of osteoarthritis despite a significant retroversion in most cases, the goal of RAO should be a correct alignment of the acetabulum including a correct version with a negative cross-over sign.

The transfer of part of the ulnar nerve to the musculocutaneous nerve, first described by Oberlin, can restore flexion of the elbow following brachial plexus injury. In this study we evaluated the additional benefits and effectiveness of quantitative electrodiagnosis to select a donor fascicle. Eight patients who had undergone transfer of a simple fascicle of the ulnar nerve to the motor branch of the musculocutaneous nerve were evaluated. In two early patients electrodiagnosis had not been used. In the remaining six patients, however, all fascicles of the ulnar nerve were separated and electrodiagnosis was performed after stimulation with a commercially available electromyographic system. In these procedures, recording electrodes were placed in flexor carpi ulnaris and the first dorsal interosseous. A single fascicle in the flexor carpi ulnaris in which a high amplitude had been recorded was selected as a donor and transferred to the musculocutaneous nerve. In the two patients who had not undergone electrodiagnosis, the recovery of biceps proved insufficient for normal use. Conversely, in the six patients in whom quantitative electrodiagnosis was used, elbow flexion recovered to an M4 level.

Quantitative intra-operative electrodiagnosis is an effective method of selecting a favourable donor fascicle during the Oberlin procedure. Moreover, fascicles showing a high-amplitude in reading flexor carpi ulnaris are donor nerves that can restore normal elbow flexion without intrinsic loss.

We used interconnected porous calcium hydroxyapatite ceramic to bridge a rabbit ulnar defect. Two weeks after inducing the defect we percutaneously injected rabbit bone marrow-derived mesenchymal stromal cells labelled with ferumoxide. The contribution of an external magnetic targeting system to attract these cells into the ceramic and their effect on subsequent bone formation were evaluated.

This technique significantly facilitated the infiltration of ferumoxide-labelled cells into ceramic and significantly contributed to the enhancement of bone formation even in the chronic phase. As such, it is potentially of clinical use to treat fractures, bone defects, delayed union and nonunion.

The purpose of this study was to elucidate the hemostatic effects of tranexamic acid (TA) in patients undergoing total knee arthroplasty (TKA) performed with different three methods.

The subjects were 89 patients (10 males, 79 females; mean age at surgery 74 years old) who underwent TKA for osteoarthritic knees in our department between April 2006 and October 2007. A cemented prosthesis (NexGen LPS flex, Zimmer) was used in all cases. The subjects were divided into three groups; Group A (n=39), in whom intravenous administration of TA (1 000 mg) 15 minutes before tourniquet release and a drain-clamping method [DC; joint filled with 50 ml of fluid that contained TA (1 000 mg, 10 ml) and 40 ml of physiological saline just after surgery] were performed, as reported by Prof. Otani (Keio Univ., Tokyo, Japan) in 2005; Group B (n=20), who had the same protocol as Group A, except that the DC Joint was filled with a total of 50 ml physiological saline alone; and group C (n=30), who received DC alone with 50 ml of physiological saline and no intravenous administration of TA. The parameters evaluated were the amounts of intra-operative bleeding, bleeding after 24 hours, total bleeding (intra- and post-operative), and changes in Hb levels between before surgery and 1 week after surgery. Statistical analyses were performed using a Mann-Whitney U-test, with P-values greater than 0.05 considered to be significant.

No differences were observed in the amount of bleeding during the TKA among the groups. In contrast, bleeding at 24 hours after surgery and total amounts of bleeding were significantly lower in Group A (281 and 695ml, respectively) as compared to Group B (337 and 868 ml, respectively) and Group C (650 and 1043 ml, respectively) (p< 0.01). In addition, Hb levels at 1 week after surgery were reduced by 1.8 g/dl in Group A, as compared to 2.3 and 3.0 g/dl in Groups B and C, respectively, demonstrating a significantly lower amount of reduction in Group A (p< 0.01).

The effect of TA for reducing blood loss in TKA is widely recognized. In the present study, concomitant use of an intravenous administration and infiltration into the joint (via DC) significantly reduced blood loss during and after TKA. Furthermore, allogenic blood transfusion could be avoided in all patients (Group A) who underwent that protocol. In our study, even when given intra-operatively, such as intravenous administration and infiltration, there were no complications. Nevertheless, when used during the post-operative course, careful attention should be paid to prevent such problems. In order to reduce blood loss during and after TKA, it is important to elucidate the optimal conditions, volume, and timing of administration of TA in future studies.

This study was conducted to investigate the cases which were obliged to receive revision surgery within the first 5 years after primary Total Knee Arthroplasty (TKA).

The subjects of this study were 15 patients (5 males & 10 females, mean age at revision 72 years) who had undertaken revision surgery within 5 years since 1996. Intervals between primary and revision TKA averaged 29.8 months. Prosthesis used for primary TKA was as follows; 11 Zimmer NexGen LPS-flex fixed bearing, 2 mobile bearing, 2 CR type.

Revised components, cause of revision, JOA score as clinical results and FTA as radiographic evaluation were examined.

Revised parts were as follows;

All components: 2,

Stemmed Femoral components were used in 6 out of 8 knees, stemmed Tibial components in 9 out of 11 knees.

The causes of revision were as follows;

infection: 1,

JOA scores improved from 45 points to 78 points, and FTA proved to be 176 deg., postoperatively.

Primary TKA remains one of the most successful orthopedic procedures. Survivorship was generally reported over 15 years in the previous article. However, there are some cases in which revision TKA is necessary by some causes. There seems to be various types of causes for revisions, such as loosening, inadequate position, abrasion of components and others. Though loosening of components due to traumatic cause was inevitable, other causes, such as inadequate position of component, imbalanced soft tissues and infection, which depend on our technique, should be cared during and after surgery. From our study, except for 7 (2 trauma, 5 unknown) out of 15 knees, almost half of revision TKA (8 knees) might be due to technical demand. As for surgical techniques, in the case of poor bony quality, we routinely use stemmed components and should try not to impact strongly on setting component to prevent from sinking. In the case of non-traumatic cause, 3 out of 12, though the position of tibial component was acceptable, tibial component sunk because of bony weakness and/or imbalanced soft tissues resulting pain.

Adequate position and balance of components should be achieved during primary TKA. In our department, we are trying to revise and routinely use stemmed components as soon as possible, when loosening of component is confirmed. Metal augmentation, if necessary, is mainly used for bone defect to do early rehabilitation.

We concluded that adequate position of components and soft tissue balance was very important at the time of primary TKA. Clinical results of revision TKA were almost equal to those of primary TKA, however, long term follow-up will be needed.

We have investigated the effectiveness of the transplantation of bone-marrow-derived mononuclear cells (BMMNCs) with interconnected porous calcium hydroxyapatite (IP-CHA) on early bone repair for osteonecrosis of the femoral head. We studied 22 patients (30 hips) who had osteonecrosis with a minimum follow-up of one year after implantation of BMMNCs. The mean age at surgery was 41 years (18 to 64) and the mean period of follow-up was 29 months (19 to 48). In a control group, cell-free IP-CHA was implanted into a further eight patients (9 hips) with osteonecrosis of the femoral head and the outcomes were compared.

A reduction in the size of the osteonecrotic lesion was observed subsequent to hypertrophy of the bone in the transition zone in the BMMNC group. In three patients in the treatment group progression to extensive collapse was detected. In the control group subtle bone hypertrophy was observed, but severe collapse of the femoral head occurred in six of eight hips.

In this limited study the implantation of BMMNCs and IP-CHA appears to confer benefit in the repair of osteonecrosis and in the prevention of collapse.

This study was conducted to investigate the correlation between intra-operative Flexion Balance (IFB) and post-operative Flexion instability in Posterior-Stabilized Total Knee Arthroplasty (TKA).

Eighty-three knees (4 males and 79 females, average 74 y/o) with primary TKA (Zimmer NexGen LPS flex fixed-bearing) for varus osteoarthritis in our hospital between January 2006 and December 2007, were included in this study. After bone-cutting independently and balancing manually, Extension Balance (EB) and IFB were measured with seesaw type tensor. Post-operative Flexion Balance (PFB) was evaluated as post-operative instability with Kanekasu’s Epicondylar view at the least more than 6 months postoperatively. Varus inclination (lateral joint opening) was indicated as plus. In addition, pre-operative standing FTA (femorotibial angle), the change of FB (CFB=PFB-IFB) and True Correction Angle (TCA=FTA-174-EB), we had defined, were calculated. The TCA was hypothesized to mean the extent of medial soft tissue release. With these data, the correlation between IFB and PFB, CFB and TCA were analyzed. Of these, furthermore, in the well-balanced knees (IFB ≥ ±2°), same analyses were done. Statistical analysis was performed with StatView software.

Each data (n=83) in all subjects was as follows (Mean ± SD, degrees.); EB: 2.74 ±2.74, IFB: 1.61 ±3.67, PFB: 1.73 ±2.66, CFB: 0.01 ±4.25, FTA: 185.3 ±6.7, TCA: 8.65 ±6.52, respectively. Though there was no correlation between IFB and PFB (r=−0.09, p=0.57), CFB was correlated with TCA (r=0.40, p< 0.01).

Each data in the well-balanced knees (n=43) was as follows, EB: 3.09 ±2.71, IFB: 0.70 ±1.30, PFB: 1.22 ±2.52, CFB: 0.57 ±2.3, FTA: 185.5 ±6.5, TCA: 8.42 ±6.09, respectively. There was a correlation between IFB and PFB (r=0.41, p< 0.01), however, FBC was not correlated with TCA (r=−0.26, p=0.10).

Same rectangular balance has been thought to be one the most important factors to obtain the good postoperative stability in TKA. For correcting alignment of lower extremity, medial or posteromedial release are generally needed to perform mainly in extended knee. Even if well-balanced EB was achieved, IFB does not necessarily prove to be well, rather than sparse. This might be because intra-operative balance was not measured under physiological condition, especially after wide posteromedial release. Soft tissues released for balancing would be repaired and shortened over time, so it seems to be natural that intra-operative balance would change. We have reported that EB was correlated with post-operative instability in the previous congress (ISTA 2006). However, it remains unknown as for FB. Our study demonstrated that CFB increased in accordance with the extent of soft tissue release (TCA), and that IFB was correlated with PFB only in the well balanced knees. This means that the measurement of IFB was not useful for predicting PFB in the imbalanced knees. That’s why we should achieve adequate balance & gap during operation and should recognize that FB was influenced by various factors, not only soft tissues but also rotation and inclination of components. In the future, how to measure IFB, including tensor and measurement condition, should be considered and established to predict knee balancing for good clinical results.

We evaluated the histological changes before and after fixation in ten knees of ten patients with osteochondritis dissecans who had undergone fixation of the unstable lesions. There were seven males and three females with a mean age of 15 years (11 to 22). The procedure was performed either using bio-absorbable pins only or in combination with an autologous osteochondral plug. A needle biopsy was done at the time of fixation and at the time of a second-look arthroscopy at a mean of 7.8 months (6 to 9) after surgery.

The biopsy specimens at the second-look arthroscopy showed significant improvement in the histological grading score compared with the pre-fixation scores (p < 0.01). In the specimens at the second-look arthroscopy, the extracellular matrix was stained more densely than at the time of fixation, especially in the middle to deep layers of the articular cartilage.

Our findings show that articular cartilage regenerates after fixation of an unstable lesion in osteochondritis dissecans.

We investigated the use of hypoxia-inducible factor (HIF) proteins as prognostic markers in chondrosarcoma and the relationship of HIF to the biological characteristics of cartilage tumours. The expression of HIF-1α, HIF-2α, proliferating cell nuclear antigen (PCNA) and microvessel density (MVD) were measured immunohistochemically in 29 specimens of cartilage tumour.

There was no HIF-1α and HIF-2α staining in any of the nine benign cartilage tumours. In 20 specimens of chondrosarcoma, the rate of HIF-1α and HIF-2α expression was 40% and 25%, respectively. The tumour size (≥ 8 cm), histological grade (grade 2 and grade 3) surgical margin (marginal and intralesional) and HIF-1α expression (positive) correlated significantly with a shorter disease-free survival. There was a significant association between HIF-1α and the MVD and a strong trend towards a correlation between HIF-1α and the PCNA index or histological grade.

Our findings suggest that HIF-1α protein may be a useful objective marker in the assessment of the prognosis in chondrosarcoma, since it plays an important role in tumour angiogenesis and cell proliferation.

Bone marrow mesenchymal stromal cells were aspirated from immature male green fluorescent protein transgenic rats and cultured in a monolayer. Four weeks after the creation of the osteochondral defect, the rats were divided into three groups of 18: the control group, treated with an intra-articular injection of phosphate-buffered saline only; the drilling group, treated with an intra-articular injection of phosphate-buffered saline with a bone marrow-stimulating procedure; and the bone marrow mesenchymal stromal cells group, treated with an intra-articular injection of bone marrow mesenchymal stromal cells plus a bone marrow-stimulating procedure. The rats were then killed at 4, 8 and 12 weeks after treatment and examined.

The histological scores were significantly better in the bone marrow mesenchymal stromal cells group than in the control and drilling groups at all time points (p < 0.05). The fluorescence of the green fluorescent protein-positive cells could be observed in specimens four weeks after treatment.

We have investigated the changes in anterior laxity of the knee in response to direct electrical stimulation of eight normal and 45 reconstructed anterior cruciate ligaments (ACLs). In the latter, the mean time from reconstruction was 26.7 months (24 to 32). The ACL was stimulated electrically using a bipolar electrode probe during arthroscopy. Anterior laxity was examined with the knee flexed at 20° under a force of 134 N applied anteriorly to the tibia using the KT-2000 knee arthrometer before, during and after electrical stimulation.

Anterior tibial translation in eight normal and 17 ACL-reconstructed knees was significantly decreased during stimulation, compared with that before stimulation. In 28 knees with reconstruction of the ACL, in 22 of which the grafts were found to have detectable somatosensory evoked potentials during stimulation, anterior tibial translation was not decreased. These findings suggest that the ACL-hamstring reflex arc in normal knees may contribute to the functional stability and that this may not be fully restored after some reconstructions of the ACL.

Introduction. Dysplasia of the hip is the commonest cause of secondary osteoarthritis. One treatment is periacetabular osteotomy such as rotational acetabular osteotomy(RAO). These procedures have generally produced satisfactory mid- and long-term results, but unfavorable results have been reported in a few cases. We evaluated the 10-year results to determine the factors of prognostic importance.

Methods. We studied 91 patients (100 hips) at prearthritis or early stage. The mean age at surgery was 36 years (13 – 58) and mean follow-up period was 11 years (8–16). 81 were women (89 hips) and 10 were men (11 hips). Clinical follow-up was done using the system of Merle d’Aubigne. Radiologically, CE angle, AC angle and head lateralization index (HLI) were measured prior to surgery, 3 months postoperatively and at follow-up. Postoperative joint congruencies were classified into four grades.

Results. The mean clinical score significantly increased from 14 to 17 and only in 4 cases the mean score decreased. CE angle, AC angle, and HLI significantly improved after surgery. Progression of osteoarthritis was radiologically observed at follow-up in 7 hips. Kaplan-Meier survivorship analysis predicted the rate of prevention of osteoarthritic progression at 10 years as 93%. Parametric survivorship analysis using the Cox hazards model indicated that postoperative joint congruency is a risk factor for progression of osteoarthritis.

Discussion/Conclusion. Our findings have suggested that RAO is valuable in preventing osteoarthritic progression for at least 10 years. If risk factors can be reduced, a longer operative effect may be expected.

Acetabular dysplasia was produced in 24 immature white rabbits. A rotational acetabular osteotomy was then carried out and radiological and histological studies of the articular cartilage were made.

In the hips which did not undergo osteotomy, radiographs at 26 weeks showed that residual subluxation remained and arthritic changes such as narrowing of the joint space or dislocation were still seen. However, in the operated group there was a remarkable increase in cover, but arthritic changes were not observed. After 24 weeks, the Mankin grading score in the operated group was significantly lower than that in the non-operated group. The latter hips showed an irregular surface of the cartilage, exfoliation and proliferation of synovial tissue. In those undergoing osteotomy, primary cloning of chondrocytes or hypercellularity was seen and at 24 weeks after operation and metaplasia of the cartilage in the fibrous tissue was observed in the boundary between the medial area of the acetabulum and the acetabular fossa.

A total of 108 patients with unilateral instability of the knee, associated with rupture of the anterior cruciate ligament, was prospectively randomised for arthroscopic single- or double-bundle reconstruction of the ligament using hamstring tendons. The same postoperative rehabilitation protocol was used for all. The patients were followed up for a mean of 32 months (24 to 36). We measured the anterior laxity and joint position sense at different angles of flexion of the knee to determine whether both bundles in the double-bundle reconstruction contributed to the stability of the joint and proprioception.

No significant difference was found between the two groups with regard to anterior laxity measured by the KT-2000 arthrometer with the knee at 20° or 70° flexion nor with regard to proprioception. A notchplasty was required less often in the double- compared with the single-bundle reconstruction.

We did not find any advantage in a double-bundle as opposed to a single-bundle reconstruction in terms of stability or proprioception.

We investigated the clinical outcome of a reconstructive procedure of the medial patellofemoral ligament for the treatment of habitual or recurrent dislocation of the patella in four children (6 knees), with a minimum follow-up of four years. The technique involves transfer of the tendon of semitendinosus to the patella using the posterior one-third of the femoral insertion of the medial collateral ligament as a pulley.

There was no recurrence of dislocation after surgery. The mean Kujala score at follow-up was 96.3 points. Radiological assessment showed that the congruence angle, the tilt angle and the lateral shift radio were restored to normal. The lateral and medial stress shift ratios and the Insall-Salvati ratio remained abnormal.

We conclude that this technique can be recommended for the treatment of habitual or recurrent patellar dislocation in children, although hypermobility and patella alta are not fully corrected.

In 52 patients we compared the accuracy of standard anteroposterior (AP) radiography, mortise radiography and MRI with arthroscopy of the ankle for the diagnosis of a tear of the tibiofibular syndesmosis. In comparison with arthroscopy, the sensitivity, specificity and accuracy were 44.1%, 100% and 63.5% for standard AP radiography and 58.3%, 100% and 71.2% for mortise radiography. For MRI they were 100%, 93.1% and 96.2% for a tear of the anterior inferior tibiofibular ligament and 100%, 100% and 100% for a tear of the posterior inferior tibiofibular ligament. Standard AP and mortise radiography did not always provide a correct diagnosis. MRI was useful although there were two-false positive cases. We suggest that arthroscopy of the ankle is indispensable for the accurate diagnosis of a tear of the tibiofibular syndesmosis.

Introduction: Accelerated rehabilitation programs following ACL reconstruction require adequate fixation strength. Staple fixation of grafts outside the tibial tunnel has been shown to have fixation strength comparable to interference screws. The use of bioresorbable polymer implants has potentially significant advantages especially if revision is required. The purpose of this study was to evaluate a new bioresorbable fixation staple using an ovine model.

Materials and Methods: Forty-eight mature sheep underwent unilateral cranial cruciate ligament (CrCl) reconstruction. The reconstruction comprised a loop of superficial digital flexor tendon (autograft) joined to a prosthetic ligament (LK-15). Femoral fixation was by endobutton. Tibial fixation of the LK-15 was with either a new Poly-L-lactic acid (PLLA) staple (Zimmer Japan/Gunze Ltd.) or a Cobalt-chrome (CoCr) staple. Biomechanical and histological responses were evaluated at 0, 6, 12 and 24 weeks.

Results: At all times post-reconstruction there were no significant differences between staple types for construct strength or stiffness (p> 0.05). The staple was not the site of reconstruction failure, and there were no adverse tissue reactions, for either staple type. Fibrous tissue was more often found at the interface of the CoCr staple.

Conclusions: The PLLA staple performed biomechanically as well as the metal staple for tibial fixation of cruciate ligament reconstructions. There were no significant observable adverse histological responses over the time intervals examined.

We have determined whether somatosensory evoked potentials (SEPs) were detectable after direct mechanical stimulation of normal, injured and reconstructed anterior cruciate ligaments (ACLs) during arthroscopy. We investigated the position sense of the knee before and after reconstruction, and correlated the SEP with instability.

Reproducible SEPs were detected in all 19 normal ACLs and in 36 of 38 ACLs reconstructed during a period of 13 months. Of the 45 injured ACLs, reproducible SEPs were detected in 26. The mean difference in anterior displacement in the SEP-positive group of the injured ACL group was significantly lower than that in the SEP-negative group. In the reconstructed group, the postoperative position sense was significantly better than the preoperative position sense. Our results indicate not only that sensory reinnervation occurs in the reconstructed ACL, but also that the response to mechanical loads can be restored, and is strongly related to improvement in position sense.

We investigated the clinical, arthroscopic and biomechanical outcome of transplanting autologous chondrocytes, cultured in atelocollagen gel, for the treatment of full-thickness defects of cartilage in 28 knees (26 patients) over a minimum period of 25 months. Transplantation eliminated locking of the knee and reduced pain and swelling in all patients. The mean Lysholm score improved significantly. Arthroscopic assessment indicated that 26 knees (93%) had a good or excellent outcome. There were few adverse features, except for marked hypertrophy of the graft in three knees, partial detachment of the periosteum in three and partial ossification of the graft in one. Biomechanical tests revealed that the transplants had acquired a hardness similar to that of the surrounding cartilage. We conclude that transplanting chondrocytes in a newly-formed matrix of atelocollagen gel can promote restoration of the articular cartilage of the knee.

For the purpose of investigating the effect of an insole with a lateral wedge, we studied 30 patients (31 knees) aged from 46 to 78 years with idiopathic osteonecrosis of the knee for at least three years. The 18 knees treated with an insole (group I) were matched by age, gender, obesity index, area of lesion, femorotibial angle, stage, and clinical evaluation with 13 treated conservatively without an insole (group II).

The clinical results, as rated by a knee score, improved significantly more in group I than in group II. Radiologically, the necrotic area and ratio decreased in group I, whereas in group II they increased. In advanced cases, with stage 4 or a femorotibial angle of more than 180°, the use of an insole did not improve the clinical or radiological findings. The insole is a valuable method of conservative treatment for the early stages of osteonecrosis of the medial femoral condyle.

We examined whether somatosensory evoked potentials (SEPs) were detectable after direct electrical stimulation of injured, reconstructed and normal anterior cruciate ligaments (ACL) during arthroscopy under general anaesthesia. We investigated the position sense of the knee before and after reconstruction and the correlation between the SEP and instability.

We found detectable SEPs in all ligaments which had been reconstructed with autogenous semitendinosus and gracilis tendons over the past 18 months as well as in all cases of the normal group. The SEP was detectable in only 15 out of 32 cases in the injured group, although the voltages in the injured group were significantly lower than those of the controls. This was not the case in the reconstructed group. The postoperative position sense in 17 knees improved significantly, but there was no correlation between it and the voltage. The voltage of stable knees was significantly higher than that of the unstable joints. Our findings showed that sensory reinnervation occurred in the reconstructed human ACL and was closely related to the function of the knee.