Aims

We quantitatively compared the 3D bone density distributions on CT scans performed on scaphoid waist fractures subacutely that went on to union or nonunion, and assessed whether 2D CT evaluations correlate with 3D bone density evaluations.

The purpose of this experimental study was to elucidate the accuracy of neck-cut PSG setting, and femoral component implantation using neck-cut PSG in the THA through the anterolateral-approach relative to the preoperative planning goals, and to determine the usefulness of PSG compared with the procedure without PSG. A total of 32 hips from 16 fresh Caucasian cadaveric samples were used and classified into 4 groups: cementless anatomical stem implantation with wide-base-contact PSG (AWP: 8 hips, Fig.2); (2) cementless anatomical stem implantation with narrow-base-contact PSG (ANP: 8 hips, Fig.2); (3) cementless anatomical stem implantation without PSG (Control: 8 hips); and (4) cementless taper-wedge stem implantation with wide-base-contact PSG (TWP: 8 hips). The absolute error of PSG setting in the sagittal plane of the AWP group was significantly less than that of the ANP (p=0.003).THA with wide-base- contact PSG resulted in better alignment of the femoral component than THA without PSG or with narrow- base-contact PSG. Although the neck-cut PSG did not control the sagittal alignment of taper-wedge stem, the neck-cut PSG was effective to realise the preoperative coronal alignment and medial height for THA via the anterolateral approach regardless of the femoral component type.

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Introduction

Recently, computer-aided orthopaedic surgery has enabled three dimensional (3D) preoperative planning, navigation systems and patient matched instrument, and they provide good clinical results in total knee arthroplasty. However, the preoperative planning methods and the criteria in total elbow arthroplasty (TEA) still have not sufficiently established due to the uncertainty of 3D anatomical geometry of the elbow joints. In order to clarify the 3D anatomical geometry, this study measured 3D bone models of the normal elbow joints. Additionally this study attempted to apply the 3D preoperative planning to ordinary surgery. Then the postoperative position of implant has evaluated as compared with the position in 3D preoperative planning.

Patella resection has been the least controlled element of total knee arthroplasty (TKA). We have developed an intraoperative guide system involving a custom-made surgical template designed on the basis of a three-dimensional computer simulation incorporating computed tomography (CT) data for several years. This time we have applied this intraoperative guide system for the patella resection in TKA. We investigated the accuracy of CT-based patient-specific templating (PST) for patella resection using cadaveric knee joints in vitro.

To plan the corrective patella resection, we attempted to simulate a three-dimensional patella resection with the use of computer models of the patella. From CT images of the patella we obtained three-dimensional surface models of the patella by performing a three-dimensional surface generation of the bone cortex. After the patella resection using CT-based custom-made surgical templating instrumentation, CT scan was performed again and we compared the patella shape in three-dimensional patella bone model reconstructed from pre and after cut from CT data. We compared the accuracy of patella cut using three-dimensional patella bone model reconstructed from pre and after cut from CT data. Statistical analysis was performed using paired t test.

The difference between patella cut with CT-based custom-made surgical templating instrumentation and pre-operative planning were 0.8±1.2mm (medial side) and 0.1±1.4mm (lateral side). More than 60% resulted within 2mm from the pre-operative planning. There were significant differences both in flexion/extension, external/internal rotation and bone cut depth between CT-based custom-made surgical templating instrumentation and conventional instrument.

The results in this study demonstrated the usefulness of CT-based custom-made surgical templating instrumentation for patella resection in TKA.

When total ankle arthroplasty (TAA) is performed, although tibial osteotomy is instructed to be perpendicular to long axis of tibia, there is no established index for the talar bone corrective osteotomy. Then, we have been deciding the correction angle at the plan for adjustment of the loading axis through whole lower extremities. We studied 17 TAA cases with rheumatoid arthritis (RA). X-ray picture of hip to calcaneus view (hip joint to tip of the calcaneus) defined to show more approximated loading axis has been referred for the preoperative planning. Furthermore, the data of correction angle has been reflected to pre-designed custom-made surgical guide. If soft tissue balance was not acceptable, malleolar sliding osteotomy was added. The distance between the centre of ankle joint and the axis (preD) was measured (mm) preoperatively, and the distance between the centre of prosthesis and the axis (postD) was measured postoperatively. Next, the tilting angle between tibial and talar components (defined as the index of prosthesis edge loading) were measured with X-rays during standing. Tibio Calcaneal (TC) angle was also measured pre and postoperatively.

TC angle was significantly improved from 8.3±6.0° to 3.5±3.6° postoperatively (P=0.028). PreD was 12.9±9.6mm, and that was significantly improved to 4.8±6.3mm (postD) (P=0.006). Within 17 cases, 8 cases showed 0–1mm of postD, 4 cases showed 1–5mm of postD, remaining 5 cases concomitant subtalar fusion with severe valgus and varus hindfoot deformity showed over 8mm of postD. All of the 12 cases showing within 5mm of postD indicated within 13mm of preD. The tilting angle between components was 0.17±0.37° postoperatively.

Taken together, pre-designed corrective talar osteotomy based on preoperative planning using hip to calcaneus view was useful to adjust the mechanical axis for replaced ankle joint in RA cases. Furthermore, after surgery, the hip to calcaneus view was useful to evaluate post-operative mechanical axis of whole lower extremities.

We retrospectively assessed the value of identifying impinging osteophytes using dynamic computer simulation of CT scans of the elbow in assisting their arthroscopic removal in patients with osteoarthritis of the elbow. A total of 20 patients were treated (19 men and one woman, mean age 38 years (19 to 55)) and followed for a mean of 25 months (24 to 29). We located the impinging osteophytes dynamically using computerised three-dimensional models of the elbow based on CT data in three positions of flexion of the elbow. These were then removed arthroscopically and a capsular release was performed.

The mean loss of extension improved from 23° (10° to 45°) pre-operatively to 9° (0° to 25°) post-operatively, and the mean flexion improved from 121° (80° to 140°) pre-operatively to 130° (110° to 145°) post-operatively. The mean Mayo Elbow Performance Score improved from 62 (30 to 85) to 95 (70 to 100) post-operatively. All patients had pain in the elbow pre-operatively which disappeared or decreased post-operatively. According to their Mayo scores, 14 patients had an excellent clinical outcome and six a good outcome; 15 were very satisfied and five were satisfied with their post-operative outcome.

We recommend this technique in the surgical management of patients with osteoarthritis of the elbow.

Cite this article: Bone Joint J 2014;96-B:237–41.

Introduction

Regarding TKA, patient specific cutting guides (PSCG), which have the same fitting surface with patient's bones or cartilages and uniquely specify the resection plane by fitting guides with bones, have been developed to assist easy, low cost and accurate surgery. They have already been used clinically in Europe and the USA. However little has been reported on clinical positioning accuracy of PSCG. Generally, the methods of making PSCG can be divided into 3 methods; construct 3D bone models with Magnetic Resonance (MR) images, construct 3D bone models with Computed Tomography (CT) images, and the last is to construct 3D bone models with both MR and CT images. In the present study, PSCG were made based on 3D bone models with CT images, examined the positioning accuracy with fresh-frozen cadavers.

We developed a custom-made template for corrective femoral osteotomy during THA in a patient with a previous Schanz osteotomy.

A seventy-year-old woman presented to our clinic with a chief complaint of right hip, left knee and left ankle pain with marked limp. She had undergone Schanz osteotomy of the left femur because of high dislocation of the left hip when she was 20 years old. After right THA was performed, we decided to perform left THA with corrective femoral osteotomy. A custom-made osteotomy template was designed and manufactured with use of CT data. During surgery, we placed the template on the bone surface, cut the bone through a slit on the template, and corrected the deformity as preoperatively simulated. Two years after surgery, she had no pain in any joints, could walk more than one hour without limp. Japanese Orthopedic Association hip score were 100 points for both hips.

THA in patients with previous Schanz osteotomy was reported to be technically demanding and the rate of complications was high. In 2008, Murase T et al. developed a system, including a 3D computer simulation program and a custom-made template to corrective osteotomy of malunited fractures of the upper extremity. We applied the system to corrective femoral osteotomy during THA in a patient with a previous Schanz osteotomy. The surgical procedure was technically easy and accurate osteotomy brought the patient to acquire good alignment of lower extremities with good clinical results.

We have measured the three-dimensional patterns of carpal deformity in 20 wrists in 20 rheumatoid patients in which the carpal bones were shifted ulnarwards on plain radiography. Three-dimensional bone models of the carpus and radius were created by computerised tomography with the wrist in the neutral position. The location of the centroids and rotational angle of each carpal bone relative to the radius were calculated and compared with those of ten normal wrists.

In the radiocarpal joint, the proximal row was flexed and the centroids of all carpal bones translocated in an ulnar, proximal and volar direction with loss of congruity. In the midcarpal joint, the distal row was extended and congruity generally well preserved. These findings may facilitate more positive use of radiocarpal fusion alone for the deformed rheumatoid wrist.

Background: Juxta-articular intraosseous cystic lesions (JAICL) are common lesion in patients with rheumatoid arthritis (RA) and could cause spontaneous pathological fractures and extensive joint destruction. Although surgical treatment is well indicated for benign bone tumour such as solitary bone cyst, RA induced JAICL have been rarely treated surgically because of following reasons. The first is the possible re-absorption of grafted bone due to disease progression. The second is donor site problem of iliac bone autografting. The third is limitation of autograft for possible operations in the future. The fourth is the lack of bone graft substitutes with good osteoconductivity. We have developed the interconnected porous calcium hydroxyapatite ceramic (IP-CHA) with excellent osteoconductivity. The IP-CHA achieved major incorporation with host bone much more rapid than the other porous calcium hydroxyapatite ceramics. We evaluated the feasibility and effectiveness of curettage and packing with the IP-CHA for the treatment of JAICL in RA patients.

Methods: Nine JAICL in 7 RA patients were treated by curettage and packing with IP-CHA. Eight lesions were impending pathological fractures. Two were male and five were female, the average age of operation was 57.8 years (range, forty-nine to seventy-two years). Follow-up assessment was based on final radiography at an average of 10.9 months after surgery (range, five to seventeen months). The expansion of the cystic lesions around the implanted IP-CHA and the re-absorption of the IP-CHA itself, which means erosion or increasing porosity of implanted IP-CHA, were assessed on the basis of the radiographies at just after operation and final follow up.

Results: The locations were as follows: distal radius, 6 lesions; distal ulna, 1; proximal tibia, 1; distal fibula, 1. No lesions showed the re-absorption of implanted IP-CHA itself. One of 9 lesions showed out-expansion of radiolucent area around the implanted IP-CHA without re-absoption of IP-CHA itself at the final follow-up. There were no postoperative fractures as complication.

Conclusions: These results suggested that surgical intervention with the IP-CHA could be useful for prevention of pathological fractures due to arthritis related JAICL. The efficacies of this technique might be augmented by amelioration of disease activity with concomitant drug therapy including biologics, since there was one case with out-expansion of cystic lesions in RA patients.

We studied the motor evoked potentials (MEP) in the biceps of 25 patients with traumatic brachial plexus palsy from root avulsion after cross-innervation by intercostal nerves. We used transcranial, transcervical and transthoracic magnetic stimulation at 8 to 235 months (mean 51) after transfer of intercostal nerves to the musculocutaneous nerve. Biceps strength recovered to MRC grade 2 in eight patients, grade 3 in three and grade 4 in 14. The mean latency of the MEP in the normal biceps on transcranial stimulation was 12.5 +/- 1.3 ms and on transcervical stimulation 6.3 +/- 1.1 ms. After intercostal reinnervation the mean latency on transcranial stimulation was 21.7 +/- 4.5 ms and on transthoracic stimulation 11.6 +/- 3.8 ms. The latency of the biceps MEP after reinnervation by intercostal nerves on transcranial and transthoracic magnetic stimulation correlated well with the duration of follow-up and the latency of the MEP on transthoracic magnetic stimulation correlated significantly with muscle power.

We used evoked spinal cord potentials (ESCP) for intraoperative diagnosis in 17 cases of traumatic brachial plexus palsy. Forty spinal nerves were directly stimulated during exploration of the brachial plexus and ESCP recorded from the cervical epidural space were compared with simultaneously observed somatosensory evoked potentials (SEP) and myelographic findings. Both SEP and ESCP could be evoked in 21 spinal nerves but ESCP were always more distinct and five to ten times greater in amplitude than SEP. In four nerves, ESCP but no SEP were produced, suggesting that there was continuity from the nerves to the spinal cord. ESCP were obtained from two spinal nerves which appeared to be abnormal on the myelogram. The results show that intraoperative electrodiagnosis by epidural ESCP recordings can provide useful information on the lesions of traumatic brachial plexus palsy.

Teratomas in the spinal cord are rare. We report a case in a 54-year-old man. CT scans revealed tumours of different densities within the spinal canal; this heterogeneity may help to differentiate teratoma from other spinal cord tumours. After resection of the tumours under microscopy, the result was excellent. Histological examination showed a variety of tissues, including elements of all three germinal layers.