This study reports the mid-term results of a large bearing uncemented metal on metal total hip replacement (MOMHTHR) matched series using the Synergy stem and Birmingham modular head in 36 hips (mean follow up 61 months). All patients underwent clinical, metal ion and MRI assessment. Wear analysis was performed on retrieved heads using Redlux non-contact optical profilometry.

Seven patients (19%) have undergone revision surgery. All revisions had two or more of either symptoms, high metal ions or an MRI suggestive of an adverse reaction to metal debris (ARMD). There was no evidence of component malposition or impingement. Frank staining of tissues together with high volume dark brown fluid collections were found in all cases. All stems and cups were well fixed. In 4 cases pubic and ischial lysis (adjacent to the inferior fins) was observed. All 7 cases had radiological, intraoperative and histological evidence of ARMD (Figure 1). The failure cohort had significantly higher whole blood cobalt ion levels and OHS (p = 0.001), but no significant difference in cup size (p = 0.77), gender predominance, stem offset or cup position (p = 0.12). Sleeves had been used in all revision cases

Wear analysis (n = 4) demonstrated increased wear at the trunnion/sleeve interface in a distribution compatible with micromotion (Figure 2). There was normal wear at the articulating surface.

This series further demonstrates unacceptable failure rates in LHMOMTHR in a series where a compatible stem for the BHR modular head was used. Use of a CoCr sleeve within a CoCr head taper appears to contribute to abnormal wear and therefore potential ARMD and subsequent failure.

Background: Chronic compartment syndrome is well recognised. Patients present with exercise-induced pain, relieved by rest. The condition is caused by increased intra-compartmental pressure due to inadequate muscle/fascial compartment size. Cases of forearm chronic compartment syndrome are sporadic. Previous published case series affecting the upper limb have not used compartment pressure monitoring to aid diagnosis. In our chronic compartment pressure monitoring clinic we confirmed the diagnosis of four cases. Following these diagnoses a review of the literature showed that there was no definition of normal pre or post exercise pressure for the upper limb.

Aim: Acknowledging that diagnosis of forearm chronic compartment syndrome is largely based on clinical presentation supported by an ever increasing use of hand-held compartment pressure monitors, we felt it was important to establish what represented the normal pre and post exercise pressures in asymptomatic normal individuals to give a baseline upon which perceived raised pressures can be calculated against.

Methods: Ethical approval was obtained from Dorset Research and Ethics Committee. 41 participants underwent compartment pressure measurements of the superficial flexor and extensor compartments of the forearm before and five minutes following exercise. A Stryker intracompartmental pressuremonitor was used.

Results: Normal ranges for pre-exercise extensor compartment (2–27mmHg, CI 18.8–25.2mmHg), post-exercise extensor compartment (2–24mmHg, CI16.8–22.8mmHg), pre-exercise flexor compartment (1–19mHg, CI 13.3–17.4mmHg)) and post-exercise flexor compartment (0–19mmHg, CI 16–21.4) pressures were established. No significant difference was found between pressures before and after exercise (extensor pressures; p=0.41, flexor pressures; p=0.21). There was a significant difference between sexes (extensor pressures; p=0.04, flexor pressures; p=0.008)

Discussion: This study has established a significant difference in normal forearm compartment pressures between sexes. A normal reference range of forearm compartment pressures to aid diagnosis of chronic compartment syndrome has been determined. This can also be useful in diagnosing acute compartment syndrome.

Background: Chronic compartment syndrome is well recognised. Patients present with exercise-induced pain, relieved by rest. The condition is caused by increased intracompartmental pressure due to inadequate muscle compartment fascial size. Cases of forearm chronic compartment are sporadic. Previous published case series affecting the upper limb have not used compartment pressure monitoring to aid diagnosis. In our chronic compartment pressure monitoring clinic we confirmed the diagnosis of four cases. Following these a review of the literature showed that there was no definition of normal pre or post-exercise pressure for the upper limb.

Aim: This study aimed to establish the normal pre and post-exercise forearm pressures in asymptomatic normal individuals to give a baseline upon which perceived raised pressures could be calculated against.

Methods: Ethical approval was obtained from Dorset Research and Ethics Committee. 41 participants underwent compartment pressure measurements of the superficial extensor and flexor forearm compartments before and after five minutes of exercise. A Stryker intracom-partmental pressure monitor was used.

Results: Normal ranges for pre-exercise extensor compartment (2–27mmHg, upper CI 18.8–25.2mmHg), post-exercise extensor compartment (2–24mmHg, upper CI 16.8–22.8mmHg), pre-exercise flexor compartment (1–19mmHg, upper CI 13.3–17.4mmHg) and post-exercise flexor compartment (0–19mmHg, upper CI 16–21.4mmHg) pressures were established. No significant difference was found between pressures before and after exercise (extensor pressures; p=0.41, flexor pressures; p=0.21). There was a significant difference between sexes (extensor pressures; p=0.04, flexor pressures; p=0.008)

Conclusion: This study has shown a significant difference in normal forearm compartment pressures between sexes. No difference between pre and post-exercise pressure could be established. A normal reference range of forearm compartment pressures to aid diagnosis of chronic compartment syndrome has been determined. This may also prove useful in aiding the diagnosis of acute forearm compartment syndrome.