Validation of a Three-Dimensional Weight-Bearing Measurement Protocol for Medial Open-Wedge High Tibial Osteotomy

Three-dimensional (3D) deformity assessment and leg realignment planning is emerging. The aim of this study was to (1) validate a novel 3D planning modality that incorporates the weight-bearing (WB) state (3D WB) by comparing it to existing modalities (3D non-weight-bearing (NWB), 2D WB) and (2) evaluate the influence of the modality (2D vs. 3D) and the WB condition on the measurements. Three different planning and deformity measurement protocols were analyzed in 19 legs that underwent medial open-wedge high tibial osteotomy (HTO): (1) a 3D WB protocol, after 2D/3D registration of 3D CT models onto the long-leg radiograph (LLR) (3D WB), (2) a 3D NWB protocol based on the 3D surface models obtained in the supine position (3D NWB), and (3) a 2D WB protocol based on the LLR (2D WB). The hip-knee-ankle angle (HKA), joint line convergence angle (JLCA), and the achieved surgical correction were measured for each modality and patient. All the measurement protocols demonstrated excellent intermodal agreement for the achieved surgical correction, with an ICC of 0.90 (95% CI: 0.76-0.96)) (p < 0.001). Surgical correction had a higher mean absolute difference compared to the 3D opening angle (OA) when measured with the WB protocols (3D WB: 2.7 ± 1.8°, 3D NWB: 1.9 ± 1.3°, 2D WB: 2.2 ± 1.3°), but it did not show statistical significance. The novel planning modality (3D WB) demonstrated excellent agreement when measuring the surgical correction after HTO compared to existing modalities.

Functional and Radiologic Outcomes of Degenerative Versus Traumatic Full-Thickness Rotator Cuff Tears Involving the Supraspinatus Tendon

BACKGROUND

Arthroscopic rotator cuff repair (ARCR) is among the most commonly performed orthopaedic procedures. Several factors-including age, sex, and tear severity-have been identified as predictors for outcome after repair. The influence of the tear etiology on functional and structural outcome remains controversial.

PURPOSE

To investigate the influence of tear etiology (degenerative vs traumatic) on functional and structural outcomes in patients with supraspinatus tendon tears.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Patients undergoing ARCR from 19 centers were prospectively enrolled between June 2020 and November 2021. Full-thickness, nonmassive tears involving the supraspinatus tendon were included. Tears were classified as degenerative (chronic shoulder pain, no history of trauma) or traumatic (acute, traumatic onset, no previous shoulder pain). Range of motion, strength, the Subjective Shoulder Value, the Oxford Shoulder Score (OSS), and the Constant-Murley Score (CMS) were assessed before (baseline) and 6 and 12 months after ARCR. The Subjective Shoulder Value and the OSS were also determined at the 24-month follow-up. Repair integrity after 12 months was documented, as well as additional surgeries up to the 24-month follow-up. Tear groups were compared using mixed models adjusted for potential confounding effects.

RESULTS

From a cohort of 973 consecutive patients, 421 patients (degenerative tear, n = 230; traumatic tear, n = 191) met the inclusion criteria. The traumatic tear group had lower mean baseline OSS and CMS scores but significantly greater score changes 12 months after ARCR (OSS, 18 [SD, 8]; CMS, 34 [SD,18] vs degenerative: OSS, 15 [SD, 8]; CMS, 22 [SD, 15]) (P < .001) and significantly higher 12-month overall scores (OSS, 44 [SD, 5]; CMS, 79 [SD, 9] vs degenerative: OSS, 42 [SD, 7]; CMS, 76 [SD, 12]) (P≤ .006). At the 24-month follow-up, neither the OSS (degenerative, 44 [SD, 6]; traumatic, 45 [SD, 6]; P = .346) nor the rates of repair failure (degenerative, 14 [6.1%]; traumatic 12 [6.3%]; P = .934) and additional surgeries (7 [3%]; 7 [3.7%]; P = .723) differed between groups.

CONCLUSION

Patients with degenerative and traumatic full-thickness supraspinatus tendon tears who had ARCR show satisfactory short-term functional results. Although patients with traumatic tears have lower baseline functional scores, they rehabilitate over time and show comparable clinical results 1 year after ARCR. Similarly, degenerative and traumatic rotator cuff tears show comparable structural outcomes, which suggests that degenerated tendons retain healing potential.

The Unloading Effect of Supramalleolar Versus Sliding Calcaneal Osteotomy for Treatment of Osteochondral Lesions of the Medial Talus: A Biomechanical Study

Background

In patients with osteochondral lesion, defects of the medial talus, or failed cartilage surgery, a periarticular osteotomy can unload the medial compartment.

Purpose

To compare the effects of supramalleolar osteotomy (SMOT) versus sliding calcaneal osteotomy (SCO) for pressure redistribution and unloading of the medial ankle joint in normal, varus-aligned, and valgus-aligned distal tibiae.

Study Design

Controlled laboratory study.

Methods

Included were 8 cadaveric lower legs with verified neutral ankle alignment (lateral distal tibial angle [LDTA] = 0°) and hindfoot valgus within normal range (0°-10°). SMOT was performed to modify LDTA between 5° valgus, neutral, and 5° varus. In addition, a 10-mm lateral SCO was performed and tested in each position in random order. Axial loading (700 N) of the tibia was applied with the foot in neutral alignment in a customized testing frame. Pressure distribution in the ankle joint and subtalar joint, center of force, and contact area were recorded using high-resolution Tekscan pressure sensors.

Results

At neutral tibial alignment, SCO unloaded the medial joint by a mean of 10% ± 10% or 66 ± 51 N (P = .04) compared with 6% ± 12% or 55 ± 72 N with SMOT to 5° valgus (P = .12). The achieved deload was not significantly different (ns) between techniques. In ankles with 5° varus alignment at baseline, SMOT to correct LDTA to neutral insufficiently addressed pressure redistribution and increased medial load by 6% ± 9% or 34 ± 33 N (ns). LDTA correction to 5° valgus (10° SMOT) unloaded the medial joint by 0.4% ± 14% or 20 ± 75 N (ns) compared with 9% ± 11% or 36 ± 45 N with SCO (ns). SCO was significantly superior to 5° SMOT (P = .017) but not 10° SMOT. The subtalar joint was affected by both SCO and SMOT, where SCO unloaded but SMOT loaded the medial side.

Conclusion

SCO reliably unloaded the medial compartment of the ankle joint for a neutral tibial axis. Changes in the LDTA by SMOT did not positively affect load distribution, especially in varus alignment. The subtalar joint was affected by SCO and SMOT in opposite ways, which should be considered in the treatment algorithm.

Clinical Relevance

SCO may be considered a reliable option for beneficial load-shifting in ankles with neutral alignment or 5° varus malalignment.

Total hip arthroplasty through the direct anterior approach for sequelae of Legg-Calvé-Perthes disease

INTRODUCTION

Due to multiplanar deformities of the hip, total hip arthroplasty (THA) for sequelae of Legg-Calvé-Perthes disease (LCPD) is often technically demanding. This study aimed to compare the clinical and radiographic outcomes of patients with sequelae of LCPD undergoing THA through the direct anterior approach (DAA) and non-anterior approaches to the hip.

METHODS

All patients with sequelae of LCPD who underwent primary THA between 2004 and 2018 (minimum follow-up: 2 years) were evaluated and separated into two groups: THA through the DAA (Group AA), or THA through non-anterior approaches to the hip (Group non-AA). Furthermore, a consecutive control group of patients undergoing unilateral THA through the DAA for primary hip osteoarthritis (Group CC) was retrospectively reviewed for comparison.

RESULTS

Group AA comprises 14 hips, group non-AA 17 hips and group CC 30 hips. Mean follow-up was 8.6 (± 5.2; 2-15), 9.0 (± 4.6; 3-17) and 8.1 (± 2.2; 5-12) years, respectively. At latest follow-up, Harris Hip Score was 90 (± 20; 26-100), 84 (± 15; 57-100), and 95 (± 9; 63-100) points, respectively. Overall, 6 patients treated for LCPD (each 3 patient in the AA and non-AA group) developed postoperative sciatic nerve palsy, of which only one was permanent. Complication-related revision rate at the latest follow-up was 15% in the AA-group and 25% in the non-AA group, respectively.

CONCLUSION

THA through the DAA might be a credible option for the treatment of sequelae of LCPD with comparable complication rates and functional outcomes to non-anterior approaches.

Registration based assessment of femoral torsion for rotational osteotomies based on the contralateral anatomy

Background

Computer-assisted techniques for surgical treatment of femoral deformities have become increasingly important. In state-of-the-art 3D deformity assessments, the contralateral side is used as template for correction as it commonly represents normal anatomy. Contributing to this, an iterative closest point (ICP) algorithm is used for registration. However, the anatomical sections of the femur with idiosyncratic features, which allow for a consistent deformity assessment with ICP algorithms being unknown. Furthermore, if there is a side-to-side difference, this is not considered in error quantification.

The aim of this study was to analyze the influence and value of the different sections of the femur in 3D assessment of femoral deformities based on the contralateral anatomy.

Material and methods

3D triangular surface models were created from CT of 100 paired femurs (50 cadavers) without pathological anatomy. The femurs were divided into sections of eponymous anatomy of a predefined percentage of the whole femoral length. A surface registration algorithm was applied to superimpose the ipsilateral on the contralateral side. We evaluated 3D femoral contralateral registration (FCR) errors, defined as difference in 3D rotation of the respective femoral section before and after registration to the contralateral side. To compare this method, we quantified the landmark-based femoral torsion (LB FT). This was defined as the intra-individual difference in overall femoral torsion using with a landmark-based method.

Results

Contralateral rotational deviation ranged from 0° to 9.3° of the assessed femoral sections, depending on the section. Among the sections, the FCR error using the proximal diaphyseal area for registration was larger than any other sectional error. A combination of the lesser trochanter and the proximal diaphyseal area showed the smallest error. The LB FT error was significantly larger than any sectional error (p < 0.001).

Conclusion

We demonstrated that if the contralateral femur is used as reconstruction template, the built-in errors with the registration-based approach are smaller than the intraindividual difference of the femoral torsion between both sides. The errors are depending on the section and their idiosyncratic features used for registration. For rotational osteotomies a combination of the lesser trochanter and the proximal diaphyseal area sections seems to allow for a reconstruction with a minimal error.

The effect of native knee rotation on the tibial-tubercle-trochlear-groove distance in patients with patellar instability: an analysis of MRI and CT measurements

BACKGROUND

This study aimed to quantify the effect of lower limb rotational parameters on the difference in the tibial-tubercle-trochlear-groove (TTTG) distance when assessed with magnetic resonance imaging (MRI) and computed tomography (CT) in patients with patellar instability. It was hypothesized that an increased native knee rotation angle significantly contributes to an underestimation of TTTG by MRI.

METHODS

Forty patients with patellar instability who had undergone standard radiographs, MRI and CT scans were included in this retrospective study. A musculoskeletal radiologist assessed all imaging for TTTG, femoral and tibial rotation, knee rotation and flexion angle, and trochlear dysplasia. ΔTTTG was defined as the TTTG measured on MRI subtracted from the TTTG measured on CT. Statistical analysis determined the effect of these parameters on the calculated difference between TTTG when measured on CT and MRI.

RESULTS

Equal knee flexion in MRI and CT resulted in a ΔTTTG of 0.1 ± 0.3 mm compared to 4.0 ± 3.3 mm in patients with different knee flexion angles in both imaging acquisitions (p = 0.036). The knee rotation angle measured on CT (native knee rotation angle) was negatively correlated with ΔTTTG (r = - 0.365; p = 0.002), while neither tibial nor femoral rotation showed any associations with TTTG (n.s.). Trochlear dysplasia did not show any significant correlation with ΔTTTG, regardless of classification by Dejour or Lippacher (n.s.). Both the native knee rotation angle and the MRI knee flexion angle were independent predictors of ΔTTTG, yet with an opposing effect (knee rotation: 95% Confidence Interval [CI] for β - 0.468 to - 0.154, p < 0.001; knee flexion 95% CI for β 0.292 to 0.587, p < 0.001). Patients with a native knee rotation angle > 20° showed a ΔTTTG of - 5.8 ± 4.0 mm (MRI rather overestimates TTTG) compared to 0.9 ± 4.1 mm Δ TTTG (MRI rather underestimates TTTG) in patients with < 20° native knee rotation angle.

CONCLUSION

The native knee rotation angle is an independent, inversely correlated predictor of ΔTTTG, thus opposing the effect of knee flexion during MRI acquisition. Consequently, these results suggest that not only knee flexion but also knee rotation should be appreciated when assessing TTTG during patellar instability diagnostic evaluation as it can potentially lead to a false estimation of the TTTG distance on MRI.

LEVEL OF EVIDENCE

Level III.

Elongation Patterns of the Superficial Medial Collateral Ligament and the Posterior Oblique Ligament: A 3-Dimensional, Weightbearing Computed Tomography Simulation

Background:

Although length change patterns of the medial knee structures have been reported, either the weightbearing state was not considered or quantitative radiographic landmarks that allow the identification of the insertion sites were not reported.

Purpose:

To (1) analyze the length changes of the superficial medial collateral ligament (sMCL) and posterior oblique ligament (POL) under weightbearing conditions and (2) to identify the femoral sMCL insertion site that demonstrates the smallest length changes during knee flexion and report quantitative radiographic landmarks.

Study Design:

Descriptive laboratory study.

Methods:

The authors performed a 3-dimensional (3D) analysis of 10 healthy knees from 0° to 120° of knee flexion using weightbearing computed tomography (CT) scans. Ligament length changes of the sMCL and POL during knee flexion were analyzed using an automatic string generation algorithm. The most isometric femoral insertion of the sMCL that demonstrated the smallest length changes throughout the full range of motion (ROM) was identified. Radiographic landmarks were reported on an isometric grid defined by a true lateral view of the 3D CT model and transferred to a digitally reconstructed radiograph.

Results:

The sMCL demonstrated small ligament length changes, and the POL demonstrated substantial shortening during knee flexion ( P = .005). Shortening of the POL started from 30° of flexion. The most isometric femoral sMCL insertion was located 0.6 ± 1.7 mm posterior and 0.8 ± 1.2 mm inferior to the center of the sMCL insertion and prevented ligament length changes >5% during knee flexion in all participants. The insertion was located 47.8% ± 2.7% from the anterior femoral cortex and 46.3% ± 1.9% from the joint line on a true lateral 3D CT view.

Conclusion:

The POL demonstrated substantial shortening starting from 30° of knee flexion and requires tightening near full extension to avoid overconstraint. Femoral sMCL graft placement directly posteroinferior to the center of the anatomical insertion of the sMCL demonstrated the most isometric behavior during knee flexion.

Clinical Relevance:

The described elongation patterns of the sMCL and POL aid in guiding surgical medial knee reconstruction and preventing graft lengthening and overconstraint of the medial compartment. Repetitive graft lengthening is associated with graft failure, and overconstraint leads to increased compartment pressure, cartilage degeneration, and restricted ROM.

Elongation Patterns of Posterolateral Corner Reconstruction Techniques: Results Using 3-Dimensional Weightbearing Computed Tomography Simulation

Background:

The isometric characteristics of nonanatomic and anatomic posterolateral corner (PLC) reconstruction techniques under weightbearing conditions remain unclear.

Purpose:

To (1) simulate graft elongation patterns during knee flexion for 3 different PLC reconstruction techniques (Larson, Arciero, and LaPrade) and (2) compute the most isometric insertion points of the fibular collateral ligament (FCL) graft strands for each technique and report quantitative radiographic landmarks.

Study Design:

Descriptive laboratory study.

Methods:

The authors performed a 3-dimensional simulation of 10 healthy knees from 0° to 120° of flexion using weightbearing computed tomography (CT) scans. The simulation was used to calculate ligament length changes during knee flexion for the PLC reconstruction techniques of Larson (nonanatomic single-bundle fibular sling reconstruction), Arciero (anatomic reconstruction with additional popliteofibular ligament graft strand), and LaPrade (anatomic reconstruction with popliteofibular ligament graft strand and popliteus tendon graft strand). The most isometric femoral insertion points for the FCL graft strands were computed within a 10-mm radius around the lateral epicondyle (LE), using an automatic string generation algorithm (0 indicating perfect isometry). Radiographic landmarks for the most isometric points were reported.

Results:

Median graft lengthening during knee flexion was similar for the anterior graft strands of all 3 techniques. The posterior graft strands demonstrated significant differences, from lengthening for the Arciero (9.9 mm [range, 6.7 to 15.9 mm]) and LaPrade (10.2 mm [range, 4.1 to 19.7 mm]) techniques to shortening for the Larson technique (−17.1 mm [range, −9.3 to −22.3 mm]; P < .0010). The most isometric point for the FCL graft strands of all techniques was located at a median of 2.2 mm (range, −2.2 to 4.5 mm) posterior and 0.3 mm (range, −1.8 to 3.7 mm) distal to the LE.

Conclusion:

Overconstraint can be avoided by tensioning the posterior graft strands in the Larson technique in extension, and in the Arciero and LaPrade techniques at a minimum of 60° of knee flexion. The most isometric point was located posterodistal to the LE.

Clinical Relevance:

The described isometric behavior of nonanatomic and anatomic PLC reconstruction techniques can guide optimal surgical reconstruction and prevent graft lengthening and overconstraint of the lateral compartment in knee flexion. Repetitive graft lengthening has been found to be associated with graft failure, and overconstraint favors lateral compartment pressure and cartilage degeneration.

Talus morphology differs between flatfeet and controls, but its variety has no influence on extent of surgical deformity correction

BACKGROUND

Progressive collapsing foot deformity (PCFD) is a complex 3-dimensional (3-D) deformity with varying degrees of hindfoot valgus, forefoot abduction, and midfoot varus. The first aim of this study was to perform a 3-D analysis of the talus morphology between symptomatic PCFD patients that underwent operative flatfoot correction and controls. The second aim was to investigate if there is an impact of individual talus morphology on the success of operative flatfoot correction.

METHODS

We reviewed all patients that underwent lateral calcaneal lengthening for correction of PCFD between 2008 and 2018 at our clinic. Radiographic flatfoot parameters on preoperative and postoperative radiographs were assessed. Additionally, 3-D surface models of the tali were generated using computed tomography (CT) data. The talus morphology of 44 flatfeet was compared to 3-D models of 50 controls without foot or ankle pain of any kind.

RESULTS

Groups were comparable regarding demographics. Talus morphology differed significantly between PCFD and controls in multiple aspects. There was a 2.6° increased plantar flexion (22.3° versus 26°; p = 0.02) and medial deviation (31.7° and 33.5°; p = 0.04) of the talar head in relation to the body in PCFD patients compared to controls. Moreover, PCFD were characterized by an increased valgus (difference of 4.6°; p = 0.01) alignment of the subtalar joint. Satisfactory correction was achieved in all cases, with an improvement of the talometatarsal-angle and the talonavicular uncoverage angle of 5.6° ± 9.7 (p = 0.02) and 9.9° ± 16.3 (p = 0.001), respectively. No statistically significant correlation was found between talus morphology and the correction achieved or loss of correction one year postoperatively.

CONCLUSION

The different morphological features mentioned above might be contributing or risk factors for progression to PCFD. However, despite the variety of talar morphology, which is different compared to controls, the surgical outcome of calcaneal lengthening osteotomy was not affected.

LEVEL OF EVIDENCE

III.

Total and unicondylar knee arthroplasty are equivalent treatment options in end-stage spontaneous osteonecrosis of the knee, and the size of the lesion has no influence on the results

PURPOSE

The purpose of the present study was to compare total (TKA) and unicondylar (UKA) knee arthroplasty for spontaneous osteonecrosis of the knee (SONK), and to investigate potential correlations to radiographic parameters.

METHODS

All consecutive patients with a magnetic resonance imaging (MRI) proven SONK treated with either TKA or UKA between 2002 and 2018 were analysed. The primary outcomes were postoperative complications and failure rates. Functional assessment included Knee Society Score (KSS), WOMAC Score, and range of motion. A novel three-dimensional measurement method was established to determine the size of the osteonecrotic lesion. All outcome parameters were correlated to the size of the necrotic lesion using Spearman's rank correlation.

RESULTS

The two treatment groups (34 TKAs, 37 UKAs) did not differ regarding age, body mass index, and ratio of the volume of the necrotic lesion to the volume of the femoral condyle (n.s.). At a mean follow-up of 6.6 years, patients with UKA had better functional outcomes compared to patients with a TKA (WOMAC Score 1.0 vs. 1.6, p = 0.04; KSS pain 86 vs. 83, n.s), with a similar complication rate. No correlation was found between necrotic lesion size and failure rate (n.s.).

CONCLUSION

UKA is a valuable treatment option for SONK leading to good functional results and a low failure rate. In case of a surgeon's concern regarding implant anchorage, TKA represents an equivalent solution. The MR-tomographic size of the osteonecrotic lesions seems to have no influence on the results.

LEVEL OF EVIDENCE

III.

Factors influencing functional internal rotation after reverse total shoulder arthroplasty

Background

Functional internal rotation (fIR) of the shoulder is frequently limited after reverse shoulder arthroplasty (RTSA). The objective of this study was to study a cohort of satisfied patients after RTSA who had comparable active mobility except for fIR and to identify factors associated with selective loss of fIR.

Methods

A retrospective cohort study was conducted to compare 2 patient groups with either poor (≤ 2 points in the Constant-Murley score [CS]) or excellent (≥8 points in CS) fIR after RTSA at a minimum follow-up of 2 years. Influencing factors (demographic, surgical or implant related, radiographic parameters) and clinical outcome were analyzed.

Results

Fifty-two patients with a mean age of 72.8 (±9.3) and a mean follow-up of 41 months were included in the IR≤2 group and 63 patients with a mean age of 72.1 (±8.0) and a mean follow-up of 59 months in the IR≥8 group. All patients had undergone RTSA with the same implant type and only 2 different glenosphere sizes (36 and 40) for comparable indications. A multivariate analysis identified the following significant risk factors for poor postoperative fIR: poor preoperative fIR (pts in CS: 3 [range: 2-6] vs. 6 [range: 4-8], P<.0001), smoking (17.3% vs. 6.5%, P = .004), male gender (59.6% vs. 31.7%, P = .002), less preoperative to postoperative distalization of the greater tuberosity (Δ 19.4 mm vs. 22.2 mm, P = .026), a thin humeral insert (≤3 mm: 23.1% vs. 54.8%, P = .039), and a high American Society of Anesthesiologists score (≤ III: 30.8% vs. 14.3%, P = .043). Subscapularis repair status and glenosphere size had no influence on fIR. Clinical outcome scores improved in both groups from preoperatively to last follow-up. The IR≥8 group had overall significantly better outcome scores compared to the IR≤2 group (Δ 9.3% SSV and Δ 9.5% relative CS, P < .0001). There was no difference in CS between the cohorts when the score for fIR was discarded.

Conclusion

Independent risk factors for poor postoperative fIR after RTSA are poor preoperative fIR, smoking, male gender, less preoperative to postoperative distalization of the greater tuberosity, a thin humeral insert height, and a high American Society of Anesthesiologists score. Except for male gender, these factors are modifiable. These findings may be a valuable addition to patient counselling as well as preoperative planning and preoperative and intraoperative decision-making. The relevance of fIR for overall satisfaction is substantiated by this study.

Is the contralateral lesser trochanter a reliable reference for planning of total hip arthroplasty - a 3-dimensional analysis

Background

Preoperative templating in total hip arthroplasty (THA) is mandatory to achieve appropriate offset and leg length equality. However, templating methods using the contralateral hip might be susceptible to errors resulting from side-differences in the femoral morphology. The distance of the lesser trochanter to the femoral head center (LTFHD) is a frequently used reference parameter for preoperative planning and intraoperative validation during THA. However, currently no three-dimensional (3D) analysis of side differences of the LTFHD exists.

Methods

Using Computer tomography (CT)-based surface models from 100 paired femora (50 cadavers), side-to-side asymmetry of the LTFHD, femoral length, femoral head diameter (FHD) and femoral antetorsion were analyzed. Univariate linear regression models were established to evaluate potential associations between sides regarding LTFHD and FHD as well as a correlation of these parameters with each other.

Results

Statistically significant side-differences were found for the LTFHD (p = 0.02) and FHD (p = 0.03) with a mean absolute side-difference of 1.6 ± 1.4mm (range 0.1–5.5mm) and 0.4mm ± 0.6mm (range 0–3mm), respectively. The ratio between the LTFHD and FHD was consistent with an average value of 1.16 ± 0.08 and reliable between sides with a correlation coefficient (r) of 0.72 (p < 0.01).

Conclusions

The LTFHD is a reliable reference parameter for preoperative templating and intraoperative validation during THA with a high correlation between sides (r = 0.93, p < 0.01). However, 8 % of the investigated specimens revealed a LTFHD of more than 4mm, which should be anticipated during THA to avoid unsatisfiable results.

Mid-term subsidence and periprosthetic radiolucency of the AMIStem: a 5-year EBRA-FCA analysis

Background

There has been an evolution in cementless total hip arthroplasty (THA) with newer short stem designs aimed to preserve metaphyseal bone stock and facilitate implantation through minimally invasive approaches. While early subsidence has been correlated to aseptic loosening in conventional stems, there is a paucity of data regarding short stems. The current study aims to report on stem subsidence and mid-term clinical outcomes of a cementless, metaphyseal-anchored short femoral stem, specifically designed for the direct anterior approach (DAA).

Methods

Ninety-four consecutive patients (100 hips) with a minimum follow-up of 5 years following cementless THA were included in this single-center retrospective study. Subsidence was evaluated using the “Ein-Bild-Roentgen-Analyse” (EBRA). Periprosthetic radiolucency allocated to the zones of Charnley and Gruen was assessed. Additionally, demographic and implant-related factors potentially associated with increased subsidence and clinical outcomes were evaluated.

Results

At the last follow-up, the average stem subsidence was 1.98 ± 1.20 mm, with 48% of the implants demonstrating subsidence of > 2 mm. Periprosthetic radiolucency of > 2 mm was found in 26% of the implants in zone 1 and in 9% in zone 7, respectively. Neither the amount of subsidence nor proximal periprosthetic radiolucency was associated with aseptic loosening or worse clinical outcomes.

Conclusions

Comparable to other proximally fixed short stem designs, the highest subsidence was observed within the first 3 months following implantation. No demographic or implant-related factors were found to have a statistically significant influence on stem subsidence. Periprosthetic radiolucency and subsidence of the AMISstem is not correlated with worse clinical outcomes at 5-year follow-up.

Arthroscopic-Assisted Anterior Latissimus Dorsi Transfer for Irreparable Anterior Rotator Cuff Tear: A Technical Note

Several reconstruction techniques for irreparable tears of the subscapularis tendon have been described with variable results regarding pain relief, functional recovery, and dynamic stabilization of the glenohumeral joint. Because of a more advantageous direction of movement compared with previously described transfer techniques such as transfer of the pectoralis major and pectoralis minor tendons, the anterior latissimus dorsi (LD) transfer has been proposed as a potentially beneficial treatment method. This Technical Note aims to introduce an alternative technique for the anterior LD transfer that combines the advantages of a proper muscle release and tendon reinforcement through an axillary incision with the arthroscopic intra-articular and periarticular work, including detachment of the LD tendon from its humeral insertion and reattachment at the lesser tuberosity.

Clinical and radiological mid- to long-term results after direct fixation of posterior malleolar fractures through a posterolateral approach

BACKGROUND

Direct fixation of posterior malleolar fractures has been shown to lead to higher accuracy of fracture reduction compared to an indirect anterior to posterior fixation but lacks long-term clinical results. This study shows the mid- to long-term clinical and radiological outcome after direct fixation of the posterior malleolus through a posterolateral approach.

MATERIALS AND METHODS

Thirty-six patients with an ankle fracture including a posterior malleolar fragment (23 × AO-44C, 12 × AO-44B, 1 × unclassifiable) treated with direct fixation of the fragment through a posterolateral approach were retrospectively evaluated. There were 24 females (67%) with a mean age of 63 (range 34-80) years and a BMI of 28 (range 19-41) kg/m² at the time of surgery. An initial fracture-dislocation was seen in 67%. The clinical outcome was assessed with the Visual Analog Scale (VAS, 0-10 points) and the American Foot and Ankle Society (AOFAS, 0-100 points) score. Posttraumatic osteoarthritis was recorded with the Van Dijk Classification (grade 0-III). Subgroup analyses of patient- and fracture-associated risk factors (age, BMI, smoking, fracture-dislocation, postoperative articular step-off) were assessed to reveal possible negative prognostic predictors.

RESULTS

After a mean follow-up of 7.9 (range 3-12) years, the median VAS was 1 (IQR 0-2) point, and the median AOFAS score was 96 (IQR 88-100) points. Ankle range of motion measurements showed a significant, but clinically irrelevant, difference in plantar- and dorsiflexion between the affected and unaffected ankle. 92% of the patients were very satisfied or satisfied with the postoperative course. 89% had no preoperative signs of ankle osteoarthritis. Osteoarthritis progression was seen in 72%, with 50% showing grade II or III osteoarthritis at the final follow-up. No significant negative prognostic factors for a worse clinical outcome could be detected.

CONCLUSION

Direct fixation of posterior malleolar fractures through a posterolateral approach showed good clinical mid- to long-term results with a high satisfaction rate but substantial development of posttraumatic ankle osteoarthritis. Further studies should include CT analysis of the preoperative fracture morphology and even, perhaps, the postoperative reduction accuracy to evaluate the benefit of posterior malleolar fracture reduction in preventing ankle osteoarthritis in the long term.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for authors for a complete description of levels of evidence.

Is revision total hip arthroplasty through the direct anterior approach feasible?

BACKGROUND

To date, only limited literature exists regarding revision of total hip arthroplasty (THA) through the direct anterior approach (DAA). However, as the popularity of the DAA for primary surgery is increasing, surgeons will be confronted with the challenge of performing revision surgery through the DAA. The aim of this study was to review the potential of the DAA in the revision setting and to report the clinical results, radiologic outcomes and complication rates of 63 patients undergoing revision THA through the DAA.

METHODS

From 01/2009 to 08/2017, 63 patients underwent revision THA through the DAA. Depending on the performed procedure, patients were separated into 4 groups: liner and head exchange (21 patients), revision of the acetabular cup (26 patients), revision of the femoral stem (13 patients) or revision of both components (3 patients). Postoperative complications as well as the clinical and radiological outcome were assessed retrospectively.

RESULTS

At a mean follow-up of 18 months, the overall complication and re-operation rates were 14.3% and 12.7%, respectively. Specifically, the complication and re-operation rates were 14.2% and 9.5% after liner and head exchange, 15.4% after revision of the acetabular cup, 15.3% after revision of the femoral stem and 0% after revision of both components. The mean postoperative HHS at 1 year postoperatively was 91 (range 74-100).

CONCLUSION

The DAA offers appropriate exposure for exchange of mobile liners and acetabular cup revision. In selected cases with appropriate stem design, femoral stem revision through the DAA is feasible. However, surgeons should be aware of the technical difficulties related to femoral revision and be prepared to extend the approach distally or perform a trochanteric osteotomy.

Should advanced age be a contraindication to total hip arthroplasty in femoral neck fracture patients? A matched-control, retrospective study

Introduction

Due to demographic changes, the annual incidence of femoral neck fractures (FNF) in patients reaching the 9th and 10th decade of life is increasing. Although active and cognitively intact elderly patients could benefit from total hip arthroplasty (THA) in case of a FNF, there is no clear consensus on whether THA should be performed in this particular subgroup of patients with very advanced age. The purpose of this study was to report the complication rate, mortality, clinical outcomes and quality-adjusted life year (QALY) gained in patients treated with total THA for FNF, while having exceeded the mean life expectancy at the time of surgery, compared to a younger control group.

Materials and Methods

Patients treated with THA through a direct anterior approach (DAA) for FNF and exceeding the average life expectancy in Switzerland (age ≥ 83 y, n = 45) were matched for gender, body mass index (BMI) and ASA score with patients under the age of 83 (age = 65-83, n = 45). Perioperative complications, clinical and radiologic outcomes, as well as mortality were compared between groups.

Results

Total complication rate did not differ significantly with 22.2% in the older group compared to 17.8% in the control group. The 30-day and 1-year mortality was slightly but not significantly higher in the older group (2.2% and 8.9% vs. 2.2% and 2.2%). The average QALY gained was 3.4 years and 4.1 years for the older group and their younger counterparts, respectively.

Conclusion

THA through the DAA for FNF in cognitively intact and active patients might be a credible and safe option even after reaching mean life expectancy with excellent functional outcomes and similar surgery-related complications compared to patients younger than 83 years. Our results imply that an advanced age should not be considered a contraindication for THA in case of a FNF.

Midterm clinical and radiographic outcomes of 115 consecutive patient-specific unicompartmental knee arthroplasties

BACKGROUND

Poor implant positioning has been identified as a factor in early failure of unicompartmental knee arthroplasty. The aim of this study was to report the accuracy of component positioning, and midterm clinical, functional and radiological outcomes following patient-specific instrumented (PSI) unicompartmental knee arthroplasty (UKA).

METHODS

A total of 115 PSI-UKA were included. The primary outcomes were UKA survival, complication, and failure rates. Tibial implant positioning was determined using plain radiographs. Functional assessment included Oxford Knee Score (OKS), Forgotten Joint Score (FJS), patient satisfaction, and range of motion (ROM).

RESULTS

The survival rate of PSI-UKA was 92% after a mean follow-up of 55 months. The complication and failure rate was 13% and eight percent, respectively. The tibial component was accurately implanted in the desired frontal and sagittal alignment with a minor deviation of 0.3° (SD 1.9°) and 0.4° (SD 2.6°) to the preoperative planning. OKS increased from 24 (SD eight) points to 44 (SD six). FJS was 87 (SD 23) and 89.6% of all patients reported to be satisfied at the final follow-up. Patient satisfaction was negatively correlated with patients' age (p < 0.05).

CONCLUSION

Excellent accuracy regarding component placement in UKA can be achieved with PSI. However, despite excellent survivorship and clinical outcomes, these data indicate that the PSI system is not superior to conventional UKA implantation methods.

The Role of Total Hip Arthroplasty Through the Direct Anterior Approach in Femoral Neck Fracture and Factors Affecting the Outcome

BACKGROUND

Femoral neck fractures (FNFs) are a significant cause of mortality and disability among the elderly population. Total hip arthroplasty (THA) is the preferred treating method in active, cognitively intact patients. The direct anterior approach (DAA) has suggested a lower dislocation risk and a significant reduction in postoperative pain and recovery time in elective THA. This study aimed to compare clinical outcomes, perioperative complications, and mortality of THA through the DAA between FNF and elective cases.

METHODS

Patients with displaced FNF (n = 150) who received THA through the DAA were matched for gender, age, body mass index, and American Society for Anesthesiologists score with electively treated patients (n = 150). The perioperative complications, clinical and radiologic outcomes, as well as mortality were compared between groups, retrospectively.

RESULTS

FNF patients had an increased blood loss, operation duration, hospital stay, and mortality but similar surgery-related complication rates compared to their elective counterparts. The mortality was, however, lower than that reported in the literature. Age, American Society for Anesthesiologists score, and time-to-operation affected the duration of hospital stay and mortality. Less experienced surgeons did not have increased surgery-related complications, but longer operation time and higher blood loss compared to experienced surgeons.

CONCLUSION

THA through the DAA might be a credible and safe option for patients presenting an FNF, with excellent functional outcomes, less surgery-related complications, and lower short-term and long-term mortality than those reported in the literature. Early intervention and perioperative stabilization of the patients with FNF could potentially increase the survival rate.

Is Direct Anterior Approach a Credible Option for Severely Obese Patients Undergoing Total Hip Arthroplasty? A Matched-Control, Retrospective, Clinical Study

BACKGROUND

Severely obese patients present a significant challenge for arthroplasty surgeons because of their body habitus. Up to date, there is no clear consensus on the safety of the direct anterior approach (DAA) in obese patients undergoing total hip arthroplasty. Therefore, the purpose of the present study was to determine whether DAA is a credible option in severely obese regarding complication rates, clinical outcomes, and component positioning.

METHODS

Obese patients with a body mass index ≥ 35 kg/m² (n = 129) who received total hip arthroplasty with DAA in our institution were matched for gender and age with nonobese patients with body mass index ≤ 25 kg/m² (n = 125). The postoperative complications and clinical and radiologic outcomes were assessed retrospectively.

RESULTS

The results of this study showed an increased risk of reoperation (relative risk: 4.0), mostly due to wound infection and dehiscence, in obese than in nonobese patients. The mean Harris Hip Score increased from 50 and 42 preoperative to 95 and 97 at the 1-year follow-up in obese patients and nonobese patients, respectively. No significant difference was observed regarding the acetabular anteversion, inclination or leg-length discrepancy, and vertical center of rotation. The horizontal center of rotation was slightly medialized (4 mm) in the nonobese compared with the obese patients (1 mm).

CONCLUSION

Obese patients had a higher complication and reoperation rate compared with nonobese patients. However, these rates were comparable to the rates of the standard, more extensive approaches presented in the literature. The current data suggest that DAA might be a credible option for obese patients, with excellent functional and radiographic outcomes.

[Conclusions and recommendations of a WHO expert consultation meeting on iron supplementation for infants and young children in malaria endemic areas]

This article presents the results of an expert consultation meeting aimed at evaluating the safety and public health implications of administering supplemental iron to infants and young children in malaria-endemic areas. Participants at this meeting that took place in Lyon, France on June 12-14, 2006 reached consensus on several important issues related to iron supplementation for infants and young children in malaria-endemic areas. The conclusions in this report apply specifically to regions where malaria is endemic.

The implementation of evidence-based medicine in general practice prescribing

BACKGROUND

Research on the implementation of evidence-based medicine has focused on how best to influence doctors through information and education strategies. In order to understand the barriers and facilitators to implementation, it may also be important to study the characteristics of those doctors and practices that successfully implement evidence-based changes.

AIM

To determine the relationship between practice and doctor characteristics and the implementation of recommended evidence-based changes in the area of prescribing.

METHOD

Visits were made to 39 practices in southern England. Audits of three key prescribing changes were carried out and amalgamated to produce an 'implementation score' for each practice. These scores were related to a wide range of practice and doctor variables obtained from a questionnaire survey of doctors and practice managers.

RESULTS

There was wide variation between the practices' implementation scores (mean 67%, range 45% to 88%). The only factors that had a significant relationship with implementation of these important prescribing changes were an innovative approach among the doctors (most practitioners were cautious of change), and fundholding status. Use of clinical protocols, disease registers, or computers was not associated with overall implementation score, nor was the doctor's age. Doctors complained of information overload.

CONCLUSIONS

The emphasis on the need for evidence in medicine, and better transmission of information, needs to be balanced by a recognition that most general practitioners are pragmatic, averse to innovation, and already feel overwhelmed with information. Important advances in therapy may be crowded out. More attention should be given to the facilitation of priority changes in practices.

The career outcomes for doctors completing general practice vocational training 1990-1995

BACKGROUND

While much has been published about the career outcomes of doctors who completed general practice vocational training prior to 1990, no evidence is currently available about those who have qualified since that time.

AIM

To obtain information about the career paths of doctors who had completed general practice vocational training since 1990, and to compare the results with previously published data.

METHOD

Postal questionnaire survey of all doctors completing vocational training during the period 1990-1995 in three regions of the United Kingdom. The study examined current work status, career path since completion of training, desire for and experience of part-time training, degree of difficulty in choosing and following a career, and the degree to which certain factors impeded career choice.

RESULTS

The overall response rate was 64.8%, although there was a significant difference between the response rates for men and women. While virtually all responders were employed, with the majority working in general practice, women were significantly less likely than men to be working as principals in general practice, for all cohorts. These results were very similar to those cohorts described in earlier studies. The career paths of doctors only became stable after about four years. Of those working in general practice, about 20% found it difficult to choose their career, and about 10% found it difficult to follow their career. Out-of-hours work was the major factor impeding career choice.

CONCLUSION

Although they are taking longer to reach, the final career destinations of doctors completing vocational training since 1990 are no different from those of earlier cohorts.

Content validity of a trainer's report: summative assessment in general practice

A structured trainer's report for use in summative assessment in general practice has been designed, and it is important that the content validity of this report is tested before it is widely adopted. The aim of this paper was to assess the content validity of a proposed report from the perspective of doctors who have recently completed vocational training. A postal questionnaire survey was sent out seeking the views of 220 doctors who had completed vocational training in 1994 as to whether or not the proposed contents were items that are needed in general practice, and whether or not the items were suitable for assessment by means of a trainer's report. The response rate was 73.3%. More than 85% of respondents agreed that the 31 items proposed for inclusion in the trainer's report were needed in general practice. While the proportions agreeing that the items were suitable for assessment by a trainer's report were considerably lower, for 26 items significantly more agreed that they were suitable than disagreed. Analysis of the freetext comments made by respondents illustrated their concerns. The results provide support for the content validity of this proposed trainer's report; however it is important that the concerns expressed are addressed.

A novel mutant variant of the CYP2D6 gene (CYP2D6*17) common in a black African population: association with diminished debrisoquine hydroxylase activity

1. The debrisoquine hydroxylase (CYP2D6) is polymorphically distributed. Not only are there differences in the proportions of extensive metabolisers to poor metabolisers in various ethnic groups, but there are also pronounced variations in the metabolic capacity among those classified as extensive metabolisers. 2. The mean debrisoquine metabolic ratio of Caucasian extensive metabolisers is lower than that for a number of African populations. In the present study, we have searched for novel CYP2D6 mutations to explain the diminished enzyme activity in African populations. 3. Three Zimbabwean Shona subjects with EM phenotypes (metabolic ratios for debrisoquine of 0.4, 1.5 and 10.5 respectively) were selected and the open reading frame of the CYP2D6 gene of each was sequenced. 4. The subject with metabolic ratio of 10.5 was found to be homozygous for an allele with a nucleotide exchange in exon 2, 1111C-->T causing a 107Thr-->Ile amino acid exchange in a conserved region of the enzyme. In addition, he was homozygous for the 2938C-->T and 4268G-->C mutations causing 296Arg-->Ser and 486Ser-->Thr amino acid substitution found in the CYP2D6*2 allele. 5. Seventy-six Zimbabwean Shona subjects were subsequently genotyped for the 1111C-->T mutation and for the intron 1 gene conversion present in the CYP2D6*2 gene. The 1111C-->T mutation was found at an allele frequency of 34% and was only present in alleles carrying the gene conversion in intron 1 indicative for the CYP2D6*2 gene. 6. This allele (CYP2D6*17), containing the 1111C-->T, 2938C-->T and 4268G-->C mutations, was found to be strongly associated with lower capacity for debrisoquine hydroxylation. We therefore postulate that the CYP2D6*17 allele might contribute to the molecular basis of the previously established diminished debrisoquine hydroxylase activity in African Bantu populations.

Phenotype and genotype analysis of debrisoquine hydroxylase (CYP2D6) in a black Zimbabwean population. Reduced enzyme activity and evaluation of metabolic correlation of CYP2D6 probe drugs

OBJECTIVE

Debrisoquine hydroxylase (CYP2D6) is responsble for the oxidative metabolism of many clinically used drugs. Since this enzyme has been poorly studied in the southern part of Africa, we examined the CYP2D6 phenotypes and genotypes in 103 unrelated black Zimbabweans.

METHODS

Phenotyping for CYP2D6 activity was done using debrisoquine and metoprolol as probe drugs by measuring the urinary metabolic ratio (MR) of parent drug to metabolite concentration ratios. Genotyping was done using polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP), single-strand conformation polymorphism (SSCP) and sequencing analyses with respect to CYP2D6 variants of interest.

RESULTS AND CONCLUSION

Phenotyping with debrisoquine revealed two poor metabolisers (PMs), whereas 5 subjects out of 94 were PMs using metoprolol as probe drug. Genotypes predictive of the poor metaboliser status were observed for the two subjects who were PMs with both probe drugs, whereas no mutations could explain the PM phenotype for metoprolol among the three remaining subjects, a fact possibly explained by lack of compliance in metoprolol intake. There was a moderate correlation of 0.67 between the debrisoquine and metoprolol metabolic ratios in the 89 subjects who were extensive metabolisers for both probe drugs. The median values for the metabolic ratios for debrisoquine and metoprolol as probe drugs were 1.00 and 1.35, respectively, which are higher than those observed in Caucasian populations. This is indicative of a decreased capacity for metabolism of CYP2D6 substrates by Zimbabweans compared to Caucasians. Evaluation of the DNA samples for the known allelic variants CYP2D6A, CYP2D6B, CYP2D6C, CYP2D6D or CYP2D6Ch1 yielded no explanation for these results.

Content of a trainer's report for summative assessment in general practice: views of trainers

BACKGROUND

Summative assessment of doctors completing general practice vocational training will become compulsory for those completing training after 1 September 1996. One component of the assessment will be a trainer's report.

AIM

A study set out to consider the content of the trainer's report. It aimed to determine which elements of general practice general practitioner trainers believe are the most important for independent general practice; to seek the views of trainers as to the most appropriate methods for assessing these elements in summative assessment of general practitioner registrars; and to determine how frequently trainers have been sufficiently concerned about the performance of registrars to consider not signing the form denoting satisfactory completion of the training year.

METHOD

A questionnaire was sent to 1296 general practitioner trainers in the United Kingdom. The main outcome measures used were: the percentage of respondents indicating that an element was very important/crucial for independent general practice; the percentage of respondents indicating a favoured method of assessment that did not include a trainer's report at all; and the proportion of trainers who had ever considered not signing the form denoting satisfactory completion of the training year.

RESULTS

The response rate was 78%. Of 75 elements examined, 31 were considered important for independent general practice by 70% or more of respondents. For 29 of these 31 elements, fewer than 30% of respondents would choose a method of assessment that did not include a trainer's report at all. Twenty-six per cent of respondents had considered not signing the form denoting satisfactory completion of the training year, which represents a trainer considering not signing this form once every 29 years.

CONCLUSION

These results provide a basis for the content of a structured trainer's report for summative assessment in general practice; such a report is likely to contain about 30 items. Data from the Joint Committee on Postgraduate Training for General Practice and the present study suggest that, for every form not signed, trainers considered not signing the forms of another 13 general practitioner registrars. This highlights the need for a report that will help trainers to make the difficult decision as to whether or not a registrar is ready for independent practice.

Consensus minimum standards for use in a trainer's report for summative assessment in general practice

BACKGROUND

Summative assessment of general practitioner registrars is to be introduced in September 1996, one component of which will be a report by the trainer. Standards must be set and guidance provided as to the most appropriate ways of obtaining evidence for the trainer's assessment.

AIM

The first aim of this study was to set consensus minimum standards for 30 items that are likely to form the content of a trainer's report; the second aim was to provide a consensus view on the most appropriate methods of assessment to be used by trainers.

METHOD

A consensus conference was held in March 1995 during which the 30 items were discussed by a group of 30 general practitioners, of whom 27 were experienced trainers. This resulted in a draft document that was circulated to the conference attenders and other experts for consultation.

RESULTS

Draft minimum standards were produced for all 30 items after the consensus conference with a mean of 2.5 standards for each item. Of those involved in the consultation exercise, 82% replied. Most of the revisions suggested at this stage were of a minor nature; the only major revision was to divide one item into two, resulting in a final total of 31 items. All but one of the 80 standards could be assessed by direct observation; 41 (51%) could be assessed by tutorial-based discussion and 61 (76%) by methods specific to that standard. Trainers or their practice partners were viewed as acceptable sources of evidence for all items and hospital consultants and primary health care team members were viewed as acceptable for just over half of the items.

CONCLUSION

Standards for use by trainers when providing a general practitioner report for the summative assessment of registrars have been developed by consensus conference and have been subjected to review by consultation. Acceptable methods by which registrars could be assessed against these standards, and suitable personnel who could provide evidence, have also been suggested.

General practice careers: changing experience of men and women vocational trainees between 1974 and 1989

The aim of this study was to consider the careers pursued by men and women general practitioner trainees following the completion of their training, and to assess changes since 1974. It was based on a postal questionnaire survey involving 995 doctors who had completed general practice vocational training in the Oxford region between 1974 and 1989. A total of 796 doctors replied to the questionnaire (498 men and 298 women, overall response rate 80%). The vast majority of ex-trainees were working in general practice at the time of the survey (men 87%, women 71%). Women were less likely to have become principals than men (75% versus 97%). Most women (71% of those completing training before 1988) reported at least one period of non-employment. While the duration of maternity leave dropped only slightly during the 15 years studied, the length of voluntary and involuntary unemployment experienced by women fell markedly. Men experienced little unemployment with no change in length of unemployment over time. Considerably fewer women than men (6% versus 13%) had become involved in teaching or training. The degree of difficulty in choosing and following a general practice career remained constant over time for women. In contrast there was a significant increase in the difficulties experienced by men. The proportion of men and women completing training in 1984-89 who found following a general practice career 'difficult or very difficult' was similar (10% of men, 13% of women). The possibility of improving these experiences, particularly by encouraging flexibility in the early years after completion of training, is discussed.

Molecular epidemiology of aflatoxin exposures: validation of aflatoxin-N7-guanine levels in urine as a biomarker in experimental rat models and humans

Human epidemiology and experimental animal data have provided the statistical association and biological information necessary to propose that aflatoxins are risk factors for human liver cancer. As liver cancer causes at least 200,000 deaths per year, prevention measures must be developed to ameliorate this nearly always fatal disease. Preventive strategies will be facilitated by the identification of individuals at high risk. It is the goal of the molecular dosimetry field to provide facile and accurate biomarkers to identify people at high risk for carcinogen exposure and consequent adverse health effects. We have developed methods to defect the major aflatoxin DNA adduct, aflatoxin N7-guanine (AFB-N7-guanine), in urine, examined the dose-response characteristics in people living in China and The Gambia, and have found an excellent association of this biomarker with exposure. In addition to exposure studies in people, our laboratories have monitored AFB-N7-guanine excretion in the urine of rats whose risk for developing cancer has been modulated with dietary chemoprotective agents such that independent groups of animals receiving the same dosage of aflatoxin B1 were at either high or low risk for tumorigenesis. The production of DNA damage by aflatoxins is not the exclusive mechanism for liver cancer. Many other factors, including hepatitis B virus, cell proliferation, and nutritional status, can exert strong modification effects in human disease. Thus, molecular epidemiological investigations that examine only one biomarker may greatly underestimate or overestimate the risk for an individual.(ABSTRACT TRUNCATED AT 250 WORDS)

The primary health care team: history and contractual farces

Images

Training for minor surgery in general practice during preregistration surgical posts

OBJECTIVE

To study the teaching of minor surgery to preregistration house officers in surgery and their confidence in their skills.

DESIGN

Questionnaire survey of consultants and vocational trainees.

SETTING

Trent, Oxford, and East Anglian Regional Health Authorities.

SUBJECTS

All consultant surgeons (n = 148) with preregistration house officers on their firm and all first year vocational trainees in general practice (n = 165).

MAIN OUTCOME MEASURES

Time spent teaching minor surgery to preregistration house officers; source of teaching; trainees' confidence in their skills in 15 minor surgical procedures and degree of confidence that consultants expected their junior house officers to achieve.

RESULTS

137 (93%) consultants and 139 (84%) vocational trainees replied; 131 of the consultants' replies and all the trainees' replies were analysable. Only 14 consultants had a curriculum for teaching junior house officers, and 90 offered less than four hours' teaching a week. Only 11 trainees thought that their firm had had a curriculum, and 102 reported having received under two hours' teaching a week. The consultants indicated that they did most of the teaching, but the trainees reported having received most of their teaching from junior registrars. Seventy nine consultants attempted to teach minor surgery. They expected their junior house officers to acquire greater confidence in their skills in minor surgery than did the other consultants, but overall the confidence expected was low. The trainees were more confident than the consultants expected them to be, but overall confidence was still low. Those who had received more teaching were significantly more confident.

CONCLUSIONS

The educational potential of the post of preregistration house officer in surgery seems underexploited, particularly with regard to teaching skills in minor surgery.

Effect of dietary crude-protein type on fertilization and embryo quality in dairy cattle

An experiment was conducted to determine whether balancing dietary crude protein for optimal rumen degradability would improve fertilization rate and quality of ova in lactating dairy cows. Thirty-eight Holstein cows in early lactation were fed 1 of 2 diets formulated to be isocaloric and isonitrogenous, containing 16% crude protein. Diet 1 contained 73% rumen degradable intake protein, whereas diet 2 contained 64% rumen degradable intake protein. The cows were induced to superovulate and were inseminated, and ova were recovered nonsurgically on postbreeding day 7. Ova were counted and classified as fertilized or unfertilized. Fertilized ova were scored as excellent, good, fair, poor, or degenerate. Unfertilized ova and poor and degenerate embryos were considered to be nontransferable ova and excellent, good, and fair embryos were considered to be transferable ova. There were no differences for mean number of fertilized, unfertilized, transferable, or nontransferable ova recovered from cows fed the 2 diets (P greater than 0.10). Mean percentage of fertilized ova recovered from cows was greater (P less than 0.05) in those fed diet 2, compared with diet 1. Mean percentage of transferable ova recovered from cows tended to be greater (P = 0.06) in those fed diet 2, compared with diet 1. More cows failed to yield transferable ova (P less than 0.05) when fed diet 1, compared with diet 2. Fertilization failure or early degeneration of embryos may occur in cows fed excess rumen degradable protein.

Changes of the surface proteolytic activity in synchronized Ehrlich ascites tumor cells grown in vivo

Changes of the cell surface proteolytic activity during the cell cycle in vitro were reported. Using an easy assay, with casein as a substrate, the proteolytic activity on the surface of Ehrlich ascites tumor (EAT) cells grown in vivo was determined. The cleavage of casein incubated with EAT cells increased linearly for 20 min and permitted reproducible enzyme activity determinations. If the proliferation of exponentially growing EAT cells was partially synchronized by an intraperitoneal bleomycin injection, a significant increase of the surface enzymatic activity was observed in cells with an increased DNA content. This finding supports the results obtained with transformed cells in vitro, indicating that elevated proteolytic surface activity occurs in the late synthesis phase and prior to mitosis. However, the observed effect may also be due to changes of gene expression caused by bleomycin.