The restoration of knee alignment is an important goal during total knee arthroplasty (TKA). In the past surgeons aimed to restore neutral limb alignment during surgery. However, previous studies have demonstrated alignment to be dynamic, varying depending on the position of the limb and the degree of weight-bearing, and between patients. We used a validated computer navigation system to measure the femorotibial mechanical angle (FTMA) in 264 knees in 77 male and 55 female healthy volunteers aged 18 to 35 years (mean 26.2). We found the mean supine alignment to be a varus angle of 1.2° (standard deviation (sd) 4), with few patients having neutral alignment. FTMA differs significantly between males and females (with a mean varus of 1.7° (sd 4) and 0.4° (sd 3.9), respectively; p = 0.008). It changes significantly with posture, the knee hyperextending by a mean of 5.6°, and coronal plane alignment becoming more varus by 2.2° (sd 3.6) on standing compared with supine.

Knee alignment is different in different individuals and is dynamic in nature, changing with different postures. This may have implications for the assessment of alignment in TKA, which is achieved in non-weight-bearing conditions and which may not represent the situation observed during weight-bearing.

Cite this article: Bone Joint J 2015; 97-B:498–502

The posterior drawer is a commonly used test to diagnose an isolated PCL injury and combined PCL and PLC injury. Our aim was to analyse the effect of tibial internal and external rotation during the posterior drawer in isolated PCL and combined PCL and PLC deficient cadaver knee.

Ten fresh frozen and overnight-thawed cadaver knees with an average age of 76 years and without any signs of previous knee injury were used. A custom made wooden rig with electromagnetic tracking system was used to measure the knee kinematics. Each knee was tested with posterior and anterior drawer forces of 80N and posterior drawer with simultaneous external or internal rotational torque of 5Nm. Each knee was tested in intact condition, after PCL resection and after PLC (lateral collateral ligament and popliteus tendon) resection. Intact condition of each knees served as its own control. One-tailed paired student's t test with Bonferroni correction was used.

The posterior tibial displacement in a PCL deficient knee when a simultaneous external rotation torque was applied during posterior drawer at 90° flexion was not significantly different from the posterior tibial displacement with 80N posterior drawer in intact knee (p=0.22). In a PCL deficient knee posterior tibial displacement with simultaneous internal rotation torque and posterior drawer at 90° flexion was not significantly different from tibial displacement with isolated posterior drawer. In PCL and PLC deficient knee at extension with simultaneous internal rotational torque and posterior drawer force the posterior tibial displacement was not significantly different from an isolated PCL deficient condition (p=0.54).

We conclude that posterior drawer in an isolated PCL deficient knee could result in negative test if tibia is held in external rotation. During a recurvatum test for PCL and PLC deficient knee, tibial internal rotation in extension results in reduced posterior laxity.

Aim: To analyse the posterior and external rotational laxities in single bundle PCL (sPCL) and double bundle PCL reconstruction (dPCL) in a PCL and PLC deficient knee.

Methods: Ten fresh frozen were used. A custom made wooden rig with electromagnetic tracking was used to measured knee kinematics. Each knee was tested with posterior and anterior drawer forces of 80N and an external rotation moment of 5Nm when intact, after PCL resection, after dividing the PLC and after performing dPCL and sPCL reconstructions with a bone patellar tendon bone allograft and tibial inlay technique.

Results: The one-tailed paired Student’s t test with Bon-ferroni correction was used. There was a significant difference between the ability of the dPCL and sPCL reconstruction to correct the posterior drawer in extension (p=0.002). There was no difference between the dPCL reconstruction and the intact condition of the knee near extension (p=0.142, Fig 1). There was no significant difference between the intact condition and both sPCL (p=0.26) and dPCL (p=0.20) reconstructions in flexion in restoring posterior laxity. Neither of the reconstructions could restore the rotational laxity (Fig 3).

Conclusion: In a combined PCL and PLC deficient knee the posterior laxity can be controlled by both the sPCL as well as the dPCL reconstructions except near extension where the dPCL reconstruction was better.

Aim: To compare the ability of two different PLC reconstruction techniques to restore the kinematics of a PCL & PLC deficient knee to PCL deficient condition.

Methods: 8 fresh frozen cadaver knees were used. A custom rig with electromagnetic tracking system measured knee kinematics. Each knee was tested with posterior & anterior drawer forces of 80N, external rotation moment of 5Nm & varus moment of 5Nm when intact, after dividing PCL, PLC (lateral collateral ligament & popliteus tendon), after PLC reconstruction type1 (1PLC) & PLC reconstruction type 2 (2PLC). 1PLC was modification of Larson’s technique with semitendinosus graft. 2PLC was performed with semitendinosus graft to reconstruct the lateral collateral ligament & the pop-liteofibular ligament, gracillis used to reconstruct pop-liteus tendon.

Results: The one-tailed paired student’s t test with Bon-ferroni correction was used to analyse the data. Only in deep flexion 2PLC reconstruction was significantly better than the 1PLC reconstruction in restoring the posterior laxity to PCL deficient condition (p=0.02). (Figure1) In deep flexion 1PLC could not restore the rotational laxity to PCL deficient condition (p=0.02). In mid flexion the 2PLC was unable to restore the rotational laxity to PCL deficient condition (p=0.048) (Figure 2).

Conclusion: The 2PLC reconstruction was better than the 1PCL in controlling the posterior drawer. The 1PLC technique though not significant tended to over constrain the external & varus rotations.

Introduction: Sciatica is the classical indication for decompression of the lumbar nerve roots. However there is a small group of patients who have atypical proximal pain i.e. pain in the groin, buttock and thigh pain without radiation below the knee, and have nerve root compression on the MRI scans. We investigated these patients with nerve root injection (NRI).

Methodology: We retrospectively studied 125-diagnostic NRIs, of these there were 12 patients (7 female & 5 male) with pain in the groin(5), thigh (4), buttock(6) & lower back(9) but no radiating pain below the knee. The MRI scans were reported independently as nerve root compression (11 L5 & 1 S1) by the radiologist. All these 12 patients were offered nerve root injection. The nerve root injection was carried out as described by Herron, under the guidance of image intensifier with bupivacaine and methylprednisolone.

Results: Of these 5 (42%) of them had temporary relief of the symptoms with nerve root injection; all of them underwent flavectomy & facetectomy of the affected nerve root. They were followed for an average duration of 39 months. Three patients were delighted with the result, 1 patient had a pain free period for 3 years then the symptoms recurred and the last patient did not benefit with the surgery.

Conclusion: We conclude that nerve root injection can be an important diagnostic tool in making a surgical decision regarding patients with such atypical symptoms.

Aim: To analyse the epidemiology of spinal injuries presented in our tertiary referral centre.

Materials and Methods: 202 patients who sustained traumatic spinal column injury were admitted in our tertiary referral centre from 1999 to mid 2002. The case notes were looked at for epidemiological details.

Results: Of 202 patients, 136 were male and the rest were females. Both in males and females, we found 2 peaks in the age incidence of spinal cord injuries. First peak was noted between the age group of 18–30 years and the second peak was noted above 60 years. We classified the spinal column injuries into upper cervical, lower cervical, thoracic, dorso-lumbar, lumber and sacral. Lower cervical and cervico-dorsal junction fractures constituted 48% of the spectrum of spinal column fractures. Significant soft tissue injury was noted in 12 patients. Multiple level spinal injuries were present in 16 patients (7.9%). Although road traffic accidents were responsible for 32% of the fractures, domestic falls also contributed to 30.6% of the fractures. 50%of these domestic falls occurred in patients above 60 years of age. We classified the falls into two categories; those from a height above 6 feet were classed as severe falls, which occurred in 65.6% of cases. Below this height the falls were classed as low falls. 71% of the patients who sustained low falls were above 60 years. Sporting accidents caused 19.8% of the spinal fractures. 27% of them are due to diving. Significantly self-harm was found to be a cause of spinal fracture in 3 patients. 67.8% (137) of the patients sustained neurological injury. Incomplete spinal cord injury was present in 86 patients and complete injury in 51 patients. Tetraplegia and tetraparesis was noted in 89 patients where as paraplegia and paraparesis was noted in 48 patients. 26 patients required ventilation at the time of admission. 63 patients sustained polytrauma of which chest injury was found in one third of the poly traumatised patients.

Conclusion: From our observations, we find that there is an increasing trend of elderly population who are more susceptible for spinal trauma. Traditional high velocity trauma and high falls though still contribute a significant proportion of spinal injuries, equal proportions of spinal fractures are caused by low falls commonly seen in elderly patients. These epidemiological trends will have implications on treatment, rehabilitation and outcome of spinal injuries.

Decision to operate for lumbar nerve root compression is usually based on the clinical findings and MRI scan evidence of nerve root compression. Decision-making is difficult in the subset of patients with pain in the groin, buttock or thigh with L5 and S1 nerve root compression as evidenced by MRI scan. We retrospectively studied 125- diagnostic nerve root injections, of which there were 12 patients who had pain in the groin, thigh or buttock and their MRI scans were reported as nerve root (11 L5 & 1 S1) compression by the radiologist. All these 12 patients were subjected to injection of the affected nerve root with bupivacaine and methylprednisolone under the guidance of image intensifier. Of these 5 (42%) of them had temporary relief of the symptoms; and all of them underwent surgical decompression of the affected nerve root. They were followed for an average of 12 months with satisfactory results. This demonstrates the importance of nerve root injections as a diagnostic tool in patients with atypical symptoms with a positive MRI scan.