Intra-operative digital imaging: assuring the alignment of components when undertaking total hip arthroplasty

Aims

The aims of this study were to examine the rate at which the positioning of the acetabular component, leg length discrepancy and femoral offset are outside an acceptable range in total hip arthroplasties (THAs) which either do or do not involve the use of intra-operative digital imaging.

Patients and Methods

A retrospective case-control study was undertaken with 50 patients before and 50 patients after the integration of an intra-operative digital imaging system in THA. The demographics of the two groups were comparable for body mass index, age, laterality and the indication for surgery. The digital imaging group had more men than the group without. Surgical data and radiographic parameters, including the inclination and anteversion of the acetabular component, leg length discrepancy, and the difference in femoral offset compared with the contralateral hip were collected and compared, as well as the incidence of altering the position of a component based on the intra-operative image.

Results

Digital imaging took a mean of five minutes (2.3 to 14.6) to perform. Intra-operative changes with the use of digital imaging were made for 43 patients (86%), most commonly to adjust leg length and femoral offset. There was a decrease in the incidence of outliers when using intra-operative imaging compared with not using it in regard to leg length discrepancy (20% versus 52%, p = 0.001) and femoral offset inequality (18% versus 44%, p = 0.004). There was also a difference in the incidence of outliers in acetabular inclination (0% versus 7%, p = 0.023) and version (0% versus 4%, p = 0.114) compared with historical results of a high-volume surgeon at the same centre.

Conclusion

The use of intra-operative digital imaging in THA improves the accuracy of the positioning of the components at THA without adding a substantial amount of time to the operation.

Cite this article: Bone Joint J 2018;100B(1 Supple A):36–43.

Aspirin and the prevention of venous thromboembolism following total joint arthroplasty: commonly asked questions

The number of arthroplasties being performed increases each year. Patients undergoing an arthroplasty are at risk of venous thromboembolism (VTE) and appropriate prophylaxis has been recommended. However, the optimal protocol and the best agent to minimise VTE under these circumstances are not known. Although many agents may be used, there is a difference in their efficacy and the risk of bleeding. Thus, the selection of a particular agent relies on the balance between the desire to minimise VTE and the attempt to reduce the risk of bleeding, with its undesirable, and occasionally fatal, consequences.

Acetylsalicylic acid (aspirin) is an agent for VTE prophylaxis following arthroplasty. Many studies have shown its efficacy in minimising VTE under these circumstances. It is inexpensive and well-tolerated, and its use does not require routine blood tests. It is also a ‘milder’ agent and unlikely to result in haematoma formation, which may increase both the risk of infection and the need for further surgery. Aspirin is also unlikely to result in persistent wound drainage, which has been shown to be associated with the use of agents such as low-molecular-weight heparin (LMWH) and other more aggressive agents.

The main objective of this review was to summarise the current evidence relating to the efficacy of aspirin as a VTE prophylaxis following arthroplasty, and to address some of the common questions about its use.

There is convincing evidence that, taking all factors into account, aspirin is an effective, inexpensive, and safe form of VTE following arthroplasty in patients without a major risk factor for VTE, such as previous VTE.

Cite this article: Bone Joint J 2017;99-B:1420–30.

Proprioception after unicondylar knee arthroplasty versus total knee arthroplasty

Proprioception was measured in 2 groups of patients after successful knee arthroplasty. Twenty-eight patients had total knee arthroplasty and their results were compared with an age matched group of 10 subjects who had undergone unicondylar knee arthroplasty. The threshold to detection of passive motion was quantified as a measure of proprioception. The degree of preoperative arthritis was objectively classified according to Resnick. The anterior cruciate ligament and posterior cruciate ligament were present and preserved in all the patients who had undergone unicondylar knee arthroplasty. The anterior cruciate ligament was sacrificed and posterior cruciate ligament retained in 15 of the patients who had total knee arthroplasty and the anterior cruciate ligament and posterior cruciate ligament were sacrificed in 13 of the patients who had total knee arthroplasties. There was no difference in threshold to detection of passive motion among any of the 3 groups. Maintaining the anterior cruciate ligament and posterior cruciate ligament did not impart improved proprioception in unicondylar knee arthroplasty nor did maintaining the posterior cruciate ligament impart improved proprioception in total knee arthroplasty.

Heterotopic ossification following uncemented total hip arthroplasty. Effect of the operative approach

A consecutive series of 112 primary uncemented total hip arthroplasties using the same type of prosthesis was reviewed for the incidence and severity of heterotopic ossification (HO). Sixty-three of these patients underwent a posterior approach (group 1) and 49 underwent an anterolateral approach (group 2). The two groups were virtually identical when risk factors, such as age, sex, estimated blood loss, length of surgery, and diagnosis were compared. Patients in group 1 had a significantly lower incidence and severity of HO than those in group 2. The overall incidence of class III or IV HO was very low (8%), indicating that uncemented total hip arthroplasty in itself is not predisposed to moderate or severe degrees of HO. Patients undergoing uncemented total hip arthroplasty through an anterolateral approach had a higher incidence of HO than those undergoing a posterior approach in this series.

Clinical presentation of complete tears of the rotator cuff

To determine whether the presence and extent of a tear of the rotator cuff could be predicted on the basis of a patient's history, physical examination, and radiographic findings, detailed data from the histories and physical examinations of 103 patients who were known to have a tear of the rotator cuff were correlated with the radiographic and operative findings on these patients. An age-matched control group of fifty-one patients who had similar symptoms, but whose arthrograms showed normal results, was used to establish a baseline incidence of ten specific radiographic findings in the shoulder. Two discrete groups of patients who had a tear of the rotator cuff were identified. Twenty-eight patients (27 per cent) had a tear of a single tendon; the histories and the physical and radiographic findings in this group were consistent with a symptomatic local mechanical-impingement process in the shoulder. Sixty (80 per cent) of the seventy-five patients in the other group had a history of acute trauma to a shoulder. The patients in this second group were older and were non-athletic, and had not previously had symptoms that were severe enough to need treatment. These patients were subsequently found to have a complete tear of more than one of the tendons of the rotator cuff. Multiple radiographic findings in the shoulder and other coexisting orthopaedic conditions also were more common in these patients. In this group, we believe that acute trauma in a shoulder that had chronic degenerative changes, rather than localized mechanical impingement, caused the tendons to rupture.