Humeral head necrosis after proximal humeral nailing: what are the reasons for bad outcomes?

INTRODUCTION: Humeral head necrosis (HHN) remains a major problem in fracture care. Neither its occurrence, its extend, nor its impact on clinical outcomes is predictable on the long term. This study was designed to evaluate clinical and radiological outcomes in patients depending on the influence of HHN. PATIENTS AND METHODS: 32 patients with a 3-6 year follow up participated in this study. Their humeral fractures had been stabilized with a standard Targon PH nail (Aesculap, Tuttlingen, Germany) for an acute humeral head fracture. Constant score (CS), DASH score, UCLA shoulder rating scale, and Neer score were assessed. Range of motion (ROM) as well as pain during exercise was documented (VAS). HHN was detected radiologically and graded in stages 0-5. RESULTS: All fractures had healed. HHN was found in 10 cases (31.3%). 4 patients (12.5%) showed interlocking screw perforation as part of the head collapse caused by HHN. Median CS was 73 (range: 24-85). There was no association detectable between number of fracture fragments and CS (p ≥ 0.631). The median DASH score was 16.4 (range: 0-74.1), UCLA score 30 (range: 9-35), Neer score 80 (range: 29-100). Three (37.5%) of the patients with a stage IV or V osteonecrosis reported about pain (twice VAS grade 4, once VAS grade 5). All patients suffering from pain were affected by high grade HHN and screw perforation. CS was nonsignificantly affected by HHN (75.5 vs. 63.5; p = 0.12), however massively diminished if additional implant protrusion was present (63.5 vs. 25; p = 0.02). Findings for normalised CS, relative CS, DASH score, UCLA shoulder rating scale, Neer score, and ROM were analogous. DISCUSSION: Whereas HHN itself seems to contribute only mildly to functional outcome, we identified screw protrusion as major predictor for bad clinical results. The high rate of HHN found in our study (31.3%) may be attributed to the inclusion of mild HHN and our long follow-up period, as it is known that late-onset HHN may occur more than 3 years after trauma. CONCLUSIONS: HHN may lead to screw perforation, resulting in poorest outcomes. We recommend regular clinical and radiographic follow-up for at least five years in order to detect impending screw perforation and plan screw removal in time.

How to prevent cut-out and cut-through in biaxial proximal femoral nails: is there anything beyond lag screw positioning and tip-apex distance?

PURPOSE: Hip perforation is a major complication in proximal femoral nailing. For biaxial nails, knowledge of their biomechanics is limited. Besides re-evaluation of accepted risk factors like the tip-apex distance (TAD), we analysed the influence of anti-rotational pin length. METHODS: We compared 22 hip perforation cases to 50 randomly chosen controls. TAD, lag-screw position, angle between lag-screw and femoral neck axis, lag-screw gliding capacity, displacement and anti-rotational pin length were investigated. RESULTS: Hip perforation was associated with a higher angle of deviation between lag-screw and femoral neck axis (p = 0.001), a lower telescoping capacity of the lag screw (p = 0.02), and higher TAD (p = 0.048). If the anti-rotational pin exceeded a line connecting the tip of the nail and the lag screw (NS line), hip perforation incidence was increased (p = 0.009). Inadequate pin length resulted in an odds ratio of 10.8 for hip perforation (p = 0.001). CONCLUSIONS: In biaxial nails anti-rotational element positioning is underestimated, however, crucial.

An innovative technique of rear entry creation for retrograde humeral nailing: how to avoid iatrogenic comminution.

BACKGROUND: Antegrade and retrograde nails are widely used for intramedullary fixation of humeral shaft fractures. Creating the rear entry is the crucial step for retrograde nailing. The common manual technique is associated with considerable risks of additional iatrogenic comminution of the distal humerus. DESCRIPTION OF THE TECHNIQUE: A specific device for the creation of a rear entry hole has been developed as part of the instruments for humeral shaft nailing (Targon H) and made commercially available (BBraun Aesculap, Germany). After standard triceps-splitting approach, a guide instrument is firmly applied to the distal humerus with one screw. The screw hole is later used for distal interlocking. The oval rear entry hole is then performed by frontal cutter along the guide. PATIENTS AND METHODS: We have been performing a retrospective evaluation of all unreamed humeral nailings (Targon H) since 2000. Operation time, use of the guide instrument and intra-operative problems were analysed. X-rays were checked for iatrogenic humeral comminution directly after the operation and after physiotherapy. Cases of infection and nonunion were noted. RESULTS: We identified 87 cases of intramedullary fracture fixation with an interlocking nail (46 antegrade, 41 retrograde). In all retrograde cases a guide instrument and an access reamer were used for the creation of an entry hole. No iatrogenic comminutions were observed during the operation or on postoperative X-rays. Active postoperative exercises were generally allowed in every patient. Mean operative time was shorter for retrograde than for antegrade nailing (90 min vs. 108 min; p = 0.012). We saw two nonunions (2%) and no infections. CONCLUSIONS: Use of access reamer and guide instrument is a safe and reproducible way of creating a rear entry hole for retrograde humeral nailing. The risk of additional comminution seems to be eliminated.