Computed tomography osteoabsorptiometry is reliable for the determination of the subchondral bone mineralization distribution in the rabbit knee.

Rabbits are among the most frequently used animals in osteoarthritis research. It is meanwhile accepted that the subchondral bone plate (SBP) plays a key role in the development of osteoarthritis. The most suitable technique for analyzing subchondral bone mineralization is computed tomography osteoabsorptiometry (CT-OAM). Because CT-OAM has not yet been applied to smaller animals, the purpose of this study is to test the reliability of CT-OAM in the rabbit knee. Another important task in animal experiments is the intra- and interindividual difference of the measurement parameters. Our hypothesis is that there is no difference regarding both the position of the density maxima and the bone mineral density (BMD) of the SBP comparing right and left tibial plateaus of rabbits. For evaluating the reliability, a rabbit knee was examined by computed tomography 6 times at weekly intervals. The subchondral mineralization distribution was measured by means of CT-OAM. Positions of the density maxima and BMD of the SBP were determined in a standardized procedure. Furthermore, both parameters were evaluated in 6 female White New Zealand rabbits. Positions of density maxima and BMD in the SBP in left tibial plateaus were compared with right tibial plateaus. The relative coefficient of variation as a parameter for reproducibility was 1.6% for determining the position of the density maxima and 1.2% for measuring the BMD. The positions of density maxima and relative BMD between right and left tibial plateaus varied only about 2% intraindividually, whereas interindividual variance was about 10%. In conclusion, determination of the position of density maxima as well as BMD of the SBP by means of CT-OAM is reliable and reproducible in the rabbit knee. We recommend using the contralateral limb as control, because intraindividual accordance of the mineralization patterns and of the BMD of the SBP was higher than interindividual accordance.

An evaluation of the efficiency of the use of an anatomical third generation shoulder prosthesis in 102 patients.

PURPOSE OF THE STUDY: In this study a series of 102 cases was reviewed in which a so called third generation shoulder prosthesis had been used. There was an interest in evaluating the quality and efficiency of the outcome. MATERIAL AND METHODS: The patient population consisted of 32 men and 70 women. The mean age was 65.8 years. The mean postoperative follow-up time was 44.5 months. Indication for arthroplasty was all common degenerative and traumatic conditions of the shoulder. All patients were evaluated and analysed prospectively by a standardised protocol. The postoperative investigation consisted of a clinical examination and a radiographic analysis. We used the Constant and the Wülker Score. RESULTS: All patients had a significant improvement in shoulder function independent of the specific indication. The mean postoperative shoulder function attained 88% as measured by the Constant score. With regard to the different indications, the significant improvement was confirmed in each of the groups. Osteoarthritis reached the highest (91%) and rheumatoid arthritis the lowest value (71%). The results of total shoulder arthroplasties was better than in hemi-shoulder arthroplasties (93% versus 86%). CONCLUSIONS: In summary, it could be demonstrated that most indications for shoulder arthroplasty can be successfully treated by using a third generation implant. Total shoulders reach better results in a mid-term follow-up.

Coracoid tip position on frontal radiographs of the shoulder: a predictor of common shoulder pathologies?

The coracoacromial arch is a static anterior-superior stabilizer of the humeral head. Thus coracoacromial arch inclination, which varies depending on coracoid tip position, may be related to shoulder pathologies. Therefore, we retrospectively analysed coracoid tip positions in the true anterior posterior view of different shoulder pathologies: reference shoulders (n=27), shoulders with rotator cuff tear (supraspinatus tear n=29; subscapularis tear n=21) and shoulders with anterior glenohumeral instability (traumatic n=17; atraumatic n=14). In supraspinatus tear shoulders, the coracoid tip projected onto inferior glenoid half in 86% of cases (type I coracoid), extending more inferiorly compared with reference group (p=0.0002) or subscapularis tear shoulders (p<0.0001). In contrast, 78% of cases with subscapularis tear show the coracoid tip projected onto the superior glenoid half (type II coracoid). Atraumatic glenohumeral instabilities had a more superior coracoid tip position than traumatic instabilities (p=0.04), but no differences were observed on basis of coracoid type or in comparison with normal controls. We conclude that coracoid tip position is highly variable. Since type I coracoids are predominant in shoulders with supraspinatus tears and type II coracoids in shoulders with subscapularis tears, coracoid tip position may thus provide a simple diagnostic complement for a probable site of rotator cuff tears.

Fluorescent microsphere method is suitable for chronic bone blood flow measurement: a long-term study after meniscectomy in rabbits.

The fluorescent microsphere (FM) method is considered a reliable technique to determine regional bone blood flow (RBBF) in acute experiments. In this study, we verified the accuracy and validity of this technique for measurement of RBBF in a long-term experiment and examined RBBF after meniscectomy. Twenty-four anesthetized female New Zealand white rabbits (3 groups, each n = 8) received consecutive left ventricular injections of FM in defined time intervals after meniscectomy: group 1 from preoperation to 3 wk postoperation; group 2 from 3 to 7 wk postoperation; and group 3 from 7 to 11 wk postoperation. To test the precision of the FM method, two FM species were injected simultaneously at the first and last measurement. After the experiment, humeri, femora, tibiae, and reference organs (kidney, lung, brain) were removed and dissected according to standardized protocols. Fluorescence was determined in each reference blood and tissue sample, and blood flow values were calculated. Blood flow in kidney, lung, and brain revealed no significant difference between right and left side and remained unchanged during the observation period, thus excluding errors due to shunting and dislodging of spheres in our experiments. Comparison of relative bone blood flow values obtained by simultaneously injected FM showed an excellent correlation at the first and last injection, indicating valid RBBF measurements in long-term experiments. We found a significant increase in RBBF 3 wk after meniscectomy in the right tibial condyles compared with the nonoperated left side. Similar changes were found in the femoral condyles. RBBF in other regions of tibia, femur, and humerus revealed no significant differences between right- and left-sided bone samples of the same region. Our results demonstrate that the FM method is valid for measuring RBBF in long-term experiments. In addition, we were able to demonstrate that meniscectomy leads to an increase in RBBF in the tibial condyles at a very early stage. This increase might be caused by stress-induced alterations of the subchondral bone.

Direct assessment and distribution of regional portal blood flow in the pig by means of fluorescent microspheres.

Measurement of regional organ blood flow by means of fluorescent microspheres (FM) is an accepted method. However, determination of regional portal blood flow (RPBF) cannot be performed by microspheres owing to the entrapment of the spheres in the upstream capillary bed of the splanchnic organs. We hypothesized that an adequate experimental setting would enable us to measure RPBF by means of FM and to analyze its distribution within the pig liver. A mixing chamber for the injection of FM was developed, and its capability to distribute FM homogeneously in the blood was evaluated in vitro. The chamber was implanted into the portal vein of six anesthetized pigs (23.5 +/- 2.9 kg body wt). Three consecutive, simultaneous injections of FM of two different colors into the chamber were performed. Reference portal blood samples were collected by means of a Harvard pump. At the end of the experiment, the liver was explanted and fixed in formalin before dissection. FM were isolated from the tissue samples by an automated process, and fluorescence intensity was determined. Comparison of 5,458 single RPBF values, determined by simultaneously injected FM, revealed good agreement (bias 2.5%, precision 12.7%) and high correlation (r = 0.97, r2 = 0,95, slope = 1.04, intercept = 0.05). Median RPBF was 1.07 +/- 0.78 ml x min(-1) x g(-1). Allocation of the blood flow values to the anatomic regions of the liver revealed a significantly higher RPBF (P = 0.01) in the liver tissue located close to the diaphragm compared with the rest of the organ and a significantly lower RPBF (P = 0.01) in the left liver lobe compared with the median and right lobes. The results show that the model presented makes it possible to measure RPBF by means of FM reliably and that RPBF is distributed heterogeneously in the porcine liver.

Validity of fluorescent microspheres method for bone blood flow measurement during intentional arterial hypotension.

In this study, we compared bone blood flow values obtained by simultaneously injected fluorescent (FM) and radiolabeled microspheres (RM) at stepwise reduced arterial blood pressure. Ten anesthetized female New Zealand White rabbits received simultaneous left ventricular injections of FM and RM at 90, 70, and 50 mmHg mean arterial blood pressure (MAP). After the experiments, both kidneys and long bones of all four limbs were removed and dissected in a standardized manner. Radioactivity (corrected for decay, background, and spillover) and fluorescence were determined, and blood flow values were calculated. Relative blood flow values estimated for each bone sample by RM and FM were significantly correlated (r = 0.98, slope = 0.99, and intercept = 0.04 for 90 mmHg; r = 0.98, slope = 0.94, and intercept = 0.09 for 70 mmHg; r = 0.98, slope = 0.96, and intercept = 0.07 for 50 mmHg). Blood flow values (ml x min-1 x 100 g-1) of right and left bone samples determined at the different arterial blood pressures were identical. During moderate hypotension (70 mmHg MAP), blood flow in all bone samples remained unchanged compared with 90 mmHg MAP, whereas a significant decrease of bone blood flow was observed at severe hypotension (50 mmHg MAP). Our results demonstrate that the FM technique is valid for measuring bone blood flow. Differences in bone blood flow during altered hemodynamic conditions can be detected reliably. In addition, changes in bone blood flow during hypotension indicate that vasomotor control mechanisms, as well as cardiac output, play a role in setting bone blood flow.

The relation between primary osteoarthritis of the trapeziometacarpal joint and supernumerary slips of the abductor pollicis longus tendon.

We have studied whether accessory abductor pollicis longus slips inserting into the thenar eminence or trapezium influence the incidence and severity of trapeziometacarpal joint osteoarthritis. The right first extensor compartment of 73 cadavers was dissected and trapeziometacarpal degeneration was graded macroscopically. The main abductor pollicis longus tendon which inserted at the metacarpal base was accompanied by supernumerary APL slips in 96% of cases. Thenar or trapezial slips occurred frequently but coexisted in only one case. The incidence of trapeziometacarpal arthritis was not influenced by the number of accessory slips or whether they inserted onto the thenar eminence or the trapezium.

Long-term results of high tibial osteotomy for medial osteoarthritis of the knee.

We reviewed retrospectively the results in patients who had undergone one hundred and four high tibial lateral osteotomies. The operations were all performed between 1985 and 1993. Each one of fifty men and forty nine women demonstrated a varus deformity of the knee with a coexistent medial osteoarthritis. Results were reviewed in 49 patients (62 knees) with an average follow-up of 10.2 years (range 6-14 years). Of the remaining 42 patients, 8 were lost to follow-up, 10 had died, and 24 were subsequently treated with total knee arthroplasty at an average 4.7 years after having had a high tibial osteotomy. Clinical results were evaluated using the Hospital for Special Surgery Score (HSS) and the Knee Society Score. Radiographs were systematically analysed to evaluate osteoarthritis and leg axis. Forty four (90 per cent) of the forty nine patients stated the results met their expectations and given the same circumstances, they would have the operation once again. In these patients the knee score results were excellent. The same patients had excellent HSS and Knee Society Scores. Five patients (10 per cent) had a poor result and twenty four patients were treated later by total knee arthroplasty because of pain. The following factors set these patients apart from those with more favorable results: previous arthroscopic debridement, obesity, lateral knee osteoarthritis, insufficient valgus correction, and an age of more than 55 years. High tibial valgus osteotomy provides good pain relief and improved function in carefully selected patients. Our results support this conclusion.

Medium to long-term results with the cementless threaded Acetabular Munich II type cup.

Compared to pressfit cups, little information exists about the results of screwed cups in hip arthroplasty. 51 cementless or hybrid (cemented stem) primary total hip replacements with a cementless corundium blasted titaniumn alloy threaded Aesculap Munich II type cup were examined with a mean follow up of 7.9 years. 23 of the patients were male and 28 patients were female. From these cups 22 were implanted on the right side and 29 on the left. The results were compared to 53 patients (28 male, 25 female, 29 right side, 24 left side) with the threaded Aesculap Munich I type cup, that has a smooth surface and a direct contact of bone with the polyethylene inlay. The mean follow up ws 10.2 years. The early and medium to long-term clinical and radiographic results show an encouraging improvement of the Merle d'Aubigné Score of the type II cup compared to the type I cup. Two of the Aesculap type Munich II cups had to be revised; four showed radiologic signs of loosening. In conclusion, the threaded Aesculap cup type Munich II seems to be a decisive advance in the development of threaded acetabular hip cups. The intermediate results exceed those from smooth-surface screwed rings and compare favourably with those from cemented cups and with those from cementless press-fit metal-backed cups.

[Dynamic palmar instability of the ulnar head]. / Die dynamische, palmare Ellenkopfinstabilität - Ein Fallbericht -

Despite obvious clinical symptoms, dynamic, palmar instability of the ulnar head remains a diagnostic and therapeutic problem. This is demonstrated by a case of chronic, palmar instability of the ulnar head after a tear of the triangular fibrocartilage complex (TFCC). A concomitant, minimal dorsal angulation of the radius after a fracture in childhood and a general capsulo-ligamentous laxity possibly were predisposing factors. Aspects of diagnostic and therapeutic options are discussed. In our case, due to secondary arthrosis, an arthrodesis of the distal radioulnar joint combined with a stabilization of the TFCC was opted for. Although the patient is painfree and mobile, she complains of a loss of power in supination. This salvage procedure probably could have been avoided by an earlier diagnosis.

[Stress osteotomy of the distal radius- and ulna metaphysis (Illarramendi procedure): an alternative treatment method in lunate necrosis]. / Die Reizosteotomie der distalen Radius- und Ulnametaphyse (MRO nach Illarramendi): Eine alternative Behandlungsmethode der Lunatumnekrose.

The etiology of Kienböck's disease is still unknown. Many operative procedures, usually based on biomechanical considerations, are recommended. Based on known effects of core decompression procedures on bone, we present a technique of core decompression of the metaphysis of the distal radius and ulna (MCD) as an easy, alternative biologic treatment. Ten cases with a mean follow-up of 10.8 years are analyzed. All patients had significant postoperative pain relief and returned to their previous activities. At the time of follow-up, comparative motion of flexion-extension of the wrist averaged 74%, mean grip strength was 81% of the nonaffected side. Radiographic follow-up did not slow significant postoperative collapse of the lunate (p > 0.05). No correlation was observed between post-operative results and ulnar variance. MCD is a simple, low-risk procedure. Clinical and radiological outcome supports a theory of biologic rather than biomechanic mechanisms related to fracture healing, that stimulate regeneration of the avascular lunate and relieve symptoms. A primary vascular etiology of idiopathic avascular necrosis of the lunate seems to be likely.

The effect of closed- and open-wedge high tibial osteotomy on tibial slope: a retrospective radiological review of 120 cases.

Radiographs of 110 patients who had undergone 120 high tibial osteotomies (60 closed-wedge, 60 open-wedge) were assessed for posterior tibial slope before and after operation, and before removal of the hardware. In the closed-wedge group the mean slope was 5.7 degrees (SD 3.8) before and 2.4 degrees (SD 3.9) immediately after operation, and 2.4 degrees (SD 3.4) before removal of the hardware. In the open-wedge group, these values were 5.0 degrees (SD 3.7), 7.7 degrees (SD 4.3) and 8.1 degrees (SD 3.9) respectively, when stabilised with a non-locking plate, and 7.7 degrees (SD 3.5), 9.4 degrees (SD 4.1) and 9.1 degrees (SD 3.8), when stabilised with a locking plate. The reduction in slope (-2.7 degrees (SD 4.1)) in the closed-wedge group and the increase (+2.5 degrees (SD 3.4), in the open-wedge group was significantly different before and after operation (p = 0.002, p = 0.003). In no group were the changes in slope directly after operation and before removal of the hardware significant (p > 0.05). There was no correlation between the amount of correction in the frontal plane and the post-operative change in slope. Posterior tibial slope decreases after closed-wedge high tibial osteotomy and increases after an open-wedge procedure because of the geometry of the proximal tibia. The changes in the slope are stable over time, emphasising the influence of the operative procedure rather than of the implant.

[Pathologic glenohumeral stress distribution in calcific tendinosis of the supraspinatus]. / Glenohumerale Fehlbeanspruchung bei Tendinosis calcarea der Supraspinatussehne.

AIM: Based on hypothesis that calcific tendonitis of the supraspinatus tendon (CTSSP) could be associated with glenohumeral imbalance, glenohumeral stress distribution was analyzed. METHODS: 26 patient shoulders with CTSSP, unsuccessfully treated by non-operative measures, were examined. A group of 26 macroscopically normal shoulder specimens served as controls. Analysis of glenohumeral stress distribution was indirect evaluating glenoid subchondral bone mineralization by computed tomography osteoabsorptiometry. Density distribution of glenoid subchondral bone mineralization and the position of the two most frequent density maxima were analyzed. RESULTS: Patterns of subchondral mineralization and position of the anterior density maximum were significantly different between both groups. CTSSP mostly presented with a monocentric, anteriorly increased mineralization indicative for a regional increase of stress. The inferior shift of the anterior density maximum demonstrates a parallel shift of glenohumeral stress distribution. CONCLUSION: Mineralization patterns indicate that glenohumeral stress distribution is not physiologic in CTSSP. Moreover, it is comparable with glenohumeral stress distribution as observed in atraumatic antero-inferior glenohumeral instability. Relevance of this observation should be proven for etiology of CTSSP.

[Morphometry of the sub-acromial space and its clinical relevance]. / Die Morphometrie des subakromialen Raums und ihre klinische Relevanz.

Rupture of the rotator cuff is one of the commonest (30%) pathologic findings in elderly dissecting room subjects. Together with the degenerative tendopathy associated with increasing age, this is due to mechanical damage to the distal parts of the tendons or the soft tissues lying in the subacromial space between the acromion, coracoacromial ligament, coracoid process and humeral head. The object of this investigation was to examine the influence of the decisive metrical parameters of the subacromial space in the macerated scapula. For this purpose, defined distances and angles of 343 macerated human scapulae were measured by means of an image analysing system, and the results evaluated statistically. It was found that the size of the subacromial space depends, not only upon variations in the form of the acromion itself, but also upon the acromial and scapula-spine angles. Marked projection of the coracoid process, which is dependent upon both the angle between the long axis of the scapula and the root of the coracoid process and the coracoid angle, plays an important part in the development of the so-called subcoracoid impingement syndrome: a constriction of the subscapularis tendon between the coracoid process and the head of the humerus. A clinical assessment of the absolute size of the subacromial space should take into account the size of the body; but sex, age, and the side involved are of little significance.

The scapula: principles of construction and stress.

According to current generally accepted theories, analysis of the shape of a bone provides clues to the stresses acting upon it. Although many investigations have ensured that understanding of the lower limb is relatively advance, knowledge relating to the upper limb, and particularly to the scapula, is still far from complete. We have therefore endeavoured to interpret the shape of this bone morphometrically. To this end various scapular parameters have been standardised and statistically analysed, and the results examined both from the functional and the clinical points of view. Our investigation has established that, as in the case of the long bones, the form of the scapula is dependent upon both height and sex. Assessment of the architecture of the subacromial space and its possible parameters of influence have also demonstrated that the size of this space is essentially dependent upon the height of the subject and the size of the acromial and scapulospinal angles. A short distance between the acromion and the upper edge of the glenoid cavity and a small glenoid-spinal angle can be regarded from a functional point of view as factors predisposing to the development of the impingement syndrome. We have also been able to show that certain constant structural features produce an optimal distribution of the forces acting upon the scapula. In particular, the relationship of the supporting pillars (the lateral border and the spine) of this bone to one another appears to represent the expression of an ideal adaptation to the action of those forces.

Determination of regional bone blood flow by means of fluorescent microspheres using an automated sample-processing procedure.

The determination of regional blood flow utilizing fluorescent microspheres (FMs) is an established method for numerous organs. Recent progress, in particular the automation of sample processing, has further improved this method. However, the FM method (reference sample technique), which allows repetitive measurement of regional organ blood flow, has so far not been used for the determination of blood flow in bone. The aim of the present study was to establish FM for the quantification of regional bone blood flow (RBBF). Female, anesthetized New Zealand rabbits (n = 6) received left ventricular injections of different amounts of FM at six subsequent time points. In order to examine the precision of RBBF determination, two different FM species were injected simultaneously at the sixth injection. At the end of the experiments the femoral and tibial condyles of each hind limb were removed and the fluorescence intensity in the tissue samples was measured by an automated procedure. In an in vitro study we have shown that acid digestion of the crystalline matrix has no effect on the fluorescence characteristics of FM. The determination of the number of spheres per tissue sample revealed that depending on the tissue sample size up to 3 x 10(6) spheres/injection were necessary to obtain about 400 microspheres in the individual bone samples. RBBF values of the tibial and femoral condyles did not differ at various injection intervals. The tibial blood flow values varied between 6.6 +/- 1.1 and 8.5 +/- 1.4 ml/min/100 g and were significantly higher than those of the femur (4.3 +/- 1.1 to 6.0 +/- 1.8 ml/min/100 g). The bone blood flow values obtained by simultaneous injection of two FM species correlated significantly (r = 0.96, slope = 1.06, intercept = 0.05), the mean difference was 0.39 +/- 1.11 ml/min/100 g. Our data demonstrate that the measurement of RBBF by means of FM allows a valid determination of RBBF.

Thickness of the subchondral mineralised tissue zone (SMZ) in normal male and female and pathological human patellae.

The objective of this paper was to analyse sex differences of the thickness of the subchondral mineralised tissue zone (SMZ), and to find out whether systematic changes of SMZ thickness are associated with naturally occurring, non-full-thickness cartilage lesions of human patellae. In 32 methyl-methacrylate-embedded specimens (16 normal, 8 with focal medial, and 8 with lateral lesions) the SMZ thickness was determined, using a binocular macroscope and an image analysing system. In each case, the thickness distribution was reconstructed throughout the entire joint surface. The maximal and mean SMZ thicknesses were significantly higher in males than in females (P < 0.01). In normal patellae and those with lateral lesions, the thickness was significantly thicker laterally than medially (P < 0.05), but it was not in specimens with medial damage. Patellae with medial damage exhibited a significantly lower total mean and lateral mean (P < 0.05). A lower SMZ thickness was found directly beneath medial lesions than beneath lateral ones, but the local thickness was always in the range of that observed in normal specimens. We conclude that differences of patellar SMZ thickness exist between males and females. Naturally occurring cartilage lesions appear, however, not to be associated with local changes of SMZ thickness, but they may be associated with an altered regional distribution pattern within the joint surface.

Fluorescent microspheres are reliable for serial bone blood flow measurements.

The fluorescent microsphere method is one of the current techniques to determine regional blood flow in various organs. The purpose of this study was to examine the suitability of fluorescent microspheres for serial measurement of regional bone blood flow. Six anesthetized female New Zealand rabbits received five left ventricular injections of fluorescent microspheres in 20-minute intervals. To test the precision of the measurement two types of fluorescent microspheres were injected simultaneously at the first and last injections. Blood flow was calculated in the kidneys, lungs, brain, femurs, and tibias after measuring the fluorescence intensity in each reference blood and tissue sample. Comparison of blood-flow values obtained by simultaneously injected microspheres showed an excellent correlation and a minimal percentage difference at the first and last injections, indicating valid measurements of regional bone blood flow. No significant differences were observed when comparing blood flow in the corresponding regions of bones on the right side and left side. Mean blood flow in the femur and tibia significantly increased at the fourth injection whereas flow distribution within the femur and tibia essentially remained unchanged throughout the experiment. Comparison of blood flow values obtained by simultaneously injected microspheres showed moderate agreement for the kidneys and lungs at the last injections. Because this finding might be attributable to disturbances of microcirculation caused by accumulation of spheres in high-flow organs, the increase in regional bone blood flow observed in our experiments has to be interpreted carefully. This study showed that bone blood flow can be determined reliably in anesthetized rabbits by as many as three serial injections of fluorescent microspheres.

[The architecture of the subacromial space after full thickness supraspinatus tears]. / Die Architektur des subakromialen Raumes bei Supraspinatussehnenruptur.

AIM: The etiology of rotator cuff tears is multifactorial. An important factor is the damage of the rotator cuff by narrowing of the subacromial space. The purpose of this investigation was to estimate the influence of various metrical parameters on the size of the subacromial space. METHOD: We investigated 161 human macerated scapulae, 36 of them had a known tear of the supraspinatus tendon. All scapulae were photographed in two standard positions from the front and the lateral side. Defined distances and angles were measured using an image analyzing system followed by statistical analysis. RESULTS: Shoulders with a tear of the supraspinatus tendon showed a trend towards higher incidences of hooked acromions. Furthermore we found a significant higher incidence of elongated oval shaped glenoids in the group with supraspinatus tendon tear. In comparison to normal shoulders a significantly smaller distance from the top of the glenoid to the tip of the acromion and a greater distance from the top of the glenoid to the tip of the coracoid process was measured. In addition there was a significantly smaller coracoid angle and a smaller glenoid-spinal angle in this group. CONCLUSION: The width of the subacromial space depends on various parameters. Our data suggest that besides the acromion type the shape of the coracoid, the acromial angle, the spine-scapula angle and the cavitas-spine angle should be taken into account for diagnostic and therapeutic decisions.