Clinical Outcome After Replacement of Distal Femur/Proximal Tibia in a Heterogeneous Patient Cohort: Function Following Tumour, Trauma, and Loosening

BACKGROUND

Distal femur and proximal tibia replacements as limb-salvage procedures with good outcome parameters for patients with tumours have been broadly described. However, the overall midterm outcome in a mixed, heterogeneous patient collective is still unclear.

PATIENTS AND METHODS

We retrospectively analysed 59 consecutive patients (33 for primary and 26 for revision surgery) between 1998 and 2017. Indication for implantation was tumour (n=16), periprosthetic fracture (n=14), traumatic fracture (n=14), infection (n=10), aseptic loosening (n=3), and pathological fracture (n=2). The mean follow-up duration was 3 years. Clinical functions were evaluated by Toronto Extremity Salvage Score and Knee Society Score. Knee extension and flexion force were measured.

RESULTS

The overall survival rate of arthroplasties was 59% (n=35). Major complications were observed in 36 (61%) patients. During the follow-up period, 14 (24%) patients died. We recorded periprosthetic joint infection in 21 (36%) patients, recurrence of tumour in two (3%), and aseptic implant failure in three (5%). The mean Toronto Extremity Salvage Score was 66±33, and the mean Knee Society Score was 49±30. The mean extension force on the operated side was significantly reduced at 60° and 180° compared to the healthy side (p=0.0151 and p=0.0411, respectively).

CONCLUSION

Distal femur and proximal tibia replacements showed limited clinical function in a heterogeneous patient collective. Indication for implantation should be considered carefully.

Reduction of Patella-baja and Pseudo-patella-baja Does Not Improve Range of Motion in Patients After Mega-TKA

BACKGROUND/AIM

Patella baja (PB) and pseudo-patella baja (PPB) have been shown to negatively influence outcomes after total knee arthroplasty. We hypothesized that there is a high incidence of PB and PPB after megaprosthetic total knee arthroplasty (M-TKA), and that this is associated with reduced range of motion.

PATIENTS AND METHODS

We retrospectively analysed all patients in our Orthopaedic Trauma Department after distal femur or proximal tibia replacement. Preoperative and one-year postoperative follow-up included measurement of range of motion and detection of PB and PPB using radiological indices.

RESULTS

We included 44 patients (age: 73±19 years). Preoperative PB detected by ISI could be reduced from 13 (36%) to 11 (25%) (p<0.01). Preoperative vs. postoperative ISI was 0.88±0.23 vs. 1.06±0.45 (p=0.03). PPB was observed preoperatively in 23 (63%) patients vs. 24 (54%) postoperatively. Preoperative vs. postoperative CDI was 0.70±0.24 vs. 0.95±0.43 (p=0.002). Preoperative flexion was 91°±30° vs. 85°±24° postoperatively (p>0.05).

CONCLUSION

Both PB and PPB are frequently observed after M-TKA. A reduction in PB and PPB alone does not improve postoperative range of motion.

Sarcopenia (SMI(+)) in patients (pts) with advanced or metastatic soft tissue sarcoma (a/mSTS): Potential parameter for risk prediction during multimodal therapy (MT)?

11069

Background: Objective parameters identifying ideal pts for MT from pts with a/mSTS remain scarce. Here, we analysed the impact of sacropenia in a/mSTS pts on treatment outcome of MT, retrospectively. Methods: Pts. with a/m STS treated at our centre (12/98-5/16ere identified. 89/181 pts were evaluable for analysis (CT-scans: -14 days before MT onset). Lumbar skeletal muscle index (SMI) was measured with MeVisLab 2.7 by manually segmentation of preinterventional CTs. SMI cut-off were defined through optimal fitting method (sarcopenia = SMI(+) in male: < 44 , in female: 38). Progression was defined by clinical or radiological judgment. Descriptive statistics, Kaplan-Meier-analysis and Cox-regression were administered. Results: At MT onset 28/89 pts (31%) suffered from sarcopenia, and SMI(+) pts were older than SMI(-) pts (p = 0.025). SMI(+) pts tends to receive lower numbers of medical treatments, received less often surgery, and more frequently radiotherapy, although differences were not significant. Further on, SMI(+) pts tends to profit less from first line medical treatment, compared to SMI(-) pts (objective responses: 14,3% vs. 27.9%, p = .161, clinical benefit rate: 25% vs. 65.6%, p = .032, PFS: 1 (95%-CI:.35-1.65) vs. 16 (95%CI:8.8-23.2) months, p = .002). OS was inferior in SMI(+) compared to SMI(-) pts. (4 (95%CI:2-6) vs. 16 (95%CI:8.8-23.2), p = .002). Multivariable analysis showed a trend for SMI(+) to be associated with PFS (HR: 1.7 (95%CI: 0.9-2.8), p = .067) and were independently associated with OS (HR: 2.53 (95%CI: 1.5-4.2), p < .001). Conclusions: In our cohort sarcopenia tends to be associated with less aggressive therapy in a/mSTS pts. However, sarcopenia tends to be associated with inferior PFS and was identified as independent risk factor for inferior OS. Although this analysis is limited due to its sample size sarcopenia might offer an attractive tool as guidance for treatment intensity modulation in a/mSTS patients, avoiding overtreatment in this cohort with dismal prognosis.

Intraoperative computer-assisted prediction of intraarticular contact pressures in the knee during high tibial osteotomy

OBJECTIVES

To develop an accurate intraoperative method to estimate changes in intraarticular contact pressures during high tibial osteotomy (HTO).

METHODS

Changes in knee alignment and pressure were monitored in real time in seven cadaver specimens that received HTO. Intraarticular contact pressure (N/mm² ) in each knee compartment was estimated based on extraarticularly acquired data (leg alignment, correction, and ankle tilt) and based on the application of an axial force of half bodyweight (400-450 N).

RESULTS

Contact pressure estimation was more accurate in the lateral compartment (R²  = 0.940) than in the medial compartment of the knee (R²  = 0.835). The optimism-corrected R² was 0.936 for the lateral compartment and 0.821 for the medial compartment.

CONCLUSIONS

We have established a framework for estimating the change in intraarticular contact pressures based on extraarticular data. This research could be helpful in generating appropriate algorithms to estimate joint alignment changes based on applied loads.

[Injury prevention in amateur football with FIFA 11+ : What is implemented on the football pitch?]

BACKGROUND

The warm-up and injury prevention program FIFA 11+ was developed to reduce injuries in recreational and amateur level football. Despite systematic education it is uncertain what amount of knowledge is passed down to the lower recreational level football players and what exercises are implemented in the daily routine. This study presents the summarized experiences of German coaches about the implementation of exercises on the football pitch.

MATERIAL AND METHODS

In this study 142 coaches who participated in 1 (of 5) of the 2‑day courses between 2013 and 2017 were sent a questionnaire. The questionnaire consisted of 24 questions, which were developed by the football union of Lower Saxony. Incomplete questionnaires were excluded from the study.

RESULTS

A total of 121 questionnaires could be analyzed, which is a response rate of 85.2%. The mean time period between the 2‑day training and answering the questionnaire was 29 months. Of the participating coaches 82.6% indicated that they use the program regularly (22% of the coaches use it twice a week or more frequently, 34% use it only once a week) and 6% of the coaches use additional programs to prevent injuries. A total of 86% of the participants believed in a reduction in the incidence of injuries induced by the FIFA 11+ concept, 89% of the participants rated the FIFA 11+ program as good ors very good, 91% rated the teaching concept as good or very good and 94% of the participants would recommend the 2‑day advanced course to others.

DISCUSSION

The prevention program as well as the advanced training concept were evaluated very positively. Most coaches use the program regularly. Nevertheless, many coaches use the FIFA 11+ exercises less than the recommended twice a week. Most coaches praised the good structure of the program, but also wished for the possibility of variations.

CONCLUSION

The prevention program FIFA 11+ is seen by coaches in recreational and amateur football as an effective tool to prevent injury. Implementation on the football pitch is regular but not as frequent as the evidence-based recommendations in the training concept.

Long-term outcome in 324 polytrauma patients: what factors are associated with posttraumatic stress disorder and depressive disorder symptoms?

Background

Physical impairment is well-known to last for many years after a severe injury, and there is a high impact on the quality of the survivor’s life. The purpose of this study was to examine if this is also true for psychological impairment with symptoms of posttraumatic stress disorder or depression after polytrauma.

Design

Retrospective cohort outcome study.

Setting

Level I trauma centre.

Population

637 polytrauma trauma patients who were treated at our Level I trauma centre between 1973 and 1990. Minimum follow-up was 10 years after the injury.

Methods

Patients were asked to fill in a questionnaire, including parts of the Posttraumatic Stress Diagnostic Scale, the Impact of Event Scale-Revised and the German Hospital Anxiety and Depression Scale, to evaluate mental health. Clinical outcome was assessed before by standardised scores.

Results

Three hundred and twenty-four questionnaires were evaluated. One hundred and forty-nine (45.9%) patients presented with symptoms of mental impairment. Quality of life was significantly higher in the mentally healthy group, while the impaired group achieved a lower rehabilitation status.

Conclusions

Mental impairment can be found in multiple trauma victims, even after 10 years or more. Treating physicians should not only focus on early physical rehabilitation but also focus on early mental rehabilitation to prevent long-term problems in both physical and mental disability.

Fatty degeneration of the deltoid muscle associated with displaced proximal humerus fractures

INTRODUCTION

The use of reverse shoulder arthroplasty (RSA) has increased dramatically over the last two decades, with many surgeons now indicating RSA for the acute management of displaced proximal humerus fractures (PHF) in the elderly. RSA relies on adequate deltoid muscle function to obtain a good outcome, yet no literature to date exists which discusses preoperative assessment of deltoid structure prior to RSA. The purpose of this study was to assess for preoperative fatty deltoid-degeneration in patients with displaced PHF.

MATERIALS AND METHODS

We reviewed the axial CT scans of 100 consecutive patients with a displaced PHF. Fatty degeneration within each of the three deltoid-heads was graded at three levels, according to Goutallier and colleagues. Fractures were classified according to Neer.

RESULTS

Seventy-nine percent of the patients were female, 75% showed 3 or 4 parts fractures. The average cross-sectional area of the posterior deltoid was greatest-representing 37%, 40% and 42% of total area at each level, respectively. Severe fatty degeneration (Stages 3 and 4) was observed in the posterior deltoid only (26%). Absence of fatty degeneration (Stage 0) was observed in < 25% of cases. The Inter-Observer-Reliability for the continuous variables proved to be high.

CONCLUSION

Preoperative deltoid fatty degeneration is common in displaced PHF in the elderly. Because CT is commonly obtained to assess fracture morphology and for preoperative planning purposes, it is an ideal tool to assess the deltoid additionally. Future studies are warranted to determine whether preoperative fatty infiltration of the deltoid correlates with mid and long term functional outcomes when RSA is used acutely to manage a PHF.

LEVEL OF EVIDENCE

Level IV-consecutive case series.

Serum uric acid is not independently associated with plasma renin activity and plasma aldosterone in hypertensive adults

BACKGROUND AND AIMS

In experimental investigations conducted in rats, raising serum uric acid (SUA) levels resulted in the stimulation of intrarenal renin expression. Studies in humans exploring the association of SUA with plasma renin activity (PRA) yielded conflicting results. Moreover, little is known about the relationship of SUA with plasma aldosterone concentration (PAC). The study aimed to assess the relationship between SUA levels, PRA, and PAC and the influence of age, gender, body mass index (BMI), and hyperuricemia on these relationships in subjects with essential hypertension (EH).

METHODS AND RESULTS

We enrolled 372 hypertensive patients (mean age 45 ± 12 years, men 67%) with uncomplicated EH that was not pharmacologically treated. The study population was divided in tertiles according to SUA levels. While PRA did not differ significantly across the three tertiles, PAC was higher in subjects belonging to the uppermost tertile of SUA than those in the lower ones (p = 0.0429); however, this difference lost statistical significance after adjustment for age, sex, BMI, and serum creatinine. Univariate correlation analyses showed significant associations of SUA with PRA (r = 0.137; p = 0.008) and PAC (r = 0.179; p < 0.001). However, these relationships were not significant after correcting for confounding factors in multiple linear regression analyses. We did not observe statistically significant effect modification by gender, age, BMI, and hyperuricemia.

CONCLUSION

SUA levels are weakly associated with PRA and PAC in adults with untreated EH. These relationships were lost after adjustment for age, sex, BMI, and serum creatinine.

[First results with a resorbable MgYREZr compression screw in unstable scaphoid fractures show extensive bone cysts]

Osteosynthesis with headless compression screws is an established treatment option for unstable scaphoid fractures. Common implants are made of titanium alloy or steel and usually remain in place. Due to implant density and ferromagnetic properties, artefacts are common in postoperative imaging procedures, e.g. MRI. Now resorbable implants made of magnesium alloy (MgYREZr) have become available. They have biomechanical properties equivalent to human bone and may be used as an alternative to the nonresorbable screw systems.5 patients with acute scaphoid fractures were treated with a double-threaded screw made of MgYREZr. The fractures included three type A2 fractures, one type B2 fracture, and one type B3 fracture. All patients underwent clinical and radiological follow-up postoperatively, 6 weeks, 3 and 6 months and 1 year after surgery. ROM, gross grip strength and pain (VAS) were documented. The Modified Mayo Wrist Score was used. Standard X-rays of the wrist were taken preoperatively and at all follow-up visits. A CT scan was performed at least before and three months after surgery. In all X-rays malunion, resorption of the implant, implant loosening, cysts and bone healing (bridging trabecular structures) were described.All patients had a very good wrist score (95-100 points) after one year. There were no clinical complications. However, the X-rays revealed extensive resorption cysts in 3 out of the 5 patients. It was only after 6 months that the fractures were consolidated enough to allow physical work. Due to this considerable osteolysis, we did not include any further patients. Due to the observed extensive bone cysts and the long time period for bone healing, MgYREZr compression screws are currently not recommended for clinical use in scaphoid fractures. Further fundamental research is necessary.

Thermoablation of Bone Tumors

The aim of this article is to review the significance of percutaneous thermal ablation in the treatment of bone tumors. We describe available ablation techniques as well as advantages and disadvantages in specific settings. In detail, radiofrequency ablation (RFA), microwave ablation (MWA), laser ablation, high intensity focused ultrasound (HIFU) and cryoablation are presented. In the second part of this review curative and palliative indications for the treatment of benign and malignant bone tumors are discussed. This includes especially RFA, laser or cryoablation for the treatment of osteoid osteoma, as well as the palliative treatment of painful bone metastases, for example, by means of MWA or MR-guided HIFU.

KEY POINTS

• The various thermoablative techniques demonstrate specific advantages and disadvantages.• Radiofrequency ablation is the evidence-based method of choice for treating osteoid osteoma.• Laser ablation is primarily suited for the treatment of small lesions of the hands and feet.• The intrinsically analgesic effect of cryoablation is advantageous when treating painful lesions.• Palliative treatment of painful bone metastases can for example be performed using MWA or MR-guided HIFU, by itself or combined with cementoplasty. Citation Format: • Ringe KI, Panzica M, von Falck C. Thermoablation of Bone Tumors. Fortschr Röntgenstr 2016; 188: 539 - 550.

Soft Tissue Coverage of the Lower Limb following Oncological Surgery

The treatment of lower limb tumors has been shifted by advancements in adjuvant treatment protocols and microsurgical reconstruction from limb amputation to limb salvage. Standard approaches include oncological surgery by a multidisciplinary team in terms of limb sparing followed by soft tissue reconstruction and adjuvant therapy when indicated. For the development of a comprehensive surgical plan, the identity of the tumor should first be determined by histology after biopsy. Then the surgical goal and comprehensive treatment concept should be developed by a multidisciplinary tumor board and combined with soft tissue reconstruction. In this article, plastic surgical reconstruction options for soft coverage of the lower extremity following oncological surgery will be described along with the five clinical cases.

Biomechanical comparison of two surgical techniques for press-fit reconstruction of the posterolateral complex of the knee

BACKGROUND

To date, various surgical techniques to treat posterolateral knee instability have been described. Recent studies recommended an anatomical and isometric reconstruction of the posterolateral corner addressing the key structures, such as lateral collateral ligament (LCL), popliteus tendon (POP) and popliteofibular ligament (PFL). Two clinical established autologous respective local reconstruction methods of the posterolateral complex were tested for knot-bone cylinder press-fit fixation to assess efficacy of each reconstruction technique in comparison to the intact knee.

NULL HYPOTHESIS

The knot-bone cylinder press-fit fixation for both anatomic and isometric reconstruction techniques of the posterolateral complex shows equal biomechanical stability as the intact posterolateral knee structures.

STUDY DESIGN

This was a controlled laboratory study.

METHODS

Two surgical techniques (Larson: fibula-based semitendinosus autograft for LCL and PFL reconstruction/Kawano: biceps femoris and iliotibial tract autograft for LCL, PFL and POP reconstruction) with press-fit fixation were used for restoration of posterolateral knee stability. Seven cadaveric knees (66 ± 3.4 years) were tested under three conditions: intact knee, sectioned state and reconstructed knee for each surgical technique. Biomechanical stress tests were performed for every state at 30° and 90° knee flexion for anterior-posterior translation (60 N), internal-external and varus-valgus rotation (5 Nm) at 0°, 30° and 90° using a kinemator (Kuka robot).

RESULTS

At 30° and 90° knee flexion, no significant differences between the four knee states were registered for anterior-posterior translation loading. Internal-external and varus-valgus rotational loading showed significantly higher instability for the sectioned state than for the intact or reconstructed posterolateral structures (p < 0.05). There were no significant differences between the intact and reconstructed knee states for internal-external rotation, varus-valgus rotation and anterior-posterior translation at any flexion angles (p > 0.05). Comparing both reconstruction techniques, significant higher varus-/valgus stability was registered for the fibula-based Larson technique at 90° knee flexion (p < 0.05).

CONCLUSIONS

Both PLC reconstructions showed equal biomechanical stability as the intact posterolateral knee structures when using knot-bone cylinder press-fit fixation. We registered restoration of the rotational and varus-valgus stability with both surgical techniques. The anterior-posterior translational stability was not influenced significantly. The Larson technique showed significant higher varus/valgus stability in 90° flexion. The latter is easier to perform and takes half the preparation time, but needs grafting of the semitendinosus tendon. The Kawano reconstruction technique is an interesting alternative in cases of missing autografts.

Nail-medullary canal ratio affects mechanical axis deviation during femoral lengthening with an intramedullary distractor

INTRODUCTION

Callus distraction of the femur using an intramedullary distractor has several advantages over the use of external fixators. However, difficulty in controlling the mechanical axis during lengthening may cause deformities and knee osteoarthritis. Purpose of the study is to answer the following questions: (1) is lengthening with an intramedullary device associated with a medial or lateral shift of the mechanical axis? (2) Which factors are associated with varisation/valgisation of the mechanical axis during lengthening?

MATERIALS AND METHODS

We analysed pre-treatment and post-treatment radiographs from 20 patients who underwent unilateral femoral-lengthening procedures using intramedullary distractors. Patients with acute correction of pre-existing deformities or combined ipsilateral femoral and tibial lengthening were excluded. Mechanical axis deviations, osteotomy level, and nail-medullary canal ratio were recorded.

RESULTS

Compared to the preoperative axis, the mechanical axis shifted medially in 7 patients (varisation group) and laterally in 13 patients (valgisation group). The groups did not significantly differ regarding preoperative leg length discrepancy (LLD), mechanical axis alignment, LLD-cause and implants used. The nail-medullary canal ratio significantly differed between groups (p<0.001), being <85% in the varisation group and >85% in the valgisation group. The distance between the lesser trochanter and the osteotomy site was significantly longer in the valgisation group (58.9±16.3mm, middle third of the femur) compared to the varisation group (40.6±11.4mm, proximal third of the femur; p=0.02).

CONCLUSION

The nail-medullary canal ratio should be considered during preoperative planning. To avoid a varisation effect-for example, in cases with pre-existing varus alignment-it would be advisable to perform an osteotomy at the middle third of the femur with implantation of a nail that fully covers the medullary canal at the osteotomy site.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

[New therapy approaches for giant cell tumors]

BACKGROUND

Giant cell bone tumors (GCT) are benign but partially locally aggressive osteolytic tumors which typically occur around the knee joint in the epiphysis and metaphysis of long bones after maturation of the skeleton is completed. Due to the locally aggressive growth behavior with destruction of the bone structure, the rare possibility of pulmonary metastases in recurrent cases and a very rare possibility of malignancy, GCTs were previously also described as semimalignant bone tumors.

THERAPY

The established therapy of these tumors at the typical locations consists of intralesional curettage, extension of resection margins using a high speed trephine and defect reconstruction with bone cement. The local recurrence rate is high (10-40 %) and lowest after using thermal extension of resection margins with a high speed trephine and defect reconstruction with bone cement. For uncommon localizations, such as the spinal column and the sacrum as well as in cases of recurrence, surgical treatment is more complicated.

HISTOLOGY

Histologically, GCTs consist of osteoclastic giant and oval-shaped stromal cells which show a high expression of receptor activator of nuclear factor-κB ligand (RANKL) and decisively contribute to the osteolytic activity of the tumor. Novel pharmaceutical therapy approaches with human monoclonal RANKL antibodies interfere in this osteodestructive process in an inhibitory manner and can represent alternative treatment options just as the osteosupportive therapy with bisphosphonates.

CONCLUSION

After unsatisfactory attempts at surgical treatment of GCT patients, the new treatment option with denosumab is a promising alternative due to its effect as a monoclonal RANKL inhibitor.

[Biopsy and approach routes for bone tumors. Where and how much is sufficient?]

Although biopsies are a key step in the diagnosis of bone tumors, they are often still referred to as a minor intervention which can be carried out by any surgeon as an outpatient procedure or quickly carried out between other more important tasks. A biopsy should, however, be regarded as the final part of the diagnostic procedure preceded by careful evaluation of the clinical course and analysis of the required imaging studies. Although the biopsy procedure seems technically simple to perform, an incorrectly performed biopsy can become an obstacle to correct tissue analysis (sampling error) and adequate tumor resection and may reduce the patient's chances of survival. The principles by which an adequate and safe biopsy of bone tumors should be planned and executed are reviewed and the surgical approaches to different anatomical locations are presented.

Vertebral fractures in motor vehicle accidents - a medical and technical analysis of 33,015 injured front-seat occupants

Spinal injuries pose a considerable risk to life and quality of life. In spite of improvements in active and passive safety of motor vehicles, car accidents are regarded as a major cause for vertebral fractures. The purpose of this study was to evaluate the current incidence of vertebral fractures among front-seat occupants in motor vehicle accidents, and to identify specific risk factors for sustaining vertebral fractures in motor vehicle accidents. Data from an accident research unit were accessed to collect collision details, preclinical data, and clinical data. We included all data on front-seat occupants. Hospital records were retrieved, and radiological images were evaluated. We analysed 33,015 front-seat occupants involved in motor vehicle accidents over a 24-year period. We identified 126 subjects (0.38%) with cervical spine fractures, 78 (0.24%) with thoracic fractures, and 99 (0.30%) with lumbar fractures. The mean relative collision speeds were 48, 39, and 40 kph in subjects with cervical, thoracic, and lumbar spine fractures, respectively, while it was 17.3 kph in the whole cohort. Contrary to the overall cohort, these patients typically sustained multiple hits rather than simple front collisions. Occupants with vertebral fractures frequently showed numerous concomitant injuries; for example, additional vertebral fractures. The incidence of vertebral fractures corresponded with collision speed. Safety belts were highly effective in the prevention of vertebral fractures. Apart from high speed, complex injury mechanisms as multiple collisions or rollovers were associated with vertebral fractures. Additional preventive measures should focus on these collision mechanisms.

[The critical incident reporting system as an instrument of risk management for better patient safety]

The probability that an inpatient will be harmed by a medical procedure is at least 3% of all patients. As a consequence, hospital risk management has become a central management task in the health care sector. The critical incident reporting system (CIRS) as a voluntary instrument for reporting (near) incidents plays a key role in the implementation of a risk management system. The goal of the CIRS is to register system errors without assigning guilt or meting out punishment and at the same time increasing the number of voluntary reports.

Rotational alignment in total knee arthroplasty: intraoperative inter- and intraobserver reliability of Whiteside's line

INTRODUCTION

Proper rotational alignment is a critical step of total knee arthroplasty. For intraoperative determination of femoral rotation, Whiteside suggests a perpendicular line to the axis of the center of the trochlea and the intercondylar notch (Whiteside's line).

METHOD

In a prospective clinical study, the intraoperative position of Whiteside's line was measured in 30 patients with the help of a navigation system.

RESULTS

Whiteside's line was 2.1° ± 1.5° externally rotated compared to a navigation based computer calculated preliminary AP axis of the femur. The intraobserver-reliability after 3 repeated measurements each was 1.6° for the senior surgeon and 1.4° for the junior surgeon (p = 0.598, p = 0.968). The interobserver reliability between the measurements by the senior and junior surgeon was 1.4° (p = 0.547).

CONCLUSION

Navigated intraoperative measurements of Whiteside's line showed a high inter- and intraobserver reliability. Considering the variability between Whiteside's line and the transepicondylar axis, intraoperative assessment of both the methods is recommended.

SAXS study on myoglobin embedded in amorphous saccharide matrices

We report on Small Angle X-ray Scattering (SAXS) measurements performed on samples of carboxy-myoglobin and met-myoglobin embedded in low hydrated matrices of four different saccharides (trehalose, sucrose, maltose and lactose). Results confirm the already reported occurrence of inhomogeneities, which are not peculiar of trehalose samples, but appear also in maltose and lactose, and in some cases also sucrose, being dependent on the sample hydration and on the presence of sodium dithionite. This behaviour confirms our previous interpretation about the nature of the inhomogeneities, and prompt it as a possible general behaviour for highly concentrated sugar matrices.

Accuracy of digital preoperative planning for total knee arthroplasty

INTRODUCTION

The accuracy of preoperative planning of the size of total knee arthroplasty (TKA) in literature is only 50%. A problem of conventional radiographic planning with prosthesis templates is varying enlargement of the radiographs. Digital planning and analysis of lower leg geometry revealed improved reliability compared to conventional techniques. The aim of the study was to evaluate the accuracy of digital planning of TKA with special planning software and calibrated radiographs and its interobserver reliability.

METHODS

In a prospective study the sizes of 30 TKA were planned with special software by a senior and a junior surgeon independently. For calibration a 30 mm reference ball on the radiographs was used. The planning was compared with the intraoperative chosen size of the TKA.

RESULTS

The correlation of the planned femoral component with the chosen size was 87% for the senior and 77% for the junior surgeon. The planning of the tibial component revealed a correlation for the senior surgeon in 90% and for the junior surgeon in 87%. Both component was planned correctly in 77% by the senior and in 63% by the junior surgeon. In 50% the planning of both surgeons matched completely the used prosthesis sizes. The linear κ coefficient of Cohen revealed a good agreement (0.65) and a high interobserver reliability.

DISCUSSION

Planning TKA with special planning software with digital, calibrated radiographs is more accurate compared to previous conventional planning. The senior surgeons planning of both component sizes matched in 77% the correct size. Clinical experience improves the accuracy of preoperative planning.

Long-term outcome after joint reconstruction or medial resection arthroplasty for anterior SCJ instability

INTRODUCTION

In the present study, the long-term results of 11 patients with anterior sternoclavicular joint (SCJ) instability are reported. All included patients had an anterior SCJ instability and due to delayed diagnosis, operative treatment was not done immediately.

METHOD

The patients had a mean age of 29.2 years (range 16-63 years). One patient sustained concomitant injuries. Six patients had resection arthroplasty. Five patients had reconstruction of the SCJ with transosseous tension band PDS fixation or ligament reconstruction with additional wire cerclage. The results of treatment were evaluated after a mean follow-up period of 9.9 years (range 1-27 years) using the ASES, DASH and power-, age and gender adjusted Constant-Murley Score.

RESULTS

In general, the mean values of the different scores (ASES 79.8; DASH 11.8; Constant-Murley 81%) demonstrated good outcome. The outcome evaluation of the patients who had SCJ reconstruction did not differ significantly from the patients who had medial resection arthroplasty. The rate of postoperative pain or instability was low using visual analog scale and did not differ significantly between the groups. The outcome results of the reconstruction group were equal to the results of the resection group when SCJ-reconstruction was performed soon after SCJ injury. One patient in the resection group (6 patients) demonstrated poor results due to continued instability of the remaining clavicle.

CONCLUSION

We concluded that patient selection and a specific clinical indication for operative treatment are crucial. Resection of the medial clavicle results in good functional outcome when the costoclavicular ligament is preserved or reconstructed.

Modified rerouting procedure for failed peroneal tendon dislocation surgery

Recurrent dislocation of the peroneal tendons following operative treatment is relatively uncommon, but can be difficult to treat. We asked whether subligamental transposition of the peroneus brevis tendon, fibular grooving, and reattachment of the superior peroneal retinaculum for failed peroneal tendon dislocation surgery would achieve a stable fixation of the peroneal tendons and whether there would be restrictions of ROM or instability of the hindfoot. We reviewed six female patients (mean age, 24.5 years) with general laxity of joints preoperatively and at 6 weeks and 3, 6, and 12 months postoperatively. Within 1 year postoperatively no recurrence was found. In two ankles the extension was restricted 5 degrees to 10 degrees . In another pronation and supination was restricted 5 degrees each. Stability of the ankle increased in four patients and stayed unchanged in two. AOFAS score increased from a mean value of 36 +/- 20.6 preoperatively to 90 +/- 7 postoperatively at 1 year. We conclude transposition of the peroneus brevis tendon is a reasonable treatment for failed peroneal tendon dislocation surgery.

LEVEL OF EVIDENCE

Level IV, therapeutic study (prospective case series). See Guidelines for Authors for a complete description of levels of evidence.

[Injury situation of novice drivers in road traffic--a medical and technical analysis]

AIM

Novice drivers are at high risk for crash involvement. We performed an analysis of causations, injury patterns and distributions of novice drivers in cars and on motorcycles in road traffic as a basis for proper measurements.

METHOD

Data of accident and hospital records of novice drivers (licence < 2 years) were analysed focusing on the following parameters: injury type, localisation and mechanism, abbreviated injury scale (AIS), maximum AIS (MAIS), delta-v, collision speed and other technical parameters and compared with those of experienced drivers.

RESULTS

In 18 352 accidents in the area of Hannover (years 1985-2004), 2602 novice drivers and 18 214 experienced drivers were recorded as having an accident. Novice car drivers were more often and more severely injured whereas on motorcycles the experienced drivers were at higher risk. Novice drivers of both groups sustained more often extremity injuries. 4.5 % of the novice car drivers were not restrained by seatbelts as compared to 3.7 % of the experienced drivers and 6.1 % of the novice motorcycle drivers did not wear a proper helmet (versus 6.5 %). Severe injuries were sustained in 20 % at collision speeds below 30 km/h and in 80 % at collision speeds above 50 km/h. Novice car drivers drove significantly older cars. The risk profile of novice drivers is similar to that of drivers older than 65.

CONCLUSION

Structural protection and special lectures like skidding courses could be proper measurements next to harder punishment of violations.

[Rearthrodesis of the radiolunate joint]

Since 1983, radiolunate arthrodesis has been the gold standard for stabilising the rheumatic wrist. Rearthrodesis of the radiolunate joint has not yet been described. In a prospective study on five radiolunate rearthrodeses with a dorsal mini titanium plate and oblique screw, bone healing was achieved in four. Fatigue fracture of the plate occurred in one case of delayed bone healing. After another rearthrodesis using the same technique, bone healing was achieved. Complete fusion of the wrist can be avoided after failed radiolunate fusion using the described operative technique for rearthrodesis of the radiolunate joint. Preserving some wrist mobility is of high value for these multimorbid patients.

[Hannover-Polytrauma-Longterm-Study HPLS]

From the period of September 2000 to March 2006 Hannover Reinsurance and the Department of Traumatology of the Hanover Medical School conducted a retrospective observational study of the long-term outcome of patients after polytrauma. The follow-up period was on average 17 +/- 5 years. The goal of the study was to determine the social, financial, medical and psychological long-term outcome after a severe accident. Of the 1560 enrolled patients 519 patients died in the observed period, 397 patients were followed up but could not be examined, 637 patients (female n = 158, male n = 479) were examined and answered detailed questionnaires concerning their social, financial medical and psychological situation. 6 patients did not fullfil the input criteria and one patient had two polytraumata. The average age at the time of accident was 26.5 years (+/- 12.3).

RESULTS

Financial losses were observed in 41.1% of all males and 44.4% of females. 21.7% of all male (female 18.4%) had no financial protection at all. Due to the accident 30.1% of all men were unemployed and 19.8% permanently disabled (women 27.4% and 27.6% respectively). Psychological treatment almost doubled after discharge from rehabilitation centres. Even 20 years after the accident extra-mortality was substantially increased by 79%.

CONCLUSION

Ten to twenty years after polytrauma significant financial, social and medical impairments are still present.

Evaluation and outcome of patients after polytrauma--can patients be recruited for long-term follow-up?

INTRODUCTION

There is limited information available about the long-term follow-up of polytrauma patients. In this study, the social and medical sequelae of trauma were reinvestigated at 10 years after the injury.

METHODS

Patients were selected out of a population of polytraumatised patients treated at Hannover Medical School between 1973 and 1990.

INCLUSION CRITERIA

multiple injuries treated at one institution, age between 3 and 60 years of age at the time of injury. Patients were recruited by gathering their residences from the charts. If patients had moved, up to three different registration offices were contacted by mail. The patient was contacted by mail (maximum three times) and by telephone. A patient was documented as lost to follow-up if none of these attempts was successful, or if he did not fulfil three subsequent appointments. All patients were examined by a physician, using a patient questionnaire and a standardized physical exam.

RESULTS

Six hundred thirty-seven patients (67.8% of the potential enrollees) were evaluated on an outpatient basis by a trauma surgeon using a self-administered patient questionnaire and a standardized physical exam. In these, the average follow-up was 17.5 (range 10-28) years; the average Injury Severity Score (ISS) was 20.7 (range 4-54). Head injuries were the third most frequent injuries, but represented the most frequent cause of permanent disability (40%). The overall rehabilitation status graded by the patients was very good in 14.1%, good in 33.0%, satisfactory in 29.3%, sufficient in 16.0% and poor or insufficient in 7.5%.

CONCLUSIONS

This study suggests that a high percentage of patients can be recruited for follow-up even after 10 years post trauma with the use of a meticulous reinvitation strategy. Head injuries accounted for the most frequent cause of disability, suggesting that more research should be provided to minimise the degree of injury and improve the outcome for head injured patients. Subjective grading of the outcome was better than expected in patients who had regained complete social rehabilitation.

Influence of workers’ compensation eligibility upon functional recovery 10 to 28 years after polytrauma

BACKGROUND

Previous studies have shown that work-related injuries are often associated with inferior outcomes. The aim of the current study was to compare the long-term functional outcome after polytrauma between work-related and non-work-related injuries at a minimum follow-up of 10 years.

METHODS

Six hundred thirty-seven polytrauma patients were evaluated using a patient questionnaire and a physical examination. The average follow-up was 17.5 years (range 10-28 years); the average Injury Severity Score (ISS) was 20.7 (range 4 to 54).

RESULTS

A multivariate analysis, with adjustments for age, sex, injury severity, and injury pattern, demonstrated that work-related injuries resulted in significantly inferior outcomes measured by the Hannove Score for Polytrauma Outcome (HASPOC), 12-Item Short-Form Health Survey (SF-12), requirement for medical aids and devices, length of rehabilitation, and retirement status (P < .05).

CONCLUSIONS

Polytrauma patients receiving workers' compensation achieve significantly inferior long-term outcomes than other patients. The obtained results demonstrate that psychosocial variables such as insurance status have a significant impact on the functional recovery following polytrauma.

The impact of injuries below the knee joint on the long-term functional outcome following polytrauma

Previous studies have suggested that the lower-extremities are among the most frequently injured body regions in polytrauma patients and have a major impact on the functional recovery following polytrauma. In particular, injuries to the distal part of the lower-extremity appear to be associated with a poor functional outcome. Therefore, the goal of this study was to evaluate the impact of injuries below the knee joint on the long-term functional outcome following polytrauma. Three hundred eighty-nine polytrauma patients with associated lower-extremity fractures and a minimum follow-up of 10 years were included in this study. All patients were examined by a doctor, using a patient questionnaire and a standardised physical examination. Significantly, inferior outcomes were seen in patients with fractures below the knee joint as measured by the modified Karlström-Olerud score, Lysholm score, range of motion, weight bearing status, Hannover score for polytrauma outcome (HASPOC), SF-12, Tegner activity score, and inability to work (P < 0.05). Fractures below the knee joint have a significant impact on the functional recovery following polytrauma. We suggest that delayed treatment, thin soft tissue envelope below the knee joint, high-energy trauma, unfavorable blood supply, and complex fracture patterns contribute to these unfavorable outcomes.

Combination of femoral fracture treatment and corrective osteotomy in a child with osteogenesis imperfecta

The main feature of osteogenesis imperfecta is an excessive fragility and deformability of the bones owing to reduced mass and bone quality. This leads to angular deformity and frequent fractures. These fractures usually heal rapidly, and conservative treatment is the norm. In displaced and unstable fractures, elastic intramedullary nailing is a treatment option. We report a case of a 3-year-old child with osteogenesis imperfecta type I who suffered an undisplaced femoral shaft fracture in the presence of a preexisting 32 degrees femoral antecurvation. This deformity greatly increases the risk of a refracture due to the pathological induction of stress risers. Therefore, fracture treatment by unreamed elastic intramedullary nailing was combined with simultaneous correction osteotomy, resulting in anatomic alignment and uncomplicated fracture healing. The single-stage surgical stabilization performed allowed rapid mobilization along with a decreased likelihood of refracture.

Standardized outcome evaluation after blunt multiple injuries by scoring systems: a clinical follow-up investigation 2 years after injury

OBJECTIVE

The objective of this study was to evaluate the state of rehabilitation in patients with blunt multiple injuries 2 years after their initial injuries, using several standardized scales and a recently described comprehensive scoring system, by means of a prospective clinical multicenter study.

METHODS

Two years after the initial injury, patients with blunt multiple injuries (Injury Severity Score > or = 16) underwent a clinical follow-up in 5 German Level I trauma centers. The reassessment included a complete head-to-toe examination of the musculoskeletal system and a neurologic examination. The following patient-assessed health status scores were used to determine the quality of life: Short-Form 12, Functional Independence Measurement, and Musculoskeletal Function Assessment. Moreover, a comprehensive scoring system developed in our department (Hannover Score for Polytrauma Outcome [HASPOC]) was used that includes provider-report (physician's examination) and self-report (score systems) criteria.

RESULTS

Two hundred fifty-four of 312 patients who had been injured between January 1995 and July 1996 were reexamined between January 1, 1997, and July 1, 1998. Among the remaining 58 patients, 9 had died by the time of follow-up, and 49 patients had not accepted the invitation. The mean age of those patients who underwent reexamination was 36 +/- 13 years, the mean Injury Severity Score was 24 +/- 6, and the mean initial Glasgow Coma Scale score was 11 +/- 4 (Abbreviated Injury Scale (AIS) head score of 3.3 +/- 1.1; AIS face, 1.4 +/- 0.1; AIS chest, 3.0 +/- 0.8; AIS abdomen, 1.7 +/- 0.6; and AIS extremities, 3.4 +/- 0.8). The general outcome (Short-Form 12) was as follows: grade I, 9%; grade II, 25%; grade III, 29%; grade IV, 25%; grade V, 6%; and grade VI, 6%. The outcome of the injured extremity demonstrated moderate or severe restrictions according to the Musculoskeletal Function Assessment in 41% of injuries of the lower extremity and in 16% of injuries of the upper extremity. Among patients with injuries to the lower extremity, 52% experienced pain or impaired ability to walk related to an injury of the foot or ankle, 31% indicated pain after a knee or thigh injury, and 27% indicated pain after a femoral or hip injury. The most severe deficits in the range of motion occurred in the foot and the ankle region (13.4% deficit of range of motion < 20% of normal range, p < 0.05 to other injuries). The results of the outcome obtained by self-report correlated with the clinical examination when a scoring system was used that was described recently, the HASPOC.

CONCLUSION

In a standardized multicenter reexamination of patients with blunt multiple injuries, the general outcome was usually fair or good. Both the complaints and the objective results of specific extremity areas demonstrated that most limitations were because of injuries below the knee. These results were adequately reflected by a comprehensive scoring system, combining self-report and provider report (HASPOC).

Diagnostic benefit of echocontrast enhancement for the insufficient transtemporal bone window

Echocontrast agents (ECA) are known to improve transcranial color-coded duplex (TCCD) imaging, but its diagnostic benefit in the routine clinical setting has not clearly been defined. The authors investigated the diagnostic benefit of ECA application in 54 patients with insufficient transtemporal bone window, consecutively referred to their ultrasound laboratory. According to the precontrast imaging quality, patients were assigned to three categories: A, no intracranial structures or vessel segments visible on B-mode imaging and TCCD (n = 5); and intracranial structures visible on B-mode imaging and vessel segments less than 5 mm in length (B, n = 21), or larger than 5 mm in length (C, n = 28) visible on TCCD. The effect of the echocontrast enhancement was assessed with respect to signal enhancement, imaging quality, and diagnostic confidence. In 49 out of 54 patients (91%), a significant improvement of the imaging quality was noted, enabling 43 (80%) neurovascular diagnoses of sufficient diagnostic confidence. The diagnostic ECA effect was strongly dependent on the precontrast imaging quality: upon echoenhancement, a satisfactory image quality was obtained in none of the patients of category A, as opposed to 16 (76%) and 27 (96%) patients of categories B and C, respectively. In summary, in 80% of our consecutive patient series with insufficient transtemporal bone window, application of ECA allowed for a conclusive TCCD study. Properties of the transtemporal precontrast scans are strongly predictive of the diagnostic benefit and should be taken into the decisive consideration.

[Clinical significance of echocontrast enchancement in neurovascular diagnosis. Review of experience following a year of use]

AIM OF THE STUDY

To evaluate the potential and limitations of echocontrast enhancement using Levovist in a non selected consecutive cohort of neurological patients with insufficient native ultrasound investigations.

METHODS

In 91 patients an indication for echocontrast application was seen after an insufficient extracranial (n = 17), transtemporal (n = 54), and transforaminal (n = 20) Doppler- und color-coded Duplex sonography. Levovist was injected at a concentration of 400 mg/ml and 200-400 mg/ml for the transcranial and extracranial approach, respectively. The effect of the echocontrast enhancement was assessed semiquantitatively with respect to signal enhancement, imaging quality, and diagnostic confidence.

RESULTS

In a total of 83 patients (91%) the signal enhancement led to a moderate to high imaging quality allowing to reach 67 definite neurovascular diagnoses (74%). In subgroup analysis, the amount of sufficiently confident examinations was significantly higher for the transtemporal and transforaminal (both 80%) than for the extracranial approach (47%). The latter was mostly due to artificial signals derived from adjacent neck vessels.

CONCLUSION

Levovist constitutes a safe and highly effective diagnostic tool especially for the transtemporal and transforaminal neurosonographical imaging. By means of a differentiated application of echocontrast agents, its cost-effectiveness can be increased and the need for other potential invasive and expansive neuroimaging methods can be further reduced.

TA1, a highly conserved oncofetal complementary DNA from rat hepatoma, encodes an integral membrane protein associated with liver development, carcinogenesis, and cell activation

Hepatocellular carcinoma is characterized by changes in gene expression associated with cell growth and differentiation. Cell surface antigenic changes have also been described based on differential antibody reactivity between normal and neoplastic liver. We obtained a novel tumor-associated cDNA designated TA1 on the basis of its differential expression between hepatoma cells and normal liver. Sequence analysis predicted a 723-base pair open reading frame with the deduced amino acid sequence encoding an integral membrane protein containing multiple hydrophobic transmembrane domains. Database searches revealed TA1 as the likely rat homologue of E16, a recently cloned human cDNA associated with lymphocyte activation. Although noncoding sequences diverged significantly, the 95% conservation of the predicted proteins between species strongly suggests an important, although as yet undefined, function in normal cells. TA1 transcripts were detected in normal adult rat tissues including testes, brain, ovary, spleen, mammary gland, and uterus with the highest steady-state expression in placenta. Although no expression was detected in normal liver, all rat hepatomas examined expressed an abundant 3.2-kilobase transcript. TA1 expression was closely associated with progression in this tumor model and suggests this molecule, originally linked to cell activation, also plays a role in the malignant phenotype.

A Fischer rat substrain deficient in dipeptidyl peptidase IV activity makes normal steady-state RNA levels and an altered protein. Use as a liver-cell transplantation model

Dipeptidyl peptidase IV (DPPIV) is a serine exoproteinase expressed at high levels in epithelial cells of kidney, liver and small intestine. Recently Watanabe, Kohima & Fujimoto [(1987) Experientia 43, 400-401] and Gossrau et al. [(1990) Histochem. J. 22, 172-173] reported that Fischer 344 rats are deficient in this enzyme. We have examined DPPIV expression in Fischer 344 rats available from U.S. and German suppliers and find that livers of the U.S. Fischer rats, in contrast with their German counterparts, express active DPPIV (D+). Northern analysis of liver RNA showed comparable levels of 3.4 kb and 5.6 kb DPPIV transcripts in both D+ rats from the U.S. and German (D-) rats. Monoclonal antibody (MAb) 236.3 to DPPIV immunoprecipitated at 150 kDa enzymically active (105 kDa, denatured) protein from surface-labelled D+ hepatocytes and reacted with canalicular and sinusoidal membranes (as shown by immunofluorescence microscopy). MAb 236.3 failed to immunoprecipitate a labelled peptide from D- cell extract or to stain D- liver sections. Polyclonal antibody (PAb) specific for DPPIV immunoprecipitated an enzymically active peptide from D+ hepatocyte extracts and a smaller, inactive peptide from D- hepatocyte extracts. Peptide maps of DPPIV immunoprecipitated from D+ extracts with MAb 236.3 and PAb were identical, but differed from that of the D- hepatocyte component recognized by PAb. The molecular basis of the DPPIV deficiency in the D- rats thus appears to be the translation of an enzymically inactive protein missing the epitope recognized by MAb 236.3. We have exploited these D- rats as hosts for syngeneic transplantation of liver cells from D+ Fischer rats. DPPIV expression is stable in the transplanted cells and allows them to be readily distinguished from the surrounding D- tissue.

Transforming growth factor beta mRNA increases during liver regeneration: a possible paracrine mechanism of growth regulation

Transforming growth factor beta (TGF-beta) is a growth factor with multiple biological properties including stimulation and inhibition of cell proliferation. To determine whether TGF-beta is involved in hepatocyte growth responses in vivo, we measured the levels of TGF-beta mRNA in normal liver and during liver regeneration after partial hepatectomy in rats. TGF-beta mRNA increases in the regenerating liver and reaches a peak (about 8 times higher than basal levels) after the major wave of hepatocyte cell division and mitosis have taken place and after the peak expression of the ras protooncogenes. Although hepatocytes from normal and regenerating liver respond to TGF-beta, they do not synthesize TGF-beta mRNA. Instead, the message is present in liver nonparenchymal cells and is particularly abundant in cell fractions enriched for endothelial cells. TGF-beta inhibits epidermal growth factor-induced DNA synthesis in vitro in hepatocytes from normal or regenerating liver, although the dose-response curves vary according to the culture medium used. We conclude that TGF-beta may function as the effector of an inhibitory paracrine loop that is activated during liver regeneration, perhaps to prevent uncontrolled hepatocyte proliferation.

Methylation of the alphafetoprotein gene in cell populations isolated from rat livers during carcinogenesis

We examined the methylation pattern and organization of the AFP gene in whole livers and in isolated cell populations purified from livers of rats fed a carcinogenic diet which interferes with DNA methylation. Using restriction endonuclease digestion, we find no differences in methylation pattern and overall organization of the AFP gene in oval cells (AFP-producers) and hepatocytes (non-producers) isolated at the early stages of carcinogenesis. Our studies indicate that in cell populations which produce AFP as well as in cells which are not active in AFP synthesis, the majority of the CCGG sites of the AFP gene are extensively methylated. In addition, we describe the existence of polymorphism in the AFP and albumin genes of Sprague-Dawley rats.

Cell lineages in liver carcinogenesis: possible clues from studies of the distribution of alpha-fetoprotein RNA sequences in cell populations isolated from normal, regenerating, and preneoplastic rat livers

We analyzed in isolated rat liver cell populations and in fetal and neoplastic livers the distribution of RNA sequences which hybridize with alpha-fetoprotein (AFP) complementary DNA clones. Parenchymal and nonparenchymal cell populations were isolated from normal, regenerating, preneoplastic, and bile duct-ligated rat livers. We found that oval cells, fetal liver, and a primary hepatocellular carcinoma contain the full length 2.3-kilobase AFP messenger RNA (mRNA); in normal adult rat liver, 2.3-kilobase AFP mRNA is found at low levels in an unidentified subpopulation of nonparenchymal cells but is not detected in hepatocytes; both parenchymal and nonparenchymal cells from normal or preneoplastic livers contain in variable proportion a smaller AFP RNA which hybridizes only with complementary DNA clones containing sequences located near the 5' end of the rat AFP gene; during liver regeneration induced by CCl4, elevation of the full length AFP mRNA occurs in nonparenchymal cells but seemingly not in hepatocytes. The results suggest that some cells in the nonparenchymal cell fraction of normal adult rat liver might retain the capacity to produce the 2.3-kilobase AFP mRNA found in large amounts in fetal livers, oval cells, and hepatic tumors. Although the nature of these cells remains to be determined, we suggest that such cells might be the source of the small amounts of AFP synthesized in normal rat liver and may constitute the proposed but as yet uncharacterized "facultative stem cell" compartment in rat liver.