Bicondylar tibial plateau fractures result from high-energy injuries. Fractures of the tibial plateau can involve the tibial tubercle, which represents a disruption to the extensor mechanism and logically must be stabilised. The purpose of this study was to identify the incidence of an independent tibial tubercle fracture in bicondylar tibial plateau fractures, and to report management strategies and potential complications. We retrospectively reviewed a prospectively collected orthopaedic trauma database for the period January 2003 to December 2008, and identified 392 bicondylar fractures of the tibial plateau, in which 85 tibial tubercle fractures (21.6%) were identified in 84 patients. There were 60 men and 24 women in our study group, with a mean age of 45.4 years (18 to 71). In 84 fractures open reduction and internal fixation was undertaken, either with screws alone (23 patients) or with a plate and screws (61 patients). The remaining patient was treated non-operatively. In all, 52 fractures were available for clinical and radiological assessment at a mean follow-up of 58.5 weeks (24 to 94). All fractures of the tibial tubercle united, but 24 of 54 fractures (46%) required a secondary procedure for their tibial plateau fracture. Four patients reported pain arising from prominent tubercle plates and screws, which in one patient required removal. Tibial tubercle fractures occurred in over one-fifth of the bicondylar tibial plateau fractures in our series. Fixation is necessary and can be reliably performed with screws alone or with a screw and plate, which restores the extensor mechanism and facilitates early knee flexion. Cite this article: Bone Joint J 2013;95-B:1697–1702

The treatment of fractures has evolved from extensive open reduction and internal fixation to minimally invasive surgery and biological fixation. High energy bicondylar tibial plateau fractures pose a treatment challenge to most orthopaedic Surgeons. This study evaluates the results of biologic plating of bicondylar tibial plateau fractures. Between January 2005 and January 2006 we treated 25 closed bicondylar tibial plateau fractures with minimally invasive surgery using locking plates and screws. Routine tomograms and CT scans were performed after a detailed history and physical examination were performed. Pre-operative planning and templating was performed in all cases. Surgery was carried out by the same surgical team using a tourniquet and an anterolateral or medial surgical approach. Bone grafting was also performed in some cases. The implants used were pre-contoured locking plates (Synthes, Smith & Nephew). The rehabilitative programme was commenced on day 2 by the same Physiotherapist and non weight bearing for 12 weeks. Four patients refused to be part of the study and two were lost to follow up. Nineteen patients were available for follow up with a mean follow up of 10 months. There were 10 males with mean age of 35 years. Two patients were treated for early superficial wound sepsis which healed. Eight patients needed a bone graft at the time of surgery. The average range of movement was 5–110 degrees of flexion. There were no implant failures or non unions. At six months all patients walked unaided with no deformity and were satisfied with the operation. As an alternative to external fixation of these difficult fractures we recommend a less invasive precontoured plate with locking screws. The advantages include sub-muscular, extraperiostal plate application through a relatively small incision, percutaneous screw placement through a guide, the fixed angle of the plate obviating the necessity of medial plate fixation, and plate lengths are available to span the metadiaphysis. The results suggest that biologic plating with a precontoured locking plate of bicondylar tibial plateau fractures may give better short term results with excellent function

We describe two cases of osteochondritis dissecans (OCD) affecting both femoral condyles in the same knee. The patients presented with recurrent episodes of pain and swelling, but these were initially thought to be ‘growing pains’. Eventually, a delayed diagnosis of bicondylar OCD was established and both patients were referred for further management. After assessing the extent of the disease on MRI, matrix-induced autologous chondrocyte implantation was performed to treat the defects of the lateral condyle in each case, with a plan to address the medial defects at a later stage. Proposed theories on the aetiology of the condition and available methods of treatment are discussed. A diagnosis of OCD should be considered in young patients with persistent knee pain and effusions, and MRI is the investigation of choice for early detection

Aim: The purpose of the present retrospective study was to evaluate reasonable routine transposition of the ulnar nerve in bicondylar humeral fractures. Material and method: From 1996 to 2007 112 bicondylar fractures were operated. 88 pateints (47 women and 41 men) were followed up for average 56 months. Average age was 48 (14–80) years. Open fractures were 17. Fractures were distributed by the AO classification as follows: type C1.2 – 16, C1.3 – 10, C2.1 – 22, C2.2 – 7, C2.3 – 3, C3.1 – 17, C3.2 – 8 and C3.3 -5. All fractures were operated by the AO method with dorsal approach, osteotomy of the olecranon (83 fractures) and fixation with 2 plates. In 47 cases the ulnar nerve was routinely anteriorly transposed and for the rest 41 patients transposition was not done. Results: From 47 patients with routine anterior transposition 7 had Mc Gowan I dysfunction that was resolved in 3 months. From 41 patients without transposition 9 had a type Mc Gowan I dysfunction. There was no statistical significance between the two groups. (p> 0,05). However, 12 to 18 months later 3 patients from the group without transposition with type C1.3, C3.1 and C3.3 fractures returned with late postoperative nerve palsy Mc Gowan II and III. They were treated by neurolysis and transposition. Conclusion: Routine anterior transposition of the ulnar nerve is not reasonable in every type of bicondylar humeral fractures. The type of the bicondylar fracture defines whether the nerve transposition is reasonable or not. In low bycondilar humeral fractures and type C3 fractures the nerve transposition is obligatory

Aim of the Study: Evaluation of differences in pro-prioception, gait analysis, electromyography in consideration of clinical results in patients with unicondylar and bicondylar knee arthroplasty. Material and Methods: 17 patients with mean age of 62.5 years were examined after a mean time of 21.5 months after unicondylar knee arthroplasty and compared with 15 patients with a mean age of 67 years and a mean time of 31.9 months after bicondylar knee arthroplasty. For clinical examination the Knee Society, Hospital for Special Surgery and Patella Score were used. Proprioception was examined using the Balance test. In addition each patient was examined by gait analysis with three-dimensional-kinematics and force plate. M. rectus femoris, M. vastus medialis/lateralis, M. semiten-dinosus, M. biceps femoris, M. tibialis anterior and M. gastrocnemius were examined by electromyography. Results: There were neither significant deviations in demographic data, clinical scores, electromyography results (except M. vastus lateralis), gait analysis nor in proprioception. Conclusion: There were no deviations in any clinical or functional results in patients with unicondylar and bicon-dylar knee arthroplasty. Because of the uncertain long term results of unicondylar knee arthroplasty in respect of loosening and development of contralateral osteoarthritis, bicondylar knee arthroplasty can be approved

Aim: To present and analysis the neurological complications after ORIF with plates of bicondylar fractures of the humerus. Material and Methods: For the period 1996 – 2003 77 bicondylar fractures were operated with plates. All of them were followed up. 36 Man and 41 women. Dominant hand was affected in 43 patients. The AO types were C1- 25, C2 – 28, C3 – 24. There were 18 open fractures (I–II degree). High-energy trauma caused 19 fractures. 14 were with associated ipsilateral fractures of the upper limb. All patients were operated by the standard AO technique. In all patients the ulnar nerve was identified. There was no case where the radial nerve was exposed. In 36 patients the nerve was transposed anteriorly subcutaneosly and for the rest it was not. Results: We observed 20 postoperative ulnar and radial nerve disfunctions (19 ulnar nerve and 1 radial nerve disfunctions). Electromiography was performed in all cases. 7 of 36 (with transposition) cases finished with temporary ulnar nerve palsy. 3 of 41 (without transposition) cases finished with permanent ulnar nerve palsy and the other 9 of 41 finished with temporary disfunction. The disfunction of the radial nerve was temporary. The temporary neurological disfunctions recovered completely for 3–7 months. Neurolysis and anterior transposition of the ulnar nerve was performed in the cases with permanent ulnar nerve palsy. Conclusions: We suggest that ulnar nerve transposition is a method of choice in operative treatment of bicondylar fractures of the humerus. Careful management of the ulnar nerve is mandatory. Meticulous soft-tissue dissection and hemostasis help to prevent perineural fibrosis

Aim: In order to determine the reliability of the ORIF of bicondylar fractures in elderly patients, we will present the results of the patients aged above 60 years in which ORIF with plates is a method of choice. Materials & Method: For the period 1996–2001 year, 20 patients with dislocated bicondylar fractures were operated with mean age Ð 70.7 (63.8). All of them were followed up Ð 14 women and 6 men. The AO types were: C1 Ð 7; C2 Ð 5; C3 Ð 8. Five patients were with þrst and second type open fractures. Fifteen patients were operated immediately and the rest Ð between the 5th and the 10th day. The average operative time was 335 minutes. The patients were operated by the standard technique of AO. Osteotomy of the olecranon was used in all patients except for 3 patients. All the fractures were stabilised with 2 plates except for 2 patients (1 plate). The osteotomy was þxated with a tension wire and K-wires. Carefully assisted rehabilitation was started at average on the 9th day. Results: The patients were monitored for 13 to 56 months. None had serious infections. One case resulted in failure of þxation and nonunion. In order to assess the function of the elbow joint we used Morrey& Chao, DASH, and average arch of movement. Scoring: 83,02 (±24,59); 20,10 (±21,66); 97û(±37,83).Conclusions: We consider that the operative treatment with plates of the bicondylar fractures in the elderly can provide good clinical results in the hands of the experienced surgeon

Purpose: To evaluate the functional outcome following internal fixation of bicondylar distal humerus fractures (AO type C) using the ACUMED modified titanium plates. Material-Methods: Fourteen patients (9 male, 5 female) aging 18 to 78 years (av. 54 y.) with bicondylar distal humerus fractures, between September 2002 and May 2004, were included in our study. All of them underwent open reduction and internal fixation. The articular surface was reduced through a transolecranic approach using one or two compression screws and the fractures was then fixated using the modified titanium ACUMED plates. Results: Postoperative follow-up ranged from 6 to 24 months (av. 12 m.). The results were evaluated using the Mayo Clinic Score. The mean range of elbow flexion-extension was 115o. Nine patients had an excellent/good result, 3 had affair and 2 a poor result. One patient underwent a second procedure for symptomatic metalwork. In one case there was soft tissue infection that resolved successfully with antibiotic administration. Conclusion: The internal fixation of bicondylar AO (type C) distal humerus fractures with the ACUMED plates through a transolecranic approach is an extensive but atraumatic operation that offers excellent reduction and a stable osteosynthesis leading to a good functional outcome

Objective: To compare the mechanical stability of fixation of bicondylar tibial plateau fractures using available internal and external fixation techniques. Method: A bicondylar tibial plateau fracture was simulated on a uniform synthetic bone and tested with loading to failure. Following power calculations, seven tibias were used for each fixation method; five types of fixation were tested: 1) Dual plating. 2) Ring Fixator with inter-fragmentary screws. 3) Hybrid fixator (Ring-Bar) with interfragmentary screws. 4) Lateral plate and medial monolateral external fixator. 5) Lateral plate and medial interfragmentary screws. The specimens were tested in compression to failure. The vertical subsidence in either medial or lateral plateau was measured using an electrical transducer. Results: In all cases the mode of failure was consistent with collapse occurring in the medial plateau. There was no significant difference in the ultimate strength between dual plating and the ring fixator [4218N, 4184N respectively; P=0.28, t test]. Failure was seen at lower loads with the other fixation systems (Table). Conclusion: The Ring Fixator and dual plating demonstrated a greater strength and the most stable fixation, choice may depend on tissue viability and surgeon preference. Furthermore mobilisation of the patient may be undertaken earlier with more confidence using these two methods rather than less stable techniques

Introduction: Total knee replacement has become a common procedure with good clinical results. Today many different designs of the femoral component of bicondylar endoprostheses are offered by industry. The femoral components show similar designs however different angles and length of the cross sections are specific. Because of these design differences the preoperative planning and sparing bone resection are difficult at the revision surgery. The aim of this experimental study was to compare the design of femoral components at their cross section contours to find congruence and differences of common bicondylar endoprostheses to prove the possibility of design exchange during revision surgery. Material and method: Ten femoral components (e.motion. ®. , Genesis II, Genia. ®. , Innex. ®. , LCS. ®. , Multigen Plus, NexGen. ®. , P.F.C. ®. , Scorpio. ®. , Vanguard. ®. ) of similar implant size were analysed with regard to their cross section design. Therefore the constructional properties of the inner surface (direction and length of cross sections) of the components were determined. The components were scanned with a three-dimensional laser scanner and were transferred to two dimensional CAD models to the lateral and frontal view in order to compare the inner contours. The contours of the cross sections were overlaid with congruence of the posterior and anterior cross section of all components at lateral view. Results: Four of the ten analysed femoral components showed good congruence of the cross sections. Here, only a few additional bone resections or extra bone cement have to be done at the diagonal cross sections to change the femoral design among each other. Four other components show wide differences between the inner contours in comparison to the first four components especially at their posterior and diagonal cross sections. Two components can not be compared with the others due to their diagonal distal cross section. Discussion: The numerical results shows good congruence of cross section contours of some analysed femoral components. Furthermore there were clear design differences which complicate the exchange of the femoral component at revision surgery. The use of an elementary inner contour of femoral components of bicondylar endoprostheses could be an advantage for revision arthroplasty in regard to bone sparing surgical treatment

Objective: To assess the inßuence of bone density on the þxation strength of bicondylar tibial plateau fractures. Method: Sixteen cadaver tibias were randomised into two groups to receive either dual plating or ring external þxation to stabilise a bicondylar tibial plateau fracture created with a standard method. The randomisation was stratiþed by BMD measured by DXA (above and below the mean). Cyclic axial compression tests were performed with increasing peak loads. Inter-fragmentary shear displacements were measured using four extensometers. Failure was deþned as over 3mm displacement. Results: There was a strong correlation between failure load and BMD [r=0.81, P< 0.001]. The mean failure load of the low BMD group (2701 N) was signiþcantly less than that with the high BMD (4530 N) [t-test=0.003]. The failure loads of the two þxation groups were not signiþcantly different (3520 N for the dual plating and 3710 N for the external þxation) [t-test=0.78]. BMD had a signiþcant effect on the failure load in the dual plating group [t-test=0.03], but not in the external þxation group [t-test=0.1]. Discussion: Failure of þxation has been reported as a common complication of bicondylar tibial plateau fractures with a rate as high as 30%. Osteoporosis and poor bone quality are considered important contributory factors. In our study this inßuence was evident with plating, but not with ring þxation. Ring þxation may be the preferred method of þxation for tibial plateau fractures in the elderly and osteoporotic patients

Objective: To compare the mechanical stability of þxation of bicondylar tibial fractures using available internal and external þxation techniques. Method: A bicondylar tibial fracture was simulated on a uniform synthetic bone and tested with loading to failure. Following power calculations, seven tibias were used for each þxation method;þve types of þxation were tested: 1)Dual plating. 2)Ring Fixator with interfragmentary screws. 3)Hybrid þxator (Ring-Bar) with interfragmentary screws. 4)Lat-eral plate and medial monolateral external þxator. 5)Lateral plate and medial interfragmentary screws. The specimens were tested in compression to failure. The vertical subsidence in either medial or lateral plateau was measured using an electrical transducer. Results: In all cases the mode of failure was consistent with collapse occurring in the medial plateau. There was no signiþcant difference in the ultimate strength between dual plating and the ring þxator [4218N, 4184N respectively; P=0.28, t test]. Failure was seen at lower loads with the other þxation systems. Conclusion: The Ring Fixator and dual plating demonstrated a greater strength and the most stable þxation, choice may depend on tissue viability and surgeon preference. Furthermore mobilisation of the patient may be undertaken earlier with more conþdence using these two methods rather than less stable techniques

Purpose of Study. Bicondylar tibial plateau fractures are serious injuries to a major weight bearing joint. These injuries are often associated with severe soft tissue injuries that complicate the surgical management. This retrospective study evaluates the management of these high-energy injuries with the use of limited open reduction and fine wire circular external fixation. Methods. Between July 2008 and June 2012, 54 consecutive patients (19 females and 35 males) with high-energy tibial plateau fractures were treated at our tertiary level government hospital. All patients were treated with limited open reduction, and cannulated screw fixation combined with fine wire circular external fixators as the definitive management. The records of these patients were reviewed. Results. Forty-six patients met the inclusion and exclusion criteria. Thirty-six patients had Schatzker type-VI and ten patients had Schatzker type-V fractures. All fractures united without loss of operative reduction. No wound complications, osteomyelitis or septic arthritis occurred. Average Knee Society Clinical Rating Score was 81.6, translating to good clinical results. Minor pin tract infection was the most common complication encountered. Conclusion. Fine wire circular external fixation combined with limited open reduction and cannulated screw fixation consistently produced good functional results without serious complications. NO DISCLOSURES

Purpose: To compare locking and non-locking single and dual plating constructs in maintaining posteromedial fragment reduction in a bicondylar tibial plateau fracture model. We hypothesized that posteromedial fragment fixation with medial and lateral non-locked constructs would tolerate higher loads than lateral locked constructs alone. Method: Thirty adult-sized composite tibiae were identically fractured into an AO 41-C1.3 pattern. Six plate constructs were tested:. lateral 8-hole 3.5 mm conventional non-locking proximal tibial plate [CP];. CP + posteromedial 6 hole 3.5 mm limited contact dynamic compression plate [CP + LCDCP];. CP + postero-medial 6 hole 1/3 tubular plate [CP + 1/3 tubular];. 8-hole 3.5mm Proximal Tibial Locking plate [PTLP];. 8-hole 3.5 mm LCP (locking compression plate) proximal tibia plate [LCP];. 9-hole Less Invasive Stabilization System [LISS] plate. Specimens were cyclically loaded to failure or a maximum load of 4000N. Load at posteromedial fragment failure was recorded. Results: Fragment failure occurred at the posteromedial fragment first. The CP + 1/3 tubular construct had the highest average load to failure (3040 N). In two instances, the CP + 1/3 tubular construct did not fail under the highest loads applied and was the only construct to have specimens that did not fail by 4000 N. The CP + 1/3 tubular plating construct demonstrated significantly higher load at failure compared with the PTLP (p=0.036), the LCP (p=0.004), and the LISS (p=0.012). The CP + 1/3 tubular group did not demonstrate a significant difference in load at failure when compared with the CP (p=0.093) or the CP + LCDCP (p=0.108). The LISS demonstrated a significantly higher load at failure compared to the LCP (p=0.046) but not to the PTLP (p=0.800). Conclusion: The posteromedial fragment tolerated higher loads with the CP + 1/3 tubular plate construct. The superiority of the dual plate construct may in part be due to the unreliable penetrance of the posteromedial fragment by the laterally applied locking screws

In five teaching hospitals, seventy-two patients with seventy-three bicondylar tibial plateau fractures were prospectively randomized by envelope to treatment either by AO methods (group A) or ring fixator methods (group B). Outcome measures included clinical and radiographic parameters, & HSS knee scores. Results: Re-intervention was necessary within six months in ten group A & seven Group B patients. Forty-three procedures were performed (thirty-three Group A-ten Group B) I& D 12- 3: STSG 3-0: Quadricepsplasty 1-0; Manipulation 2–4; Muscle flap 2–0; Above knee amputation 1–0; Revision ORIF 5–1; Revision Rings 0–1; Bone graft 2–1; Bead pouch 3-0; Synovectomy 1-0; Sequestrectomy 1-0. More patients had more septic and wound complications resulting in more need for re-intervention following ORIF. Conclusion. For bi-condylar tibial plateau fractures (OTA 41.C) six-month HSS scores are significantly higher after treatment with Ring Fixator methods. Reintervention rates for deep sepsis/wound problems are higher with AO methods. Wound and infection complications occurring after AO treatment are more severe and require multiple procedures for control. We have conducted a prospective randomized trial to determine the outcomes of treatment by. Open reduction and internal fixation or. Closed reduction and ring fixation for the treatment of bi-condylar tibial plateau fractures (OTA 41.C). We report our early findings on re-intervention rates for complications. In five teaching hospitals, seventy-two patients with seventy-three bi-condylar tibial plateau fractures were prospectively randomized by envelope to treatment either by AO methods (group A) or ring fixator methods (group B). Outcome measures included clinical and radiographic parameters, & HSS knee scores. Randomization gave the following demographics. Re-intervention was necessary within six months in ten group A & seven Group B patients. Forty-three procedures were performed (thirty-three Group A-ten Group B) I& D 12- 3: STSG 3-0: Quadricepsplasty 1-0; Manipulation 2-4; Muscle flap 2-0; Above knee amputation 1-0; Revision ORIF 5-1; Revision Rings 0-1; Bone graft 2-1; Bead pouch 3-0; Synovectomy 1-0; Sequestrectomy 1-0. More patients had more septic and wound complications resulting in more need for re-intervention following ORIF. For bi-condylar tibial plateau fractures (OTA 41.C) six-month HSS scores are significantly higher after treatment with Ring Fixator methods. Reintervention rates for deep sepsis/wound problems are higher with AO methods. Wound and infection complications occurring after AO treatment are more severe and require multiple procedures for control. Please contact author for pictures and/or diagrams

The primary objective of implanting a total knee prosthesis is to release the patient from pain and to improve the joint mobility at the same time. This leads to an increased quality of life that is optimally kept for the patient's residual lifespan. Joint mobility and stability requires an intra-operative soft-tissue balancing. To reach the goal of a correct implant positioning and well-balanced ligaments two different operative procedures can be used: the so-called “Femur-first”-technique and the “Tibia-first” technique. Since now more than ten years the CT-free navigation is established as a routine procedure in TKA. Studies investigating this innovative technique have shown to lead to a higher precision regarding implant positioning and leg alignment. The present study compares navigated “Femur-first”-technique and “ Tibia-first”-technique. We hypothesised that, due to its better soft-tissue balance, the tibia first technique (T) would allow a flexion improvement of 10° compared to the femur first technique (F).

Between February 21, 2008, and October 10, 2009, 116 consecutive patients were implanted a Columbus® non-constrained total knee replacement (Aesculap®, Tuttlingen, Germany) using navigation; they were examined before the operation and 1 year after. The TKAs were performed by 3 surgeons experienced in knee replacement surgery. We used the femur first technique (F) in 63 patients, the tibia first technique (T) in 53 patients. We performed the final flexion measurement one year after the operation using a Goniometer and evaluated standing full-length radiographs. In addition, we took standard varus and valgus stress radiographs to evaluate the stability of the collateral ligaments and determine the relative position of the implants to one another. Finally, to compare the two patient groups, we used the following pain and function scores: Knee Society Score (KSS), Oxford Score, Knee Injury and Osteoarthritic Outcome Score (KOOS), Short Form 36 (SF 36), Tegner Lysholm Score.

Concerning maximal flexion as the main parameter, we did not find any significant difference between the F and T groups (maximal flexion in group F: 113.4± 9,8° and in group T: 113.5± 8.4°; p = 0.963); thus we could not confirm our hypothesis. Radiological evaluation of the stability of the collateral ligaments did not reveal any significant difference between the two groups both in the medial and lateral joint cavity (lateral collateral ligament in group F: 3.4± 1.4°, and in group T: 3.9± 1.7°; p = 0.850, and medial collateral ligament in group F: 4.0± 1.4°, and in group T: 4.1± 1.7°; p = 0.086). Concerning the mechanical axis on the standing full-length radiograph as part of the 1-year results, no significant difference was found between the two groups (p = 0.089). Likewise, the pain and function scores did not show any difference between the two groups.

Concerning operating time (OP time) and outliers exceeding 3° of varus/valgus deviation from the ideal mechanical axis, trends were identifiable. The number of outliers tended to be higher in the F group, the OP time in group T seemed longer.

As a conclusion, we can say that both the tibia first and the femur first techniques yield good clinical and radiological results in combination with navigation. In terms of function and patient satisfaction, we did not find any significant difference.

Introduction

Proximal tibial fractures frequently present in combination with other injuries which also have to be treated surgically. Recent publications do not consider isolated proximal tibial fracture (mono-injury) and combined injuries which include tibial fractures as two seperate medical entities. We therefore asessed the influence of additional injuries on treatment and outcome of the proximal tibial fractures.

Aims. This study aims to investigate the effects of posterior tibial slope (PTS) on knee kinematics involved in the post-cam mechanism in bi-cruciate stabilized (BCS) total knee arthroplasty (TKA) using computer simulation. Methods. In total, 11 different PTS (0° to 10°) values were simulated to evaluate the effect of PTS on anterior post-cam contact conditions and knee kinematics in BCS TKA during weight-bearing stair climbing (from 86° to 6° of knee flexion). Knee kinematics were expressed as the lowest points of the medial and lateral femoral condyles on the surface of the tibial insert, and the anteroposterior translation of the femoral component relative to the tibial insert. Results. Anterior post-cam contact in BCS TKA was observed with the knee near full extension if PTS was 6° or more. BCS TKA showed a bicondylar roll forward movement from 86° to mid-flexion, and two different patterns from mid-flexion to knee extension: screw home movement without anterior post-cam contact and bicondylar roll forward movement after anterior post-cam contact. Knee kinematics in the simulation showed similar trends to the clinical in vivo data and were almost within the range of inter-specimen variability. Conclusion. Postoperative knee kinematics in BCS TKA differed according to PTS and anterior post-cam contact; in particular, anterior post-cam contact changed knee kinematics, which may affect the patient’s perception of the knee during activities. Cite this article: Bone Joint Res 2020;9(11):761–767

Unstable bicondylar tibial plateau fractures are rare and there is little guidance in the literature as to the best form of treatment. We examined the short- to medium-term outcome of this injury in a consecutive series of patients presenting to two trauma centres. Between December 2005 and May 2010, a total of 55 fractures in 54 patients were treated by fixation, 34 with peri-articular locking plates and 21 with limited access direct internal fixation in combination with circular external fixation using a Taylor Spatial Frame (TSF). At a minimum of one year post-operatively, patient-reported outcome measures including the WOMAC index and SF-36 scores showed functional deficits, although there was no significant difference between the two forms of treatment. Despite low outcome scores, patients were generally satisfied with the outcome. We achieved good clinical and radiological outcomes, with low rates of complication. In total, only three patients (5%) had collapse of the joint of > 4 mm, and metaphysis to diaphysis angulation of greater than 5º, and five patients (9%) with displacement of > 4 mm. All patients in our study went on to achieve full union. This study highlights the serious nature of this injury and generally poor patient-reported outcome measures following surgery, despite treatment by experienced surgeons using modern surgical techniques. Our findings suggest that treatment of complex bicondylar tibial plateau fractures with either a locking plate or a TSF gives similar clinical and radiological outcomes. Cite this article: Bone Joint J 2014;96-B:956–62

Introduction. Within the reconstruction of unicondylar femoral bone defects with morselized bone grafts in revision total knee arthroplasty (TKA), a stem extension appears to be critical to obtain adequate mechanical stability. Whether the stability is still secured by this reconstruction technique in bicondylar defects has not been assessed. Long, rigid stem extensions have been advocated to maximize the stability in revision TKAs. The disadvantage of relatively stiff stem extensions is that bone resorption is promoted due to stress shielding. Therefore, we developed a relatively thin intramedullary stem which allowed for axial sliding movements of the articulating part relative to the intramedullary stem. The hypothesis behind the design is that compressive contact forces are directly transmitted to the distal femoral bone, whereas adequate stability is provided by the sliding intramedullary stem. A prototype was made of this new knee revision design and applied to the reconstruction of uncontained bicondylar femoral bone defects. Materials and Methods. Five synthetic distal femora with a bicondylar defect were reconstructed with impacted bone grafting (IBG) and this new knee revision design. A custom-made screw connection between the stem and the intercondylar box was designed to lock or initiate the sliding mechanism, another screw (dis)connected the stem. A cyclically axial load of 500 N was applied to the prosthetic condyles to assess the stability of the reconstruction. Radiostereometry was used to determine the migrations of the femoral component with a rigidly connected stem, a sliding stem and no stem extension. Results. We found a stable reconstruction of the bicondylar femoral defects with IBG in case of a rigidly connected stem. After disconnecting the stem, the femoral component showed substantially more migrations. With a sliding stem rotational migrations were similar to those of a rigidly connected stem. However, the sliding stem allowed proximal migration of the condylar component, thereby compressing the IBG. Discussion. A stable reconstruction of uncontained bicondylar femoral defects could be created with IBG and a TKA with a thin stem extension. It appeared that the presence of a functional stem extension was important for the stability of the bicondylar reconstruction. In an effort to reduce stress shielding, we developed a sliding stem mechanism. This sliding stem provided adequate stability, while compressive contact forces are still transmitted to the distal femoral bone. Clinical studies have to confirm that our sliding stem mechanism leads to long term bone maintenance after revision TKAs