Learning curves in Motec total wrist arthroplasty: an international cohort study.

We examined the learning curve of Motec total wrist arthroplasty (TWA) of six experienced surgeons in their first 30 cases. Three times more complications/revisions were encountered in the first half of the study compared with the second half. Motec TWA surgery should be concentrated in a smaller number of centres performing higher volumes.

Complication rates and modes of short and medium-term failure in Motec total wrist arthroplasty: an international cohort study.

The aim of this study was to analyse the short- and medium-term complications of the Motec total wrist arthroplasty (TWA). Identifying exact modes of failure and their causes should allow surgeons to avoid or mitigate these risks in the future. Retrospective analysis of prospectively collected data from six hand surgeons at five international centres provided details of 171 Motec TWAs. The mean follow-up was 5.8 years (range 18 months to 12 years). There were 33 (19%) complications within our cohort, with a revision rate of 8.2% (14 revisions). There was no difference in complication rates between metal-on-metal and metal-on-polymer articulations. Failure of osseointegration was the most common complication. Problems with soft tissue balancing, implant impingement related osteolysis, bony impingement and metacarpal fracture were found to be other preventable causes of failure in this series. Elimination of these preventable complications will improve survival rates for this implant.Level of evidence: IV.

Arthroplasty in the hand: what works and what doesn't?

This review describes the different possibilities for arthroplasties at the proximal interphalangeal joint, thumb carpometacarpal joint, distal radioulnar joint, metacarpophalangeal joint and the wrist. For each joint, the indication for arthroplasty is explained, the surgical technique with the suitable implant is described and a brief summary of the outcomes reported in the literature is given.

Surface Replacement Proximal Interphalangeal Joint Arthroplasty: A Case Series.

Background: In 2012, our unit published our experience with a pyrocarbon proximal interphalangeal joint (PIPJ) implant. Due to high subsidence rates, a decision was made to change to a cemented surface replacement proximal interphalangeal joint (SR-PIPJ) implant. The purpose of this study was to assess whether the change to a cemented implant would improve the subsidence rates. Methods: Retrospective review of all patients who had a cemented SR-PIPJ arthroplasty performed from 2011 to 2013 with at least 12 months follow-up. Results: A total of 43 joints were included with an average follow-up of 26.5 months. There was a significant (P = .02) improvement in arc of motion with an average satisfaction score of 3.3 (satisfied patient). Subsidence was noted in 26% of joints with a significant difference in range of motion (P = .003) and patient satisfaction (P = .001) between the group with and without subsidence. Conclusions: The change to a cemented implant resulted in satisfied patients with an improvement in range of motion. The rate of subsidence improved but remains unacceptably high.

The flaws of laser Doppler in negative-pressure wound therapy research.

Recent studies, using modalities other than laser Doppler, have indicated that perfusion during negative-pressure wound therapy (NPWT) is reduced, contrary to world literature. The aim of the present study was to evaluate whether the measuring technique of the laser Doppler could be influenced by the compressive nature of NPWT dressings and whether this could explain the conflicting findings. A hypothesis that it may be possible for laser Doppler to record similar readings to those obtained during NPWT by merely compressing tissues manually was tested on 12 NPWT dressings, with each undergoing an alternating series of manual compressive forces and NPWT (-125 mmHg). During the periods of NPWT (n = 12), the mean perfusion recording increased in five experiments, reduced in six, and remained unchanged in one. During the period when manual pressure was applied (n = 12), there was a mean increase in perfusion in six experiments and a reduction in six. The type of change in perfusion (increase or decrease) was the same for both NPWT and manual pressure in 10 of the 12 experiments. In conclusion, laser Doppler can incorrectly record increased perfusion when tissues are compressed, implying that it is flawed in the field of NPWT research as tissues are always compressed to some degree by the NPWT dressing.

The influence manufacturers have on negative-pressure wound therapy research.

BACKGROUND: Studies investigating the effects of negative-pressure wound therapy using the Chariker-Jeter system (gauze-based interface) and the vacuum-assisted closure system often have outcomes that favor one particular system. This study attempts to examine whether manufacturer involvement could be related to the outcomes of these scientific studies. METHODS: A literature review was undertaken to identify a cohort of studies that compared these two forms of negative-pressure wound therapy. Clinical outcomes studies, basic research studies, and published conference abstracts were included. Allthe articles' abstracts and conclusions were given to five surgeons, who were blinded to the titles and authors. They were individually asked to record what they would consider to be the take-home message of each article (in terms of which system is superior). After categorizing each study according to the system that it appears to favor, the level of manufacturer involvement in each study was evaluated. The relationship between the outcome of a study and the level of manufacturer involvement in that study was then investigated. RESULTS: Of the total of 24 studies found to match the inclusion criteria, 22 were considered to favor a particular system (the other two were categorized as impartial). Of the 24 studies, 19 had some form of manufacturer involvement. Of the 19 that had some form of manufacturer involvement, 18 had outcomes that were deemed beneficial to the involved manufacturer, whereas one was deemed to have an impartial outcome. CONCLUSIONS: This study suggests that manufacturer involvement in these studies (regardless of level) correlates with the outcomes being beneficial to the involved manufacturer in almost all cases. Potential reasons for this and the implications thereof are discussed.

A Glomus Tumour of the Elbow: A Case Report and Review of the Literature.

Extradigital glomus tumours are relatively uncommon. We present a case report of a glomus tumour of the elbow and review of the literature with regards to the clinical features, work-up and management of these tumours, to highlight the importance of considering a glomus tumour as part of the differential diagnosis in patient with atypical pain around the elbow.

Conservative treatment of fractures of the proximal phalanx: an option even for unstable fracture patterns.

PURPOSE: The purpose of the study was to assess the efficacy of the conservative management of proximal phalangeal fractures in a dorsal plaster slab. METHODS: Twenty-three consecutive patients with extra-articular proximal phalangeal fractures were included in this prospective study. Fourteen patients (62%) presented with fractures considered unstable. The fractures were reduced and the position was held with a dorsal plaster slab for three weeks. The patients were followed up for an average of seven weeks (range 2 to 45) after the injury. Range of motion of the finger and radiological evidence of union, non-union or malunion was documented after removal of the plaster. RESULTS: Ninety-one percent of fractures maintained an acceptable reduction. All cases measured less than 15° of angulation. On average 1,1 mm of shortening was measured. In two (9%) cases the reduction was not accepted on follow up assessment and the fractures were managed surgically. CONCLUSION: Most extra-articular proximal phalanx fractures can be managed conservatively with acceptable results.

Does a zone of increased perfusion exist around negative-pressure dressings?

BACKGROUND: Although recent work has demonstrated that perfusion adjacent to a negative-pressure wound therapy dressing is decreased, laser Doppler studies have indicated that there is a zone of increased perfusion a couple of centimeters away. The existence of such a zone of increased perfusion is counterintuitive to the fact that negative-pressure wound therapy has been shown to increase tissue pressure. This study, using an alternative to laser Doppler, evaluated whether such a zone exists. METHODS: Six volunteers were randomized into three groups to test different suction pressures (-75, -125, and -400 mmHg). Each volunteer would have two dressings applied on either side of the lower back. A thermal imaging camera was used to assess perfusion around the dressing during different phases (e.g., "Suction on" and "Suction off"). The mean area under the curve for each phase was compared with those of other phases by means of one-way analysis of variance. Each condition (phase) was compared in a systematic manner with every other by means of Fisher's least significant difference for post hoc comparisons. A Pearson's correlation was determined to test the effects of the different suction pressure groups. RESULTS: No significant difference could be demonstrated for the area under the curve for the different phases. There was no significant correlation between the three suction pressures tested and the difference between the mean area under the curve for "Dressing on, no suction" and the two "Suction on" periods (Pearson correlation = 0.24; p > 0.4). CONCLUSIONS: Thermographic evaluation of tissue around a negative-pressure dressing did not demonstrate a zone of increased perfusion, contrary to other studies, which used laser Doppler. This is in keeping with recent work demonstrating that negative-pressure wound therapy increases tissue pressure while the dressing is applying suction. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

The paradox of negative pressure wound therapy--in vitro studies.

Negative-pressure wound therapy (NPWT) has revolutionised wound care. Yet, it is still not understood how hypobaric tissue pressure accelerates wound healing. There is very little reported on the relevant physics of any substance subjected to suction in this manner. The common assumption is that applying suction to a substance is likely to result in a reduction of pressure in that substance. Although more than 250 research articles have been published on NPWT, there are little data verifying whether suction increases or decreases the pressure of the substance it is applied to. Clarifying this basic question of physics is the first step in understanding the mechanism of action of these dressings. In this study, pressure changes were recorded in soft plasticene and processed meat, using an intracranial tissue pressure microsensor. Circumferential, non-circumferential and cavity NPWT dressings were applied, and pressure changes within the underlying substance were recorded at different suction pressures. Pressures were also measured at 1cm, 2 cm and 3 cm from the NPWT placed in a cavity. In all three types of NPWT dressings, the underlying substance pressure was increased (hyperbaric) as suction pressure increased. Although there was a substantial pressure increase at 1cm, the rise in pressure at the 2-cm and 3-cm intervals was minimal. Substance pressure beneath all types of NPWT dressing is hyperbaric in inanimate substances. Higher suction pressures generate greater substance pressures; however, the increased pressure rapidly dissipates as the distance from the dressing is increased. The findings of this study on inanimate objects suggest that we may need to review our current perception of the physics underlying NPWT dressings. Further research of this type on living tissues is warranted.

Negative-pressure wound therapy I: the paradox of negative-pressure wound therapy.

BACKGROUND: Does negative-pressure wound therapy reduce or increase the pressure of wound tissues? This seemingly obvious question has never been addressed by a study on living tissues. The aim of this study was to evaluate the nature of tissue pressure changes in relation to negative-pressure wound therapy. METHODS: Three negative-pressure wound therapy dressing configurations were evaluated-circumferential, noncircumferential, and those within a cavity-on 15 human wounds, with five wounds in each category. Tissue pressure changes were recorded (using a strain gauge sensor) for each 75-mmHg increment in suction, up to -450 mmHg. In the circumferential and noncircumferential groups, tissue pressure was also measured over a 48-hour period at a set suction pressure of -125 mmHg (n = 10). RESULTS: In all three groups, mean tissue pressure increased proportionately to the amount of suction applied (p < 0.0005). Mean tissue pressure increments resulting from the circumferential dressings were significantly higher than those resulting from the noncircumferential (p < 0.0005) or cavity group (p < 0.0005); however, there was no significant difference between the latter two groups (p = 0.269). Over the 48-hour period, there was a significant mean reduction in the (increased) tissue pressure (p < 0.04 for circumferential and p < 0.0005 for noncircumferential), but in only three of 10 cases did this reduce to pressures less than those before dressing application. CONCLUSIONS: Negative-pressure wound therapy increases tissue pressure proportionately to the amount of suction, although this becomes less pronounced over 48 hours. This suggests that negative-pressure wound therapy dressings should be used with caution on tissues with compromised perfusion, particularly when they are circumferential.

Negative-pressure wound therapy II: negative-pressure wound therapy and increased perfusion. Just an illusion?

BACKGROUND: A recent study demonstrated that negative-pressure wound therapy increases underlying tissue pressure. This finding is incongruous with studies using laser Doppler that show that perfusion is immediately increased on initiation of suction. This study investigated perfusion in negative-pressure wound therapy using two alternative modalities. METHODS: Radioisotope perfusion imaging was used to determine perfusion beneath circumferential negative-pressure wound therapy dressings on 20 healthy hands (n = 20). Ten hands received suction pressures of -400 mmHg and 10 received -125 mmHg, with the contralateral hand used as a control without any suction. Transcutaneous partial pressure of oxygen was used to determine perfusion beneath noncircumferential negative-pressure wound therapy dressings on 12 healthy legs (n = 12), with each volunteer being sequentially randomized to receive suction pressures of -400 and -125 mmHg, respectively. RESULTS: Tissues undergoing circumferential negative-pressure wound therapy demonstrated a mean reduction in perfusion of 40 +/- 11.5 percent (p < 0.0005) and 17 +/- 8.9 percent (p < 0.0005) at suction pressures of -400 mmHg and -125 mmHg, respectively. Perfusion reduction at -400 mmHg was significantly greater than at -125 mmHg (p < 0.015). In the noncircumferential negative-pressure wound therapy group, there was a mean reduction in transcutaneous partial pressure of oxygen of 7.35 +/- 7.4 mmHg (p < 0.0005) and 5.10 +/- 7.4 mmHg (p < 0.0005) at suction pressures of -400 mmHg and -125 mmHg, respectively. There was a tendency for greater reductions in the -400 mmHg group, but this was not significantly different from the -125 mmHg group (p = 0.07). CONCLUSIONS: These findings demonstrate that perfusion beneath negative-pressure wound therapy decreases for increasing suction pressure. Thus, it is suggested that negative-pressure wound therapy should be used with caution on tissues with compromised vascularity, particularly when used circumferentially.

A device for zone-II flexor tendon repair. Surgical technique.

BACKGROUND: The stainless-steel Teno Fix tendon-repair device has improved biomechanical characteristics compared with those of suture repair, and it was well tolerated in a canine model. The purpose of this study was to compare the Teno Fix with suture repair in a clinical setting. METHODS: Sixty-seven patients with isolated zone-II flexor tendon injury were randomized to be treated with a Teno Fix or a four-stranded cruciate suture repair. There were eighty-five injured digits: thirty-four were treated with the Teno Fix, and fifty-one served as controls. A modified leinert rehabilitation technique was employed, with active flexion starting at four weeks postoperatively. Patients were followed for six months by blinded observers who determined the range of motion, Disabilities of the Arm, Shoulder and Hand (DASH) score, pinch and grip strength, and pain score on a verbal scale and assessed swelling and neurologic recovery. Adverse outcomes, including device migration and rupture, were monitored at frequent intervals. RESULTS: Nine of the fifty-one suture repairs ruptured, whereas none of the Teno Fix repairs ruptured (p < 0.01). Five of the nine ruptures were caused by resistive motion against medical advice. There were no differences between the two groups in terms of range of motion, DASH score, pinch and grip strength, pain, swelling, or neurologic recovery. The Teno Fix group had slightly slower resolution of pain and swelling compared with the control group. Of the patients who were available for follow-up at six months, sixteen of the twenty-four treated with a Teno Fix repair and nineteen of the twenty-seven treated with a control repair had a good or excellent result. One Teno Fix device migrated and extruded secondary to a wound infection. Of all eighty-five digits that were operated on, four were thought to have tendons of inadequate size to accommodate the device and nine were deemed to have inadequate exposure to allow placement of the anchors. CONCLUSIONS: The Teno Fix is safe and effective for flexor tendon repair if the tendon size and exposure are sufficient. Tendon repairs with the Teno Fix have lower rupture rates and similar functional outcomes when compared with conventional repair, particularly in patients who are non-compliant with the rehabilitation protocol.