Coronal plane fractures of the posterior femoral condyle, also known as Hoffa fractures, are rare. Lateral fractures are three times more common than medial fractures, although the reason for this is not clear. The exact mechanism of injury is likely to be a vertical shear force on the posterior femoral condyle with varying degrees of knee flexion. These fractures are commonly associated with high-energy trauma and are a diagnostic and surgical challenge. Hoffa fractures are often associated with inter- or supracondylar distal femoral fractures and CT scans are useful in delineating the coronal shear component, which can easily be missed. There are few recommendations in the literature regarding the surgical approach and methods of fixation that may be used for this injury. Non-operative treatment has been associated with poor outcomes. The goals of treatment are anatomical reduction of the articular surface with rigid, stable fixation to allow early mobilisation in order to restore function. A surgical approach that allows access to the posterior aspect of the femoral condyle is described and the use of postero-anterior lag screws with or without an additional buttress plate for fixation of these difficult fractures. Cite this article: Bone Joint J 2013;95-B:1165–71

Aims. Dual plating of distal femoral fractures with medial and lateral implants has been performed to improve construct mechanics and alignment, in cases where isolated lateral plating would be insufficient. This may potentially compromise vascularity, paradoxically impairing healing. This study investigates effects of single versus dual plating on distal femoral vascularity. Methods. A total of eight cadaveric lower limb pairs were arbitrarily assigned to either 1) isolated lateral plating, or 2) lateral and medial plating of the distal femur, with four specimens per group. Contralateral limbs served as matched controls. Pre- and post-contrast MRI was performed to quantify signal intensity enhancement in the distal femur. Further evaluation of intraosseous vascularity was done with barium sulphate infusion with CT scan imaging. Specimens were then injected with latex medium and dissection was completed to assess extraosseous vasculature. Results. Quantitative MRI revealed a mean reduction of 21.2% (SD 1.3%) of arterial contribution in the lateral plating group and 25.4% (SD 3.2%) in the dual plating group (p = 0.051); representing a mean decrease in arterial contribution of 4.2%. The only significant difference found between both experimental groups was regionally, at the lateral aspect of the distal femur with a mean drop in arterial contribution in the lateral plating group of 18.9% (SD 2.6%) versus 24.0% (SD 3.2%) in the dual plating group (p = 0.048), representing a mean decrease in arterial contribution of 5.1%. Gross dissection revealed complete destruction of periosteal vessels underneath either medial or lateral plates in both groups. The network of genicular branches contributing to the posterior and distal femoral condyles was preserved in all specimens. A medial vascular pedicle was found dividing from the superficial femoral artery at a mean 12.7 cm (SD 1.7) proximal to the medial epicondyle and was undisrupted in the dual plating group. Conclusion. Lateral locking-plate application resulted in mean 21.2% reduction in distal femur vascularity. Addition of medial plates did not further markedly decrease vascularity. As such, the majority of the vascular insult occurred with lateral plating alone. Supplemental medially based fixation did not lead to marked devascularization of the distal femur, and should therefore be considered in the setting of comminution and poor bone stock in distal femoral fractures. Further clinical research is required to confirm the results of this study. Cite this article: Bone Joint J 2020;102-B(4):530–538

Single focal grade IV cartilage lesion in the knee has a poor healing capacity. Instead these lesions often progress to severe and generalized osteoarthritis that may result in total knee replacement. Current treatment modalities aim at biological repair and, although theoretically appealing, the newly formed tissue is at the best cartilage-like, often fibrous or fibrocartilaginous. This at the expense of sophisticated laboratory resources, delicate surgery and strict compliance from patients. An alternative may be small implants of biomaterial inserted to replace the damaged cartilage. We investigated the response of the opposing tibia cartilage to a metallic implant inserted at different depth into the surrounding cartilage level. Methods. The medial femoral condyle of both knees of 12 sheep, 70–90kg, 2 year of age and from the same breeder, was operated. A metallic implant with an articulating surface of 316L stainless steel, diameter of 7mm, HA plasma sprayed press-fit peg and a tailored radius and contour to the sheep femoral condyle was placed at the most weight-bearing position. The level of the implant was aimed flush, 0,3 and 0,8 mm below surrounding cartilage. The animals were stabled indoors, allowed to move freely and euthanized after 6 and 12 weeks. Postoperatively the knees were high resolution photographed for macroscopic evaluation. The position and depth of the implant were analysed using a laser scan device. Tibial and femoral condyles specimen were decalcified and slices were prepared for microscopic evaluation. Implant position and cartilage damage was assessed from two independent observers using a macroscopic ICRS score and a modified histologic score according to Mankin. Results. 22 tibia condyles showed a variety of cartilage damage ranging from severe damage down to subchondral bone to an almost pristine condition. There was a strong correlation between implant position and damage to opposing cartilage surface. Mankin score correlated significantly with implant position (p<0.001 regression analysis, r. 2. =.45) as did the ICRS score (p<0.001, regression analysis, r. 2. =.67). Implants sitting proud were associated with poor Mankin score. There was no difference between 6-week and 3-months knees. Conclusion. By precise postoperative measurement we have shown that significant imprecision occur; this has never before been studied. We found a distinct correlation between implant position and cartilage damage. These results suggest that further studies of metallic implants, inserted into cartilage defects with the utmost precision regarding the surrounding cartilage, may be warranted

Chondral injuries of the knee are extremely common and present a unique therapeutic challenge due to the poor intrinsic healing of articular cartilage. These injuries can lead to significant functional impairment. There are several treatment modalities for articular osteochondral defects, one of which is autologous chondrocyte implantation. Our study evaluates the mid to long term functional outcomes in a cohort of 828 patients who have undergone an autologous chondrocyte implantation procedure (either ACI or MACI), identifying retrospectively factors that may influence their outcome. The influence of factors including age, sex, presence of osteoarthritis and size and site of lesion have been assessed individually and with multivariate analysis. All patients were assessed using the Bentley Functional Score, Visual Analogue Score and the Cincinnati Functional Score. Assessment were performed pre-operatively and of their status in 2010. The majority of patients had several interim scores performed at varying intervals. The longest follow-up was 12 years (range 24 to 153 months) with a mean age of 34 years at time of procedure. The mean defect size was 486 mm2 (range 64 to 2075 mm2). The distribution of lesions was 51% Medial Femoral Condyle, 12.5% Lateral Femoral Condyle, 18% Patella (single facet), 5% Patella (Multifacet) and 6% Trochlea. 4% had cartilage transplant to multiple sites. 30% failed following this procedure at a mean time of 72 months. 52% patients stated a marked improvement in their functional outcomes within the first two years. 49% stated an excellent result following their procedure. High failure rate was noted in those with previous cartilage regenerative procedures, transplants occurring on the patella, particularly if involving multifacets. Multiple site cartilage transplantation was also associated with a high failure rate. Autologous chondrocyte implantation is an effective method of decreasing pain and increasing function, however patient selection plays clear role in the success of such procedure

Purpose. to evaluate the kinematics of a knee with a polyurethane meniscal scaffold for partial meniscus defect substitution during flexion under weightbearing conditions in an upright MRI. In addition, radial displacement and the surface of the scaffold was compared to the normal meniscus. Materials and Methods. One cadaver with a normal lateral meniscus and medial scaffold in the left knee and with a normal medial meniscus and lateral scaffold in the right knee. The scaffolds were implanted to substitute a 3 cm meniscus defect in the posterior horn. The cadaver was scanned in an 0,7T open MRI with a range of motion from 0-30-60-90 to hyperflexion. Kinematics were evaluated on sagittal images by the following two parameters: the position of the femoral condyle, identified by the centre of its posterior circular surface, which is named the flexion facet centre (FFC), and the point of closest approximation between the femoral and tibial subchondral plates, the contact point (CP). Both were identified in relation to the posterior tibial cortex. The displacement, measured on coronal images, is defined as the distance between the tibial plateau and the outer edge of the meniscus. The surface was also measured on coronal slices and contains the triangular surface of the meniscus. Results. Medially from 0 degrees to hyperflexion the FFC does not move anteroposteriorly. Laterally the FFC moves 12 mm backwards. The CP moves 15 mm backwards both lateral and medial. The lateral femoral condyle does roll-back with flexion but the medial does not, so the femur rotates externally around a medial centre. By contrast, both medial and lateral contact points move back, roughly in parallel, from 0 degrees to hyperflexion. The kinematics of the involved compartment is not influenced by the presence of the scaffold compared to the controlateral normal compartment. The radial displacement remains stable during full flexion: both the normal and scaffold meniscus have no different (p > 0,05) position. Both for the normal and the scaffold meniscus there is no difference (p > 0,05) in surface; there is no compression of the meniscus during flexion. Conclusion. The polyurethane implant, indicated for partial meniscus defect substitution, has no effect on the normal kinematics of the knee. Additionally, the degree of flexion has no effect on the external displacement, the surface and compressibility of both the implanted scaffold and the meniscus

Background. Adequate rotation of femoral component in total knee arthroplasty(TKR) is mandatory for preventing numerous adverse sequelae. The transepicondylar axis has been a well-accepted reference for femoral component rotation in the measured resection technique. In this technique, measured resection is performed referenced off the tibial cut - perpendicular to the tibial mechanical axis with the knee in 90 ° of flexion. However, to the best of our knowledge, it is not known whether this technique apply well to a knee with tibia vara. This study evaluates the reliability of the transepicondylar axis as a rotational landmark in knees with tibia vara. Methods. We selected 101 osteoarthritis knees in 84 symptomatic patients(mean age: 69.24 ± 5.68) with proximal tibia vara (Group A). Group A was compared with 150 osteoarthritic knees without tibia vara in 122 symptomatic patients (mean age: 69.51 ± 6.01) (Group B). The guide line for selection of all these knees were based on the degree of tibia vara angle (TVA) which was formed by line perpendicular to epiphysis and by anatomical axis of the tibia - all measured in radiographs of the entire lower limb. Magnetic resonance imaging (MRI) axial images with most prominent part of both femoral condyles were used for measurement of transepicondylar axis(TE), anteroposterior axis(AP) and posterior condylar axis(PC). Results. The mean TVA of group A was 8.94° ± 3.11 and group B was 1.24° ± 0.85. The TE line in Group A showed 6.09 ° ± 1.43 of external rotation, relative to PC. This did not show statistical difference compared with 5.95 ° ± 1.58 in Group B (p=0.4717). The AP line in Group A showed 6.06 ° ± 1.93 of external rotation, relative to the line perpendicular to PC. This was statistically significant when compared to 5.44 ° ± 2.13 in Group B (p=0.020). Conclusion. There is no difference between knees without tibia vara compared those with tibia vara with regards to transepicondylar axis. In addition, both groups have almost identical external rotation of approximately 6 °. The AP axis was only approximately 0.5 ° difference between the two groups. The distal femoral geometry was not affected by tibia vara deformity, that is, there were no hypoplastic or hyperplastic deformities of medial femoral condyle in osteoarthritic knees with tibia vara. The use of transepicondylar axes in determining femoral rotation may produce flexion asymmetry in knees with proximal tibia vara. So, It should be pointed out that more attention should be paid on femoral component rotation and flexion gap balancing in knees with proximal tibial vara

Background. Severe infantile Blount's disease can result in a multiplanar deformity of the proximal tibia with both intra-articular and metaphyseal components. Correction can represent a significant surgical challenge. We describe our results using the Taylor spatial frame for acute tibial hemiplateau elevation combined with gradual metaphyseal correction in patients with severe infantile blounts with an associated physeal bony bar. Methods. Eight patients (10 knees) underwent tibial hemiplateau elevation and metaphyseal correction with use of the Taylor Spatial Frame between 2012–2016. We undertook a retrospective case note and radiographic review of all patients to assess clinical and radiographic outcomes. Mean age at the time of surgery of was 11.7 years and mean length of follow up was 16.8 months. Results. At time of latest follow up all patients reported no hip, knee or ankle pain. All knees were clinically stable without lateral thrust during gait. Improvement in radiographic parameters was seen in all patients. The mean tibiofemoral angle improved from −28.3 to 5.9 degrees post operatively. The angle between femoral condyles and the tibial shaft improved from a mean of 56.3 degrees to 90.3 degrees. The joint depression angle was also seen to improve from mean 47.4 degrees to 9.8 degrees. No significant complications were seen. Conclusion. This technique has been shown to be an effective method of correction of the complex deformity encountered in severe infantile Blount's disease. Use of the Taylor spatial frame may provide certain advantages in comparison to previously described approaches. Level of Evidence: Level IV (Case Series)

Our unpublished data has indicated that the perivascular stem cells (PSCs) have increased chondrogenic potential compared to mesenchymal stem cells (MSCs) derived in culture. There has been a recent change in the theory that stem cells work by a paracrine effect rather than differentiation. There are minimal data demonstrating the persistence of implanted stem cells when used for engraftment. This study aimed to develop an autologous large animal model for perivascular stem cells as well as to determine if cells were retained in the articular cartilage defects. The reactivity of anti-human and anti-ovine antibodies was ascertained using immunohistochemistry and fluorescence-activated cell sorting (FACS). A panel of antibodies were combined and used to identify and purify pericytes (CD34-CD45-CD146+) and adventitial cells (CD34+CD45-CD146-) using FACS. The purified cells were cultured and their identity checked using FACS. These cultured cells demonstrated osteogenic, adipogenic and chondrogenic potential. Autologous ovine PSCs (oPSCs) were isolated, cultured and transfected using a GFP virus. The transfection rate was 88%. The cells were implanted into an articular cartilage defect on the medial femoral condyle using a hydrogel, four weeks following implantation the condyle was explanted and confocal laser scanning microscopy demonstrated the presence of oPSCs in the defect. Histology did not demonstrate any repair tissue at this early time point. These data have confirmed the viability our large animal model and that the implanted stem cells were retained in the defect four weeks following implantation

Articular cartilage has very poor repair potential, however it has an extraordinary capacity to withstand physiological mechanical loads in an intact joint. The nature and extent of chondrocyte death in articular cartilage following many forms of injury (trephine, scalpel, osteotome, sutures and drilling) has been characterised, but the ability to bear mechanical injury from iatrogenic surgical interventions is still unknown. A standard arthroscopic probe was moved at varying physiological pressures along the articular cartilage of joint before staining with fluorescent dyes to allow live/dead cell imaging using laser confocal scanning microscopy and imaging software, Image J. Bovine metatarsal phalangeal joints and fresh human cadaveric femoral condyles were used. The probe caused statistically significant chondrocyte death in bovine cartilage (p=0.02). Mild pressure 5% cell death, moderate (standard arthroscopic technique pressure) 22% and severe pressure 38%. A similar result was seen in human tissue with 24% cell death at moderate pressure compared to a control (p=0.0699). The widely assumed benign arthroscopic probe produces significant cell death in articular cartilage when used at standard operating pressures

The purpose of this study is to analyze what kind of pattern of change in each posterior femoral condyle allows for a greater degree of flexion after total knee arthroplasty (TKA). The flexion angle was assessed pre-operatively, and at 12 months after the surgery in 98 patients (106 knees) who underwent consecutive TKA. We used a quantitative 3 dimensional technique using computed tomography for the assessment of changes in both the medial and lateral femoral condylar offset. There were no significant correlation between changes of each posterior condylar offset and post flexion angle (medial condyle; R=−0.038, p=0.70, lateral condyle; R=−0.090, p=0.36). There were no significant differences between changing patterns and increase rate of flexion (p=0.443). Additionally there were no significant differences between changing patterns and increase of flexion angle (p=0.593). Changes of each posterior condylar offset were no correlation to knee flexion after TKA in the current design prosthesis

Osteocondritis dissecans (OCD) is a relatively common cause of knee pain. Ideal treatment is still controversial. Aim of this exhibit is to describe the outcomes of 5 different surgical techniques in a series of 63 patients. 63patients (age 22.5±7.4 years) affected by OCD of the femoral condyle (45 medial and 17 lateral) were treated by either osteochondral autologous transplantation, autologous chondrocyte implantation with bone graft, biomimetic nanostructured osteochondral scaffold (Maioregen) implantation, bone-cartilage paste graft or bone marrow derived cells transplantation “one-step” technique. Patient evaluation included IKDC score, eq-vas score, X-Rays and MRI preoperatively and at follow-up. Global mean IKDC improved from pre-operative 40.1±14.6 to 77.2±21.3 (p<0.0005) at mean 5.3±4.7 years follow-up, while eq-vas improved from 51.7±17.0 to 83.5±18.3(p<0.0005). No influence of age, size of the lesion, length of follow-up and associated surgeries on the result was found. No differences were found between the results obtained with different surgeries except a slight tendency of better improvement in the result following autologous chondrocyte implantation (p<0.01). Control MRI evidenced a satisfactory repair of cartilaginous layer and subchondral bone. The techniques described were effective in providing good clinical and radiographic results in the treatment of OCD and confirmed the validity of autologous chondrocyte implantation over time. Newer techniques such as Maioregen implantation and “one-step” base on different rationales, the first relying on the characteristics of the scaffold and the second on the regenerative potential of mesenchymal cells. Both of them have the advantages to be minimally invasive surgeries and to require a single operation

Background. The reported outcomes of unicompartmental knee replacement (UKR) for spontaneous osteonecrosis of the knee (SPONK) often derive from small series with an average followup of 5 years, enabling to generate meaningful conclusions. Therefore, we determined the long-term functional results and the 10-years survivorship of the implant in all patients with advanced SPONK of the medial tibio-femoral compartment treated with a unicompartmental knee arthroplasty at our institute. Methods. We retrospectively evaluated 84 consecutive patients with late stage SPONK. All patients received a pre-operative MRI to confirm the diagnosis, to exclude any metaphyseal involvement and to assess the absence of significative degenerative changes in the lateral and PF compartment. Mean age at surgery was 66 years and mean body mass index (BMI) was 28.9. In all cases, SPONK involved the medial compartment; in 77 cases the medial femoral condyle (MFC) was involved, while in 7 cases the pathology site was the medial tibial plateau (MTP). Radiological evaluation was conducted by 3 different radiologists and clinical evaluation according to KSS and WOMAC score was performed by 3 fellows from outside institutions, with no previous clinical contact with the patients, at a mean followup of 98 months. Results. We found a significant improvement in VAS score for residual pain self-assessment and maximum knee flexion (p<0.0001). The 10-year Kaplan-Meier survivorship with revision for any reason as endpoint was 89%. Mean results at final observation point for global KSS and WOMAC score were 87.1 (range 45–100; standard deviation 13.8) and 12 (range 0–44; standard deviation 10.3), respectively. No patient had significant radiographic signs of osteoarthritis progression in the lateral compartment or in the patello-femoral compartment at final evaluation. Conclusions. Our findings suggest that medial UKR performed for late stage SPONK of the medial tibio-femoral compartment in selected patients provides satisfactory long term clinical and radiographical results, with a 10-years Kaplan-Meier survivorship of the implant of 89%

Several bisphosphonates are now available for the treatment of osteoporosis. Porous hydroxyapatite/collagen (HA/Col) composite is an osteoconductive bone substitute which is resorbed by osteoclasts. The effects of the bisphosphonate alendronate on the formation of bone in porous HA/Col and its resorption by osteoclasts were evaluated using a rabbit model. Porous HA/Col cylinders measuring 6 mm in diameter and 8 mm in length, with a pore size of 100 μm to 500 μm and 95% porosity, were inserted into a defect produced in the lateral femoral condyles of 72 rabbits. The rabbits were divided into four groups based on the protocol of alendronate administration: the control group did not receive any alendronate, the pre group had alendronate treatment for three weeks prior to the implantation of the HA/Col, the post group had alendronate treatment following implantation until euthanasia, and the pre+post group had continuous alendronate treatment from three weeks prior to surgery until euthanasia. All rabbits were injected intravenously with either saline or alendronate (7.5 μg/kg) once a week. Each group had 18 rabbits, six in each group being killed at three, six and 12 weeks post-operatively. Alendronate administration suppressed the resorption of the implants. Additionally, the mineral densities of newly formed bone in the alendronate-treated groups were lower than those in the control group at 12 weeks post-operatively. Interestingly, the number of osteoclasts attached to the implant correlated with the extent of bone formation at three weeks. In conclusion, the systemic administration of alendronate in our rabbit model at a dose-for-weight equivalent to the clinical dose used in the treatment of osteoporosis in Japan affected the mineral density and remodelling of bone tissue in implanted porous HA/Col composites

Introduction. An accurate and reproducible tibial tunnel placement without danger for the posterior neurovascular structures is a crucial condition for successful arthroscopic reconstruction of the posterior cruciate ligament (PCL). This step is commonly performed under fluoroscopic control. Hypothesis: Performing the tibial tunnel under exclusive arthroscopic control leads to accurate tunnel placement according to recommendations in the literature. Materials and Methods. Between February 2007 and December 2009, 108 arthroscopic single bundle PCL reconstructions in tibial tunnel technique were performed. The routine postoperative radiographs were screened according to defined quality criterions: 1. Overlap of the medial third of the fibular head by the tibial metaphysis on a-p views 2. Overlap of the dorsal femoral condyles within a range of 4 mm on lateral views 3. X-ray beam parallel to tibial plateau in both views. The radiographs of 48 patients (48 knees) were enrolled in the study. 10 patients had simultaneous ACL reconstruction and 7 had PCL revision surgery. The tibial tunnel was placed under direct arthroscopic control through a posteromedial portal using a standard tibial aming device. Key anatomical landmarks were the exposed tibial insertion of the PCL and the posterior horn of the medial meniscus. During digital analysis of the postoperative radiographes, the centre of the posterior tibial outlet was determined. On the a-p view, the horizontal distance of this point to the medial tibial spine was measured. The distance to the medial border of the tibial plateau was related to its total width. On the lateral view the vertical tunnel position was measured perpendicularly to a tangent of the medial tibial plateau. Results. The mean mediolateral tunnel position was 49,3 ± 4,6%, 6,7 ± 3,6 mm lateral to the medial tibial spine. On the lateral view the tunnel centre was 10,1 ± 4,5 mm distal to the bony surface of the medial tibial plateau. Neurovascular damage was observed in none of our patients. Conclusion. The results of this radiological study confirm that exclusive arthroscopic control for tibial tunnel placement in PCL reconstruction yields reproducible and accurate results according to the literature. Our technique avoids radiation, facilitates the operation room setting and enables the surgeon to visualize the key landmarks for tibial tunnel placement

Aims

Demineralised bone matrix (DBM) is rarely used for the local delivery of prophylactic antibiotics. Our aim, in this study, was to show that a graft with a bioactive glass and DBM combination, which is currently available for clinical use, can be loaded with tobramycin and release levels of antibiotic greater than the minimum inhibitory concentration for Staphylococcus aureus without interfering with the bone healing properties of the graft, thus protecting the graft and surrounding tissues from infection.

The augmentation of fixation with bone cement is increasingly being used in the treatment of severe osteoporotic fractures. We investigated the influence of bone quality on the mechanics of augmentation of plate fixation in a distal femoral fracture model (AO 33 A3 type). Eight osteoporotic and eight non-osteoporotic femoral models were randomly assigned to either an augmented or a non-augmented group. Fixation was performed using a locking compression plate. In the augmented group additionally 1 ml of bone cement was injected into the screw hole before insertion of the screw. Biomechanical testing was performed in axial sinusoidal loading. Augmentation significantly reduced the cut-out distance in the osteoporotic models by about 67% (non-augmented mean 0.30 mm (sd 0.08) vs augmented 0.13 mm (sd 0.06); p = 0.017). There was no statistical reduction in this distance following augmentation in the non-osteoporotic models (non-augmented mean 0.15 mm (sd 0.02) vs augmented 0.15 mm (sd 0.07); p = 0.915). In the osteoporotic models, augmentation significantly increased stability (p = 0.017).

Cite this article: Bone Joint J 2013;95-B:1406–9.

Radiological evidence of post-traumatic osteoarthritis (PTOA) after fracture of the tibial plateau is common but end-stage arthritis which requires total knee arthroplasty is much rarer.

The aim of this study was to examine the indications for, and outcomes of, total knee arthroplasty after fracture of the tibial plateau and to compare this with an age and gender-matched cohort of TKAs carried out for primary osteoarthritis.

Between 1997 and 2011, 31 consecutive patients (23 women, eight men) with a mean age of 65 years (40 to 89) underwent TKA at a mean of 24 months (2 to 124) after a fracture of the tibial plateau. Of these, 24 had undergone ORIF and seven had been treated non-operatively. Patients were assessed pre-operatively and at 6, 12 and > 60 months using the Short Form-12, Oxford Knee Score and a patient satisfaction score.

Patients with instability or nonunion needed total knee arthroplasty earlier (14 and 13.3 months post-injury) than those with intra-articular malunion (50 months, p < 0.001). Primary cruciate-retaining implants were used in 27 (87%) patients. Complication rates were higher in the PTOA cohort and included wound complications (13% vs 1% p = 0.014) and persistent stiffness (10% vs 0%, p = 0.014). Two (6%) PTOA patients required revision total knee arthroplasty at 57 and 114 months. The mean Oxford knee score was worse pre-operatively in the cohort with primary osteoarthritis (18 vs 30, p < 0.001) but there were no significant differences in post-operative Oxford knee score or patient satisfaction (primary osteoarthritis 86%, PTOA 78%, p = 0.437).

Total knee arthroplasty undertaken after fracture of the tibial plateau has a higher rate of complications than that undertaken for primary osteoarthritis, but patient-reported outcomes and satisfaction are comparable.

Cite this article: Bone Joint J 2015;97-B:532–8.

Objectives

One commonly used rat fracture model for bone and mineral research is a closed mid-shaft femur fracture as described by Bonnarens in 1984. Initially, this model was believed to create very reproducible fractures. However, there have been frequent reports of comminution and varying rates of complication. Given the importance of precise anticipation of those characteristics in laboratory research, we aimed to precisely estimate the rate of comminution, its importance and its effect on the amount of soft callus created. Furthermore, we aimed to precisely report the rate of complications such as death and infection.

This is a case series of prospectively gathered data characterising the injuries, surgical treatment and outcomes of consecutive British service personnel who underwent a unilateral lower limb amputation following combat injury. Patients with primary, unilateral loss of the lower limb sustained between March 2004 and March 2010 were identified from the United Kingdom Military Trauma Registry. Patients were asked to complete a Short-Form (SF)-36 questionnaire. A total of 48 patients were identified: 21 had a trans-tibial amputation, nine had a knee disarticulation and 18 had an amputation at the trans-femoral level. The median New Injury Severity Score was 24 (mean 27.4 (9 to 75)) and the median number of procedures per residual limb was 4 (mean 5 (2 to 11)). Minimum two-year SF-36 scores were completed by 39 patients (81%) at a mean follow-up of 40 months (25 to 75). The physical component of the SF-36 varied significantly between different levels of amputation (p = 0.01). Mental component scores did not vary between amputation levels (p = 0.114). Pain (p = 0.332), use of prosthesis (p = 0.503), rate of re-admission (p = 0.228) and mobility (p = 0.087) did not vary between amputation levels.

These findings illustrate the significant impact of these injuries and the considerable surgical burden associated with their treatment. Quality of life is improved with a longer residual limb, and these results support surgical attempts to maximise residual limb length.

Cite this article: Bone Joint J 2013;95-B:224–9.

Objectives

The use of two implants to manage concomitant ipsilateral femoral shaft and proximal femoral fractures has been indicated, but no studies address the relationship of dynamic hip screw (DHS) side plate screws and the intramedullary nail where failure might occur after union. This study compares different implant configurations in order to investigate bridging the gap between the distal DHS and tip of the intramedullary nail.