Revision of a fractured uncemented revision stem using a custom designed punch and retrograde through-knee approach.

We report a unique case of a fractured modular cobalt chromium connection taper Revitan (Zimmer, Warsaw, IN) revision prosthesis. Macroscopic examination revealed a fracture at the diaphyseal-metaphyseal junction of this modular component. This report highlights that fractures can still occur with modern modular prostheses. We are not aware of any published failures of the Revitan revision prosthesis. We also describe a unique method of retrieval for a broken well fixed uncemented femoral stem, using a custom designed extraction instrument via a through-knee approach.

Early metallosis-related failure after total knee replacement: a report of 15 cases.

Metallosis is a rare cause of failure after total knee replacement and has only previously been reported when there has been abnormal metal-on-metal contact. We describe 14 patients (15 knees) whose total knee replacement required revision for a new type of early failure caused by extensive metallosis. A modification of a cementless rotating platform implant, which had previously had excellent long-term survival, had been used in each case. The change was in the form of a new porous-beaded surface on the femoral component to induce cementless fixation, which had been used successfully in the fixation of acetabular and tibial components. This modification appeared to have resulted in metallosis due to abrasive two-body wear. The component has subsequently been recalled and is no longer in use. The presentation, investigation, and findings at revision are described and a possible aetiology and its implications are discussed.

Lateral unicompartmental knee replacement: fixed or mobile bearing?

Between May 2001 and May 2003, 233 consecutive Preservation unicompartmental knee replacements (UKR) were performed. Of these, 30 were lateral UKRs (13%) performed in 12 men and 16 women (2 bilateral cases) with a mean age of 67 years (range 36-93 years). A metal-backed mobile bearing tibial component was used in 13 knees and an all-polyethylene fixed bearing tibial component in 17 knees. The patients were reviewed prospectively at 1 and 2 years. The 2 year results show no difference in range of motion or function between the mobile and fixed bearing versions of the Preservation knee when used on the lateral side. There were three early revisions, all in the mobile bearing group.

Limb alignment in computer-assisted minimally-invasive unicompartmental knee replacement.

Twenty patients underwent simultaneous bilateral medial unicompartmental knee arthroplasty. Pre-operative hip-knee-ankle alignment and valgus stress radiographs were used to plan the desired post-operative alignment of the limb in accordance with established principles for unicompartmental arthroplasty. In each patient the planned alignment was the same for both knees. Overall, the mean planned post-operative alignment was to 2.3 degrees of varus (0 degrees to 5 degrees ). The side and starting order of surgery were randomised, using conventional instrumentation for one knee and computer-assisted surgery for the opposite side. The mean variation between the pre-operative plan and the achieved correction in the navigated and the non-navigated limb was 0.9 degrees (sd 1.1; 0 degrees to 4 degrees ) and 2.8 degrees (sd 1.4; 1 degrees to 7 degrees ), respectively. Using the Wilcoxon signed rank test, we found the difference in variation statistically significant (p < 0.001). Assessment of lower limb alignment in the non-navigated group revealed that 12 (60%) were within +/- 2 degrees of the pre-operative plan, compared to 17 (87%) of the navigated cases.Computer-assisted surgery significantly improves the post-operative alignment of medial unicompartmental knee arthroplasty compared to conventional techniques in patients undergoing bilateral simultaneous arthroplasty. Improved alignment after arthroplasty is associated with better function and increased longevity.

Cemented or uncemented hemiarthroplasty for displaced intracapsular femoral neck fractures.

The aim of this study was to establish whether or not to cement the hemiarthroplasty for displaced intracapsular femoral neck fractures in the elderly. Consecutive patients treated by hemiarthroplasty in adjacent hospitals were reviewed. The same monoblock prosthesis was used; in hospital A they were uncemented (121 patients), and in hospital B they were cemented (123 patients). Notes were reviewed retrospectively. Surviving patients (50 and 56 respectively) were assessed prospectively for pain and functional ability using validated scoring systems. Follow-up was 32-36 months. Patient demographics were similar. Fewer of the cemented group had been revised or were awaiting revision ( P=0.036). There was no difference in general complication or mortality rates. There was a highly statistically significant greater deterioration in pain ( P=0.003), walking ability ( P=0.002), use of walking aids ( P=0.003) and activities of daily living ( P=0.009) in the uncemented group. Our findings support the use of cemented hemiarthroplasty in the elderly.

A survey of the treatment of displaced intracapsular femoral neck fractures in the UK.

A survey was undertaken to investigate the treatment of displaced intracapsular femoral neck fractures across the UK. The usual practice at 223 hospitals was recorded for two groups of patients, active and frail. Management of stereotyped fractures, in similar patients, varied between hospitals. There was also variation between specialists within some hospitals: two or more of the alternative methods of treatment were in routine use for active patients at 22% of hospitals and for frail patients at 27%. Overall, for active patients, bipolar hemiarthroplasty was undertaken at 41% of hospitals, internal fixation at 37%, unipolar hemiarthroplasty at 32% and total hip replacement at 16%. Cemented prostheses were used in 74% of arthroplasties for active patients. For frail patients, hemiarthroplasty with an Austin Moore or Thompson prostheses was undertaken at 94% of hospitals; bipolar prostheses were used at 8%; internal fixation was undertaken at 1%. Cement was used in 46% of hemiarthroplasties. These findings indicate a lack of consensus in aspects of the treatment of displaced intracapsular femoral neck fractures and are likely to reflect difficulties in determining "best practice."

Cemented or uncemented hemiarthroplasty for displaced intracapsular fractures of the hip--a systematic review.

Displaced intracapsular hip fractures are often treated by hemiarthroplasty, with or without cement. The aim of this study is to perform a systematic review of the literature to establish whether this influences the outcome. A comprehensive search of the English language world literature of all studies comparing cemented with uncemented hemiarthroplasty was performed. Eighteen publications addressing this issue were identified. Three were excluded from review because of poor study design and non-comparability of groups. Of the remainder, few were suitable for statistical analysis, therefore a qualitative comparison of results was carried out. The majority of studies suggested a lower revision rate, less thigh pain and better mobility in-patients in whom the prosthesis was cemented. Cemented hemiarthroplasty may be associated with increased operative time and blood loss. There appears to be no difference in general complication, or mortality rates after 3 months, between the two groups. Radiographic differences were variable and did not correlate with clinical findings. We conclude, the literature tends to support the use of cement in hemiarthroplasty for displaced intracapsular femoral neck fractures. Further prospective randomised studies are required to resolve the issue.

Effects of cold and compression dressings on early postoperative outcomes for the arthroscopic anterior cruciate ligament reconstruction patient.

Efforts to minimize the morbidity of anterior cruciate ligament (ACL) reconstruction include the use of cryotherapy and/or compressive dressings in the immediate postoperative period. We undertook the present study to determine if the alleged benefits of the Cryo/Cuff, which combines these modalities, are more attributable to its compressive effect rather than cold application. Seventy-eight patients admitted for primary endoscopic ACL reconstruction using a bone-patella tendon-bone autograft were randomized to receive Cryo/Cuff compressive dressings postoperatively. Forty subjects (Group 1) had the cuff applied with continuous circulating ice water using the Autochill device, while 38 others (Group 2) received the cuff with room temperature water. Cases were performed as inpatients and all subjects were administered intravenous morphine postoperatively via a patient-controlled infusion pump for the first 24 postoperative hours. At baseline, the groups were well matched in age, sex, duration of symptoms, operative time, and associated meniscal surgery. No significant difference between groups was detected with respect to length of hospitalization, Hemovac knee drainage, oral and intravenous narcotic requirement, or subjective pain as measured by a visual analog scale. No apparent complications related to the use of the Cryo/Cuff dressings were noted. The clinical effect of the Cryo/Cuff in this study was not influenced by the use of continuous ice water vs. room temperature water. Further study should focus on variations in compression to evaluate the clinical impact of this device.

Biodegradable rods in adult osteochondritis dissecans of the knee.

Symptomatic osteochondritis dissecans of the knee in skeletally mature patients does not follow a predictable natural history and there has been a trend toward internal fixation of the unstable fragment(s) where possible. Biodegradable implants are enticing for intraarticular use: implant removal is unnecessary and its degradation potentially allows a gradual shift of loading stress to the fracture site. Nine patients with a mean age of 18.6 years (range, 14-23 years) deemed skeletally mature by plain film radiography underwent internal fixation of fragments by 2-mm self reinforced polylactic rods. Six procedures were completed arthroscopically and three required arthrotomy. All fragments were of the medial femoral condyle. The procedure was tolerated well although three patients had early postoperative serosanguinous effusions develop that did not recur after one aspiration. At a mean followup of 33 months (range, 24-54 months), eight fragments radiographically were united whereas one remained ununited at 26 months, accounting for the one poor result in this series. Seven patients had good to excellent results according to Hughston's criteria and were satisfied with the procedure. One of these seven patients had a spontaneous effusion develop at 5 months that did not recur after aspiration and intraarticular steroid injection. Severe, unremitting synovitis did not occur in any patient. Internal fixation of osteochondritis dissecans of the knee with biodegradable polylactic rods provided satisfactory control of symptoms in the short term and resulted in radiographically stable lesions in eight of nine patients. These rods may be suited best for fragmented lesions with intact articular cartilage as an adjunct to drilling.

Failure strengths of suture versus biodegradable arrow for meniscal repair: an in vitro study.

Advances in our understanding of meniscal function and consequences of menisectomy have spawned meniscal repair techniques that yield success rates approaching 90% in properly selected patients. Biodegradable implants have been fashioned for meniscal fixation to simplify the technique and minimize neurovascular complications. We performed the current study to determine the in vitro biomechanical behavior of the BIOFIX Meniscal Arrow, a polylactic acid tack developed for meniscal repair. Eight pairs of menisci were harvested from cadaveric knees kept frozen before testing. Peripheral vertical tears were created in the posterior horn of all menisci, and each was subsequently repaired using a vertical loop suture of 2-0 Ethibond and a Meniscal arrow. Ultimate load to failure of each method was determined on a Hounsfield H25KM Universal Testing machine. The mean failure load for the suture group was 58.3 N compared with the Arrow group mean of 29.6 N (P < .001). All sutures failed by rupture at the knot but did not pull through the meniscus. All but one of the arrows failed by pulling out of the meniscus. The Arrows also permitted gapping at the repair site at considerably lesser loads than the sutures subject to strain. The concept of a biodegradable tack is appealing. Vertical loop sutures should be the standard by which their biomechanical performance is judged. We suggest modifications to the Arrow design that could enhance the fixation strength of this implant.

Femoral bone plug recession in endoscopic anterior cruciate ligament reconstruction.

Graft tunnel mismatch is a constant challenge in endoscopic ACL reconstruction with bone-patella tendon-bone allograft. Strategies for addressing this situation on the tibial side which include staple or suture fixation may compromise the postoperative pullout strength of the graft. We describe our technique for recession of the femoral bone plug as a solution to this problem and present our preliminary experience in a series of 100 consecutive patients followed-up to 1 year. Interference screw fixation was consistently achieved in both tunnels and recession did not influence anterior-posterior displacement by KT arthrometry.

Direct measurement of hoop strains in the intact and torn human medial meniscus.

OBJECTIVE: To measure the circumferential or hoop strains generated in the medial meniscus during loading of the knee joint and to examine the effect of longitudinal and radial tears in the meniscus on these strain values. DESIGN: An in vitro investigation measuring the circumferential strains in the medial menisci of cadaveric human knees as they were loaded in a materials testing machine. BACKGROUND: The menisci transmit approximately 50% of the load through the knee, the rest being transmitted by direct contact of the articular cartilage. Damage to the menisci will alter the pattern of load transmission as will meniscectomy. This study examined the changes in the mechanics of the meniscus in situ as a result of simulated tears to assess the effect of its load carrying capacity and the implications of surgery to remove part or all of a damaged meniscus. METHODS: Nineteen human cadaveric knees were tested. Windows were made in the joint capsule and strain gauges inserted into the anterior, middle and posterior sections of the medial meniscus. The knees were then loaded to three times body weight at speeds of 50 and 500 mm/min, with the knee joint at 0 degrees and 30 degrees of flexion. The tests were repeated following the creation of a longitudinal or a radial tear in the meniscus. RESULTS: The intact menisci showed significantly less strain in the posterior section compared to the anterior and middle sections (P < 0.003, with strains of 1.54%, 2.86% and 2.65% respectively). With a longitudinal tear this pattern changed with strains decreasing anteriorly and increasing posteriorly. There were also significant differences at different angles of knee joint flexion not seen in the intact meniscus. 50% radial tears reduced the strains anteriorly whilst a complete radial tear completely defunctioned the meniscus. CONCLUSIONS: This study has shown that there are significantly different hoop strains produced in different sections of the medial meniscus under load and the patterns of strain distribution are disturbed by meniscal tears. RELEVANCE: These results provide important data for mathematical models which must include non-uniform behaviour. They also have implications for the surgical management of torn menisci. Undamaged portions should be preserved and the integrity of the circumferential fibres maintained to ensure the menisci retain a load bearing capability.

Magnetic resonance imaging of the knee: assessment of effectiveness.

OBJECTIVES: To quantify how magnetic resonance imaging (MRI) influences clinicians' diagnoses, diagnostic confidence and management plans in patients with knee problems. To investigate whether these changes can bring about an improvement in health. METHODS: This was a prospective observational study on all patients referred to a regional unit for MRI of the knee over a 6-month-period. Data on diagnosis, diagnostic confidence and proposed management before MRI was compared with diagnoses and actual management after MRI. In addition, short form 36 item (SF-36) health survey data was collected at referral and again 6 months later. RESULTS: Three hundred and thirty-two patients were entered into the study. MRI led to previously unsuspected diagnosis in 69 of 269 patients with available data. When MRI confirmed the clinical diagnosis, significant improvements in clinicians' diagnostic confidence were found (P < 0.01 for medical meniscus, P < 0.05 lateral meniscus, P < 0.05 anterior cruciate). MRI led to a change in management in 180 (63%) of 288 patients (where data available). There was a significant shift away from surgical management after MRI (P < 0.01). SF-36 results were available in 206 patients. There was a significant improvement over time in five of the eight SF-36 scales (four at P < 0.001, one at P < 0.01). CONCLUSIONS: Magnetic resonance imaging significantly influences clinicians' diagnoses and management plans. These patients, examined by MRI, also recorded an improvement in health related quality of life.

The use of cold therapy in the postoperative management of patients undergoing arthroscopic anterior cruciate ligament reconstruction.

In this prospective, randomized study we assessed the use of cold therapy after arthroscopic anterior cruciate ligament reconstruction. Seventy-one patients were randomly allocated, without the knowledge of the single surgeon, to one of three groups: Group I had an ice water-filled CryoCuff fitted in the operating theater after surgery, Group II had room temperature water in the CryoCuff, and Group III patients had no CryoCuff. Patients were well matched for age, sex, and associated surgery. An independent observer measured blood loss, analgesic use, range of motion, and visual analog pain scores postoperatively. There were no differences between any of the three groups regarding the variables measured. The use of cold therapy devices as an adjunct to the postoperative management of these patients must be questioned.

Radiographic changes in the knee after meniscal transplantation. An experimental study in a sheep model.

Meniscal transplantation has been suggested as an alternative to total meniscectomy, which is now known to lead to long-term osteoarthritic degeneration of the knee joint. To evaluate the success of meniscal transplantation, we divided 28 sheep knees into 4 groups: total meniscectomy, allograft, autograft, and control. After a mean postoperative time of 21.4 months, we radiographed the excised knee joints in a loaded state and graded the radiographs for osteoarthritic changes. The knees with meniscectomies, allografts, and autografts showed significantly more degenerative changes than the control knees. However, there were no statistically significant differences between these three groups. The results of this study suggest that meniscal allograft transplantation does not protect the knee against degenerative changes.

Comparative audit of blood transfusion during war and peace in Sarajevo.

A comparative study was made between 146 patients receiving blood transfusion at the State Hospital, Sarajevo, in a 3-month period of peace (group 1) and 250 patients receiving transfusions in a 3-month period of war (group 2). In group 1, trauma accounted for only 7% of transfusions while it accounted for 99% in group 2. The threshold for transfusion was increased in war and the mean pretransfusion haematocrit in group 2 was 21%, compared with 27% in group 1 (P < 0.001). Less blood was also transfused per patient in war with a mean transfusion volume of 1.1 units in group 2 compared with 2.6 units in group 1 (P < 0.001). The reasons and justification for such a conservative transfusion practice in a besieged city are discussed.