Stefan Greiner

Prevalence and pattern of glenohumeral injuries among acute high-grade acromioclavicular joint instabilities.

BACKGROUND With increasing numbers of arthroscopically assisted acromioclavicular (AC) joint stabilization procedures has come an increase in reports of concomitant glenohumeral injuries among AC joint separations. The aim of the present study was to evaluate the prevalence, pattern, and cause of glenohumeral pathologies among a large patient population with acute high-grade AC joint instability. MATERIALS AND METHODS A total of 125 patients (13 women, 112 men) with high-grade AC joint dislocation (6 Rockwood II; 119 Rockwood V) underwent diagnostic glenohumeral arthroscopy before AC joint repair. Pathologic lesions were evaluated for acute or degenerative origin and, if considered relevant, treated all-arthroscopically. RESULTS Concomitant glenohumeral pathologies were found in 38 of 125 patients (30.4%). Analysis of pathogenesis distinguished different patterns of accompanying injuries: acute intra-articular lesions, related to the recent shoulder trauma, were found in 9 patients (7.2%), degenerative lesions, considered to be unrelated to the recent trauma, were found in 18 (14.4%), and 11 (8.8%) had an unclear traumatic correlation (intermediate group). Within the acute and the degenerative group, affected structures were predominantly partial, articular-sided tears of the anterosuperior rotator cuff, including instabilities of the pulley complex, followed by pathologies of the long head of the biceps and superior labrum anteroposterior lesions. The intermediate group presented mainly with articular-sided partial tears of the subscapularis tendon. CONCLUSIONS This prospective study showed a high prevalence (30%) of concomitant glenohumeral pathologies, of which some indicate additional surgical therapy and could be missed by an isolated open AC repair. Hence, the arthroscopic approach for AC joint stabilization allows for the diagnosis and treatment of associated intra-articular pathologies.

Humeral head necrosis rate at mid-term follow-up after open reduction and angular stable plate fixation for proximal humeral fractures

INTRODUCTION Short-term follow-up of angular stable fixation for proximal humeral fractures has been well documented in the literature. Longer follow-up series are difficult to find. However, especially regarding the risk of avascular humeral head necrosis longer follow-up series are high of clinical relevance. METHODS Forty-eight patients with a mean age of 66 years and treated with open reduction and angular stable internal fixation for proximal humeral fractures were followed up for a mean of 45 months. The clinical and radiographic follow-up (Constant Score (CS), age and gender related Constant Score (agCS), Constant Score in comparison to the contralateral side (%CS) and shoulder anterior-posterior and lateral view and axial view X-rays) was performed postoperatively. RESULTS Clinical results after 45 months showed a mean CS of 66.2+/-15.4 points with a mean agCS of 90.0+/-23.1%. Evaluation of the %CS showed 77.7+/-17.8%. %CS results showed no significant differences after 45 months in comparison to those obtained after 12 months. However, incidence of avascular necrosis of the humeral head doubled over the follow-up period from 4 cases at 12 months follow-up to 9 cases at final follow-up. CONCLUSION Results of open reduction and internal fixation with angular stable implants for proximal humeral fractures are reliable, however long-term complications such as avascular necrosis of the humeral head need to be evaluated further on since its incidence increases over the time.

Stabilisation of vertical unstable distal clavicular fractures (Neer 2b) using locking T-plates and suture anchors

Distal clavicular fractures are associated with an increased risk of delayed union and non-union, and therefore operative treatment is favoured. Fragment dislocation and instability result from detachment of the coracoclavicular ligaments. Various methods for operative treatment can be found in the literature, but no gold standard has been established. In this retrospective study, we present a new surgical technique using a locking T-plate for osseous stabilisation in combination with vertical stabilisation by suture anchors. Between October 2006 and December 2007, eight people underwent surgery for unstable distal clavicular fracture (Neer type 2b). Subsequently one patient could only be contacted by phone and was excluded from further analysis. Mean follow-up for the remaining seven individuals was 8.3 months. The Constant and DASH scores were evaluated and stress radiographs were performed to check for vertical instability. In all cases bony union was achieved within 6 weeks postoperatively. No intraoperative or early postoperative complications were observed. All but one patient regained excellent shoulder function, the mean Constant and DASH scores were 93.3 and 15.3, respectively. Coracoclavicular distance was successfully restored with a mean 1mm (range 0-2mm) side-to-side difference. Early clinical and radiographic results of this new method are promising, with good to excellent outcome in all cases.

Tuberosity position correlates with fatty infiltration of the rotator cuff after hemiarthroplasty for proximal humeral fractures

HYPOTHESIS This study investigates the correlation between tuberosity positioning, fatty infiltration of the rotator cuff, and clinical outcome after hemiarthroplasty for proximal humeral fracture. MATERIALS AND METHODS Twenty patients with a mean age of 70.8 +/- 9.9 years were evaluated at a mean of 19.8 +/- 9.4 months. Evaluation included assessment of the Constant score (CS); Disabilities of the Arm, Shoulder and Hand (DASH) score; radiographic evaluation; and computed tomography to classify healing of the tuberosities and changes in the rotator cuff. Fatty degeneration of the cuff was classified according to the Goutallier classification as stage 0 to 4. Tuberosity positioning was classified as mal-positioning of less than 0.5 cm., 0.5 to 1 cm., >1.0 cm., or not healed. RESULTS The mean Constant Score (CS) of patients with greater tuberosity displacement of <0.5 cm was significantly higher than the CS of patients with > or =0.5 cm displacement and non-united greater tuberosities. The CS of patients with greater tuberosity displacement of 0.5 to 1 cm was significantly higher than that in patients with non-united greater tuberosities. For the lesser tuberosity, patients with displacement of <0.5 cm showed significantly higher outcome scores than patients with displacement of >1 cm and non-united lesser tuberosities. There was a significant correlation between fatty infiltration of the supraspinatus and infraspinatus muscles and greater tuberosity malposition and between fatty infiltration of the subscapularis and lesser tuberosity malposition. CONCLUSION Fatty infiltration of the cuff was significantly associated with lower clinical scores. Tuberosity positioning and healing are critical for improved clinical outcomes after hemiarthroplasty for proximal humeral fractures.

Local application of zoledronic acid incorporated in a poly(D,L-lactide)-coated implant accelerates fracture healing in rats

Background and purpose Zoledronic acid (ZOL) has been shown in vitro and in vivo to inhibit osteoclastic activity and to regulate osteoblasts. Its antiresorptive effect is used clinically in the treatment of bone-consuming pathologies to prevent skeletal complications. Because of its effect on bone cells, there might be a possible benefit in treatment of fractures by local application from a biodegradable poly(D,L-lactide) (PDLLA) coating of osteosynthetic implants. We analyzed the effect of locally applied ZOL from a PDLLA coating of intramedullary implants on fracture healing. Material and methods Standardized midshaft fractures of the right tibia of 5-month-old rats were stabilized either with uncoated, PDLLA-coated, or ZOL-coated implants. Animals were killed 42 or 84 days after fracture. Tibiae were dissected and mechanically tested. Results Radiographs taken 42 days after fracture showed at least unilateral bridging in all groups. Maximum load and torsional stiffness were highest in the group treated with ZOL. 84 days after fracture, the torsional stiffness of the ZOL-treated group remained higher than that of the uncoated group whereas the maximum load for the control groups reached the results for the ZOL-coated group. Interpretation Local application of ZOL from PDLLA coating appears to accelerate the achievement of mechanical stability in fractures.

Diagnostic values of clinical tests for subscapularis lesions.

Subscapularis (SSC) lesions are often underdiagnosed in the clinical routine. This study establishes and compares the diagnostic values of various clinical signs and diagnostic tests for lesions of the SSC tendon. Fifty consecutive patients who were scheduled for an arthroscopic subacromial or rotator cuff procedure were clinically evaluated using the lift-off test (LOT), the internal rotation lag sign (IRLS), the modified belly-press test (BPT) and the belly-off sign (BOS) preoperatively. A modified classification system according to Fox et al. (Type I–IV) was used to classify the SSC lesion during diagnostic arthroscopy. SSC tendon tears occured with a prevalence of 30% (15 of 50). Five type I, six type II, three type IIIa and one type IIIb tears according to the modified classification system were found. Fifteen percent of the SSC tears were not predicted preoperatively by using all of the tests. In six cases (12%), the LOT and the IRLS could not be performed due to a painful restricted range of motion. The modified BPT and the BOS showed the greatest sensitivity (88 and 87%) followed by the IRLS (71%) and the LOT (40%). The BOS had the greatest specificity (91%) followed by the LOT (79%), mod. BPT (68%) and IRLS (45%). The BOS had the highest overall accuracy (90%). With the BOS and the modified BPT in particular, upper SSC lesions (type I and II) could be diagnosed preoperatively. A detailed physical exam using the currently available SSC tests allows diagnosing SSC lesions in the majority of cases preoperatively. However, some tears could not be predicted by preoperative assessment using all the tests.

Reconstruction of humeral length and centering of the prosthetic head in hemiarthroplasty for proximal humeral fractures

Anatomic reconstruction of humeral length in hemiarthroplasty for complex proximal humeral fractures is difficult because reliable surgical landmarks are missing or are destroyed by the fracture. The pectoralis major tendon is a reliable landmark to determine prosthetic height intraoperatively. This study analyzed the clinical outcome, reconstruction of humeral length, centering of the prosthetic head in the glenoid, and tuberosity positioning and healing, using the pectoralis major tendon as a reference intraoperatively. The study included 30 patients. In 21 patients (group 1), humeral length reconstruction was performed using the pectoralis major tendon as a reference; in 9 (group 2), this reference was not used. Patients underwent a clinical and radiologic evaluation at a mean of 22.7 months. Group 1 showed significantly better results in clinical and radiologic values, especially in anatomic reconstruction of humeral length, than group 2. Clinical outcome depended significantly on greater tuberosity healing and centering of the prosthetic head in the glenoid.

Three-dimensional distribution of trabecular bone density and cortical thickness in the distal humerus

BACKGROUND One major barrier to osteosynthesis in distal humeral fractures is poor bone quality. This study was an attempt to measure the bone quality in the distal humerus. METHODS We measured the distribution of total bone mineral density (BMD), trabecular BMD (tBMD), and cortical thickness (CTh) in the distal humerus using peripheral quantitive computed tomography. Four slices in the infracondylar, supracondylar, and distal disphyseal regions of 25 human cadaver humeri were investigated. RESULTS Total BMD decreased continuously from the distal diaphysis to the trochlea. Within the infracondylar region, the capitellum was the region of lowest tBMD and CTh (P < .001). Measurements in anterior regions were higher than in most others (P < .001). The tBMD of the medial column in the infracondylar and supracondylar regions was 31% and 36% higher vs the lateral column (P < .001). The medial column had an average 22% higher CTh in the supracondylar and 38% higher CTh in distal diaphyseal regions vs the lateral sides (P < .001). CONCLUSIONS Distal humeral bone properties vary widely, providing stronger bone stock on the medial side. This may improve understanding of implant failure and techniques in surgical treatment.

Effect of local zoledronate on implant osseointegration in a rat model

BackgroundAn implant coating with poly(D, L-lactide) (PDLLA) releasing incorporated Zoledronic acid (ZOL) has already proven to positively effect osteoblasts, to inhibit osteoclasts and to accelerate fracture healing. Aim of this study was to investigate the release kinetics of the chosen coating and the effect of different concentrations of ZOL locally released from this coating on the osseointegration of implants.MethodsFor release kinetics the release of C14-labled ZOL out of the coating was monitored over a period of six weeks in vitro. For testing the osseointegration, titanium Kirschner wires were implanted into the medullary canal of right femurs of 100 Sprague Dawley rats. The animals were divided into five groups receiving implants either uncoated or coated with PDLLA, PDLLA/ZOL low (1.2% w/w) or PDLLA/ZOL high (2% w/w). Additionally, a group with uncoated implants received ZOL intravenously (i.v.). After 56 days animals were sacrificed, femurs dissected and either strength of fixation or histological bone/implant contacts and newly formed bone around the implants were determined.ResultsRelease kinetics revealed an initial peak in the release of C14-ZOL with a slight further progression over the following weeks. There was no significant enhancement of osseointegration for both groups who received ZOL-coated implants or ZOL i.v. compared to the controls in biomechanical or histological analyses, except for a significant raise in strength of fixation of ZOL i.v. versus PDLLA.ConclusionsEven though the investigated local ZOL application did not enhance the osseointegration of the implant, the findings might support its application in fracture treatment, since fracture stabilization devices are often explanted after consolidation.

Characterization of a rat osteotomy model with impaired healing.

BackgroundDelayed union or nonunion are frequent and feared complications in fracture treatment. Animal models of impaired bone healing are rare. Moreover, specific descriptions are limited although understanding of the biological course of pathogenesis of fracture nonunion is essential for therapeutic approaches.MethodsA rat tibial osteotomy model with subsequent intramedullary stabilization was performed. The healing progress of the osteotomy model was compared to a previously described closed fracture model. Histological analyses, biomechanical testing and radiological screening were undertaken during the observation period of 84 days (d) to verify the status of the healing process. In this context, particular attention was paid to a comparison of bone slices by histological and immunohistological (IHC) methods at early points in time, i.e. at 5 and 10 d post bone defect.ResultsIn contrast to the closed fracture technique osteotomy led to delayed union or nonunion until 84 d post intervention. The dimensions of whole reactive callus and the amounts of vessels in defined regions of the callus differed significantly between osteotomized and fractured animals at 10 d post surgery. A lower fraction of newly formed bone and cartilaginous tissue was obvious during this period in osteotomized animals and more inflammatory cells were observed in the callus. Newly formed bone tissue accumulated slowly on the anterior tibial side with both techniques. New formation of reparative cartilage was obviously inhibited on the anterior side, the surgical approach side, in osteotomized animals only.ConclusionTibial osteotomy with intramedullary stabilisation in rats leads to pronounced delayed union and nonunion until 84 d post intervention. The early onset of this delay can already be detected histologically within 10 d post surgery. Moreover, the osteotomy technique is associated with cellular and vascular signs of persistent inflammation within the first 10 d after bone defect and may be a contributory factor to impaired healing. The model would be excellent to test agents to promote fracture healing.