Background: Venous thromboembolism (VTE) remains a significant cause of morbidity and mortality of patients following hip fracture. It is not known preoperatively which patients are at greater risk of developing VTE complications following their surgery. This study reports the incidence of VTE following neck of femur fracture, the timing of the diagnosis of VTE and any risk factors associated with VTE development.

Materials and Methods: We analysed the prospectively recorded complications of patients that presented with a neck of femur fracture. Those patients that developed VTE were compared to those with no complications and their risk factors compared.

Results: A total of 5300 patients were analysed. The incidence of VTE was 2% despite thromboprophylaxis. The significant risk factors for VTE were poor pre operative mobility (p< 0.01), those preoperatively living in their own home (p< 0.01), low mental test score (p< 0.01), high postoperative haemoglobin (p< 0.03), intertrochanteric fractures and fixation with a dynamic hip screw (p< 0.01).

Conclusions: This is the largest group of patients to be prospectively analysed for risk factors for developing VTE following surgery for neck of femur fractures. There were a number of groups that were at a significantly higher risk of developing VTE than others. Orthopaedic surgeons should be aware of these groups in the management of these vulnerable patients.

Introduction: Cervical kyphosis is failure of posterior osteo-ligamento-muscular restraint secondary to a deficient anterior column. Prospective studies of stand-alone anterior construct in correction and maintainence of cervical column that would otherwise require combined ant & post surgeries is sparse.

Objectives: To evaluate the role of stand-alone anterior surgery for cervical kyphosis, determine its efficacy and analyse complications.

Methods: 42 consecutive patients aged 6 – 70 yrs (Av 31.4 yrs) who had a Kyphosis angle of more than 100 with its apex between lower end-plate of C2 and C7 on a lateral x-ray and underwent anterior only surgery for cervical kyphosis over 6 yrs (2000–06) formed the population for this prospective study. The average follow-up was 2.2 yrs (1 – 5 yrs). The mean pre-op kyphosis was 20.820 (100 – 780). Etiology was tuberculosis in 25, dysplasia in 7, trauma in 6 and tumors in 4 cases respectively. 39 of the 42 patients had myelopathic signs. Mean pre-op mJOA score was 7.4 (0–11). A left anterior cervical approach was used in all cases. Modified manubriotomy was required in 5 cases to instrument the caudal vertebra. Tricortical iliac crest strut graft was used in 40 and cylindrical mesh cage in 2 cases. Correction of kyphosis was achieved by intra-op adjustment of the head assembly & controlled distraction. Post-operatively all wore cervical orthosis for 3 mo.

Results: 41 patients were available for analysis (1 lost for f/u). The average number of corpectomies required were 2.5 (1–4) and the mean anterior column defect reconstructed was 27.3mm (22–42mm). The average graft subsidence was 3mm (0–10mm). 2 patients required revision surgery within 6 weeks for implant failure/graft resorption. Fusion occurred in rest of 39 patients. No further graft subsidence was noticed at 4 years in 17 patients. Spontaneous fusion at 3 mo was seen in normal adjacent segment due to plate overlapping in 2 cases. The average correction achieved was 15.220 (−40–730). The mortality rate was 2.12% (1 case). Visceral complications occurred in 3 cases (esophageal perforation in 1 and recurrent laryngeal nerve palsy in 2). The mean post-operative mJOA score was 14 (9 – 17). There was 1 deep and 1 superficial infection.

Conclusion: Ant decompression & reconstruction with instrumentation facilitates neurological recovery restoring alignment. Intra-op maneuvering allows the graft to be placed in an optimal position that allows fusion under compression.

Introduction: Formulation of surgical protocol in CSM is marred by the diversity in clinico-radiological presentation. Prospective data that assigns a specific surgery with identifiable similarities in clinico-radiological attributes is sparse.

Objectives:

To identify radiological patterns of compression (POC) of the spinal cord

Methods: 135 consecutive patients aged 32–75 yrs (mean 48.1yr) operated for CSM from 1999–2005 formed the study group for this prospective series. The objectives were to identify radiological patterns of compression (POC), develop a surgical algorithm based on POC and evaluate outcome. Four POC were identified on MRI.

Pattern I – predominant one/two level compression in normal/narrow canal

Mean follow-up was 3 yrs (2–8). ACDF was performed for patterns I, II & III and posterior decompression for pattern IV and III(A). For pattern IV(A), a two stage primary posterior decompression followed by targeted ACDF at the site of maximal compression was performed. The clinical outcome was measured by modified JOA (mJOA) score, Hirayabashi Recovery Rate (HRR) and functional outcome by modified Neck Disability Index (NDI).

Results: The mean pre & post-op mJOA score was 10.40±3.33 & 15.76±1.45 respectively with average HRR of 80.10 ± 26.38. The difference in the mJOA scores was statistically significant (unpaired t test) for each POC. In multilevel CSM, anterior surgery in POC type III had statistically better post op mJOA as compared to those who underwent posterior surgery viz POC types IV and III & IV variants although the difference in their HRR and NDI were not statistically significant.

Conclusion: Anterior surgery has better neurological outcome in judiciously selected patients with multilevel CSM. Surgical decision-making guided by patterns of compression (POC) is pivotal for optimal functional outcome.

Introduction: Avulsion fractures of the anterior tibial spine are not so common. The best form of treatment for displaced fractures is still debatable.

Aims: We aimed to analyze the results of different forms of internal fixation for avulsion fractures of the anterior tibial spine.

Material and Methods: Twenty-five patients with avulsion fractures of the anterior tibial spine had open reduction and internal fixation with different implants (AO screw, Herbert screw, stainless steel wire loop and absorbable stitch) and techniques. The mean follow up period was 3.66 years. They were evaluated clinically and radiologically, using KT 1000 arthrometer for ACL laxity and goniometer for range of movements. The outcome was measured using Lysholm Knee Score.

Results: Significant residual anterior laxity despite adequate fracture union was a common finding. Maximum ACL laxity was seen in adults in whom absorbable stitches had been used and they had a corresponding lower Lysholm score. Significant migration of the Herbert screws was noted in two of five patients in which it was used. Five of the eight patients with higher Lysholm score had AO screw fixation. Three patients with steel wire loop for stabilization of the fracture also had better results comparatively. Three individuals who had their knee immobilised in 25°–50° of flexion developed fixed flexion deformities, which took 12–18 months to recover.

Conclusions: The use of absorbable stitches as the primary method of fixation for avulsion fractures of the tibial spine should be avoided in adults. Herbert screw in this situation has a tendency to migrate. AO screws and non-absorbable loop yields better functional outcome. Immobilization of the knee in excessive flexion leads to prolonged fixed flexion deformity. Early range of movements can be achieved by replacing cast with a brace allowing flexion up to 90 degrees.

At present, contact stress analyses of TKA involve in vitro experimental testing. The objective of this project was to develop a parametric mathematical model that determines in vivo contact stresses for subjects implanted with a TKA, under in vivo, dynamic conditions. It is hypothesized that the results from this model will be more representative of in vivo conditions, thus leading to more accurate prediction of TKA bearing surface stresses.

In vivo kinematics were determined for ten subjects implanted with a posterior stabilized TKA during gait and a deep knee bend under fluoroscopic surveillance. Three-dimensional contact positions, determined between the femoral component and the polyethylene insert, were entered into a complicated mathematical model to determine bearing surface forces. In vivo kinematics and kinetics were entered into a deformation model to predict in vivo contact areas between the medial and lateral condyles and tibial insert. The orientation of the femoral and tibial components, the predicted in vivo contact areas, and vectoral information of soft-tissue derived from MRI images were then entered into a mathematical model that predicted in vivo contact stresses between the femoral component and the tibial insert.

This is the first computational model that utilizes fluoroscopy, MRI, deformation characteristics and Kane’s theory of Dynamics to predict in vivo contact stresses. Although previous models have not been validated, this model was validated by comparing the predicted foot/ ground force with the experimentally derived force. This study demonstrates that patellar motion influences forces throughout the lower extremity. The in vivo contact stress values predicted in this initial study were less than the yield strength of polyethylene.

The objective of this study was to determine the location of polyethylene post position and/or axis of polyethylene (PE) bearing rotation in order to maximize the rotational freedom of the PE bearing in a posterior-stabilized mobile-bearing TKA.

Kinematic data obtained in a previous study involving subjects implanted with the PFC Sigma RP (PS) was used in two mathematical models to determine the optimal configuration of the implant’s features. An inverse dynamics mathematical model used the kinematic input to calculate interactive forces between the implant components. The second mathematical model used the femur-polyethylene and polyethylene-tibial plate interactive forces in a forward solution giving the amount of polyethylene bearing rotation. Researchers altered the location of cam/post interaction and/or bearing rotation to determine the criteria for optimal bearing rotation.

During flexion, the maximum femur-polyethylene contact force calculated by the inverse model was 1.9 x BW, at maximum flexion. Maximum quadriceps, patello-femoral, and patellar ligament forces were approx. 2.9 x BW, 2.8 x BW, and 1.5 x BW at maximum flexion, respectively. We determined that the sample group experienced an average maximum bearing rotation of approximately 3.5°. Maximum bearing rotation reached approx 12.5° (10°–15°) with a 5mm lateral shift in cam/post engagement. Bearing rotation reached approximately 17.5° (15°–20°) by shifting the bearing axis 5mm posterior to that of the current design. Shifting the cam/post mechanism or bearing axis by greater than 5mm in any direction produced undesirable results.

The mathematical models used in this study were verified by comparing kinematic results obtained from a 3-D model-fitting program whereby models are matched to their respective silhouettes in a 2-D fluoroscopic image. Results from this study show that the rotational freedom of the PE bearing can be optimized by shifting its axis of rotation posterior to its present location.

Purpose Of The Study: Avulsion fractures of the anterior tibial spine are uncommon injury and we have evaluated the results in-patients who have undergone arthrotomy and fixation of the fracture.

Material & Method: Twenty five patients were followed up between 21–108 months (mean 44 months) after the operation. They were evaluated clinically, radiologically and the residual ACL laxity was measured with KT 1000. Lysholm scoring scale has been used to assess the outcome.

Eight fractures were fixed with a single AO screw; 5 with Herbert screws; 4 with a steel wire loop and 8 with absorbable stitch.

Results: Significant residual anterior laxity despite adequate fracture union was a common finding. The ACL laxity was maximum in adults in whom absorbable stitch had been used to fix the fracture and they had a corresponding lower Lysholm score.

In 2 out of the 5 patients where Herbert screws had been used there was significant migration of the screws.

Additional articular damage was observed in 3 patients who were pedestrians hit by a car. All 3 ended up with restricted knee movements and poor results. Three individuals who had their knee immobilised in 250–500 of flexion developed flexion deformities, which took 12–18 months to recover.

Conclusions: We recommend that use of absorbable stitches as a method of fixation be avoided in adults. Herbert screws in this situation have a tendency to migrate. AO screws or a non-absorbable loop should be used were possible. Immobilisation of the knee in excessive flexion leads to prolonged flexion deformity and we recommend immobilising the knee in no more than 100 of flexion.

Background: Autologous blood from reinfusion drains are commonly used after major joint arthroplasties with a view to decrease the heterologous blood transfusion requirement. The aim of this study is to find the effect of reinfusion drains on the difference in haemoglobin (Hb) level before and after total knee arthroplasties.

Material and Methods: Between January 2001 and October 2003, 158 patients had total knee arthroplasty on one side. The type of thromboprophylaxis used was the same in all the patients. 74 patients had autologous blood transfusion through reinfusion drains (Group I) while 84 patients had no autologous blood transfusion and ordinary suction drains were used to drain the wound in the immediate postoperative period (Group II). The mean age was 72.1 +/− 8.5 in group I and 69.3 +/− 9.1 in group II. In each patient the preoperative Hb level, the amount of autologous blood transfusion, the postoperative Hb level and the amount of heterologous bleed transfusion requirement were noted.

Results: The mean preoperative Hb level was 13.6 +/− 1.4 g/dL (10.4–18.1) in group I and 13.7 +/− 1.3 g/dL (7.9–16.5) in group II. The mean postoperative Hb level was 10.7 +/− 1.5 g/dL (10.4–18.1) in group I and 10.7 + 1.6 g/dL (5.4 +/− 13.6) in group II. The difference in Hb level between the two groups was analysed using t-test and found to be not significant (p = 0.76), with the mean difference between the groups being 0.05 and the 95% CI to the mean difference includes zero (range −0.3 to +0.4). The difference in Hb level before and after surgery was plotted against the amount of autologous blood transfused and it was observed that there was no significant improvement with increased amount of autologous blood transfusion. The cost of reinfusion drain is 36.43 (~ 53.37 Euros) more than the suction drain.

Conclusion: Autologous blood from reinfusion drains did not significantly improve the postoperative Hb level. Further usage of reinfusion drain is not cost-beneficial.

Background Non-weight bearing hip is a common problem in the elderly population after a minor fall. Magnetic reasonance imaging (MRI) is used to diagnose occult fractures in the hip and the pelvic ring in these individuals. The aim of this study is to find the relationship between the incidence of occult fractures in the hip and that in the pelvic ring following low velocity trauma in the elderly.

Material and Methods Between January 2000 and February 2004, 106 elderly patients (mean age = 81.4 years; range = 67–101 years), underwent an MRI scan of the pelvis and hip to rule out fracture neck of femur. All of them presented with a non-weight bearing hip after a history of low velocity injury. All had standard radiographs of the pelvis and the hip which did not reveal a fracture of the femoral neck. However, eight patients had fracture of the pubic rami visible on plain radiographs. MRI scans were subsequently performed in all of them to rule out an occult fracture of the femoral neck.

Results Out of the 106 patients, 17 (16%) had intracapsular neck of femur fracture, 26 (24.5%) had extracapsular neck of femur fracture, 26 (24.5%) had pubic rami fracture, 17 (16%) had sacral fractures, and 37 (34.9%) had no fractures. All the sacral fractures occurred in patients with pubic rami fractures. Further except in one patient where the pubic rami fracture and the sacral fracture were contralateral, the remaining 16 patients had ipsilateral pubic rami and sacral fractures. None of the patients with pelvic ring fracture had associated femoral neck fracture.

Conclusion Inability to weight bear after a fall is a common presentation in the elderly population. Falls can lead to fracture neck of femur or a fracture of the pelvic ring but seldom both. We can also conclude that in an elderly patient with low velocity injury, if a pelvic ring fracture is detected in the plain radiograph there is no indication for further MRI to rule out femoral neck fracture. Further, the fracture in the anterior and posterior pelvic ring commonly involves the same side than the contralateral side, in the elderly after trivial trauma.