Introduction

Malrotation following total knee replacement is directly related to poor outcome. The knowledge of proximal and distal rotational axes and angles of the femur is therefore of high importance. The aim of the study was to determine whether the most used proximal and distal femoral angles; femoral anteversion angle (FAA) and posterior condylar angle (PCA) were different within individuals, between right, left and gender. As well, we studied whether the “inferior condylar angle” is correlated to the PCA and therefore useful in determining the rotation of the distal femur.

Background

Many scoring systems exist that assess ankle function, none of them are validated for use in a group of higher demand patients. This group of patients there have potential problems with ceiling effects, not being able to detect change or that a sports-subscale is not included. This study was to create a validated self-administered scoring system for ankle injuries in athletes by studying existing scoring systems and key-informant interviews.

The need for a better understanding of factors that influence surgical outcome has grown as many complications are thought to be avoidable. One approach proven useful in studying surgical procedures is time-action analysis (TAA), a method which objectively determines the efficiency of individual steps. The aim of this study was to assess the surgical process of total knee arthroplasty using TAA, thus enhancing the insight into the procedure, influence of team members and adverse events, eventually leading to process improvement and reduction of error probability.

Methods: In two high output centres and one teaching hospital 37 TKA surgeries were recorded, using 3 different knee systems (NexGen, LCS and Triathlon). The process was analyzed using a fixed taxonomy and the duration, limitations and repetitions were determined using video analysis software. The efficiency of the surgeon was calculated by dividing the time the surgeon spends operating by the time operating plus the time spent talking, thinking or repeating.

Results: Although the two high output centres used different knee systems there was no difference in operating time (47min. (95%CI, 43.2 to 50.1) versus 47min. (42.1 to 51.9)). With an inexperienced nurse the waiting time increased in both hospitals during the femoral osteotomy phase (p= 0.01 and p=0.05). Comparing to a training hospital, the tibial alignment phase showed lower surgical efficiency for both the consultant and 6th year residents (80% vs. 95%, p=0.01). Also the nurse waiting time increased during all phases (18min. vs. 2min., p=0.00). In the teaching hospital more problems (communication, instrument and skill) occurred (mean 19 vs. 5 and 2, p=0.00) and twice as much communication problems existed with residents regardless of nurse experience. Surprisingly the number of problems handling instruments increased inversely with nurse experience (p=0.02) as did the waiting time (27min. vs. 15min.) again being highest in the femoral osteotomy phase (p=0.00).

Conclusion: The similar results in the high output centres show that TKA is a similar and structured process regardless of the knee system, its efficiency mainly dependent on surgical output. The decrease in resident efficiency is caused by less structured use of instruments and miscommunication with the nurse. For nurses the femoral osteotomy phase is most difficult, requiring high attention due to frequent changing of different pins and cutting blocks. Unfamiliarity with instruments (i.e. low volume) results in higher waiting times. Regardless of the knee system the steps of TKA are similar, therefore a consistent surgeon-nurse (OR tech) verbal interaction is advocated especially with a less experienced team. Training should focus knowledge of instruments using uniform names. Extra attention should be paid by those who do not often place knees to communication with the nurse and clear order of the procedure.

Introduction: There is still debate on the effect of operative treatment on severe displaced intra-articular fractures of the os calcis. Operatively treatment consists of open reduction or percutanious screw fixation, with conflicting results. Although the results of either operative treatment are published, little is known about the long term results of non-surgical treatment of these difficult fractures.

Patients and Methods: We analyzed the data of 35 patients with an intra-articular fracture of the oc calcis which were treated with a plaster cast between 1994 and 2006. All radiographs of the fracture and the radiograph at the latest follow-up were analyzed. All patients which could be traced were invited for a clinical examination and a radiograph. A Foot Function Index-score (FFI) and AOFAS score were recorded as clinical outcome. A regression analysis was performed with the clinical outcome (AOFAS score and FFI) as outcome and age, gender, Bohler’s and Gissane’s angles, trauma mechanism and type of fracture as predictors.

Results: After a median follow-up of 10 years the mean AOFAS score was 75.8 (range29–100) and the FFI was 22.9 (range 0–71). In the regression analysis we found that none of the predictors could predict the outcome. Even the Bohler’s and Gisae angle did not predict the clinical outcome. Although there was a strong correlation between the Bohler’s angle on the lateral radiograph and the occurrence of degenerative changes in the long term follow-up, both Bohler’s angle and the degenerative changes did not correlate with the clinical measures.

Conclusion: Although Bohler’s angle is a strong predictor for degenerative changes after a calcaneal fracture, both Bohler’s angle and the degenerative changes on the radiograph were not correlated with the clinical outcome.

Aim: Suction fit is a common phenomenon of metal on metal (MOM) or ceramic on ceramic hip joints, in which the head and the cup can be hold to each other in the presence of lubricant. The aim of this study was to measure the suction force of MOM hip joints with different clearances and fluid viscosities.

Materials and Methods: CoCrMo hip prostheses of Ø50 mm with two diametral clearances of 100 and 200 microns were tested. A range of fluids were made using different ratios of deionized water and carboxy-methyl cellulose (CMC). The fluid viscosities ranged from 0.0011 to 0.3 Pa s determined by a cone-on-plate viscometer (Physica Rheolab MC100). Before the measurement, about 1 ml fluid was placed in the cup and the bearing surfaces of both the head and the cup were fully wetted by rotating the femoral ball in the cup. A pre-loaded 3kN was applied to push the head into the cup by a servohydraulic test machine, the femoral head was then lifted out of the cup at a rate of 2 mm/s and the maximum suction force value was recorded.

Results: Generally, the suction force increased with the increase of viscosity for both 100 and 200 microns clearances. In the lower range of the viscosity, the suction force increased rapidly, but when the viscosity reached a certain value it leveled off to about 190 N for the 100 microns clearance and 150 N for the 200 microns clearance. In the whole range of viscosity, the suction forces of 100 microns clearance were higher than those of 200 microns clearance and the differences were statistically significant (t-test, P< 0.01). In the lower range of viscosity (< 0.04 Pa s), the suction force of 100 microns clearance was more than two times higher than that of 200 microns clearance.

Discussion: For a MOM hip joint, suction force can be explained by the vacuum within the bearings. When the clearance is small and the lubricant viscosity is high, the edge of the bearing surfaces can be easily sealed off so that certain degree of vacuum can be produced between the head and the cup. In this test, the maximum suction force for the Ø50 mm MOM hip joint can be calculated as: F = (projected area) x (atmospheric pressure) = 196 (N). The results confirmed that the suction force of Ø50 mm components can not be higher than 196 N.

Although suction force may have a benefit in reducing the risk of dislocation, it may prevent lubricant recovery between the bearings and will influence the sliding resistance. If the suction force is too high, the head and cup can be held together such that the recovery of synovial fluid is restricted or impossible, even when the hip is not loaded during the swing phase. Both the clearance and the viscosity have a significant effect to determine the suction force and the lubrication of MOM hip joints. It is concluded that suction force is a factor to be considered during the selection of MOM hip joint clearance.

Introduction : The reason why heterotopic ossification develops after total hip arthroplasty is still not known, but it is assumed that inflammatory reaction is the major driving force. In literature little is known about the cytokine levels at the site of surgery, most measurements are done in serum. This study was conducted to investigate if the levels of different pro- en anti-inflammatory cytokines are measurable in drainage fluid and, when measurable, whether we can find a difference in cytokine concentration between one and six hours postoperatively.

Materials and methods: Samples from the drainage system in 30 consecutive patients undergoing primairy total hip replacement were collected at one and six hours after closure of the wound. GM-CSF, G-CSF, IFN-γ, TNF, MCP-1, IL-1beta, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12, IL-13 and MIP-1beta levels were measured in the drainage fluids.

Results: Measurable levels of all cytokines studied were found, except for IL-17. A significant elevation of almost all cytokines was observed between the sample after one hour and six hours postoperatively. The elevation was significant for all cytokines except IL-10 and MIP-1b. We found a strong correlation between the different pro-inflammatory cytokines. Levels are much higher than previously shown levels in serum. When computing the IL-6 to IL-10 ratio, this ratio increased from 304 (SD 256) to 12357 (SD 6788) (p< 0,000), which shows an increased predominance of the pro-inflammatory interleukines when comparing the measurements after one and six hours respectively.

Conclusion: Detectable levels of numerous cytokines can be measured in drainage fluid post-operatively. The levels of most cytokines in drainage fluid are higher in samples taken six hours after surgery as compared to samples taken after one hour. Further studies are needed to detect the relation between these cytokine concentrations and the heterotopic bone formation.

Introduction: The Kudo total elbow prosthesis (TEP) is a well established implant, with good mid-term results. In the last decades this implant underwent several modifications. The last modification (type 5) has overcome the problems of stem breakage of the humeral component by modifications of the stem. The ulnar component can be placed with or without cement; the humeral component is always placed without cement.

Aims of this study: To examine the mid-term results of the Kudo type 5 TEP and to compare the results of the uncemented Kudo total elbow prosthesis (TEP), with the hybrid Kudo TEP (uncemented humeral component and cemented ulnar component).

Material and methods: Between 1994 and 2004 89 Kudo type 5 TEPs were placed for joint destruction due to rheumatoid arthritis (RA). The mean age of the patients was 55 years (range 21–84 years). Twenty-two prostheses were placed in males, 66 in females. Forty-nine TEPs (group 1) were fully uncemented and 40 TEPs (group 2) were hybrid (humeral component uncemented, ulnar component cemented). The groups were comparable as related to age, sex and indication for surgery. After implantation of the prosthesis a radiograph was made every two years or sooner when indicated.

Evaluation took place after an average of 5.3 years of follow up (range 1.7–10.6 years) and consisted of a questionnaire, elbow function assessment and anteroposterior and lateral radiographs in a standard way. Pre- and postoperative range of motion was analysed with the paired T-test. Pain scores and EFAS scores postoperatively were analysed using the independent sample T-test. The survival of the prosthesis was calculated from the time of implant to the time of revision or occurrence of radiolucencies.

Results: In group 1, seven ulnar components had to be revised due to aseptic loosening after a mean follow-up of 4 years (range 1.5–6.3 years). Three of these ulnar components were short-stemmed, four were long stemmed uncemented.

In group 2 five patients died of an unrelated course and no revisions have taken place, one TEP is loose on X-ray (after two years) with a suspicion of septic loosening The EFAS scores (87 in group 1 and 91 in group 2) and range of motion (84 degrees in group 1 and 90 degrees in group 2) were the same in both groups.

Conclusion: In this group of patients with RA the survival of the Kudo type 5 TEP with cemented ulnar component is better as compared to the uncemented ulnar component.

Introduction: Total ankle prostheses (TAP’s) are implanted for end stage cartilage damage especially in patients with rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA) or post-traumatic arthritis. Little is known about the long term survival of these prostheses in patients with RA and JIA. In this study we examined the outcome of TAP in these patients.

Patients and methods: Between 1994 and 2004 85 TAP’s were implanted in 58 cases (10 males and 48 females) with RA (n=53) or juvenile chronic arthritis (n=5). The records of all patients were reviewed. Every patient was invited for a visit to our outpatient clinic for a history taking, a physical examination and a Kofoed ankle score (a clinical score for ankle function ranging from 0 to 100) was obtained.

Results: The record of every patient was available for review. Two patients had died (cause of death was unrelated to the surgery), and 56 patients could be reexamined. A perioperative fracture (8 medial 3 lateral and 2 tibial) occurred in 13 cases. The fractures were fixed in the same operation and healed without complications; none of these prostheses needed a reintervention. After a mean follow up of 2.7 years (range 1 to 9 years) two patients died with the prosthesis in situ, one patient underwent an above knee amputation for infected arthroplasties of ankle and knee and four prostheses were removed because of loosening or malfunctioning of the prosthesis and arthrodeses were performed. The other 51 cases were analysed and showed a mean Kofoed ankle score of 72.8 (SD=15.8). This score is similar to scores obtained from patients receiving ankle arthroplasties for non-rheumatic indications.

Conclusions: Placement of total ankle prostheses in patients with RA shows good medium term results. The intra-operative fracture rate is high, but does not affect the outcome; none of the failed arthroplasties was due to a preoperative fracture.

Introduction: The standard procedure when operating the rheumatoid forefoot is resection arthroplasty of the metatarsophalangeal joints of the lesser rays. Correction of the hallux is mostly achieved by arthrodesis of the first metatarsophalangeal joint. Good clinical results (with a follow-up of over ten years) have been reported when a combination of these two techniques is used. Another technique is repositioning of the metatarsophalangeal subluxation or dislocation of the lesser rays, thereby preserving the metatarsophalangeal joints, thus leaving the function of the aponeurosis plantaris intact. As a result of this it can be expected that unrolling of the forefoot is unaffected and therefore a better function of the forefoot remains.

Aim: To assess the results of forefoot reconstruction using the repositioning technique performed in 54 feet (39 patients) by one surgeon using this technique.

Methods: Fifty-four feet (39 RA patients) were treated with the technique of repositioning the metatarsophalangeal subluxation or dislocation. All surgery was performed by one orthopaedic surgeon. In case of severe deformity of the metatarsophalangeal joint of the hallux, an arthrodesis was performed. All patients were reviewed after a mean follow up of 40 months (range 12–72 months) and an AOFAS [American Orthopaedic Foot and Ankle Society] foot score, and FFI [Foot Function Index] were obtained.

Results: At a mean of 40 months (SD=15.6 months) postoperatively, the mean AOFAS forefoot score was 69.80 (SD=11.8) if, in addition of repositioning the metatarsophalangeal joints, an arthrodesis of the hallux was performed. In patients with no operation on the hallux, the AOFAS score was 42.2 (SD=18.8) (P=0,001). The postoperative FFI-scores were 74.0 (SD=17.5) and 57.6 (SD=14.6) respectively (P=0,026)

Conclusions: Reconstruction of the rheumatoid forefoot by repositioning the metatarsophalangeal joints of the lesser rays, thereby preserving the joints, can be considered a procedure that provides improvement in the clinical outcome. Best results were seen in patients in whom, in addition of reconstruction of the lesser rays, an arthrodesis of the hallux was performed.