Radial head arthroplasty for radial head fractures: a clinical and radiological comparison of monopolar and bipolar radial head arthroplasty at a mean follow-up of 6 years.

PURPOSE: The purpose of this study was to compare clinical and radiographic outcomes of bipolar and monopolar radial head arthroplasty in treatment of radial head fracture at a mean follow-up of 6 years. METHODS: A retrospective multicentre cohort study of 30 patients treated for unreconstructable radial head fractures. Patients were treated either with a cemented bipolar or an uncemented monopolar radial head arthroplasty. All patients included were evaluated with patient-rated outcome questionnaire, physical examination, and radiographic evaluation at a mean of 6 years (range, 2-12 years) postoperatively. RESULTS: There was no statistical difference in QuickDASH between the bipolar or monopolar groups. The majority of patients had no to little pain during rest. Neither flexion nor extension of the injured arm was significantly affected by the type of prosthesis. None of the patients in the bipolar group had any secondary surgery at the time of follow-up. In the monopolar group, four patients required removal of the arthroplasty. Signs of ulnohumeral degenerative changes were seen in the majority of patients in both groups (55% in the monopolar group, 92% in the bipolar group). CONCLUSION: In this retrospective cohort study comparing a bipolar and a monopolar radial head arthroplasty for treatment of radial head fractures, we found comparable functional outcome but more revision procedures in the monopolar group at a mean follow-up of 6 years.

High prevalence of rotator cuff tears in a population who never sought for shoulder problems: a clinical, ultrasonographic and radiographic screening study.

BACKGROUND: This study was designed to investigate the prevalence of rotator cuff tears in a population who had never sought for symptoms from their shoulders. The aim was to see whether there is a correlation between dysfunction and the presence of cuff tears seen with ultrasonography or radiology. MATERIALS AND METHODS: Clinical assessment with constant score, ultrasound and radiographic examination was done on 106 voluntary subjects (212 shoulders). There were 52 men and 54 women with a median age of 66 years. The correlations between complaints, cuff tears, constant score, ultrasound and radiological findings were calculated. RESULTS: Of 106 subjects, 64 (60%) had shoulder problems. The prevalence of full-thickness cuff tears was 30% (21% of all the 212 shoulders). 61% of the shoulders with full-thickness tears had symptoms compared to 33% of the shoulders without tears. The constant score was lower in shoulders with full-thickness tears. Partial tears or acromioclavicular degeneration had no impact on shoulder complaints or constant score. The subacromial index was lower for shoulders with full-thickness tears. Patients with primary osteoarthritis had a lower acromion index than patients with full-thickness tears. CONCLUSION: The prevalence of shoulder complaints and/or cuff tears was high in this population, which had never sought medical care for shoulder problems. Only full-thickness tears had an impact on shoulder function and constant score. Partial-thickness tears and degenerative changes in the acromioclavicular joint may be considered as age-related changes. The subacromial index can be used as a predictor for full-thickness cuff tears. LEVEL OF EVIDENCE: Level III, cross-sectional study, prevalence study.

Arthroplasty as primary treatment for distal humeral fractures produces reliable results with regards to revisions and adverse events: a registry-based study.

BACKGROUND: Primary prosthetic replacement has become an accepted method for the treatment of complex distal humeral fractures. The present study investigated implant survival and adverse events related to this procedure based on available Swedish registries and examined the completeness of the Swedish Elbow Arthroplasty register. MATERIALS AND METHODS: Patients treated in Sweden with a primary elbow replacement due to a distal humeral fracture between 1999 and 2014 were identified through 3 different registries: The Swedish Elbow Arthroplasty Register, National Board of Health and Welfare inpatient register, and local registries of all orthopedic departments. Prosthetic survival was examined using Cox regression analysis with Kaplan-Meier plots. Adverse events, defined as medical treatment of the affected elbow besides revision, were analyzed separately. The study included 406 elbows in 405 patients, and no register was complete. RESULTS: Implant survival at 10 years was 90% (95% confidence interval, 85%-96%), but only 45 patients had an observation time of 10 years or more because 46% of the patients had died, resulting in a mean observation time of 67 (standard deviation, 47) months. An increase in the use of hemiarthroplasties and a proportional decrease of total elbow arthroplasties was detected. There were 18 revisions (4%), and 26 patients (6%) experienced an adverse event, of whom 16 (4%) required surgery. The completeness of the Swedish Elbow Arthroplasty Register regarding primary arthroplasty was 81%. CONCLUSION: Primary arthroplasty as treatment of distal humeral fractures produces reliable results with regards to revisions and other adverse events.

Lower age increases the risk of revision for stemmed and resurfacing shoulder hemi arthroplasty.

Background and purpose - The number of patients where shoulder hemiarthroplasty (SHA) is an option is still substantial. Descriptive analyses performed by the Swedish Shoulder Arthroplasty Registry (SSAR) showed that while patients receiving SHA designs, i.e. resurfacing hemi (RH) and stemmed hemi (SH), reported similar shoulder functionality and quality of life, the revision rate for RH (12%) was larger than for SH (6.7%); this difference was studied. Patients and methods - All primary SHA (n = 1,140) for OA reported to SSAR between 1999 and 2009 were analyzed regarding risk factors for revision and PROM outcome, 950 shoulders with primary OA (POA), and 190 secondary OA (SOA). Mean age was 67.4 years (SD 10.8). PROM including WOOS and EQ-5D were collected at 5 years, until December 31, 2014. Results - 76/950 prostheses because of POA and 16/190 prosthesis because of SOA were revised. Age at primary surgery was the main factor that influenced the risk of revision, lower age increased the risk of revision, and was also the explanation for the difference between SH and RH. We also found that SH and RH had similar outcomes measured by PROM, but the POA group had higher scores than the SOA group with a clinically relevant difference of 10% in WOOS. Interpretation - The risk of revision for SH and RH is similar when adjusted for age and does not depend on primary diagnosis or sex. A lower age increases the risk of revision. Patients suffering from POA experience better shoulder functionality than SOA patients irrespective of implant type.

High incidence of periprosthetic joint infection with propionibacterium acnes after the use of a stemless shoulder prosthesis with metaphyseal screw fixation - a retrospective cohort study of 241 patients.

BACKGROUND: A stemless shoulder prosthesis with humeral metaphyseal screw fixation was introduced in order to save bone-stock and to facilitate reconstruction of biomechanics (Eclipse®). The aim of this study was to analyze whether the risk of infection is different with this implant compared to conventional shoulder prosthesis. METHODS: Two hundred and forty-one patients (54.8% females) were operated with a shoulder arthroplasty and followed for median 2.0 (0.1-5.7) years. One hundred and two (42.3%) had received an Eclipse® prosthesis, the remaining patients were operated with other implants. There was an overrepresentation of males in the Eclipse® group (63.7% males) when compared with the control group (31.7% males). RESULTS: In the Eclipse® group 10 (9.8%) patients developed a periprosthetic joint infection, as opposed to 1 (0.7%) in the control group. The most common bacteria was Propionibacterium acnes. Unadjusted infection-free survival after 4 years was 88.8% (CI 82.5-95.7) for Eclipse® patients and 95.7% (CI 87.7-100.0) for controls (p = 0.002). After adjustment for age, gender, diagnosis, and type of shoulder prosthesis (total or hemi), the risk ratio for revision due to infection was 4.3 (CI 0.5-39.1) for patients with the Eclipse® prosthesis. CONCLUSIONS: Deep infections seem to be more common after the use of the metaphyseally fixed Eclipse® prosthesis than after conventional shoulder implants, but a predominance of male gender and younger age in the Eclipse group may have biased our findings. Future studies on larger cohorts and in vitro investigations on bacterial adherence and biofilm formation are needed. TRIAL REGISTRATION: The study was conducted in accordance with the Helsinki Declaration. The local ethics board (Regionala Etikprövningsnämnden Stockholm) approved the study (Approval number 2015/1590-31, date of issue 2015-10-14). Retrospectively registered.

Primary anterior dislocation of the shoulder: long-term prognosis at the age of 40 years or younger.

PURPOSE: We describe the long-term prognosis in 257 first-time anterior shoulder dislocations (255 patients, aged 12-40 years) registered at 27 Swedish emergency units between 1978 and 1979. METHODS: Half the shoulders were immobilised for 3-4 weeks after repositioning. Follow-ups were performed after two (questionnaire), five (questionnaire), 10 (questionnaire and radiology) and 25 (questionnaire and radiology) years in 227 patients (229 shoulders). Twenty-eight patients died during the 25 years of observation. RESULTS: Early movement or immobilisation after the primary dislocation resulted in the same long-term prognosis. Recurrences increased up to 10 years of follow-up, but, after 25 years, 29 % of the shoulders with ≥2 recurrences appeared to have stabilised over time. Arthropathy increased from 9 % moderate to severe and 11 % mild at 10 years, to 34 % moderate to severe and 27 % mild after 25 years. Alcoholics had a poorer prognosis with respect to dislocation arthropathy (P < 0.001). Age <25 years and/or bilateral instability represent a poorer prognosis, where stabilising surgery is necessary in every second shoulder. Fracture of the greater tuberosity means a good prognosis, and we have found no evidence that athletic activity, gender, a Hill-Sachs lesion and minor rim fractures had any prognostic impact. During the 25 years in which these patients were followed, 28/255 died (11 %), representing a mortality rate (SMR) that was more than double that of the general Swedish population (P < 0.001). CONCLUSION: Almost half of all first-time dislocations at the age of <25 years will have stabilising surgery and two-thirds will develop different stages of arthropathy within 25 years.

Risk of arthropathy after the Bristow-Latarjet repair: a radiologic and clinical thirty-three to thirty-five years of follow-up of thirty-one shoulders.

BACKGROUND: Transfer of the coracoid (Bristow-Latarjet [B-L]) is used to stabilize anterior shoulder instability. We report the long-term results of our first 31 operations with this method. MATERIALS AND METHODS: Thirty-six patients (mean age, 26.7 years) had a B-L repair from 1977 to 1979. Five patients died, and during 2012 to 2013, the remaining 31 shoulders had a follow-up with questionnaire, physical examination, Western Ontario Shoulder Instability Index, Subjective Shoulder Value, Subjective Assessment of Shoulder Function, subjective assessment of loss of motion, and radiologic imaging. RESULTS: One patient required revision surgery because of recurrence and another because of repeat dislocation. Six patients reported subluxations. Eighteen patients (58%) were very satisfied, and 13 (42%) were satisfied. The mean Western Ontario Shoulder Instability Index score (100 possible) was 85, and the median score was 93. According to Samilson-Prieto classification of arthropathy of the shoulder, 39% were classified as normal, 27% as mild, 23% as moderate, and 11% as severe. The classification of arthropathy varied with observers and radiologic views. Age younger than 22 years at the primary dislocation meant less arthropathy at follow-up (P = .045). CONCLUSION: The degree of arthropathy 33 to 35 years after the B-L repair seems to follow the natural history of shoulder dislocation with respect to arthropathic joint degeneration. Postoperative restriction of external rotation does not increase later arthropathy.

A review of national shoulder and elbow joint replacement registries.

BACKGROUND: The aim was to review the funding, organization, data handling, outcome measurements, and findings from existing national shoulder and elbow joint replacement registries; to consider the possibility of pooling data between registries; and to consider wether a pan european registry might be feasible. MATERIALS AND METHODS: Web sites, annual reports, and publications from ongoing national registries were searched using Google, PubMed, and links from other registries. Representatives from each registry were contacted. RESULTS: Between 1994 and 2004, 6 shoulder registries and 5 elbow registries were established, and by the end of 2009, the shoulder registries included between 2498 and 7113 replacements and the elbow registries between 267 and 1457 replacements. The registries were initiated by orthopedic societies and funded by the government or by levies on implant manufacturers. In some countries, data reporting and patient consent are required. Completeness is assessed by comparing data with the national health authority. All registries use implant survival as the primary outcome. Some registries use patient-reported outcomes as a secondary outcome. CONCLUSIONS: A registry offers many advantages; however, adequate long-term funding and completeness remain a challenge. It is unlikely that large-scale international registries can be implemented, but more countries should be encouraged to establish registries and, by adopting compatible processes, data could be pooled between national registries, adding considerably to their power and usefulness.

The effect of capsular repair, bone block healing, and position on the results of the Bristow-Latarjet procedure (study III): long-term follow-up in 319 shoulders.

BACKGROUND: We evaluated the results of the May modification of the Bristow-Latarjet procedure ("coracoid in standing position") in 319 shoulders with respect to (1) coracoid healing and position and (2) surgical treatment of the joint capsule. METHODS: From 1980 until 2004, all shoulders with a Bristow-Latarjet repair were registered at our hospital. This study consists of 3 different cohorts with respect to follow-up. Series 1, 118 shoulders operated on during 1980 through 1985, had 15 years' radiographic and clinical follow-up. Series 2, 167 shoulders that had surgery during 1986 through 1999, underwent retrospective follow-up by a questionnaire and scores--Western Ontario Shoulder Instability Index; Disabilities of the Arm, Shoulder and Hand; and Subjective Shoulder Value--after 10 to 23 years. Series 3, 34 shoulders treated during 2000 through 2004, with an added modified Bankart repair ("capsulopexy") in 33 shoulders, were prospectively followed up for 5 to 8 years with the same questionnaire and scores as series 2. RESULTS: Of 319 shoulders, 16 (5%) had 1 or more redislocations and 3 of these (1%) had revision surgery because of remaining instability. One or more subluxations were reported in 41 shoulders (13%). The worst scores were found in 16 shoulders with 2 or more subluxations (P < .001). Radiographs showed bony healing in 246 of 297 shoulders (83%), fibrous union in 34 (13%), migration by 0.5 cm or more in 14 (5%), and no visualization in 3 (1%). Five of six shoulders that had the transplant positioned 1 cm or more medial to the glenoid rim had redislocations (83%, P = .001). Shoulders with migrated transplants did not differ from those with bony or fibrous healing with respect to redislocations and subluxations. When just a horizontal capsular shift was added to the transfer, the recurrence rate (redislocations or subluxations) decreased, with 2 of 53 (4%)compared with 37 of 208 (18%) with just anatomic closure of the capsule (P = .005), and the Western Ontario Shoulder Instability Index score improved (92 vs 85.6, P = .048). In total, for 307 of 319 shoulders (96%), patients were satisfied or very satisfied at final follow-up. CONCLUSION: The open Bristow-Latarjet procedure yields good and consistent results, with bony fusion of the coracoid in 83%. A position of the coracoid 1 cm or more medial to the rim meant significantly more recurrences. The rate of recurrences decreased and subjective results improved when a horizontal capsular shift was added to the coracoid transfer.

Bristow-Latarjet and Bankart: a comparative study of shoulder stabilization in 185 shoulders during a seventeen-year follow-up.

BACKGROUND: In 2 Swedish hospitals, 88 consecutive shoulders underwent Bankart repair (B), and 97 consecutive shoulders underwent Bristow-Latarjet repair (B-L) for traumatic anterior recurrent instability. MATERIALS AND METHODS: Mean age at surgery was 28 years (B-L group) and 27 years (B group). All shoulders had a follow-up by letter or telephone after a mean of 17 years (range, 13-22 years). The patients answered a questionnaire and completed the Western Ontario Shoulder Index (WOSI), Disability of Arm Shoulder and Hand (DASH), and SSV (Simple Shoulder Value) assessments. RESULTS: Recurrance resulted revision surgery in 1 shoulder in the B-L group and in 5 shoulders in the B group (P = .08). Redislocation or subluxation after the index operation occurred in 13 of 97 B-L shoulders and in 25 of 87 of B shoulders (after excluding 1 patient with arthroplasty because of arthropathy, P = .017). Of the 96 Bristow shoulders, 94 patients were very satisfied/satisfied compared with 71 of 80 in the B series (P = .01). Mean WOSI score was 88 for B-L shoulders and 79 for B shoulders (P = .002). B-L shoulders also scored better on the DASH (P = .002) and SSV (P = .007). Patients had 11° loss of subjectively measured outward rotation with the arm at the side after B-L repair compared with 19° after Bankart (P = .012). The original Bankart, with tunnels through the glenoid rim, had less redislocation(s) or subluxation(s) than shoulders done with anchors (P = .048). CONCLUSIONS: Results were better after the Bristow-Latarjet repair than after Bankart repairs done with anchors with respect to postoperative stability and subjective evaluation. Shoulders with original Bankart repair also seemed to be more stable than shoulders repaired with anchors.

Loss of external rotation after open Bankart repair: an important prognostic factor for patient satisfaction.

The repair of the capsuloligamentous complex during shoulder stabilisation procedures can be followed by a persistent restricted capacity of external rotation. The prognostic importance of this loss in external rotation for patient satisfaction has not previously been evaluated. We therefore followed 68 consecutive patients operated for recurrent traumatic unidirectional anterior instability of the glenohumeral joint to assess the association between loss of external rotation and patient satisfaction. All patients underwent open Bankart repair. Two independent observers carried out a follow-up (5 years on average) after surgery. At follow-up, recurrent dislocation had developed in four of the 68 patients (6%). The median pre-operative Rowe score was 65 (range 42-87), which can be compared with 92 (range 46-100) at the follow-up. Three patients rated their outcome as poor, 13 as fair, 23 as good and 29 as excellent. There was a five-fold increased risk for a poor or fair outcome among patients with loss of external rotation in 0 degrees of abduction (age- and gender-adjusted odds ratio [OR] 5.3; 95% confidence interval [CI] 1.3-22.0, P = 0.0007). A linear association between the degree of loss in external rotation and patient dissatisfaction was found. The risk of being dissatisfied, independent of recurrent dislocation, occasional pain, positive apprehension test, age and gender, more than doubled (OR 2.6; 95% CI 1.4-4.8, P = 0.002) for every 10 degrees of post-operative loss of external rotation. Loss of external rotation almost explained all of the variation in patient satisfaction with a population attributable risk of 0.85 (95% CI 0.20-0.94). We conclude that open Bankart repair with a modified Rowe procedure is an excellent surgical option regarding stability, but restriction in external rotation reduces the likelihood of a satisfied patient.

Stability of cemented in-line pegged glenoid compared with keeled glenoid components in total shoulder arthroplasty.

BACKGROUND: Considerable interest has been focused on the design of the glenoid component used in total shoulder arthroplasty in order to reduce the risk of loosening. One design-related feature that has attracted attention is whether to use pegged or keeled cemented glenoid components. The main purpose of this study was to compare the fixation of cemented keeled glenoid components with that of cemented in-line pegged glenoid components. METHODS: In a prospective randomized study, we compared the stability of cemented, all-polyethylene, keeled glenoid components and cemented, all-polyethylene, in-line three-pegged glenoid components by radiostereometric analysis. Twenty-seven shoulders in twenty-five patients with osteoarthritis (twenty-two shoulders had primary and five shoulders had secondary osteoarthritis) were included. There were sixteen women and nine men, and the mean age was sixty-four years. Radiostereometric analysis and conventional radiographs were carried out at five days, at four months, and at one and two years postoperatively. RESULTS: The mean Constant and Murley score preoperatively and two years postoperatively was 25 and 70, respectively, for shoulders with the keeled glenoid component and 22 and 70 for the shoulders with a pegged component. No significant difference was detected between groups with regard to the average micromigration of the glenoid components at any of the time points. The average translation was <1 mm, while the median value was <0.3 mm at two years, with no significant difference between the different axes. In five shoulders (three with the keeled component and two with the pegged component), translation at two years was >1 mm. In fourteen shoulders (eight with the keeled and six with the pegged component), the rotation around one or several axes was >2 degrees . We were not able to detect any specific pattern with regard to movement for either type of component nor were we able to detect any difference between the two types of components in the way they migrated, if migration occurred. CONCLUSIONS: Cemented all-polyethylene keeled or in-line three-pegged glenoid components appear to have similar stability during the first two years after surgery. Studies with a longer follow-up period are needed to relate these findings to long-term clinical and radiographic outcomes.

Type I collagen alpha1 Sp1 polymorphism and the risk of cruciate ligament ruptures or shoulder dislocations.

BACKGROUND: Cruciate ligament ruptures and shoulder dislocations are often caused by trauma, but predisposing intrinsic factors might also influence the risk. These injuries are more common in those with a previously injured sibling, an observation that might indicate a genetic predisposition. It is well known that polymorphisms in the collagen I gene are associated not only with osteoporosis and osteoporotic fracture risk, but also with osteoarthritis. HYPOTHESIS: Because collagen I is abundant in ligaments and tendons, the authors hypothesized that collagen I alpha1 Sp1 polymorphism also was related to the occurrence of cruciate ligament ruptures and shoulder dislocations. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: A total of 358 patients and 325 randomly selected population-based female controls were included in the study. Of the cases, 233 had a cruciate ligament rupture and 126 had had a shoulder dislocation. Age-adjusted odds ratios (ORs) with 95% confidence intervals (CIs) estimated by unconditional logistic regression were used as measures of association. RESULTS: Compared with the homozygous SS category, the heterozygous participants displayed a similar risk (OR, 1.06; 95% CI, 0.76-1.49), whereas the ss genotype was underrepresented in the injured population compared with the controls (OR, 0.15; 95% CI, 0.03-0.68). This latter estimate was similar for both cruciate ligament ruptures and shoulder dislocations, and was furthermore not modified by general joint laxity. CONCLUSION: The authors found a substantially decreased risk of these injuries associated with collagen type I alpha1 Sp1 polymorphism. The study might encourage other investigators to consider further research in the area of genes and soft tissue injuries.

Cement and press-fit humeral stem fixation provides similar results in rheumatoid patients.

UNLABELLED: It is unclear whether humeral stems should be fixed with or without cement. We question whether press-fit fixation would provide similar results to cemented stem fixation. We prospectively randomized 26 shoulders in 24 patients with rheumatoid arthritis (20 women, 4 men) to have either a cemented or press-fit stem. In the press-fit group, stems were matched to the medullary canal, while lavage, pressurizing and distal plugging were used in the cemented group. We followed patients with conventional radiographs and radiostereometric analysis (RSA) at 5 to 7 days, 4 months, 1 year, and 2 years after surgery. One patient died from unrelated causes before the 1-year followup, while the remaining patients were followed according to the protocol. All but two patients were very satisfied or satisfied at 2 years. No stem was radiographically loose. There was no difference in micromotion between groups. The average rotation for all axes was less than 0.25 degrees for both groups and the average translation was less than 0.32 mm for all three axes including subsidence, which was less than 0.1 mm for the uncemented stems. We concluded at 2 years these stems provided similar fixation in rheumatoid shoulders. LEVEL OF EVIDENCE: Therapeutic Level I. See the Guidelines for Authors for a complete description of levels of evidence.

Long-standing increased bone turnover at the fixation points after anterior cruciate ligament reconstruction: a positron emission tomography (PET) study of 8 patients.

BACKGROUND: A secure incorporation of the graft in a bone tunnel is a prerequisite for successful anterior cruciate ligament reconstruction. In this cross-sectional pilot study, we studied the healing process with positron emission tomography (PET) scanning. PATIENTS AND METHODS: 8 young patients underwent an anterior cruciate ligament reconstruction with a bonepatellar tendon-bone graft (BTB, n = 4) or a quadruple semitendinosus and gracilis graft (ST/G, n = 4). Regional bone turnover was quantified with an 18F-fluoride PET scan in each patient 1 day, 3 weeks, 7 months, or 22 months after surgery. RESULTS: The highest activity level was found 3 weeks after surgery, but the activity at the femoral fixation points was markedly increased even after 7 months. The bone turnover was almost normalized 22 months after the operation. INTERPRETATION: It would take at least 7 months until an anterior cruciate ligament graft, fixed with an interference screw, is completely incorporated. This finding is important for postoperative rehabilitation. Furthermore, PET is a feasible tool when studying new ways of fixing soft tissue to bone.

Improved healing of ligament to bone with point fixation in rabbits.

BACKGROUND: Secure healing of soft tissue to bone is a prerequisite for many orthopedic operations. This healing can be achieved either by pressing the tissue against the bone (press fixation) or by suturing the soft tissue to the bone (point fixation). EXPERIMENTS AND FINDINGS: We tested the hypothesis that point fixation of soft tissue to bone results in better mechanical properties than press fixation. 10 skeletally mature New Zealand White rabbits were operated on bilaterally at the knees. The medial collateral ligaments were fixated to the bone just above the original insertion on the tibia. Two types of plates were used for this purpose, one with flat undersurface (left knee) and the other one with a pegged undersurface (right knee). The pegged plate was thought to mimic fixation achieved with suture anchors. After 4 weeks, mechanical testing revealed an almost doubled force at failure, stiffness and energy uptake in the knees operated with the pegged plates. INTERPRETATION: Suture anchors or devices with a pegged undersurface are better for soft tissue fixation to bone than devices with a flat surface, such as screws with washers or staples.

Stable fixation of the ulnar component in the Kudo elbow prosthesis. A radiostereometric (RSA) study of 13 prostheses with 2-year follow-up.

BACKGROUND: Concern has been expressed about the large number of radiolucent lines around the ulnar component of the Kudo elbow prosthesis in medium-term follow-up. PATIENTS AND METHODS: We studied the metal-backed cemented ulnar component in 13 Kudo elbow prostheses (type 5) using radiostereometric analysis (RSA). All patients had rheumatoid arthritis. There were 2 men and 9 women with a mean age of 55 years. 2 were operated bilaterally. The metal-backed ulnar component was marked with three 0.8 mm tantalum spheres and the proximal ulna with 5 spheres of 0.8 or 1.0 mm diameter. The initial RSA examination was performed during the first week after the operation. Further examinations were done at 4, 12 and 24 months. Conventional radiographs were taken during the first week postoperatively, and at 12 and 24 months. RESULTS: Translations (medial/lateral, antero/posterior and proximal/distal) were less than 0.5 mm in all but 1 patient who had a maximal translation of 3.4 mm distally. The mean rotations around all three axes were less than 0.4 degrees. The patient who had a translation of 3.4 mm also had varus angulation exceeding 4 degrees. This patient also had progressive circumferential radiolucent lines on conventional radiographs. The Mayo elbow score increased from 40 (25-65) before surgery to 92 (45-100) at 2 years. INTERPRETATION: The fixation of the metal-backed ulnar component of the Kudo elbow prosthesis at 2 years is good.

Tourniquet-induced ischemia and reperfusion in human skeletal muscle.

Microdialysis conceivably enables longitudinal and simultaneous investigation of several metabolites by repeated measurements in skeletal muscle. We used and evaluated microdialysis as an in vivo method to characterize the time-course and relative kinetics of pyruvate, glucose, lactate, glycerol, hypoxanthine, uric acid, and urea, in skeletal muscles, exposed to ischemia and reperfusion, in eight patients having arthroscopic-assisted anterior cruciate ligament reconstruction. A dialysis probe was implanted before surgery in the rectus femoris muscle. Dialysate samples were collected at 10-minute intervals at a flow rate of 1 microL/minute until 2 hours after tourniquet deflation. Ninety minutes of ischemia resulted in accumulation of lactate (234% +/- 38%), hypoxanthine (582% +/- 166%), and glycerol (146% +/- 46%), consumption of glucose (54% +/- 9%) and pyruvate (16% +/- 44%), and a slight decrease of urea (78% +/- 11%) compared with baseline (100%). Uric acid was unchanged (95% +/- 12%). Within 90 minutes after tourniquet deflation the concentrations were virtually normalized for all measured metabolites, suggesting that the duration of ischemia was well tolerated by the patients. The results indicate that the use of microdialysis for monitoring energy metabolic events during orthopaedic surgery that requires ischemia and reperfusion is feasible and safe.