Hip resurfacing arthroplasty (HRA) is a bone conserving alternative to total hip arthroplasty. We present the early 2-year clinical and radiographic follow-up of a novel ceramic-on-ceramic (CoC) HRA in an international multi-centric cohort. Patients undergoing HRA between September 2018 and January 2021 were prospectively included. Patient-reported outcome measures (PROMS) in the form of the Forgotten Joint Score (FJS), HOOS Jr, WOMAC, Oxford Hip Score (OHS) and UCLA Activity Score were collected preoperatively and at 1- and 2-years post-operation. Serial radiographs were assessed for migration, component alignment, evidence of osteolysis/loosening and heterotopic ossification formation. 200 patients were identified to have reached 2-year follow-up. Of these, 185 completed PROMS follow-up at 2 years. There was significant improvement in HOOS (p< 0.001) and OHS (p< 0.001) and FJS (p< 0.001) between the pre-operative and 2-year outcomes. Patients reported improved pain (p<0.001), function (p<0.001) and reduced stiffness (p<0.001) as measured by the WOMAC score. Patients had improved activity scores on the UCLA Active Score (P<0.001) with 53% reporting return to impact activity at 2 years. There was no osteolysis and the mean acetabular cup inclination angle was 41deg and the femoral component shaft angle was 137deg. No fractures were reported over but there was one sciatic nerve palsy with partial recovery. Two patients were revised; one at 3 months for pain due to a misdiagnosed back problem and another at 33 months for loosening of the acetabular component with delamination of the titanium ingrowth surface. CoC resurfacing at 2-years post-operation demonstrate promising results with satisfactory PROMS.
The number of revision arthroplasties being performed in the elderly is expected to rise, including revision for infection. The primary aim of this study was to measure the treatment success rate for octogenarians undergoing revision total hip arthroplasty (THA) for periprosthetic joint infection (PJI) compared to a younger cohort. Secondary outcomes were complications and mortality. Patients undergoing one- or two-stage revision of a primary THA for PJI between January 2008 and January 2021 were identified. Age, sex, BMI, American Society of Anesthesiologists grade, Charlson Comorbidity Index (CCI), McPherson systemic host grade, and causative organism were collated for all patients. PJI was classified as ‘confirmed’, ‘likely’, or ‘unlikely’ according to the 2021 European Bone and Joint Infection Society criteria. Primary outcomes were complications, reoperation, re-revision, and successful treatment of PJI. A total of 37 patients aged 80 years or older and 120 patients aged under 80 years were identified. The octogenarian group had a significantly lower BMI and significantly higher CCI and McPherson systemic host grades compared to the younger cohort.Aims
Methods
Femoral periprosthetic fractures are rising in incidence. Their management is complex and carries a high associated mortality. Unlike native hip fractures, there are no guidelines advising on time to theatre in this group. We aim to determine whether delaying surgical intervention influences morbidity or mortality in femoral periprosthetic fractures. We identified all periprosthetic fractures around a hip or knee arthroplasty from our prospectively collated database between 2012 and 2021. Patients were categorized into early or delayed intervention based on time from admission to surgery (early = ≤ 36 hours, delayed > 36 hours). Patient demographics, existing implants, Unified Classification System fracture subtype, acute medical issues on admission, preoperative haemoglobin, blood transfusion requirement, and length of hospital stay were identified for all patients. Complication and mortality rates were compared between groups.Aims
Methods
Hip resurfacing arthroplasty (HRA) is a bone conserving alternative to total hip arthroplasty. We present the early 1 and 2-year clinical and radiographical follow-up of a novel ceramic-on-ceramic (CoC) HRA in a multi-centric Australian cohort. Patient undergoing HRA between September 2018 and April 2021 were prospectively included. Patient-reported outcome measures (PROMS) in the form of the Forgotten Joint Score (FJS), HOOS Jr, WOMAC, Oxford Hip Score (OHS) and UCLA Activity Score were collected preoperatively and at 1- and 2-years post-operation. Serial radiographs were assessed for migration, component alignment, evidence of osteolysis/loosening and heterotopic ossification formation. 209 patients were identified of which 106 reached 2-year follow-up. Of these, 187 completed PROMS at 1 year and 90 at 2 years. There was significant improvement in HOOS (p< 0.001) and OHS (p< 0.001) between the pre-operative, 1-year and 2-years outcomes. Patients also reported improved pain (p<0.001), function (p<0.001) and reduced stiffness (p<0.001) as measured by the WOMAC score. Patients had improved activity scores on the UCLA Active Score (p<0.001) with 53% reporting return to impact activity at 2 years. FJS at 1 and 2-years were not significantly different (p=0.38). There was no migration, osteolysis or loosening of any of the implants. The mean acetabular cup inclination angle was 41.3° and the femoral component shaft angle was 137°. No fractures were reported over the 2-year follow-up with only 1 patient reporting a sciatic nerve palsy. There was early return to impact activities in more than half our patients at 2 years with no early clinical or radiological complications related to the implant. Longer term follow-up with increased patient numbers are required to restore surgeon confidence in HRA and expand the use of this novel product. In conclusion, CoC resurfacing at 2-years post-operation demonstrate promising results with satisfactory outcomes in all recorded PROMS.
The aim of this study was to assess the clinical and radiological outcomes of an antiprotrusio acetabular cage (APC) when used in the surgical treatment of periacetabular bone metastases. This retrospective cohort study using a prospectively collected database involved 56 patients who underwent acetabular reconstruction for periacetabular bone metastases or haematological malignancy using a single APC between January 2009 and 2020. The mean follow-up was 20 months (1 to 143). The primary outcome measure was implant survival. Postoperative radiographs were analyzed for loosening and failure. Patient and implant survival were assessed using a competing risk analysis. Secondary parameters included primary malignancy, oncological treatment, surgical factors, length of stay in hospital, and postoperative complications.Aims
Methods
Cement-in-cement revision of the femoral component represents a widely practiced technique for a variety of indications. In this study we compare the clinical and radiological outcomes of two polished tapered stems. From our prospectively collated database we identified all patients undergoing cement-in-cement revision from January 2005 – 2013 who had a minimum of two years follow-up. All cases were performed by the senior author using either an Exeter short revision stem or the C-stem AMT high offset No 1. Patients were followed-up annually with clinical and radiological assessment. Ninety-seven patients matched the inclusion criteria. There were 50 Exeter and 47 C-stem AMT components. There were no significant differences between the patient demographics in either group. Mean follow-up was 9.7 years. A significant improvement in OHS, WOMAC and SF-12 scores was observed in both cohorts. Leg lengths were significantly shorter in the Exeter group, with a mean of -4mm in this cohort compared to 0mm in the C-stem AMT group. One patient in the Exeter group had early evidence of radiological loosening. In total, 16 patients (15%) underwent further revision of the femoral component (seven in the C-stem AMT group and nine in the Exeter group). No femoral components were revised for aseptic loosening. There were two cases of femoral component fracture in the Exeter group. Our series shows promising long-term outcomes for the cement-in-cement revision technique using either the Exeter or C-stem AMT components. These results demonstrate that cement-in-cement revision using a double or triple taper-slip design is a safe and reliable technique when used for the correct indications.
Cement-in-cement revision of the femoral component represents a widely practised technique for a variety of indications in revision total hip arthroplasty. In this study, we compare the clinical and radiological outcomes of two polished tapered femoral components. From our prospectively collated database, we identified all patients undergoing cement-in-cement revision from January 2005 to January 2013 who had a minimum of two years' follow-up. All cases were performed by the senior author using either an Exeter short revision stem or the C-Stem AMT high offset No. 1 prosthesis. Patients were followed-up annually with clinical and radiological assessment.Aims
Methods
Acetabular cup orientation has been shown to be a factor in edge-loading of a ceramic-on-ceramic THR bearing. Currently all recommended guidelines for cup orientation are defined from static measurements with the patient positioned supine. The objectives of this study are to investigate functional cup orientation and the incidence of edge-loading in ceramic hips using commercially available, dynamic musculoskeletal modelling software that simulates each patient performing activities associated with edge-loading. Eighteen patients with reproducible squeaking in their ceramic-on-ceramic total hip arthroplasties were recruited from a previous study investigating the incidence of noise in large-diameter ceramic bearings. All 18 patients had a Delta Motion acetabular component, with head sizes ranging from 40 – 48mm. All had a reproducible squeak during a deep flexion activity. A control group of thirty-six patients with Delta Motion bearings who had never experienced a squeak were recruited from the silent cohort of the same original study. They were matched to the squeaking group for implant type, acetabular cup orientation, ligament laxity, maximum hip flexion and BMI. All 54 patients were modelled performing two functional activities using the Optimized Ortho Postoperative Kinematics Simulation software. The software uses standard medical imaging to produce a patient-specific rigid body dynamics analysis of the subject performing a sit-to-stand task and a step-up with the contralateral leg, Fig 1. The software calculates the dynamic force at the replaced hip throughout the two activities and plots the bearing contact patch, using a Hertzian contact algorithm, as it traces across the articulating surface, Fig 2. As all the squeaking hips did so during deep flexion, the minimum posterior Contact Patch to Rim Distance (CPRD) can then be determined by calculating the smallest distance between the edge of the contact patch and the true rim of the ceramic liner, Fig 2. A negative posterior CPRD indicates posterior edge-loading.Introduction
Methodology
Tendons are critical to mobility, and are susceptible to degeneration through injury and ageing. Type I collagen is the most abundant protein in vertebrates; it is the main structural protein of the extracellular matrix in numerous musculoskeletal tissues, including tendons. Type I collagen predominantly is a heterotrimer, which consists of two alpha-1 chains and one alpha-2 chain (α1)2(α2) encoded by the COL1A1 and COL1A2 genes, respectively. However, type I collagen can form homotrimers (α1)3 which are protease-resistant, and are associated with age-related musculoskeletal diseases, fibrotic and connective tissue pathologies. Transforming growth factor beta (TGFβ) enhances collagen (I) gene expression, is involved in tendon mechanobiology and repair processes, while its effect on homotrimer formation is unknown. Our aim is to investigate the relative expressions of collagen (I) α1 and α2 polypeptide chains in tenocytes (tendon fibroblasts) stimulated with TGFβ. Included RT-qPCR to measure the relative expression of COL1A1 and COL1A2 genes. [14C]-proline metabolic labelling was used to measure the expression of the collagen (I) α1 and α2 polypeptide chains. These techniques were performed in equine superficial digital flexor tendon (SDFT) tenocytes (n=3) and murine tail tendon tenocytes (n=3) with different concentrations of TGFβ (0.01 ng/ml-100 ng/ml).Introduction
Materials and Methods
Multiple organ failure (MOF) is a major cause of trauma mortality and morbidity. The role of surgical procedures in precipitating MOF remains unclear. Data on timing and duration of surgery was collated on 491 consecutive patients admitted to a Major Trauma Centre, who survived more than 48 hours and required Intensive Care Unit admission. MOF was defined according to the Denver Post Injury MOF Score, where MOF can occur only later than 48 hours after injury to exclude physiological derangements resulting from inadequate resuscitation. Overall, 268 patients (54.6%) underwent surgery within 48 hours of injury, with 110 (22.4%) requiring surgery within 6 hours of injury. Total mean intra-operative time (p=0.067) nor the need for an operation within the first 6 (p=0.069) or 48 hours (p=0.124) were associated with MOF development. Multivariate predictive modelling of MOF showed timing and duration of surgery had no significant predictive power for MOF development (Odds Ratio 0.72, 95% CI 0.47–1.10). Despite previous indication that early surgical intervention can precipitate MOF, current surgical strategy does not appear to impact MOF development.
Noise generation has been reported with ceramic-on-ceramic
articulations in total hip replacement (THR). This study evaluated
208 consecutive Delta Motion THRs at a mean follow-up of 21 months
(12 to 35). There were 141 women and 67 men with a mean age of 59
years (22 to 84). Patients were reviewed clinically and radiologically,
and the incidence of noise was determined using a newly described
assessment method. Noise production was examined against range of
movement, ligamentous laxity, patient-reported outcome scores, activity
level and orientation of the acetabular component. There were 143
silent hips (69%), 22 (11%) with noises other than squeaking, 17
(8%) with unreproducible squeaking and 26 (13%) with reproducible
squeaking. Hips with reproducible squeaking had a greater mean range
of movement (p <
0.001) and mean ligament laxity (p = 0.004), smaller
median head size (p = 0.01) and decreased mean acetabular component
inclination (p = 0.02) and anteversion angle (p = 0.02) compared
with the other groups. There was no relationship between squeaking
and age (p = 0.13), height (p = 0.263), weight (p = 0.333), body
mass index (p = 0.643), gender (p = 0.07) or patient outcome score
(p = 0.422). There were no revisions during follow-up. Despite the
surprisingly high incidence of squeaking, all patients remain satisfied
with their hip replacement. Cite this article:
The objective of this study was to determine the effectiveness of screening and successful treatment of methicillin-resistant We screened 5933 elective orthopaedic in-patients for MRSA at pre-operative assessment. Of these, 108 (1.8%) were colonised with MRSA and 90 subsequently underwent surgery. Despite effective eradication therapy, six of these (6.7%) had an SSI within one year of surgery. Among these infections, deep sepsis occurred in four cases (4.4%) and superficial infection in two (2.2%). The responsible organism in four of the six cases was MRSA. Further analysis showed that patients undergoing surgery for joint replacement of the lower limb were at significantly increased risk of an SSI if previously colonised with MRSA. We conclude that previously MRSA-colonised patients undergoing elective surgery are at an increased risk of an SSI compared with other elective patients, and that this risk is significant for those undergoing joint replacement of the lower limb. Furthermore, when an infection occurs, it is likely to be due to MRSA.
Both acute and chronic hamstring injuries are disabling injuries, and occur almost entirely to elite athletes. We report our experience in the management of injuries of this location. Twenty seven patients (29 injuries) were included in the present study. They completed a questionnaire detailing their pre-injury activity, injury mechanism, rehabilitation and a subjective assessment of their recovery. At clinical examination pain and hip motion were evaluated. Hamstring injuries predominantly affect males on the left side. Most procedures carried out were explorations with limited debridement and suture of the tendon. One third of patients felt they had returned to 100% of their pre-injury level, and 33% felt they had returned to 80–90% of their pre-injury level, the rest varied between <
20–80%. 45% gave a value of zero on the visual analogue pain scale independent of activity, those who gave a value above this had pain during active sports but not at rest. Early repair leads to a much better recovery of muscle function, especially when dealing with complete avulsions. Lesions to the origin of the hamstring can be successfully managed if a high suspicion for the condition exerted.
Flexion contracture in total knee arthroplasty (TKA) remains a challenge. Soft tissue management and additional bone resection are traditional options for flexion contracture correction. Our hypothesis was that the post implant computer aided measurements would not be significantly different to the extension angles measured at six weeks post-operatively in the follow-up clinic. One hundred continuous TKA were performed by a single consultant using the OrthoPilot® (BBraun, Aesculap) navigation system and Columbus implants. Of the group, 45 were male and 55 were female. Average age was 68 (range 49–87), mean BMI was 32.86 (22.26–51.86) and mean Oxford score preoperatively was 42 (range 21–56) and post-operatively 28 (range15–50). Data recorded at the preoperative assessment clinic included clinical flexion contracture and Oxford scores. Intra-operatively data were recorded using the navigation system. These included pre-operative flexion and extension angles, actual bone cuts of tibia and femur (both medial and lateral), postoperative correction of flexion and extension angles and soft tissue releases. At six weeks post operation, patients were seen in the follow clinic and clinical flexion contracture and Oxford score reassessed by the Arthroplasty outcome service. Measurements were grouped and comparisons were made using a Pearson Chi-square test. There was no relationship between post-implant extension angle measurements (by computer) and extension angles at six weeks (by goniometer) (p=0.682). Also, there was no relationship between pre-operative measurement angles collected at the pre-assessment (by goniometer) and the pre-implant angles measured on the table (by computer) (p=0.682). We found that BMI (up to 35) and postoperative Oxford scores were significantly related to the extension levels with values of (p=0.008) and (p=0.027) respectively. Pre-operative Oxford scores, pre-operative extension, amount of bony resection and soft-tissue releases did not show any significant relationship with the post-operative extension obtained at six weeks. The conclusions that we draw from this study are that there might be other factors that are likely to influence extension lag between the operation and the follow-up at six weeks. One of the factors that we could identify was the BMI. Attention to extensor lag is important because it leads to a poorer knee function, as indicated by the Oxford scores. Despite most of the post-implant measurement angles showing no extensor lag, about 20% of our patients still had more than five degrees flexion contracture at six weeks.
There is theoretical concern that volar plating has a disadvantage in cantilever bending when axially loaded dorsal to the neutral axis. This has implications for postoperative rehabilitation protocols and overall outcomes related to maintenance of reduction. Most recent biomechanical studies have compared volar locking plates to traditional dorsal non-locked plates. The purpose of this study was to compare the biomechanical stability of volar and dorsal locking plate fixation in a model of dorsally unstable distal radius fractures. Fourteen synthetic composite radii (Pacific Research Laboratories, Vashon, WA) were used for this study. A dorsally unstable, extra-articular distal radius fracture was simulated by creating a dorsal wedge-shaped defect in the distal metaphysis. Half of the specimens were plated dorsally (n=7) while the other half were plated volarly (n=7) with 2.4mm distal radius locking T-plates (Synthes, Canada). Each specimen was loaded axially in five different positions: central (along the neutral axis of the radius) as well as dorsal, volar, radial and ulnar to the neutral axis using a MTS Sintech 1/G materials testing machine (MTS Systems, Eden Prairie, MN). The plated radii were loaded to 100 N in each position simulating physiological loading during normal range of motion. The main outcome measure was construct stiffness of the plate-bone system (slope of load-displacement curve) for all five loading positions. Construct stiffness with dorsal locking plates was seven times greater than volar locking plates when dorsally loaded (p <
0.001), 60% greater when centrally loaded (p = 0.055) and 35% greater when volarly loaded (p = 0.029). There was no significant difference in stiffness with any other loading configurations. The stability of dorsal locking plate fixation is superior to volar locking plate fixation in the setting of large dorsal defects in the distal radius. This is applicable to both fractures with dorsal comminution and dorsal opening-wedge distal radial osteotomies. Further clinical investigation is needed to compare functional outcomes and complication rates between modern dorsal and volar locking plate techniques.
Two of the major complications of total hip and knee arthroplasty is periprosthetic infection and aseptic loosening. The serum marker Procalcitonin (PCT) has been shown to be a sensitive indicator of bacterial infection, but very little is known of its behaviour in Orthopaedic practice. The diagnosis of periprosthetic infection still remains a difficult diagnosis. A prospective study over 6 months of 59 patients undergoing either primary total hip or knee arthroplasty was performed, which included 32 hips. The mean age was 70 years. There were no exclusion criteria. Serum blood samples for PCT, CRP, ESR and WCC were taken pre- operatively and on days 1, 3 and 5 post- operatively. Patient records were reviewed after their routine 6 week follow- up. There was no clinical suspicion of infection at this stage, or during their hospital stay. Fifty patients (85%) had PCT concentrations within the normal range (<
0.5ng/ml) on all 4 days, and only 5 recorded a value >
1.0ng/ml. Only 1 patient had an elevated level on day 5. The other markers all showed sporadic elevation over the 3 post- operative days The usefulness of PCT in diagnosing surgical infection has been frequently researched in cardio- thoracic and abdominal surgery. However, there is debate as to what cut- off value should represent infection, ranging from 1– 10ng/ml. This is largely because the natural acute phase response caused by these operations elevates PCT levels. This study convincingly shows that PCT, unlike the routine inflammatory markers, is not significantly stimulated by primary hip and knee arthroplasty. This would imply that PCT may be useful in diagnosing periprosthetic infection. A large multicentre study involving patients undergoing revision surgery would help validate this assumption.
Our cadaveric biomechanical study has demonstrated evidence to suggest that commercially available removable cast boots do provide the same reduction of force on a first MTP joint arthrodesis site, during the early post operative period, as a traditional fiberglass cast. This study compares the effectiveness of three common models of walking boots to a fiberglass cast in protecting an arthrodesis of the first metatarsophalangeal (MTP) joint in the early post-operative period. First MTP joint arthrodesis is commonly performed for various clinical problems. Weight bearing is encouraged post operatively, however the arthrodesis site must be protected from excessive forces until bony union is achieved. Two cadaveric models of a 1st MTP joint arthrodesis were prepared with a strain gauge placed at the joint, which provided a measure of the bending moment across the fusion site. Walking was simulated by applying a force to the sole of the cadaver foot at multiple positions, from the heel to the toe, representing the stages of gait from heel strike to toe off. Loading trials were performed using each of the walking boots and a fiberglass cast, with the moments across the joint compared. For both specimens, the “Walkabout” by Smith &
Nephew had the lowest mean moment. Specimen one showed that the “Walkabout” and “Sampson Walker” were both better than the “Equalizer” and fiberglass cast (p<
0.05). Specimen two showed that the “Walk-about” was better than all others (P<
0.05). Also, for both specimens, the “Walkabout” by Smith &
Nephew had the smallest absolute maximum moment (P<
0.05). Our study has shown that removable cast boots do provide the same, if not more, reduction of force on a first MTP joint arthrodesis site as a traditional cast.
Intramedullary tibial nailing was performed in ten paired cadavers and the insertion of a medial-to-lateral proximal oblique locking screw was simulated in each specimen. Anatomical dissection was undertaken to determine the relationship of the common peroneal nerve to the cross-screw. The common peroneal nerve was contacted directly in four tibiae and the cross-screw was a mean of 2.6 mm (1.0 to 10.7) away from the nerve in the remaining 16. Iatrogenic injury to the common peroneal nerve by medial-to-lateral proximal oblique locking screws is therefore a significant risk during tibial nailing.
We describe our early experience with the implantation of the first consecutive 231 primary Birmingham Hip resurfacings. At a mean follow up of 33 months, survivorship was 99.14 %, with revision in one patient for a loose acetabular component and one unrelated death. Mean Harris Hip score improved from a mean of 62.54 ( Range : 8–92) to 97.74. (Range: 61 – 100) Mean flexion improved from a mean of 91.52°, ( Range : 25° –140°) to a mean 110.41°. ( Range : 80° – 145°) 1 patient presented at 6 weeks post resurfacing with pain and no history of trauma. An undisplaced fracture of the superior femoral neck was seen, which healed with a period of non-weight bearing. 96.94% of patients rated their prosthesis as good / excellent, the remainder rated it good/fair.
220 consecutive hip resurfacing procedures were reviewed at a minimum of two years follow up to assess the incidence of heterotopic ossification and its effect on function and clinical outcome. We also reviewed the pre-operative diagnosis, gender and previous surgery. The overall percentage of heterotopic ossification was 58.63%. The incidence of Brooker 1 was 37.27%, Brooker 2 was 13.18% and Brooker 3 was 8.18%. Male osteoarthritics had the highest incidence of heterotopic bone formation. Three males underwent excision of heterotopic bone, two for pain and stiffness and one for decreased range of movement. Both antero-posterior and lateral radiographs were reviewed for evidence of heterotopic bone formation. 12.7% had no evidence of heterotopic bone formation on one view but clearly had on the second view. Overall we found no evidence that heterotopic bone formation affected the clinical or functional outcome of the hip resurfacing at a mean of 3 years follow up.
We describe the experience with the first consecutive 230 Birmingham hip resurfacings at our centre. At a mean follow-up of three years (25 to 52 months) survivorship was 99.14% with revision in one patient for a loose acetabular component and one death from unrelated causes. One patient developed a fracture of the femoral neck at six weeks which united unremarkably after a period of non-weight-bearing. The Harris hip score improved from a mean of 62.54 (8 to 92) to 97.74 (61 to 100). The mean flexion improved from 91.52° (25 to 140) to 110.41° (80 to 145). Most patients (97%) considered the outcome to be good or excellent. Our preliminary experience with this implant is encouraging and the results are superior to the earlier generation of resurfacings for the same length of follow-up.
A prospective consecutive series of uncemented, hydroxyapatite coated primary hip replacements utilizing two different types of alumina ceramic inserts and alumina ceramic heads is reported. Clinical and radiological results together with complications and reoperations are detailed. 193 hips followed up to 39 months using the Secur fit cup with ABC liner (Stryker). 40 hips using the Trident AD shell with the Trident titanium wrapped liner are reported up to 18 months. Clinical scores (Harris and Postel Merle D’Aubigne) are similar to metal polyethylene at early review. SF 12 physical scores improved post operation. 100% bony ingrowth was seen radiologically (Engh and ARA scores). Liner rim surface chips on insertion were seen in 1.4% of the ABC liners and none occurred after the 20th hip. No chips were seen in the Trident liners. One ABC liner sustained extensive surface rim chips in a heavy fall at 24 months. This is the first report of such a liner fracture. One Secur fit ABC cup was revised for recurrent subluxation. The importance of early revision of ceramic fractures and the re use of shells is discussed. The addition of a titanium sandwich wrap to the ceramic liner is likely to eliminate the early chips.